A Comprehensive Evaluation of 4-Parameter Diurnal Temperature Cycle Models with In Situ and MODIS LST over Alpine Meadows in the Tibetan Plateau

Yaping Chang,Qiudong Zhao,Shiqiang Zhang,Yongjian Ding

doi:10.3390/rs12010103

Abstract

Diurnal variation of land surface temperature (LST) is essential for land surface energy and water balance at regional or global scale. Diurnal temperature cycle (DTC) model with least parameters and high accuracy is the key issue in estimating the spatial–temporal variation of DTC. The alpine meadow is the main land cover in the Tibetan Plateau (TP). However, few studies have been reported on the performance of different DTC models over alpine meadows in the TP. Four semi-empirical types of DTC models were used to generate nine 4-parameter (4-para) models by fixing some of free parameters. The performance of the nine 4-para DTC models were evaluated with four in situ and MODIS observations. All models except GOT09-dT-ts (dT means the temperature residual between T0 and T (t→∞); ts means the time when free attenuation begins) had higher correlation with in situ data (R2 > 0.9), while the INA08-ts model performed best with NSE of 0.99 and RMSE of 2.04 K at all sites. The GOT09-ts-τ (τ is the total optical thickness), VAN06-ts-ω1 (ω1 means the half-width of the cosine term in the morning), and GOT01-ts models had better performance, followed by GOT09-dT-τ, GOT01-dT, and VAN06-ts-ω2 (ω2 means the half-width of the cosine term in the afternoon) models. All models had higher accuracy in summer than in other seasons, while poorer performance was produced in winter. The INA08-ts model showed best performance among all seasons. Models with fixing ts could produce higher accuracy results than that with fixing dT. The comparison of INA08-ts model driven by in situ and Moderate Resolution Imaging Spectroradiometer (MODIS) data indicated that the simulation accuracy mainly depended on the accuracy of MODIS LST. The daily maximum temperature generated by the nine models had high accuracy when compared with in situ data. The sensitivity analysis indicated that the INA08-dT and GOT09-dT-ts models were more sensitive to parameter dT, while all models were insensitive to parameter ts, and all models had weak relationship with parameters ω and τ. This study provides a reference for exploring suitable DTC model in the TP.

Highlights

Land surface temperature (LST) is a key and basic parameter for land surface energy balance and water balance at regional and global scales [1,2]
Since LST is a critical parameter for calculating land surface energy balance and water-heat budget [16], it is very important to evaluate the different diurnal temperature cycle (DTC) models in Tibetan Plateau (TP)
Four popular semi-physical (SEM) DTC methods, including GOT01 model developed by Göttsche and Olesen [18], VAN06 model proposed by Van den Bergh et al [29], INA08 model founded by Inamdar et al [19] and GOT09 model developed by Göttsche and Olesen [22], were chosen for experiment on reducing the number of free parameters to four

Summary

Introduction

Land surface temperature (LST) is a key and basic parameter for land surface energy balance and water balance at regional and global scales [1,2]. The diurnal LST variation is crucial for meteorological, hydrological and climatological research and applications [3,4,5,6]. It is a very sensitive parameter to describe the characteristics of surface energy balance, surface thermal inertia, and surface water-heat budget [4]. Since LST is a critical parameter for calculating land surface energy balance and water-heat budget [16], it is very important to evaluate the different DTC models in TP

Methods

Results

Conclusion