Permafrost

temperature are apparent in observed near-surface lapse rates and inversions. To evaluate the
effect of vegetation on ground surface temperature, several heat-transfer coefficients were
estimated, including land cover specific thermal diffusivity and empirical n-factors. The results
of this study will be used to refine spatial temperature fields in complex terrain and to improve
land cover parameterizations currently used in permafrost and climate models.
Key words: air temperature, soil temperature, Alaska, tundra vegetation, permafrost
Modeling the surface energy fluxes and ground thermal regime at Lhasa,
Tibet
Feng Ling 1 , Ting-jun Zhang 2 , Guo-ping Li 3
(1. Software School, Zhaoqing University, Zhaoqing, Guangdong 526061, China; 2 .National Snow
and Ice Data Center, CIRES, University of Colorado, Boulder, Colorado 80309, U.S.A; 3.Department
of Earth and Environment Science, Chengdu University of Information Technology, Chengdu, Sichuan
610072, China
Abstract: Ground surface energy balance in cold regions is a complex function of seasonal
snow cover, vegetation, atmospheric radiation, surface moisture content, and atmosphere
temperature. Thus, the accurate approach for describing ground surface temperature and ground
thermal regime should be through the physically-based models which account for the relevant
processes occurring within, and at the boundaries of permafrost, snow, and atmospheric
components of the natural system. This study models the surface energy balance components
and ground temperature at different depths at Lhasa, Tibet, by using a surface energy balance
approach based heat transfer model. The influence of unfrozen water on the ground thermal
regime was considered, and the effect of snow was included in the model by extending the heat
conduction solution into the snow layer and computing the surface heat balance and the snow
surface temperature. The baseline inputs for the meteorological characteristics are observed
data at a weather station at Lhasa on the Tibetan Plateau during 1998. The net solar radiation,
net longwave radiation, sensitive heat flux, latent heat flux and conductive heat flux were
simulated. The surface and ground soil temperature at different depths also were calculated.
Key words: Surface energy balance; ground thermal regime; finite difference method;
Qinghai-Tibet Plateau
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