Investigating soil moisture-climate interactions in a changing climate: A review

A remote sensing surface energy balance algorithm for land (SEBAL)-1. Formulation

Improvements to a MODIS global terrestrial evapotranspiration algorithm

https://researchweb.iiit.ac.in/~sai.deepak/lectures/14.%20Thermal%20remote%20sensing%20of%20urban%20climates%202003%20Voogt%20and%20Oke.pdf

Thermal remote sensing of urban climates

 A Surface Energy Balance System (SEBS) is proposed for the estimation of atmospheric turbulent fluxes and evaporative fraction using satellite earth observation data, in combination with meteorological information at proper scales SEBS consists of: a set of tools for the determination of the land surface physical parameters, such as albedo, emissivity, temperature, vegetation coverage etc, from spectral reflectance and radiance measurements; a model for the determination of the roughness length for heat transfer; and a new formulation for the determination of the evaporative fraction on the basis of energy balance at limiting cases Four experimental data sets are used to assess the reliabilities of SEBS Based on these case studies, SEBS has proven to be capable to estimate turbulent heat fluxes and evaporative fraction at various scales with acceptable accuracy The uncertainties in the estimated heat fluxes are comparable to in-situ measurement uncertainties Keywords: Surface energy balance, turbulent heat flux, evaporation, remote sensing

/pdf/the-surface-energy-balance-system-sebs-for-estimation-of-5guqrebqb3.pdf

The Surface Energy Balance System (SEBS) for estimation of turbulent heat fluxes

A remote sensing surface energy balance algorithm for land (SEBAL).

Water management emphasis tends to shift from supply augmentation to limiting water consumption. Spatio-temporal information on actual evapotranspiration (ET) helps users to better understand evaporative depletion and to establish links between land use, water allocation, and water use. Satellite-based measurements, used in association with energy balance models, can provide the spatial distribution of ET for these linkages. This paper describes the major principles of the Surface Energy Balance Algorithm for Land (SEBAL) and summarizes its accuracy under several climatic conditions at both field and catchment scales. For a range of soil wetness and plant community conditions, the typical accuracy at field scale is 85% for 1 day and it increases to 95% on a seasonal basis. The accuracy of annual ET of large watersheds was found to be 96% on average. SEBAL has been applied in more than 30 countries worldwide, and the 26 research studies that were conducted over the past 10 years are now gradually being replaced by application studies (17 studies finished). A short case study in the Yakima River basin (Washington State) is presented as new material to demonstrate how ET from remote sensing can be used for evaluating water conservation projects.

SEBAL model with remotely sensed data to improve water-resources management under actual field conditions

https://jornada.nmsu.edu/bibliography/02-100.pdf

Temperature and emissivity separation from multispectral thermal infrared observations

estimated as being 112 Wm � 2 . The basin average sensible, latent and soil heat fluxes were estimated to be 80, 32, and 0 Wm � 2 , respectively. The average evapotranspiration (ET) and evaporative fraction were 1.2 mm d � 1 and 0.28, respectively. The basin wide ET was 496 6 16.8 km 3 yr � 1 . Monte Carlo analysis have indicated 3.4% error at 95% confidence interval for a dominant land use class. Results compared well with previously conducted soil moisture, lysimeter and Bowen ratio measurements at field scale (R 2 ¼ 0.70; RMSE ¼ 0.45 mm d � 1 ; RE ¼ –11.5% for annual ET). ET results were also compared against earlier remote sensing and modeling studies for various regions and provinces in Pakistan (R 2 ¼ 0.76; RMSE ¼ 0.29 mmd � 1 ;R E¼ 6.5% for annual ET). The water balance for all irrigated areas together as one total system in Pakistan and India (26.02 million ha) show a total ET value that is congruent with the ET value from the ETLook surface energy balance computations. An unpublished validation of the same ETLook model for 23 jurisdictional areas covering the entire Australian continent showed satisfactory results given the quality of the watershed data and the diverging physiographic and climatic conditions (R 2 ¼ 0.70; RMSE ¼ 0.31 mmd � 1 ;R E¼ –2.8% for annual ET). Eight day values of latent heat fluxes in Heibei (China) showed a good resemblance (R 2 ¼ 0.92; RMSE ¼ 0.04 mm d � 1 ;R E¼ 9.5% for annual ET). It is concluded that ETLook is a novel model that can be operationalized further—especially after improving the preprocessing of spaceborne soil moisture data. This preprocessing includes (1) downscaling of topsoil moisture from 25 to 1 km pixels, and (2) translation of topsoil moisture into subsoil moisture values.

/pdf/surface-energy-balance-and-actual-evapotranspiration-of-the-4zti8vndx5.pdf

Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model

In this study, a simple method is described and tested for deriving initial soil moisture fields for numerical weather prediction purposes using satellite imagery. Recently, an algorithm was developed to determine surface evaporation maps from high- and low-resolution satellite data, which does not require information on land use and synoptic data. A correction to initial soil moisture was calculated from a comparison between the evaporation fields produced by a numerical weather prediction model and the satellite algorithm. As a case study, the method was applied to the Iberian Peninsula during a 7-day period in the summer of 1994. Two series of short-term forecasts, initialized from a similar initial soil moisture field, were run in parallel: a control run in which soil moisture evolved freely and an experimental run in which soil moisture was updated daily using the simple assimilation procedure. The simple assimilation resulted in a decrease of the bias of temperature and specific humidity at 2-m height during the daytime and a small decrease of the root-mean-square error of these quantities. The results show that the surface evaporation maps, derived from the satellite data, contain a signal that may be used to assimilate soil moisture in numerical weather prediction models.

H. Pelgrum

Papers

A remote sensing surface energy balance algorithm for land (SEBAL).

SEBAL model with remotely sensed data to improve water-resources management under actual field conditions

Temperature and emissivity separation from multispectral thermal infrared observations

Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model

A New Methodology for Assimilation of Initial Soil Moisture Fields in Weather Prediction Models Using Meteosat and NOAA Data.