Vaisala AWS330 User Manual
Page 285
Appendix B ______________________________________________________ Calculation Formulas
VAISALA ______________________________________________________________________ 283
Calculation of Zenith Angle e
ω
δ
δ
cos
cos
)
cos(
sin
)
(
arccos(sin
⋅
⋅
+
⋅
=
Lat
Lat
e
where
Lon =
Station
longitude
Lat =
Station
latitude
π
δ
180
))
2
sin(
000908
.
0
)
2
cos(
006758
.
0
sin
070257
.
0
cos
399912
.
0
006918
.
0
(
⋅
⋅
+
⋅
−
⋅
+
⋅
−
=
A
A
A
A
15
)
0
.
12
(
⋅
−
=
TST
ω
365
1
360
−
⋅
=
DN
A
60
EQ
LMT
TST
+
=
60
4
⋅
+
=
Lon
GMT
LMT
TS
CT
GMT
−
=
)
2
sin(
3619
.
9
)
2
cos(
3495
.
3
sin
3515
.
7
cos
4281
.
0
0172
.
0
A
A
A
A
EQ
⋅
−
⋅
−
⋅
−
⋅
+
=
where
δ
= Declination
(-24.0 ... 24.0 degrees)
ω
= Hour Angle (-180.0 ... 180.0 degrees)
TST
= True Solar Time (in decimals)
LMT
= Local Mean Time (in decimals)
GMT = Greenwich Mean Time (in decimals)
CT
= Civil Time (in decimals)
TS =
Time
Shift