Influence of the El Niño Southern Oscillation on the middle and upper atmosphere

摘要: [1] Based on Whole Atmosphere Community Climate Model (WACCM) simulations, Pedatella and Liu (2012) recently demonstrated that significant interannual variability occurs in migrating nonmigrating tides the mesosphere lower thermosphere (MLT) due to El Nino Southern Oscillation (ENSO). The role of changes tropospheric forcing, zonal mean atmosphere, planetary wave-tide interactions generating tidal MLT are investigated present study. ENSO-driven diurnal tide (DW1) is found be primarily forcing DW1. Changes also source eastward propagating with wave number 3 (DE3). However, atmosphere contribute DE3 ENSO. Variability 2 (DE2) largely background a smaller additional contribution forcing. westward semidiurnal 4 (SW4) believed waves during ENSO which will enhance generation SW4 through nonlinear interaction stationary 2. influence longitude structure low-latitude ionosphere Comparison La Nina time periods reveals introduces ~2–4 ms−1 daytime vertical drift velocity at certain longitudes. Simulation results further illustrate drives F region maximum electron density (NmF2). demonstrate ~10–30% ~10–15% ionosphere. should therefore considered as potentially Earth's upper atmosphere.