by Douglas Messier
NOAA will purchase radio occultation (RO) data from commercial companies after determining that the measurements are useful in improving weather forecasting.
In a report released last week, NOAA said measurements provided by Spire Global and GeoOptics satellites during the second round of the Commercial Weather Data Pilot (CWDP) program in 2018 and 2019 demonstrated the utility of commercial RO data.
“Based on the results of the technical evaluation of the data provided by two vendors in the CWDP Round 2 Pilot, NOAA has concluded that the commercial sector is capable of providing the quality of data needed to help support NOAA’s operational weather forecasting needs,” the agency said. “As a result, NOAA is proceeding with plans to acquire commercial RO data for operational use.”
In the pilot program, instruments on the companies’ satellites measured how radio signals from Global Navigation Satellite System (GNSS) transmitters refracted or bent as they traveled through the Earth’s occulting atmosphere.
“Collecting these measurements for a full occultation through the atmosphere provides a vertical profile of bending angles, from which profiles of physical quantities such as temperature, humidity, and ionospheric electron density can be retrieved,” NOAA said. “These data primarily feed numerical weather prediction (NWP) models that support weather forecasts, and also support space weather applications.”
NOAA added that commercial satellites can improve forecasting by providing measurements from areas of the globe where coverage is sparse.
“Studies indicate that increasing the quantity of RO data, particularly in orbits and times not served by government systems, would further improve forecasts. Ionospheric observations from RO sensors also enhance space weather situational awareness, revealing variations in the ionosphere that impact GNSS performance and radio communications,” the agency said.
NOAA launched the CWDP program in 2016 with contracts awarded to GeoOptics and Spire. GeoOptics was not able to launch satellites in time to provide RO data. Spire provided data that only partially met the contract requirements.
NOAA said the results were promising enough to launch a second round of the program with contracts awarded to GeoOptics, PlanetiQ and Spire Global. PlanetiQ was unable to launch its satellites in time to provide the required data.