青藏高原冷季积雪对后期暖季植被的影响  

Effects of cold-season snow on late warm-season vegetation on the Tibetan Plateau

作　　者：王园香[1] WANG Yuanxiang(National Satellite Meteorological Centre,Beijing 100081,China)

机构地区：[1]国家卫星气象中心,北京100081

出　　处：《草业科学》2021年第3期480-488,共9页Pratacultural Science

基　　金：公益性行业(气象)科研专项“青藏高原气候和生态环境要素数据库的建立(GYHY201306017)”;国家自然科学基金(41775084)。

摘　　要：研究青藏高原冷季积雪对后期暖季植被的影响和机制,有助于生态系统保护和应对全球变化适应性对策的制定。使用回归、相关和合成分析法以及1996−2013年积雪、归一化植被指数、国家环境预报中心大气再分析资料降水量融合分析降水量资料,研究了青藏高原冷季(1月−3月)积雪对后期暖季(4月−9月)植被的影响。结果表明,当高原冷季积雪异常偏多,后期暖季植被也异常偏多,这种正相关关系是通过大气环流将积雪和植被联系到一起的。当高原冷季积雪偏多,暖季东亚夏季风减弱,太平洋副热带高压加强西移并影响高原东部地区,该地暖季地面温度升高,积雪融化,土壤湿度增大,日照增加,降水量减少,前4个要素均对植被生长起促进作用。特别是积雪消融可以有效补给到土壤中,增加土壤水份,有利于植被返青及其前期生长,而降水量更是土壤水份的主要补给来源,但由于在植被生长的旺盛期,降水量往往较为充沛且能够满足植被生长的需求,同期归一化植被指数也恰好是一年中最高的,此时降水量过多可能导致植被生长受到抑制,降水量略减少反而可能会促进植被的生长。Studying the effects of cold-season snow on warm-season vegetation and understanding the underlying mechanisms may help conserving ecosystems and implementing effective steps to counteract climate change on the Tibetan Plateau(TP).Using regression,correlation,and composition analysis as well as data on fractional snow cover(FSC),normalized difference vegetation index(NDVI),National centers for Environmental Prediction(NCEP)and climate Prediction Center Merged Analysis of Precipitation(CMAP),the relationships between cold-season snow and warm-season vegetation on the TP were investigated.The results showed that when cold-season snow increased,warm-season vegetation also increased on the TP,and vice versa.This relationship is supported by background atmospheric circulation.When the amount of snow in the cold season is untypically large,the eastern Asia summer monsoon weakens,and the Pacific subtropical high increases,moves westward and affects the eastern TP during the warm season.Such an atypical high during the warm season results in higher surface temperatures,snow melting,increased soil moisture,increased solar radiation,and decreased precipitation,the first four phenomenona of which favor vegetation growth.Especially,melting snow provides considerable amounts of water to the soil,which favors vegetation rejuvenation and early growth.Precipitation is the main source of soil water,and it is typically abundant and meets the requirements of vegetation growth during warm seaso however,NDVI is highest during the warm season,and excessive precipitation may result in reduced vegetation growth,thus a slight decrease in precipitation may promote vegetation growth.

关 键 词：东亚夏季风 消融 降水量 影响和机制 回归 合成 

分 类 号：S812[农业科学—草业科学]