Difference between revisions of "Distributed HMET Data"

Revision as of 17:13, 21 December 2012

The main benefit of using distributed hydrometeorology (HMET) data in GSSHA is that the entire model does not have to use the same hourly data values throughout the entire domain. The temperature, cloud cover, direct radiation, global radiation, pressure, relative humidity, and wind speed can be spatially varied over the entire model domain. This is more realistic than assuming the entire domain has the same uniform hourly values for these data. Precipitation data can also be input into the GSSHA model using Arc/Info ASCII grids of rainfall, as shown in http://www.gsshawiki.com/gssha/Precipitation:Spatially_and_Temporally_Varied_Precipitation.

Currently, if one piece of data is input in raster form, all data must be input in raster form. This means that if temperature data is input in a Arc/Info ASCII grid, all HMET data must be input in the same form. Below is shown how to input distributed HMET Data into the GSSHA model.

Distributed HMET Input Card - Optional

HMET_ASCII  ***.txt

Distributed HMET Input File
The distributed HMET input file has a specific format and must reflect hourly HMET data files. All of the HMET data files, as explained below, must be in the same folder and have the same heading. The distributed HMET input file points the model to the location of the HMET data files. The format for the distributed HMET input file is as follows:

FILEPATH\yyyymmddhh

example:
C:\GSSHA_Projects\HMET_DATA\2012013121
C:\GSSHA_Projects\HMET_DATA\2012013122
C:\GSSHA_Projects\HMET_DATA\2012013123
C:\GSSHA_Projects\HMET_DATA\2012020100
C:\GSSHA_Projects\HMET_DATA\2012020102
C:\GSSHA_Projects\HMET_DATA\2012020103

Distributed HMET Arc/Info ASCII File Format
All of the HMET data must have the same format of Arc/Info ASCII File, as shown below:

ncols ####
nrows ####
xllcorner ####.####
yllcorner ####.####
cellsize ####.####
NODATA_value ####.####

1. 1. 1. 1. .#### ####.#### ####.#### ####.#### .........
            
         2. .#### ####.#### ####.#### ####.#### .........
            
         3. .#### ####.#### ####.#### ####.#### .........
            

.........
.........
.........
.........

Distributed HMET Arc/Info ASCII Files
Each HMET data file has a unique file name to indicate year, month, day, hour, and data type. The chart below describes the HMET data file names and units.

Temperature

Cloud Cover

Direct Radiation

Global Radiation

Pressure

Relative Humidity

Wind Speed