New IR snow emissivity table: Nalli2.IRsnow.EmisCoeff.nc4

[chengdang]

Adding a new IR snow emissivity table provided by Nick Nalli: Nalli_TFIRsnow_EmisCoeff-v11.nc

This table contains updated IR snow emissivities, in comparison to the current optional table: Nalli.IRsnow.EmisCoeff.nc4

CRTM will keep both LUTs per user request for testing.

[chengdang]

Renaming the table follow CRTM conventions and adding CRTM/offline version/release numbers:

mv Nalli_TFIRsnow_EmisCoeff-v11.nc Nalli2.IRsnow.EmisCoeff.nc4
ncatted -O -h -a Release_Offline,global,a,c,"2." Nalli2.IRsnow.EmisCoeff.nc4
ncatted -O -h -a Version_Offline,global,a,c,"1.1" Nalli2.IRsnow.EmisCoeff.nc4
ncatted -O -h -a Version,global,m,i,2 Nalli2.IRsnow.EmisCoeff.nc4
ncatted -O -h -a Release,global,m,i,1 Nalli2.IRsnow.EmisCoeff.nc4

[chengdang]

Adding global attribute Classification_Name: ncatted -O -h -a Classification_Name,global,a,c,"Nalli" Nalli2.IRsnow.EmisCoeff.nc4

[chengdang]

Data content in this table:

netcdf Nalli2.IRsnow.EmisCoeff {
dimensions:
    n_Angles = 10 ;
    n_Frequencies = 119 ;
    n_Grain_Sizes = 15 ;
    n_Temperature = 5 ;
variables:
    double Angle(n_Angles) ;
        Angle:_FillValue = NaN ;
        Angle:long_name = "Angle" ;
        Angle:description = "Angle (Z) dimension values for emissivity data" ;
        Angle:units = "degrees from vertical" ;
    double Frequency(n_Frequencies) ;
        Frequency:_FillValue = NaN ;
        Frequency:long_name = "Frequency" ;
        Frequency:description = "Frequency (F) dimension values for emissivity data" ;
        Frequency:units = "inverse centimeters (cm^-1)" ;
    double Grain_Size(n_Grain_Sizes) ;
        Grain_Size:_FillValue = NaN ;
        Grain_Size:long_name = "Grain_Size" ;
        Grain_Size:description = "Snow grain size (R) dimension values for emissivity data" ;
        Grain_Size:units = "effective radius in microns (um)" ;
    double Temperature(n_Temperature) ;
        Temperature:_FillValue = NaN ;
        Temperature:long_name = "Temperature" ;
        Temperature:description = "Temperature (T) dimension values for emissivity data" ;
        Temperature:units = "Kelvins" ;
    double Emissivity(n_Temperature, n_Grain_Sizes, n_Frequencies, n_Angles) ;
        Emissivity:_FillValue = NaN ;
        Emissivity:long_name = "Emissivity" ;
        Emissivity:description = "Spectral water surface emissivity data" ;
        Emissivity:units = "N/A" ;

// global attributes:
        :Description = "Thermal-IR to Far-IR Snow Surface Emissivity Model" ;
        :Date = "26-Apr-2023" ;
        :Notes = "Hybrid Physical Model based Wiscombe & Warren (1980) (WW80) and a modified version of the Hori et al. (2013) semi-empirical model, with specular surface fractions extrapolated to 1 micron radius. This model shows good agreement versus published observations for the range of observed snow particle sizes." ;
        :Author = "N. R. Nalli, NOAA/NESDIS/STAR" ;
        :Tdep = "refind" ;
        :REF_IND = "Iwabuchi-Yang11" ;
        :ref_ind = -1. ;
        :Dimensions = "n_Temperature x n_Grain_Sizes x n_Frequencies x n_Angles" ;
        :Reference1 = "Wiscombe and Warren (1980), J. Atmos. Sci., 37(12), 2712-2733." ;
        :Reference2 = "Dozier and Warren (1982), Water Resources Res., 18(5), 1424-1434." ;
        :Reference3 = "Iwabuchi and Yang (2011), J. Quant. Spec. Rad. Trans., 112, 2520-2525." ;
        :Reference4 = "Hori et al. (2013), Appl. Optics, 52(30), 7243-7255" ;
        :History = "Version 1.1 LUT written to NetCDF file using SNOW_EMIS_TO_NETCDF v1.0" ;
        :Release_Offline = "2." ;
        :Version_Offline = "1.1" ;
        :Version = 2 ;
        :Release = 1 ;
        :Classification_Name = "Nalli" ;
}

Where Version = 2 denotes the data values, Release =1denotes the data structure and file formats, Classification_Name = "Nalli" specify which CRTM I/O modules should be called for reading/writing the data.

[chengdang]

This table is ready to use in CRTM v2.4.1 and CRTM v3 feature branch: https://github.com/JCSDA/CRTMv3/tree/feature/cd_v241_sfc_emis

This table is stored in google drive temporarily with restricted access: https://drive.google.com/file/d/1Lc2tYOfsLespmJJwXkB2tm1QlUvTvTEX/view?usp=share_link

Unit test on this table will be added once the CRTM V3 and V2.4.1 develop branch are bug free.