Using the COWVR+TEMPEST Sensor Combination to Complement Ocean Vector Winds with Precipitation

The Jet Propulsion Laboratory (JPL)'s Compact Ocean Wind Vector Radiometer (COWVR) and Temporal Experiment for Storms and Tropical Systems (TEMPEST) were developed to demonstrate new low-cost microwave sensor technologies for weather applications, while maintaining the same performances as more expensive instruments. COWVR and TEMPEST were launched on December 21, 2021 and installed on the International Space Station (ISS). Both COWVR and TEMPEST are currently operating nominally on-orbit.

COWVR is a fully polarimetric microwave radiometer, similar to WindSat, but with a much simpler design, operating at 18.7 GHz, 23.8 GHz, and 34.5 GHz. It has an un-blocked 360-degree scan, providing fore- and aft- observations (two-look), with a swath width of 890 km and a spatial resolution of 30x19 km at 18.7 GHz, 23x15 km at 23.8 GHz and 16x10 km at 33.9 GHz. It provides ocean surface wind vector retrievals along with precipitable water vapor in a very close proximity to precipitation, in addition to estimating cloud liquid water.

TEMPEST is a radiometer operating at five different frequencies ranging between 89 to 182 GHz. It has a spatial resolution of 25 km at 89 GHz and 13 km at 166-182 GHz, with a swath width of 1400 km. The joint 18-183 GHz range from COWVR+TEMPEST provides channel diversity similar to the NASA/JAXA Global Precipitation Measurement (GPM) Microwave Imager (GMI). This enables the capability to estimate water vapor and precipitation from selected COWVR+TEMPEST channel combinations, with the possibility to also measure precipitation structure profiles.

The combined dataset of near-surface wind vector and 3D water vapor estimates in the immediate vicinity of precipitation, together with the estimates of the precipitation structure of the storms, all revealed from the joint COWVR+TEMPEST mission, represents a unique opportunity to study hurricane structure, intensity and evolution as well as the surface fluxes around the storms. Combined emissivity measurements from COWVR and TEMPEST have also proved to be a valuable tool for the Tropical Cyclone operational community. They can give forecasters a look at the internal structure of a tropical cyclone and help them track the storm location and intensity, even if obscured by clouds. COWVR data will soon be available through the NASA Physical Oceanography Distributed Active Archive Center (PO.DAAC) and they are also expected to be ingested into the JPL Worldwide Ocean Wind (WOW) Portal (https://wow.jpl.nasa.gov/). For visualization and online analysis see the data portal (https://wow.jpl.nasa.gov/data-portal/).

We will present the synergy of COWVR+TEMPEST with particular focus on precipitation and wind vector retrievals. Examples in hurricane conditions will be shown that depict the precipitation extent in combination with the COWVR ocean vector wind fields outside and surrounding the precipitation area.