Monsoon circulation and associated rainfall add complexities in the boundary layer features over the Indian subcontinents. Besides relevant microphysical variables, the characteristics of various boundary layer parameters and their variations at differing spatial and temporal scales are investigated over Mumbai during monsoonal heavy rainfall scenarios. During the summer monsoon months (June to September) of 2014–2018, 16 heavy rainfall cases are chosen for this study. High-resolution simulation is conducted with three nested domains having a horizontal resolution of 18, 6, and 2 km with the 35 vertical levels in the advanced research WRF (WRF-ARW) model. The sensitivity experiment is carried out with seven planetary boundary layer (PBL) schemes; non-local first-order closure [Yonsei University (YSU), Asymmetric convective model, version 2 (ACM2), and Shin-Hong], local one-and-a-half order [Mellor–Yamada–Janjic (MYJ), quasi-normal scale elimination (QNSE), Bougeault–Lacarrére (BouLac), and Grenier-Bretherton-McCaa (GBM)] and five microphysics (MP) schemes [WSM6, Goddard, WDM6, Thompson, and Lin et al.]. PBL parameterization in combination with the Lin et al. scheme shows a significant impact on rainfall and dynamical and thermodynamical parameters at the surface and the upper levels. QNSE showed a relatively deeper and warmer atmospheric boundary layer compared to others to support strong upper-level divergence and high moisture content within the lower levels. Based on the results, QNSE is found to have a relatively better skill for representing the conducive environment, and Lin et al. microphysics could accommodate the same for the occurrence of the intense monsoonal rainfall events over Mumbai. The said combination is possibly effective for other coastal areas of India for better prediction of intense monsoonal rainfall episodes as well.

季风环流和相关降雨增加了印度次大陆边界层特征的复杂性。除了相关的微物理变量外，还研究了季风强降雨情景下孟买上空各种边界层参数的特征及其在不同时空尺度上的变化。在 2014-2018 年的夏季风月（6 月至 9 月）期间，本研究选择了 16 个强降雨案例。在高级研究 WRF (WRF-ARW) 模型中，对水平分辨率为 18、6 和 2 公里的三个嵌套域进行了高分辨率模拟，垂直水平为 35。敏感性实验采用七种行星边界层（PBL）方案进行；非局部一阶闭包 [延世大学 (YSU)，非对称对流模型，版本 2 (ACM2)，和 Shin-Hong]、局部一阶半 [Mellor-Yamada-Janjic (MYJ)、准正态尺度消除 (QNSE)、Bougeault-Lacarrére (BouLac) 和 Grenier-Bretherton-McCaa (GBM) ] 和五个微物理 (MP) 方案 [WSM6、Goddard、WDM6、Thompson 和 Lin 等人]。PBL 参数化结合 Lin 等人。方案显示对地表和高层的降雨和动力和热力学参数有显着影响。与其他大气边界层相比，QNSE 显示出相对更深和更温暖的大气边界层，以支持强烈的上层发散和较低层内的高水分含量。根据结果​​，发现 QNSE 在表示有利环境方面具有相对更好的技能，Lin 等人。微观物理学可以适应孟买上空强烈季风降雨事件的发生。所述组合对于印度其他沿海地区也可能有效，以更好地预测强季风降雨事件。