SEBS for ILWIS OPEN 3.4 An interface for Surface Energy Balance in ILWIS Open Source (Jul 2007) Gabriel Parodi WRS - ITC INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION Environment for a SEB operation Work area and sensor/s definition. (frequency defines volume of operation) Requires ground and satellite pre- and post-processing near-real time. pre-processing: Satellite : download, calibration, geo-location, atm. Correction + extras Ground data: meteorological and land properties (depending on adopted SEB) processing: Calibration, validation? Running the selected SEB model and archiving (simplified). Post-processing Linking outputs to routines for information distribution in PLEIADeS. Assisting in reports and eventual performance From the operational point of view the algorithm itself is a “minor” problem. S. E. B. Models of Agricultural Areas from Earth Observation Data”, Lima, Perú, 13 March 2008 Lima. Perú. interface customization and complementary software requirements. Educational and transfer efforts if required.What we have and can offer to PLEIADeS Today: SEBS (Beta vesion) Interface in ILWIS Open source. B. E. 13 March 2008 . When required: Software algorithms adaptations. Models of Agricultural Areas from Earth Observation Data”. S. ILWIS is free of charge ('as-it-is‘) as open source software (binaries and source code) under the 52°North initiative (GPL license). http://52north. This software version is called ILWIS 3. Perú.4 open 1 July 2007. Models of Agricultural Areas from Earth Observation Data”. independent work is carried out to add methods and models in ILWIS. New release with updates (SEBS included): End March 2008. Lima. B. 13 March 2008 .ILWIS 3.4 Open. E.org/index. Since then.php?option=com_content&task=view &id=131&Itemid=155 S. 4 Open ILWIS is a remote sensing and GIS software. 13 March 2008 . Integrates image. editing. functional. ILWIS delivers a wide range of features including: import/export. It remains active after the open source release. S. Lima. Models of Agricultural Areas from Earth Observation Data”. digitizing. vector and thematic data in one unique and powerful package. both within and outside ITC. E. B. user-friendly has established a wide user community over the years of its development. analysis and display of data production of quality maps. Perú.ILWIS 3. Deadline (End of March) S. Interface done for educational purposes. Preprocess only MODIS This version was recently developed and testing was limited to WRS testing cases. Perú. It is in the final debugging state. SEBS module is documented in many articles Additional methods are selected from simplicity but they can be customized according to needs. Lima. B. Models of Agricultural Areas from Earth Observation Data”. E. Limited volume of data and no customization. 13 March 2008 .What is SEBS4ILWIS now? Adapted from SEBS in BEAM. B. Lima. 13 March 2008 . E. Perú.Pre-processing (optional) – 1 - S. Models of Agricultural Areas from Earth Observation Data”. Atmospheric correction visible (several sensors SMAC algorithm implemented in ILWIS) Land surface albedo Land surface emissivity Land surface temperature S. Lima.Pre-processing (optional) – 2 Characteristics Interface and models fully customizable (methods + Sensors) Today is customized for teaching and research purposes: MODIS pre-processing: Raw – radiances – reflectance. 13 March 2008 . B. Raw – radiances – brightness temperature. E. Perú. Models of Agricultural Areas from Earth Observation Data”. Lima. E. Perú. 13 March 2008 . B.Pre-processing (optional) – 3 - S. Models of Agricultural Areas from Earth Observation Data”. Models of Agricultural Areas from Earth Observation Data”. Perú.Pre-processing (optional) – 4 - S. Lima. B. E. 13 March 2008 . more methods/sensors can be customized. Perú. Models of Agricultural Areas from Earth Observation Data”. For daily routinely tasks requires adaptation. Brightness temperature: Inversion of Planck equation (standard). Land surface temperature: based on previous emissivity and Sobrino and Raissouni. S.to finally convert raw into radiance or reflectance. 2000. al (2003) and Carlson and Ripley (1997). E. Actual limitation: it is band by band. Land Surface albedo: weight method based on Liang. Land surface emissivity: based on PV-NDVI following Sobrino. SMAC: very convenient. 13 March 2008 . 2000. Only 2 atmospheric types.HEG: conversion to GEO TIFF of all necessary bands + angles . It was programmed for teaching purposes. easy. et.Importing to ILWIS . many sensors supported (thanks to authors). Improvements. B. Lima.Resampling the files .Get calibration coefficients with HDF explorer .Summary: pre-processing for MODIS Calibration: It works fine but requires 3 softwares: RAW image . 13 March 2008 . or H wet = Rn − G0 − λEwet H wet λEwet − λE λE Λr = = 1− λEwet λEwet H = (1 − Λ ) ⋅ (R n − G ) λ E = Λ ⋅ (R n − G ) ρC p es − e ⎞ ⎛ ⎟⎟ ⎜ = ⎜ (Rn − G0 ) − ⋅ γ ⎠ rew ⎝ ⎛ ∆⎞ ⎜⎜1 + ⎟⎟ ⎝ γ⎠ H − H wet Λr = 1− H dry − H wet Λ r ⋅ λ E wet Λ= = Rn − G Rn − G λE S. Lima. or H dry = Rn − G0 λEwet = Rn − G0 − H wet . 6(1). B. Perú. 2002. Models of Agricultural Areas from Earth Observation Data”. HESS.85-99 Rn = G0 + H + λE λEdry = Rn − G0 − H dry ≡ 0.SEBS Basic Equations Su. E. H − Hwet H dry − H wet Λ= λE Rn − G = Λ r ⋅ λEwet Rn − G No user interaction or decision affecting the results (Fc required!!). To evaluate evaporative fraction the energy balance is calculated at limiting wet & dry cases (used in SEBI). L calculated using set of non-linear equations F(u_ref. B. Ta_ref. Models of Agricultural Areas from Earth Observation Data”. kB-1= F(weighted with fc of a canopy. To) H is constrained between Hwet and Hdry Hdry= Rn-G Hwet=Rn-G-λEwet and λEwet obtained from Penman Monteith (meteorology!!) Λr = 1− 2. Stable and unstable situations MOS & BAS considered. a soil and an interaction function) Algorithms for upscaling ASL -> PBL and downscaling PBL-> ASL Uses Monin-Obukhov Similarity (MOS) for ASL Uses Bulk atmospheric Boundary Layer (ABL) Similarity (BAS) for PBL scaling Criteria for using MOS or BAS follows (Brutsaert.Adopted/distinctive SEBS concepts 1. E. Lima. H. Roughness for heat transfer is calculated instead of being a “fixed” value with respect to roughness for momentum 3. 13 March 2008 . 1999). Valid for unstable conditions. S. u*. Perú. Perú. E. B.Relative evaporation The relative evaporation is given as S. Lima. 13 March 2008 . Models of Agricultural Areas from Earth Observation Data”. Surface air potentials S. Perú. E. Lima. B. Models of Agricultural Areas from Earth Observation Data”. 13 March 2008 . 13 March 2008 . E.Normalized temperature difference versus albedo S. Lima. Models of Agricultural Areas from Earth Observation Data”. Perú. B. The scalar roughness height for heat transfer ( z 0 h = z 0 m / exp kB −1 ) The within-canopy wind speed profile extinction coefficient. 13 March 2008 . Lima. B. Perú.46 Re * 14 2 ) z0 m u* ⋅ ⋅ k u h h ( ) 2 −1 2 + kB fc + 2 fc fs s fs * Ct − ln[7. Models of Agricultural Areas from Earth Observation Data”. nec = kB −1 = kB −1 s C d ⋅ LAI 2u*2 u (h ) 2 kC d ( u* 4Ct 1 − e − nec u (h ) ( ) = 2. E.4] S. 13 March 2008 .Turbulent Heat Fluxes ⎡ ⎛ z − d0 ⎞ ⎛ z0 m ⎞⎤ ⎛ z − d0 ⎞ ⎟⎟ − Ψm ⎜ ⎟ + Ψm ⎜ ⎟⎥ ⎢ln⎜⎜ ⎝ L ⎠ ⎝ L ⎠⎦ ⎣ ⎝ z0 m ⎠ L = − ρ C p u *3θ v kgH G0 H Rn ⎡ ⎛ z − d0 H = ku * ρ C p (θ 0 − θ a )⎢ ln ⎜⎜ ⎣ ⎝ z0h ⎞ ⎛ z − d0 ⎞ ⎛ z0h ⎟⎟ − Ψh ⎜ ⎟ + Ψh ⎜ ⎝ L ⎠ ⎝ L ⎠ LE u* u= k ⎞⎤ ⎟⎥ ⎠⎦ −1 Wind. Lima. u . q ] ? S. thermal dynamic roughness) [z 0 m . humidity (aerodynamic roughness. B. z 0 h ] ? [Ta . air temperature.Energy Balance Residual Method . d 0 . Perú. Models of Agricultural Areas from Earth Observation Data”. E. Models of Agricultural Areas from Earth Observation Data”. E. No interaction after the process is initiated. calculation time depends on number of pixels in the map and. optional inputs and alternative or subrogate inputs to compensate mandatory's. 13 March 2008 . of course. All input is delivered in one interface. Mandatory value Mandatory map Mandatory Map or Modeled map Mandatory map or mandatory value Mandatory value: manual or modeled Surrogate value S. There are mandatory inputs. Require both maps and ground data. B. Perú. Lima.SEBS Interface Originally developed in Beam and converted to ILWIS last year. processor speed. B. PV →u*. Λr . G → Λ Λ. Zoh → Lwet. Rn24. Hwet. kB-1. G → λEwet λEwet.SEBS sequence SW↓. LAI. ro. H. Rn. To. E. Zoh RH. Rn. Zom. Ta. Rn. G → Hdry Based on PBL height and Reference height: MOS or BAS U. Rn → G Rn. L. H → Λr Hwet. Ta. Hwet Hdry. To. u*. εa → Rn Pv. G. Models of Agricultural Areas from Earth Observation Data”. 13 March 2008 . Rn. G → λEwet Λ. Perú. Lima. G24 → Edaily S. L. 13 March 2008 . Lima. u* Rn Rn Fc G AC: atmospherically corrected Rn: net radiation Fc: fractional canopy coverage G: soil heat flux Rn: net radiation Fc: fractional canopy coverage S. Models of Agricultural Areas from Earth Observation Data”. Surf.1 ± 0.SEBS Input: Mandatory maps Surface Temp. E.01 Used for: Rn G H. Emissivity Albedo NDVI Pre-processing: Units [K] AC Units [-] broadband Units [-] AC.01 ± 0. B. Perú. broadband Units [-] AC Precision: ± 0.01 ± 0. Perú. Models of Agricultural Areas from Earth Observation Data”. B.01 Used for: kB-1 G kB-1 Zom (attribute table) S. E. 13 March 2008 .1 ± 0. Lima.01 ± 0.SEBS Input: Mandatory or modeled maps LAI Equations! NDVI ⋅ (1 + NDVI ) 1 − NDVI Pv Land Use NDVI − NDVImin (NDVImax − NDVImin )2 Precision: ± 0. 5) = 0. Perú. Models of Agricultural Areas from Earth Observation Data”. Lima.5) τ = 0.0116 βa(5.5) Hβa0 = H1⋅ βa(0) Hβa5.5 ln( βa(0) / βa(5. 13 March 2008 .05 − H1⋅ βa(5.5) SW ↓= 1367 ⋅ eo ⋅ cos(SZA) ⋅ e − 1 ⋅τ cos( SZA ) S. E.0030765 βa(0) = H 1 = 5 .42 ⋅ Hβa0 exp(DEM / H1 + Hβa5.5 = 0. B.Mandatory value when modeled log(50) − β r (0 ) Vis βr (0) = 0. Lima. Models of Agricultural Areas from Earth Observation Data”. B.15 ) 2 S. Perú.15 ) 2 LW ↓= 5.OTHER equations in the program ε atm = 9. 13 March 2008 . E.678 ⋅ 10 −8 ⋅ ε atm ⋅ (Ta + 273.2 ⋅ 10 −6 ⋅ (Ta + 273. Lima. S. Perú.Outputs from SEBS as Maps in ILWIS Instantaneous actual evaporation Daily evaporation Soil heat flux Sensible heat flux at dry limit Sensible heat flux at wet limit Sensible heat flux Net radiation Latent heat flux Updates are possible after feedback. Models of Agricultural Areas from Earth Observation Data”. E. B. 13 March 2008 .