NIFE Weather Questions and Answers Already Passed

NIFE Weather Questions and Answers Already Passed What is the composition of dry air? 78% nitrogen 21% oxygen 1% mixture of 10 other gases How much of the atmosphere, by volume, is composed of water? 0 to 5% What are condensation nuclei? -Nongaseous substances such as dust and salt particles, pollen, etc -Water molecules condense on these particles and form clouds What layer of the atmosphere is adjacent to the Earth's surface? Troposphere List some characteristics of the troposphere. -Adjacent to Earth's surface -Average height of 36,000'MSL above the US -Becomes less dense with altitude -Temperature decreases with increasing altitude -Nearly all weather occurs here -Wind velocity increases with altitude What is the tropopause and where is it found? -Transition zone between the troposphere and stratosphere -Temperature is constant with altitude -Jet stream occurs right below (strongest winds) Define Atmospheric Pressure (Barometric Pressure) -Pressure exerted on a surface by the atmosphere due to the weight of the column of air directly above that surface -Pressure always decreases with altitude (decreases more rapidly at lower altitudes because of decreasing density) What are the two units of measurement for atmospheric pressure? -in-Hg: measure of the height of a column of mercury that can be supported by atmospheric pressure -Millibar: direct representation of pressure (force/unit area) -Normal sea level pressures range from 28-31 in-Hg (960-1060mb) Surface analysis charts use _______ as the reference pressure level for isobars. -MSL barometric pressure (to provide a common reference) -Allows meteorologists to track weather systems as they move across the country What type of vertical atmospheric circulation is associated with a high-pressure system? Air will descend (downward force exerted by high pressure) and diverge, which produces wind What type of vertical atmospheric circulation is associated with a low-pressure system? Air will ascend (insufficient pressure to keep air at the surface) and try to converge at the center of the low-pressure, which also produces wind What effect does the Coriolis Force have on wind as it moves horizontally into/out of high/low pressure systems? -Wind will circulate as it moves out of a High-pressure system and into a Low-pressure system -Clockwise out of a high-pressure system (in the northern hemisphere) -Counterclockwise into a low-pressure system