Modeling Analysis to Energy Closure Problem at a GAME/Tibet Site
kun YANG (1), Toshio Koike (2)
(1) Telecommunications Advancement Organization of Japan
(2) University of Tokyo
Based on collected data at station Amdo of GAME/Tibet during intensive observing period in 1998, energy balance at ground surface is reexamined through modeling analysis. (1) Surface soil heat flux is calculated through thermal diffuse equation (TDE) with very fine resolution.The numerical solution shows that heat flux into soil surface is much greater than that at 10cm depth, so heat flux into soil surface mainly stores in the top 10cm layer. and The simuation also shows that heat flux at 10cm is greater than measurement. (2)Sensible heat flux and evaporation are simulated with a simple biosphere model SiB2. In order to better estimate turbulent heat fluxes, soil moisture is provided to SiB2 as input data, rather than as prognostic variables. The SIB2 simulation indicates surface temperature from SiB2 is agreeable to that derived from upward long-wave radiation, heat flux into soil surface from SIB2 is close to that from TDE solution, and sensible heat flux agrees well with that measured by eddy-correlation method, while latent heat flux is smaller than measurement. When observed net radiation, sensible heat flux, latent heat flux and surface soil heat flux are used for energy budget check, a big energy imbalance (daily average 70w/m2) is found. However, if the latent heat flux from SiB2 simulation instead of observed one is used to evaluate energy budget,the imbalance energy at ground surface decreases dramatically (daily average 7w/m2). The study suggests that soil heat flux and latent heat flux play very crucial roles in surface energy budget and they may be under-measured in GAME/Tibet field works at Amdo station.
Submittal Information
Name :
Date :
Kun Yang, Dr.
28-May-01-16:31:52
Organization :
Theme :
Telecommunications Advancement Organization of Japan
Theme 1
Address :
Presentation :
River lab., Dept. of Civil Engineering, University of Tokyo, Hongo7-3-1, Bunkyo-ku, Tokyo 113-8656
