Climate of Pakistan

Climate and Weather

Climate: Weather is generalization of the day to day weather conditions over a long period of time usually thirty years.

Weather: Weather refers to the atmospheric conditions of any place for a short period of time (temporary changes in the climate)

Difference between weather and climate

WEATHER: Weather is what conditions of the atmosphere are over a short period of time.

CLIMATE: Climate is how the atmosphere "behaves" over relatively long periods of time.

Seasons of Pakistan

Pakistan has four seasons Winter (mid December to March) Early summer (April to June) Late summer (July to September) Post monsoon (October to Mid December)

Rainfall

The quantity of water, expressed in inches, precipitated as rain, snow,

hail, or sleet in a specified area and time interval. Only in a few northern areas humid conditions are found. The rainfall

in Pakistan is highest in northern areas decreases towards south.

Sources of rainfall in Pakistan: Monsoon winds The Western Depression Convectional Currents Relief rainfall

Tropical cyclones

Monsoon winds:

Monsoon winds are seasonal winds which blow during summer and winter. The summer winds are called South-west monsoons and the winter winds are called North-east monsoons.

South-west monsoon are giant sea breezes which bring rainfall. the rains began when the ocean are less heated and land is more heated. The air from the land rises developing a low pressure and it attracts the cool air causing heavy rainfall.

North-east monsoons blow from the land towards the sea.

Western depression

Western Depression are the cyclones which originate in Mediterranean Sea, they travel across Afghanistan and Iran and then reach the western part of Pakistan. The moisture in the air is evaporated causing rainfall.

Convectional currents

Hot air rises during summer and when it reaches the high layer of atmosphere, condensation takes place causing rainfall. Strong winds accompanying the storms may pick up dust with them

Only northern and north western areas of Pakistan receive rainfall from Convectional currents. Southern Pakistan despite being more hot then the northern areas experience less rainfall because of temperature inversion layer.

Relief rainfall:

Relief rainfall is related to the height of land. It occurs where moist unstable air moves up a mountain edge and it is chilled, heavy condensation takes place and rainfall occurs.

Tropical cyclones:

Tropical cyclones bring heavy rainfall for few hours and can cause a lot of destruction. They originate in Arabian Sea quite often but rarely reach the coast of Pakistan. Therefore, this source of rainfall is totally unreliable.

Climatic zones of Pakistan

Highland Zone: Region: Northern, north western and western highlands. Areas: Chitral, Murree, Muzzafarabad, Drosh, Quetta,

Kalat, Parachinar, Waziristan Climate: the winters are long, cold and snowy and

summers remain short and mild Rainfall is normally associated with altitude. Rainfall in

Northern Mountain is highest in the highland zone. Rainfall in the western mountain is less

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

North: Summers are short and mild because of transfer of heat from central Pakistan and high angle of sun.

Winters are very cold because of high altitude and low angle of sun.

West: summers are dry and warm in Western mountain because of continental effect, aridity and high angle of sun

Winters are mild warm because of low angle of sun, altitude and Western Depressions.

The growth of tress is retarded because of severe cold winters. At some places rivers and torrents also freeze and during winter farming is not practiced and people are involved in indoor activities.

Transhumance is also practiced People live their as nomadic herdsman Many northern areas are not accessible due to

landslides and heavy snowfall Lack of water supple discourages human settlements

Sources of rainfall:

Relief rainfall Monsoon rainfall Thunderstorms Western Depression

Arid zone

Regions: south-eastern desert, and south-western Balochistan Areas: Kharran Desert south-western Balochistan, south-eastern

desert. Climate: It is markedly dry and hot. Hot dusty winds prevail continuously from

mid –May to mid-September, rainfall takes place during winter season in south-western Balochistan, in south eastern desert monsoons bring little rainfall. Extreme heat, dust storms are the main features of this arid climate.

Winters are cool-mild because of low angle of sun, summers are hot because of high angle of sun. Summers are very hot during the day.

Life and Economic activities

The region is deficient of moisture. the temperature is so extreme that it isn’t suitable for habitation or

cultivation. The majority of people are nomadic, they move from one place to another

with their animals. Because rainfall is very low that’s why unique system of karez is

established. Through perennial canals many areas are irrigated. People there wear thick and rough clothes in order to protect them

from extreme heat. They move from one place to another in search of water. Source of rainfall Little rainfall from Western Depression and monsoon winds.

Lowland Zone – Semi arid to arid

Region: Indus plain except the Coastal areas. Areas: Islamabad, Sialkot, Sarghoda, Multan, Jacobabad, and

Sukkur Climate: It has arid and extreme climate with hot summers, cool winters and

summer monsoon rainfall. Thunderstorms are also common in north and north-west of the

Indus plain. The upper Indus plain and Lower Indus plain there’s less rainfall and spells of very high temperature.

Winters are cool-mild because of low angle of sun and continental effect and summers are hot due to high angle of sun and continental effect.

Life and Economic activities:

The plain is drained through four tributaries of Indus River, economically; it is the most productive region of Pakistan. There is a well developed canal system and many crops are grown there such as millet, wheat, cotton and sugarcane

Population is high and there’s moderate rainfall and tolerable temperature.

Sources of rainfall:

Convectional rainfall in northern Punjab Western depression in northern Punjab Monsoon rainfall

Coastal zone

Region: Indus Delta, Karachi and Makran coast Areas: Karachi, Jiwani, Pasni, Ormara and Gwadar Climate: The climate is dominated by sea breezes throughout the year; the maritime

influence keeps the daily temperature low. The temperature on land and sea is different; land and water absorb the sun’s heat and water and also radiate it. In summer the land heats up, while ocean remains cool. In winter the land loses heat quickly and becomes cold while ocean remains hot.

The humidity level is usually high, more than 50% from April to September. Means monthly temperature is 32 ۫C and May, June and October are the hottest month.

During October the climate is dominated by dry winds from south-eastern desert. Rainfall is scanty; the rainfall is experienced during monsoon season.

Life and economic activities:

The rainfall takes place during monsoon season, many tourist visit Karachi in November and February and most of the social events are held in these months. The extent of precipitation affects the supply of drinking water in Gwadar. The development of Gwadar port had made is a major district of Pakistan and had contributed in the economic development of Balochistan.

Economic activities could be carried out throughout the year because of moderate climate. Farming is possible, the sea ports are operational throughout the year in order to carry international trade, roads and rail transport links are never closed in the year for the businesses, air flights are rarely cancelled, all types of industries are present there.

However, during summer months, tropical cyclones sometimes cause coastal flooding in low-lying areas causing damage to infrastructure. Fishing is nearly impossible when the sea is wild and fishing communities face losses.

Sources of rainfall:

Monsoon rainfall Western depression Tropical cyclones

Factors affecting temperature of Pakistan

Latitudinal effect: The areas that lie near the equator encounter more amounts of sun rays than the areas that don’t

lie near the equator. Southern Pakistan receives more amounts of sun rays as compared to Northern Pakistan.

Continental effect: The areas that are away from the sea are unaffected by maritime influence, consequently; they

are more hot as compared to areas near sea. Winters are extreme and summer temperatures are quite severe

Altitude and temperature Cloud cover and temperature In daytime cloud cover reduces the amount of heat by reflecting the heat back to the space but in

night time it traps the out going heat and because of this the cloudy nights are warm. Latitude and angle of sun The sun rays don’t fall at the same angle everywhere. During summer, the northern hemisphere is tilted towards the sun and the northern areas of

Pakistan absorb more heat because of high angle of sun, during winter the northern hemisphere is tilted away from the sun and the northern areas experience sun for shorter duration.

River flood

Overflow of large amount of water beyond its normal limit, especially over what is normally dry land.

Rivers are considered by many people around the country as the best place for economic development. Water is tentatively an imperative resource for human beings but its excess may lead to disaster. Excessive water in rivers bring flood

Reasons of floods

The current flooding in Pakistan is mainly due to climate change. It is the unusual climate-change-led seasonal cycle of land temperature in Pakistan that has exacerbated the monsoon rainfall and produced the hugest volume of water in the northern mountainous region of the country ever recorded in the history, causing floods in the Indus river basin.

The wood is in demand and because of this there’s excessive cutting of tress which increases surface run off, the trees mangroves act as a barrier and they can protect the settlements from floods but because of increasing industrialization and urbanization the water pollution is increasing threatening mangroves

The embankments around the river are not heightened, water easily reaches the settlements.

The dams don’t have much capacity to store water and because of this extra water is not store causing flood.

Ways to reduce the risk of floods

Planting more trees in order to keep check of the flow of water Build levees in order to prevent the spread of floodwater Stop building on floodplains Build flood controlling Dams. 

Building Canals (Drains of Extra Water). Using less greenhouse gases and reducing pollution in order to stop global warming which is one of the major causes of floods

Prevent Soil Erosion. Do not build on high flood risk area. 

Flood warning should be given through media Floodwater must be drained out and facilities to the refugees must

be provided

Effects of flood

The farmers aren’t able to use the land until the water drains; they face destruction of crops and loss of food supplies. The load of river improve the fertility of land

the houses will cut off from the shops and services, mud houses are damaged and water-borne diseases are spread

The transport system is severely affected, roads and railway tracks are damaged and old routes are arduous to follow because they are drained with water.

precautions

During monsoon season they must move to somewhere else in order to protect their livestock

Local residents should change their place and arrangements should be made in order to fulfill the basic necessities of life.

The transport authorities should prepare a precaution plan and should tell the transporters about the alternative ways. Roads and railway tracks must be repaired on an emergency basis.

Benefits of floods

Floods return nutrients to the land and contribute to the health of wetlands

Floods distribute rich sediments and refresh stream. A flooded field could be used to cultivate rice

Allowing rivers and streams to overflow can prevent more serious flooding

The high level of fish production because of nutrients

Floods recharge the ground water supplies.

Storms

A storm is any disturbed state of an astronomical body's atmosphere especially affecting its surface, and strongly implying severe. It may be marked by strong wind, hail, thunder and/or lightning (a thunderstorm), heavy precipitation (snowstorm, rainstorm), heavy freezing rain (ice storm), strong winds (tropical cyclone, windstorm), or wind transporting some substance through the atmosphere 

Drought Drought is an extended period when a region notes a deficiency in its water supply.

A drought can last for months or years, or may be declared after as few as 15 days. Generally, this occurs when a region receives consistently below average precipitation

There are four ways of categorizing drought Permanent drought Exist where crop cultivation isn’t possible Seasonal drought: Occurs in areas with well-defined rainy and dry season Invisible drought: It is the result of a water deficiency that reduces crop yields Unpredictable drought It is the result of abnormally low rainfall

Causes of drought

Natural Unreliability of monsoon winds may lead to seasonal drought The dry and hot winds can reduce the moisture contents of sandy

soil Global climate is constantly changing leading to changes in

Pakistan’s climate Human Deforestation on foothills increase soil erosion and reduces rainfall Mismanagement of water resources The disputed and unfair distribution of water Over grazing of land Global warming

Effects of drought

The effects of drought on physical environment are sever, the land is turned into a desert and because of this the soil is exposed leading to soil erosion, many species are extinct because of lack of food. There’s rise in temperature and loss of vegetation, because of low precipitation there’s extension of desert areas.

Drought not only effect physical environment but also human environment, drought affect

Population Loss of life because of widespread famines, malnutrition, health

problems and starvation Nomadic lifestyle because people migrate from the areas that are

affected by drought and because of this urbanization is increased causing an increase in domestic waste leading to water pollution.

Drought management

Water storage schemes: reservoirs and dams should be built in order to store water and some traditional methods should also be utilized in oreder to store water. The areas that receive heavy rainfall can utilize the water through perennial canal system. More projects are required in order to mett the needs of people.

New methods should be used, desalination process should be used, conversion of waste water in to clean water through chemical treatment

Drought resistant seeds should be used High priority should be given to the allocation of water to

industrial areas and to meet the basic needs of people.