2000—2017年东印度洋季风带海域温度锋时空特征变化分析

基于2000-2017年的MODIS-Terra气候态月平均海表温度数据检测了东印度洋季风带海域的温度锋,统计了各锋面每月发生的锋点数量、锋面平均强度及中心线长度,并基于2000—2017年逐年海表温度数据,研究了以恒河-雅鲁藏布江河口锋和爪哇岛锋为代表的典型温度锋面的年际变化。结果发现:在3、4月,东印度洋季风带海域的锋面最弱、数量最少;5-10月期间,5°~15°N及5°~15°S一带的温度锋出现并发展;12、1、2月最北部锋面发展并趋向成熟。研究区存在恒河-雅鲁藏布江河口锋、爪哇岛锋、Palk海峡锋、东锡兰锋及伊洛瓦底江河口锋5个温度锋,其中最北部的恒河-雅鲁藏布江河口锋全年存在,东北季风时期长度较长,强度较大,最南部的爪哇岛锋存在于4—11月,西南季风时期较强,长度和数量也处于较高水平,其余锋面主要发生于西南季风盛行时期,且强度、长度等变化相对较小。两个典型温度锋空间位置的年际变化均不大,恒河-雅鲁藏布江河口锋平均强度的年际变化较大,最大超过0.03℃/km,长度变化相对较小;爪哇岛锋平均强度的变化相对平稳,但锋点数量和中心线长度存在较大的年际变化。

Analysis of temporal and spatial characteristics of temperature front in the East Indian Ocean monsoon zone from 2000 to 2017

Based on the monthly average sea surface temperature(SST)data of MODIS-Terra climatology from 2000 to 2017,this paper tested the temperature front in the East Indian Ocean monsoon zone,and calculated the number of fronts,the average intensity and the centerline length of each front statistically.Based on the annual SST data from 2000 to 2017,the annual variation of the typical temperature front represented by the Ganges-Brahmaputra Estuarine front and the Java Island front was studied.It was found that in March and April,the front of the East Indian Ocean monsoon zone was the weakest with the least number;during the period of May to October,the temperature fronts of 5°-15°N and 5°-15°S appeared and developed.In December,January and February,the northern front developed and matured.There were five temperature fronts in the study area:the Ganges-Brahmaputra Estuarine front,the Java Island front,the Palk Strait front,the East Ceylon front and the Irravadi Estuarine front.The northernmost Ganges-Brahmaputra Estuarine front was present throughout the year,and the length of the northeast monsoon period was longer and stronger;the Java Island front existed from April to November,the southwest monsoon period was stronger,the length and the number of front points were also at a high level;the other fronts mainly occured during the prevailing period of the southwest monsoon,and the changes in intensity and length were relatively small.The annual variation of the spatial position of the two typical temperature fronts was small,and the annual variation of the average intensity of the Ganges-Brahmaputra Estuarine front was greater than 0.03℃/km,and the change in length was relatively small.The change of the average intensity of the Java Island front was relatively stable,while there were significant variations in the number of front points and the length of the centerline.