Based on current research, the characteristics and action mechanism of biological nitrification inhibitors at home and abroad were reviewed by combining with the latest research progress. The application effects of bi...Based on current research, the characteristics and action mechanism of biological nitrification inhibitors at home and abroad were reviewed by combining with the latest research progress. The application effects of biological nitrification inhibitors on agricultural production were summarized. Research hotspot and achievements of biological nitrification inhibitors at home and abroad were summarized. The research direction in future was forecasted.展开更多
目的探究分析温阳利湿化瘀方对先天性心脏病(简称先心病)患儿术后转归及营养状态的影响。方法以2020年1月—2021年9月于医院确诊并收治入院的148例先天性心脏病患儿作为研究对象,全部患儿按照随机数字表法随机分为观察组(74例)和对照组...目的探究分析温阳利湿化瘀方对先天性心脏病(简称先心病)患儿术后转归及营养状态的影响。方法以2020年1月—2021年9月于医院确诊并收治入院的148例先天性心脏病患儿作为研究对象,全部患儿按照随机数字表法随机分为观察组(74例)和对照组(74例),对照组患儿在术后严格限制能量及水的摄入,给予普通奶粉进行喂养,观察组患儿在对照组基础上给予传统中医温阳利湿化瘀方治疗,均治疗至患儿出院。对比两组患儿术后机械通气时间、儿科重症监护室(pediatric intensive care unit,PICU)治疗时间、住院时间、不良反应发生情况、营养情况对比及心功能。结果观察组患儿术后机械通气时间、PICU治疗时间、住院时间均显著少于对照组,不良反应发生率显著低于对照组,差异均有统计学意义(P<0.05)。两组患儿术前血清前清蛋白(prealbumin,PA)、清蛋白(albumin,ALB)、总蛋白(total protein,TP)等营养指标,差异无统计学意义(P>0.05)。术后两组患儿PA、ALB、TP均高于术前,观察组PA、ALB、TP明显高于对照组,差异均有统计学意义(P<0.05)。经不同方式治疗后,观察组患儿术后心功能情况显著优于对照组,差异均有统计学意义(P<0.05)。结论温阳利湿化瘀方可以明显提高先心病患儿术后营养状态,改善术后心功能,治疗效果显著,值得临床推广应用。展开更多
[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightn...[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightness temperature in the Yangtze River Delta area was calculated,and its rules and reasons were also discussed in this study.[Result] Different land use types had its own special brightness temperature variation.During the day,the brightness temperature was as follows：grassland or urban and built-up landcropland,forest land and barrenwetland and water.During the night,the brightness temperature was as follows：water,wetland and barrengrassland or urban and built-up landforest land and cropland.Brightness temperature showed the trend of high in summer and low in winter or increasing in spring and decreasing in fall.The characteristics of surface thermal radiation could be reflected better by brightness temperature at night.Solar radiation,mixed pixel,heat capacity,water content were the main reasons for the difference of brightness temperature in different land types.[Conclusion] The brightness temperature variation of different land use types has significance for water content analysis in soil and dynamic monitoring of land use.展开更多
Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, ...Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.展开更多
As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep co...As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep coal resources. Therefore, reducing the working face temperature to improve working conditions by controlling these heat hazards is an urgent problem. Considering problems in cooling deep mines both domestically and abroad along with the actual conditions of the Zhangshuanglou coal mine, we propose a HEMS technology that uses heat resources from deep mines in a stepwise manner. HEMS means a high temperature ex-change machinery system. Mine inrush-water is used as a source of cooling. Twice the energy is extracted from the mine inrush water. Heat is used for building heating in the winter and cold water is used for cooling buildings in the summer. This opens a new technology for stepwise utilization of heat energy in deep mines. Energy conservation and reduced pollution, an improved environment and sustainable economic development are realized by this technique. The economic and social effects are obvious and illustrate a good prospect for the application and extension of the method.展开更多
Transformation of mineral matter is important for coal utilization at high temperatures.This is especially true for blended coal.XRD and FTIR were employed together to study the transformation of mineral matter at hig...Transformation of mineral matter is important for coal utilization at high temperatures.This is especially true for blended coal.XRD and FTIR were employed together to study the transformation of mineral matter at high temperature in blended coals.It was found that the concentration of catalytic minerals, namely iron oxides, increases with an increasing ratio of Shenfu coal, which could improve coal gasification.The transformation characteristics of the minerals in blended coals are not exactly predictable from the blend ratio.This was proved by comparing the iron oxide content to the blending ratio.The results from FTIR are comparable with those from XRD.FTIR is an effective method for examining variation in mineral matter.展开更多
The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean...The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean variability on ENSO have increased during this period.To improve ENSO predictability,the authors investigate the influence of the extratropical Atlantic and Pacific oceans on ENSO during the pre-2000 and post-2000 periods,and find that the influence of the northern tropical Atlantic sea surface temperature(NTA SST)on ENSO has significantly increased since 2000.Furthermore,there is a much earlier and stronger correlation between NTA SST and ENSO over the central-eastern Pacific during June-July-August in the post-2000 period compared with the pre-2000 period.The extratropical Pacific SST predictors for ENSO retain an approximate 10-month lead time after 2000.The authors use SST signals in the extratropical Atlantic and Pacific to predict ENSO using a statistical prediction model.This results in a significant improvement in ENSO prediction skill and an obvious decrease in the spring predictability barrier phenomenon of ENSO.These results indicate that extratropical Atlantic and Pacific SSTs can make substantial contributions to ENSO prediction,and can be used to enhance ENSO predictability after 2000.展开更多
Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,w...Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,where air temperature data have good quality.Some missing data were recovered using the method of differences. A significant mean annual air temperature rise happened in high mountainous parts of Bulgaria- the warming is in the order of 0.7°C for the entire period.The increase is very prominent particularly in the last 30 years.Main contributors to this overall tendency are summer months-June,July and August.To some degree,January also could be included in this group.November trend shows temperature rise at the beginning of the investigated period.One of the causes for such a tendency is atmosphere circulation in respective months.It also shows signs of considerable reorganization in both winter and summer.There is an increase of the cases of warm atmosphere patterns typical for winter, summer and autumn seasons in Bulgaria.Meridional circulation has essential significance for air temperatures during the cold half of the year.In January and June atmosphere circulation has a substantial influence on the thermal regime of air in high mountains of Bulgaria.In July,August and November this influence is reduced.There are no cycles in air temperatures for the investigated period.展开更多
A regional climate model （RegCM4） is em- ployed to investigate the impacts of land use/cover change （LUCC） on the climate over the eastern part of Northwest China （ENW） in the periods of 2001 and 2011. The re- s...A regional climate model （RegCM4） is em- ployed to investigate the impacts of land use/cover change （LUCC） on the climate over the eastern part of Northwest China （ENW） in the periods of 2001 and 2011. The re- sults indicated that the LUCC in ENW, which was char-acterized by desert retreat, reforestation, and farmland expansion, led to significant local changes in surface air temperature （within -0.3℃） and slight regional changes in precipitation （within -15%） in summer. In the desert retreat area, the net absorbed shortwave radiation had a greater influence than evaporative cooling, leading to increases in the daily mean and maximum temperature. Besides, the daily mean and maximum temperatures in- creased in the reforestation area but decreased in the farmland expansion area. As surface albedo showed no significant change in these regions, the temperature in- crease in the reforestation area can be attributed to a decrease in evaporation, while the opposite effect appears to have been the case in the farmland expansion area.展开更多
The effect of climate change in recent times has disrupted the onset and duration of seasons in Nigeria manifesting in the reduction of both staple and cash crops, and livestock yields. This has transformed the countr...The effect of climate change in recent times has disrupted the onset and duration of seasons in Nigeria manifesting in the reduction of both staple and cash crops, and livestock yields. This has transformed the country to a major importer of those agricultural produce she hitherto exported. As a country where over 70% of the population depends on agriculture for survival, the impacts of climate change are a major threat to both food security and the general econoray. Remedial measures which have been suggested including adoption of agronomic and tested practices, reduced burning and afforestation. An option that could be of great potential in ameliorating this situation but which has not been practiced especially in the production of specialty crops is the use of greenhouse farming. This paper discusses the impact of climate change on Nigerian agriculture. The potentials and logistics are required for effective use of greenhouse farming as an adaptation to climate change in Nigeria. It is suggested that research should be carded out to select appropriate glazing materials. The provisions of training and credit facilities for interested farmers are recommended for effective utilization of the system.展开更多
Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover（LULC） changes caused by the rapid economic development and human activities that have occurred over the past few de...Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover（LULC） changes caused by the rapid economic development and human activities that have occurred over the past few decades in East Asia and China. The effects of LULC changes on the radiation budget and 2-m surface air temperature（SAT） were explored for the period using the Weather Research and Forecasting（WRF） model. The mosaic approach, which considers the N-most abundant land use types within a model grid cell（here, N = 3） and precisely describes the subgridscale LULC changes, was adopted in the integrations. The impacts of LULC changes based on two 36-year integrations showed that SAT generally decreased, with the sole exception being over eastern China, resulting in decreased SAT in China（-0.062 °C） and East Asian land areas（EAL,-0.061 °C）. The LULC changes induced changes in albedo, which influenced the radiation budget. The radiative forcings at the top of the atmosphere were-0.56 W m-2 across the whole of China, and-0.50 W m-2 over EAL. Meanwhile, the altered roughness length mainly influenced near-surface wind speeds, large-scale and upward moisture fluxes, latent heat fluxes, and cloud fractions at different altitudes. Though the impacts caused by the LULC changes were generally smaller at regional scales, the values at local scales were much stronger.展开更多
This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR ...This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR events with zonal extent exceeding 90°of longitude on the peak day are identified.Using self-organizing map(SOM),the LSTRs are classified into five clusters that are characterized by different spatial distributions and orientations.The leading two clusters are closely associated with extensive and persistent cold events over different places.Considering the first cluster,LSTRs extend from the Ural Mountains to Northeast Asia and are favorable for the amplification and southeastward extension of the Siberian high.Therefore,this cluster is closely associated with the occurrence of extensive and persistent cold events in china.In comparison with the first cluster,the LSTRs of second group are situated to the west,with starting points from the Kola Peninsula,and cause extensive and persistent cold events over Eastern Europe,central Asia,and central Siberia.The results suggest that the vertical coupling between LSTRs and the corresponding anomalous sea level pressure is crucial for the persistent cold temperature events associated with the leading two SOM clusters.展开更多
The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly...The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.展开更多
基金Supported by Tibet Natural Science Foundation(ZJ2014068)School-level Key Project of Tibet Vocational Technical College(2012L07)~~
文摘Based on current research, the characteristics and action mechanism of biological nitrification inhibitors at home and abroad were reviewed by combining with the latest research progress. The application effects of biological nitrification inhibitors on agricultural production were summarized. Research hotspot and achievements of biological nitrification inhibitors at home and abroad were summarized. The research direction in future was forecasted.
文摘目的探究分析温阳利湿化瘀方对先天性心脏病(简称先心病)患儿术后转归及营养状态的影响。方法以2020年1月—2021年9月于医院确诊并收治入院的148例先天性心脏病患儿作为研究对象,全部患儿按照随机数字表法随机分为观察组(74例)和对照组(74例),对照组患儿在术后严格限制能量及水的摄入,给予普通奶粉进行喂养,观察组患儿在对照组基础上给予传统中医温阳利湿化瘀方治疗,均治疗至患儿出院。对比两组患儿术后机械通气时间、儿科重症监护室(pediatric intensive care unit,PICU)治疗时间、住院时间、不良反应发生情况、营养情况对比及心功能。结果观察组患儿术后机械通气时间、PICU治疗时间、住院时间均显著少于对照组,不良反应发生率显著低于对照组,差异均有统计学意义(P<0.05)。两组患儿术前血清前清蛋白(prealbumin,PA)、清蛋白(albumin,ALB)、总蛋白(total protein,TP)等营养指标,差异无统计学意义(P>0.05)。术后两组患儿PA、ALB、TP均高于术前,观察组PA、ALB、TP明显高于对照组,差异均有统计学意义(P<0.05)。经不同方式治疗后,观察组患儿术后心功能情况显著优于对照组,差异均有统计学意义(P<0.05)。结论温阳利湿化瘀方可以明显提高先心病患儿术后营养状态,改善术后心功能,治疗效果显著,值得临床推广应用。
基金Supported by National Scientific and Technological Support Project(2008BAC34B07)Fundamental Project on Natural Science from Jiangsu provincial College (08KJA170001)~~
文摘[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightness temperature in the Yangtze River Delta area was calculated,and its rules and reasons were also discussed in this study.[Result] Different land use types had its own special brightness temperature variation.During the day,the brightness temperature was as follows：grassland or urban and built-up landcropland,forest land and barrenwetland and water.During the night,the brightness temperature was as follows：water,wetland and barrengrassland or urban and built-up landforest land and cropland.Brightness temperature showed the trend of high in summer and low in winter or increasing in spring and decreasing in fall.The characteristics of surface thermal radiation could be reflected better by brightness temperature at night.Solar radiation,mixed pixel,heat capacity,water content were the main reasons for the difference of brightness temperature in different land types.[Conclusion] The brightness temperature variation of different land use types has significance for water content analysis in soil and dynamic monitoring of land use.
文摘Nine cowsheds were used, the differences between each cowshed are orientation （east-west or north-south）, cooling （with or without）, and height （3 m, 5 m or 8 m height）. Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index （THI） and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds（differences were found to be significant）. Thereby, increasing shed height enhances dairy cows＇ microclimate under Egyptian conditions （hot climate）; consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.
基金Financial support for this project, provided by the National Basic Research Program of China (No. 2006CB202200)the National Major Project of Ministry of Education (No.304005) the Program for Changjiang Scholars and Innovative Research Team in University of China (No.IRT0656), is gratefully acknowledged
文摘As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep coal resources. Therefore, reducing the working face temperature to improve working conditions by controlling these heat hazards is an urgent problem. Considering problems in cooling deep mines both domestically and abroad along with the actual conditions of the Zhangshuanglou coal mine, we propose a HEMS technology that uses heat resources from deep mines in a stepwise manner. HEMS means a high temperature ex-change machinery system. Mine inrush-water is used as a source of cooling. Twice the energy is extracted from the mine inrush water. Heat is used for building heating in the winter and cold water is used for cooling buildings in the summer. This opens a new technology for stepwise utilization of heat energy in deep mines. Energy conservation and reduced pollution, an improved environment and sustainable economic development are realized by this technique. The economic and social effects are obvious and illustrate a good prospect for the application and extension of the method.
基金Projects 2005CB217701-03 supported by the National Basic Research Program of China2005DFA60220 by the Ministry of Science and Technology of China
文摘Transformation of mineral matter is important for coal utilization at high temperatures.This is especially true for blended coal.XRD and FTIR were employed together to study the transformation of mineral matter at high temperature in blended coals.It was found that the concentration of catalytic minerals, namely iron oxides, increases with an increasing ratio of Shenfu coal, which could improve coal gasification.The transformation characteristics of the minerals in blended coals are not exactly predictable from the blend ratio.This was proved by comparing the iron oxide content to the blending ratio.The results from FTIR are comparable with those from XRD.FTIR is an effective method for examining variation in mineral matter.
基金This research was supported by the National Natural Science Foundation of China[grant number 41975070]the Identification and mechanism study of global warming‘hiatus’phenomenon of 973 project of China[grant number 2016YFA0601801].
文摘The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean variability on ENSO have increased during this period.To improve ENSO predictability,the authors investigate the influence of the extratropical Atlantic and Pacific oceans on ENSO during the pre-2000 and post-2000 periods,and find that the influence of the northern tropical Atlantic sea surface temperature(NTA SST)on ENSO has significantly increased since 2000.Furthermore,there is a much earlier and stronger correlation between NTA SST and ENSO over the central-eastern Pacific during June-July-August in the post-2000 period compared with the pre-2000 period.The extratropical Pacific SST predictors for ENSO retain an approximate 10-month lead time after 2000.The authors use SST signals in the extratropical Atlantic and Pacific to predict ENSO using a statistical prediction model.This results in a significant improvement in ENSO prediction skill and an obvious decrease in the spring predictability barrier phenomenon of ENSO.These results indicate that extratropical Atlantic and Pacific SSTs can make substantial contributions to ENSO prediction,and can be used to enhance ENSO predictability after 2000.
文摘Changes of air temperatures and atmosphere circulation at three high mountainous stations in Bulgaria are investigated for the period of 1941-2008.The three stations are located on peaks Musala,Cherni vrah and Botev,where air temperature data have good quality.Some missing data were recovered using the method of differences. A significant mean annual air temperature rise happened in high mountainous parts of Bulgaria- the warming is in the order of 0.7°C for the entire period.The increase is very prominent particularly in the last 30 years.Main contributors to this overall tendency are summer months-June,July and August.To some degree,January also could be included in this group.November trend shows temperature rise at the beginning of the investigated period.One of the causes for such a tendency is atmosphere circulation in respective months.It also shows signs of considerable reorganization in both winter and summer.There is an increase of the cases of warm atmosphere patterns typical for winter, summer and autumn seasons in Bulgaria.Meridional circulation has essential significance for air temperatures during the cold half of the year.In January and June atmosphere circulation has a substantial influence on the thermal regime of air in high mountains of Bulgaria.In July,August and November this influence is reduced.There are no cycles in air temperatures for the investigated period.
基金supported by the Laboratory for Climate Studies Open Funds for Young Scholars (2014)the National Natural Science Foundation of China (Grant Nos. 41405101 and 41375104)the R&D Special Fund for Public Welfare Industry (Meteorology) (Grant No. GYHY201306019)
文摘A regional climate model （RegCM4） is em- ployed to investigate the impacts of land use/cover change （LUCC） on the climate over the eastern part of Northwest China （ENW） in the periods of 2001 and 2011. The re- sults indicated that the LUCC in ENW, which was char-acterized by desert retreat, reforestation, and farmland expansion, led to significant local changes in surface air temperature （within -0.3℃） and slight regional changes in precipitation （within -15%） in summer. In the desert retreat area, the net absorbed shortwave radiation had a greater influence than evaporative cooling, leading to increases in the daily mean and maximum temperature. Besides, the daily mean and maximum temperatures in- creased in the reforestation area but decreased in the farmland expansion area. As surface albedo showed no significant change in these regions, the temperature in- crease in the reforestation area can be attributed to a decrease in evaporation, while the opposite effect appears to have been the case in the farmland expansion area.
文摘The effect of climate change in recent times has disrupted the onset and duration of seasons in Nigeria manifesting in the reduction of both staple and cash crops, and livestock yields. This has transformed the country to a major importer of those agricultural produce she hitherto exported. As a country where over 70% of the population depends on agriculture for survival, the impacts of climate change are a major threat to both food security and the general econoray. Remedial measures which have been suggested including adoption of agronomic and tested practices, reduced burning and afforestation. An option that could be of great potential in ameliorating this situation but which has not been practiced especially in the production of specialty crops is the use of greenhouse farming. This paper discusses the impact of climate change on Nigerian agriculture. The potentials and logistics are required for effective use of greenhouse farming as an adaptation to climate change in Nigeria. It is suggested that research should be carded out to select appropriate glazing materials. The provisions of training and credit facilities for interested farmers are recommended for effective utilization of the system.
基金supported by the National Natural Science Foun-dation of China[grant numbers 41775087 and 41675149]the National Key R&D Program of China[grant number 2016YFA0600403]+2 种基金the Chinese Academy of Sciences Strategic Priority Program[grant number XDA05090206]the National Key Basic Research Program on Global Change[grant number 2011CB952003]the Jiangsu Collaborative Innovation Center for Climatic Change
文摘Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover（LULC） changes caused by the rapid economic development and human activities that have occurred over the past few decades in East Asia and China. The effects of LULC changes on the radiation budget and 2-m surface air temperature（SAT） were explored for the period using the Weather Research and Forecasting（WRF） model. The mosaic approach, which considers the N-most abundant land use types within a model grid cell（here, N = 3） and precisely describes the subgridscale LULC changes, was adopted in the integrations. The impacts of LULC changes based on two 36-year integrations showed that SAT generally decreased, with the sole exception being over eastern China, resulting in decreased SAT in China（-0.062 °C） and East Asian land areas（EAL,-0.061 °C）. The LULC changes induced changes in albedo, which influenced the radiation budget. The radiative forcings at the top of the atmosphere were-0.56 W m-2 across the whole of China, and-0.50 W m-2 over EAL. Meanwhile, the altered roughness length mainly influenced near-surface wind speeds, large-scale and upward moisture fluxes, latent heat fluxes, and cloud fractions at different altitudes. Though the impacts caused by the LULC changes were generally smaller at regional scales, the values at local scales were much stronger.
基金jointly supported by the National Natural Science Foundation of China [grant number 41375064 and41675086]the National Key Technology Research and Development Program of the Ministry of Science and Technology of China [grant number 2015BAC03B03]
文摘This study investigates the major patterns of large-scale tilted ridges(LSTRS)over the Eurasian continent and their connections with large-scale surface air temperature during boreal winter.A total number of 134 LSTR events with zonal extent exceeding 90°of longitude on the peak day are identified.Using self-organizing map(SOM),the LSTRs are classified into five clusters that are characterized by different spatial distributions and orientations.The leading two clusters are closely associated with extensive and persistent cold events over different places.Considering the first cluster,LSTRs extend from the Ural Mountains to Northeast Asia and are favorable for the amplification and southeastward extension of the Siberian high.Therefore,this cluster is closely associated with the occurrence of extensive and persistent cold events in china.In comparison with the first cluster,the LSTRs of second group are situated to the west,with starting points from the Kola Peninsula,and cause extensive and persistent cold events over Eastern Europe,central Asia,and central Siberia.The results suggest that the vertical coupling between LSTRs and the corresponding anomalous sea level pressure is crucial for the persistent cold temperature events associated with the leading two SOM clusters.
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)[grant number XDA19030403]the National Natural Science Foundation of China [grant number 41575095]+2 种基金the CAS ‘Belt and Road Initiatives’ Program on International Cooperation [grant number 134111KYSB20160010]Victor Nnamdi DIKE acknowledges support from the CAS–TWAS(The World Academy of Sciences)President FellowshipHyacinth NNAMCHI is supported by the International Federation for Science(W/4849)
文摘The long-term trend of diurnal temperature range(DTR)over Nigeria was examined using daily station-based datasets for the period 1971–2013.The results show that the regionally averaged DTR has decreased significantly(-0.34°C per decade)over the Nigerian Sahel(north of 10°N),but there has been a slight increasing trend(0.01°C per decade)over the Nigerian Guinea Coast.The annual decreasing trend of DTR in the Nigerian Sahel is mainly attributable to the significant increasing trend in daily minimum temperature(Tmin,0.51°C per decade),which far outstrips the rate of increase in the daily maximum(Tmax,0.17°C per decade).In contrast,the comparable trends in Tmin(0.19°C per decade)and Tmax(0.20°C per decade)may explain the non-significant trend of the DTR averaged over the Guinea Coast region.It is observed that the DTR has decreased more in boreal summer(June–July–August)than in boreal winter(December–January–February)for the regions.Furthermore,it is found that the significant DTR declining trend over the Nigerian Sahel is closely associated with an increasing trend of annual and summer precipitation in the region,but the increasing DTR trend in the Nigerian Guinea Coast region can be attributed to the decreasing trend of cloud cover over the region.
