2 Materials and Methods
2.1 CYGNSS
The CYGNSS constellation of 8 satellites collects GPS radar signals
scattered on the forward (specular) direction to infer surface wind
speeds, even through heavily precipitating clouds over the
subtropical oceans (±38° latitude) (Ruf et al., 2019). CYGNSS surface
wind speeds are used in conjunction with the ERA5 reanalysis to create
an observational surface heat flux product (Crespo et al., 2019). We use
CYGNSS Science Data Record (SDR) 2.0 flux data from August 2018 to
December 2022. Our analysis is ocean-only. The fluxes are provided for
specular points each of the 8 satellites observe at any given time.
Preliminary assessment of CYGNSS Latent Heat Flux (LHF) accuracy against
buoys in the tropical oceans indicates a slight positive bias of 38±35
Wm2 (Ruf et al., 2022), comparable to that of some
more mature products (Bentamy et al., 2017).