Diurnal Variations in Middle Atmospheric Water Vapor
Abstract
We will present results of a study of diurnal variations in water vapor using ground-based microwave measurements from the Water Vapor Mm-wave Spectrometer (WVMS) instruments from the Network for Detection of Atmospheric Composition Change (NDACC) sites at Mauna Loa, Hawaii, and Table Mountain, California. Because the diurnal signal is small, the diurnal variations are calculated using several years of hourly binned measurements. While there is a well understood photochemical diurnal water vapor in the upper mesosphere, we will focus here on variations in the upper stratosphere/lower mesosphere, where variations have been reported and been attributed to advection. In addition to the WVMS measurements, we will make use of hourly-binned diurnal variations in temperature provided by the Naval Global Environmental Model-High Altitude (NAVGEM-HA) analyses. These temperature variations, which are in large part driven by ozone heating, will drive advection near the stratopause, and will therefore drive diurnal variations in water vapor. However, these diurnal temperature variations must also be considered as part of the ground-based microwave water vapor retrieval process. We find that, near the stratopause, the effect of this diurnal temperature variation on the water vapor retrievals near the stratopause are of comparable magnitude to the measured water vapor variations themselves. Finally, we will compare the WVMS water vapor retrievals with hourly-binned water vapor diurnal variations from the NAVGEM-HA analyses.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A41I3088N
- Keywords:
-
- 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0341 Middle atmosphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3334 Middle atmosphere dynamics;
- ATMOSPHERIC PROCESSES