Geography Assignment week 5
Question 1
The air surrounding human beings have weight and presses against everything they get in touch. This pressure is called air pressure or atmospheric pressure. Therefore, air pressure is the force exerted on the earth’s surface by air above due to the force of gravity (Singh et al., 2009). Atmospheric pressure decreases with an increase in altitude. The pressure at any level in the atmosphere is interpreted as the total weight of air above a surface unit area at elevation. Thus, at higher elevations, there are fewer air molecules above the surface than at a given surface at lower levels. Therefore, as one goes up at higher altitudes, the air pressure decreases. When the air is heated, the particles collide against each other due to the force exerted. This causes the air molecules to move more quickly, thus increasing the rate of collision. As a result, more force is exerted at each molecule leading to a rise in the air pressure.
Question 2
The pressure gradient refers to any change of pressure over a given distance. In most cases, air moves from areas of high pressure to areas with low-pressure concentration. Therefore, as the gradient becomes steeper, the gradient force increases, leading to more strong winds. A steep pressure gradient means a significant change in pressure over a short distance (Sana, & Tanaka, 2010). A steep gradient shows up on the surface map with the isobars drawn close together.
Question 3
An anticyclone is an area of high pressure where the air masses move apart and sinks. Typically, anticyclones indicate fair weather. In an anticyclone, winds move in a counterclockwise direction in the Southern Hemisphere and clockwise direction in the Northern Hemisphere (Roullet, & Klein, 2010). The airs that are concentrated at the center of an anticyclone are forced away from their high concentration areas and replaced by a blast of downward air from high altitudes. As the air moves downwards, it is compressed and heated up, thus reducing the humidity, which instead leads to fewer clouds within the anticyclone.
Question 4
A cyclone refers to the area of low pressure where the air masses meet and rise to the atmosphere. Typically, cyclones describe lousy weather conditions such as rains and clouds. In a hurricane, winds blow in a clockwise direction in the southern atmosphere and counterclockwise in the Northern hemisphere (Roullet, & Klein, 2010). Similarly, in a cyclone, the air pressure is pushed towards areas with a low-pressure concentration of the cyclone. Afterward, they rise, expand, and cool as they move. As they cool, the air that is rising becomes more humid, which leads to high humidity and cloudiness within the cyclone.
Question 5
The surface friction slows down and combines with other surface forces to control the wind direction (Coor, 2013). The impacts of surface friction may extend to about 500 m above the sea levels. Thus, the winds near the earth’s surface area affected by friction. On the other hand, the winds at the upper atmosphere usually flow parallel to the isobars as a result of slow in the Coriolis force hence making the pressure gradient pressure to become more dominant. This results in a slight deflection of wind towards areas with low pressure.
References
Coor, A. F. (2013). Winds in the upper atmosphere and Surface atmosphere. The Astronomical Journal, 65, 50. doi:10.1086/108139
Roullet, G., & Klein, P. (2010). Cyclone-anticyclone asymmetry in geophysical turbulence. Physical Review Letters, 104(21). doi:10.1103/physrevlett.104.218501
Sana, A., & Tanaka, H. (2010). Two-equation turbulence modeling of an oscillatory boundary layer under a steep pressure gradient. Canadian Journal of Civil Engineering, 37(4), 648-656. doi:10.1139/l10-009
Singh, S. P., Singh, J., Stallings, J., Burgess, G., & Saha, K. (2009). Measurement and analysis of temperature and pressure in high altitude air shipments. Packaging Technology and Science, n/a-n/a. doi:10.1002/pts.877