Recent rainfall conditions in the Congo Basin
Recent rainfall conditions in the Congo Basin
复制标题
DOI：
10.1088/1748-9326/ac61c4
复制
发表时间：
2022-03
影响因子：
6.7
通讯作者：
S. Nicholson;D. Klotter;Liming Zhou;W. Hua
中科院分区：
文献类型：
--
作者：
S. Nicholson;D. Klotter;Liming Zhou;W. Hua
在刚果盆地，1979年至2014年期间，4月至5月至6月的降雨普遍存在干旱趋势，同时森林生产力下降。本文研究了随后的几年，以确定降雨条件是否有所改善，并研究这些年的气象因素。结果表明，与1979 - 1993年相比，2016 - 2020年是一个更潮湿的时期。然而，造成较潮湿情况的气象因素似乎与较早潮湿时期的气象因素有很大不同。与2000 - 2014年的干燥阶段相比，1979 - 1993年的潮湿条件与热带步行者环流，水分通量和通量散度以及太平洋海面温度（SST）的变化有关，即中部和东部太平洋变暖，西太平洋变冷。这导致跨太平洋海温梯度低于平均水平。相比之下，2016 - 2020年期间的SST几乎普遍高于前两个时期。然而，跨太平洋梯度有所下降。步行者环流和水汽通量/通量辐散不是影响这次事件的主要因素。促使回归多雨年份的主要因素似乎是对流可用位能和总柱水蒸气的增加。这可能与海洋和陆地的普遍变暖有关。
In the Congo Basin, a drying trend in the April–May–June rains prevailed between 1979 and 2014, accompanied by a decline in forest productivity. This article examines the subsequent years, in order to determine whether rainfall conditions have improved and to examine meteorological factors governing conditions in those years. It is shown that a wetter period, comparable to that of 1979–1993, spanned the years 2016–2020. However, the meteorological factors responsible for the wetter conditions appear to be significantly different from those related to the earlier wet period. The wetter conditions of 1979–1993 were associated with changes in the tropical Walker circulation, in moisture flux and flux divergence, and in Pacific sea-surface temperatures (SST), namely a warmer central and eastern Pacific and a cooler western Pacific, compared to the dry phase in 2000–2014. This resulted in a lower-than-average trans-Pacific SST gradient. In contrast, SSTs were almost ubiquitously higher in the 2016–2020 period than in either prior period. However, there was some reduction in the trans-Pacific gradient. The Walker circulation and moisture flux/flux divergence were not factors in this episode. The major factors provoking the return to wetter years appear to be an increase in convective available potential energy and in total column water vapor. This could be related to the general warming of the oceans and land.