Evaluation of Parameters Related to Heat Fluxes for Observations in the Northwest Atlantic during ATOMIC/EUREC4A Journal of Atmospheric and Oceanic Technology

The Atlantic Tradewind Ocean–Atmosphere Mesoscale Interaction Campaign (ATOMIC) and Elucidating the Role of Clouds Circulation Coupling in Climate Campaign (EUREC4A) were joint U.S./EU campaigns in January–February 2020 that sought to investigate atmospheric shallow convection and air–sea interaction during the winter season in the northwest tropical Atlantic. This study evaluates bulk surface turbulent heat fluxes and the mean state parameters used to calculate them, such as 2-m surface air temperature Ta and humidity qa, 10-m wind speed U10, and sea surface temperature (SST), from 15 platforms during the two joint field campaigns. These four state parameters were adjusted for all platforms to a calibrated reference ATOMIC platform, the NOAA Ship Ronald H. Brown. Results show a reduction in the mean latent heat flux HL of 11.50 W m−2 and an increase in the mean sensible heat flux HS of 1.2 W m−2. Heat fluxes from the fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5) and Objectively Analyzed Air–Sea Fluxes (OAFlux) satellite-derived blended datasets were evaluated with the heat fluxes calculated from the corrected in situ state parameters. ERA5 and OAFlux had higher wind speeds than ATOMIC resulting in 12.51 W m−2 more HL for ERA5. However, OAFlux had 10.47 W m−2 less HL which is attributed to its 0.93 g kg−1 wet bias in qa. OAFlux and ERA5 HS were higher than observations (3.81 and 4.49 W m−2, respectively). The diurnal cycle of ERA5 agreed well with ATOMIC observations of U10, but phase differences, particularly in the afternoon, were evident for Ta and qa. Grant no. NA22OAR4320151-T3-01S005 Grant no. NOAA-OAR-CPO-2021-2006389