1 SUBROUTINE geo_zenith_angle(i,j,RLAT,RLON,SLAT,SLON,ZA)
48 real*8 dtr/0.017453293 /
51 real*8 rtd /57.29577951 /
53 real*8 res /40589641.0 /
54 real*8 c1 /1826835337.0/
55 real*8 c2 /538527888.0 /
57 REAL RZS /1786245696.0/
60 INTEGER,
INTENT(IN):: I,J
61 REAL,
INTENT(IN):: SLON,RLAT,RLON,SLAT
64 REAL A,B,C,COSD,COSE,E,P,PP
71 a = (90.0 - rlat) * dtr
72 b = (90.0 - slat) * dtr
75 c = abs(rlon- 360. - slon) * dtr
77 c = abs(rlon - slon) * dtr
80 cosd = cos(a)*cos(b) + sin(a)*sin(b)*cos(c)
85 cose = (pp + res - rzs) / (2.*re*p)
86 cose=max(min(cose,1.),-1.)