透视地球工程对全球陆地气候变化趋势和波动特征的影响及区域差异

为诊断地球工程对全球陆地气候变化趋势和波动特征的影响，采用 BNU－ESM 模式的地球工程和非地球工程情景日值气温和降水数据，对比分析了两种情景下整个研究时段( 2010—2099 年) 、地球工程实施期间( 2020—2069 年) 和地球工程实施结束后( 2070—2099 年) 的全球陆地气候变化特征及区域差异。结果表明: ( 1) 两种情景下全球陆地气温变化趋势空间格局的一致性优于降雨量变化趋势空间格局。3 个时段全球陆地气温主要以增加趋势为主，2070—2099 年两种情景下开始出现减少趋势。地球工程在不同时段改变了不同区域和次区域降雨量变化趋势的方向。( 2) 地球工程在 3 个时段对全球陆地气温变化趋势的影响具有异质性。地球工程在 2010—2099 年对气温增减趋势影响最小，多介于－0. 2 ～ 0. 2 ℃ /( 10 a) 之间; 在 2020—2069 年对气温增加趋势的抑制作用最大，多数地区抑制幅度超过了 0. 4 ℃ /( 10 a) ; 在 2070—2099 年对气温增加趋势的促进作用最大，多数地区促进幅度超过了 0. 4℃ /( 10 a) 。地球工程实施前后全球陆地降雨量变化趋势差异增大，尤其是在中低纬度地区呈现出明显的区域与次区域特征。( 3) 地球工程未对全球气候的波动性产生根本改变。两种情景下的全球陆地气温和降雨量的波动特征具有较好的一致性。( 4) 地球工程对北半球陆地气温波动的影响大于南半球陆地。地球工程情景下实施结束后的气温波动特征明显小于实施期间。地球工程对全球陆地降雨量波动特征的影响具有异质性。2020—2069 年地球工程对南( 北) 半球陆地的降雨量波动特征的影响以促进( 抑制) 作用为主; 地球工程对 2070—2099 年及地球工程实施前后降雨量波动特征的影响恰好与 2020—2069 年相反。

Perspective on influence from geoengineering project on trend and fluctuation of global land climate change and regional differences

In order to diagnose the influence from the geoengineering project on the trend and fluctuating characteristics of global land climate change，the global land climate changing characteristics and regional differences within the whole research period( 2010—2099) ，the implementation period of the geoengineering project ( 2020—2069) and after the implementation of the geoengineering project ( 2070—2099) are comparatively analyzed with the daily temperature and precipitation dataset of both the geoengineering and the non-geoengineering scenarios under BNU-ESM mode. The results show that ( 1) The consistency of spatial pattern of global land temperature changing trend is better than that of the rainfall changing trend under both the scenarios，and then the trend of the global land temperature within the three periods is mainly increased，while the trend is to be decreased under both the scenarios during the period of 2070—2099. Thus the directions of the changing trends of rainfall in different regions and sub-regions are changed during different periods by the geoengineering project. ( 2) The influence from the geoengineering project on the changing trend of the global land temperature is heterogeneous within the three periods，while the influence from the geoengineering project on the increasing and decreasing trend of temperature in 2010—2099 is the minimum，mostly between －0. 2 ℃ /( 10 a) ～ 0. 2 ℃ /( 10 a) ，of which the restraining effect on the increasing trend of temperature during 2020—2069 is the maximum and the restraining amplitudes in most of the regions are over 0. 4 ℃ /( 10 a) ，while the promoting effect on the increasing trend of temperature during 2070—2099 is the maximum with the promoting amplitudes of over 0. 4℃ /( 10a) in most of the regions. The difference of the changing trend of the global land rainfall before and after the implementation of geoengineering project is to be increased，especially obvious regional and sub-regional characteristics exhibit within the regions of the mid-low latitudes. ( 3) No fundamental change of the fluctuation of the global climate is to be caused by the geoengineering project. The fluctuating characteristics of the global land temperature and rainfall under both the scenarios are better consistent. ( 4) The influence from the geoengineering project on the land temperature fluctuation in the Northern Hemisphere is larger than that in the Southern Hemisphere. Under the geoengineering scenarios，the temperature fluctuating characteristics after the project implementation is obviously less than that during the implementation. Moreover，the influence from the geoengineering project on the fluctuating characteristics of the global rainfall is heterogeneous. The influence from the geoengineering project on the fluctuating characteristics of the land rainfall of the Southern ( Northern) Hemisphere is to be mainly dominated by promoting ( restraining) effect during 2020—2069，while the influence from the geoengineering project on the rainfall fluctuating characteristics before and after its implementation during 2070—2099 is to be just opposite to that during 2020—2069.