What happens to the temperature of a descending air mass?
The orographic effect occurs when air masses are forced to flow over high topography. As air rises over mountains, it cools and water vapor condenses. However, there is no source of additional water, so the descending air mass increases in temperature but the amount of water vapor remains constant.
Does a descending air mass warm or cool?
Now, ascending air cools, and cool air is able to hold less moisture than warm air. Thus, convective storms form readily under the rising branch of the Hadley cell. Conversely, descending air (whether at subtropical or polar latitudes) both dynamically suppresses convection and warms, as the graphic below shows.
How does air mass affect climate?
When winds move air masses, they carry their weather conditions (heat or cold, dry or moist) from the source region to a new region. When the air mass reaches a new region, it might clash with another air mass that has a different temperature and humidity. This can create a severe storm.
What happens when air rises in the troposphere?
Air is warmest at the bottom of the troposphere near ground level. Air gets colder as one rises through the troposphere. That’s why the peaks of tall mountains can be snow-covered even in the summertime. Air pressure and the density of the air also decrease with altitude.
What is a descending air mass?
A descending air mass is drier because the air becomes warmer as it moves down in the atmosphere. Therefore, the humidity in the air mass decreases as…
When does the density of air increase or decrease?
Density will increase if either mass increases while the volume remains constant or if volume decreases while mass remains constant. Density of air will vary as the temperature and moisture content in the air varies.
Why is moist air less dense than dry air at same temperature?
Oxygen (32 units) and diatomic Nitrogen (28 units). Thus at a constant temperature, the more water vapor that displaces the other gases, the less dense that air will become. You may be familiar with the concept that moist air is less dense than dry air. This is true when both have
How are the properties of an air mass determined?
• Air masses have fairly uniform temperature and moisture content in horizontal direction (but not uniform in vertical). • Air masses are characterized by their temperature and humidity properties. • The properties of air masses are determined by the underlying surface properties where they originate.
Where do polar and MP air masses form?
• Maritime polar air masses form over upppp ger latitude oceanic regions and are cool and moist. • mP air masses form over high-latitude ocean as cP air masses move out from the interior of continents. (i.e., cP ÆmP). • Oceans add heat and moisture into the dry and cold cP air masses.