!-------------------------------------------------------------------------------------------------- ! DOXYGEN !> @brief COMPUTE THE SOLAR-EARTH DISTANCE !> @details CALCULATES THE SOLAR-EARTH DISTANCE ON EACH DAY FOR USE IN SHORT-WAVE RADIATION. !> @author ORIGINATOR - Q.ZHAO !> @date 96-07-23 \n !> @author LUCCI !> @date 18-03-20 \n !> @version V1.1.0 !> @details MODERNIZATION OF THE CODE, INCLUDING: !! * F77 TO F90/F95 !! * INDENTATION & UNIFORMIZATION CODE !! * REPLACEMENT OF COMMONS BLOCK FOR MODULES !! * DOCUMENTATION WITH DOXYGEN !! * OPENMP FUNCTIONALITY !< !> @param[out] R1 - THE NON-DIMENSIONAL DISTANCE BETWEEN SUN AND THE EARTH (LESS THAN 1.0 IN !! SUMMER AND LARGERTHAN 1.0 IN WINTER). !> @details Use Module: !! @arg @c CTLBLK !! @arg @c F77KINDS !> @details Driver: !! @arg @c INIT !> @details Calls: !-------------------------------------------------------------------------------------------------- SUBROUTINE SOLARD(R1) !-------------------------------------------------------------------------------------------------- ! SUBROUTINE SOLARD ! ! SUBPROGRAM: SOLARD - COMPUTE THE SOLAR-EARTH DISTANCE ! PROGRAMMER: Q.ZHAO ! ORG: W/NMC2 ! DATE: 96-07-23 ! ! ABSTRACT: ! SOLARD CALCULATES THE SOLAR-EARTH DISTANCE ON EACH DAY FOR USE IN SHORT-WAVE RADIATION. ! ! PROGRAM HISTORY LOG: ! 96-07-23 Q.ZHAO - ORIGINATOR ! 98-10-09 Q.ZHAO - CHANGED TO USE IW3JDN IN W3LIB TO CALCULATE JD. ! 18-01-15 LUCCI - MODERNIZATION OF THE CODE, INCLUDING: !> * F77 TO F90/F95 ! * INDENTATION & UNIFORMIZATION CODE ! * REPLACEMENT OF COMMONS BLOCK FOR MODULES ! * DOCUMENTATION WITH DOXYGEN ! * OPENMP FUNCTIONALITY ! ! INPUT ARGUMENT LIST: ! NONE ! ! OUTPUT ARGUMENT LIST: ! R1 - THE NON-DIMENSIONAL DISTANCE BETWEEN SUN AND THE EARTH (LESS THAN 1.0 IN SUMMER AND LARGER ! THAN 1.0 IN WINTER). ! ! INPUT/OUTPUT ARGUMENT LIST: ! NONE ! ! USE MODULES: CTLBLK ! F77KINDS ! ! DRIVER : INIT ! ! CALLS : ----- !-------------------------------------------------------------------------------------------------- USE CTLBLK USE F77KINDS ! IMPLICIT NONE ! REAL (KIND=R4) , PARAMETER :: PI = 3.1415926 REAL (KIND=R4) , PARAMETER :: PI2 = 2. * PI ! LOGICAL(KIND=L4) ::& & LEAP ! INTEGER(KIND=I4) , DIMENSION(12) ::& & NDM !------------------------ ! IMPLICIT NONE VARIABLES !------------------------ INTEGER(KIND=I4) ::& & ITER , JD , JDAY , JHR , JMNTH , JYR , JYR19 , JMN , JDOR1 , & & JDOR2 , IW3JDN ! REAL (KIND=R4) ::& & CCR , TPP , DAYINC , DAT , T , YEAR , EC , DATE , FJD , & & EM , E , EP , CR ! REAL (KIND=R4) , INTENT(OUT) ::& & R1 ! ! DATA JYR19 / 1900 / DATA JMN / 0 / DATA CCR /1.3E-6/ ! DATA NDM /0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334/ ! !------------------------------------------------------------ ! TPP = DAYS BETWEEN EPOCH AND PERIHELION PASSAGE OF 1900 ! JDOR1 = JD OF DECEMBER 30, 1899 AT 12 HOURS UT ! JDOR2 = JD OF EPOCH WHICH IS JANUARY 0, 1990 AT 12 HOURS UT !------------------------------------------------------------ DATA TPP / 1.55 / DATA JDOR1 /2415019/ DATA JDOR2 /2415020/ !-------------------------------------------------------------------------------------------------- ! COMPUTES JULIAN DAY AND FRACTION FROM YEAR, MONTH, DAY AND TIME UT ACCURATE ONLY BETWEEN MARCH 1, ! 1900 AND FEBRUARY 28, 2100 BASED ON JULIAN CALENDAR CORRECTED TO CORRESPOND TO GREGORIAN CALENDAR ! DURING THIS PERIOD !-------------------------------------------------------------------------------------------------- JYR = IDAT(3) JMNTH = IDAT(1) JDAY = IDAT(2) JHR = IHRST ! JD = IW3JDN(JYR, JMNTH, JDAY) ! IF (JHR >= 12) THEN JD = JD - 1 FJD = .5E0 + .041666667E0 * FLOAT(JHR ) + .00069444444E0 * FLOAT(JMN) ELSE FJD = .041666667E0 * FLOAT(JHR-12) + .00069444444E0 * FLOAT(JMN) END IF ! DAYINC = JHR / 24.0 JD = JD + FJD + DAYINC FJD = JD + FJD + DAYINC - JD !----------------------------------- ! CALCULATE THE SOLAR-EARTH DISTANCE !----------------------------------- DAT = FLOAT(JD - JDOR2) - TPP + FJD !---------------------------------------------- ! COMPUTES TIME IN JULIAN CENTURIES AFTER EPOCH !---------------------------------------------- T = FLOAT(JD - JDOR2) / 36525.E0 !------------------------------------------------------------------- ! COMPUTES LENGTH OF ANOMALISTIC AND TROPICAL YEARS (MINUS 365 DAYS) !------------------------------------------------------------------- YEAR = .25964134E0 + .304E-5 * T !------------------------------------ ! COMPUTES ORBIT ECCENTRICITY FROM T !------------------------------------ EC = .01675104E0 - (.418E-4 + .126E-6 * T) * T YEAR = YEAR + 365.E0 !------------------------------------------ ! DATE = DAYS SINCE LAST PERIHELION PASSAGE !------------------------------------------ DATE = MOD(DAT, YEAR) !---------------------------------------- ! SOLVE ORBIT EQUATIONS BY NEWTONS METHOD !---------------------------------------- EM = PI2 * DATE / YEAR E = 1.E0 ITER = 0 31 EP = E - (E - EC * SIN(E) - EM) / (1.E0 - EC * COS(E)) CR = ABS(E - EP) E = EP ITER = ITER + 1 ! IF (ITER > 10) GOTO 931 IF (CR > CCR) GOTO 31 ! 931 CONTINUE ! R1 = 1.E0 - EC * COS(E) ! ! WRITE(6,999) JYR, JMNTH, JDAY, JHR, R1 ! 999 FORMAT('SUN-EARTH DISTANCE CALCULATION FINISHED IN SOLARD'/'YEAR=',I5,' MONTH=',I3, & & ' DAY=',I3,' HOUR=',I3,' R1=',F9.4) !---------------- ! RETURN TO RADTN !---------------- RETURN ! END SUBROUTINE SOLARD