The Two Source Energy Balance model using satellite, airborne and proximal remote sensing

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1 The using satellite, airborne and proximal remote sensing 7 years in a relationship Héctor Nieto Hector.nieto@irta.cat

Resistance Energy Balance Models (REBM) E R e n H G Physics based on an analogy to the Ohm s Law (Electricity) Heat transport is driven by a temperature gradient Some resistances oppose to the

2 Resistance Energy Balance Models (REBM) E R e n H G Physics based on an analogy to the Ohm s Law (Electricity) Heat transport is driven by a temperature gradient Some resistances oppose to the transport (Stomata, soil & air) TSEB inputs: Surface temperature Leaf Area Index H T r Meteo: S dn, T a, u and e a Albedo/spectral properties Fraction of LAI that is green Canopy height & width Python code available at 1

3 Retrieval of canopy (Tc) and soil temperatures (Ts) Components Tc and Ts obtained from: Dual angle LST Very High spatial res. LST...or Priestley-Taylor approach λe c = f g α PT Δ Δ + γ R n,c T rad θ f c θ T c f c θ T s 4 Τ 1 4 f c θ = 1 exp 0.5LAI cos θ 2 Menenti et al. (2008) Advances in Land Remote Sensing

4 Scale effects in TSEB DTD (MODIS, 1km) TSEB (Landsat, 30m) DTD+DisAlexi (MODIS+Landsat) Bias (W m -2 ) RMSE (W m -2 ) correlation Guzinski et al. (2014) Biogeosciences 3

5 TSEB and UAV data on barley Very high resolution of optical and TIR data (few cm) Good performance under overcast conditions Hoffman et al. (2016) HESS 4

6 TSEB-PT during senescence Δ λe c = f g α PT Δ + γ R n,c 5

7 Leaf Angle Distribution on TSEB Implementation of 4SAIL radiative transfer model: TSEB- 2ART with AATSR data 4SAIL accounts for LAD, emissivity & reflected longwave radiation 2 angle (with and without 4SAIL) vs. single angle f c θ = 1 exp 0.5LAI cos θ RMSE (W m -2 ) correlation 2ART 2A 1A 2ART 2A 1A Barley field Conifer plantation Grazed meadow

8 Leaf Angle Distribution on TSEB Implementation of 4SAIL radiative transfer model: TSEB- 2ART with AATSR data 4SAIL accounts for LAD, emissivity & reflected longwave radiation 2 angle (with and without 4SAIL) vs. single angle Modification of the extinction coefficient for canopy gap fraction Based on the Campbell ellipsoidal LIDF (χ) f c θ = 1 exp κ be χ, θ LAI RMSE (W m -2 ) correlation 2ART 2A 1A 2ART 2A 1A Barley field Conifer plantation Grazed meadow Python code will be available at 7

9 Pushing TSEB beyond its limits TSEB assumes homogeneus canopies, or at least randomly placed clumpled canopies Affects transmission of radiation through the canopy (e.g. fipar/fapar) Affects wind speed attenuation below the canopy uses an empirical factor for smooth surfaces in soil resistance formulation (Rs) assumes negligible heat advection and heat storage at the canopy only includes 2 layers van Gogh (1889) 8

Radiation Transmission at Clumped Canopies Simplified

Uses effective values of LAI Clumping index developed

10 Radiation Transmission at Clumped Canopies Simplified RTM for estimation of canopy and soil net radiation Uses effective values of LAI Clumping index developed for randomly placed stands Only dependent on zenith solar angle Ω(θ) What about row crops? Python code will be available at 9

11 Wind profile in row crops Python code will be available at 10

12 Turbulent heat transport at the soil layer r s f u s, z 0,s, L Variable LAI Variable fg Smooth soil Constant LAI Variable fg Smooth soil Kustas et al. (2016) Remote Sens. Env. Constant LAI Variable fg Rough soil Python code will be available at 11

13 Exploting high res. T rad for T c and T s Contextual algorithm Thermal sharpening Python code will be available at 12

Fixation of CO 2 for photosynthesis Energy advection Heat flux

14 The Energy Balance Net Radiation R n E H e G F p p A h W t Rate of energy storage Latent Heat Flux Evapotranspiration Sensible Heat Flux Fixation of CO 2 for photosynthesis Energy advection Heat flux leaving the layer: Soil heat flux No advection R ee H n G 0 With advection 13

15 Future steps Validation and assessment of TSEB transpiration Can transpiration estimates provide added value to irrigation management compared to ET and/or other methods? Application to orchards (UAB MSc project) Evaluation of TSEB g s for yield forecast TSEB is one of many ET models Evaluation of other models/approaches (w/ USDA, CESBIO, UCLM?) Ensemble modeling for uncertainty assessment (w/ USDA) What about three sources? vine+grass+soil (w/ USDA/Raimat) or a dehesa (w/ CSIC, IFAPA) Data assimilation of remote sensing into crop models/dss for yield forecast and irrigation management From instantaneous ET to daily estimates Weather forecast models, (w/ meteosim/meteocat?) Hydrological models, (w/ DHI?) 14

16 Future steps Retrieval of LAI, fpar/fipar, fg/c a+b using radiative transfer models, w/ CCHS-CSIC Use of cloud points/lidar in the retrieval (w/ UdL/Mariano Garcia) Parallel/efficient processing of RTM inversion (w/ Computer Science Dept./hired staff) Operational satellite daily estimates of ET and crop stress Fusion of Sentinel 2 (VNIR 10m), Landsat-8 (30m) and Sentinel 3 (TIR 1km). (w/ ESA) Temporal gapfilling, STARFM (w/ USDA and IFAPA) Potential of microwaves? (w/ CESBIO/IsardSat/RyC?) Automatic processing of imagery Download and preprocessing of Copernicus (Sentinel+3rd parties) satellite data (MODTRAN/libRadTran) Mosaicking, collocation and correction of airborne data (Photoscan/hired staff) Explore termal sharpening methods (UAB MSc project) Others 15

17 Gràcies! 16

18 Appendix Two Source Energy Balance Model Resistance Energy Balance Models (REBM) One-source vs. Two-source H T r Kustas & Anderson (2009) Agric. For. Meteo.,

19 Appendix Two Source Energy Balance Model Can we apply TSEB model with a single directional observation? Iterative process using Priestley and Tailor parameterization Assumes green vegetation transpires at a potential rate (well watered, α PT =1.26) First estimate of Hc and hence Tc Ts & Hs Iteration until realistic fluxes (H & LE > 0) Need to estimate fraction of green vegetation (f g ) H E C f g PT Rn, C H c Rn c E c x, c Tc Ta C p T s 4 T rad θ 4 f c θ T c 4 1 f c θ r 18

$Appendix Leaf Area Index and optical remote sensing Differential absorption/refraction in the optical spectrum.$

20 Appendix Leaf Area Index and optical remote sensing Differential absorption/refraction in the optical spectrum. Usually between red and near infrared Canopy structural variable: advantage of using multiangular information Single observation Multiangular observations 19

Estimation of Wavelet Based Spatially Enhanced Evapotranspiration Using Energy Balance Approach

Estimation of Wavelet Based Spatially Enhanced Evapotranspiration Using Energy Balance Approach Dr.Gowri 1 Dr.Thirumalaivasan 2 1 Associate Professor, Jerusalem College of Engineering, Department of Civil