Can Climate Models Simulate the Observed Strong Summer Surface Cooling in the Equatorial Atlantic?.

Dippe, Tina, Krebs, Martin, Harlaß, Jan and Lübbecke, Joke F. (2018) Can Climate Models Simulate the Observed Strong Summer Surface Cooling in the Equatorial Atlantic?. Open Access In: YOUMARES 8 – Oceans Across Boundaries: Learning from each other. . Springer, Cham, Switzerland, pp. 7-23. ISBN 978-3-319-93284-2 DOI 10.1007/978-3-319-93284-2_2.

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Abstract

Variability in the tropical Atlantic Ocean is dominated by the seasonal cycle. A defining feature is the migration of the inter-tropical convergence zone into the northern hemisphere and the formation of a so-called cold tongue in sea surface temperatures (SSTs) in late boreal spring. Between April and August, cooling leads to a drop in SSTs of approximately 5°. The pronounced seasonal cycle in the equatorial Atlantic affects surrounding continents, and even minor deviations from it can have striking consequences for local agricultures.

Here, we report how state-of-the-art coupled global climate models (CGCMs) still struggle to simulate the observed seasonal cycle in the equatorial Atlantic, focusing on the formation of the cold tongue. We review the basic processes that establish the observed seasonal cycle in the tropical Atlantic, highlight common biases and their potential origins, and discuss how they relate to the dynamics of the real world. We also briefly discuss the implications of the equatorial Atlantic warm bias for CGCM-based reliable, socio-economically relevant seasonal predictions in the region.

Document Type: Book chapter
Additional Information: This article is related to the YOUMARES 8 conference session no. 3: “Physical Processes in the Tropical and Subtropical Oceans: Variability, Impacts, and Connections to Other Components of the Climate System”. The original Call for Abstracts and the abstracts of the presentations within this session can be found in the appendix “Conference Sessions and Abstracts”, chapter “1 Physical Processes in the Tropical and Subtropical Oceans: Variability, Impacts, and Connections to Other Components of the Climate System”, of this book.
Keywords: Tropical Atlantic; Seasonal cycle; Climate variability; Coupled global climate models; Climate model bias
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-TM Theory and Modeling
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Refereed: Yes
Publisher: Springer
Date Deposited: 11 Sep 2018 07:46
Last Modified: 11 Sep 2018 07:46
URI: https://oceanrep.geomar.de/id/eprint/44188

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