作 者：
陈之光;张翔;刘晓琴;张立锋;唐艳鸿;杜明远;古松
关键词：
晴空指数;净生态系统交换量;光量子通量密度;饱和水汽压差;生态系统呼吸
摘 要：
青藏高原是地球上接收太阳辐射能最多的地区之一,具有世界上最高的高寒草甸生态系统,对区域乃至全球碳循环起着重要作用.为了探究太阳辐射变化对高寒草甸生态系统碳动态的影响,本研究利用涡度相关技术和微气象观测系统对高寒草甸生态系统CO_2净交换(NEE)、太阳总辐射、散射辐射及其相关环境要素进行观测;根据晴空指数(CI,到达地面的太阳辐射与大气上界太阳辐射的比值)将天空状况划分为晴天(CI≥0.7)、多云(0.30.6 k Pa时,NEE随VPD的升高呈缓慢下降趋势,说明相对较高的VPD抑制了生态系统的光合作用.晴天的强辐射并不能促进青藏高原高寒草甸的碳吸收能力,而晴空指数在0.6~0.7范围的多云天气最有利于生态系统碳固定.
译 名：
Responses of net ecosystem carbon exchange to diffuse radiation in an alpine meadow on the Qinghai-Tibetan Plateau,China
作 者：
CHEN Zhi-guang;ZHANG Xiang;LIU Xiao-qin;ZHANG Li-feng;TANG Yan-hong;DU Ming-yuan;GU Song;College of Life Sciences,Nankai University;College of Urban and Environmental Sciences,Peking University;National Institute for Agro-Environmental Science;
单 位：
CHEN Zhi-guang%ZHANG Xiang%LIU Xiao-qin%ZHANG Li-feng%TANG Yan-hong%DU Ming-yuan%GU Song%College of Life Sciences,Nankai University%College of Urban and Environmental Sciences,Peking University%National Institute for Agro-Environmental Science
关键词：
clearness index;;net ecosystem exchange;;photosynthetic photon flux density;;vapor pressure deficit;;ecosystem respiration
摘 要：
Qinghai-Tibetan Plateau,one of the regions on the earth that receives the most solar radiation,is the world's highest alpine meadow ecosystem,with significance to regional and global carbon cycles. To examine the effects of solar radiation on ecosystem carbon dynamics in an alpine meadow,the net ecosystem CO_2 exchange( NEE),solar radiation,diffuse radiation,and related environmental variables were measured using eddy-covariance technique and micro-meteorological system. Sky conditions were divided into three categories of clear days( CI ≥ 0. 7),cloudy days( 0.315 ℃. Under clear sky day conditions,Re increased with increasing CI due to the increases of air temperature,with negative effects on NEE.NEE increased with the increases of VPD up to 0. 6 k Pa,then slowly decreased when VPD > 0. 6 kPa,illustrating that NEE was reduced due to the relatively high VPD. Our results suggested that strong solar radiation on clear days would not increase carbon uptake capacity of alpine meadow,while cloudy days with clearness index of 0.6-0.7 would help increase carbon sequestration on the Qinghai-Tibetan Plateau.
