Developing a Surface Heat Flux Product for the CYGNSS Satellite Mission

Latent and sensible heat fluxes at the surface play a critical role in Earth’s weather and climate, as they transport mass, momentum, and energy between the surface and lower troposphere. Given their importance, frequent and spatially contiguous observations, especially over the oceans, of these heat fluxes are critical in order to better understand their relation to various weather phenomena. While sensible and latent heat fluxes can be estimated from in-situ measurements (e.g., buoys), spatial and temporal coverage is limited over the world’s oceans. Additionally, surface heat fluxes estimated using data collected by previous satellite missions are limited by infrequent temporal sampling and signal attenuation in regions of precipitation.

Early-on orbit results from the Cyclone Global Navigation Satellite System (CYGNSS) have shown its ability to estimate latent and sensible heat fluxes along its orbit over the tropical and sub-tropical oceans. Since surface winds are critical in estimating surface heat fluxes, the improved wind speed measurements from CYGNSS have the potential to contribute to near continuous estimates of surface heat fluxes in nearly all weather conditions. Given promising early results, and interest from the scientific community, we are developing a Level-2 Surface Heat Flux product for the entire CYGNSS mission. This product will utilize CYGNSS’s Level-2 surface wind speed observations, along with satellite and reanalysis sources for temperature and specific humidity, and will estimate surface heat fluxes using the latest version of the Coupled Ocean-Atmosphere Response Experiment (COARE) algorithm. Since surface fluxes play a crucial role in tropical convection, convectively coupled waves, and low-latitude extratropical cyclones, we expect that the development of this product will aid the scientific community in their understanding of surface heat flux influences on Earth’s weather and climate.