Understanding Pacific Ocean influence on interannual precipitation variability in the Sahel. Issue 17 (9th September 2016)

• Record Type: Journal Article
• Authors: Pomposi, Catherine; Giannini, Alessandra; Kushnir, Yochanan; Lee, Dong Eun
• Is Part Of: Geophysical research letters. Volume 43:Issue 17(2016)
• Page Start: 9234
• Page End: 9242
• Publication Date: 2016-09-09
• Subjects: monsoon -- Sahel -- moisture budget -- El Nino; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL069980
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Moisture budget decomposition is performed for the Sahel (10°–20°N and 20°W–40°E) in order to understand the processes that govern regional hydroclimate variability on interannual time scales and frame them in the context of their primary ocean driver. Results show that warm conditions in the Eastern Tropical Pacific remotely force anomalously dry conditions primarily through affecting the low‐troposphere mass divergence field. This behavior is related to increased subsidence over the tropical Atlantic and into the Sahel and an anomalous westward flow of moisture from the continent, both resulting in a coherent drying pattern. Understanding the physical processes relating remote sea surface temperature anomalies to atmospheric circulation changes and the resulting complex local convergence patterns is important for advancing seasonal prediction of precipitation over West Africa. Key Points: Net surface moisture is reduced during El Niño primarily by anomalous atmospheric mass divergence Anomalous mass divergence follows a Gill‐Matsuno response to a heating anomaly in the Pacific Results support prior hypotheses of remote basins control on Sahel precipitation variability