# Appendix A: Bird Clear Sky Model in Excel

Excel® Column A holds user inputs for Bird clear sky model in rows 6 to 29. Note the cell references rely on the exact structure of rows and columns shown. User values are entered in shaded cells. Bold text are labels for values to be entered in cell below label.

TABLE A.1

Bird Clear Sky Input Parameters

Row Number Column A, Label, Value, or Function 1 2

 3 4 5 N/A 6 USER 7 INPUTS 8 Latitude 9 User Value (+N, – S) 10 Longitude 11 User Value (+E, – W) 12 Time Zone 13 User Value (-W, +E) 14 Station Pressure mB 15 User Value 16 Ozone atm-cm 17 User Value (0.0-0.35) 18 Water Vapor H2O atm-cm 19 User Value (0.0-6.0) 20 Aerosol Optical Depth (AOD) @ 500 nm 21 User Value (0.0-0.4) 22 AOD @ 380 nm 23 User value (~1.5 x AOD @ 500 nm) 24 Taua (total AOD) 25 = 0.2758*\$A\$23+0.35*\$A\$21 26 Asymmetry Factor Ba 27 0.85 28 Ground Albedo (0.0 to 1.0) 29 0.2

TABLE A.2

Values and Functions to Be Entered in Row 3, from Columns B to V

 Column Row 1 Row 2 Rows 3-8762 B DOY 1 to 365 C HR 0 to 23 D Solar Position ETR = 1367*(1.00011+0.034221*COS(6.28318*(B3-1)/365) +0.00128*SIN(6.28318*(B3-1)/365)+0.000719 *COS(2*(6.28318*(B3-1)/365))+0.000077 *SIN(2*(6.28318*(B3-1)/365))) E Dangle = 6.283185*(B3-1)/365 F DEC = (0.006918-0.399912*COS(E3)+0.070257*SIN(E3) -0.006758*COS(2*E3)+0.000907*SIN(2*E3) -0.002697*COS(3*E3)+0.00148*SIN(3*E3)) *(180/3.14159) G EQT = (0.000075+0.001868*COS(E3)-0.032077*SIN(E3) -0.014615*COS(2*E3)-0.040849*SIN(2*E3))*(229.18) H Hour Angle = 15*((C3-0.5)-\$A\$13-12)+\$A\$11+G3/4 I Zenith Angle = ACOS(COS(F3/(180/3.14159))*COS(\$A\$9/(180/3.14159)) *COS(H3/(180/3.14159))+SIN(F3/(180/3.14159)) *SIN(\$A\$9/(180/3.14159)))*(180/3.14159) J Air Mass = IF(I3<89,1/(COS(I3/(180/3.14159)) +0.15/(93.885-I3)A1.25),0) K Transmittances T Rayleigh = IF(J3>0,EXP(-0.0903*(\$A\$15/1013)A0.84 *(1+\$A\$15/1013-(\$A\$15/1013)A1.01)),0) L T Ozone = IF(J3>0,1-0.1611*(\$A\$17*J3)*(1+139.48*(\$A\$17*J3))a -0.3034-0.002715*(\$A\$17*J3)/(1+0.044*(\$A\$17*J3) +0.0003*(\$A\$17*J3)A2),0) M T Gases = IF(J3>0,EXP(-0.0127*(J3*\$A\$15/1013)A0.26),0) N T Water = IF(J3>0,1-2.4959*J3*\$A\$19/((1+79.034*\$A\$19*J3) A0.6828+6.385*\$A\$19*J3),0) O T Aerosol = IF(J3>0,EXP(-(\$A\$25A0.873) *(1+\$A\$25-\$A\$25A0.7088)*J3A0.918),0) P TAA = IF(J3>0,1-0.1*(1-J3+J3A1.06)*(1-O3),0) Q Intermediate Results Rs = IF(J3>0,0.0685+(1-\$A\$27)*(1-O3/P3),0) R Id = IF(J3>0,0.9662*D3*O3*N3*M3*L3*K3,0) S IdnH = IF(I3<90,R3*COS(I3/(180/3.14159)),0) T Ias = IF(J3>0,D3*COS(I3/(180/3.14159))*0.79*L3*M3*N3*P3 *(0.5*(1-K3)+\$A\$27*(1-(O3/P3))/(1-J3+(J3)A1.02)),0) U GH = IF(J3>0,(S3+T3)/(1-\$A\$29*Q3),0) V Decimal Time = B3+(C3-0.5)/24 W MODEL RESULT (W/M2) Direct Beam = R3 X Direct Hz = S3 Y Global Hz = U3 Z Diffuse Hz = Y3-X3 Note: Text in columns 2 and 3 are simply labels to be entered into designated cell row/column location. Column 3 contains functions with references to row 3 cell contents, to be copied to the rows following.

Updated: August 22, 2015 — 1:24 am