Retrieval and Validation of Land Surface Temperature with General Split-window Algorithm from NOAA-18(N) AVHRR/3 Data

Abstract

On the basis of the atmospheric radiative transfer theory,land surface temperature(LST) was retrieved from NOAA-18(N) AVHRR/3 cloud-free data using a general split-window(GSW) algorithm.A simulated database including the thermal infra-red channels(Channel 4 with spectral range 10.3-11.3μm and Channel 5with spectral range11.5-12.5μm) radiance observed at the satellite level was established with the atmospheric radiative transfer model MODTRAN 4.It covers various land surface types and atmospheric conditions.Then the coefficients of the GSW were determined by grouping the LST,the atmospheric water vapor content(WVC),the land surface emissivity(LSE),and the viewing zenith angle(VZA) by several sub-ranges.Results showed that the root mean square error(RMSE) between the estimated and actual LST is less than 1.0K when the VZA is less than 30° or the WVC is less than 3.5 g/cm2.The RMSE is less than 1.5K when the VZA is less than 45° and the WVC is less than 5.5 g/cm2.In addition,the proposed algorithm was applied to the NOAA-18(N) AVHRR/3 data to retrieve LSTs.The LSE was determined by using the NDVI thresholds method,and the WVC was estimated with the transmittance ratio method proposed by Li et al.(2003).Finally,the field measured data of the USFlux stations were used to validate the retrieved LST.The results showed that the RMSE is less than 1.8K.