Evaluation of six land-surface diurnal temperature cycle models using clear-sky in situ and satellite data

Land surface temperature (LST) and its diurnal variation are vital to the study of land-atmosphere interactions and climate change. In this study, in situ and MSG-SEVIRI-derived LSTs were used to evaluate the performance of six published diurnal temperature cycle (DTC) models, i.e. the GOT01, GOT01_0, VAN06, JNG06, INA08, and GOT09 models. Two time intervals were considered: one is the entire day (sunrise to sunrise: Period A), and the other is from 09:00 A.M. to 03:00 A.M. on the following day (local solar time) (Period B). The results of Period A indicated that the JNG06 and GOT09 models performed best with overall root mean square errors (RMSEs) of 0.5 K. The GOT01, VAN06, and INA08 models performed similarly with overall RMSEs of 0.8 K. The GOT01_0 model performed the worst with an overall RMSE of 1 K. The results of Period B demonstrated that, except for the GOT01_0 model, the other models produced similar results with overall RMSEs of 0.4 K. However, if the width over the half-period of the cosine term (ω) in the GOT01_0, GOT01, and INA08 models was treated as a free parameter in the model fit during Period A, the performance of the GOT01 and INA08 models was significantly improved and attained the same level of accuracy as the JNG06 and GOT09 models. Although the accuracy of the GOT01_0 model was also improved to an overall RMSE of 0.8 K, with five free parameters, this model cannot accurately describe the variations of the LSTs around sunrise and noon.