include file: orb_cosz.h 1 C----------------------------------------------------------------------- C C csm_share/orb_cosz.h C C Statement function to return the cosine of the solar C zenith angle. Assumes 365.0 days/year. C C------------------ Code History --------------------------------------- C C Original Author: Erik Kluzek C Date: Dec/97 C C Version information: C C CVS: $Id: orb_cosz.h,v 1.3 1998/04/01 07:14:06 ccm Exp $ C CVS: $Source: /fs/cgd/csm/models/CVS.REPOS/shared/csm_share/Attic/orb_cosz.h,v $ C CVS: $Name: ccm3_6_brnchT_crm2_1_2 $ C C----------------------------------------------------------------------- C ------------- Parameters ---------------------------------- real orb_pi ! pi, mathematical constant parameter( orb_pi = 3.14159265358979323846) C ------------- Input Arguments ----------------------------- real orb_jday ! Julian calender day (1.xx to 365.xx) real orb_lat ! Centered latitude (radians) real orb_lon ! Centered longitude (radians) real orb_declin ! Solar declination (radians) C ------------- Output -------------------------------------- real orb_cosz ! Cosine of the solar zenith angle C ------------- Statement function -------------------------- orb_cosz( orb_jday, orb_lat, orb_lon, orb_declin ) = $ sin(orb_lat)*sin(orb_declin) - cos(orb_lat)*cos(orb_declin) $ *cos(orb_jday*2.0*orb_pi + orb_lon) C