The Simulation Research Of Surface Energy Balance Based On The Simplified Biosphere Mode2(SiB2)

Land surface processes impact weather and climate mainly through turbulence, momentum, heat, water vapor and carbon dioxide exchanges between the ground and atmosphere. Climate simulations are especially sensitive to the seasonal and diuRnal variations in surface partitioning of available energy into sensible and latent heat fluxes. The land surface is an important component of the climate system.To evaluate the performance of land surface models in energy partitioning simulation, the original and modified versions of Simple Biosphere Model2are applied to simulate the surface radiation balance, turbulent energy budget, and soil temperature and moisture over a PRL tank exercise field in suburban Beijing from22July through5August2010and Naqu station in Tibetan Plateau from15July through15September2008. Parameters, the initial values and forced values (short-wave solar radiation, atmospheric long-wave radiation, vapor pressure, air temperature, horizontal wind speed, and precipitation.) are obtained from the direct measurements. Simulated results were compared against the direct measurements. Results show that:(1) The modified SiB2improved the simulation of net radiation. But it didn’t improve the simulation of upword short-wave radiation.(2) The simulation of yangfang showed that:The modified SiB2improved the simulation of sensible heat and latent heat fluxes. Original and modified SiB2underestimated the simulation results of sensible heat flux by8.88%and0.64%respectively. And underestimated latent heat flux by39.96%and36.98%respectively. The modified SiB2improved the simulation of sensible heat flux in the nighttime. But the simulation of naqu showed that:modified SiB2don’t improve the simulation results of sensible heat flux. Original and modified SiB2underestimated the simulation results of sensible heat flux by27.28%and27.81%respectively. Original SiB2underestimated the latent heat flux by13.15%, while modified SiB2underestimated the latent heat flux by13.49%. Modified SiB2improved the simulation result of latent heat flux in the nighttime.(3) During the simulation period, the simulation in both Naqu and yangfang showed that: modified SiB2where soil thermal conductivity was updated better simulated the soil temperature (include soil surface temperature).