Add read-in capability for urban 2d fraction

[cenlinhe]

Originally, there is no input capability for HRLDAS to read in FRC_URB2D variable. This PR adds this capability to read in FRC_URB2D directly from hrldas_setup file along with other static 2D maps. If no FRC_URB2D variable is provided in hrldas_setup file, the model will use the values from URBPARM.TBL table.

[tslin2]

These code changes look great to me. As 2D urban fraction data cab be obtained from geo_em files in WPS.

However, there are other urban parameters from NUDAPT that is generated by WPS and use in WRF-Urban in grid cell where NUDAPT data is available (HGT_URB2D >0). If in the grid cell that NUDAPT is not available, it used the parameters from specified table.

Such parameters include as follows (bracket is the name used in wrf input files)

LP_URB2D (BUILD_AREA_FRACTION): BUILDING PLAN AREA DENSITY
HI_URB2D (HEIGHT_HISTOGRAMS): DISTRIBUTION OF BUILDING HEIGHTS
LB_URB2D (BUILD_SURF_RATIO): BUILDING SURFACE AREA TO PLAN AREA RATIO
HGT_URB2D (BUILD_HEIGHT): AVERAGE BUILDING HEIGHT WEIGHTED BY BUILDING PLAN AREA
MH_URB2D (MH_URB2D): Mean Building Height
STDH_URB2D (STDH_URB2D): Standard Deviation of Building Height
LF_URB2D (LF_URB2D): Frontal Area Index

These parameters can obtain from wrf input file but not directly from wps files.

For example, in SLUCM, if mean building height (MH_URB) from NUDAPT is larger than zero, NUDAPT parameters is used.

Do we need to include these 2D NUDAPT parameters as well?

Thanks.

[cenlinhe]

@tslin2 Yes, you are right. However, I do not have time right now to include all those urban parameters, so I create this urban fraction capability first and later we could add the other urban parameters based on this capability in a later PR.

[cenlinhe]

@CharlesZheZhang Can you take a look at this PR and approve it if there is no error?