The time of the year in which transpiration occurs is specified as a period of months, starting with transp_beg and ending with transp_end. The specific date of the start of transpiration is computed for each HRU using the temperature index parameter transp_tmax. For each HRU, the sum of the maximum air temperatures is accumulated, starting with the first day of the month transp_beg. When the sum for an HRU exceeds transp_tmax, transpiration is assumed to begin on that HRU. This permits accounting in part for warmer or colder than normal spring periods. Transpiration ends on the last day of the month previous to transp_end. transp_on is equal to `1′ during the transpiration period.
- Leavesley, G.H., R.W. Lichty, B.M. Troutman, and L.G. Saindon, 1983, Precipitation-runoff modeling system–user’s manual: U. S. Geological Survey Water Resources Investigations report 83-4238, 207 p.