Determination of land surface heat fluxes over heterogeneous landscape of the Tibetan Plateau by using the MODIS and in situ data

Abstract

Abstract. In this study, a parameterization methodology based on MODIS (Moderate Resolution Imaging Spectroradiometer) and in situ data is proposed and tested for deriving the regional surface reflectance, surface temperature, net radiation flux, soil heat flux, sensible heat flux and latent heat flux over heterogeneous landscape. As a case study, the methodology was applied to the Tibetan Plateau area. Four images of MODIS data (30 January 2007, 15 April 2007, 1 August 2007 and 25 October 2007 were used in this study for the comparison among winter, spring, summer and autumn. The derived results were also validated by using the "ground truth" measured in the stations of the Tibetan Observation and Research Platform (TORP). The results show that the derived surface variables (surface reflectance and surface temperature) and surface heat fluxes (net radiation flux, soil heat flux, sensible heat flux and latent heat flux) in four different seasons over the Tibetan Plateau area are in good accordance with the land surface status. These parameters show a wide range due to the strong contrast of surface features over the Tibetan Plateau. Also, the estimated land surface variables and surface heat fluxes are in good agreement with the ground measurements, and all their absolute percent difference (APD) is less than 10 % in the validation sites. It is therefore concluded that the proposed methodology is successful for the retrieval of land surface variables and surface Correspondence to: Y. M. Ma (ymma@itpcas.ac.cn) heat fluxes using the MODIS and in situ data over the Tibetan Plateau area. The shortage and further improvement of the methodology were also discussed.

Comparison of satellite-based evapotranspiration estimates over the Tibetan Plateau

“…The knowledge of ET is essential for the study of land-atmosphere interactions, and assessment of the impacts of and feedbacks to the global change (Shi and Liang, 2014). In order to characterise the distribution of ET over the TP, different methods using micrometeorological measurements (Yang et al, 2003;Lee et al, 2012;Chen et al, 2013b;Zhang et al, 2007), remote sensing products (Ma et al, , 2006Chen et al, 2013a) and the combined use of both data sources (Ma et al, 2003(Ma et al, , 2011You et al, 2014) have been investigated over the last decades. In addition, land surface models have also been applied to simulate ET over the TP (Gerken et al, 2012;Yang et al, 2009).…”

Combining MODIS, AVHRR and in situ data for evapotranspiration estimation over heterogeneous landscape of the Tibetan Plateau

“…(1) the land surface heat fluxes has been outlined in the paper of Ma et al (2011), though it differs from the determination of surface reflectance, surface temperature, surface emissivity, vegetation coverage etc. used in this study.…”

Land-atmosphere interactions and their relationships to the Asian monsoon in the Tibetan plateau

“…The physical quantities of the land surface which may possess anomalous atmospheric forcing or climate memory effects can be but not limited to: (1) Vegetation indices, such as Normalized Difference Vegetation Index (NDVI), vegetation coverage, (2) land surface temperature (LST), (3) albedo, (4) soil moisture, (5) water vapour content, (6) surface energy balance components. The above parameters are also among the most important land surface parameters for describing land surface features.…”

“…This method will be investigated to derive LST from AVHRR data. (3)(4)(5)(6)(7)(8)(9) Where 4 T and 5 T are brightness temperature of band 4 and band 5 for AVHRR; W is water vapour content and ε is average emissivity of band 4 and band 5.…”

“…The largest variation in latent heat flux is found in the north, northeast, and southwest of the TP. (6) Because of the decreasing wind speed and the diminishing ground-air temperature difference, the sensible heat flux on the TP has been decreasing at a rate of 3.37±2.19 Wm -2 per decade according to a bulk aerodynamic method. However, the latent heat flux tends to increase at a rate of 0.9 Wm -2 per decade.…”