To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeaste...To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.展开更多
According to the textual research into the historical documents dominated by archives yearly, as well as the verification with several other kinds of data, the later or earlier starting time of the rainy seasons in Yu...According to the textual research into the historical documents dominated by archives yearly, as well as the verification with several other kinds of data, the later or earlier starting time of the rainy seasons in Yunnan during 1711-1982 has been reconstructed. The analysis indicates that there are obvious fluctuations in the starting date of the rainy seasons in Yunnan in a year or years, and long fluctuation on the decadal scale. The rainy season comes earlier in the early 18th century, later in the 19th century and earlier again in the 20th century. This reflects to a certain degree the gradual change of the summer monsoon in Yunnan. There exists an obvious quasi-3 years cycle, which is related to EI-Nino＇s quasi-3 years cycle, and a 11.3-year cycle which is notably related to the 11-year cycle of the solar activity of starting date of the rainy seasons in Yunnan. Meanwhile, the dissertation finds that the EI-Nino is very important to the starting date of the rainy seasons in Yunnan. The starting date of the rainy seasons in Yunnan often comes later or normally in the year of EI-Nino. However, there is an obvious imperfect period in such influence, which in turn may mean that there is a certain fluctuation in the effect of ENSO on Asian summer monsoon.展开更多
As a result of more and more serious energy risks, the study of national energy security zoning is not only the basic requirement of energy risk management but also the new demand of economic development for the energ...As a result of more and more serious energy risks, the study of national energy security zoning is not only the basic requirement of energy risk management but also the new demand of economic development for the energy industry. Firstly, this paper analyzes the basic situation of energy resources and production and consumption of primary. energy from 1996 to 2005 in China. Secondly; this paper founds an Energy Security Index System formed by six indices including the percentage of energy reserves, interlocal dependent degree, energy elasticity coefficient and so on. It subsequently calculates the weight of these indices with the factor analysis rating method Lastly, the paper evaluates and zones the abilities of energy security of 30 provinces in China with the grey chuster method According to their security; the 30 provinces are classified into three different levels： high, medium, and low levels. The regions at low energy security level include Beijing, Shanghai, Zhejiang, Fujian, Guangdong, Guangxi and Hainan. They are mainly littoral and short of primary energy production while mostly dependent on other provinces. Those at medium energy security level include 15 provinces （cities or districts）, such as Liaoning, Tianjin, Hebei, Shandong, Henan, Hunan and so on. These provinces are in the northeast, north, east of and central China. Those at high energy security level contain Shanxi. lnner Mongolia, Heilongjiang, Jilin, Chongqing, Sichuan, Shaanxi. Xinjiang. These provinces are the main primary energy production bases.展开更多
Based on plant phenology data from 26 stations of the Chinese Phenology Observation Network of the Chinese Academy of Sciences and the climate data, the change of plant phenophase in spring and the impact of climate w...Based on plant phenology data from 26 stations of the Chinese Phenology Observation Network of the Chinese Academy of Sciences and the climate data, the change of plant phenophase in spring and the impact of climate warming on the plant phenophase in China for the last 40 years are analyzed. Furthermore, the geographical distribution models of phenophase in every decade are reconstructed, and the impact of climate warming on geographical distribution model of phenophase is studied as well. The results show that (i) the response of phenophase advance or delay to temperature change is nonlinear. Since the 1980s, at the same amplitude of temperature change, phenophase delay amplitude caused by temperature decrease is greater than phenophase advance amplitude caused by temperature increase; the rate of phenophase advance days decreases with temperature increase amplitude, and the rate of phenophase delay days increases with temperature decrease amplitude. (ii) The geographical distribution model between展开更多
The reconstructed temperature anomalies in the eastern China were compared with the output from a 1000-year model simulation in an attempt to evaluate the model’s regional simulation skills and to understand the caus...The reconstructed temperature anomalies in the eastern China were compared with the output from a 1000-year model simulation in an attempt to evaluate the model’s regional simulation skills and to understand the causes of climate change in China over the last millennium. The reconstructed data are the winter half-year temperature anomalies in the central region of eastern China (25°-40°N, east of 105°E) for the last 1000 years with a 30-year resolu- tion. The model used is the global atmosphere-ocean coupled climate model, ECHO-G, which was driven by time-varying external forcings including solar radiation, volcanic erup- tions, and greenhouse gas concentrations (CO2 and CH4) for the same period. The correlation coefficient between the simulated and reconstructed time series is 0.37, which is sta- tistically significant at a confidence level of 97.5%. The Me- dieval Warm Period (MWP) during 1000-1300 A.D., the Little Ice Age (LIA) during 1300-1850 A.D. and the modern warming period after 1900 A.D. are all recognizable from both the simulated and reconstructed temperatures. The anomalies associated with the LIA and the modern warming simulated by the model are in good consistency with the re- constructed counterpart. In particular during the Maunder sun-spot minimum (1670-1710 A.D.), both the simulated and reconstructed temperature anomalies reach their min- ima without any phase difference. But in the earlier MWP, significant discrepancies exist between the simulation and the reconstruction, which might reflect the degrading quality of the reconstruction data. The range of the simulated anoma- lies (1.62 K) is comparable with that of reconstructed (2.0 K). Diagnosis of the model results indicates that, during the last millennium, variations in solar radiation and volcanic activ- ity are the main controlling factors on regional temperature change, while in the recent 100 years, the change of the con- centration of greenhouse gases plays most important role in explaining the rapid temperature rising.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41001122)China Global Change Research Program(No.2010CB950102,2010CB950903)State-Sponsored Study Abroad Programs from China Scholarship Council(No.2007U21061)
文摘To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.
基金Knowledge Innovation Program of CAS, No.KZCX3-SW-321-3Key Project of the Ministry of Education of China, No.01JAZJD770008
文摘According to the textual research into the historical documents dominated by archives yearly, as well as the verification with several other kinds of data, the later or earlier starting time of the rainy seasons in Yunnan during 1711-1982 has been reconstructed. The analysis indicates that there are obvious fluctuations in the starting date of the rainy seasons in Yunnan in a year or years, and long fluctuation on the decadal scale. The rainy season comes earlier in the early 18th century, later in the 19th century and earlier again in the 20th century. This reflects to a certain degree the gradual change of the summer monsoon in Yunnan. There exists an obvious quasi-3 years cycle, which is related to EI-Nino＇s quasi-3 years cycle, and a 11.3-year cycle which is notably related to the 11-year cycle of the solar activity of starting date of the rainy seasons in Yunnan. Meanwhile, the dissertation finds that the EI-Nino is very important to the starting date of the rainy seasons in Yunnan. The starting date of the rainy seasons in Yunnan often comes later or normally in the year of EI-Nino. However, there is an obvious imperfect period in such influence, which in turn may mean that there is a certain fluctuation in the effect of ENSO on Asian summer monsoon.
基金the National Key Technology R&D Program of China – the Key Tech-nology and Demonstration for Integrated Governance of Energy and Water Resources Security Risk (Grant No. 2006BAD20B06)
文摘As a result of more and more serious energy risks, the study of national energy security zoning is not only the basic requirement of energy risk management but also the new demand of economic development for the energy industry. Firstly, this paper analyzes the basic situation of energy resources and production and consumption of primary. energy from 1996 to 2005 in China. Secondly; this paper founds an Energy Security Index System formed by six indices including the percentage of energy reserves, interlocal dependent degree, energy elasticity coefficient and so on. It subsequently calculates the weight of these indices with the factor analysis rating method Lastly, the paper evaluates and zones the abilities of energy security of 30 provinces in China with the grey chuster method According to their security; the 30 provinces are classified into three different levels： high, medium, and low levels. The regions at low energy security level include Beijing, Shanghai, Zhejiang, Fujian, Guangdong, Guangxi and Hainan. They are mainly littoral and short of primary energy production while mostly dependent on other provinces. Those at medium energy security level include 15 provinces （cities or districts）, such as Liaoning, Tianjin, Hebei, Shandong, Henan, Hunan and so on. These provinces are in the northeast, north, east of and central China. Those at high energy security level contain Shanxi. lnner Mongolia, Heilongjiang, Jilin, Chongqing, Sichuan, Shaanxi. Xinjiang. These provinces are the main primary energy production bases.
基金This work was supported by the Chinese Academy of Sciences (Grant No. KZCX2-314), the National Natural Science Foundation of China (Grant No. 49901001), and Institute of Geographic Sciences and Natural Resources Research, the Chinese Academy of Sciences
文摘Based on plant phenology data from 26 stations of the Chinese Phenology Observation Network of the Chinese Academy of Sciences and the climate data, the change of plant phenophase in spring and the impact of climate warming on the plant phenophase in China for the last 40 years are analyzed. Furthermore, the geographical distribution models of phenophase in every decade are reconstructed, and the impact of climate warming on geographical distribution model of phenophase is studied as well. The results show that (i) the response of phenophase advance or delay to temperature change is nonlinear. Since the 1980s, at the same amplitude of temperature change, phenophase delay amplitude caused by temperature decrease is greater than phenophase advance amplitude caused by temperature increase; the rate of phenophase advance days decreases with temperature increase amplitude, and the rate of phenophase delay days increases with temperature decrease amplitude. (ii) The geographical distribution model between
基金supported by the Innovation Key Project of Chinese Academy of Sciences(Grant No.KZCX3-SW-321)the National Natural Science Foundation of China(Grant Nos.40272123,40475035,40331013)the lnnovation Project of Nanjing Institute of Geography and Limnology(Grant No.CXNIGLAS-A02-06).
文摘The reconstructed temperature anomalies in the eastern China were compared with the output from a 1000-year model simulation in an attempt to evaluate the model’s regional simulation skills and to understand the causes of climate change in China over the last millennium. The reconstructed data are the winter half-year temperature anomalies in the central region of eastern China (25°-40°N, east of 105°E) for the last 1000 years with a 30-year resolu- tion. The model used is the global atmosphere-ocean coupled climate model, ECHO-G, which was driven by time-varying external forcings including solar radiation, volcanic erup- tions, and greenhouse gas concentrations (CO2 and CH4) for the same period. The correlation coefficient between the simulated and reconstructed time series is 0.37, which is sta- tistically significant at a confidence level of 97.5%. The Me- dieval Warm Period (MWP) during 1000-1300 A.D., the Little Ice Age (LIA) during 1300-1850 A.D. and the modern warming period after 1900 A.D. are all recognizable from both the simulated and reconstructed temperatures. The anomalies associated with the LIA and the modern warming simulated by the model are in good consistency with the re- constructed counterpart. In particular during the Maunder sun-spot minimum (1670-1710 A.D.), both the simulated and reconstructed temperature anomalies reach their min- ima without any phase difference. But in the earlier MWP, significant discrepancies exist between the simulation and the reconstruction, which might reflect the degrading quality of the reconstruction data. The range of the simulated anoma- lies (1.62 K) is comparable with that of reconstructed (2.0 K). Diagnosis of the model results indicates that, during the last millennium, variations in solar radiation and volcanic activ- ity are the main controlling factors on regional temperature change, while in the recent 100 years, the change of the con- centration of greenhouse gases plays most important role in explaining the rapid temperature rising.
