CLIMATIC REGIONS OF INDIA

CLIMATIC REGIONS OF INDIA There are three major schemes of cla~sifying the climatic regions of India.

(i) Koppen's scheme is based on ~he monthly values of temperature and precipitation. Koppen identified five major climatic types-tropical climates, dry climates, warm climates, snow climates and ice climates. He used letter symbols A, B, C, D and E to denote these climatic types. These five types can be further subdivided into sub-types on the basis of seasonal variations in the distribution pattern of rainfall and temperature. Koppen used small letters such as m, w or h to define these sub-types.
Based on Koppen's method (see map), India can be
divided into the following climatic regions:
1. Monsoon type with short dry season (Amw)
2. Monsoon type with dry season in summers (As) 3. Tropical savannah type (Aw)
4. Semi-arid steppe climate (BShw)
5. Hot desert type (Bwhw)
6. Monsoon type with dry winters (Cwg)
7. Cold-humid winter type with short summers (Dfc) 8. Polar type (E)

(ii) Thornthwaite's scheme Thornthwajte's scheme is
based on the concept of water balance. If the rainfall of a place is less than the water which is lost through evaporation and transpiration, the place has a water deficit. If it is more than the need, then there is a surplus.
Thornthwaite evolved a formula to work out the monthly values of water surplus and water deficit. Areas having water surplus in all the months of the year have a humid climate and areas having water deficit ­
in all the months of the year have an arid climate. In between these two extremes, there are other types with varying degrees of water surplus or water deficit.
On the basis of Thornthwaite's method (see map), the following climate regions can be identified:
1. Perhumid(A)
2. Humid (B)
3. Moist sub-humid (Cz)
4. Dry sub-humid (C)
5. Semi-arid (D)
6. Arid (E)