Precipitation in Nepal between 1987 and 1996
Precipitation in Nepal between 1987 and 1996
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DOI：
10.1002/joc.1492
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发表时间：
2007-11-15
期刊：
影响因子：
--
通讯作者：
Vaidya, Bijaya Kumar
中科院分区：
文献类型：
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作者：
Ichiyanagi, Kimpei;Yamanaka, Manabu D.;Vaidya, Bijaya Kumar
从1987年至1996年的雨量站数据被用来调查空间和时间的变化，在尼泊尔的月降水量和年及季节降水模式。最大年降水量在海拔2000 m以下随海拔升高而增加，在海拔2000-3500 m范围内随海拔升高而减少。数据显示，只有在尼泊尔西部，年降水量与海拔高度呈负相关。在尼泊尔中部，0.25度网格上的年平均降水量超过3000毫米/年，但在尼泊尔西北部山区，年平均降水量不到1000毫米/年。只有尼泊尔西部的冬季降水量大于尼泊尔中部和东部的降水量。在尼泊尔平均的标准化降水异常时间序列没有显示出明显的长期趋势。此外，几乎没有站表现出显着的长期趋势，肯德尔的秩相关分析。夏季季风降水和全印度降雨（空气）指数之间的相关性分析显示，在尼泊尔西部和东部，分别为正相关和负相关。这项分析还发现，在尼泊尔西部和东部的夏季季风降水和南方涛动指数（SOI）之间的正相关，但没有负相关。温度，850百帕风，输出长波辐射（OLR），低和高空气阶段之间的降水率的复合差异显示，来自阿拉伯海的潮湿空气支持尼泊尔西部的降水，而来自青藏高原的干冷空气抑制尼泊尔东部的降水。然而，低和高SOI阶段之间的降水复合差异显示，尼泊尔没有异常。版权所有（C）2007皇家气象学会。
Rain gauge station data from 1987 to 1996 were used to investigate spatial and temporal variability in monthly precipitation and annual and seasonal precipitation patterns over Nepal. Maximum annual precipitation increased with altitude for elevations below 2000 m but decreased for elevations of 2000-3500 m. The data revealed a negative relationship between annual precipitation and elevation only in western Nepal. Annual precipitation averaged on a 0.25 degrees grid exceeded 3000 mm/yr in central Nepal but was less than 1000 mm/yr over Nepal's northwestern mountains. Only winter precipitation over western Nepal was heavier than precipitation over central and eastern Nepal. A time series of standardized precipitation anomalies averaged over Nepal revealed no significant long-term trends. Further, almost no stations exhibited significant long-term trends by Kendall's rank correlation analysis. A correlation analysis between summer monsoon precipitation and the All Indian Rainfall (AIR) index revealed positive and negative correlations in western and eastern Nepal, respectively. This analysis also revealed a positive correlation, but no negative correlation, between summer monsoon precipitation and the Southern Oscillation Index (SOI) in western and eastern Nepal. Composite differences in temperature, 850-hPa winds, outgoing longwave radiation (OLR), and precipitation rates between low and high AIR phases revealed that moist air from the Arabian Sea supported precipitation over western Nepal, whereas cold dry air from the Tibetan Plateau suppressed precipitation over eastern Nepal. However, composite differences in precipitation between low and high SOI phases revealed no anomalies for Nepal. Copyright (C) 2007 Royal Meteorological Society.