资源环境科技发展态势分析平台

The seasonal and height dependencies of the orographic primary and larger-scale secondary gravity waves (GWs) have been studied using the temperature profiles measured by Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) from 2002 to 2017. At similar to 40 degrees S and during Southern Hemisphere winter, there is a strong GW peak over the Andes mountains that extend to z similar to 55 km. Using wind and topographic data, we show that orographic GWs break above the peak height of the stratospheric jet. At z similar to 55-65 km, GW breaking and momentum deposition create body forces that generate larger-scale secondary GWs; we show that these latter GWs form a wide peak above 65 km with a westward tilt. At middle latitudes during summer in the respective hemisphere, orographic GW breaking also generates larger-scale secondary GWs that propagate to higher altitudes. Both orographic primary and larger-scale secondary GWs are likely responsible for most of the non-equatorial peaks of the persistent global distribution of GWs in SABER.

Plain Language It is important to characterize orographic primary gravity waves (GWs) and the larger-scale secondary GWs via both observations and numerical modeling because of their role in dynamics of the atmosphere. We present the global distributions of GWs and the associated larger-scale secondary GWs in the middle atmosphere (z similar to 30-100 km) from temperature profiles measured by the SABER instrument over the past 16 years (2002-2017). We show that the peaks of the primary and the associated secondary GWs coincide with topographic peaks and that these associations depend on latitude and season. The polar stratospheric jet and the lower stratospheric wind reversal cause the orographic GWs break. The breaking GWs deposit their momentum and induce body forces that generate larger-scale secondary GWs; these secondary GWs are responsible for the GWs peaks observed above the mountain wave breaking height.