*IF DEF,A03_7A RAERO7A.2 C *****************************COPYRIGHT****************************** RAERO7A.3 C (c) CROWN COPYRIGHT 1997, METEOROLOGICAL OFFICE, All Rights Reserved. RAERO7A.4 C RAERO7A.5 C Use, duplication or disclosure of this code is subject to the RAERO7A.6 C restrictions as set forth in the contract. RAERO7A.7 C RAERO7A.8 C Meteorological Office RAERO7A.9 C London Road RAERO7A.10 C BRACKNELL RAERO7A.11 C Berkshire UK RAERO7A.12 C RG12 2SZ RAERO7A.13 C RAERO7A.14 C If no contract has been raised with this copy of the code, the use, RAERO7A.15 C duplication or disclosure of it is strictly prohibited. Permission RAERO7A.16 C to do so must first be obtained in writing from the Head of Numerical RAERO7A.17 C Modelling at the above address. RAERO7A.18 C ******************************COPYRIGHT****************************** RAERO7A.19 !********************************************************************** RAERO7A.20 ! Routine to calculate the aerodynamic resistance RAERO7A.21 ! RAERO7A.22 ! Written by Peter Cox (June 1997) RAERO7A.23 !********************************************************************** RAERO7A.24SUBROUTINE RAERO (LAND_FIELD,LAND_INDEX,P_FIELD 1RAERO7A.25 &, VEG_PTS,VEG_INDEX RAERO7A.26 &, RIB,WIND,Z0H,Z0M,Z1,RA) RAERO7A.27 RAERO7A.28 IMPLICIT NONE RAERO7A.29 RAERO7A.30 INTEGER RAERO7A.31 & LAND_FIELD ! IN Total number of land points. RAERO7A.32 &,LAND_INDEX(LAND_FIELD) ! IN Index of land points on the RAERO7A.33 ! ! P-grid. RAERO7A.34 &,P_FIELD ! IN Total number of P-gridpoints. RAERO7A.35 &,VEG_PTS ! IN Number of vegetated points. RAERO7A.36 &,VEG_INDEX(LAND_FIELD) ! IN Index of vegetated points RAERO7A.37 ! ! on the land grid. RAERO7A.38 &,I,J,L ! WORK Loop counters. RAERO7A.39 RAERO7A.40 REAL RAERO7A.41 & RIB(P_FIELD) ! IN Bulk Richardson number. RAERO7A.42 &,WIND(P_FIELD) ! IN Windspeed (m/s). RAERO7A.43 &,Z0H(LAND_FIELD) ! IN Roughness length for heat (m). RAERO7A.44 &,Z0M(LAND_FIELD) ! IN Roughness length for momentum (m) RAERO7A.45 &,Z1(P_FIELD) ! IN Reference level (m). RAERO7A.46 &,RA(LAND_FIELD) ! OUT Aerodynamic resistance (s/m). RAERO7A.47 &,BH ! WORK Stability coefficient. RAERO7A.48 &,CHN(LAND_FIELD) ! WORK Neutral drag coefficient. RAERO7A.49 &,FH(LAND_FIELD) ! WORK Stability factor. RAERO7A.50 &,ZETAH,ZETAM ! WORK Tempories in calculation of RAERO7A.51 ! ! CHN. RAERO7A.52 !----------------------------------------------------------------------- RAERO7A.53 ! Local parameters RAERO7A.54 !----------------------------------------------------------------------- RAERO7A.55 REAL RAERO7A.56 & AH,CZ ! Stability parameters. RAERO7A.57 &,KARMAN ! Von Karman's constant. RAERO7A.58 PARAMETER (AH = 10.0, CZ = 4.0, KARMAN = 0.4) RAERO7A.59 RAERO7A.60 !----------------------------------------------------------------------- RAERO7A.61 ! Calculate the neutral bulk tranfer coefficient. RAERO7A.62 !----------------------------------------------------------------------- RAERO7A.63 DO J=1,VEG_PTS RAERO7A.64 L = VEG_INDEX(J) RAERO7A.65 I = LAND_INDEX(L) RAERO7A.66 ZETAM = LOG((Z1(I) + Z0M(L)) / Z0M(L)) RAERO7A.67 ZETAH = LOG((Z1(I) + Z0M(L)) / Z0H(L)) RAERO7A.68 CHN(L) = (KARMAN * KARMAN) / (ZETAH * ZETAM) RAERO7A.69 ENDDO RAERO7A.70 RAERO7A.71 !----------------------------------------------------------------------- RAERO7A.72 ! Calculate the stability factor. RAERO7A.73 !----------------------------------------------------------------------- RAERO7A.74 DO J=1,VEG_PTS RAERO7A.75 L = VEG_INDEX(J) RAERO7A.76 I = LAND_INDEX(L) RAERO7A.77 BH = AH * CHN(L) * CZ * SQRT (Z1(I) / Z0H(L)) RAERO7A.78 IF (RIB(I) .GE. 0.0) THEN RAERO7A.79 FH(L) = 1.0 / (1 + AH * RIB(I)) RAERO7A.80 ELSE RAERO7A.81 FH(L) = 1 - AH * RIB(I) / (1 + BH * SQRT(-RIB(I))) RAERO7A.82 ENDIF RAERO7A.83 ENDDO RAERO7A.84 RAERO7A.85 !----------------------------------------------------------------------- RAERO7A.86 ! Calculate the aerodynamic resistance. RAERO7A.87 !----------------------------------------------------------------------- RAERO7A.88 DO J=1,VEG_PTS RAERO7A.89 L = VEG_INDEX(J) RAERO7A.90 I = LAND_INDEX(L) RAERO7A.91 RA(L) = 1.0 / (FH(L) * CHN(L) * WIND(I)) RAERO7A.92 ENDDO RAERO7A.93 RAERO7A.94 RETURN RAERO7A.95 END RAERO7A.96 *ENDIF RAERO7A.97