Distribution of Rainfall & Climatic Regions of India
Distribution of Rainfall
- Average annual rainfall 125 cm
- Areas of High Rainfall (Exceed 200 cm): Western Ghats (400 cm annually), as well as in the sub-Himalayan areas is the northeast and the hills of Meghalaya. Khasi and Jaintia hills – 1000 cm, Brahmaputra valley – less than 200 cm.
- Areas of Medium Rainfall (100 – 200 cm): southern parts of Gujarat, east Tamil Nadu, northeastern Peninsula covering Odisha, Jharkhand, Bihar, eastern Madhya Pradesh, northern Ganga plain along the sub-Himalayas and the Cachar Valley and Manipur.
- Areas of Low Rainfall (50 – 100 cm): Western Uttar Pradesh, Delhi, Haryana, Punjab, Jammu and Kashmir, eastern Rajasthan, Gujarat and Deccan Plateau.
- Areas of Inadequate Rainfall (Below 50 cm): Andhra Pradesh, Karnataka and Maharashtra, Ladakh and most of western Rajasthan
- Low in the interior of the Deccan plateau, and east of the Sahyadris.
- Snowfall is restricted to the Himalayan region.
Variability of Rainfall
C.V = Standard Deviation x 100
Mean
- Coefficient of variation less than 25% exists on the western coasts, Western Ghats, northeastern Peninsula, eastern plains of the Ganga, north eastern India, Uttarakhand and Himachal Pradesh and south-western part of Jammu and Kashmir - Rainfall over 100 cm.
- Over 50% exists in the western part of Rajasthan, northern part of Jammu and Kashmir and interior parts of the Deccan plateau - Rainfall less than 50 cm.
- variability of 25-50% and these areas - Rainfall between 50 -100 cm
Climatic Regions of India
Major climatic types of India based on Koeppen’s scheme.
- Tropical climates – over 18° C.
- Dry climates - precipitation is very low. dryness is less, it is semi-arid(S); if it is more, the climate is arid(W).
- Warm temperate climates - 18°C and minus 3°C.
- Cool temperate climates - warmest month (10°C) & coldest month is under minus 3°C.
- Ice Climate – under 10°C.
Sub-types: f (sufficient precipitation), m (rain forest despite a dry monsoon season), w (dry season in winter), h (dry and hot), c (less than four months with mean temperature over 10°C), and g (Gangetic plain).
Type of Climate | Areas |
Amw Monsoon with short dry season | West coast of India south of Goa |
As – Monsoon with dry summer | Coromandel coast of Tamil Nadu |
Aw – Tripical savannah | Most of the Peninsular plateaus, south of the Tropic of Cancer |
Bwhw – Semi-arid steppe climate | North-western Gujarat, some parts of western Rajasthan and Punjab |
Bwhw – Hot desert | Extreme western Rajasthan |
Cwg – Monsoon with dry winter | Ganga plain, eastern Rajasthan, northern Madhya Pradesh, most of North-east India |
Dfc – Cold humid winter with short summer | Arunachal Pradesh |
E – Polar type | Jammu and Kashmir, Himachal Pradesh and Uttarakhand |
Monsoons and the Economic Life in India
- Revolves the entire agricultural cycle of India because 64 per cent people of India depend on agriculture.
- Except Himalayas all the parts of the country have temperature above the threashold level to grow the crops or plants throughout the year.
- Regional variations – Growing various types of crop.
- Variability brings droughts or floods.
- Agriculture Depend timely and adequately distributed rainfall. If fails adversely affect irrigation.
- Sudden monsoon burst – Soil Erosion.
- Winter rainfall by temperate cyclones highly beneficial for rabi crops.
- Regional climatic variation in India is reflected in the vast variety of food, clothes and house types.
Global Warming
- Greenhouse effect.
- Green House Gas - methane, chlorofluorocarbons, and nitrous oxide which are present in much smaller concentrations in the atmosphere, together with carbon dioxide.
- 2,100, global temperature will increase by about 2°C as a result of melting of glaciers and sea-ice due to warming
- 48 cm by the end of twenty first century incidence of annual flooding, promote insect borne diseases.
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