Mumbai, the compact megacity, the economic capital of India, is highly vulnerable to severe weather conditions, particularly related to the rainfall phenomenon. A MESO-scale rain gauge NETwork (MESONET) comprises 131 rain gauges scattered over the Mumbai metropolitan region is established to have instantaneous rainfall information. A real-time web-based rainfall data portal is set up as a public informative/awareness system that would help the public to cope with unanticipated situations caused by massive rainfall events. In this work, we provide the rationale of Mumbai MESONET and preliminary results from the observations during July–October 2019.

High-resolution MESONET rainfall data are analyzed to examine the mean and associated small-scale spatiotemporal variability of rainfall over Mumbai. The results depict that the maximum contribution of rainfall is from low to moderate and heavy rainfall events. The prevalent occurrence of prolonged rainfall events of moderate to high intensity during mid-night and early morning hours is attributed to the diurnal variability of events duration. It is observed that heavy rainfall events (64–124 mm/day) occur at a sub-daily scale. Correlogram analysis of rainfall further reveals the good spatial coherence in the spatial variability of rainfall even at sub-daily scales.

孟买是印度的经济首都，这座紧凑的大都市极易受到恶劣天气条件的影响，尤其是与降雨现象有关。建立了一个 MESO 尺度雨量计网络 (MESONET)，它由分布在孟买大都市区的 131 个雨量计组成，以获取瞬时降雨信息。建立了一个基于网络的实时降雨数据门户，作为一个公共信息/意识系统，帮助公众应对由大规模降雨事件引起的意外情况。在这项工作中，我们提供了孟买 MESONET 的基本原理和 2019 年 7 月至 10 月期间观测的初步结果。

分析高分辨率 MESONET 降雨数据以检查孟买降雨的平均和相关小尺度时空变异。结果表明降雨的最大贡献来自低到中和强降雨事件。在午夜和清晨时段普遍发生中到高强度的长时间降雨事件，这归因于事件持续时间的昼夜变化。据观察，强降雨事件（64-124 毫米/天）发生在次日尺度。降雨相关图分析进一步揭示了降雨的空间变异性，即使在亚日尺度上也具有良好的空间一致性。