The Department of Defense (DoD)-sponsored Space Test Program-Houston 8 (STP-H8) mission, carrying Jet Propulsion Laboratory (JPL)'s Compact Ocean Wind Vector Radiometer (COWVR) and Temporal Experiment for Storms and Tropical Systems (TEMPEST), aims to demonstrate new low-cost microwave sensor technologies for weather applications.
COWVR and TEMPEST were launched on Dec.21, 2021 at 5:07am EST from the Kennedy Space Center to the International Space Station (ISS) as part of SpaceX’s 24th Commercial Resupply Mission (CRS-24). The instruments were deployed to the JEM-EF module of the ISS to commence a planned 3-year operation.
NASA contributions to the mission: NASA funded the development of TEMPEST-D and its spare copy, which became TEMPEST-H8, through the Earth Ventures Technology Demonstration Program. NASA also provided the launch as a part of the ISS crew resupply missions. A little more loosely tied is that COWVR uses receiver designs from Jason-3, which was an instrument originally developed by JPL for NASA to support the Jason altimeter mission.
COWVR and TEMPEST together provide simultaneous measurements of various variables at the air-sea interface and in the atmosphere.
Specific geophysical retrievals from COWVR include Ocean surface wind vector, precipitable water vapor, cloud liquid water, and precipitation rate; those from TEMPEST include atmospheric vertical water vapor profile, convective precipitation, and ice water path. Both COWVR and TEMPEST provide brightness temperature measurements at their respective frequencies. The real-time data stream of COWVR and TEMPEST measurements will be delivered via the Tracking and Data Reply Satellite System (TDRSS) with a latency of minutes. The data products for different variables and their spatial resolutions, expected uncertainties, and producers are listed in Table 2.
Table 2. Data products from COWVR and TEMPEST
Wind speed < 6 m/s
Wind speed between 6 & 12 m/s
> 12 m/s
Precipitable water vapor
< 0.3 cm
Cloud liquid water
Ice water path
<50% for IWP>200g/m2
Water vapor profile
*NASA funded development
PO.DAAC is NASA’s designated archive and distribution center for the STP-H8 mission data, with the science data to be provided in HDF-5 format. Public release of data is planned in late 2022, following the calibration/validation period. This new mission will supplement the PO.DAAC archive with additional relevant data (e.g., for ocean-surface vector winds) that are non-sun-synchronous, thereby enhancing existing measurements from sun-synchronous sensors/platforms.
Table 3. COWVR and TEMPEST datasets at PO.DAAC
The key characteristics of the COWVR and TEMPEST instruments are listed in Table 1.
Table 1. COWVR and TEMPEST sensor characteristics:
18.7, 23.8, 33.9 GHz
Full polarizations for each frequency
18.7 GHz: 30x19 km;
23.8 GHz: 23x15 km;
33.9 GHz: 16x10 km
89, 166, 176, 180, 182 GHz
166-182 GHz: 13 km
*H: Horizontal; V: Vertical; P: +45°; M: -45°; L: Left-hand circular; R: Right-hand circular
A Science Working Group (SWG) named Air-Sea interface and Atmospheric Profile observatory (ASAP) was formed in early 2021 to provide community leadership for advancing the research and applications using COWVR and TEMPEST measurements. The ASAP-SWG is composed of scientists from NASA (JPL, GSFC, MSFC), DoD, NOAA, universities, private sector, and Météo France. Tony Lee (JPL), Ben Ruston (JCSDA), Clark Rowley (NRL) and Hui Su (JPL) serve as ASAP-SWG co-chairs.
With NASA’s support, members of the ASAP-SWG will also develop products for water vapor profile, precipitation rate, and ice water path using the STP-H8 mission measurements. The simultaneous measurements of air-sea interface and atmospheric profiles present significant advantages for research and applications in the areas of storm forecasting, weather and atmospheric dynamics, air-sea interactions, climate sciences and model improvements.