Abstract In this study, we provide a comprehensive analysis of spatio-temporal distribution of extreme rainfall of different intensities (heavy, very heavy and extremely heavy) as well as wet spell over the Indian landmass during monsoon (June–August) of 2016–2018 through satellite observations. Moreover, there were ~ 35 extreme rainfall events during the study period, which has accumulated rainfall > 120 mm hr−1 and the first 12 events were identified (having highest amount of accumulated rainfall in a day out of 35 events) for our study. The event locations were so selected where there is not any point observations [automatic weather station (AWS) or automatic rain gauge (ARG)] at the site of extreme rainfall events, not even within 50 km radius of the event site or if any AWS/ARG site is present but were unrecorded or unreported during the time of extreme rainfall event. 70% of the extreme rainfall events (convective storms) occurred in the afternoon where 75% of the events indicates > 150 mm hr−1 accumulated rainfall and the rest 25% shows the accumulation rate to be > 120 mm hr−1. The factors influencing the extreme rainfall events to occur are obtained to be increased instability parameters (convective available potential energy, K-Index, Total Total's index), meteorological, thermodynamic and dynamical parameters (upper and lower level temperature gradient difference, vertical difference of equivalent potential temperature at 850 and 500 hPa, moisture flux convergence) and decreased temperature saturation deficit. The convective growth started initiating 6–7 h before the occurrence of extreme rainfall, indicating the favourable condition for severe convection. Furthermore, if the diurnal relative humidity range is maximum and there is a sharp increase in specific humidity at a location, there is a maximum probability of extreme rainfall after 5–6 h at that location. Both the Global Forecast System (GFS) and NCMRWF Unified Model (NCUM) captured the extreme rainfall events well for the year 2018 over the Indian region.

中文翻译：

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使用卫星观测、再分析和模型预测解读印度陆地上的极端降雨情景：案例研究

摘要 在本研究中，我们综合分析了 2016 年至 2018 年季风期间（6 月至 8 月）印度陆地上不同强度（强、特强和特强）的极端降雨的时空分布和湿润期。通过卫星观测。此外，在研究期间发生了约 35 次极端降雨事件，累积降雨量 > 120 mm hr-1，我们的研究确定了前 12 次事件（35 次事件中一天累积降雨量最高）。事件地点选择在极端降雨事件现场没有任何点观测[自动气象站 (AWS) 或自动雨量计 (ARG)] 的地方，甚至不在事件地点 50 公里半径内，或者如果存在任何 AWS/ARG 站点但在极端降雨事件期间未记录或未报告。70% 的极端降雨事件（对流风暴）发生在下午，其中 75% 的事件表明累积降雨量 > 150 mm hr−1，其余 25% 表明累积速率 > 120 mm hr−1。影响极端降雨事件发生的因素有增加的不稳定性参数（对流可用势能、K指数、总总指数）、气象、热力学和动力参数（上下层温度梯度差、等效垂直差） 850 和 500 hPa 的潜在温度，水分通量收敛）和降低的温度饱和赤字。对流增长在极端降雨发生前 6~7 h 开始，表明存在强对流的有利条件。此外，如果昼夜相对湿度范围最大，并且某个位置的比湿度急剧增加，则该位置 5-6 小时后出现极端降雨的可能性最大。全球预报系统 (GFS) 和 NCMRWF 统一模型 (NCUM) 都很好地捕捉了 2018 年印度地区的极端降雨事件。