JpGU-AGU Joint Meeting 2020

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS08] Stratosphere-troposphere interaction

convener:Takatoshi Sakazaki(Graduate School of Science, Kyoto University), Takenari Kinoshita(Japan Agency for Marine-Earth Science and Technology), Pu Lin(Princeton University/NOAA Geophysical Fluid Dynamics Laboratory), Peter Hitchcock(Cornell University)

[AAS08-10] Do sudden stratospheric warmings boost convective activity in the tropics?

*Kohei Yoshida1 (1.Meteorological Research Institute)

Keywords:Stratosphere-Troposphere coupling in the tropics, Sudden Stratospheric Warming, Tropical convection, Tropical cyclone, Large ensemble simulation

Influence of stratospheric circulation changes related to sudden stratospheric warmings (SSW) on the tropical troposphere have been examined in many previous studies. However, due to small sample size of SSW and large internal variability in the tropical troposphere, influence of the SSW on the tropical troposphere is still uncertain. We examine impact of the stratospheric circulation changes related to SSW on the tropical troposphere using 5,000-year scale ensemble simulations with a 60 km horizontal resolution global atmospheric model MRI-AGCM3.2. Thousands of SSW-like circulation change events are extracted thanks to the large ensemble simulations. A composite analysis of the SSW-like events shows significant stratospheric upwelling and cooling in the tropics. Synchronized with the upwelling, statistically robust tropospheric signals such as raised temperature and enhanced convective activity including tropical cyclone are found. Although the mean tropospheric signals tend to be small in the view of S/N ratio (~0.1), relative probability of their extreme events significantly increases.