Landsat Thematic Mapper （TM） and Enhanced Thematic Mapper Plus （ETM＋） images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes （LUCC） in the Zhejiang coastal region wi...Landsat Thematic Mapper （TM） and Enhanced Thematic Mapper Plus （ETM＋） images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes （LUCC） in the Zhejiang coastal region with a stratified unsupervised classification technique in conjunction with visual interpretation and to attempt an identification of the socioeconomic driving forces. In level I an overall accurate classification was achieved using a modified Anderson＇s Ⅰ/Ⅱ/Ⅲ-level classification scheme. The overall accuracy of the land use classification at Anderson level Ⅰ were 89.7% （1985）, 91.6% （1993）, and 90.4% （2001）. The most rapid land use change was a dramatic increase in urban or built-up areas, which quadrupled from 1985 to 2001. Over 90% of this newly expanded built-up area was originally paddy fields or other croplands. In different parts of the Zhejiang coastal region, urban land expansion was spatially uneven. Temporally, land use development did not stabilized, and the two study periods of time （1985-1993 and 1993-2001） had different transition styles. Socioeconomic factors, such as gross domestic product, total population, and financial expenditure, were all highly correlated with the expansion of urban or built-up areas. Based on the degree of urban sprawl and socioeconomic factors, cities and towns were further divided into six subgroups, which may help decision makers improve land use for the region.展开更多
基于耦合了CAMS(Chinese Academy of Meteorological Sciences)云微物理方案的WRF(Weather Research and Forecasting Model)中尺度模式,针对2024年3月24日丹江口流域一次受中纬度西风槽东移与低层暖湿输送控制的积层混合云降水过程,系...基于耦合了CAMS(Chinese Academy of Meteorological Sciences)云微物理方案的WRF(Weather Research and Forecasting Model)中尺度模式,针对2024年3月24日丹江口流域一次受中纬度西风槽东移与低层暖湿输送控制的积层混合云降水过程,系统模拟了人工冰晶播撒对云微物理过程及降水的影响。结果表明,此次降水过程呈现暖云与冷云降水机制共存的特征:降水初期至旺盛期以暖云碰并主导,19:00(北京时间)后以霰粒子融化过程主导。目标云系云顶高度超过12 km,4~6 km层过冷水含量约0.01~0.3 g/kg,自然冰晶浓度较低,结合上升气流成为理想催化区。在冷暖云降水机制协同作用下播撒人工冰晶(SC1)发现,催化后影响区地面降水呈现先减少后增加的变化。催化后30分钟内,冰晶凝华增长后碰并雪晶,雪晶增加,但增多的雪晶没有下落到暖区融化成雨滴,反而云滴和霰的减少导致了雨滴碰并云滴和霰融化成雨滴减少,最终地面降水减少。催化后50分钟至3 h,下游区域霰收集雪晶和霰融化过程增强,为暖区上层提供初始大雨滴,导致雨滴碰并云滴过程也增强,最终冷暖云降水过程都增强导致地面降水增加,整个评估区内3 h累积增雨量为2.438×10^(5)t。敏感性试验表明,过量播撒冰晶会因水汽消耗削弱霰的源项,导致霰融化减弱,增雨量减少;单一高度层的敏感性试验表明,云中5.2 km即-7℃温度层催化增雨效果最优。因此,协同优化积层混合云催化的播撒剂量与高度等,可显著提升降水效率,为丹江口流域云水资源调控提供科学依据。展开更多
文摘Landsat Thematic Mapper （TM） and Enhanced Thematic Mapper Plus （ETM＋） images in 1985, 1986, 1993, 1994 and 2001 were used to quantify the land use and land cover changes （LUCC） in the Zhejiang coastal region with a stratified unsupervised classification technique in conjunction with visual interpretation and to attempt an identification of the socioeconomic driving forces. In level I an overall accurate classification was achieved using a modified Anderson＇s Ⅰ/Ⅱ/Ⅲ-level classification scheme. The overall accuracy of the land use classification at Anderson level Ⅰ were 89.7% （1985）, 91.6% （1993）, and 90.4% （2001）. The most rapid land use change was a dramatic increase in urban or built-up areas, which quadrupled from 1985 to 2001. Over 90% of this newly expanded built-up area was originally paddy fields or other croplands. In different parts of the Zhejiang coastal region, urban land expansion was spatially uneven. Temporally, land use development did not stabilized, and the two study periods of time （1985-1993 and 1993-2001） had different transition styles. Socioeconomic factors, such as gross domestic product, total population, and financial expenditure, were all highly correlated with the expansion of urban or built-up areas. Based on the degree of urban sprawl and socioeconomic factors, cities and towns were further divided into six subgroups, which may help decision makers improve land use for the region.
文摘基于耦合了CAMS(Chinese Academy of Meteorological Sciences)云微物理方案的WRF(Weather Research and Forecasting Model)中尺度模式,针对2024年3月24日丹江口流域一次受中纬度西风槽东移与低层暖湿输送控制的积层混合云降水过程,系统模拟了人工冰晶播撒对云微物理过程及降水的影响。结果表明,此次降水过程呈现暖云与冷云降水机制共存的特征:降水初期至旺盛期以暖云碰并主导,19:00(北京时间)后以霰粒子融化过程主导。目标云系云顶高度超过12 km,4~6 km层过冷水含量约0.01~0.3 g/kg,自然冰晶浓度较低,结合上升气流成为理想催化区。在冷暖云降水机制协同作用下播撒人工冰晶(SC1)发现,催化后影响区地面降水呈现先减少后增加的变化。催化后30分钟内,冰晶凝华增长后碰并雪晶,雪晶增加,但增多的雪晶没有下落到暖区融化成雨滴,反而云滴和霰的减少导致了雨滴碰并云滴和霰融化成雨滴减少,最终地面降水减少。催化后50分钟至3 h,下游区域霰收集雪晶和霰融化过程增强,为暖区上层提供初始大雨滴,导致雨滴碰并云滴过程也增强,最终冷暖云降水过程都增强导致地面降水增加,整个评估区内3 h累积增雨量为2.438×10^(5)t。敏感性试验表明,过量播撒冰晶会因水汽消耗削弱霰的源项,导致霰融化减弱,增雨量减少;单一高度层的敏感性试验表明,云中5.2 km即-7℃温度层催化增雨效果最优。因此,协同优化积层混合云催化的播撒剂量与高度等,可显著提升降水效率,为丹江口流域云水资源调控提供科学依据。
