RAMSES	Systems Ecology
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DEFINITION MODULE GlobIrrad;

  (*******************************************************************

    Module  GlobIrrad     (Version 1.0)

      Copyright (c) 1994-2006 by Dimitrios Gyalistras and ETH Zurich.

    Purpose   Compute global extraterrestrial irradiance
              on a plane parallel to the earth's surface
              for a given latitude and day of the year.

    Remarks   References:

              Lee, R. (1978). Forest microclimatology.
                 Columbia Univ. Press, New York etc.

              Kuye, A. & Jagtap, S.S. (1992). Analysis of
                solar radiation data for Prot Harcourt,
                Nigeria. Sol. Energy 49:2,p139-145.

              Bindi, M. & Miglietta, F. (1991). Estimating
                daily global radiation from air temperature
                and rainfall measurements. Clim.Res. 1: p117-124.

              Goudriaan, J. (1977). Crop micrometeorology:
                a simulation study. Simulation monographs,
                PUDOC, Wageningen.


    Programming

      o Design
        Dimitrios Gyalistras      15/08/1994

      o Implementation
        Dimitrios Gyalistras      15/08/1994


    ETH Zurich
    Systems Ecology
    CHN E 35.1
    Universitaetstrasse 16
    8092 Zurich
    SWITZERLAND

    URLs:
        <mailto:RAMSES@env.ethz.ch>
        <http://www.sysecol.ethz.ch>
        <http://www.sysecol.ethz.ch/SimSoftware/RAMSES>

        
    Last revision of definition:  23/09/2007  af

  *******************************************************************)


  PROCEDURE SolarConst(): REAL;                       (* in [W m^/2] = [J/m^2/s] *)
  PROCEDURE SetSolarConst( solarConst: REAL ):BOOLEAN;

  PROCEDURE Latitude(): REAL;                         (* in degrees [-90.0..90.0] *)
  PROCEDURE SetLatitude( latitude: REAL ):BOOLEAN;


 (*
    NOTE:
    The following conventions are used:
    day = 1 corresponds to Jan 1st, day = 365 to Dec 31st
    time = 0.0 corresponds to midnight, time = 12.0 to noon.
  *)



  PROCEDURE SinSolarAltitude( day: INTEGER; t: REAL ):REAL;
  (*
    Returns the sine of the solar altitude angle for a given
    day and timepoint t.
  *)

  PROCEDURE SunRiseTime( day: INTEGER ): REAL;
  (*
    Returns the time of sunrise for a given day.
    NOTE: SunSetTime(day) = 24.0 - SunRiseTime(day).
          Daylength(day)  = 24.0 - 2*SunRiseTime(day)
          SolarTimeOfSunrise(day) = SunRiseTime(day) - 12.0
          SolarTimeOfSunset(day)  = 12.0 - SunRiseTime(day)
          (solar time: noon = 0.0; see also module SunPath routine
          LocalTime to convert a solar time value to a local time)
  *)





  PROCEDURE EI( day: INTEGER; t: REAL ):REAL;            (* in [W/m^2] *)
  (*
    Returns the instantaneous Extraterrestrial Irradiation (EI)
    for a given day and timepoint t.
  *)


  PROCEDURE IEI( day: INTEGER; t1,t2: REAL ):REAL;       (* in [Wh/m^2] *)
  (*
    Returns the Integral of the Extraterrestrial Irradiation (IEI)
    over the time interval [t1..t2] for a given day.
  *)


  PROCEDURE DEI( day: INTEGER ):REAL;                    (* in [Wh/m^2] *)
  (*
    Returns the Daily integral of Extraterrestrial Irradiation (DEI)
    for a given day.
    Note that DEI(day) = IEI(day,0.0,24.0)/24 .
  *)


END GlobIrrad.