JpGU-AGU Joint Meeting 2020

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-CG Complex & General

[A-CG45] Multi-scale ocean-atmosphere interaction in the tropical Indo-Pacific region

convener:Yu Kosaka(Research Center for Advanced Science and Technology, University of Tokyo), Sang-Wook Yeh(Hanyang University), Takanori Horii(Research and Development Center for Global Change (RCGC), Strategic Research and Development Area, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)), Hiroki Tokinaga(Disaster Prevention Research Institute, Kyoto University)

[ACG45-01] Impacts of Arabian Sea SST biases on Indian monsoon precipitation and eastern Mediterranean climate in a coupled GCM

★Invited Papers

*Yoko Yamagami1, Hiroaki Tatebe2, Masahiro Watanabe1 (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Japan Agency for Marine-Earth Science and Technology)

Keywords:Arabian Sea, Monsoon-desert mechanism, Mesoscale eddy, Climate model

We investigated impacts of sea surface temperature (SST) biases in the Arabian Sea on Indian summer monsoon precipitation and eastern Mediterranean climate, using a climate model called MIROC6 with two configurations (standard and eddy-permitting ocean model referred to as “Subhires”).
In the Subhires model, resolving the warm water outflow from marginal seas and heat transport by mesoscale eddies reduce mean cold SST biases over the Arabian Sea. Higher SST in the Arabian Sea results in cyclonic atmospheric circulation over the northern Arabian Sea, which increases precipitation in northwestern India during summer. Atmospheric general circulation model (AGCM) sensitivity experiments show that SST differences only in the northern Arabian Sea can lead to atmospheric circulation anomalies and precipitation increase in northwestern India.
It is also found that the Subhires model simulates a teleconnection from the monsoon rainfall better than the standard model. The teleconnection occurs at an interannual time scale between the Indian summer monsoon rainfall variability and descent over the eastern Mediterranean Sea, resulting from a monsoon-desert mechanism. AGCM sensitivity experiments show that higher SST in the northern Arabian Sea enhances descent anomalies in the eastern Mediterranean region, responding to precipitation increase in northwestern India.