Climate Data

Climate data is needed for each reach if you want WEAP to model water temperature. The climate parameters include:

• Air Temperature - the weighted mean of high and low temperature.

• Humidity - relative humidity

• Wind - average wind speed in m/s. Default is 2 m/s.

• Cloudiness Fraction - fraction of daytime hours with no shade from clouds, vegetation or topography (0.0=completely overcast or shaded, 1.0=no clouds or shade). Default is 1 (no shade).

• Latitude - in degrees

• Net Solar Radiation - in MJ/m^2/day.  Optional: enter data for net solar radiation to override WEAP's calculation (based on Latitude, Air Temperature, Relative Humidity and Cloudiness Fraction).  If you override WEAP's calculation, you do not need to have data for latitude and cloudiness fraction, but you still do need data for Air Temperature, Humidity and Wind.1

If you are using QUAL2K to model water temperature, the following climate parameters are required:

• Air Temperature - the weighted mean of high and low temperature for the timestep.

• Dew Point Temperature - temperature to which the air would have to cool in order to reach saturation. The closer dew point is to the air temperature, the higher the relative humidity. Dew point cannot be higher than air temperature.

• Wind - average wind speed

• Cloud Cover - average percent of daytime that the river is shaded by clouds

• Shade - percent of solar radiation that is blocked because of shade from topography and vegetation.

Whether modeled by WEAP or QUAL2K, if any of the climate data for a reach are left blank, the values from the immediate upstream reach will be used. Therefore, if the climate is the same for all reaches, you only need to enter the data for the first reach.

Entered on: Data View, Branch: Supply and Resources \ River \ <River Name> \ Reaches, Category: Climate, Tabs: Air Temperature, Humidity, Wind, Latitude, Dew Point Temperature, Cloud Cover, Shade.