New Terrain Program
Motivation
A global 30 sec terrain elevation dataset and a global 30 sec
vegetation dataset have recently become available from USGS. The
workstation version of terrain program is therefore being updated
to take advantage of these datasets.
Program
Function
The program functions similarly to the old program if one does
not choose to use the global 30 sec dataset and new landuse option
(switches set up at the top of the deck).
Two preprocessors are added in the deck to acquire and reformat
the new 30 sec data so that much of the old terrain program can
be used.
The terrain job script can be set up to automatically acquire
data from either NCAR's MSS or USGS's anonymous ftp. The data can
also be downloaded prior to running the program. In this case, the
directory where data resides needs to be specified.
The program can be run on both Cray and workstations, but only
limited tests have been performed. The program should be considered
as experimental.
To use the 30 sec global terrain data, set script variable GLOBAL30S
to TRUE in the deck. The terrain program defines this dataset as
type 5 data, and this data may be used in place of the old 30 sec
data over the continental US.
To use the vegetation dataset to create landuse, set script variable
NewLandUse to TRUE. The new landuse datasets have data at
1 degree, 30 min, 10 min, 5 min, and 30 sec resolution.
The vegetation dataset is also used to create land-water mask
and used in the program in place of EZFUDGE option (which makes
use of NCAR Graphics' coastline information) if one chooses the
NewLandUse option.
There are two types of vegetation datasets one can choose to generate
landuse. The USGS data is nearly a global one (except Antarctica
(south of 60 S), eastern Greenland (east of 40 W), and the east
tip of Siberia (east of 180 E)), and has 24 landuse categories including
urban. The category for water is 16. The SiB dataset is North American
(60W - 180W, and 0N - 90N), and has 16 landuse categories but without
urban. The water category is 15. The SiB dataset is the same one
used in NCEP's Eta model.
Source
Datasets
Global 30 Second Elevation Data
USGS provides the 30 sec terrain data from their anonymous ftp
site:
ftp://edcftp.cr.usgs.gov/pub/data/gtopo30/global. The dataset
is archived in a total of 33 files. A tile map can be found from
the same site: tiles.gif.
Global 30 Second Vegetation Data
We have acquired the USGS global 30 sec vegetation data, and reformatted
them to latitude/longitude grid. Coarser resolution datasets at
1 degree, 30', 10', 5' were also generated from the 30 sec dataset.
We provide these datasets on anonymous ftp site:
ftp://ftp.ucar.edu/mesouser/Data/TERRAIN
The data were derived from satellite observations over a period
1992-3, and when using these categories care should be taken to
ensure that the land-uses are realistic and relevant to the area
of interest. For instance, the meaning of the "desert" classification
in the USGS data is now more limited, applying mostly to sandy deserts
such as the Sahara, while areas like Arizona, that were desert under
the 13-category definition are now "shrubland". Distinction is also
made between irrigated and unirrigated croplands. The 16-category
SiB classification also lacks an "urban" category, which would be
a drawback for fine-scale models over large urban areas.
Program
Tar File
On NCAR's anonymous ftp:
ftp://ftp.ucar.edu/mesouser/MM5V2/Terrain/terrain.tar.gz
On NCAR's MSS:
/MESOUSER/MM5V2/TERRAIN/NEW-TERRAIN.TAR.gz
How
to Run It?
-
Obtain the source code tar file from NCAR's anonymous
ftp;
-
Read the README
file inside the tar file;
-
Edit the configure.make file to set RUNTIME_SYSTEM
variable and select appropriate compiler options;
-
Type make terrain.deck to obtain the deck for your
system;
-
Edit terrain.deck to set appropriate script and namelist options;
-
Type terrain.deck to run the job.
Program
Documentation
Please read the README file
and notes near the top of terrain.deck
before running the program.
Miscellaneous
Updates
Since April 7, 99
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