In this work, the sensitivity of tropical cyclone (TC) simulations over the Bay of Bengal to planetary boundary layer (PBL) physics in the WRF model is investigated. Numerical simulations are performed with WRF-ARW model using NCEP GFS data for five very severe cyclonic storms (Vardha, Hudhud, Phailin, Lehar and Thane). Five conceptually different PBL schemes (YSU, MYJ, QNSE, MYNN and BouLac) are evaluated. Results of 25 sensitivity experiments showed that PBL physics mainly affected the intensity while producing small variations in track prediction. The QNSE, followed by MYJ and BouLac, produced highly intensified storms, and MYNN produced weakly intensified storms. The YSU scheme showed better comparisons with IMD best track estimates. From the analysis of five cyclones, it is found that the YSU produced minimum errors for central pressure (−5.4, −0.8, −2.6, −5.25 hPa), maximum wind (19, 7.6, −0.96, −0.77 m/s) and track (66, 146, 182, 217 km) at 24-, 48-, 72- and 96-h forecast intervals. Analysis of various thermodynamical and dynamical parameters clearly showed that the PBL physics impacts the predictions by variation of (1) surface energy fluxes, (2) convergence, (3) inflow/outflow, (4) tangential winds, (5) vertical motion and (6) strength of the warm core and associated storm structure. A detailed analysis conducted in the case of Hudhud indicated that the PBL schemes influenced the intensity predictions through a WISHE type of feedback by the variation of convergence, radial inflow, vertical motion, and surface fluxes. While the YSU and MYNN schemes produced moderate values of radial inflow, the QNSE, MYJ and BouLac schemes produced stronger inflow. The stronger inflow, spin-up and stronger wind-induced transport of energy fluxes in the QNSE, MYJ and BouLac schemes led to a stronger convection and a higher intensification of TCs in these simulations.

中文翻译：

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边界层物理对使用 WRF 模型的孟加拉湾热带气旋模拟的影响

在这项工作中，研究了孟加拉湾热带气旋 (TC) 模拟对 WRF 模型中行星边界层 (PBL) 物理的敏感性。使用 WRF-ARW 模型使用 NCEP GFS 数据对五个非常严重的气旋风暴（Vardha、Hudhud、Phailin、Lehar 和 Thane）进行数值模拟。评估了五个概念上不同的 PBL 方案（YSU、MYJ、QNSE、MYNN 和 BouLac）。25 个灵敏度实验的结果表明，PBL 物理主要影响强度，同时在轨迹预测中产生小的变化。紧随其后的是 MYJ 和 BouLac 的 QNSE 产生了高度增强的风暴，而 MYNN 产生了强度较弱的风暴。YSU 方案显示出与 IMD 最佳轨道估计值的更好比较。通过对五个气旋的分析，发现 YSU 产生的中心压力误差最小 (-5.4, -0.8, -2.6, -5.25 hPa)，最大风速 (19, 7.6, -0.96, -0.77 m/s) 和航迹 (66, 146, 182, 217 km) 在 24-, 48-, 72- 和 96 -h 预测间隔。对各种热力学和动力学参数的分析清楚地表明，PBL 物理学通过 (1) 表面能通量、(2) 收敛、(3) 流入/流出、(4) 切向风、(5) 垂直运动和(6) 暖核强度和相关风暴结构。在 Hudhud 案例中进行的详细分析表明，PBL 方案通过会聚、径向流入、垂直运动和表面通量的变化通过 WISHE 类型的反馈影响强度预测。虽然 YSU 和 MYNN 方案产生了中等的径向流入值，但 QNSE、MYJ 和 BouLac 方案产生了更强的流入量。流入越多，