JpGU-AGU Joint Meeting 2020

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P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

convener:Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Yuichi Otsuka(Institute for Space-Earth Environmental Research, Nagoya University), Yue Deng(University of Texas at Arlington), Loren Chang(Institute of Space Science, National Central University)

[PEM12-P10] Spatial and temporal distributions of atmospheric gravity wave potential energy evaluated using ERA-5 temperature data over the equatorial latitudes

*Shih-Sian Yang1, Chen-Jeih Pan1, Uma Das2, Chian-Chiau Lin3 (1.National Central University, Jhongli, Taoyuan 32001, Taiwan, 2.Department of Physics, Indian Institute of Information Technology, India, 3.Environmental Research and Information Center, Chang Jung Christian University, Taiwan)

Keywords:Atmospheric gravity waves, Potential energy, Zonal wind, Wave-mean flow interactions, ERA-5

In this study, we used the temperature profiles retrieved from ERA5, the newest atmospheric reanalysis dataset issued by the European Centre for Medium-Range Weather Forecasts (ECMWF), to evaluate the potential energy (EP) in the atmosphere from the near ground surface to ~80 km altitude over the equatorial latitudes of ±10°. EP is calculated from the fluctuation of temperature, which is considered to be generated by atmospheric gravity waves (AGWs), and we have constructed the spatial and temporal distributions of EP over the equatorial latitudes using the high-resolution data from ERA5. In this study, we will present the variations of EP in time, altitude, and longitude. Overall, EP is controlled by the zonal flow of the background atmosphere. Especially the time-varied descending structures of high EP value coincide with the westerly shear of zero-wind in the stratosphere, which implies the Kelvin wave-mean flow interactions in the stratospheric altitudes. Besides, the longitudinal analysis shows that EP is higher in the eastern Pacific at all altitudes except around the tropopause. In addition, we checked the EP values during different atmospheric and oceanic conditions, to examine the possible relationship between El Niño/La Niña and atmospheric gravity waves. With regards to the EP distribution caused by Kelvin waves in the stratosphere, we will also compare the results with the Kelvin wave amplitudes obtained by the two-dimensional fast Fourier transform (2D-FFT) method in this presentation.