Vaisala IRIS - Page 125

2. Configure the CATCH product:
Rain1
Specify the product name of the input hourly RAIN1 product.
Select Rain1 and choose from a list of products, or type the name in the field.
When you enter a product name, the associated task information is displayed in
the TASK Summary.
Hours
Specify the number of hours to integrate. When the product runs, it integrates
data for the last N hours.
If a RAIN1 product is missing for one of the hours in the interval, the algorithm
assumes that no rain fell during that hour.
The product output shows how many hours were integrated.
Color Scale, Levels, and 1st Level/Step
Specify the color levels can be specified.
The resolution is fixed by the resolution of the RAIN1 configuration.
Subcatch
Select the subcatchment file name. The subcatchment file contains the
subcatchment definitions.
Issue Warn
The CATCH product can generate warnings if the amount of precipitation for a
subcatchment exceeds a threshold value.
The threshold value for each subcatchment area is configured in the
subcatchment file.
Oset and Multiplier
Use these values to modify the thresholdsfor each subcatchment. This might be
done to account for dierent integration times.
For no adjustment of the thresholds in the subcatchment file set Offset=0.0
and Multiplier=1.0.
Vaisala recommends that you configure the thresholds in the subcatchment file
to be characteristic of accumulation over a standard time such as one hour. You
can then use The oset and multiplier can then use Oset and Multiplier to
adjust all of the thresholds.
For example, assume that an indicator of flood hazard in a subcatchment
experience shows that the one hour threshold is 10 mm (0.39 in) and the 2 hour
threshold is 15 mm (0.59 in) for flood hazard. You can configure the 10 mm
(0.39 in) value for the subcatchment and then set the multiplier to 1.5 and the
oset to 0.0. This allows some degree of adjustment of the subcatchment
thresholds for dierent time periods.
Another technique is to configure dierent subcatchment files with the
thresholds set for dierent integration times. In this case the name of the
subcatchment file should reflect the integration time such as CATCH_06 to
indicate that the thresholds are set for 6 hours.
Chapter 5 – Configuring and Scheduling Optional IRIS Products
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