Analysis on the Periodic Characteristics of Ground Temperature Error in Reanalysis Data in Central and Eastern China

Abstract

Ground temperature is an important variable affecting the thermal interaction between atmosphere and land.However， due to its strong small-scale variation characteristics， the study of ground temperature variation has been restricted by the insufficient spatial and temporal resolution of the observations.Based on the observation data of automatic stations with high spatial-temporal resolution in China in January and July 2019， the reproduction ability of two reanalysis data， GFS （Global Forecast System） and era5 （European Center for medium range weather forecasts fifth reanalysis data）， to the variation characteristics of ground temperature in eastern China is analyzed.The results show that the surface 2m temperature and ground temperature of the two reanalysis data have obvious diurnal variation characteristics， but the difference between the observation and the reanalysis data has obvious diurnal characteristics.Further analysis shows that the diurnal characteristics of the difference is mainly due to the systematic phase bias of the two reanalysis data in the simulation of the diurnal variation of ground temperature in China， and the phase bias also has an obvious longitude dependence.The possible causes of the diurnal variation of the errors are also discussed by comparative analysis of the errors in each latitude band.

Keywords

• surface temperature
• diurnal variation
• periodic error