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For interpolation of data we assume that the averages for the periods representmeasurements occurring at the midpoints of the periods. A general interpolation formulabased on the t1 and t2 period identifiers from step (2) is:Dataimage= Data( Data − Data )∆t⎡⎢t⎣t 2 t1t +1 image(Local time)⎛− ⎜ t⎝1− FlagDST+ ∆tFlagperiod∆t⎞⎤− ⎟2⎥⎠⎦where;Datat1Datat2= the average value for the specific data parameter (i.e., wind or ETr) forthe t1 time period= the average value for the specific data parameter (i.e., wind or ETr) forthe t2 time periodExample:Using the weather data from section B-1.The Image Overpass Date&Time: 6/20/2000, 17:49 GMTLocation of weather station: In Mountain Time zone (time correction is -7)Weather Data: Given in section B-1 (Aberdeen, Idaho; based on DST)t image (Local Time) = 17:49 – 7:00 = 10:49 amFor this weather data DST was applied and the time identifier (label) for the weather datarepresented the endpoint of the data period (Flag DST = 1, Flag period = 0). ∆t = 1 hour.Therefore, t1 and t2 are calculated as:⎡(10 + 49 / 60)1 ⎤t 1 = int ⎢+ − 0 1 + 1 ==1 2 ⎥() int )⎣⎦[ 11.3] ( 1 + 1 12hourst 2 = 12 + 1 = 13hoursTherefore, the two weather data periods used to determine the wind speed and ETr at theimage time are 1200 and 1300 hours, Mountain Standard Time.Calculate the instantaneous wind speed at 10:49 AM (Mountain Standard Time) byapplying a linear interpolation using the reported time periods of 1200 and 1300 hours(Mountain Daylight Savings Time, MDT).60
The wind speed is 3.4 m/s for the 1200 period and 4.5 m/s for the 1300 period (seeweather data).The wind speed at 10:49 AM (i.e., image time) is calculated as:( 4.5 − 3.4)⎡⎛1 ⎞⎤Data image = 3. 4 + ( 10 49 / 60)12 1 1(0)= 3.75m / s1⎢ + − ⎜ − + − ⎟2⎥⎣⎝⎠⎦61
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SEBALSurface Energy Balance Algorit
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6. Tables for surface albedo comput
Page 5 and 6:
δ declination of the earth radians
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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 and 40: 1. If there is some cloud cover in
Page 41 and 42: • For all other formats (includin
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: 2. What time interval does the data
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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