The Influence of Gravity Waves on Ice Saturation in the Tropical Tropopause Layer over Darwin, Australia
| Autor: | Andrew M. Dzambo, Matthew H. Hitchman, Kai-Wei Chang |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Cloud fraction Perturbation (astronomy) gravity waves tropical tropopause clouds radiosondes Environmental Science (miscellaneous) 010502 geochemistry & geophysics Monsoon Atmospheric sciences 01 natural sciences law.invention Troposphere ice saturation law water vapor Radiosonde Environmental science Negative temperature Stratosphere Water vapor 0105 earth and related environmental sciences |
| Zdroj: | Atmosphere Volume 10 Issue 12 |
| ISSN: | 2073-4433 |
| DOI: | 10.3390/atmos10120778 |
| Popis: | Gravity waves (GWs) in the tropical tropopause layer (TTL) can help dehydrate the lower stratosphere through rapid cooling events, but observational studies of GWs in the TTL are limited. Using a long-term, high-resolution radiosonde temperature dataset, an atmospheric state classification technique, and wavelet analysis, we characterize temperature perturbations generated by GWs in the TTL over Darwin, Australia across eight atmospheric states. We find a peak in GW power just above the tropical tropopause and a climatological maximum during peak monsoon season. While accounting for a chronic negative temperature bias near the tropical tropopause, we estimate that, in the upper troposphere, GWs impose a 2 K temperature perturbation during non-monsoon states and a 3 K temperature perturbation during the monsoon states, with corresponding values of 5 K and 6 K in the upper TTL. A 3 K negative temperature perturbation will lead to significant perturbations in relative humidity with respect to ice, which has implications for environmental ice number concentrations and TTL cloud fraction. |
| Databáze: | OpenAIRE |
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