The scaling technique in Palmer Drought Severity Index; generalized calibration and modification.
The scaling technique in calculating Palmer Drought Severity Index (PDSI) has specific properties, which is considered in details, in this study. The Palmer scaling method contains a physically-based weighting factor called climatic characteristic coefficient, K. This factor, is the ratio of average moisture demand to average supply in a regional water balance, whose related coefficients and involved equation parameters should be calibrated according to any special case study. Therefore, in this study, the generalizing procedure of obtaining K-value with no dependency on particular area, in addition to some modifications in the process was analytically developed. The generalized procedure has an appropriate potential for various purposes such as; correctly identifying analytical K-formula, simplifying its application, recognizing its limitations and moreover it can be used in other researches for developing its advantages. The proposed procedure and its modifications also applied for a case study (e.g., Maharlue catchment, Fars province, Iran). The outputs of the application validated the suggested modifications; therefore, the obtained K-values can be used for other studies in the region.
Tudeshki
Ali Reza Soltani
AR
Department of Agricultural Engineering-Water, Agricultural College, Shiraz University, Shiraz, Islamic Republic of Iran.
Sichani
Sefollah Amin
SA
Nazemossadat
Saied Mohammad Jafar
SM
Karamouz
Mohammad
M
Javanmard
Soheila
S
D002138:Calibration; D004190:Disasters; D005544:Forecasting; D005843:Geography; D007492:Iran; D008956:Models, Chemical; D015233:Models, Statistical; D008962:Models, Theoretical; D012621:Seasons; D013997:Time Factors