A diurnally varying sea surface temperature dataset using a next generation parameterization

Many current sea surface temperature (SST) climatologies focus on a bulk or a foundation temperature, such as commonly derived from bucket ship measurements and the Reynolds SST satellite analysis that are optimized to those measurements. However, the international SeaFlux project has noted and shown that SST datasets used to compile flux climatologies need to resolve the diurnal cycle, because diurnal variability can substantially impact the fluxes over large regions of the global oceans. Thus, the diurnally varying sea surface temperature product will be skin temperature product. Using the Pathfinder SST Version 5 product as a basis for the diurnally varying product, the Pathfinder data is quality controlled. A pre-dawn SST product will be created as the base or foundation to superimpose diurnal variability. The diurnal sea surface temperature (dSST) is defined as the positive difference between maximum daily SST and the minimum daily SST, which generally occurs just before dawn. Empirical approaches for the use of diurnal warming for filling in the satellite fields have shown reasonable quality as well, while requiring the use of fewer inputs (generally wind speed and peak solar radiation), therefore limiting additional sources of uncertainty. A next generation empirical approach to diurnally variability is being explored, including improvements by the integrated solar heating, inclusion of length of day variability for improving the timing of the peak diurnal warming, and the use of higher-temporal wind sampling as opposed to a daily-averaged value. Starting with the creation of a pre-dawn SST, the diurnal cycle of the SST is superimposed. As such, SST products with hourly and three-hourly temporal resolution will be created. To provide the best possible spatial resolution with current limitations, a quarter degree grid will be used. The new diurnally varying SST dataset will be used in turbulent flux calculations to explore the impact of the inclusion of an improved diurnally varying SST product on air-sea fluxes.