Atmospheric pressure and Atmospheric Temperature
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Atmospheric pressure decreases with increasing altitude and is caused by the decreasing mass of air above. It is measured in units like atmospheres and pascals. The scale height is the height where pressure decreases by a factor of e and depends on temperature, molecular mass, and gravity. Atmospheric temperature also varies with altitude, from very cold in the mesopause to very warm in the thermosphere due to radiation. Mean sea level pressure is the pressure at sea level used in weather reports.
Atmospheric pressure and Atmospheric Temperature
- 1. Atmospheric Pressure and Atmospheric Temperature Andino Maseleno Alif bin Haji Alias
- 2. Atmospheric Pressure Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth (or that another planet). In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. On a given plane, low-pressure areas have less atmospheric mass above their location, whereas high-pressure areas have more atmospheric mass above their location. Likewise, as elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation.
- 3. The standard atmosphere (symbol: atm) is a unit of pressure equal to 101325 Pa or 1013.25 milibars or hectopascals.
- 4. The pressure of an atmospheric gas decreases with altitude due to the diminishing mass of gas above each location. The height at which the pressure from an atmosphere declines by a factor of e (an irrational number with a value of 2.71828..) is called the scale height and is denoted by H. For an atmosphere with a uniform temperature, the scale height is proportional to the temperature and inversely proportional to the mean molecular mass of dry air times the planet's gravitational force per unit area of on the surface of the earth. For such a model atmosphere, the pressure declines exponentially with increasing altitude. However, atmospheres are not uniform in temperature, so the exact determination of the atmospheric pressure at any particular altitude is more complex.
- 5. • The mean sea level pressure (MSLP) is the atmospheric pressure at sea level or (when measured at a given elevation on land) the station pressure reduced to sea level assuming that the temperature falls at a lapse rate of 6.5 K per km in the fictive layer of air between the station and sea level. • This is the atmospheric pressure normally given in weather reports on radio, television, and newspapers or on the Internet. When barometers in the home are set to match the local weather reports, they measure pressure reduced to sea level, not the actual local atmospheric pressure. • The reduction to sea level means that the normal range of fluctuations in atmospheric pressure is the same for everyone. The pressures that are considered high pressure or low pressure do not depend on geographical location. This makes isobars on a weather map meaningful and useful tools.
- 8. Atmospheric Temperature Atmospheric temperature is a measure of temperature at different levels of the Earth’s atmosphere. It is governed by many factors, including incoming solar radiation, humidity and altitude.
- 9. In the Earth's atmosphere, temperature varies greatly at different heights relative to the Earth’s surface. The coldest temperatures lie near the mesopause, an area approximately 85 km to 100 km above the surface. In contrast, some of the warmest temperatures can be found in the thermosphere, which receives strong ionizing radiation.