A Facility for Near-Real Time Estimation and Evaluation of Diurnal Warming of the Sea Surface

Diurnal changes in the sea surface temperature (SST) complicate the generation and interpretation of daily SST analyses. Observations from different times through the day and different effective measurement depths are all influenced by diurnal warming to differing amounts, and generation of foundation SST analyses requires some approach to treating the effects of diurnal warming. While multiple SST analyses currently exist, only limited information is available on the diurnal variations that occur on top of the daily estimates on a global scale. Similarly, little systematic information is available on differences in accuracy of currently available methods for estimating diurnal warming.

To address these factors, a facility has been implemented at the NOAA Earth System Research Laboratory to provide and evaluate hourly estimates of the amplitude of diurnal warming computed from multiple different models based on forcing data from numerical weather prediction analyses. The facility currently obtains daily heat and momentum flux forcing data from the NOAA Global Forecast System (GFS) model as well as wave parameters from the Wave Watch III model. Data over a two day period are used to force multiple numerical models for the diurnal warming amplitude. Estimates of the amplitude are provided hourly from each model relative to several depths including the skin layer, 20 cm and 1 m. All data are presented via a web-based interface and are available for download. Comparison of the model estimates with available observational measurements from geostationary satellites is also provided. This presentation demonstrates the capabilities of the facility focusing on evaluation of the accuracy of the modeled warming estimates.