Abstract:
Objectives Atmospheric weighted average temperature Tm is essential for calculating water vapour conversion factor and atmospheric precipitation.
Methods Based on the global geodetic observing system(GGOS) Atmosphere Tm grid data and European centre for medium-range weather forecasts (ECMWF) 2 m temperature data from 2007 to 2017, a Tm model (qTm) suitable for Australia was established and the seasonal and daily variation of Tm residuals was taken into account. In addition, GGOS Atmosphere Tm grid data and radiosonde data in 2018 were selected to evaluate the model.
Results The results reveal that the qTm model is more accurate and applicable in the Australian region. Compared with GGOS Atmosphere Tm, the annual average Bias and RMSE(root mean square error) of the qTm model are -0.31 K and 1.97 K, respectively. While compared to the GPT2w(global pressure and temperature 2 wet)-1 and GPT2w-5, RMSE of qTm model increased by 21.8% and 25.9%, respectively. qTm model values are more consistent with sounding integral values, and the model's annual average Bias and RMSE are -0.44 K and 2.45 K, respectively. Compared with GPT2w-1 and GPT2w-5, they increased by 10.2% and 11.8%, respectively.
Conclusions The qTm model can provide accurate Tm values for the Australian region and is a basis for the region's atmospheric moisture analysis and El Niño studies.