Interannual variability of rainfall characteristics over southwestern Madagascar
Interannual variability of rainfall characteristics over southwestern Madagascar
复制标题
马达加斯加西南部降雨特征的年际变化
DOI：
10.1007/s00704-015-1719-0
复制
发表时间：
2017
影响因子：
3.4
通讯作者：
C. Reason
中科院分区：
文献类型：
--
作者：
T. Randriamahefasoa;C. Reason
研究了马达加斯加西南部地区的日降雨频率[> ~ 1mm /d]和强降雨[> ~ 30mm /d]的年际变化，该地区相对于该岛其他地区相对干旱。重点关注从12月到3月的夏季雨季，在四个站点（Morondava、Ranohira、Toliara和Taolagnaro），这些站点1970-2000年的日降雨量数据来自马达加斯加气象局。发现El Niño南方涛动（ENSO）与每个站点的湿润日频率有相对较强的相关性，特别是在极西南的Toliara。就季节降雨总量而言，大多数El Niño （La Niña）夏季的降雨量低于（高于）平均水平。ENSO与强降雨事件之间的联系尚不清楚。然而，对于强降雨事件，相关的大气环流在整个半球表现出类似南环模的模式。ENSO年和1979/80年、1981/82年的中性季节湿润日频率异常较大，区域大气环流模式由马达加斯加西南部及其附近低层水汽辐合和抬升的强烈异常组成，相应地使条件或多或少有利于降雨。马达加斯加南部的干（湿）夏季也与该地区的东太平洋环流区向赤道（极）方向移动有关。
The interannual variability of daily frequency of rainfall [>1 mm/day] and heavy rainfall [>30 mm/day] is studied for the southwestern region of Madagascar, which is relatively arid compared to the rest of the island. Attention is focused on the summer rainy season from December to March at four stations (Morondava, Ranohira, Toliara and Taolagnaro), whose daily rainfall data covering the period 1970–2000 were obtained from the Madagascar Meteorological Service. El Niño Southern Oscillation (ENSO) was found to have a relatively strong correlation with wet day frequency at each station and, particularly, for Toliara in the extreme southwest. In terms of seasonal rainfall totals, most El Niño (La Niña) summers receive below (above) average amounts. An ENSO connection with heavy rainfall events was less clear. However, for heavy rainfall events, the associated atmospheric circulation displays a Southern Annular Mode-like pattern throughout the hemisphere. For ENSO years and the neutral seasons 1979/80, 1981/82 which had large anomalies in wet day frequency, regional atmospheric circulation patterns consisted of strong anomalies in low-level moisture convergence and uplift over and near southwestern Madagascar that made conditions correspondingly more or less favourable for rainfall. Dry (wet) summers in southern Madagascar were also associated with an equatorward (poleward) displacement of the ITCZ in the region.