Modeling study of the impact of complex terrain on the surface energy and hydrology over the Tibetan Plateau
Modeling study of the impact of complex terrain on the surface energy and hydrology over the Tibetan Plateau
复制标题
青藏高原复杂地形对地表能量和水文影响的模拟研究
DOI：
10.1007/s00382-019-04966-z
复制
发表时间：
2019-12-01
期刊：
影响因子：
4.6
通讯作者：
Lu, Daren
中科院分区：
文献类型：
--
作者：
Fan, Xuehua;Gu, Yu;Lu, Daren
利用第四版全球社区气候系统模式(CCSM4)，结合三维辐射传输(RT)参数，研究了复杂地形对青藏高原(TP)太阳能量分布和地表水文的长期影响。我们考察了CCSM4三维RT参数化的结果和CCSM4平面并行RT格式的结果之间的差异。在1月(冬季)，由于三维阴影效应，地表净太阳通量(FSNS)在山谷和山脉北坡上表现出负偏差，特别是在TP的北缘。1月份FSNS的正偏差出现在山脉南坡和山顶，那里截获了更多的太阳通量。总云量和雪水当量(SWE)的偏差表现出与FSNS相反的模式。在春季，由于三维山脉效应，SWE减小，这种影响的大小取决于地形海拔高度。4月份SWE比TP减少1-1700万mm，其中海拔3.5-4.5m的SWE下降幅度最大。除5月和12月外，全年降水都存在负偏差，而且它们遵循总云量偏差的季节变化。4月份，由于向下太阳辐射增加导致的早期(3月)积雪融化，海拔3.5-4.5公里处的液体径流总量增加。大多数气候模式中的平面平行假设可能导致地表能量和SWE对TP的偏离，从而可能导致TP及其下游的液体径流和河流水资源的偏差。
The long-term effects of complex terrain on solar energy distributions and surface hydrology over the Tibetan Plateau (TP) are investigated using the 4th version of the global Community Climate System Model (CCSM4) coupled with a 3-D radiative transfer (RT) parameterization. We examine the differences between the results from CCSM4 with the 3-D RT parameterization and the results from CCSM4 with the plane-parallel RT scheme. In January (winter), the net surface solar flux (FSNS) displays negative deviations over valleys and the north slopes of mountains, especially in the northern margin of the TP, as a result of the 3-D shadow effect. Positive deviations in FSNS in January are found over the south slopes of mountains and over mountain tops, where more solar flux is intercepted. The deviations in total cloud fraction and snow water equivalent (SWE) exhibit patterns opposite to that of FSNS. The SWE decreases due to the 3-D mountain effect in spring and the magnitude of this effect depends on the terrain elevations. The SWE is reduced by 1–17 mm over the TP in April, with the largest decrease in SWE at an elevation of 3.5–4.5 km. Negative deviations in precipitation are found throughout the year, except in May and December, and they follow the seasonal variations in the deviations in total cloud fraction. The total liquid runoff at 3.5–4.5 km elevation increases in April due to earlier (March) snowmelt caused by increased downward solar radiation. The possible deviations in surface energy and SWE over the TP, caused by plane-parallel assumption in most climate models may result in biases in the liquid runoff and the river water resources over the TP and downstream.