Interdecadal Shifts in the Winter Monsoon Rainfall of the Philippines
Interdecadal Shifts in the Winter Monsoon Rainfall of the Philippines
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DOI：
10.3390/atmos9120464
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发表时间：
2018-11
期刊：
影响因子：
2.9
通讯作者：
L. Olaguera;J. Matsumoto;H. Kubota;Tomoshige Inoue;E. Cayanan;F. Hilario
中科院分区：
文献类型：
--
作者：
L. Olaguera;J. Matsumoto;H. Kubota;Tomoshige Inoue;E. Cayanan;F. Hilario
本研究调查了1961年至2008年菲律宾冬季风（11月至次年3月）降水的年代际变化。对冬季风降水的逐月分析表明，这种变化在12月最为显著。特别是，1976/1977年和1992/1993年左右的12月降雨时间序列中确定了两个年代际变化。为了便于研究导致这些变化的可能机制，分析期分为三个时期：1961-1976（E1），1977-1992（E2）和1993-2008（E3）。与相邻两个时期相比，E2期间降水的平均和年际变率被抑制。1976/1977年前后的变化与太平洋年代际涛动（PDO）由负位相向正位相的转变有关，表现为太平洋海盆海温（SST）的类厄尔尼诺变化; 1992/1993年前后的变化与太平洋海盆SST的类拉尼娜变化有关。对大尺度环流特征的进一步分析表明，低层东风减弱、水汽输送减少和热带气旋活动减少是E2期间平均降水减少的主要原因。此外，E2期间降水年际变率的抑制可以部分归因于类厄尔尼诺的海温变化和东亚冬季风的减弱。
This study investigates the interdecadal shifts in the winter monsoon (November to March) rainfall of the Philippines from 1961 to 2008. Monthly analysis of the winter monsoon rainfall shows that the shifts are most remarkable during December. In particular, two interdecadal shifts are identified in the December rainfall time series around 1976/1977 and 1992/1993. To facilitate the examination of the possible mechanisms leading to these shifts, the analysis period is divided into three epochs: 1961–1976 (E1), 1977–1992 (E2), and 1993–2008 (E3). The mean and interannual variability of rainfall during E2 are suppressed compared with the two adjoining epochs. The shift around 1976/1977 is related to the phase shift of the Pacific Decadal Oscillation (PDO) from a negative phase to a positive phase and features an El Niño-like sea surface temperature (SST) change over the Pacific basin, while that around 1992/1993 is related to a La Niña-like SST change. Further analysis of the largescale circulation features shows that the decrease in the mean rainfall during E2 can be attributed to the weakening of the low-level easterly winds, decrease in moisture transport, and decrease in tropical cyclone activity. In addition, the suppressed interannual variability of rainfall during E2 can be partly attributed to the El Niño-like SST change and the weakening of the East Asian winter monsoon.