Joint Seminar: Changes in ENSO-driven precipitation anomalies under global warming

Eastward shift and extension of ENSO-induced tropical precipitation anomalies under global warming . During El Niño events, increased precipitation is observed over the equatorial central-eastern Pacific, corresponding to enhanced moist convective heating there, which modulates global climate through exciting atmospheric teleconnections. The precipitation anomalies are projected to shift and extend eastward in response to global warming. Here, we show that the change is caused by the projected narrowing of the meridional span of the underlying El Niño-related sea surface temperature (SST) anomalies. This narrowing leads to the intensification of the meridional gradient of the SST anomalies, strengthening boundary-layer moisture convergence over the equatorial eastern Pacific and enhancing local positive precipitation anomalies. The resultant eastward shift and extension of these anomalies also causes the intensification and eastward extension of negative precipitation anomalies, typically seen over the tropical western north Pacific (WNP) during El Niño, through strengthening equator-ward advection of mean low moist enthalpy by enhanced anomalous wind. The change in the El Niño-induced tropical precipitation anomalies implies that El Niño events tend to decay faster after their peak phase under global warming, shortening El Niño events.

Date

07.08.2019

Time

13:30 h

Place

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Speaker

Bo Wu, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences

Chair

Chao Li

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