【摘要】 文中对陆面过程模式 (BATS)进行了改进 ,改进后的模式能较好地模拟地表物理量的年、季和日变化 ,它有两方面的特点 :采用热扩散方程模拟 7层土壤温度 ,模拟的温度可与实测值进行比较 ;在BATS的地表径流方案中 ,考虑了空间不均匀性的一般地表径流 (GVIC)过程 ,研究结果表明 :⑴模式能很好地模拟各层土壤温度的年、季和日变化。冬季土壤温度下层高于上层 ,而在夏季上层高于下层 ,这种上下层温度的转换时间大约在 4和 10月份 ,这与实测土壤温度的年变化非常一致。较为准确地模拟了各层土壤温度日变化的时滞效应。⑵用南京和武汉站的资料 ,将BATS地表径流方案模拟的地表水分分量与GVIC方案进行比较 ,BATS地表径流方案模拟的地表水分分量 ,与总水量的平衡相差较大 ,而GVIC模拟的效果相对较好 ,地表总水量基本上与降水总量达到了平衡更多还原

【Abstract】 The energy and hydrological balance are the physical basis of land surface process. There are some description limitations about heat diffusion between the up and down soil layers. Besides, many surface models fix the bottom soil temperature. In fact, the soil temperature of 320 cm has still annual variation according to the observation. This variation impacts obviously that of upper layer. Secondly, land process model has also some problems about hydrological balance. There are many uncertainties such as runoff, evaporation calculation due to the short of the completely observation data of the surface hydrological components. So, this paper suggested a seven-layer soil model in terms of BATS framework, which can represent the horizontal inhomogeneity of surface runoff. First step, the paper established parameterized formul of the clean and cloudy global radiation and atmospheric long-wave radiation according to the functional relationship between atmospheric long-wave radiation and absorption medium in atmosphere. Second step, the seven-layer soil model with 0, 5, 10, 20, 40, 80, 160 cm and 320 cm modifies the two-layer soil model of BATS. The soil heat diffusion equation was numerically resolved by the two-step difference method, where 320 cm-bottom soil temperature was represented by cosine annual variation. The simulating soil temperature was verified by meteorological data. Final step, BATS runoff scheme was modified by GVIC with the horizontal infiltration imhomogeneity whose rationality and reliability were verified by surface hydrological balance. The results show that the simulating global and net radiations are completely agreed with the observed value, even in cloudy sky. The simulated total of heat components, such as sensitive heat, latent heat and soil heat flux are equal to the observed net radiation, which meet with the surface heat balance equation. The seven-layer soil model improved significantly the soil temperature simulation. It modeled the soil temperature annual variation, and showed that the soil temperature of the down layer was higher than that of the up layer in winter, and the reverse was in summer. The annual variation phase of the soil temperature of the down layer is obviously later than the phase of the up layer. The soil played a smooth role in the short-term fluctuation of soil temperature in heat conductive process. The characteristics are consistent with the observation, and cannot be simulated by two-soil-layer model of BATS. The calculation of surface runoff plays an important role in the simulation of land surface hydrological balance. The results showed that the BATS total of surface hydrological components cannot balanced with the precipitation. GVIC, a runoff scheme that this paper suggested, simulated the components that almost reach the hydrological balance with the precipitation. It found that the soil infiltration of BATS was on the low side by the analysis of the difference between these two runoff schemes. This soil infiltration may result untruthful strong variation of short-term runoff. The reasons, which bring the significantly difference between these two runoff schemes, are theoretically as follows: 1. The runoff of BATS, when the rainfall is greater than the evaporation, must be created. In fact, it isnot always true. Because the slight rainfall almost all infiltrate and can’t create runoff. So the simulated runoff by BATS is on the high side. For example, the simulated runoff by BATS is 85 mm more than that by GVIC, so that the total of components is over 81mm more than the precipitation in Nanjing Station. 2. On the other hand, all precipitation will not penetrate any more for BATS when the soil moisture reaches the field capacity at the heavy precipitation, for example, Wuhan 1998. 3. Finally, the BATS didnot consider the horizontal imhomogenity. In fact, it is an important factor for the surface hydrological calculation.更多还原