climatic zones of pakistan

Saad FarooqiSaad FarooqiBS-Environmental SciencesBS-Environmental Sciences55thth Semester SemesterDepartment of Environmental And Department of Environmental And Conservation SciencesConservation SciencesUniversity of SwatUniversity of Swat

Weather and Climate

WeatherWeather refers to the atmospheric conditions (temperature, rainfall, humidity and pressure) of any place for a short period of time. It is often localized.

ClimateClimate is a generalization of the day to day weather conditions over a long period of time, usually thirty years.

Climatic Zones of Pakistan

Pakistan extends from 24° N to about 37° N.Its western border lies close to 62°E, its northeastern

border extends to about 74○E, while Kashmir extends to 80° E.

To the north of West Pakistan lie the lofty mountainous ranges of the Pir Panjal, the greater Himalaya and the Karakoram ranges.

CONTDThe Sulaiman mountains are in the northwest, while

Koh-i-Taftan and then lower ranges in continuation of the Namak-sar desert beyond them lie to the west, between Pakistan and Iran.

These physical features have a great bearing on the climatology of the area in so much as they not only modify rainfall and temperature pattern of West Pakistan, but also greatly influence the general circulation of the atmosphere in the Sub-continent.

CONTDPakistan's topographical features range

from lofty mountains in the north to the coastal plains in the south.

Climatic divisions of Pakistan are:A.Highland climateB.Lowland climateC.Coastal climateD.Arid climate

CONTDZone A indicates highland climate prevailing over

northern, north-western and western mountains. Zone B has lowland climate, which prevails over the

whole of the Indus Plain.Zone C has coastal climate experienced by the

Makran Coast, Karachi Coast and Indus Delta till the Rann of Kutch.

Zone D has arid climate and includes the south-eastern desert and south-western part of Balochistan.

A division of climatic zones does not imply exactly the same conditions throughout the zone.

There are great variations in rainfall, temperature, humidity etc in the same climatic zone.

For example, northern highlands and western highlands fall in the same climatic zone but the amount and seasonal distribution of rainfall is different.

Murree and Hazara hills experience more than 1500 mm average annual rainfall mostly during the summer season, whereas in the western highlands Quetta and Pishin receive 250 - 500 mm average annual rainfall.

A. Highland Climate

This region includes northern, north-western and western highlands.

The winter are long, cold and snowy and the summers remain short and mild.

In mountainous areas rainfall is normally associated with altitude.

The height of the northern mountains range from 2000 meters to above 8000 meters, while in the western mountains the height is approximately from 1000 to over 4000 meters.

CONTDRainfall in the northern mountains is the highest in

the highland zone.The western mountains experience less rainfall.From south of Kohat and Waziristan rainfall

decreases and occurs during the winter season. To the north-west, Gilgit and Chitral also experience

low rainfall, as they are rainshadow areas.

CONTD

The temperature conditions also vary from north to west depending on the altitude.

Summers are short, mild and wet in the northern mountains but dry and warm in the western mountains.

B. Lowland Climate (Semi-arid to arid)

This region includes the whole of the Indus Plain except the coastal areas.

Most parts of the Indus Plain lie at the western end of the tropical monsoon zone.

It has arid and extreme climate with hot summers, cool winters and summer monsoon rainfall.

The amount of rainfall differs from north to south.

CONTDThe foothills of the northern mountains and

Potwar Plateau are wetter than the Indus Plain, and also receive rainfall from Western Depressions.

Thunderstorms are also common in the north and north-west of the Indus Plain.

The southern Upper Indus Plain and the whole of the Lower Indus Plain have much less rainfall and spells of very high temperature.

C. Coastal Climate:

The region includes the southern coastal strip comprising of the Indus Delta, Karachi and the whole of the Makran coast.

The climate is dominated by sea breezes throughout the year.

The maritime influence keeps the daily range of temperature low.

CONTD

Maritime or coastal climate is explained in Fig. 2.2.

CONTDThis shows that the influence of sea is left mainly

through the prevailing winds. The temperature at sea and on land is different owing

to unequal heating of land and water by the sun. Land and water absorb the sun's heat at different

rates, and also radiate or lose it at different speeds. In summer the land heats up, while the ocean

remains comparatively cool.

CONTDIn summer the land heats up, while the ocean remains

comparatively cool. In winter the land loses heat quickly and becomes cold

while the ocean is much warmer and keeps its warmth for a long time.

The humidity level is moderately high, exceeding more than 50% from April to September.

CONTDMean monthly temperature is 32○C, and May, June and

October are the hottest months. During October dry winds from the south-eastern desert

dominate the climate.Rainfall is scanty throughout the year.From Karachi up to the Rann of Kutch, the coast

experiences most of its rainfall during the monsoon season, while on the Makran coast it falls in winter.

D. Arid Climate:An arid climate is experienced in south-western

Balochistan and the south-eastern desert.It is markedly dry and hot.Hot dusty winds prevail almost continuously from

mid-May to mid-September.Most of the scanty rainfall in south-western

Balochistan takes place during the winter season.In the south-eastern desert, summer monsoons bring

little rainfall.Extreme heat, dryness and dust storms are the main

features of this arid climate.

References:

Ahmad SQ, Abbasi AA. 1962. Pakistan

Geographical review. Pakistan International

Printers Lahore. Vol 17: 9.

Sethi NH. 2007. Environment of Pakistan. Peak

Publishing. 2nd edition: 23, 24.