H31F-1479
Evapotranspiration and Surface Water balance in China
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Han Zheng1, Guirui Yu2, Qiufeng Wang2, Xianjin Zhu2, Huimin Wang1, Peili Shi2, Fenghua Zhao2, Yiping Zhang3,4, Junhua Yan4, Yingnian Li5, Liang Zhao5, Junhui Zhang6 and Yanfen Wang7, (1)Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China, (2)IGSNRR Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing, China, (3)Key Lab of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, ChinaKey Lab of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, China, (4)South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China, (5)Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China, (6)Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China, (7)University of Chinese Academy of Sciences, Beijing, China
Abstract:
Evapotranspiration (ET) is the second largest component of land surface hydrological cycle, behind only precipitation. Globally, over 60% of precipitation is returned to atmosphere through evaporation and transpiration. However, owing to lacking of long-term direct measurements of ET, ET is often assessed using indirect measures (e.g., pan evaporation, residual between precipitation and runoff), which partly makes ET the most problematic term in the water budget. Eddy covariance (EC) method can directly measure ET on a continuous and long-term basis and is preferred among meteorologists and ecologists. Since 2002, China has utilized EC method to measure ET of major vegetation types in key regions and data from over 50 sites have been collected. Therefore, by synthesizing ecosystem-level water flux data observed by eddy covariance method in China, we analyzed the ET and surface water balance variations in China. Results showed that both the climate and vegetation effects were significant on ET variation, while the climate and vegetation interaction effects were not significant. Similarly, surface water balance (the ratio of ET to precipitation) also showed significant differences among different vegetation and climate types. Besides, we also compared several published global ET products over China. Results showed that, although their predictions for all the sites were significantly correlated with the EC-observations over China, there were huge departures on the magnitude of ET, which is because very few site measurements from China have been applied in verifying the effectiveness of global ET products.
