Data sets have been produced at several
resolutions:
| Resolution | Name | Ice-Free Land Points | Global Gaussian Grid Dimensions | |
| Longitude | Latitude | |||
| 3.75° | t31 | 1034 | 96 | 48 |
| 2.8125° | t42 | 1811 | 128 | 64 |
| 2.8°x1.8° | r40 | 2902 | 128 | 102 |
| 1.875° | t63 | 4106 | 192 | 96 |
There are four types of data sets:
| Type | Time Interval | GDS Name | |
| Near Surface Meteorology | Gridded; Means, Totals | 6-Hour | <res>_<var name>
(see table below) |
| Land Surface Parameters | Gridded; Fixed | Once (non-varying) | <res>_fixed |
| Land Surface Means | Gridded; Means | Monthly | <res>_mean |
| Land Surface Snapshots | Gridded; Instantaneous Values | Monthly | <res>_snap |
The data sets are available currently on the GrADS/DODS server (GDS) at COLA. The directory listing for the GDS is: http://cola8.iges.org:9090/dods/. Look for GDS data set names listed above. The "info", "dds", and "das" links provide additional metadata.
To access the data, you need a DODS-enabled
analysis tool (client) such as GrADS version 1.8. This is currently
available for SunOS and Linux (redhat
7), with betas available for other platforms. (See the GrADS downloads
page at http://www.iges.org/grads/downloads.html.)
If your platform is not listed, please contact Jennifer
Adams about a build for your platform.
Once you get GrADS 1.8 running, you can simply open the data sets with the following commands:
ga-> sdfopen http://cola8.iges.org:9090/dods/lba_fixed
ga-> sdfopen http://cola8.iges.org:9090/dods/lba_mean
ga-> sdfopen http://cola8.iges.org:9090/dods/lba_point
ga-> sdfopen http://cola8.iges.org:9090/dods/lba_snap
...etc.
Then you treat the data as you would any
other local data set. An additional benefit of the GDS is that it allows
you
to do some analysis on the server side,
which can significantly speed up your interaction with the data. Using
the analysis capabilities of the GDS is
fairly simple if you are already familiar with GrADS syntax. Please consult
the
GDS web page for more information about
this: http://www.iges.org/grads/gds.
Look under the headings "How
do I access data distributed by the GDS?"
and "How do I do analysis operations on GDS data sets?" The analysis
capability can also be used for accessing
small subsets of the entire data set.
| Variable | Name | Units | Source(s) |
| Air temperature (2m AGL) | air | K | NCEP/NCAR reanalysis; Webber and Willmott; CAMS |
| Specific humidity (2m AGL) | shum | kg kg-1 | NCEP/NCAR reanalysis adjusted for consistency with air temperature |
| Wind speed (10m AGL) | uwnd | m s-1 | NCEP/NCAR reanalysis |
| Surface pressure | pres | pa | NCEP/NCAR reanalysis |
| Downward shortwave radiation | dswrf | W m-2 | NCEP/NCAR reanalysis, ISCCP/ISLSCP |
| Downward longwave radiation | dlwrf | W m-2 | NCEP/NCAR reanalysis, ISCCP/ISLSCP |
| Total precipitation | prate | kg m-2 s-1 | NCEP/NCAR reanalysis, Webber and Willmott; CMAP |
| Convective component of precipitation | cprat | kg m-2 s-1 | NCEP/NCAR reanalysis adjusted for consistency with total precipitation |
| Variable | Name | Units | Description |
| Vegetation type | v | - | Based on types from ISLSCP I-1 CD-ROM (see Table below) |
| Soil type | s | - | Based on classes from ISLSCP I-1 CD-ROM (see Table below) |
| Depth of surface soil layer | d1 | m | 5 cm globally |
| Depth of root layer | d2 | m | Function of vegetation type, total soil depth |
| Depth of recharge layer | d3 | m | Function of total soil depth from ISLSCP I-1 CD-ROM |
| Wilting point of surface + root layers | wp1 | m | Function of soil type and vegetation type |
| Wilting point of total soil column | wp2 | m | Function of soil type and vegetation type |
| Field capacity of surface + root layers | fc1 | m | Function of soil type |
| Field capacity of total soil column | fc2 | m | Function of soil type |
| Total capacity of surface + root layers | cap1 | m | Function of soil porosity |
| Total capacity of total soil column | cap2 | m | Function of soil porosity |
| Type | Definition | Seasonal Cycle |
| 1 | Broadleaf evergreen trees | No |
| 2 | Broadleaf deciduous trees | Yes |
| 3 | Broadleaf and needle leaf trees | Yes |
| 4 | Needle leaf evergreen trees | Yes |
| 5 | Needle leaf deciduous trees | Yes |
| 6 | Broadleaf trees with groundcover | Yes |
| 7 | Groundcover only | Yes |
| 8 | Not used | |
| 9 | Broadleaf shrubs with bare soil | Yes |
| 10 | Broadleaf shrubs with ground cover (Tundra) | Yes |
| 11 | Bare soil | No |
| 12 | Winter wheat and broadleaf deciduous trees | Yes |
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(m) |
(m/s) |
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| Variable | Name | Units |
| Soil moisture in the surface layer | w1 | mm |
| Soil moisture in the surface and root layers | w2 | mm |
| Soil moisture in the total soil column | w3 | mm |
| Soil wetness index of the surface layer | wi1 | -- |
| Soil wetness index of the surface and root layers | wi2 | -- |
| Surface snow (liquid water equivalent) | snow | mm |
| Effective skin temperature | skin | K |
| Precipitation rate | ppl | mm day-1 |
| Surface runoff rate | exc | mm day-1 |
| Total runoff rate | roff | mm day-1 |
| Snowmelt rate | melt | mm day-1 |
| Transpiration rate | trnsp | mm day-1 |
| Bare soil evaporation rate | sevap | mm day-1 |
| Direct snow evaporation rate | snev | mm day-1 |
| Interception loss | intrc | mm day-1 |
| Total evapotranspiration rate | ett | mm day-1 |
| Downward shortwave radiation at the surface | swd | W m-2 |
| Downward longwave radiation at the surface | lwd | W m-2 |
| Upward shortwave radiation at the surface | swu | W m-2 |
| Upward longwave radiation at the surface | lwu | W m-2 |
| Sensible heat flux | shf | W m-2 |
| Latent heat flux | lhf | W m-2 |
| Ground heat flux | ghf | W m-2 |
| Variable | Name | Units |
| Soil moisture in the surface layer | sm1 | mm |
| Soil moisture in the surface and root layers | sm2 | mm |
| Soil moisture in the total soil column | sm3 | mm |
| Soil wetness in the surface layer | sw1 | -- |
| Soil wetness in the surface and root layers | sw2 | -- |
| Temperature of vegetation canopy | tc | K |
| Effective skin temperature | tskin | K |
| Temperature of surface layer | t1 | K |
| Temperature of root layer | t2 | K |
| Temperature of recharge layer | t3 | K |
| Total canopy water storage | capc | mm |
| Surface storage (snow) | capg | mm |
| Soil wetness in the surface layer | w1 | -- |
| Soil wetness in the root layer | w2 | -- |
| Soil wetness in the recharge layer | w3 | -- |
| Soil wetness index | swi | -- |
| Available water in the top meter of soil | s1m | mm |
| Normalized available water | naw | -- |