Download DSSAT User's Guide Vol. 3 - Projetos e Redes do Macroprograma 1

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TABLE 4. WEATHER STATION INFORMATION REQUIRED
FOR A
NEW STATION.
Latitude (degrees)
Station latitude (+=N, -=S).
Longitude (degrees)
Station longitude (+=E, -=W).
Elevation (m)
Station elevation above mean sea level.
Angstrom coefficient A
Coefficient A in equation: SRAD = (A + B *
n/N) * RE, where RE is extraterrestrial radiation and n is duration of bright sunshine, and
N is daylength.
Angstrom coefficient B
Coefficient B in equation: SRAD = (A + B *
n/N) * RE.
Reference height (m)
Height of meteorological sensors above ground.
Wind reference height (m)
Height of anemometer above ground.
Mean annual temperature (°C)
Mean annual average daily temperature.
Temperature amplitude (°C)
Half the range of monthly means for average
daily temperature.
Start of growing season (d)
Mean day-of-year for last frost.
Duration growing season (d)
Mean time from last frost to first frost.
Export will be dis-abled until it has been completed. An alternative to manual
data entry is to calculate the means from the daily data in the raw archive file.
Monthly climate statistics are available from several secondary data sources (eg.
Conway, et al., 1963; NOAA, 1974; Rudloff, 1981). The last two items in the dialog box shown in Screen 16 allow you to document the data source and the data
collection period.
CALCULATE MONTHLY MEANS
The ÒCalculate monthly meansÓ option in Screen 14 allows you to compute
means from the data in the raw archive file. This is a reasonable option if there
are sufficient reliable data in the archive file or if there are no available climate
data. The user is given a warning message if there are less than five years of reliable data in the archive file. Calculating monthly means is equivalent to estimating the SIMMETEO parameters from the Generate menu (see the ÒGenerate
MenuÓ section in this Chapter). The ÒCalculate monthly meansÓ option will
overwrite manually-entered data.
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