Atmospheric inertia-gravity waves retrieved from level-2 data of the satellite microwave limb sounder Aura/MLS

摘要

The temperature profiles of the satellite experiment Aura/MLS arehorizontally spaced by 1.5° or 165 km along the satellite orbit.These level-2 data contain valuable information about horizontal fluctuationsin temperature, which are mainly induced by inertia-gravity waves. Waveperiods of 2–12 h, horizontal wavelengths of 200–1500 km, and verticalwavelengths of 6–30 km efficiently contribute to the standard deviation ofthe horizontal temperature fluctuations. The study retrieves and discussesthe global distributions of inertia-gravity waves in the stratosphere andmesosphere during July 2015 and January 2016. We find many patterns that werepreviously present in data of TIMED/SABER, Aura/HIRDLS, and ECMWF analysis.However, it seems that Aura/MLS achieves a higher vertical resolution in thegravity wave maps since the maps are derived from the analysis of horizontalfluctuations along the orbit of the sounding volume. The zonal mean of theinertia-gravity wave distribution shows vertical modulations with scales of10–20 km. Enhanced wave amplitudes occur in regions of increased zonal windor in the vicinity of strong wind gradients. Further, we find a banana-likeshape of enhanced inertia-gravity waves above the Andes in the winter mesosphere.We find areas of enhanced inertia-gravity wave activity above tropical deepconvection zones at 100 hPa ( ∼ 13 km). Finally, we study the temporalevolution of inertia-gravity wave activity at 100 hPa in the Africanlongitude sector from December 2015 to February 2016.