Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 20, 3263-3275, 2016
https://doi.org/10.5194/hess-20-3263-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
11 Aug 2016
Cloud tolerance of remote-sensing technologies to measure land surface temperature
Thomas R. H. Holmes1,2, Christopher R. Hain3, Martha C. Anderson1, and Wade T. Crow1 1Hydrology and Remote Sensing Lab., USDA-ARS, Beltsville, MD, USA
2Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
3Earth Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
Abstract. Conventional methods to estimate land surface temperature (LST) from space rely on the thermal infrared (TIR) spectral window and is limited to cloud-free scenes. To also provide LST estimates during periods with clouds, a new method was developed to estimate LST based on passive-microwave (MW) observations. The MW-LST product is informed by six polar-orbiting satellites to create a global record with up to eight observations per day for each 0.25° resolution grid box. For days with sufficient observations, a continuous diurnal temperature cycle (DTC) was fitted. The main characteristics of the DTC were scaled to match those of a geostationary TIR-LST product.

This paper tests the cloud tolerance of the MW-LST product. In particular, we demonstrate its stable performance with respect to flux tower observation sites (four in Europe and nine in the United States), over a range of cloudiness conditions up to heavily overcast skies. The results show that TIR-based LST has slightly better performance than MW-LST for clear-sky observations but suffers an increasing negative bias as cloud cover increases. This negative bias is caused by incomplete masking of cloud-covered areas within the TIR scene that affects many applications of TIR-LST. In contrast, for MW-LST we find no direct impact of clouds on its accuracy and bias. MW-LST can therefore be used to improve TIR cloud screening. Moreover, the ability to provide LST estimates for cloud-covered surfaces can help expand current clear-sky-only satellite retrieval products to all-weather applications.


Citation: Holmes, T. R. H., Hain, C. R., Anderson, M. C., and Crow, W. T.: Cloud tolerance of remote-sensing technologies to measure land surface temperature, Hydrol. Earth Syst. Sci., 20, 3263-3275, https://doi.org/10.5194/hess-20-3263-2016, 2016.
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Short summary
We test the cloud tolerance of two technologies to estimate land surface temperature (LST) from space: microwave (MW) and thermal infrared (TIR). Although TIR has slightly lower errors than MW with ground data under clear-sky conditions, it suffers increasing negative bias as cloud cover increases. In contrast, we find no direct impact of clouds on the accuracy and bias of MW-LST. MW-LST can therefore be used to improve TIR cloud screening and increase sampling in clouded regions.
We test the cloud tolerance of two technologies to estimate land surface temperature (LST) from...
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