Characteristics of gravity waves with short vertical wavelengths observed with radiosonde and GPS occultation during DAWEX (Darwin Area Wave Experiment)

Abstract

We conducted radiosonde soundings during three intensive observation periods (IOP) of the Darwin Area Wave Experiment (DAWEX) campaign in October to December 2001 and measured humidity, temperature, and wind velocity up to ∼30–35 km every 3 hours for 40 times at three sites in each IOP. We analyzed height profiles of kinetic (Ek) and potential (Ep) energy per unit mass caused by gravity waves with vertical wavelengths less than 3 km. The wave energy was clearly enhanced between 15–20 km and 25–30 km, and it was considerably depressed at 20–25 km between the two height regions. This feature was seen at all the sites during the three IOPs. Different types of wave activity seem to contribute to the enhancement of Ek and Ep below 20 km and at 25–30 km. Height distribution of the wave energy at 20–30 km seems to correlate with the structure of the mean zonal wind shear. We also analyzed a latitude‐height section of Ep in October to December 2001 using GPS occultation data with the CHAMP satellite collected around the DAWEX sites (80–180°E and 30°N to 30°S). Compared with the latitude distribution of Ep with GPS, the DAWEX results were slightly smaller and larger at 20–25 km and 25–30 km, respectively. The longitude variation of Ep is also analyzed from the GPS data at 10–15°S, which generally agreed well with the DAWEX results at both 20–25 km and 25–30 km.