Abstract In the present study, mean rainfall for the months of June-July-August-September (JJAS) during summer monsoon is simulated over India and its adjoining regions for a period between 1982 and 2006. The study was carried out using Regional Climate Model (RegCM) version 4.6 at a resolution of 25 km. The simulated mean JJAS monsoon rainfall was validated against the observational IMD data. Comparison of JJAS seasonal mean summer rainfall for the first decade 1982–1991, with the later decade 1997–2006 indicate that the intensity of rainfall increases over Indian land-mass during the later decade under the forced conditions of Era-Interim. The observed JJAS mean rainfall indicates two maximum rainfall areas i.e. the Western Ghats and the Himalayan region. A significant bias is observed in the central and Jammu and Kashmir (J&K) region. The JJAS mean seasonal surface air temperature distribution at 0.25 × 0.25-degree grids resolution shows a decreasing trend of temperature over the Indian landmass.

中文翻译：

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印度夏季风的临时强迫模拟

摘要 本研究模拟了 1982 年至 2006 年印度及其邻近地区夏季风期间 6-7-8-9 月 (JJAS) 月份的平均降雨量。该研究是使用区域气候模式进行的。 (RegCM) 4.6 版，分辨率为 25 公里。模拟的平均 JJAS 季风降雨量根据 IMD 观测数据进行了验证。JJAS 1982-1991 前十年与后十年1997-2006 的季节性平均夏季降雨量的比较表明，在Era-Interim 强迫条件下，后十年印度陆地上的降雨强度增加。观测到的 JJAS 平均降雨量表明有两个最大降雨区，即西高止山脉和喜马拉雅地区。在中部和查谟和克什米尔 (J&K) 地区观察到显着的偏差。