The paper was to evaluate the efficient seasons for embryo transfer of cattle in different climatic zones in China. Three climatic zones(mid-temperate zone,warm temperate zone,subtropical zone) were designed,and embry...The paper was to evaluate the efficient seasons for embryo transfer of cattle in different climatic zones in China. Three climatic zones(mid-temperate zone,warm temperate zone,subtropical zone) were designed,and embryo transfers had been carried out in spring,summer,autumn and winter from 2009 to 2011,respectively. The total number of transplant recipient cattle was 22 208. The results showed that the best seasons for embryo transfers varied with different climatic zones. In mid-temperate zone,summer and autumn were better while summer was the best,and the rate of pregnant was 50. 67%(the number of pregnant cattle was 8 005). In warm temperate zone,spring and autumn were better while autumn was the best,and the rate of pregnant was 54. 99 %(the number of pregnant cattle was 551). In subtropical zone,spring and winter were better while winter was the best,and the rate of pregnant was 56. 94 %(the number of pregnant cattle was 328). The seasonal average temperatures and relative humidity of the best seasons in different climatic zones were concentrated on the same region. In mid-temperate zone,the mean temperature ranged between 22. 4 ℃ and 24. 2 ℃,and the mean relative humidity ranged from 44% to 55. 3%. In warm zone,the mean temperature ranges were between 14. 2 ℃ and 16. 2 ℃,and the mean relative humidity ranges were from 59. 3% to 71. 6%. In sub-tropical zone,the mean temperature ranges were between 3. 26 ℃ and 7. 73 ℃,and the mean relative humidity ranges were from 72% to 80. 6%. Therefore,the optimized conditions of temperature and humidity of season in different zones could be simulated. It is possible that we apply the program to bovine production in the similar agroecological zones,which is of great significance for improving the embryo transfer efficiency of livestock in production.展开更多
The utilization of energy in building sectors comprises 30–40%of the entire global energy consumption.Most of the energy is being utilized for cooling&heating the buildings.These cooling and heating depend on the...The utilization of energy in building sectors comprises 30–40%of the entire global energy consumption.Most of the energy is being utilized for cooling&heating the buildings.These cooling and heating depend on the nature of climate for different places.In this,the detailed analysis of the building envelope across five areas(viz.Srinagar,Jaisalmer,New Delhi,Thiruvananthapuram and Bangalore)representing different climatic zones had been carried out.Simulations are performed for these locations using eQUEST and ANSYS software.Three of the result output from the eQUEST simulation are used to assess the different cases.These outputs are:total electrical energy consumption of the year,peak cooling load&peak heating load for a particular time of the year.Temperature variations and airflow for a fan with moisture influence are also simulated for five different locations by using the radiation model and shear stress transport in ANSYS.The internal temperature distribution in accordance with an occupant is also compared and discussed for the five regions.Lastly,the predicted mean vote and predicted percentage of dissatisfaction are found to be in the range of−0.50 to−0.99 for all zones that signifies 13%to 30%of people are dissatisfied with the indoor environment.展开更多
Elevational patterns of tree diversity are well studied worldwide.However,few studies have examined how seedlings respond to elevational gradients and whether their responses vary across climatic zones.In this study,w...Elevational patterns of tree diversity are well studied worldwide.However,few studies have examined how seedlings respond to elevational gradients and whether their responses vary across climatic zones.In this study,we established three elevational transects in tropical,subtropical and subalpine mountain forests in Yunnan Province,southern China,to examine the responses of tree species and their seedlings to elevational gradients.Within each transect,we calculated species diversity indices and composition of both adult trees and seedlings at different elevations.For both adult trees and seedlings,we found that species diversity decreased with increasing elevation in both tropical and subalpine transects.Species composition showed significant elevational separation within all three transects.Many species had specific elevational preferences,but abundant tree species that occurred at specific elevations tended to have very limited recruitment in the understory.Our results highlight that the major factors that determine elevational distributions of tree species vary across climatic zones.Specifically,we found that the contribution of air temperature to tree species composition increased from tropical to subalpine transects,whereas the contribution of soil moisture decreased across these transects.展开更多
Arid regions are highly vulnerable and sensitive to drought. The crops cultivated in arid zones are at high risk due to the high evapotranspiration and water demands. This study analyzed the changes in seasonal and an...Arid regions are highly vulnerable and sensitive to drought. The crops cultivated in arid zones are at high risk due to the high evapotranspiration and water demands. This study analyzed the changes in seasonal and annual evapotranspiration(ET) during 1951–2016 at 50 meteorological stations located in the extremely arid, arid, and semi-arid zones of Pakistan using the Penman Monteith(PM) method. The results show that ET is highly sensitive and positively correlated to temperature, solar radiation, and wind speed whereas vapor pressure is negatively correlated to ET. The study also identifies the relationship of ET with the meteorological parameters in different climatic zones of Pakistan. The significant trend analysis of precipitation and temperature(maximum and minimum) are conducted at 95% confidence level to determine the behaviors of these parameters in the extremely arid, arid, and semi-arid zones. The mean annual precipitation and annual mean maximum temperature significantly increased by 0.828 mm/a and 0.014℃/a in the arid and extremely arid zones, respectively. The annual mean minimum temperature increased by 0.017℃/a in the extremely arid zone and 0.019℃/a in the arid zone, whereas a significant decrease of 0.007℃/a was observed in the semi-arid zone. This study provides probabilistic future scenarios that would be helpful for policy-makers, agriculturists to plan effective irrigation measures towards the sustainable development in Pakistan.展开更多
This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We ev...This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We evaluated ecosystem services based on biophysical indicators using an expert scoring system that determines the corresponding soil functions and is part of the existing databases available in Slovakia. This methodological combination enabled us to provide unique mapping and assessment of ecosystem services within Slovakia. Correlation analysis between individual regulating ecosystem services and climate regions, slope, texture, and altitude confirm the statistically significant influence of climate and slope in all agricultural land, arable land, and grassland ecosystems. Statistically significant synergistic effects were established between the regulation of the water regime and the regulation of soil erosion within each climate region, apart from the very warm climate region. Only in a very warm climate region was potential of regulating ecosystem services mutually beneficial for soil erosion control and soil cleaning potential (immobilization of inorganic pollutants).展开更多
The climate has an impact on the urban thermal environment,and the magnitude of the surface urban heat island(SUHI)and urban cool island(UCI)vary across the world’s climatic zones.This literature review investigated:...The climate has an impact on the urban thermal environment,and the magnitude of the surface urban heat island(SUHI)and urban cool island(UCI)vary across the world’s climatic zones.This literature review investigated:1)the variations in the SUHI and UCI intensity under different climatic backgrounds,and 2)the effect of vegetation types,landscape composition,urban configuration,and water bodies on the SUHI.The SUHI had a higher intensity in tropical(Af(tropical rainy climate,Köppen climate classification),Am(tropical monsoon climate),subtropical(Cfa,subtropical humid climate),and humid continental(Dwa,semi-humid and semi-arid monsoon climate)climate zones.The magnitude of the UCI was low compared to the SUHI across the climate zones.The cool and dry Mediterranean(Cfb,temperate marine climate;Csb,temperate mediterranean climate;Cfa)and tropical climate(Af)areas had a higher cooling intensity.For cities with a desert climate(BWh,tropical desert climate),a reverse pattern was found.The difference in the SUHI in the night-time was greater than in the daytime for most cities across the climate zones.The extent of green space cooling was related to city size,the adjacent impervious surface,and the local climate.Additionally,the composition of urban landscape elements was more significant than their configuration for sustaining the urban thermal environment.Finally,we identified future research gaps for possible solutions in the context of sustainable urbanization in different climate zones.展开更多
Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperatu...Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.展开更多
This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble...This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble of 14 CORDEX-AFRICA simulations under RCP4.5 and RCP8.5 scenarios. The results indicate the existence of three climate zones in Côte d’Ivoire (the coastal, the centre and the north) over the historical period (1981-2005). Moreover, CORDEX simulations project an extension of the surface area of drier climatic zones while a reduction of wetter zones, associated with the appearance of an intermediate climate zone with surface area varying from 77,560 km<sup>2</sup> to 134,960 km<sup>2</sup> depending on the period and the scenario. These results highlight the potential impacts of climate change on the delimitation of the climate zones of Côte d’Ivoire under the greenhouse gas emission scenarios. Thus, there is a reduction in the surface areas suitable for the production of cash crops such as cocoa and coffee. This could hinder the country’s economy and development, mainly based on these cash crops.展开更多
Considering four different climate zones in China, an investigation on the choice of heat recovery ventilator for the buildings with little moisture emissions is carried out. The annual composition of energy consumpti...Considering four different climate zones in China, an investigation on the choice of heat recovery ventilator for the buildings with little moisture emissions is carried out. The annual composition of energy consumption of air intake for per unitary air ventilation flow rate is evaluated by employing the testing data of climatic parameters in eight selected cities. The analysis shows that the total heat recovery is suitable in a controlled ventilation system with air humidity controlled during heating period of all the climates. For the building without air humidity controlled in winter, the sensible heat recovery ventilators can be used in severe cold and cold regions, and total heat recovery systems are more suitable for energy saving in hot summer and cold winter and hot summer and warm winter regions.展开更多
Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature ...Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature warms by 0.16℃/1 0a in Guangdong. The range of warming was lower than the average of nationwide and global land surface. Furthermore, the temperature has a larger increase tendency in winter and spring and coastal areas than in summer and autumn and inland areas. Climate zones move towards the north obviously. North tropical zone is expanding, south subtropical zone is reducing and central subtropical zone is relatively stable. Under the global climate warming, characteristics of climate warming in Guangdong were influenced by atmosphere general circulation, sea surface temperature and human activities etc.展开更多
[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average e...[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average extreme minimum temperature, annual average temperature, accumulative temperature ≥10 ℃ and annual rainfall as climatic zoning factors, regression model between zoning factors and geographic information was established, and comprehensive climatic zoning indicator of tea tree cultivation in Hanzhong was determined. [ Result] Tea tree cultivation in Hanzhong was divided into suitable, more suitable and unsuitable planting zones by using critical value of climatic zoning. [ Conclusion] The research could provide scientific basis for reasonable planning layout and sustainable development of tea tree in the whole city.展开更多
For analysis and evaluation of potential of agroecosystem (arable land and grassland) services (provisioning, regulating and cultural) in Slovakia we have created a mapping unit combining these input layers: slope top...For analysis and evaluation of potential of agroecosystem (arable land and grassland) services (provisioning, regulating and cultural) in Slovakia we have created a mapping unit combining these input layers: slope topography, soil texture and landuse in four climatic regions. Evaluated potential of agroecosystem services was categorised into five categories (very low, low, medium, high and very high). Our results show that climate has the most significant impact on agroecosystem services. Warm, dry lowland region has a higher potential of provisioning services, regulation of water regime, filtration of pollutants and control of soil erosion in comparison to moderately warm and cold regions. In moderate cold region, more than 90% of the total area of arable land has low potential of water regime regulation and cleaning potential (immobilization of risk elements). In the moderate warm climatic region, there is a high share of categories of low and moderate potential of provisioning services and low and moderate potential of water regime regulation. Majority of the total area of warm climatic region belongs to the categories of moderate to high potential of provisioning services and high potential of regulation of water regime. In this climatic zone low potential categories of risk elements immobilization are present in more than 65% of the arable land total area. On the other hand, in very warm climatic zone, more than 89% of the total area of arable land belongs to the category with a very high cleaning (buffering) potential. Potential of natural conditions for recreation is higher only in moderate cold and moderate warm climatic zones with a higher proportion of area of grassland agroecosystems and protected areas NATURA 2000. Moreover, the methodology developed in this paper is replicable and could be applied by planners in the case that they are proficient in geographical information systems.展开更多
Based on the building height and density data on a 100-m resolution,hourly 2-m temperature and humidity data at83 automatic weather stations,and gridded local climate zone(LCZ)data on a 120-m resolution in urban Beiji...Based on the building height and density data on a 100-m resolution,hourly 2-m temperature and humidity data at83 automatic weather stations,and gridded local climate zone(LCZ)data on a 120-m resolution in urban Beijing in2020,this study first employs the semivariogram combined with building parameters to calculate spatial correlations and has identified an LCZ grid resolution of 500 m suitable for best usage of the available observation data.Then,how the spatially heterogeneous LCZs affect and contribute to the canopy urban heat island intensity(UHII)and urban dry island intensity(UDII)are quantitatively investigated.It is found that UHII is high in winter and low in summer with a unimodal diurnal variation while UDI is low in winter but high in summer with a bimodal diurnal variation.The LCZ with compact mid-rise(open high-rise)buildings exhibits the highest UHII(UDII),followed by the compact high-rise(compact low-rise),while the LCZ of scattered trees presents both the lowest UHII and the lowest UDII.The most significant difference in the UHII(UDII)among the nine LCZ types in the urban area of Beijing is2.62℃(1.1 g kg^(-1)).Area-weighted averaging analysis reveals that the open mid-rise LCZ is the most significant contributor to the UHII(UDII),immediately followed by compact mid-rise(open low-rise),with the least contribution from bare rock or paved(scattered trees).The results also indicate that beyond the intrinsic physical properties of the LCZs of a city,their area proportions cannot be overlooked in evaluating their impact on the UHI and UDI.These quantitatively findings could help urban planners to create a livable urban climate and environment by adjusting the relevant land use.展开更多
Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal...Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal, annual and spatial variation characteristics of urban heat island effect in Weihai City in the past 10 years. The results showed that in recent 10 years, the average urban heat island intensity was 1.24 ℃, showing a gradual weakening trend of -0.169 3 ℃/10 a;the summer average heat island intensity was 0.86 ℃, showing a gradual weakening trend of -0.047 5 ℃/10 a. The heat island intensity had obvious diurnal variation characteristics, that is, "it was weak in the day and strong at night". In terms of seasonal variation, heat island effect was the weakest in summer, stronger in spring and autumn, and the strongest in winter. The diurnal, seasonal and annual changes of heat island intensity showed a reverse trend to those of temperature. The high-value area of urban heat island was highly consistent with human residential activity areas and industrial and commercial intensive areas, and the extension trend of heat island intensity was the same as the direction of urban development and construction. The "cold island phenomenon" in some offshore areas was related to the geographical location, terrain and the southeast monsoon trend in summer. The adverse effects of urban heat island effect can be reduced by optimizing the types and distribution of vegetation communities, rationally planning and constructing urban water body, promoting green building materials and adjusting shape design, etc.展开更多
A radiant floor cooling system(RFCS)is a high-comfort and low energy consumption system suitable for residential buildings.Radiant floor systems usually work with fresh air,and their operating performance is affected ...A radiant floor cooling system(RFCS)is a high-comfort and low energy consumption system suitable for residential buildings.Radiant floor systems usually work with fresh air,and their operating performance is affected by climatic conditions.Indoor and outdoor environmental disturbances and the system’s control strategy affect the indoor thermal comfort and energy efficiency of the system.Firstly,a multi-story residential building model was established in this study.Transient system simulation program was used to study the operation dynamics of three control strategies of the RFCS based on the calibrated model.Then,the performance of the control strategies in five climate zones in China were compared using multi-criteria decision-making in combination.The results show that control strategy has a negligible effect on condensation risk,but the thermal comfort and economic performance differ for different control strategies.The adaptability of different control strategies varies in different climate zones based on the consideration of multiple factors.The performance of the direct-ground cooling source system is better in Hot summer and warm winter zone.The variable air volume control strategy scores higher in Serve cold and Temperate zones,and the hours exceeding thermal comfort account for less than 3%of the total simulation period.Therefore,it is suggested to choose the RFCS control strategy for residential buildings according to the climate zone characteristics,to increase the energy savings.Our results provide a reliable reference for implementing RFCSs in residential buildings.展开更多
Background Previous studies provided some evidence of meteorological factors influence seasonal influenza transmission patterns varying across regions and latitudes. However, research on seasonal influenza activities ...Background Previous studies provided some evidence of meteorological factors influence seasonal influenza transmission patterns varying across regions and latitudes. However, research on seasonal influenza activities based on climate zones are still in lack. This study aims to utilize the ecological-based Koppen Geiger climate zones classification system to compare the spatial and temporal epidemiological characteristics of seasonal influenza in Chinese mainland and assess the feasibility of developing an early warning system.Methods Weekly influenza cases number from 2014 to 2019 at the county and city level were sourced from China National Notifiable Infectious Disease Report Information System. Epidemic temporal indices, time series seasonality decomposition, spatial modelling theories including Moran’s/ and local indicators of spatial association were applied to identify the spatial and temporal patterns of influenza transmission.Results All climate zones had peaks in Winter-Spring season. Arid, desert, cold (BWk) showed up the first peak. Only Tropical, savannah (Aw) and Temperate, dry winter with hot summer (Cwa) zones had unique summer peak. Temperate, no dry season and hot summer (Cfa) zone had highest average incidence rate (IR) at 1.047/100,000. The Global Moran’s/ showed that average IR had significant clustered trend (z = 53.69,P < 0.001), with local Moran’s/ identified high-high cluster in Cfa and Cwa. IR differed among three age groups between climate zones (0-14 years old:F = 26.80,P < 0.001;15-64 years old:F = 25.04,P < 0.001;Above 65 years old:F = 5.27,P < 0.001). Age group 0-14 years had highest average IR in Cwa and Cfa (IR= 6.23 and 6.21) with unique dual peaks in winter and spring season showed by seasonality decomposition.Conclusions Seasonal influenza exhibited distinct spatial and temporal patterns in different climate zones. Seasonal influenza primarily emerged in BWk, subsequently in Cfa and Cwa. Cfa, Cwa and BSk pose high risk for seasonal influenza epidemics. The research finds will provide scientific evidence for developing seasonal influenza early warning system based on climate zones.展开更多
Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess f...Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess future changes in surface air temperature,precipitation and Köppen-Trewartha(K-T)climate types in Northern Asia under the 1.5-4℃global warming targets.RegCM4 is driven by five CMIP5 global models over an East Asia domain at a grid spacing of 25 km.Validation of the present day(1986-2005)simulations shows that the ensembles of RegCM4(ensR)and driving GCMs(ensG)reproduce the major characters of the observed temperature,precipitation and K-T climate zones reasonably well.Greater and more realistic spatial detail is found in RegCM4 compared to the driving GCMs.A general warming and overall increases in precipitation are projected over the region,with these changes being more pronounced at higher warming levels.The projected warming by ensR shows different spatial patterns,and is in general lower,compared to ensG in most months of the year,while the percentage increases of precipitation are maximum during the cold months.The future changes in K-T climate zones are characterized by a substantial expansion of Dc(temperature oceanic)and retreat of Ec(sub-arctic continental)over the region,reaching∼20%under the 4℃warming level.The most notable change in climate types in ensR is found over Japan(∼60%),followed by Southern Siberia,Mongolia,and the Korean Peninsula(∼40%).The largest change in the K-T climate types is found when increasing from 2 to 3℃.The results will help to better assess the impacts of climate change and in implementation of appropriate adaptation measures over the region.展开更多
This study focuses on carbon emissions of the building sector in relation to local climate zone(LCZ)classification,concentrating on two major parts.First,we estimated carbon emissions in the building sector,which were...This study focuses on carbon emissions of the building sector in relation to local climate zone(LCZ)classification,concentrating on two major parts.First,we estimated carbon emissions in the building sector,which were cal-culated for weekdays and weekends real-time daily energy consumption patterns.The estimations were divided into direct(from petroleum products consumption)and indirect emissions(from electricity consumption).Sec-ond,we examined urban carbon emissions mapping in relation to LCZ.Bangkok Metropolitan Administration(BMA)was used as the case study and 2016 as the base year for examination.The results illustrate that indirect emissions in Bangkok can be up to ten times higher than direct emissions.The analysis indicates that LCZ,such as compact high-rise,large low-rise,light industry,and warehouse zones had a relatively higher carbon emission intensity than others.Additionally,we identified that the compact high-rise zone has the highest indirect emission intensity,while the light industry and warehouse zone have the greatest direct emission intensity.These results provide insights into the dynamics of carbon emission characteristics in the building sector and the methodology purported here can be used to support low carbon city planning and policymaking in Bangkok.展开更多
The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China (NW) dominates the main arid areas in China. T...The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China (NW) dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years (1981-2010) from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique (FC), an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs.展开更多
The Cretaceous was one of the most remarkable 'greenhouse' climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial ...The Cretaceous was one of the most remarkable 'greenhouse' climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial scale paleoclimatic reconstruction, which has a higher time resolution based upon continental sediments in China, is rarely found. This study presents paleoclimate reconstruction for the six time periods of the Early Cretaceous in China by employing continental climate-indicative sediments, including calcareous deposits, coal, oil shale, gypsum, halite, desert sedimentary systems, ferruginous deposits and laterite, copper-bearing deposits, limestone and dolomite. Based on the distribution of the association of climate-indicative sediments and the influences of paleotopography and orogenic belts (or important structural belts) on climate, seven climatic zones have been identified: 1) a warm and humid zone; 2) a warm and humid-warm and arid zone; 3) a warm and arid zone; 4) an arid and hot zone; 5) the Tibet hot and humid zone; 6) a hot and arid-semiarid zone; and 7) a hot and humid-hot and arid one. It is found that the Early Cretaceous climatic zones of China were nearly latitudinally distributed from northwest to southeast. The arid- hot climatic zone expanded in the Aptian, suggesting that a hotter and drier climate prevailed in later period of the Early Cretaceous. Conversely, the humid climatic zone expanded in the Albian, indicating that a wetter climate appeared at the end of the Early Cretaceous. The overall distribution pattern of the seven climatic zones indicates that a hot-warm and arid climate was predominant in China; this coincides with a global 'greenhouse climate' background. However, palaeogeographic features and specific geologic events, such as the existence and disappearance of the eastern high plateau, and the uplift and denudation of Yinshan, Yanshan, Tianshan, Qinling and Dabie Mountains, led to distinctive regional climatic features of the Cretaceous in China.展开更多
文摘The paper was to evaluate the efficient seasons for embryo transfer of cattle in different climatic zones in China. Three climatic zones(mid-temperate zone,warm temperate zone,subtropical zone) were designed,and embryo transfers had been carried out in spring,summer,autumn and winter from 2009 to 2011,respectively. The total number of transplant recipient cattle was 22 208. The results showed that the best seasons for embryo transfers varied with different climatic zones. In mid-temperate zone,summer and autumn were better while summer was the best,and the rate of pregnant was 50. 67%(the number of pregnant cattle was 8 005). In warm temperate zone,spring and autumn were better while autumn was the best,and the rate of pregnant was 54. 99 %(the number of pregnant cattle was 551). In subtropical zone,spring and winter were better while winter was the best,and the rate of pregnant was 56. 94 %(the number of pregnant cattle was 328). The seasonal average temperatures and relative humidity of the best seasons in different climatic zones were concentrated on the same region. In mid-temperate zone,the mean temperature ranged between 22. 4 ℃ and 24. 2 ℃,and the mean relative humidity ranged from 44% to 55. 3%. In warm zone,the mean temperature ranges were between 14. 2 ℃ and 16. 2 ℃,and the mean relative humidity ranges were from 59. 3% to 71. 6%. In sub-tropical zone,the mean temperature ranges were between 3. 26 ℃ and 7. 73 ℃,and the mean relative humidity ranges were from 72% to 80. 6%. Therefore,the optimized conditions of temperature and humidity of season in different zones could be simulated. It is possible that we apply the program to bovine production in the similar agroecological zones,which is of great significance for improving the embryo transfer efficiency of livestock in production.
文摘The utilization of energy in building sectors comprises 30–40%of the entire global energy consumption.Most of the energy is being utilized for cooling&heating the buildings.These cooling and heating depend on the nature of climate for different places.In this,the detailed analysis of the building envelope across five areas(viz.Srinagar,Jaisalmer,New Delhi,Thiruvananthapuram and Bangalore)representing different climatic zones had been carried out.Simulations are performed for these locations using eQUEST and ANSYS software.Three of the result output from the eQUEST simulation are used to assess the different cases.These outputs are:total electrical energy consumption of the year,peak cooling load&peak heating load for a particular time of the year.Temperature variations and airflow for a fan with moisture influence are also simulated for five different locations by using the radiation model and shear stress transport in ANSYS.The internal temperature distribution in accordance with an occupant is also compared and discussed for the five regions.Lastly,the predicted mean vote and predicted percentage of dissatisfaction are found to be in the range of−0.50 to−0.99 for all zones that signifies 13%to 30%of people are dissatisfied with the indoor environment.
基金supported by the National Natural Science Foundation of China(31800353 and 32061123003)the West Light Foundation of the Chinese Academy of Sciences,the Applied Fundamental Research Foundation of Yunnan Province(2019FB038,2014GA003 and 2013FB079)the National Key Basic Research Program of China(2014CB954100)and the QueenslandeChinese Academy of Sciences Biotechnology Fund(GJHZ1130).
文摘Elevational patterns of tree diversity are well studied worldwide.However,few studies have examined how seedlings respond to elevational gradients and whether their responses vary across climatic zones.In this study,we established three elevational transects in tropical,subtropical and subalpine mountain forests in Yunnan Province,southern China,to examine the responses of tree species and their seedlings to elevational gradients.Within each transect,we calculated species diversity indices and composition of both adult trees and seedlings at different elevations.For both adult trees and seedlings,we found that species diversity decreased with increasing elevation in both tropical and subalpine transects.Species composition showed significant elevational separation within all three transects.Many species had specific elevational preferences,but abundant tree species that occurred at specific elevations tended to have very limited recruitment in the understory.Our results highlight that the major factors that determine elevational distributions of tree species vary across climatic zones.Specifically,we found that the contribution of air temperature to tree species composition increased from tropical to subalpine transects,whereas the contribution of soil moisture decreased across these transects.
文摘Arid regions are highly vulnerable and sensitive to drought. The crops cultivated in arid zones are at high risk due to the high evapotranspiration and water demands. This study analyzed the changes in seasonal and annual evapotranspiration(ET) during 1951–2016 at 50 meteorological stations located in the extremely arid, arid, and semi-arid zones of Pakistan using the Penman Monteith(PM) method. The results show that ET is highly sensitive and positively correlated to temperature, solar radiation, and wind speed whereas vapor pressure is negatively correlated to ET. The study also identifies the relationship of ET with the meteorological parameters in different climatic zones of Pakistan. The significant trend analysis of precipitation and temperature(maximum and minimum) are conducted at 95% confidence level to determine the behaviors of these parameters in the extremely arid, arid, and semi-arid zones. The mean annual precipitation and annual mean maximum temperature significantly increased by 0.828 mm/a and 0.014℃/a in the arid and extremely arid zones, respectively. The annual mean minimum temperature increased by 0.017℃/a in the extremely arid zone and 0.019℃/a in the arid zone, whereas a significant decrease of 0.007℃/a was observed in the semi-arid zone. This study provides probabilistic future scenarios that would be helpful for policy-makers, agriculturists to plan effective irrigation measures towards the sustainable development in Pakistan.
文摘This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We evaluated ecosystem services based on biophysical indicators using an expert scoring system that determines the corresponding soil functions and is part of the existing databases available in Slovakia. This methodological combination enabled us to provide unique mapping and assessment of ecosystem services within Slovakia. Correlation analysis between individual regulating ecosystem services and climate regions, slope, texture, and altitude confirm the statistically significant influence of climate and slope in all agricultural land, arable land, and grassland ecosystems. Statistically significant synergistic effects were established between the regulation of the water regime and the regulation of soil erosion within each climate region, apart from the very warm climate region. Only in a very warm climate region was potential of regulating ecosystem services mutually beneficial for soil erosion control and soil cleaning potential (immobilization of inorganic pollutants).
基金Under the auspices of the National Natural Science Foundation of China(No.41590841)the National Key Research and Development Program of China(No.2016YFC0503000)the Research Funds of the Chinese Academy of Sciences the Chinese Academy of Sciences(CAS)-the World Academy of Sciences(TWAS)President’s Fellowship。
文摘The climate has an impact on the urban thermal environment,and the magnitude of the surface urban heat island(SUHI)and urban cool island(UCI)vary across the world’s climatic zones.This literature review investigated:1)the variations in the SUHI and UCI intensity under different climatic backgrounds,and 2)the effect of vegetation types,landscape composition,urban configuration,and water bodies on the SUHI.The SUHI had a higher intensity in tropical(Af(tropical rainy climate,Köppen climate classification),Am(tropical monsoon climate),subtropical(Cfa,subtropical humid climate),and humid continental(Dwa,semi-humid and semi-arid monsoon climate)climate zones.The magnitude of the UCI was low compared to the SUHI across the climate zones.The cool and dry Mediterranean(Cfb,temperate marine climate;Csb,temperate mediterranean climate;Cfa)and tropical climate(Af)areas had a higher cooling intensity.For cities with a desert climate(BWh,tropical desert climate),a reverse pattern was found.The difference in the SUHI in the night-time was greater than in the daytime for most cities across the climate zones.The extent of green space cooling was related to city size,the adjacent impervious surface,and the local climate.Additionally,the composition of urban landscape elements was more significant than their configuration for sustaining the urban thermal environment.Finally,we identified future research gaps for possible solutions in the context of sustainable urbanization in different climate zones.
基金Under the auspices of National Natural Science Foundation of China(No.42271214,41961027)Key Program of Natural Science Foundation of Gansu Province(No.21JR7RA278,21JR7RA281)+1 种基金the CAS‘Light of West China’Program(No.2020XBZGXBQNXZ-A)Basic Research Top Talent Plan of Lanzhou Jiaotong University(No.2022JC01)。
文摘Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.
文摘This study assesses the projected changes in the climate zoning of Côte d’Ivoire using the hierarchical classification of principal components (HCPC) method applied to the daily precipitation data of an ensemble of 14 CORDEX-AFRICA simulations under RCP4.5 and RCP8.5 scenarios. The results indicate the existence of three climate zones in Côte d’Ivoire (the coastal, the centre and the north) over the historical period (1981-2005). Moreover, CORDEX simulations project an extension of the surface area of drier climatic zones while a reduction of wetter zones, associated with the appearance of an intermediate climate zone with surface area varying from 77,560 km<sup>2</sup> to 134,960 km<sup>2</sup> depending on the period and the scenario. These results highlight the potential impacts of climate change on the delimitation of the climate zones of Côte d’Ivoire under the greenhouse gas emission scenarios. Thus, there is a reduction in the surface areas suitable for the production of cash crops such as cocoa and coffee. This could hinder the country’s economy and development, mainly based on these cash crops.
基金National Natural Science Foundation of China(Grant No50578034)Shanghai Educational Development Foundationtitled"Shuguang Project"(Grant NO03SG30)
文摘Considering four different climate zones in China, an investigation on the choice of heat recovery ventilator for the buildings with little moisture emissions is carried out. The annual composition of energy consumption of air intake for per unitary air ventilation flow rate is evaluated by employing the testing data of climatic parameters in eight selected cities. The analysis shows that the total heat recovery is suitable in a controlled ventilation system with air humidity controlled during heating period of all the climates. For the building without air humidity controlled in winter, the sensible heat recovery ventilators can be used in severe cold and cold regions, and total heat recovery systems are more suitable for energy saving in hot summer and cold winter and hot summer and warm winter regions.
基金Key project from Natural Science Foundation of China (40231009)
文摘Based on temperature data in Guangdong in the past 50years, statistical methods are used to analyze the characteristics of temperature in spatial and temporal variation. The results show that land surface temperature warms by 0.16℃/1 0a in Guangdong. The range of warming was lower than the average of nationwide and global land surface. Furthermore, the temperature has a larger increase tendency in winter and spring and coastal areas than in summer and autumn and inland areas. Climate zones move towards the north obviously. North tropical zone is expanding, south subtropical zone is reducing and central subtropical zone is relatively stable. Under the global climate warming, characteristics of climate warming in Guangdong were influenced by atmosphere general circulation, sea surface temperature and human activities etc.
文摘[ Objective] The research aimed to study climatic zoning of tea tree cultivation in Hanzhong. [Method] Based on climate data at 11 meteorological observatories of Hanzhong during 1971 -2010, selecting annual average extreme minimum temperature, annual average temperature, accumulative temperature ≥10 ℃ and annual rainfall as climatic zoning factors, regression model between zoning factors and geographic information was established, and comprehensive climatic zoning indicator of tea tree cultivation in Hanzhong was determined. [ Result] Tea tree cultivation in Hanzhong was divided into suitable, more suitable and unsuitable planting zones by using critical value of climatic zoning. [ Conclusion] The research could provide scientific basis for reasonable planning layout and sustainable development of tea tree in the whole city.
基金the Slovak Research and Development Agency for the financial support via Project No.APVV-0098-12“Analysis,modelling and evaluation of agroecosystem services”Project No.APVV-15-0160“Elimination of degradation processes in soil by biodiversity restoring”.
文摘For analysis and evaluation of potential of agroecosystem (arable land and grassland) services (provisioning, regulating and cultural) in Slovakia we have created a mapping unit combining these input layers: slope topography, soil texture and landuse in four climatic regions. Evaluated potential of agroecosystem services was categorised into five categories (very low, low, medium, high and very high). Our results show that climate has the most significant impact on agroecosystem services. Warm, dry lowland region has a higher potential of provisioning services, regulation of water regime, filtration of pollutants and control of soil erosion in comparison to moderately warm and cold regions. In moderate cold region, more than 90% of the total area of arable land has low potential of water regime regulation and cleaning potential (immobilization of risk elements). In the moderate warm climatic region, there is a high share of categories of low and moderate potential of provisioning services and low and moderate potential of water regime regulation. Majority of the total area of warm climatic region belongs to the categories of moderate to high potential of provisioning services and high potential of regulation of water regime. In this climatic zone low potential categories of risk elements immobilization are present in more than 65% of the arable land total area. On the other hand, in very warm climatic zone, more than 89% of the total area of arable land belongs to the category with a very high cleaning (buffering) potential. Potential of natural conditions for recreation is higher only in moderate cold and moderate warm climatic zones with a higher proportion of area of grassland agroecosystems and protected areas NATURA 2000. Moreover, the methodology developed in this paper is replicable and could be applied by planners in the case that they are proficient in geographical information systems.
基金Supported by the National Natural Science Foundation of China(42171337 and 42222503)。
文摘Based on the building height and density data on a 100-m resolution,hourly 2-m temperature and humidity data at83 automatic weather stations,and gridded local climate zone(LCZ)data on a 120-m resolution in urban Beijing in2020,this study first employs the semivariogram combined with building parameters to calculate spatial correlations and has identified an LCZ grid resolution of 500 m suitable for best usage of the available observation data.Then,how the spatially heterogeneous LCZs affect and contribute to the canopy urban heat island intensity(UHII)and urban dry island intensity(UDII)are quantitatively investigated.It is found that UHII is high in winter and low in summer with a unimodal diurnal variation while UDI is low in winter but high in summer with a bimodal diurnal variation.The LCZ with compact mid-rise(open high-rise)buildings exhibits the highest UHII(UDII),followed by the compact high-rise(compact low-rise),while the LCZ of scattered trees presents both the lowest UHII and the lowest UDII.The most significant difference in the UHII(UDII)among the nine LCZ types in the urban area of Beijing is2.62℃(1.1 g kg^(-1)).Area-weighted averaging analysis reveals that the open mid-rise LCZ is the most significant contributor to the UHII(UDII),immediately followed by compact mid-rise(open low-rise),with the least contribution from bare rock or paved(scattered trees).The results also indicate that beyond the intrinsic physical properties of the LCZs of a city,their area proportions cannot be overlooked in evaluating their impact on the UHI and UDI.These quantitatively findings could help urban planners to create a livable urban climate and environment by adjusting the relevant land use.
基金Supported by the Science and Technology Research Project of Shandong Meteorological Bureau(2022SDQN17).
文摘Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal, annual and spatial variation characteristics of urban heat island effect in Weihai City in the past 10 years. The results showed that in recent 10 years, the average urban heat island intensity was 1.24 ℃, showing a gradual weakening trend of -0.169 3 ℃/10 a;the summer average heat island intensity was 0.86 ℃, showing a gradual weakening trend of -0.047 5 ℃/10 a. The heat island intensity had obvious diurnal variation characteristics, that is, "it was weak in the day and strong at night". In terms of seasonal variation, heat island effect was the weakest in summer, stronger in spring and autumn, and the strongest in winter. The diurnal, seasonal and annual changes of heat island intensity showed a reverse trend to those of temperature. The high-value area of urban heat island was highly consistent with human residential activity areas and industrial and commercial intensive areas, and the extension trend of heat island intensity was the same as the direction of urban development and construction. The "cold island phenomenon" in some offshore areas was related to the geographical location, terrain and the southeast monsoon trend in summer. The adverse effects of urban heat island effect can be reduced by optimizing the types and distribution of vegetation communities, rationally planning and constructing urban water body, promoting green building materials and adjusting shape design, etc.
基金This work was funded by the Natural Science Foundation of Shandong Province(ZR2021ME199,ZR2021ME237)the Support Plan for Outstanding Youth Innovation Team in Colleges and Universities of Shandong Province(2019KJG005).This work was also supported by the Plan of Introduction and Cultivation for Young Innovative Talents in Colleges and Universities of Shandong Province,and Funding for Domestic Visiting Scholars at Shandong Jianzhu University.
文摘A radiant floor cooling system(RFCS)is a high-comfort and low energy consumption system suitable for residential buildings.Radiant floor systems usually work with fresh air,and their operating performance is affected by climatic conditions.Indoor and outdoor environmental disturbances and the system’s control strategy affect the indoor thermal comfort and energy efficiency of the system.Firstly,a multi-story residential building model was established in this study.Transient system simulation program was used to study the operation dynamics of three control strategies of the RFCS based on the calibrated model.Then,the performance of the control strategies in five climate zones in China were compared using multi-criteria decision-making in combination.The results show that control strategy has a negligible effect on condensation risk,but the thermal comfort and economic performance differ for different control strategies.The adaptability of different control strategies varies in different climate zones based on the consideration of multiple factors.The performance of the direct-ground cooling source system is better in Hot summer and warm winter zone.The variable air volume control strategy scores higher in Serve cold and Temperate zones,and the hours exceeding thermal comfort account for less than 3%of the total simulation period.Therefore,it is suggested to choose the RFCS control strategy for residential buildings according to the climate zone characteristics,to increase the energy savings.Our results provide a reliable reference for implementing RFCSs in residential buildings.
文摘Background Previous studies provided some evidence of meteorological factors influence seasonal influenza transmission patterns varying across regions and latitudes. However, research on seasonal influenza activities based on climate zones are still in lack. This study aims to utilize the ecological-based Koppen Geiger climate zones classification system to compare the spatial and temporal epidemiological characteristics of seasonal influenza in Chinese mainland and assess the feasibility of developing an early warning system.Methods Weekly influenza cases number from 2014 to 2019 at the county and city level were sourced from China National Notifiable Infectious Disease Report Information System. Epidemic temporal indices, time series seasonality decomposition, spatial modelling theories including Moran’s/ and local indicators of spatial association were applied to identify the spatial and temporal patterns of influenza transmission.Results All climate zones had peaks in Winter-Spring season. Arid, desert, cold (BWk) showed up the first peak. Only Tropical, savannah (Aw) and Temperate, dry winter with hot summer (Cwa) zones had unique summer peak. Temperate, no dry season and hot summer (Cfa) zone had highest average incidence rate (IR) at 1.047/100,000. The Global Moran’s/ showed that average IR had significant clustered trend (z = 53.69,P < 0.001), with local Moran’s/ identified high-high cluster in Cfa and Cwa. IR differed among three age groups between climate zones (0-14 years old:F = 26.80,P < 0.001;15-64 years old:F = 25.04,P < 0.001;Above 65 years old:F = 5.27,P < 0.001). Age group 0-14 years had highest average IR in Cwa and Cfa (IR= 6.23 and 6.21) with unique dual peaks in winter and spring season showed by seasonality decomposition.Conclusions Seasonal influenza exhibited distinct spatial and temporal patterns in different climate zones. Seasonal influenza primarily emerged in BWk, subsequently in Cfa and Cwa. Cfa, Cwa and BSk pose high risk for seasonal influenza epidemics. The research finds will provide scientific evidence for developing seasonal influenza early warning system based on climate zones.
基金This research was jointly supported by the National Natural Science Foundation of China(41991284)the Science and Technology Project of Education Department of Jiangxi province(GJJ2201249).
文摘Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied previously.We used an ensemble of a regional climate model(RegCM4)projections to assess future changes in surface air temperature,precipitation and Köppen-Trewartha(K-T)climate types in Northern Asia under the 1.5-4℃global warming targets.RegCM4 is driven by five CMIP5 global models over an East Asia domain at a grid spacing of 25 km.Validation of the present day(1986-2005)simulations shows that the ensembles of RegCM4(ensR)and driving GCMs(ensG)reproduce the major characters of the observed temperature,precipitation and K-T climate zones reasonably well.Greater and more realistic spatial detail is found in RegCM4 compared to the driving GCMs.A general warming and overall increases in precipitation are projected over the region,with these changes being more pronounced at higher warming levels.The projected warming by ensR shows different spatial patterns,and is in general lower,compared to ensG in most months of the year,while the percentage increases of precipitation are maximum during the cold months.The future changes in K-T climate zones are characterized by a substantial expansion of Dc(temperature oceanic)and retreat of Ec(sub-arctic continental)over the region,reaching∼20%under the 4℃warming level.The most notable change in climate types in ensR is found over Japan(∼60%),followed by Southern Siberia,Mongolia,and the Korean Peninsula(∼40%).The largest change in the K-T climate types is found when increasing from 2 to 3℃.The results will help to better assess the impacts of climate change and in implementation of appropriate adaptation measures over the region.
基金supported by the faculty of architecture,Khon Kaen University.
文摘This study focuses on carbon emissions of the building sector in relation to local climate zone(LCZ)classification,concentrating on two major parts.First,we estimated carbon emissions in the building sector,which were cal-culated for weekdays and weekends real-time daily energy consumption patterns.The estimations were divided into direct(from petroleum products consumption)and indirect emissions(from electricity consumption).Sec-ond,we examined urban carbon emissions mapping in relation to LCZ.Bangkok Metropolitan Administration(BMA)was used as the case study and 2016 as the base year for examination.The results illustrate that indirect emissions in Bangkok can be up to ten times higher than direct emissions.The analysis indicates that LCZ,such as compact high-rise,large low-rise,light industry,and warehouse zones had a relatively higher carbon emission intensity than others.Additionally,we identified that the compact high-rise zone has the highest indirect emission intensity,while the light industry and warehouse zone have the greatest direct emission intensity.These results provide insights into the dynamics of carbon emission characteristics in the building sector and the methodology purported here can be used to support low carbon city planning and policymaking in Bangkok.
基金supported by the Special Foundation of National Science & Technology Supporting Plan (2011BAD29B09)the National Natural Science Foundation of China (31172039)+2 种基金the ‘111’ Project from the Ministry of Edu- cation and the State Administration of Foreign Experts Affairs (B12007)the Supporting Project of Young Technology Nova of Shaanxi Province (2010KJXX-04)the Supporting Plan of Young Elites and basic operational cost of research from Northwest A&F University
文摘The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China (NW) dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years (1981-2010) from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique (FC), an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs.
基金supported by National Key Basic Research Program of "973" Project (Grant No.2012CB822003,2006CB701401-03)the Project of the National Natural Science Foundation of China (Grant No.41072083)the Cultivating Program of Young and Middle-aged Backbone Teachers of Chengdu University of Technology
文摘The Cretaceous was one of the most remarkable 'greenhouse' climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial scale paleoclimatic reconstruction, which has a higher time resolution based upon continental sediments in China, is rarely found. This study presents paleoclimate reconstruction for the six time periods of the Early Cretaceous in China by employing continental climate-indicative sediments, including calcareous deposits, coal, oil shale, gypsum, halite, desert sedimentary systems, ferruginous deposits and laterite, copper-bearing deposits, limestone and dolomite. Based on the distribution of the association of climate-indicative sediments and the influences of paleotopography and orogenic belts (or important structural belts) on climate, seven climatic zones have been identified: 1) a warm and humid zone; 2) a warm and humid-warm and arid zone; 3) a warm and arid zone; 4) an arid and hot zone; 5) the Tibet hot and humid zone; 6) a hot and arid-semiarid zone; and 7) a hot and humid-hot and arid one. It is found that the Early Cretaceous climatic zones of China were nearly latitudinally distributed from northwest to southeast. The arid- hot climatic zone expanded in the Aptian, suggesting that a hotter and drier climate prevailed in later period of the Early Cretaceous. Conversely, the humid climatic zone expanded in the Albian, indicating that a wetter climate appeared at the end of the Early Cretaceous. The overall distribution pattern of the seven climatic zones indicates that a hot-warm and arid climate was predominant in China; this coincides with a global 'greenhouse climate' background. However, palaeogeographic features and specific geologic events, such as the existence and disappearance of the eastern high plateau, and the uplift and denudation of Yinshan, Yanshan, Tianshan, Qinling and Dabie Mountains, led to distinctive regional climatic features of the Cretaceous in China.