Differences in the raindrop size distributions of pre-monsoon thunderstorms and tropical cyclones observed over eastern India

IF 4.4 2区地球科学 Q1 METEOROLOGY & ATMOSPHERIC SCIENCES

Atmospheric Research Pub Date : 2025-09-01 DOI:10.1016/j.atmosres.2025.108456

Anuj Shrivastava , Balaji Kumar Seela , Bhishma Tyagi , Pay-Liam Lin

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引用次数: 0

Abstract

Investigations on the raindrop size distributions (RSDs) are essential for understanding the dynamical and microphysical processes contributing to precipitation. Empirical relationships derived from RSD parameters, like radar reflectivity–rainfall rate (Z–R), mass-weighted mean diameter–rainfall rate (D_m–R), shape–slope (μ–Ʌ), and normalized intercept parameter–rainfall rate (log₁₀N_w–R) relationships, can enhance the rainfall estimation, and cloud modeling simulations. In the present study, four years (2018–2021) measurements of a Laser Precipitation Monitor (LPM; Thies) disdrometer installed at the National Institute of Technology Rourkela, India, are used to investigate the RSD characteristics of thunderstorms (TSs) and tropical cyclones (TCs) observed during pre-monsoon (March–May) season. Along with the disdrometer data, auxiliary parameters like convective available potential energy (CAPE), convective inhibition (CIN), total column water vapor (WV), vertical profiles of temperature (T) and relative humidity (RH) from reanalysis data sets of ECMWF (European Centre for Medium-Range Weather Forecasts) fifth-generation reanalysis (ERA5) are also used in this study. TCs have dominant small-sized raindrops, whereas moderate and large-sized raindrops predominate in TSs. Diurnal variation of RSD indicates that raindrop sizes during TCs are limited to 4.5 mm. The mean values of R, Z, D_m, μ, and liquid water content (W) are maximum during the TSs and the normalized intercept parameter (log₁₀N_w) and slope parameter (Ʌ) are maximized during the TCs. The average RSD indicated significant variations between TSs and TCs precipitation with a significant difference in Z–R, D_m–R, μ–Ʌ, log₁₀N_w–R relationships. The Z–R relationships during the TSs and TCs are Z = 543.22R^1.46 and Z = 291.3R^1.31, respectively. The diurnal variations in Z–R coefficient ‘A' and exponent ‘b’ values are associated with sizeable diurnal variations of CAPE and CIN.

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在印度东部观测到的季风前雷暴和热带气旋的雨滴大小分布差异

雨滴大小分布（rsd）的研究对于理解降水的动力和微物理过程至关重要。由RSD参数导出的经验关系，如雷达反射率-降雨率（Z-R）、质量加权平均直径-降雨率（Dm-R）、形状-斜率（μ -Ʌ）和归一化截距参数-降雨率（log10Nw-R）关系，可以增强降雨估计和云模拟模拟。在本研究中，使用安装在印度rourkla国立理工学院的激光降水监测仪（LPM; Thies）的四年（2018-2021）测量数据，研究了季风前（3 - 5月）季节观测到的雷暴（TSs）和热带气旋（TCs）的RSD特征。本研究利用欧洲中期天气预报中心（ECMWF）第五代再分析（ERA5）数据集的对流有效势能（CAPE）、对流抑制（CIN）、总水柱水汽（WV）、温度(T)和相对湿度（RH）垂直剖面图等辅助参数，与分差仪数据相结合。TCs以小雨滴为主，TCs以中、大雨滴为主。RSD的日变化表明，tc期间的雨滴大小限制在4.5 mm。R、Z、Dm、μ和液态水含量(W)的平均值在TSs期间最大，归一化截距参数（log10Nw）和斜率参数（Ʌ）在TCs期间最大。TSs和TCs降水量的平均RSD差异显著，Z-R、Dm-R、μ -Ʌ、log10Nw-R关系差异显著。TSs和TCs的Z - r关系分别为Z = 543.22R1.46和Z = 291.3R1.31。Z-R系数“A”和指数“b”值的日变化与CAPE和CIN的较大日变化有关。

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来源期刊

Atmospheric Research 地学-气象与大气科学

CiteScore

9.40

自引率

10.90%

发文量

460

审稿时长

47 days

期刊介绍： The journal publishes scientific papers (research papers, review articles, letters and notes) dealing with the part of the atmosphere where meteorological events occur. Attention is given to all processes extending from the earth surface to the tropopause, but special emphasis continues to be devoted to the physics of clouds, mesoscale meteorology and air pollution, i.e. atmospheric aerosols; microphysical processes; cloud dynamics and thermodynamics; numerical simulation, climatology, climate change and weather modification.