Inland lake temperature initialization via cycling with atmospheric data assimilation

Application of lake models coupled within earth-system prediction models, especially for short-term predictions from days to weeks, requires accurate initialization of lake temperatures.   Here, we describe a lake initialization method by cycling within an hourly updated weather prediction model to constrain lake temperature evolution.   We compare these simulated lake temperature values with other estimates from satellite and in situ and interpolated-SST data sets for a multi-month period in 2021.   The lake cycling initialization, now applied to two operational US NOAA weather models, was found to decrease errors in lake temperature from as much as 5-10K (using interpolated-SST data) to about 1-2 K (comparing with available in situ and satellite observations.