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.

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