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d = run Δh = rise l = slope length α = angle of inclination. The grade (US) or gradient (UK) (also called stepth, slope, incline, mainfall, pitch or rise) of a physical feature, landform or constructed line is either the elevation angle of that surface to the horizontal or its tangent.
Both an increase in the temperature and a decrease in the atmospheric pressure, and, to a much lesser degree, an increase in the humidity, will cause an increase in the density altitude. In hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.
It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the sun’s rays and a horizontal plane. [1] [2] At solar noon, the zenith angle is at a minimum and is equal to latitude minus solar declination angle. This is the basis by which ancient mariners navigated the oceans. [3]
This will give the altitude of the cloud base in feet above ground level. Put in a simpler way, 400 feet for every 1°C dew point spread. For metric divide the spread in °C by 8 and multiply by 1000 and get the cloud base in meters. Add the results from step (2) to the field elevation to obtain the altitude of the cloud base above mean sea level.
Height above mean sea level is a measure of a location's vertical distance (height, elevation or altitude) in reference to a vertical datum based on a historic mean sea level. In geodesy, it is formalized as orthometric height. The zero level varies in different countries due to different reference points and historic measurement periods.
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).
Altitude (alt. or altitude angle [b]), sometimes referred to as elevation (el. or elevation angle [c]) or apparent height, is the angle between the object and the observer's local horizon. For visible objects, it is an angle between 0° and 90°. [d]
Stream gradient may change along the stream course. An average gradient can be defined, known as the relief ratio, which gives the average drop in elevation per unit length of river. [4] The calculation is the difference in elevation between the river's source and the river terminus (confluence or mouth) divided by the total length of the river ...