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Appendix 1Acquiring Header File InformationThe header file of the satellite image contains important information for <strong>SEBAL</strong> processing.The following information must be obtained from the header file:• The satellite overpass date and time• The latitude and longitude of the image• The sun elevation angle, β, at the overpass time (used in the “Flat” Model, only)• Gain and Bias levels for each band (applicable for Landsat 7 ETM+, only)There are three methods for obtaining the header file information depending on the satellitetype (Landsat 5TM or Landsat 7ETM+) and on the format used to store the image on thedistribution disk.Method A: Method A is the most straightforward method for acquiring header fileinformation. It is applicable for the following satellite types and data formats:• Landsat 5 TM, where the original image format is NLAPS• Landsat 7 ETM+, where the original image format is NLAPS or FASTFor the NLAPS format, explore the original image disk. Find and open the small file titled“NLAPS Correction Processing Report.” This file contains all the information neededincluding the gains and biases for Landsat 7. For band 6 of Landsat 7, the top row of thegain and bias section is for the low gain image and the second row is for the high gainimage. We recommend using the low gain image as explained in section 2 B of the maintext.For Landsat 7 – FAST format, explore the original image disk. Open the bottom two smallFST files. These contain the gains and biases for bands 1-7 with biases in the first columnand gains in the second column. The list with six entries is for bands 1-5 and 7. The list withtwo entries is for band 6 (low gain on top, high gain below). The satellite overpass time isnot included in the FAST header files and Method B must be used to acquire exact imagetime from the internet.Print the header file information for future reference.Method B: Method B is used to obtain header file information via the internet. It isapplicable for the following data formats and satellite types:• Original image format is NLAPS and satellite type is Landsat 5TM (if the header fileis missing)• Original image format is FAST and satellite type is Landsat 5TM (regardless theheader file availability)• Original image format is FAST and satellite type is Landsat 7ETM+ (only if headerfile is available)40
• For all other formats (including GeoTIFF) where the satellite type is Landsat 5 TM(regardless the header file availability)(1) First, go to the Earth Explorer web page: http://edcsns17.cr.usgs.gov/EarthExplorer/(2) Click “Enter as a guest”.(3) In the “Data Set Selection” box, select TM (Landsat 5) or ETM+ (Landsat 7) dependingon the image, and click “Continue”.(4) Define “Acquisition Date” and “Path Row Search”, and click the “search” button.(5) When the search is finished, select the appropriate image and click “Result”.41
Page 1 and 2: SEBALSurface Energy Balance Algorit
Page 3 and 4: 6. Tables for surface albedo comput
Page 5 and 6: δ declination of the earth radians
Page 7 and 8: INTRODUCTION1. BACKGROUNDLand manag
Page 9 and 10: THE THEORETICAL BASIS OF SEBAL1. OV
Page 11 and 12: The surface emissivity is the ratio
Page 13 and 14: • Reference evapotranspiration, E
Page 15 and 16: Figure 3. Flow Chart of the Net Sur
Page 17 and 18: 2. The reflectivity for each band (
Page 19 and 20: and ET are specified for the two ex
Page 21 and 22: To complete step 2, model F06_surfa
Page 23 and 24: D. Choosing the “Hot” and “Co
Page 25 and 26: irrigated crops near Kimberly, Idah
Page 27 and 28: where; u * is the friction velocity
Page 29 and 30: Weather stationu, z x, z om, u *H f
Page 31 and 32: Note: An alternative method used by
Page 33 and 34: where;⎛ 2 ⎞⎜1+ x(0.1m)Ψ = 2
Page 35 and 36: where; ET inst is the instantaneous
Page 37 and 38: Figure 6 shows an example of a dail
Page 39: 1. If there is some cloud cover in
Page 43 and 44: On the main page, select Type in Pa
Page 45 and 46: These values for z om can vary by r
Page 47 and 48: Appendix 3Reference Evapotranspirat
Page 49 and 50: and click on “Open”3. Provide t
Page 51 and 52: 5. Describe weather station and wea
Page 53 and 54: 8. Save the output file using a nam
Page 55 and 56: 4. Go to the Viewer tool and view t
Page 57 and 58: Appendix 5Time Issues Around Weathe
Page 59 and 60: 2. What time interval does the data
Page 61 and 62: The wind speed is 3.4 m/s for the 1
Page 63 and 64: Table 6.3. ESUN λ for Landsat 5 TM
Page 65 and 66: Table 6.6. Typical albedo values.Fr
Page 67 and 68: 4. Make a first guess for T cold by
Page 69 and 70: Fig.3. P40/R30, Landsat 7 ETM+ 4/8/
Page 71 and 72: Fig.5. P40/R30, Landsat 7 ETM+ 4/8/
Page 73 and 74: We open the image or subset image a
Page 75 and 76: Now, we look at the northwest area
Page 77 and 78: (2) The regional weather or soil co
Page 79 and 80: We conclude that this “heat islan
Page 81 and 82: Part 1: using the manual iteration
Page 83 and 84: Part 2: Using the automatic iterati
Page 85 and 86: Appendix 9SAVI and LAI for Southern
Page 87 and 88: equation for G. The following are e
Page 89 and 90: and for 24-hours:Gwater = 0.9 Rn -
Page 91 and 92:
The Stability of the AtmosphereAppe
Page 93 and 94:
Appendix 12The SEBAL Mountain Model
Page 95 and 96:
where; t is the standard clock time
Page 97:
N. Momentum Roughness LengthThe mom
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