On the mediterranean climatic regime of West Pakistan

Abstract

Taking mediterranean climate as one having mild winter, rainfall during the cool seasons of the year and summer drought, the stations of West Pakistan subject to this climate are listed. Degrees of mediterraneity are recognized on the basis of intensity of estival dryness (summer rainfall as percentage of the total). Three categories are recognised and mapped out: pure mediterranean (e. g. Nokkundi: no summer rain), moderate mediterraneity (<40% summer rains on an average, e. g. Quetta, Kalat), attenuated mediterraneity (>40% rainfall in hot season) marking a transition towards tropical or bixeric climates (e. g. Fort Sandeman, Dera Ismail Khan). Whereas the stations of tropical regime have the highest coefficient of variation of rainfall and number of rainy days during cool seasons and the least during summer, contrary is the case for the stations having moderate degree of mediterraneity. For those of attenuated character, the position is more or less intermediate but leaning towards tropical regime. In tropical and bixeric climates, it is the summer rainfall (and number of rainy days during summer) expressed as percentage of the annual total that occupies the dominant position; in the moderate mediterranean regime, winter has the most prominent position followed by spring-autumn and then by summer. Further attenuation in the degree of mediterraneity is marked by corresponding increase in summer rainfall.