Title

Contrasting Cloud Radiative Feedbacks during Warm Pool and Cold Tongue El Ninos

Document Type

Article

Publication Date

1-1-2018

Publication Title

SOLA : Scientific Online Letters on the Atmosphere

ISSN

1349-6476

Volume

14

DOI

10.2151/sola.2018-022

Abstract

The study presents the contrasting characteristics of cloud-radiative feedbacks to the cold tongue (CT) and warm pool (WP) El Niño (EN). The maximum sea surface temperature anomalies (SSTA) of the CT-EN are located in the far-eastern Pacific. However, the maximum responses of the shortwave- and longwave- cloud-radiative forcing (SWCRF and LWCRF) to the CT-EN warming are centered near the dateline, showing 70° westward shift relative to the maximum SSTA center of CT-WN. In contrast, the maximum responses of the SWCRF and LWCRF to the WP-EN warming show only slight westward shift relative to the maximum SSTA center. The contrasting cloud-radiative feedbacks to the two types of ENs can be traced back to the contrasting precipitation feedbacks, which is associated with the convection threshold. When the warm SSTA of CT-EN occurs in the relatively cold eastern Pacific, the total SST in-situ may not exceed the convection threshold. Therefore, the induced precipitation anomaly would occur towards the warm western Pacific, and the corresponding cloud cover and cloud-radiative feedbacks would exhibit an apparent westward shift. As the warm SSTA of WP-EN occurs in the relatively warm central Pacific, the corresponding responses of the anomalous fields to the WP-EN show only slight westward displacement.

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