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Energy partitioning and environmental influence factors in different vegetation types in the GEWEX Asian Monsoon Experiment

Liu, Fengshan, Tao, Fulu, Li, Shenggong, Zhang, Shuai, Xiao, Dengpan, Wang, Meng
Frontiers of earth science 2014 v.8 no.4 pp. 582-594
agricultural land, energy balance, environmental factors, forests, grasses, grasslands, heat transfer, monsoon season, soil water, summer, temperature, vapor pressure, water vapor, China, Mongolia, Russia, Thailand
Environmental influences upon energy balance in areas of different vegetation types (i.e., forest at Kog-Ma in Thailand and at Yakutsk in Russia, grassland at Amdo in Chinese Tibet and at Arvaikheer in Mongolia, and mixed farmland at Tak in Thailand) in the GEWEX Asian Monsoon Experiment were investigated. The sites we investigated are geographically and climatologically different; and consequently had quite large variations in temperature (T), water vapor pressure deficit (VPD), soil moisture (SM), and precipitation (PPT). During May-October, the net radiation flux (Rₙ) (in W·m⁻²) was 406.21 at Tak, 365.57 at Kog-Ma, 390.97 at Amdo, 316.65 at Arvaikheer, and 287.10 at Yakutsk. During the growing period, the Rₙpartitioned into latent heat flux (λE/Rₙ) was greater than that partitioned into sensible heat flux (H/Rₙ) at Tak and at Kog-Ma. In contrast, λE/Rₙwas lower than H/Rₙat Arvaikheer, H/Rₙwas less than λE/Rₙbetween DOY 149 and DOY 270 at Amdo, and between DOY 165 and DOY 235 at Yakutsk. The Rₙpartitioned into ground heat flux was generally less than 0.15. The short-wave albedo was 0.12, 0.18, and 0.20 at the forest, mixed land, and grass sites, respectively.At an hourly scale, energy partitions had no correlation with environmental factors, based on average summer halfhourly values. At a seasonal scale energy partitions were linearly correlated (usually p<0.05) with T, VPD, and SM. The λE/Rₙincreased with increases in SM, T, and VPD at forest areas. At mixed farmlands, λE/Rₙgenerally had positive correlations with SM, T, and VPD, but was restrained at extremely high values of VPD and T. At grasslands, λE/Rₙwas enhanced with increases of SM and T, but was decreased with VPD.