By analyzing climate condition during growth period of tobacco in Yuxian,scientific and reasonable production management measures are made. For meteorological disasters during growth period of tobacco, corresponding d...By analyzing climate condition during growth period of tobacco in Yuxian,scientific and reasonable production management measures are made. For meteorological disasters during growth period of tobacco, corresponding defense measures are put forward. It could provide the basis for further conducting meteorological service of tobacco, and the meteorological guide for farmers improving tobacco planting quality and decreasing the loss caused by the disastrous weather.展开更多
Climate-responsive building design holds immense potential for enhancing comfort,energy efficiency,and environmental sustainability.However,many social,cultural,and economic obstacles might prevent the wide adoption o...Climate-responsive building design holds immense potential for enhancing comfort,energy efficiency,and environmental sustainability.However,many social,cultural,and economic obstacles might prevent the wide adoption of designing climate-adapted buildings.One of these obstacles can be removed by enabling practitioners to easily access,visualize and analyze local climate data.The CBE Clima Tool(Clima)is a free and open-source web application that offers easy access to publicly available weather files and has been created for building energy simulation and design.It provides a series of interactive visualizations of the variables contained in the EnergyPlus Weather Files and several derived ones like the UTCI or the adaptive comfort indices.It is aimed at students,educators,and practitioners in the architecture and engineering fields.Since its inception,Clima’s user base has exhibited robust growth,attracting over 25,000 unique users annually from across 70 countries.Our tool is poised to revolutionize climate-adaptive building design,transcending geographical boundaries and fostering innovation in the architecture and engineering fields.展开更多
Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 ...Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.展开更多
Correlation analysis as used by meteorologists and oceanographers is a tool for the analysisof the spacial or temporal variability of physical fields. In his notes, Dr. Hasselmann pro-posed to combine correlation anal...Correlation analysis as used by meteorologists and oceanographers is a tool for the analysisof the spacial or temporal variability of physical fields. In his notes, Dr. Hasselmann pro-posed to combine correlation analysis and linear regression analysis in climate prediction re-search. The main idea is to decompose the physical field into its principal oscillation patterns.展开更多
Based on the meteorological data in Fushun region from 1961 to 2008,the characteristics of climate change in Fushun City were concluded through statistical analysis.The results showed that the temperature increased,wh...Based on the meteorological data in Fushun region from 1961 to 2008,the characteristics of climate change in Fushun City were concluded through statistical analysis.The results showed that the temperature increased,while there was a decrease in precipitation and sunlight.Moreover,climate change had both positive and negative influences on agricultural production and crop growth,so we should take effective measures to make use of effective accumulated temperature.展开更多
Five pollen zones are identified in Yangmu peatland of Mishan region located at 45o34扤, 132o23扙 through sporo-pollen analysis. The changing process of paleovegetation and paleoclimate was obtained. Warm-inclined bro...Five pollen zones are identified in Yangmu peatland of Mishan region located at 45o34扤, 132o23扙 through sporo-pollen analysis. The changing process of paleovegetation and paleoclimate was obtained. Warm-inclined broad-leaved forest predominated in the environment of warm climate with a little dry 3400 yr BP. Deciduous broad-leaved and coniferous mixed forests predominated, in which Pinus, Picea and Abies were main species, together with wet meadow in the environment of cool and humid climate during 3400-1940 yr BP. Deciduous broad-leaved and coniferous mixed forests predominated in the dry and warm climate environment 1940-1090 yr BP. Broad-leaved forest was predominant, and the climate was warm and humid 1090-545 yr BP. Marsh meadow predominated when the climate changed to cool and dry 545 yr BP. The composition of the upper part of the 143-125 cm of the peat profile presented the cold period in the early Christian era through mutual identification between the records of historical material such as spores and pollens, susceptibility, organic matter and archaeological studies. The composition of the parts of 125-85 cm and 85-38 cm presented the warm climate in the Northern and Southern Dynasty and Sui and Tang dynasties. Since 3400 yr BP because of the frequent human activities in Mishan region, the amount of cultural relics in the Sui and Tang dynasties increased, which indicated that the ancients took much more woods from the forests in the warm climate environment.展开更多
The preliminary analysis of climatic variation in China during the last 39 years has been made in this paper. The results show that although the global climate is getting warmer, some parts of China are cooling. The w...The preliminary analysis of climatic variation in China during the last 39 years has been made in this paper. The results show that although the global climate is getting warmer, some parts of China are cooling. The warming only occurs in Northeast, North and the west part of Northwest China while the areas between about 35°N and Nanling Mountain, east of the Tibetan Plateau in China are getting cooler. The cooling centers are located in Sichuan, the south part of Shaanxi and the north part of Yunnan respectively. According to the theory of greenhouse effect, there are much precipitation at low and high latitudes and less precipitation in middle latitude. However, the precipitation in the most parts of China has been decreased, especially in North and Northwest China.展开更多
Previous studies have found amplified warming over Europe-West Asia and Northeast Asia in summer since the mid- 1990s relative to elsewhere on the Eurasian continent, but the cause of the amplification in these two re...Previous studies have found amplified warming over Europe-West Asia and Northeast Asia in summer since the mid- 1990s relative to elsewhere on the Eurasian continent, but the cause of the amplification in these two regions remains unclear. In this study, we compared the individual contributions of influential factors for amplified warming over these two regions through a quantitative diagnostic analysis based on CFRAM (climate feedback-response analysis method). The changes in surface air temperature are decomposed into the partial changes due to radiative processes (including CO2 concentration, incident solar radiation at the top of the atmosphere, surface albedo, water vapor content, ozone concentration, and clouds) and non-radiative processes (including surface sensible heat flux, surface latent heat flux, and dynamical processes). Our results suggest that the enhanced warming over these two regions is primarily attributable to changes in the radiative processes, which contributed 0.62 and 0.98 K to the region-averaged warming over Europe-West Asia (1.00 K) and Northeast Asia (1.02 K), respectively. Among the radiative processes, the main drivers were clouds, CO2 concentration, and water vapor content. The cloud term alone contributed to the mean amplitude of warming by 0.40 and 0.85 K in Europe-West Asia and Northeast Asia, respectively. In comparison, the non-radiative processes made a much weaker contribution due to the combined impact of surface sensible heat flux, surface latent heat flux, and dynamical processes, accounting for only 0.38 K for the warming in Europe-West Asia and 0.05 K for the warming in Northeast Asia. The resemblance between the influential factors for the amplified warming in these two separate regions implies a common dynamical origin. Thus, this validates the possibility that they originate from the Silk Road pattern.展开更多
We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and ...We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and DEM. By using harmonic analysis and Shepard inverse distance interpolation,we quantitatively analyzed precipitation observation data at 68 reference weather stations of Zhejiang Province in recent 50 years,and established climatic analysis field of daily precipitation at 1 km grid of Zhejiang Province considering terrain influence. Systemic cross-examination of the method was conducted. Result showed that the established fine climatic field for precipitation could reproduce rapid seasonal evolution characteristics of precipitation induced by monsoon migration and typhoon landing with better quantitative accuracy.展开更多
Based on the 1951-2007 thunderstorms in Jiangsu,a study is conducted for their climate trends,periodicity,spatiotemporal patterns,and the distributions of the first and last days of the thunderstorms at different guar...Based on the 1951-2007 thunderstorms in Jiangsu,a study is conducted for their climate trends,periodicity,spatiotemporal patterns,and the distributions of the first and last days of the thunderstorms at different guarantee rates (GRs) using climate tendency rate,wavelet analysis,and GR for diagnosis.Results suggest that the inter-annual number of thunderstorm days (TSDs) exhibits a decreasing trend in this province.The trend is displayed mainly in the decreasing TSD number in summer and autumn except in spring,when the variation is not significant in the study period.In this province,the TSD number declines by ~2 days per 10 years.On an inter-annual basis,the pronounced positive departures of the number take place chiefly in the early 1960s,the late 1960s to the early-mid-1970s,the late 1980s,and the late 1990s compared with the negative anomalies dominant in the late 1970s to the mid-1980s,the mid-to-late-1990s,and the late 1990s to 2007.There are vast differences in the initial and ending days at diverse GRs in different areas of the province.At 50% GR,the earliest (last) days occur from mid-March to early April (early to late September) while at 80% GR,the initial (last) days are from late March to early May (early to late October).For the distribution of periods,the periods >8-10 years are relatively stable for the entire province.Based on 1951-2007 period analysis,the region north (south) of the Huaihe River experiences TSDs less (more) than normal days in recent years.展开更多
The Ross-Amundsen sector is experiencing an accelerating warming trend and a more intensive advective influx of marine air streams.As a result,massive surface melting events of the ice shelf are occurring more frequen...The Ross-Amundsen sector is experiencing an accelerating warming trend and a more intensive advective influx of marine air streams.As a result,massive surface melting events of the ice shelf are occurring more frequently,which puts the West Antarctica Ice Sheet at greater risk of degradation.This study shows the connection between surface melting and the prominent intrusion of warm and humid air flows from lower latitudes.By applying the Climate Feedback-Response Analysis Method(CFRAM),the temporal surge of the downward longwave(LW)fluxes over the surface of the Ross Ice Shelf(RIS)and adjacent regions are identified for four historically massive RIS surface melting events.The melting events are decomposed to identify which physical mechanisms are the main contributors.We found that intrusions of warm and humid airflow from lower latitudes are conducive to warm air temperature and water vapor anomalies,as well as cloud development.These changes exert a combined impact on the abnormal enhancement of the downward LW surface radiative fluxes,significantly contributing to surface warming and the resultant massive melting of ice.展开更多
The seasonal phase-locking feature of the Indian Ocean Dipole(IOD)is well documented.However,the seasonality ten-dency of sea surface temperature anomalies(SSTAs)during the development of the IOD has not been widely i...The seasonal phase-locking feature of the Indian Ocean Dipole(IOD)is well documented.However,the seasonality ten-dency of sea surface temperature anomalies(SSTAs)during the development of the IOD has not been widely investigated.The SSTA tendencies over the two centers of the IOD peak in September-October-November are of different monthly amplitudes.The SSTA tendency over the west pole is small before June-July-August but dramatically increases in July-August-September.Meanwhile,the SSTA tendency over the east pole gradually increases before June-July-August and decreases since then.The growth rate attribution of the SSTAs is achieved by examining the roles of radiative and non-radiative air-sea coupled thermodynamic processes through the climate feedback-response analysis method(CFRAM).The CFRAM results indicate that oceanic dynamic processes largely contribute to the total SSTA tendency for initiating and fueling the IOD SSTAs,similar to previous studies.However,these results cannot ex-plain the monthly amplitudes of SSTA tendency.Four negative feedback processes(cloud radiative feedback,atmospheric dynamic processes,surface sensible,and latent heat flux)together play a damping role opposite to the SSTA tendency.Nevertheless,the sea surface temperature-water vapor feedback shows positive feedback.Specifically,variations in SSTAs can change water vapor con-centrations through evaporation,resulting in anomalous longwave radiation that amplifies the initial SSTAs through positive feedback.The effect of water vapor feedback is well in-phase with the monthly amplitudes of SSTA tendency,suggesting that the water vapor feedback might modulate the seasonally dependent SSTA tendency during the development of the IOD.展开更多
We performed long-term wind-wave hindcast in the Yellow Sea and the Bohai Sea from the year 1988 to 2002, and then analyzed the regional wave climate. Comparisons between model results and satellite data are generally...We performed long-term wind-wave hindcast in the Yellow Sea and the Bohai Sea from the year 1988 to 2002, and then analyzed the regional wave climate. Comparisons between model results and satellite data are generally consistent on monthly mean significant wave height. Then we discuss the temporal and spatial characteristics of the climatological monthly mean significant wave heights and mean wave periods. The climatologically spatial patterns are observed as increasing from northwest to southeast and from offshore to deep-water area for both significant wave height and mean wave period, and the patterns are highly related to the wind forcing and local topography. Seasonal variations of wave parameters are also significant. Furthermore, we compute the extreme values of wind and significant wave height using statistical methods. Results reveal the spatial patterns of N-year return significant wave height in the Yellow Sea and the Bohai Sea, and we discuss the relationship between extreme values of significant wave height and wind forcing.展开更多
Spatio-temporal variations of vegetation phenology, e.g. start of green-up season(SOS) and end of vegetation season(EOS), serve as important indicators of ecosystems. Routinely processed products from remotely sen...Spatio-temporal variations of vegetation phenology, e.g. start of green-up season(SOS) and end of vegetation season(EOS), serve as important indicators of ecosystems. Routinely processed products from remotely sensed imagery, such as the normalized difference vegetation index(NDVI), can be used to map such variations. A remote sensing approach to tracing vegetation phenology was demonstrated here in application to the Inner Mongolia grassland, China. SOS and EOS mapping at regional and vegetation type(meadow steppe, typical steppe, desert steppe and steppe desert) levels using SPOT-VGT NDVI series allows new insights into the grassland ecosystem. The spatial and temporal variability of SOS and EOS during 1998–2012 was highlighted and presented, as were SOS and EOS responses to the monthly climatic fluctuations. Results indicated that SOS and EOS did not exhibit consistent shifts at either regional or vegetation type level; the one exception was the steppe desert, the least productive vegetation cover, which exhibited a progressive earlier SOS and later EOS. Monthly average temperature and precipitation in preseason(February, March and April) imposed most remarkable and negative effects on SOS(except for the non-significant impact of precipitation on that of the meadow steppe), while the climate impact on EOS was found to vary considerably between the vegetation types. Results showed that the spatio-temporal variability of the vegetation phenology of the meadow steppe, typical steppe and desert steppe could be reflected by the monthly thermal and hydrological factors but the progressive earlier SOS and later EOS of the highly degraded steppe desert might be accounted for by non-climate factors only, suggesting that the vegetation growing period in the highly degraded areas of the grassland could be extended possibly by human interventions.展开更多
The seasonal and inter-annual variations of Arctic cyclone are investigated. An automatic cyclone tracking algorithm developed by University of Reading was applied on the basis of European Center for Medium-range Weat...The seasonal and inter-annual variations of Arctic cyclone are investigated. An automatic cyclone tracking algorithm developed by University of Reading was applied on the basis of European Center for Medium-range Weather Forecasts(ECMWF) ERA-interim mean sea level pressure field with 6 h interval for 34 a period. The maximum number of the Arctic cyclones is counted in winter, and the minimum is in spring not in summer.About 50% of Arctic cyclones in summer generated from south of 70°N, moving into the Arctic. The number of Arctic cyclones has large inter-annual and seasonal variabilities, but no significant linear trend is detected for the period 1979–2012. The spatial distribution and linear trends of the Arctic cyclones track density show that the cyclone activity extent is the widest in summer with significant increasing trend in CRU(central Russia)subregion, and the largest track density is in winter with decreasing trend in the same subregion. The linear regressions between the cyclone track density and large-scale indices for the same period and pre-period sea ice area indices show that Arctic cyclone activities are closely linked to large-scale atmospheric circulations, such as Arctic Oscillation(AO), North Atlantic Oscillation(NAO) and Pacific-North American Pattern(PNA). Moreover,the pre-period sea ice area is significantly associated with the cyclone activities in some regions.展开更多
Driven by the increase in CO_(2)concentration,climate models reach a consensus that the large-scale circulation of the South Asian summer monsoon(SASM) becomes weakened but with different magnitudes.This study investi...Driven by the increase in CO_(2)concentration,climate models reach a consensus that the large-scale circulation of the South Asian summer monsoon(SASM) becomes weakened but with different magnitudes.This study investigates the major uncertainty sources of the SASM response to an abrupt quadrupling of CO_(2)(abrupt-4×CO_(2))in 18 models of phase 6 of the Coupled Model Intercomparison Project.The projected weakening of the SASM indicated by both zonal and meridional monsoon circulation indices is closely linked to decreases in the meridional gradient of upper-tropospheric temperature between Eurasia and the Indian Ocean(EUTT-IUTT).A climate feedback-response analysis method is applied to linearly decompose the uncertainty of changes in EUTT-IUTT into the partial changes due to external forcing and internal processes of the earth-atmosphere column.Results show that the uncertainty of changes in EUTT-IUTT is contributed positively by the dominant atmospheric dynamic process,followed by the cloud shortwave radiative effect,and negatively by the surface latent heat flux and cloud longwave radiative effect.Contributions from CO_(2)forcing and other internal processes including albedo and water vapor feedbacks,oceanic heat storage,and sensible heat flux are found to be minor.展开更多
In this study we validate the raw ensemble mean forecasts of the CCCma's GCM2 model against surface temperature and precipitation data obtained from 160 Chinese stations.It is found that despite the lagre biases,t...In this study we validate the raw ensemble mean forecasts of the CCCma's GCM2 model against surface temperature and precipitation data obtained from 160 Chinese stations.It is found that despite the lagre biases,the model was able to produce seasonal anomalies that have properties that are reasonably close to those that are observed.This anomaly is the quantity of interest when forecasting seasonal climatic conditions.The root mean squared difference(RMSD) between the forecast and observed anomaly leads us to be modestly optimistic about the prospects for using dynamical models to forecast the interannual variability of some meteorological elements. The correlation analysis of the forecast and observation also supports the result given by the RMSD analysis and provides a tool for identify the forecast confidence level in various regions,展开更多
文摘By analyzing climate condition during growth period of tobacco in Yuxian,scientific and reasonable production management measures are made. For meteorological disasters during growth period of tobacco, corresponding defense measures are put forward. It could provide the basis for further conducting meteorological service of tobacco, and the meteorological guide for farmers improving tobacco planting quality and decreasing the loss caused by the disastrous weather.
基金We would like to acknowledge the work of the authors who contributed to the development of the CBE Clima Tool(https://github.com/Center For The Built Environment/clima/graphs/contributors).This research has been supported by the Center for the Built Environment at the University of California Berkeley and the Republic of Singapore’s National Research Foundation through a grant to the Berkeley Education Alliance for Research in Singapore(BEARS)for the Singapore-Berkeley Building Efficiency and Sustainability in the Tropics(SinBerBEST)Program.
文摘Climate-responsive building design holds immense potential for enhancing comfort,energy efficiency,and environmental sustainability.However,many social,cultural,and economic obstacles might prevent the wide adoption of designing climate-adapted buildings.One of these obstacles can be removed by enabling practitioners to easily access,visualize and analyze local climate data.The CBE Clima Tool(Clima)is a free and open-source web application that offers easy access to publicly available weather files and has been created for building energy simulation and design.It provides a series of interactive visualizations of the variables contained in the EnergyPlus Weather Files and several derived ones like the UTCI or the adaptive comfort indices.It is aimed at students,educators,and practitioners in the architecture and engineering fields.Since its inception,Clima’s user base has exhibited robust growth,attracting over 25,000 unique users annually from across 70 countries.Our tool is poised to revolutionize climate-adaptive building design,transcending geographical boundaries and fostering innovation in the architecture and engineering fields.
基金supported by the National Key Research and Development Program of China[grant number 2023YFC3206001]the Three Gorges Project Comprehensive Monitoring Program for Operational Safety[grant number SK2023019]which funded by the Ministry of Water Resources of China.
文摘Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.
文摘Correlation analysis as used by meteorologists and oceanographers is a tool for the analysisof the spacial or temporal variability of physical fields. In his notes, Dr. Hasselmann pro-posed to combine correlation analysis and linear regression analysis in climate prediction re-search. The main idea is to decompose the physical field into its principal oscillation patterns.
基金Supported by Government of Fushun City(20071209)
文摘Based on the meteorological data in Fushun region from 1961 to 2008,the characteristics of climate change in Fushun City were concluded through statistical analysis.The results showed that the temperature increased,while there was a decrease in precipitation and sunlight.Moreover,climate change had both positive and negative influences on agricultural production and crop growth,so we should take effective measures to make use of effective accumulated temperature.
基金National Natural Science Foundation of China No.49571073
文摘Five pollen zones are identified in Yangmu peatland of Mishan region located at 45o34扤, 132o23扙 through sporo-pollen analysis. The changing process of paleovegetation and paleoclimate was obtained. Warm-inclined broad-leaved forest predominated in the environment of warm climate with a little dry 3400 yr BP. Deciduous broad-leaved and coniferous mixed forests predominated, in which Pinus, Picea and Abies were main species, together with wet meadow in the environment of cool and humid climate during 3400-1940 yr BP. Deciduous broad-leaved and coniferous mixed forests predominated in the dry and warm climate environment 1940-1090 yr BP. Broad-leaved forest was predominant, and the climate was warm and humid 1090-545 yr BP. Marsh meadow predominated when the climate changed to cool and dry 545 yr BP. The composition of the upper part of the 143-125 cm of the peat profile presented the cold period in the early Christian era through mutual identification between the records of historical material such as spores and pollens, susceptibility, organic matter and archaeological studies. The composition of the parts of 125-85 cm and 85-38 cm presented the warm climate in the Northern and Southern Dynasty and Sui and Tang dynasties. Since 3400 yr BP because of the frequent human activities in Mishan region, the amount of cultural relics in the Sui and Tang dynasties increased, which indicated that the ancients took much more woods from the forests in the warm climate environment.
基金This work is supported by National Environment and Protect Agency under Program 891205
文摘The preliminary analysis of climatic variation in China during the last 39 years has been made in this paper. The results show that although the global climate is getting warmer, some parts of China are cooling. The warming only occurs in Northeast, North and the west part of Northwest China while the areas between about 35°N and Nanling Mountain, east of the Tibetan Plateau in China are getting cooler. The cooling centers are located in Sichuan, the south part of Shaanxi and the north part of Yunnan respectively. According to the theory of greenhouse effect, there are much precipitation at low and high latitudes and less precipitation in middle latitude. However, the precipitation in the most parts of China has been decreased, especially in North and Northwest China.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0606403 and 2015CB453202)the National Natural Science Foundation of China(Grant Nos.41790473 and 41421004)
文摘Previous studies have found amplified warming over Europe-West Asia and Northeast Asia in summer since the mid- 1990s relative to elsewhere on the Eurasian continent, but the cause of the amplification in these two regions remains unclear. In this study, we compared the individual contributions of influential factors for amplified warming over these two regions through a quantitative diagnostic analysis based on CFRAM (climate feedback-response analysis method). The changes in surface air temperature are decomposed into the partial changes due to radiative processes (including CO2 concentration, incident solar radiation at the top of the atmosphere, surface albedo, water vapor content, ozone concentration, and clouds) and non-radiative processes (including surface sensible heat flux, surface latent heat flux, and dynamical processes). Our results suggest that the enhanced warming over these two regions is primarily attributable to changes in the radiative processes, which contributed 0.62 and 0.98 K to the region-averaged warming over Europe-West Asia (1.00 K) and Northeast Asia (1.02 K), respectively. Among the radiative processes, the main drivers were clouds, CO2 concentration, and water vapor content. The cloud term alone contributed to the mean amplitude of warming by 0.40 and 0.85 K in Europe-West Asia and Northeast Asia, respectively. In comparison, the non-radiative processes made a much weaker contribution due to the combined impact of surface sensible heat flux, surface latent heat flux, and dynamical processes, accounting for only 0.38 K for the warming in Europe-West Asia and 0.05 K for the warming in Northeast Asia. The resemblance between the influential factors for the amplified warming in these two separate regions implies a common dynamical origin. Thus, this validates the possibility that they originate from the Silk Road pattern.
基金Supported by Nonprofit Technology Application and Research Item of 2011,Zhejiang Science and Technology Department,China(2011C33G1610011)
文摘We successfully developed a set of technical methods constructing fine climatic analysis field for regional precipitation considering terrain influence based on PRISM monthly climatic precipitation analysis field and DEM. By using harmonic analysis and Shepard inverse distance interpolation,we quantitatively analyzed precipitation observation data at 68 reference weather stations of Zhejiang Province in recent 50 years,and established climatic analysis field of daily precipitation at 1 km grid of Zhejiang Province considering terrain influence. Systemic cross-examination of the method was conducted. Result showed that the established fine climatic field for precipitation could reproduce rapid seasonal evolution characteristics of precipitation induced by monsoon migration and typhoon landing with better quantitative accuracy.
基金Social Development Program of Jiangsu Science and Technology (BS2007088)
文摘Based on the 1951-2007 thunderstorms in Jiangsu,a study is conducted for their climate trends,periodicity,spatiotemporal patterns,and the distributions of the first and last days of the thunderstorms at different guarantee rates (GRs) using climate tendency rate,wavelet analysis,and GR for diagnosis.Results suggest that the inter-annual number of thunderstorm days (TSDs) exhibits a decreasing trend in this province.The trend is displayed mainly in the decreasing TSD number in summer and autumn except in spring,when the variation is not significant in the study period.In this province,the TSD number declines by ~2 days per 10 years.On an inter-annual basis,the pronounced positive departures of the number take place chiefly in the early 1960s,the late 1960s to the early-mid-1970s,the late 1980s,and the late 1990s compared with the negative anomalies dominant in the late 1970s to the mid-1980s,the mid-to-late-1990s,and the late 1990s to 2007.There are vast differences in the initial and ending days at diverse GRs in different areas of the province.At 50% GR,the earliest (last) days occur from mid-March to early April (early to late September) while at 80% GR,the initial (last) days are from late March to early May (early to late October).For the distribution of periods,the periods >8-10 years are relatively stable for the entire province.Based on 1951-2007 period analysis,the region north (south) of the Huaihe River experiences TSDs less (more) than normal days in recent years.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42075028 and 42222502)the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant SML2021SP302)
文摘The Ross-Amundsen sector is experiencing an accelerating warming trend and a more intensive advective influx of marine air streams.As a result,massive surface melting events of the ice shelf are occurring more frequently,which puts the West Antarctica Ice Sheet at greater risk of degradation.This study shows the connection between surface melting and the prominent intrusion of warm and humid air flows from lower latitudes.By applying the Climate Feedback-Response Analysis Method(CFRAM),the temporal surge of the downward longwave(LW)fluxes over the surface of the Ross Ice Shelf(RIS)and adjacent regions are identified for four historically massive RIS surface melting events.The melting events are decomposed to identify which physical mechanisms are the main contributors.We found that intrusions of warm and humid airflow from lower latitudes are conducive to warm air temperature and water vapor anomalies,as well as cloud development.These changes exert a combined impact on the abnormal enhancement of the downward LW surface radiative fluxes,significantly contributing to surface warming and the resultant massive melting of ice.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(No.2019QZKK0102)the National Natural Science Foundation of China(No.42176026)supported by the National Postdoctoral Program of Innovative Talents(No.BX2021324).
文摘The seasonal phase-locking feature of the Indian Ocean Dipole(IOD)is well documented.However,the seasonality ten-dency of sea surface temperature anomalies(SSTAs)during the development of the IOD has not been widely investigated.The SSTA tendencies over the two centers of the IOD peak in September-October-November are of different monthly amplitudes.The SSTA tendency over the west pole is small before June-July-August but dramatically increases in July-August-September.Meanwhile,the SSTA tendency over the east pole gradually increases before June-July-August and decreases since then.The growth rate attribution of the SSTAs is achieved by examining the roles of radiative and non-radiative air-sea coupled thermodynamic processes through the climate feedback-response analysis method(CFRAM).The CFRAM results indicate that oceanic dynamic processes largely contribute to the total SSTA tendency for initiating and fueling the IOD SSTAs,similar to previous studies.However,these results cannot ex-plain the monthly amplitudes of SSTA tendency.Four negative feedback processes(cloud radiative feedback,atmospheric dynamic processes,surface sensible,and latent heat flux)together play a damping role opposite to the SSTA tendency.Nevertheless,the sea surface temperature-water vapor feedback shows positive feedback.Specifically,variations in SSTAs can change water vapor con-centrations through evaporation,resulting in anomalous longwave radiation that amplifies the initial SSTAs through positive feedback.The effect of water vapor feedback is well in-phase with the monthly amplitudes of SSTA tendency,suggesting that the water vapor feedback might modulate the seasonally dependent SSTA tendency during the development of the IOD.
基金The National Natural Science Foundation of China under contract Nos 41476021 and 41321004the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11010104the project of Indo-Pacific Ocean Environment Variation and Air-sea Interaction under contract No.GASI-IPOVAI-04
文摘We performed long-term wind-wave hindcast in the Yellow Sea and the Bohai Sea from the year 1988 to 2002, and then analyzed the regional wave climate. Comparisons between model results and satellite data are generally consistent on monthly mean significant wave height. Then we discuss the temporal and spatial characteristics of the climatological monthly mean significant wave heights and mean wave periods. The climatologically spatial patterns are observed as increasing from northwest to southeast and from offshore to deep-water area for both significant wave height and mean wave period, and the patterns are highly related to the wind forcing and local topography. Seasonal variations of wave parameters are also significant. Furthermore, we compute the extreme values of wind and significant wave height using statistical methods. Results reveal the spatial patterns of N-year return significant wave height in the Yellow Sea and the Bohai Sea, and we discuss the relationship between extreme values of significant wave height and wind forcing.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050402)the Key Laboratory for Geographic State Monitoring of the National Administration of Surveying, Mapping and Geoinformation (2014-04)the National Natural Science Foundation of China (41071249, 41371371)
文摘Spatio-temporal variations of vegetation phenology, e.g. start of green-up season(SOS) and end of vegetation season(EOS), serve as important indicators of ecosystems. Routinely processed products from remotely sensed imagery, such as the normalized difference vegetation index(NDVI), can be used to map such variations. A remote sensing approach to tracing vegetation phenology was demonstrated here in application to the Inner Mongolia grassland, China. SOS and EOS mapping at regional and vegetation type(meadow steppe, typical steppe, desert steppe and steppe desert) levels using SPOT-VGT NDVI series allows new insights into the grassland ecosystem. The spatial and temporal variability of SOS and EOS during 1998–2012 was highlighted and presented, as were SOS and EOS responses to the monthly climatic fluctuations. Results indicated that SOS and EOS did not exhibit consistent shifts at either regional or vegetation type level; the one exception was the steppe desert, the least productive vegetation cover, which exhibited a progressive earlier SOS and later EOS. Monthly average temperature and precipitation in preseason(February, March and April) imposed most remarkable and negative effects on SOS(except for the non-significant impact of precipitation on that of the meadow steppe), while the climate impact on EOS was found to vary considerably between the vegetation types. Results showed that the spatio-temporal variability of the vegetation phenology of the meadow steppe, typical steppe and desert steppe could be reflected by the monthly thermal and hydrological factors but the progressive earlier SOS and later EOS of the highly degraded steppe desert might be accounted for by non-climate factors only, suggesting that the vegetation growing period in the highly degraded areas of the grassland could be extended possibly by human interventions.
基金The Chinese Polar Environment Comprehensive Investigation and Assessment Programmes under contract No.2016-04-03the National Key Research and Development Program of China under contract No.2016YFC1402701
文摘The seasonal and inter-annual variations of Arctic cyclone are investigated. An automatic cyclone tracking algorithm developed by University of Reading was applied on the basis of European Center for Medium-range Weather Forecasts(ECMWF) ERA-interim mean sea level pressure field with 6 h interval for 34 a period. The maximum number of the Arctic cyclones is counted in winter, and the minimum is in spring not in summer.About 50% of Arctic cyclones in summer generated from south of 70°N, moving into the Arctic. The number of Arctic cyclones has large inter-annual and seasonal variabilities, but no significant linear trend is detected for the period 1979–2012. The spatial distribution and linear trends of the Arctic cyclones track density show that the cyclone activity extent is the widest in summer with significant increasing trend in CRU(central Russia)subregion, and the largest track density is in winter with decreasing trend in the same subregion. The linear regressions between the cyclone track density and large-scale indices for the same period and pre-period sea ice area indices show that Arctic cyclone activities are closely linked to large-scale atmospheric circulations, such as Arctic Oscillation(AO), North Atlantic Oscillation(NAO) and Pacific-North American Pattern(PNA). Moreover,the pre-period sea ice area is significantly associated with the cyclone activities in some regions.
基金jointly supported by the National Natural Science Foundation of China [grant numbers 4208810141911540470+3 种基金42075028]the Guangdong Major Project of Basic and Applied Basic Research [grant number 2020B0301030004]the Natural Science Foundation of Guangdong Province of China [grant number 2018A0303130268]the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies [grant number2020B1212060025]。
文摘Driven by the increase in CO_(2)concentration,climate models reach a consensus that the large-scale circulation of the South Asian summer monsoon(SASM) becomes weakened but with different magnitudes.This study investigates the major uncertainty sources of the SASM response to an abrupt quadrupling of CO_(2)(abrupt-4×CO_(2))in 18 models of phase 6 of the Coupled Model Intercomparison Project.The projected weakening of the SASM indicated by both zonal and meridional monsoon circulation indices is closely linked to decreases in the meridional gradient of upper-tropospheric temperature between Eurasia and the Indian Ocean(EUTT-IUTT).A climate feedback-response analysis method is applied to linearly decompose the uncertainty of changes in EUTT-IUTT into the partial changes due to external forcing and internal processes of the earth-atmosphere column.Results show that the uncertainty of changes in EUTT-IUTT is contributed positively by the dominant atmospheric dynamic process,followed by the cloud shortwave radiative effect,and negatively by the surface latent heat flux and cloud longwave radiative effect.Contributions from CO_(2)forcing and other internal processes including albedo and water vapor feedbacks,oceanic heat storage,and sensible heat flux are found to be minor.
文摘In this study we validate the raw ensemble mean forecasts of the CCCma's GCM2 model against surface temperature and precipitation data obtained from 160 Chinese stations.It is found that despite the lagre biases,the model was able to produce seasonal anomalies that have properties that are reasonably close to those that are observed.This anomaly is the quantity of interest when forecasting seasonal climatic conditions.The root mean squared difference(RMSD) between the forecast and observed anomaly leads us to be modestly optimistic about the prospects for using dynamical models to forecast the interannual variability of some meteorological elements. The correlation analysis of the forecast and observation also supports the result given by the RMSD analysis and provides a tool for identify the forecast confidence level in various regions,