Based on 150-year simulations of a regional climate model, RegCM3, under the Special Report on Emissions Scenarios (SRES) A1B scenario, the effective drought index (EDI) is used to project the future drought change in...Based on 150-year simulations of a regional climate model, RegCM3, under the Special Report on Emissions Scenarios (SRES) A1B scenario, the effective drought index (EDI) is used to project the future drought change in China. During the baseline period 1986-2005, RegCM3 was found to reliably simulate the spatial pattern of drought over the country. Over the 21st century, the regionally averaged EDI should increase, corresponding to a decrease of drought, while the probability of extreme drought events should increase. Geographically, drought should clearly increase in Northeast China, the middle and lower reaches of the Yangtze River valley, Southwest China, and southern Tibet but decrease in most parts of the rest of the country.展开更多
Exploring the scale-effect of different land use types on the distribution pattern of urban park green space(PGS)at multiple grid scales would inform rational allocation and efficient collaborative construction of urb...Exploring the scale-effect of different land use types on the distribution pattern of urban park green space(PGS)at multiple grid scales would inform rational allocation and efficient collaborative construction of urban development land at different scales.Selecting 300-m,500-m,1,000-m,and 2,000-m grid scales,the research employed Create Fishnet tool in ArcGIS and Geodetector to construct a scale-effect analysis framework that revealed the scale-effects of different land use types on the distribution pattern of PGS at multiple grid scales in the main urban area of Nanjing,China in 2006,2012,and 2017.Main research results are:1)the overall distribution pattern of PGS showed the evolution characteristics from polarization to advancing quality and efficiency,while the trend gradually weakened with the increase of grid scale;2)the scale-effect of other land use types on PGS increasingly enhanced-the larger the grid scale,the more obvious the synergistic or compressive effect;3)the interactive scaleeffects of different land use types gradually enhanced-the larger the grid scale,the more significant the overall factor interaction;and 4)at the 300-m grid scale,the major interaction factors were residential,transportation,industrial/manufacturing,water area,and administration/public services,which gradually changed to residential,water area,and administration/public services up to the 2,000-m grid scale.The findings of this paper are expected to deepen the theory of the coupling between PGS and other land use types,as well as provide scientific support and a basis for efficient allocation,spatial layout optimization,and sustainable development of urban spaces.展开更多
The spatial distribution of clouds and their seasonal variations, and the three-dimensional(3D) cloud structures over East Asia have been analyzed with the CALIPSO-GOCCP data during the period from 2007 to 2012. The r...The spatial distribution of clouds and their seasonal variations, and the three-dimensional(3D) cloud structures over East Asia have been analyzed with the CALIPSO-GOCCP data during the period from 2007 to 2012. The results show that there is a large cloud fraction greater than 0.7 over southern China, and the largest cloud fraction appears in southwest China. Besides, a large cloud fraction occurs over the southeast of the Tibetan Plateau. The total and high cloud fractions show notable variations with seasons, while the middle and low cloud fractions vary a little. As for cloud vertical structure, significant differences of the cloud vertical distributions are observed between over land and ocean. Cloud fractions and the height of the maximum cloud fractions decline gradually with the increasing latitude, except for the vertical-latitude profiles over the Tibetan Plateau regions. The longitude-vertical cross sections show similar patterns from the longitude 70° E to 140° E, except the profiles with large cloud fractions over the Tibetan Plateau. From the horizontal distribution patterns and vertical structures of the clouds over East Asia, it is concluded that the huge terrain of the Tibetan Plateau has significant impacts on the cloud formation over the Tibetan Plateau region and the areas to the east. At last, the clouds from the CALIPSO-GOCCP observations are compared to those from the ERA-Interim reanalysis data. The results indicate that the ERA-Interim reanalysis data provide reasonable spatial distribution patterns and the vertical structures in terms of the total cloud fraction over East Asia. However, the total cloud fraction was underestimated about 20% by the ERA-Interim reanalysis data over most parts of East Asia, especially over the neighboring areas east of the Tibetan Plateau. Additionally, the ERA-interim reanalysis data overestimate the cloud fractions at each level in the vertical direction.展开更多
基金supported by the National Basic Research Program of China(Grant No.2009CB421407)the National Natural Science Foundation of China(Grant No.41130103)
文摘Based on 150-year simulations of a regional climate model, RegCM3, under the Special Report on Emissions Scenarios (SRES) A1B scenario, the effective drought index (EDI) is used to project the future drought change in China. During the baseline period 1986-2005, RegCM3 was found to reliably simulate the spatial pattern of drought over the country. Over the 21st century, the regionally averaged EDI should increase, corresponding to a decrease of drought, while the probability of extreme drought events should increase. Geographically, drought should clearly increase in Northeast China, the middle and lower reaches of the Yangtze River valley, Southwest China, and southern Tibet but decrease in most parts of the rest of the country.
文摘Exploring the scale-effect of different land use types on the distribution pattern of urban park green space(PGS)at multiple grid scales would inform rational allocation and efficient collaborative construction of urban development land at different scales.Selecting 300-m,500-m,1,000-m,and 2,000-m grid scales,the research employed Create Fishnet tool in ArcGIS and Geodetector to construct a scale-effect analysis framework that revealed the scale-effects of different land use types on the distribution pattern of PGS at multiple grid scales in the main urban area of Nanjing,China in 2006,2012,and 2017.Main research results are:1)the overall distribution pattern of PGS showed the evolution characteristics from polarization to advancing quality and efficiency,while the trend gradually weakened with the increase of grid scale;2)the scale-effect of other land use types on PGS increasingly enhanced-the larger the grid scale,the more obvious the synergistic or compressive effect;3)the interactive scaleeffects of different land use types gradually enhanced-the larger the grid scale,the more significant the overall factor interaction;and 4)at the 300-m grid scale,the major interaction factors were residential,transportation,industrial/manufacturing,water area,and administration/public services,which gradually changed to residential,water area,and administration/public services up to the 2,000-m grid scale.The findings of this paper are expected to deepen the theory of the coupling between PGS and other land use types,as well as provide scientific support and a basis for efficient allocation,spatial layout optimization,and sustainable development of urban spaces.
基金supported by the National Natural Science Foundation of China(Grant No.41405006)the China Special Fund for Meteorological Research in the Public Interest(Grant Nos.GYHY201406003+3 种基金GYHY-201406001)the National Basic Research Program of China(Grant No.2012CB417204)the Basic Research Fund of the Chinese Academy of Meteorological Sciences(Grant Nos.2014R0162015Z003)
文摘The spatial distribution of clouds and their seasonal variations, and the three-dimensional(3D) cloud structures over East Asia have been analyzed with the CALIPSO-GOCCP data during the period from 2007 to 2012. The results show that there is a large cloud fraction greater than 0.7 over southern China, and the largest cloud fraction appears in southwest China. Besides, a large cloud fraction occurs over the southeast of the Tibetan Plateau. The total and high cloud fractions show notable variations with seasons, while the middle and low cloud fractions vary a little. As for cloud vertical structure, significant differences of the cloud vertical distributions are observed between over land and ocean. Cloud fractions and the height of the maximum cloud fractions decline gradually with the increasing latitude, except for the vertical-latitude profiles over the Tibetan Plateau regions. The longitude-vertical cross sections show similar patterns from the longitude 70° E to 140° E, except the profiles with large cloud fractions over the Tibetan Plateau. From the horizontal distribution patterns and vertical structures of the clouds over East Asia, it is concluded that the huge terrain of the Tibetan Plateau has significant impacts on the cloud formation over the Tibetan Plateau region and the areas to the east. At last, the clouds from the CALIPSO-GOCCP observations are compared to those from the ERA-Interim reanalysis data. The results indicate that the ERA-Interim reanalysis data provide reasonable spatial distribution patterns and the vertical structures in terms of the total cloud fraction over East Asia. However, the total cloud fraction was underestimated about 20% by the ERA-Interim reanalysis data over most parts of East Asia, especially over the neighboring areas east of the Tibetan Plateau. Additionally, the ERA-interim reanalysis data overestimate the cloud fractions at each level in the vertical direction.
