1.Introduction.There are two main types of climates, hot and cold. In Pakistan we have both. Today we will see hot climate. Hot climate in Pakistan starts from the month of March and prevails till the month of September. In Rahwali hot climate is coupled with moisture and that is because of monsoon. 2.Aim. To teach the phenomenon of monsoon in Pakistan and flying hazards associated with it. 3.Preview
b.Climate of Pakistan.
c.What is monsoon?
(1)Area of origin of monsoon.
(3)Trigger actions and controlling factors.
(4)Time span of monsoon.
e.Weather of Rahwali during monsoon.
4.Climate of Pakistan.Pakistan is in the temperate zone and varies greatly in weather conditions. Pakistan has coastal belt in the South. In the north Pakistan has snow covered peaks with Plains, deserts and few mountain ranges in between. Climate of Pakistan observed over last 20 years is as under:- a.Winter (December – February).In winter temperature may drop to -25 degree Celsius in northern areas and is 3 to 5 degrees Celsius in costal city of Karachi. b.Spring (March – May).In spring Temperature rises and weather become moderate to hot. c.Summer/ Monsoon (June – September). During this period hot and humid weather is observed east of Indus river however hot and comparatively less humid weather is observed west of river Indus. d.Fall Season/ Retreating Monsoon (October – November).When monsoon retreats, temperatures start to fall and fall season sets in. 5.Monsoon. The English word “MONSOON” has been derived from Arabic word موسم (mausam "season or weather"). The Arabic-origin word موسم (mausam) is also the word for "weather" in Urdu. a.Dictionary Meaning
(1)Encarta.Monsoon is defined as a major wind system that seasonally reverses its direction, accompanied by seasonal changes in precipitation. (2)Word web.Rainy season in southern Asia when the southwestern monsoon blows, bringing heavy rains. (3)Oxford.A strong wind in and near Indian ocean.
b.History.The earliest explanation for monsoon development came in 1686 from the English astronomer and mathematician Edmond Halley. Halley is the man who first conceived the idea that differential heating of land and ocean caused these giant sea-breeze circulations.
c.Monsoons in the World.The major monsoon systems of the world consist of the Indian monsoon, West African monsoon, Malaysian - Australian monsoon and Pacific coast of central American monsoon. d.Indian Monsoon.Indian monsoon is the system which affects Pakistan. In this system winds from Arabian Sea and Indian Ocean laden with moisture blow to the lands of Pakistan, India and Bangladesh and result in heavy rain fall. 6.Area of Origin of Monsoon.The huge land areas of sub-continent are located close to equatorial latitudes, where extensive heating takes place in summer season. These areas include Thar desert (extension of which is Choolistan desert south of Sutlej river in Pakistan), Thal desert (between Indus and Jehlum river), land of Ganges river in India and deserts of Balochistan. Due to this heating a low pressure area starts to develop over Indian subcontinent, which deepens to full extent by the month of June. There is always a belt of high pressure around 30 degree North and 30 degree South latitudes. In summers, southern high moves towards equator and further forces the winds from Indian Ocean and Arabian Sea to move inland to the subcontinent. Monsoon originates from Indian Ocean and Arabian Sea and then it travels to Indian Subcontinent. 7.Monsoon Path.Due to pressure difference over land and ocean winds start to blow from Southern Oceans to northern land. Under the influence of pressure gradient force and geostraphic force ultimately taking a South West direction. The phenomenon of monsoon is similar to that of sea breeze but it occurs on a very large scale. These...