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Last Post 14 Jun 2019 12:46 PM by  Jeffrey Snoddy
Surface Energy Balance Algorithm for Land (SEBAL) for Evapotranspiration calculations
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Jeffrey Snoddy



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14 Jun 2019 12:46 PM
    Jeffrey Snoddy
    University Of Southern California (USC)
    Spatial Science Department,, M.S.

    Table 5. Summary of equipment and software needs for Normalized Difference Vegetation Index (NDVI) equation

    Equipment/Software Source Application
    ENVI ENVI Visualization/Analysis/ Data Organization
    ArcMap ESRI Visualization/Analysis
    ArcCatalog ESRI Data Organization
    Sankey www.Sankeymatic.com
    Mode Flow Charts
    S3 Amazon Web Services Database Storage
    Slack Slack.com Team Posting
    USC Library Services MyUSC Research
    Google Scholar https://scholar.google.com Research

    Table 6 Download earth explorer Landsat Data Continuity Mission (LDCM) satellite imagery

    Step One Goto https://earthexplorer.usgs.gov/ for satellite data.
    Step Two Select location: MNWD – Centroid, Lat. 33.158269, Long. -117.268689
    Step Three Select date range
    Step Four Select data sets i.e. LDCM OLI/TIRS C1 Level-1
    Step Five Select additional criteria i.e. cloud cover
    Step Six Select results
    Step Seven Select area of interest for download
    Step Eight Download Level-1 GeoTIFF Data Product (967.1 MB)
    Step Nine Open “7 Zip”
    Step Ten Select *. Tar file
    Step Eleven Select “Open Inside”
    Step Twelve Extract data
    Step Thirteen Save to folder
    Step Fourteen Test data

    Table 7 Calculation of Reflectance for study area using multispectral calculations

    Step One Open ENVI
    Step Two File open
    Step Three Select Shapefile
    Step Four Select file dropdown
    Step Five Open as Optical Sensor
    Step Six Select “LANDSAT”
    Step Seven Geotiff with Metadata
    Step Eight Open MTL File


    Step Nine Place shapefile over MTL in the Layer Manager
    Step Ten Goto tool box
    Step Eleven Select “Radiometric Calibration”
    Step Twelve Select “Multispectral “Calibration (ensure spectral subset indicates 7 out of 7 bands)
    Step Thirteen Select “file selection” in the right pane
    Step Fourteen Select the shape file
    Step Fifteen Click “OK”
    Step Sixteen Select “Reflectance in the Radiometric calibration”
    Step Seventeen Save as Reflectance
    Step Eighteen Remove MTL from the Layer Manager

    Table 8 Calculation of Albedo from multispectral bands 1,2,3,4 and 5

    Step One Insert Band Math Expression = [((0.356*B1) + (0.130*B2) + (0.373*B3) + (0.085*B4) + (0.072*B5) -0.0018) / 1.016]
    Step Two Select Band 1 “Blue”
    Step Three Select Band 2 “Red”
    Step Four Select Band 3 “Infrared”
    Step Five Select Band 4 “Shortwave infrared 1”
    Step Six Select Band 5 “Shortwave infrared 2”

    Table 9 Calculation of NDVI from Near Infrared (NIR) and Red multispectral bands

    Step One Insert Band Math Expression = [(b1-b2)/(b1+b2)]
    Step Two Select “Toolbox”
    Step Three Select “Reflectance” file
    Step Four Select Band 1 “NIR”
    Step Five Select Band 2 “Red”

    Table 10 Resize data using pixel aggregation resampling methods

    Step One Select “Toolbox”
    Step Two Select “Resize Data”
    Step Three Select “Reflectance”
    Step Four Select “Spatial Subset” > (select map, 20 samples, 20 lines)
    Step Five Select “Red” & “Near Infrared”
    Step Six Select Layer Manager
    Step Seven Right click on resized data
    Step Eight Select “Quick Stats”
    Step Nine Copy the DN for band One, open Excel and paste band one data into new column. Repeat with band two
    Step Ten Highlight to select both columns and create chart/scatter plot
    Step Eleven Right click data line in chart
    Step Twelve Select “Add Trend Line”


    Step Thirteen Select “display equation on chart” and “display R-squared value on chart”
    Step Fourteen Copy the y intercept number on the chart
    Step Fifteen Click on the file name (The header information will appear on the right)
    Step Sixteen At the bottom click on "Spatial Subset" to subset all the bands in the image or "Spectral Subset" to choose one band to subset
    Step Seventeen "Spatial Subset" brings up another box for choosing the exact location of the subset
    Step Eighteen "Image" will bring up the image with a subset box that can be re-sized and moved around the image.


    Table 11 Calculation of Weighted Difference Vegetation Index (WDVI) from multispectral bands 3, 4 and the y intercept from the resampled data

    Step One Insert Band Math Expression = B3-1.0157*B4
    Step Two Add equation B3-1.2337*B4 (the 1.2337 number comes from the Y intercept copied from the chart)
    Step Three Select Band 3 “Red” from calculated reflectance
    Step Four Select Band 4 “NIR” from calculated reflectance

    Table 12 Calculation of the soil brightness correction L Value from NDVI and WDVI

    Step One Insert Band Math Expression = [(1-2*1.6-b11*b22)]
    Step Two Select Band 11 “NDVI”
    Step Three Select Band 22 “WDVI”

    Table 13 Calculation of Soil-adjusted Vegetation Index (SAVI) from bands 3,4, and the L value
    Step One Insert Band Math Expression = ((B4-B3) *(1+B33))/(B4+B3+B33)
    Step Two Select Band 3 “Red”
    Step Three Select Band 4 “NIR”
    Step Four Select Band 33 “L” value

    Table 14 Calculation of the Leaf Area Index (LAI) from the SAVI values

    Step One Insert Band Math Expression = [(11*(b44^3))]
    Step Two Select Band 44 “SAVI”

    Table 15 Calculation of surface emissivity from calculated LAI

    Step One Insert Band Math Expression = [.986+0.004*b11]
    Step Two Select Band 11 “LAI”

    Table 16 Calculation of Thermal Infrared (TIR) from LCDM multispectral bands 10 and 11

    Step One Select “Toolbox”
    Step Two Select “Radiometric Calibration”
    Step Three Select “Thermal Bands” (2 of 2 bands)
    Step Four Select “Spatial Subset”
    Step Five Select shapefile of study area
    Step Six In the radiometric Calibration box> keep “Radiance “selected

    Table 17 Calculation of the canopy resistance to vapor transit (Rc) from both Thermal Infrared (TIR) bands

    Step One Insert Band Math Expression = [(((B1-0)/1) - ((1-b6) *1))]
    Step Two Select Band 1 “TIR” (check that the bands are 2/2)
    Step Three Select Band 6 “Emissivity”

    Table 18 Calculation of Top of Atmospheric (TOA) spectral radiance from Band 10

    Step One Insert Band Math Expression = [((1201.14)/(alog(((b1*480.89)/b2)
    +1)))]
    Step Two Select Band 1 “Emissivity”
    Step Three Select Band 2 “Rc Band 10”

    Table 19 Calculation of Top of Atmospheric (TOA) spectral radiance from Band 11

    Step One Insert Band Math Expression = [((1321.08)/(alog(((b1*774.89)/b2)+1)))]
    Step Two Select Band 1 “Enb”
    Step Three Select Band 6 “Rc Band 11”

    Table 20 Conversion of TOA average temperatures from K to °C

    Step One Insert Band Math Expression = ((b10+b11)/2)
    Step Two Select Band 10 “LST B10”
    Step Three Select Band 11 “LST B11”

    Table 21 Conversion to °C from K by adding absolute zero

    Step One Insert Band Math Expression = [B1-273.15]
    Step Two Select Band 1 “Average Temperature”

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