CYGNSS Surface Heat Flux Product: Development and Initial Results

Latent and sensible heat fluxes (LHF and SHF, respectively) over the world’s oceans play an influential role in the genesis and evolution of various weather phenomena and events. The community’s main source of surface heat flux observations over the ocean have been through direct in-situ observations. While this will continue to be the standard, in-situ observations can be limited in their spatial and temporal resolution. LHF and SHF estimated from remote sensing instruments can provide estimates where in-situ observations may not be available. However, previous instruments have often been limited as their signals are attenuated by precipitation, along with additional issues of coarse spatial and temporal resolution, especially observations around the tropical oceans from polar orbiting satellites.

The NASA Cyclone Global Navigation Satellite System (CYGNSS) is a constellation of eight small satellites providing estimates of surface winds over the tropical and subtropical oceans, providing a higher temporal and spatial sampling in this part of the globe. Since CYGNSS uses the GPS L1 channel, its signal is less sensitive to heavy precipitation as well. By combing the CYGNSS winds with thermodynamic variables from other sources (e.g. MERRA-2), we have developed and released to the public the CYGNSS Surface Heat Flux Product (CYGNSS Fluxes for short). This product provides LHF and SHF estimates for the entire CYGNSS mission (18 March 2017-present) and was validated with buoy data across the tropical and subtropical oceans. The aim of the CYGNSS Fluxes is to complement existing surface heat flux products and to aid the scientific community’s understanding of surface heat fluxes and their role in various weather events. These can include, but not limited to, tropical and extratropical cyclones, large-scale weather patterns (e.g. MJO), and tropical convection. This presentation will highlight the development of the product, future version updates, as well as some initial results.