Japan Geoscience Union Meeting 2015

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

[A-CG32] Multi-scale ocean-atmosphere interaction in the tropics

Tue. May 26, 2015 2:15 PM - 4:00 PM 202 (2F)

Convener:*Hiroki Tokinaga(Disaster Prevention Research Institute/Hakubi Center, Kyoto Univesity), Takuya Hasegawa(Japan Agency for Marine-Earth Science and Technology), Ayako Seiki(Japan Agency for Marine-Earth Science and Technology), Tomoki Tozuka(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Motoki Nagura(Japan Agency for Marine-Earth Science and Technology), Masamichi Ohba(Central Research Institute of Electric Power Industry (CRIEPI), Environmental Science Research Laboratory), Yukiko Imada(Atmosphere and Ocean Research Institute, the University of Tokyo), Chair:Hiroki Tokinaga(Disaster Prevention Research Institute/Hakubi Center, Kyoto Univesity), Masamichi Ohba(Central Research Institute of Electric Power Industry (CRIEPI), Environmental Science Research Laboratory)

2:55 PM - 3:10 PM

[ACG32-03] Turbulent mixing and its impact on lower tropospheric moisture over tropical ocean

*Hugo BELLENGER1, Masaki KATSUMATA1, Kunio YONEYAMA1 (1.Turbulent mixing and its impact on lower tropospheric 1 moisture over tropical ocean)

Keywords:turbulent mixing, lower-tropospheric moisture, CINDY/DYNAMO, tropical oceanic region

The variability of lower-tropospheric water vapor is a critical feature of the tropical climate. Among the processes that impact moisture budget, the vertical transport by turbulent mixing is generally overlooked. Using observations from CINDY/DYNAMO campaign, this is a first attempt to quantify it over the tropical ocean. Turbulent patches of size of O(100 m) are observed in relation with large vertical gradients of specific humidity. Intense mixing is diagnosed within these intermittent patches. Three approaches are used in order to diagnose the effect of this intermittent turbulence and reveal large uncertainties on the corresponding eddy diffusivity coefficient. The observed dry conditions are associated with steep moisture vertical gradients above the boundary layers. These steep gradients are potentially associated with moisture tendencies on the order of 0.5-1 g kg-1 day-1 that could play a role in the recovery phase following a dry intrusion or during the preconditioning stage of an MJO.