Relationship between the common climatic parameters and average drought frequency

✍ Scribed by R. P. Pandey; K. S. Ramasastri

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 229 KB
• Volume: 15
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.187

✦ Synopsis

The parameters commonly considered to define climate are the mean annual precipitation and mean annual potential evapotranspiration. In this study an attempt has been made to develop a relationship between average drought frequency and the evapotranspiration/precipitation ratio for the arid, semi-arid and subhumid climatic regions of India. The climatic regions are delineated using two climatic indices: namely (i) the ratio of mean annual precipitation P a to global terrestrial mean annual precipitation P g , and (ii) the ratio of mean annual potential evapotranspiration E p to mean annual precipitation P a . It was noted that the average drought frequency (i e., year 1 .) decreases gradually from dry to wet regions. The return period varies from 2 to 3 years in the arid regions 12 > E p /P a ½ 5 , 3 to 5 years in semi-arid regions 5 > E p /P a ½ 2 , and 5 to 8 years in sub-humid regions 2 > E p /P a ½ 3/4 . Another relationship was developed between the average frequency of drought occurrence and the ratio of mean annual deficit to mean annual precipitation, E p P a /P a . The results have been compared with the drought experiences documented for other regions of the world.