Wrong values of PURB (percentage of urban area) in MCIP

MCIP
1

Hi all,

When I compared my CCTM output with the observation, I find the O3 value is much higher than the observation data. I searched the previous discussion https://www.cmascenter.org/cmaq/documentation/4.6/ADVECTION_DIFFUSION.txt . From the .txt, I guess there might be some mistakes with the Kzmin setting. I checked my GRIDCRO2D file and found the values of PURB are either -9.999*e+36 or 0.

I also found the discussion about the PURB MCIP cannot generate PURB (percentage of urban area) . Compared with the discussion, the LANDUSEF values in my geo_em.d01.nc file are between 0 and 1, and I did use the correct geo_em.d01.nc in the mcip script.

My question is that are the values of PURB correct? If not, how can I correct it? Thanks in advance!

Best,
Xiao

2

FWIW, the “-9.999e36” is “missing” (I/O API BADVAL3).

For the record, since REAL arithmetic has inherent round-off problems, the standard test that you may see in the code for missing is

`X < AMISS3 (== -9.0E36)`

Carlie J. Coats, Jr., Ph.D. cjcoats@email.unc.edu
Senior Software Engineer I/O API Author/Maintainer
Center for Environmental Modeling for Policy Development,
UNC Institute for the Environment www.ie.unc.edu
100 Europa Dr., Suite 490 Rm 4051 / Campus Box 1105 919.843.5951
Chapel Hill, NC 27599-1105 Fax 919.966.9920
c

3

Hi Carlie,

Thanks a lot! Do you have any idea how I can get a valid value for PURB?

4

I don’t know how MCIP does it, but when I’ve needed it, I’ve used the NLCD land cover as a starting point. (t’s on a 30meter-resolution Albers-projection grid), and when doing land surface modeling, I’ve taken that and averaged it over my modeling grid to get land cover fractions (much more accurate than going through some intermediate grid, but also more compute-intensive).

– Carlie

5

Hi Carlie,

Thank you for the information! I will have a try.

6

@xiaofen –

As @cjcoats pointed out, there is something wrong with your PURB values. PURB is the “percentage of urban area (based on land coverage)”, so the values should range between 0 and 100. The values in PURB are not going to be straight conversions of the fractions of urban area in the cell, so please proceed carefully if you want to do this independently.

Are you sure that you correctly added your geo_em.d01.nc file into your MCIP run? Please check your MCIP log file to see if you can find any additional information.

Tanya

8

Hi Tanya,

Sorry for the very late reply. I have looked into my MCIP log file. It seems no error or warning. The LANDUSEF has been read from geo_em.d01.nc file, while PURB is still missing. Here is part of the log file.

                USER OPTIONS AND GRID DEFINITIONS

Output start date = 2018-12-30-00:00:00.0000
Output end date = 2018-12-31-00:00:00.0000
Output interval = 60 minutes

LPV = 0: Will not calculate and output 3D potential vorticity
LWOUT = 0: Will not output vertical velocity from the met model
LUVCOUT = 1: Will output u- and v-component winds on C grid
LSAT = 0: Will not use satellite adjustment of clouds for photolysis

LAI was found in the meteorology input file

FRACTIONAL LAND USE was found in the meteorology input file
FRACTIONAL LAND USE will be read from the GEO file

MONIN-OBUKHOV LENGTH was NOT found in the meteorology input file

MONIN-OBUKHOV LENGTH will NOT be recomputed by MCIP (Only for WRF-ACM2)

AERODYNAMIC AND STOMATAL RESISTANCE was NOT found in the meteorology input file

2-m TEMPERATURE was found in the meteorology input file

2-m MIXING RATIO was NOT found in the meteorology input file

VEGETATION FRACTION was found in the meteorology input file

10-m WIND was found in the meteorology input file

CANOPY WETNESS was found in the meteorology input file

ROUGHNESS LENGTH was NOT found in the meteorology input file

SOIL MOISTURE, TEMPERATURE, AND TYPE was found in the meteorology input file
SOIL MOISTURE, TEMPERATURE, AND TYPE will be in the output file

TURBULENT KINETIC ENERGY was NOT found in the meteorology input file

URBAN CANOPY MODEL (WRF ONLY) was NOT used in the meteorology model

3D RESOLVED CLOUD FRACTION was found in the meteorology input file

Met domain dimensions (col, row, lay): 101 101 39
MCIP X domain dimensions (col, row, lay): 100 100 39
Output domain dimensions (col, row, lay): 98 98 39

Output grid resolution: 22.000000000000000 km
Window domain origin on met domain (col,row): 1 , 1
Window domain far corner on met domain (col,row): 101 , 101

Cells and points for diagnostic prints
LPRT_COL LPRT_ROW 49 49
LPRT_XCOL LPRT_XROW 50 50
LPRT_METX LPRT_METY 50 50

IOAPI header variables:
GDTYP3D 2
GDNAM3D Grid-Wuhan20
P_ALP3D 30.000
P_BET3D 60.000
P_GAM3D 112.000
XCENT3D 112.000
YCENT3D 30.000
XORIG3D -789000.000
YORIG3D -1072500.000
XCELL3D 22000.000
YCELL3D 22000.000
VGTYP3D 7
VGTOP3D 5000.000

VGLVS3D 1.00000 0.99300 0.98300 0.97000 0.95400 0.93400
0.90900 0.88000 0.84681 0.81362 0.78043 0.74723
0.68692 0.63036 0.57738 0.52778 0.48138 0.43801
0.39751 0.35973 0.32451 0.29171 0.26119 0.23283
0.20651 0.18210 0.15949 0.13859 0.11927 0.10174
0.08599 0.07185 0.05915 0.04775 0.03751 0.02831
0.02005 0.01264 0.00598 0.00000

GRIDOUT: Printing sample cells in output grid

 LAT       29.9048  DEGREES         
 LON      114.8817  DEGREES         

MSFX2 1.0008 (M/M)**2
HT 158.5387 M
DLUSE 5.0000 CATEGORY
LWMASK 1.0000 CATEGORY
PURB ************ PERCENT
LUFRAC_01 0.0000 FRACTION
LUFRAC_02 0.0000 FRACTION
LUFRAC_03 0.0000 FRACTION
LUFRAC_04 0.0015 FRACTION
LUFRAC_05 0.3898 FRACTION
LUFRAC_06 0.0000 FRACTION
LUFRAC_07 0.0000 FRACTION
LUFRAC_08 0.2450 FRACTION
LUFRAC_09 0.0062 FRACTION
LUFRAC_10 0.0015 FRACTION
LUFRAC_11 0.0000 FRACTION
LUFRAC_12 0.3482 FRACTION
LUFRAC_13 0.0000 FRACTION
LUFRAC_14 0.0000 FRACTION
LUFRAC_15 0.0000 FRACTION
LUFRAC_16 0.0000 FRACTION
LUFRAC_17 0.0077 FRACTION
LUFRAC_18 0.0000 FRACTION
LUFRAC_19 0.0000 FRACTION
LUFRAC_20 0.0000 FRACTION
LUFRAC_21 0.0077 FRACTION
LATD 29.8094 DEGREES
LOND 114.7638 DEGREES
MSFD2 1.0017 (M/M)**2
LATU 29.9083 DEGREES
LONU 114.7677 DEGREES
MSFU2 1.0008 (M/M)**2
LATV 29.8060 DEGREES
LONV 114.8776 DEGREES
MSFV2 1.0017 (M/M)**2

Thanks a lot for your help!