1
2      SUBROUTINE URBCALC
3!***********************************************************************
4!             URBCALC Module of the AMS/EPA Regulatory Model - AERMOD
5!
6!        PURPOSE: Calculates Parameters for Urban Stable Boundary Layer
7!
8!        PROGRAMMER: Roger Brode, PES, Inc.
9!
10!        DATE:    June 11, 1996
11!
12!        MODIFIED:  Calculate an urban ustar by setting equivalence
13!                   between convective sigma-w based on urban wtar
14!                   and mechanical sigma-w based on urban ustar at
15!                   a height of 7 times the urban roughness length.
16!                   R.W. Brode, PES, Inc., - 06/10/02
17!
18!        MODIFIED:  To set the value for Z_iuo at 400m instead of
19!                   500m in calculation of ZIURB, based on observed data.
20!                   R.W. Brode, PES, Inc., - 04/08/02
21!
22!        INPUTS:  Meteorological Variables for One Hour
23!
24!        OUTPUTS: Urban Mixing Height, Heat Flux, and "Convective
25!                 Velocity Scale"
26!
27!        ASSUMPTIONS:  <none>
28!
29!        CALLED FROM:  METEXT
30!***********************************************************************
31
32!---- Variable declarations
33      USE MAIN1
34      IMPLICIT NONE
35      CHARACTER MODNAM*12
36      REAL :: DELTUR , URBHF , RHO , HT7Z0
37
38      SAVE
39
40!---- Variable initializations
41      MODNAM = 'URBCAL'                                                 !      0
42
43!     Compute Urban-Rural Temperature Difference (DELTRUR = 12.0)
44!RWB  DELTUR = DELTRUR * (0.1046 * ALOG(URBPOP/REFPOP) + 0.9983)
45!RWB  Use rounded values for parameters
46      DELTUR = DELTRUR*(0.1*ALOG(URBPOP/REFPOP)+1.0)
47
48!     Compute Urban Convective Mixing Height
49      ZIURB = 400.0*(URBPOP/REFPOP)**0.25
50
51!     Compute Urban Heat Flux, and recalculate Monin-Obukhov length
52      URBHF = 0.03*DELTUR*USTAR
53      RHO = 101325./(287.04*TA)
54
55!     Compute Urban WSTAR
56      URBWSTR = ((G/TA)*URBHF*ZIURB)**0.333333
57
58!     Compute Urban USTAR; first set height for equivalence between
59!     convective and mechanical sigma-w as 7 times the maximum of the
60!     rural and urban surface roughness length.
61      HT7Z0 = 7.*MAX(URBZ0,SFCZ0)
62      URBUSTR = MAX(USTAR,SQRT(1.6*(HT7Z0/ZIURB)**0.6667)               &
63     &          /(1.3*(1.-HT7Z0/MAX(ZIURB,ZIMECH))**0.5)*URBWSTR)
64
65!     Compute equivalent Monin-Obukhov length
66      URBOBULEN = -((TA*URBUSTR**3)/(0.4*G*URBHF))
67
68!     Save Rural values of USTAR and OBULEN
69      RURUSTR = USTAR
70      RUROBULEN = OBULEN
71
72      CONTINUE
73      END


HyperKWIC - Version 1.00DD executed at 20:00 on 1 Mar 2018 | Personal or Academic or Evaluation User | Free for Non-Commercial, Non-Government Use