| Paper: | TH-P2.4 |
| Session: | Atmospheric Applications of Radiometry I |
| Time: | Thursday, March 29, 16:40 - 17:00 |
| Presentation: |
Oral
|
| Topic: |
Clouds and precipitation: |
| Title: |
Simulation of Time-Resolved Observations of a Hailstorm by a TEMPEST Satellite Constellation |
| Authors: |
Chandrasekar Radhakrishnan; Colorado State University | | |
| | Chandrasekar Venkatachalam; Colorado State University | | |
| | Steven C. Reising; Colorado State University | | |
| Abstract: |
The Temporal Experiment for Storms and Tropical Systems (TEMPEST) is a proposed 6U CubeSat mission to directly measure the time evolution of clouds and study the transition from non-precipitating to precipitating cloud processes using high-temporal resolution observations. The full TEMPEST constellation mission consists of five identical 6U-Class CubeSats deployed in the same orbital plane with 5-minute spacing and utilizes the technology demonstrated during the TEMPEST-D (“D” for demonstration) satellite mission, scheduled for launch in May 2018. TEMPEST millimeter-wave radiometers measure at five millimeter-wave frequencies from 89 GHz to 182 GHz, with the capability to observe important changes as precipitation begins and ice forms inside the storm.
This paper focuses on simulation of the temporal variability of observations at the TEMPEST millimeter-wave frequencies over a convective event in the U.S. southern Great Plains that was also observed by a ground-based polarimetric radar. The Weather Research and Forecasting (WRF) model is used to simulate the hail storm that occurred over the Dallas Fort Worth (DFW) area. The ground-based polarimetric radar reflectivity and radial velocity data are assimilated into WRF to improve the space-time specificity of the model simulation. Assimilation of the radar data ensures the spatial and temporal specificity of the actual event. Vertical profiles of atmospheric variables and hydrometers are generated from the WRF model. Radiance observations are estimated as brightness temperatures (TBs) at the TEMPEST frequencies using a radiative transfer model (RTM), along with the temporal variability. This research is primarily focused on understanding the temporal variability of TEMPEST observations over a hail storm. The assimilation of KFWS (NEXRAD) radar data is used to enhance the WRF simulation. Subsequently, the spatial and temporal specificity of the WRF-simulated storm is closer to the one observed from ground radars than without assimilation. The model simulations compare fairly well to the Collaborative Adaptive Sensing of the Atmosphere (CASA) radar network Quantitative Precipitation Estimation (QPE). The temporal variability of the TBs at the TEMPEST frequencies demonstrates that the high-frequency channels provide sufficient variability in time that can be potentially observed and used in retrievals. This paper shows quantitatively the change in TBs for a hail storm in which the model output is controlled by assimilating high-resolution, dual-polarization radar data, which represent cloud and precipitation microphysics fairly accurately.
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