The Department of Defense (DoD)-sponsored Space Test Program-Houston 8 (STP-H8) mission, carrying Jet Propulsion Laboratory (JPL)'s COWVR (Compact Ocean Wind Vector Radiometer) and TEMPEST (Temporal Experiment for Storms and Tropical Systems) instruments, aims to demonstrate new low-cost microwave sensor technologies for weather applications. Together COWVR and TEMPEST provide measurements used to derive spatially coincident wind vector and atmospheric water quantities. The simultaneous measurements of air-sea interface and atmospheric profiles present significant advantages for research and applications in storm forecasting, weather and atmospheric dynamics, air-sea interactions, climate sciences, and model improvements.
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 three-year operation (potentially extended five years as of 2025). The real-time stream of COWVR and TEMPEST measurements will be delivered via the Tracking and Data Reply Satellite System (TDRSS) with a latency of minutes. The first public release of data is planned in early 2024, following the calibration/validation period.
The development of TEMPEST-D and its spare copy, which became TEMPEST-H8, was funded by NASA through the Earth Ventures Technology Demonstration Program. NASA also provided the launch as a part of the ISS crew resupply missions. COWVR uses receiver designs from Jason-3, which was an instrument originally developed by JPL for NASA to support the Jason altimeter mission. 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.
Both COWVR and TEMPEST provide brightness temperature measurements at their respective frequencies, and the first set of derived physical variables include ocean surface winds and column-integrated water quantities (cloud liquid water, precipitable water vapor). Additionally, the Air-Sea interface and Atmospheric Profile observatory Science Working Group (ASAP-SWG) was formed in early 2021 to provide community leadership for advancing research and applications with COWVR and TEMPEST measurements. With NASA's support, the ASAP-SWG will also develop products for water vapor profile, precipitation rate, and ice water path using the STP-H8 measurements. PO.DAAC is the designated data archive and distribution center, with science data provided in HDF-5 format. These measurements supplement the PO.DAAC archive with non-sun-synchronous wind and water data, enhancing existing measurements from sun-synchronous sensors/platforms. The anticipated data products are listed in Table 1.
Table 1. Anticipated data products from COWVR and TEMPEST
Wind vector (speed and direction)
30 km
Wind speed < 6 m/s
Wind speed between 6 & 12 m/s
Wind speed
> 12 m/s
JPL
38°
16°
8°
1 m/s
Precipitable water vapor
< 0.3 cm
Cloud liquid water
0.05 mm
Precipitation rate
15 km
TBD
*CSU/JPL
Ice water path
<50% for IWP>200g/m2
*CSU
Water vapor profile
15%
Brightness temperature
13-30 km
< 0.3K
*NASA funded development
Table 2. COWVR and TEMPEST key sensor characteristics:
COWVR
18.7, 23.8, 33.9 GHz
Full polarizations for each frequency
(*H,V,P,M,L,R)
<0.3K
18.7 GHz: 30x19 km;
23.8 GHz: 23x15 km;
33.9 GHz: 16x10 km
890 km
TEMPEST
89, 166, 176, 180, 182 GHz
<0.5K
(at nadir)
89 GHz:
25 km;
166-182 GHz: 13 km
1400 km
*H: Horizontal; V: Vertical; P: +45°; M: -45°; L: Left-hand circular; R: Right-hand circular
Documents provided here include information on the general COWVR-TEMPEST project. A complete set of documents specific to each data product (if further resources are available) can be found on that product's landing page.
Brown, Shannon, Paolo Focardi, Amarit Kitiyakara, Frank Maiwald, Lance Milligan, Oliver Montes, Sharmila Padmanabhan et al. "The COWVR Mission: Demonstrating the capability of a new generation of small satellite weather sensors." In 2017 IEEE Aerospace Conference, pp. 1-7. IEEE, 2017.
Brown, Shannon, Paolo Focardi, Amarit Kitiyakara, Frank Maiwald, Oliver Montes, Sharmila Padmanabhan, Richard Redick, D. Russel, and James Wincentsen. "The compact ocean wind vector radiometer: A new class of low-cost conically scanning satellite microwave radiometer system." In Proc. IEEE Geosci. Remote Sens. Soc.(IGRSS), 35th Can. Remote Sens. Soc.(CSRS), pp. 1-3. 2014.
Farrar, Spencer, Steven Swadley, Shannon Brown, Eric Simon, Sayak Biswas, David Kunkee, and Kieran Smith. "An Initial on-Orbit Performance Assessment of the Compact Ocean Wind Vector Radiometer (COWVR)." In IGARSS 2024-2024 IEEE International Geoscience and Remote Sensing Symposium, pp. 6277-6281. IEEE, 2024.
