Orographic enhancement of rainfall over the Congo Basin
Orographic enhancement of rainfall over the Congo Basin
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DOI：
10.1002/asl.1079
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发表时间：
2022-03
影响因子：
3
通讯作者：
A. Raghavendra;G. Xia;Liming Zhou;Yan Jiang
中科院分区：
文献类型：
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作者：
A. Raghavendra;G. Xia;Liming Zhou;Yan Jiang
位于赤道非洲中部的刚果雨林是地球仪的一个重要但尚未得到充分研究的部分，周围环绕着复杂的地形特征。对降水过程如中尺度对流动力学的原始认识放大了刚果水文循环未来气候预测的不确定性。此外，地形是对流和降水的重要强迫，气候模式对地形的影响解决得很差，在刚果的概念化也很差。为了解决这一知识缺口，扰动地形强迫实验进行了使用天气研究和预报（WRF）中尺度数值模式在高分辨率对流允许模式设置。该模型模拟了2014年11月的选定日期。在本文分析的案例研究中，控制运行中模拟的雷暴和降雨与卫星获得的亮温和降雨数据进行了比较。本案例研究的结果表明，东非高地高度增加的动力影响是对流层低层热带东风的阻塞。低对流层纬向风的减弱增加了刚果盆地上空的风切变，导致传播速度较慢，更强烈的中尺度对流系统，降雨量增加。
The Congo rainforest located in central equatorial Africa is an important, yet understudied part of the globe surrounded by complex orographic features. A primitive understanding of precipitation processes such as mesoscale convective dynamics magnifies uncertainties in the future climate projections of the hydrological cycle over the Congo. Furthermore, the effects of orography, which is an important forcing for convection and precipitation, are poorly resolved by climate models, and ill‐conceptualized over the Congo. To address this knowledge gap, perturbed orographic forcing experiments are conducted using the Weather Research and Forecasting (WRF) mesoscale numerical model in a high‐resolution convection‐permitting model setup. The model simulated selected dates in November 2014. The thunderstorms and rainfall simulated in the control run for the case study analyzed in this article compared reasonably well to satellite‐derived brightness temperature and rainfall data. The results from this case study show that the dynamical impact of increasing the height of the East African Highlands is the blocking of the lower‐tropospheric tropical easterlies. This weakening of the lower‐tropospheric zonal winds increases the windshear over the Congo Basin resulting in slower propagating, more intense mesoscale convective systems with enhanced rainfall.