Detecting Mid-Tropospheric Clouds Using COSMIC-2 Radio Occultations, GFS Forecasts, and GOES-16 ABI Measurements
Abstract
The second-generation Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC-2) mission was launched in June 2019, and radio occultation (RO) measurements are available from the fall of 2019 to the present. The primary scientific goal of COSMIC is to demonstrate the value of near-real-time RO observations to operational numerical weather prediction (NWP). A primary goal of our study is to investigate the information content of RO observations relative to cloud presence along the RO atmospheric path. RO observations of profiles of microwave refractivity are first order insensitive to cloud presence. However, from the mid-troposphere upward, the extraordinary vertical resolution of RO refractivity and "dry temperature" profiles motivate the inferences of cloud presence and height based on the vertical thermodynamic structure of the atmosphere. Preliminary investigations are revealing signatures in profiles of the difference between RO dry temperature and GFS forecast temperature, that strongly suggest cloud presence. When coupled with GFS forecast relative humidity, this temperature difference correctly indicates the cloud state (i.e., as cloudy or cloud-free) approximately 82% of the time based on a training ensemble of over 3000 COSMIC-2 profiles. In this preliminary portion of our study we are using NWP cloud water fields as cloud truth. In the next phase, a more robust cloud truth analysis will be attained through the use of coincident GFS and GOES-16 ABI observations to replace the GFS analysis cloud water forecasts by themselves, with the hope for achieving similar cloud detection accuracies. Should this research succeed, the result will be a valuable detector of cirrus and other mid-tropospheric clouds at night.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA211.0015M
- Keywords:
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- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES;
- 3359 Radiative processes;
- ATMOSPHERIC PROCESSES;
- 3360 Remote sensing;
- ATMOSPHERIC PROCESSES