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z is the elevation in meters, R is the specific gas constant = 287.053 J/(kg K) T is the absolute temperature in kelvins = 288.15 K at sea level, g is the acceleration due to gravity = 9.806 65 m/s 2 at sea level, P is the pressure at a given point at elevation z in Pascals, and; P 0 is pressure at the reference point = 101,325 Pa at sea level.
For example, if a station reports that the 500 mb [i.e. millibar] height at its location is 5600 m, it means that the level of the atmosphere over that station at which the atmospheric pressure is 500 mb is 5600 meters above sea level. This is an estimated height based on temperature and pressure data." [6]
The concept of potential temperature applies to any stratified fluid. It is most frequently used in the atmospheric sciences and oceanography. [2] The reason that it is used in both fields is that changes in pressure can result in warmer fluid residing under colder fluid – examples being dropping air temperature with altitude and increasing water temperature with depth in very deep ocean ...
With a temperature lapse rate of −6.5 °C (-11.7 °F) per km (roughly −2 °C (-3.6 °F) per 1,000 ft), the table interpolates to the standard mean sea level values of 15 °C (59 °F) temperature, 101,325 pascals (14.6959 psi) (1 atm) pressure, and a density of 1.2250 kilograms per cubic meter (0.07647 lb/cu ft).
These figures should be compared with the temperature and density of Earth's atmosphere plotted at NRLMSISE-00, which shows the air density dropping from 1200 g/m 3 at sea level to 0.125 g/m 3 at 70 km, a factor of 9600, indicating an average scale height of 70 / ln(9600) = 7.64 km, consistent with the indicated average air temperature over ...
The 0 °C isotherm under normal conditions. The freezing level, or 0 °C (zero-degree) isotherm, represents the altitude in which the temperature is at 0 °C (the freezing point of water) in a free atmosphere (i.e. allowing reflection of the sun by snow, icing conditions, etc.).
Montane level: [7] [22] Extends from the mid-elevation forests to the tree line. The exact level of the tree line varies with local climate, but typically the tree line is found where mean monthly soil temperatures never exceed 10.0 degrees C and the mean annual soil temperatures are around 6.7 degrees C.
Young [6] [11] distinguished several regions where different methods for calculating astronomical refraction were applicable. In the upper portion of the sky, with a zenith distance of less than 70° (or an altitude over 20°), various simple refraction formulas based on the index of refraction (and hence on the temperature, pressure, and humidity) at the observer are adequate.