The Relationship between Stratospheric Gravity Wave Potential Energy and Tropospheric Parameters over South America inferred from COSMIC-2 and METOP Radio Occultation Measurements

Abstract

AbstractUsing COSMIC-2 and METOP radio occultation measurements during the years 2020 and 2021, the study presents the first direct and independent relationship between the potential energy (Ep) in the stratosphere, precipitable water vapour (PWV), tropopause heights, and cold-point heights over South America. The South American continent comprises the tropical region, the Andes Mountain range, and the mid-latitude climates. The seasonal mean of the potential energy (Ep), the PWV, and the tropopause parameters height (TPH and CPH) were obtained to investigate the relationship between the SGW Epand the tropospheric parameters (PWV, TPH, and CPH). Around the Andes Mountains to the east, there is significantly less water vapour (PWV < 10 mm) and relatively high gravity wave Ep(Ep>8 kJ kg− 1). A good correlation of variability was found between the PWV and the lower stratospheric gravity wave (SGW) Epin summer over the tropical region (± 20◦). Our result affirmed the possibility that convective activity was a major driver of the tropical gravity waves over South America. In the subtropical (30◦-40◦) region, especially in the winter, the tropospheric parameters make little or no contribution to gravity wave activity in the region. The tropopause and the cold-point temperature showed an anti-correlation (r > − 0.6) with SGW over the South American tropics. The SGW activities in the tropical region showed an impact on the structure of the tropopause parameters, which could be a result of the convective activity in this region.