Читать книгу Congo Basin Hydrology, Climate, and Biogeochemistry - Группа авторов - Страница 27

The prominence of central Africa in the tropical climate system is well established. Central Africa is one of the three major global hotspots of convective activity, which are a key part of the large‐scale air circulation that transfers warm air from the tropics toward the poles, thereby contributing to the regulation of global climate. The regional climate system is associated with the world’s greatest frequency of thunderstorms and lightning (Cecil et al., 2015; Clulow et al., 2018). Central Africa has an extensive wetland and the regional hydrography is dominated by the Congo Basin, which is the biggest water catchment in Africa, holding 30% of the continent’s water resources (Brummett et al., 2008), and the second‐largest catchment in the world. The Congo Basin, with over thousands of kilometers of navigable waterways, presents an opportunity to adapt and reduce the effect of climate change on the Lake Chad Basin through the possibility of interbasin water transfer (Salman & Momha, 2009). The wealth of biodiversity over central Africa is abundant. It has the second‐largest tropical forest on Earth, with evergreen trees and thousands of species of plants, and hundreds of species of mammals and birds. Carbon sequestration by the Congo forest contributes to climate regulation and thereby mitigates climate change (Eba’a et al., 2015).

It follows that gaps in the understanding of the climate of central Africa, and how it may change in the future, are substantial limitations. Such gaps hinder the confidence in the risk to which biodiversity is exposed and, in turn, the Earth’s future. Over the African continent, central Africa is the region where climate models generally suffer from poor performance. The direction of the future climate of central Africa is uncertain as there is strong disagreement between climate model projections (Dosio et al., 2019). These deficiencies are because the models fail to represent observed climate well, and the contemporary climate system is poorly observed (Washington et al., 2013). Deficiency in the investigation of the central African climate leads to development of theories on its functioning built on concepts imported from other regions that are sometimes not suitable to the regional dynamics (Nicholson, 2018). These conjectures likely induce misleading information in the current understanding on the regional climate, and suggest the investigation of gaps. To this effect, our goal is to explore key gaps in the understanding of the climate of central Africa, while presenting the advances made recently.

This study reviews recent advances in drivers of the climate regime over central Africa and highlights aspects that merit further attention. The focus is on annual rainfall regime and associated mechanisms. Current knowledge in regional atmospheric dynamic and associated potential for understanding rainfall regime is presented. This paper is organized as follows: Section 2.2 presents mechanisms linked to the annual rainfall regime and related insufficiency. Section 2.3 deals with convection and associated gaps. The consequence of the knowledge gap in the functioning of regional climate on climate modeling is presented in Section 2.4, and conclusions are presented in Section 2.5.