SUBROUTINE satang(XLAT,XLON,SUBLON,ANGZEN,ANGNDR) DATA TWOPI/6.28318/, R/6371./, H/35680./ DEGRAD=360./TWOPI ZLON=XLON IF(ZLON.LT.0.) ZLON=360.+ZLON ZSUBLN=SUBLON IF(ZSUBLN.LT.0.) ZSUBLN=360.+ZSUBLN DIFLON=ABS(ZLON-ZSUBLN)/DEGRAD DIFLAT=ABS(XLAT)/DEGRAD COSPSI=COS(DIFLON)*COS(DIFLAT) PSI=ACOS(COSPSI) SSQR=R*R + (R+H)*(R+H) - 2*R*(R+H)*COSPSI S=SQRT(SSQR) SINNDR=(R/S)*SIN(PSI) SINZEN=((R+H)/R)*SINNDR ANGZEN=ASIN(SINZEN)*DEGRAD ANGNDR=ASIN(SINNDR)*DEGRAD RETURN END