Define the following factors affecting the temperature of Pakistan:
1. Altitude and temperature.
2. Cloud cover and temperature.
Answers
Factors influencing temperature are as follows:
1. Latitude: Since the earth’s crust is curved, the sun ‘s vertical ray strike different parts of the earth surface at different angles. At the equator, the vertical rays hit the earth’s surface at an angle of 90◦(angle of incidence) towards the poles.
2. Altitude: At the higher altitudes , the amount of atmosphere decreases and as the result there is less water vapour in the air. The atmosphere absorbs less heat and therefore the temperature at higher altitude drops.
3. Distance from the sea: The difference in heating of land and water affects the temperature of places located near the coast differently from those located inland.
4. Ocean currents: Ocean currents are large streams of water flowing in the oceans. These generated when winds blow over the water surface.
5. Humidity: Humidity is the amount of water vapour in the atmosphere and its influences the cloud cover in the sky. The higher the humidity the greater amount of cloud cover. The lower the humidity the less amount of cloud cover.
6. Cloud cover: Place near the equator has greater amount of cloud cover. Areas in the desert where humidity is low will have lower amount of cloud cover.
7. Aspect: Aspect is the direction in which a slope faces in relation to the sun. In the tropical areas the aspect is not much importance because the sun is high in the sky during mid day. In the temperate areas, the sun is low angle in winter, this will affect the temperature of slopes that face north to south. In north hemisphere, the south facing slope receive greater concentration of solar radiation and usually warmer than the north facing slope.
8. Types of land surface: Dense forest– the vegetation prevents solar radiation from reaching the ground directly. The ground remain cool. In the city– the presence of concrete surface tends to keep the air temperature high. The concrete surface absorb heat during the day and retain the heat at night.