[an error occurred while processing this directive] Land Data Assimilation Schemes (LDAS): Parameters

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Land Surface Parameters

NLDAS Soil Illustrations and Data Sets


The soils data sets featured on this page were derived from 1km Penn State STATSGO and 5 minute ARS FAO data, and have 11 layers and 16 texture classes. These data sets will eventually be used in the NLDAS research effort, but the exact specifics of such use have yet to be worked out. All information on this page has been provided by Qingyun Duan of the NOAA Office of Hydrology, and all inquires concerning the data should be directed toward him.

NLDAS Soil Illustrations

First most predominant soil texture classes over 1/8th NLDAS domain. Classes 1 to 7 are most common over the domain, with classes 8 and higher sometimes located over the central areas. First Most Predominant Surface Soil Classes Over NLDAS Domain

Second most predominant soil texture classes over 1/8th NLDAS domain. Classes 1 to 7 are most common over the domain, with classes 8 and higher sometimes located over the central and southern areas. Many areas are blank as they have no 2nd most predominant soil class. Second Most Predominant Surface Soil Classes Over NLDAS Domain


NLDAS Soil Texture Data Sets (ASCII)

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Information on First Most Predominant Surface Soil Texture Classes:

The following soil texture file contains the first most predominant soil texture class of each soil layer. The files consist of 1 soil texture value per 1/8th degree grid box with gridpoint (1,1) located at the upper left of the NLDAS grid. The files can be read with the following statement: 


      read(10,40) ((isoil(i,j),i=1,464),j=1,224)
40    format(464i3))
Layer 1 Data (TXDM1_01.GRD) Layer 2 Data (TXDM1_02.GRD)

Layer 3 Data (TXDM1_03.GRD) Layer 4 Data (TXDM1_04.GRD)

Layer 5 Data (TXDM1_05.GRD) Layer 6 Data (TXDM1_06.GRD)

Layer 7 Data (TXDM1_07.GRD) Layer 8 Data (TXDM1_08.GRD)

Layer 9 Data (TXDM1_09.GRD) Layer 10 Data (TXDM1_10.GRD)

Layer 11 Data (TXDM1_11.GRD)

Information on First and Second Most Predominant Surface Soil Texture Classes:

The following 2 soil texture files indicate the percentage of each 1/8th degree surface layer grid box that is taken up by the first most predominant and second most predominant soil texture classes. The files consist of 1 percentage value per 1/8th degree grid box with gridpoint (1,1) located at the upper left of the NLDAS grid. The files can be read with the following statement: 


      read(10,40) ((pcnt(i,j),i=1,464),j=1,224)
40    format(464f5.0)
Percentage of First Most Predominant Soil Texture Class in Surface Layer (pcnts_1.grd)

Percentage of Second Most Predominant Soil Texture Class in Surface Layer (pcnts_2.grd)

Detailed Information on All 11 Soil Layers:

The following 11 soil texture files contain data in the following format:

Column 1 X Coordinate Index
Column 2 Y Coordinate Index
Column 3 Longitude
Column 4 Latitude
Columns 5-21 Number of Occurrences of Soil
Classes 1-16 in Each 1/8th Grid Box

They can be read with the following statement, with gridpoint (1,1) located at the lower left of the NLDAS grid: 


            read (20, 100) ix,iy,xlon,ylat,(iclass(j),j=1,16)
  100       format (2i4,1x,f9.4,f8.4,20i4)
Layer 1 Data (stex_tab.01) Layer 2 Data (stex_tab.02)

Layer 3 Data (stex_tab.03) Layer 4 Data (stex_tab.04)

Layer 5 Data (stex_tab.05) Layer 6 Data (stex_tab.06)

Layer 7 Data (stex_tab.07) Layer 8 Data (stex_tab.08)

Layer 9 Data (stex_tab.09) Layer 10 Data (stex_tab.10)

Layer 11 Data (stex_tab.11)


The following 11 soil texture files contain data in the following format:

Column 1 X Coordinate Index
Column 2 Y Coordinate Index
Column 3 Longitude
Column 4 Latitude
Columns 5 Number of Inland Water Points in Each 1/8th Degree Pixel
Columns 6 Number of Bedrock Points in Each 1/8th Degree Pixel
Columns 7 Number of Missing or Ocean Points in Each 1/8th Degree Pixel
Columns 8 Number of Soil Classifications
(Excluding Bedrock, Ocean and Missing Points) in each 1/8th Degree Pixel
Columns 9-10 The First Most Dominant Classification and the
Corresponding Number of Occurences in Each 1/8th Degree Pixel
Columns 11-12 The Second Most Dominant Classification and the
Corresponding Number of Occurences in Each 1/8th Degree Pixel

They can be read with the following statement, with gridpoint (1,1) located at the lower left of the NLDAS grid: 


            read (10, 200) ix,iy,xlon,ylat,nwat,nroc,nmis,ncl,
     +           (icl(j),mcl(j),j=ncl,1,-1)
  200       format(2i4,1x,f9.4,f8.4,20i4)
Layer 1 Data (SOILTEXT.01) Layer 2 Data (SOILTEXT.02)

Layer 3 Data (SOILTEXT.03) Layer 4 Data (SOILTEXT.04)

Layer 5 Data (SOILTEXT.05) Layer 6 Data (SOILTEXT.06)

Layer 7 Data (SOILTEXT.07) Layer 8 Data (SOILTEXT.08)

Layer 9 Data (SOILTEXT.09) Layer 10 Data (SOILTEXT.10)

Layer 11 Data (SOILTEXT.11)


NLDAS Soil Hydraulic Properties Data Set (ASCII)

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The following soil hydraulic property files contain data in the following format:

Column 1 X Coordinate Index
Column 2 Y Coordinate Index
Column 3 Longitude
Column 4 Latitude
Columns 5 Porosity (%)
Columns 6 Field Capacity (%)
Columns 7 Wilting Point (%)
Columns 8 B Parameter
Columns 9 Saturated Soil Matric Potential (in m of H2O)
Columns 10 Saturated Soil Hydraulic Conductivity (in m/s)

The files can be read with the following statement, with gridpoint (1,1) located at the lower left of the NLDAS grid: 


            read (20, 200) ic,ir,xlon,ylat,xporos,xfldcp,xwltpt,
     x                     xb,xpsi50,xks50
  200       format(2i4,1x,f9.4,f8.4,5f9.3,e11.3)
Soil hydraulic properties data set based on Cosby's numbers except Ksat, which is based on Rawls' work.
Layer 1 Data (COS_RAWL.01) Layer 2 Data (COS_RAWL.02)

Layer 3 Data (COS_RAWL.03) Layer 4 Data (COS_RAWL.04)

Layer 5 Data (COS_RAWL.05) Layer 6 Data (COS_RAWL.06)

Layer 7 Data (COS_RAWL.07) Layer 8 Data (COS_RAWL.08)

Layer 9 Data (COS_RAWL.09) Layer 10 Data (COS_RAWL.10)

Layer 11 Data (COS_RAWL.11)

Soil hydraulic properties data set based on Clapp et al (1978, WRR)
Layer 1 Data (HYD_CLAP.01) Layer 2 Data (HYD_CLAP.02)

Layer 3 Data (HYD_CLAP.03) Layer 4 Data (HYD_CLAP.04)

Layer 5 Data (HYD_CLAP.05) Layer 6 Data (HYD_CLAP.06)

Layer 7 Data (HYD_CLAP.07) Layer 8 Data (HYD_CLAP.08)

Layer 9 Data (HYD_CLAP.09) Layer 10 Data (HYD_CLAP.10)

Layer 11 Data (HYD_CLAP.11)

Soil hydraulic properties data set based on Cosby et al. (1984, WRR)
Layer 1 Data (HYD_COSB.01) Layer 2 Data (HYD_COSB.02)

Layer 3 Data (HYD_COSB.03) Layer 4 Data (HYD_COSB.04)

Layer 5 Data (HYD_COSB.05) Layer 6 Data (HYD_COSB.06)

Layer 7 Data (HYD_COSB.07) Layer 8 Data (HYD_COSB.08)

Layer 9 Data (HYD_COSB.09) Layer 10 Data (HYD_COSB.10)

Layer 11 Data (HYD_COSB.11)

Soil hydraulic properties data set based on Rawls et al. (1991, Advances in Soil Science)
Layer 1 Data (HYD_RAWL.01) Layer 2 Data (HYD_RAWL.02)

Layer 3 Data (HYD_RAWL.03) Layer 4 Data (HYD_RAWL.04)

Layer 5 Data (HYD_RAWL.05) Layer 6 Data (HYD_RAWL.06)

Layer 7 Data (HYD_RAWL.07) Layer 8 Data (HYD_RAWL.08)

Layer 9 Data (HYD_RAWL.09) Layer 10 Data (HYD_RAWL.10)

Layer 11 Data (HYD_RAWL.11)

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Maintained and Updated at NOAA/NCEP/EMC		 Kenneth Mitchell: Kenneth.Mitchell@noaa.gov 
Youlong Xia: Youlong.Xia@noaa.gov		 NCEP webpage