Seasonal variation of the diurnal cycle of rainfall in the eastern equatorial Indian Ocean
Seasonal variation of the diurnal cycle of rainfall in the eastern equatorial Indian Ocean
复制标题
赤道东印度洋降水日周期的季节变化
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Unnikrishnan
中科院分区：
文献类型：
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作者：
M. R. Ramesh Kumar;S. M. Pednekar;M. Katsumata;M. K. Antony;Y. Kuroda;A. Unnikrishnan
利用位于1.5° S和90° E的Triton浮标的逐时资料，研究了2001年10月23日至2003年10月31日期间赤道东印度洋降水的日变化。对不同季节降雨活跃和减弱的分析显示，2002年冬季、夏季和秋季的傍晚和清晨（春季）的降雨量最高。2003年冬、春、夏三季降水活跃期的峰值出现在下午，这与Janowiak等人（1994）的研究结果一致。对降雨事件的分析表明，2002年秋季的降雨事件数量最多（90次），2003年春季的降雨事件数量最少（60次）。此外，还发现在整个研究期间，大多数降雨事件（>60%）的持续时间小于3小时。持续时间较长的降雨事件（即持续时间超过6小时的降雨事件）对2002年春季（占总降雨量的20%）和2003年冬季（占总降雨量的21%）的贡献显着。不同季节的小时降雨量数据的谐波分析表明，日谐波解释所有季节的方差超过80%。此外，周日谐波有一个最大的振幅，除夏季，其中半日和六小时谐波是显着的所有季节。
SummaryThe diurnal cycle of rainfall over the eastern equatorial Indian Ocean was studied for the period 23rd October 2001 to 31st October 2003 using hourly data from the Triton buoy positioned at 1.5° S and 90° E. An analysis of the active and weak spells of rainfall for different seasons revealed peaks in the late evening hours in Winter, Summer and Fall and in early morning hours (in Spring) in 2002. The active spell of rainfall peaked in the afternoon hours, during Winter, Spring and Summer in 2003, which agrees with the previous results of Janowiak et al. (1994). An analysis of rainfall events showed that Fall 2002 had a maximum number of rainfall events (90) and minimum (60) were observed in Spring 2003. Further it was found that the majority of rain events (>60%) were less than 3 hours in duration throughout the study period. The longer duration rainfall events (i.e. rain events greater than 6 hour duration) contributed significantly to Spring 2002 (20% of the total rainfall) and Winter 2003 (21% of the total rainfall). Harmonic analysis of the hourly rainfall data for different seasons revealed that diurnal harmonic explains more than 80% of the variance for all seasons. Furthermore, the diurnal harmonic has a maximum amplitude for all seasons except summer, where the semidiurnal and six hourly harmonics are significant.