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Showing posts with label warming. Show all posts
Showing posts with label warming. Show all posts

Tuesday, May 17, 2016

Global Warming VS. the Greenhouse Effect

Global warming posits the questions “will an increase in concentration of greenhouse gases lead to an increased global average temperature?” Whereas, the greenhouse effect is a fact that states that the average global temperature is warmer than it would be in the absence of an atmosphere due to greenhouse gases that are being absorbed and re-radiated.

Incoming shortwave (visible light and infrared) radiation gets absorbed by the Earth thus causing the ground to heat and emit longwave (infrared) radiation. The longwave radiation, then, gets absorbed by greenhouse gases (CO2, H2O, CH4) which, in turn, heats up and re-emits radiation out in every direction (some towards the Earth). Notably the cycle continues when some of that radiation, again, gets absorbed by the ground, heats the ground even more, emits even more radiation, and so on.

Chinook, Santa Ana and Katabatic Winds

Chinook, Santa Ana and Katabatic winds are those that flow downslope in response to the distribution of high- and low-pressure systems over and near large mountain areas, where compressing of descending air leads to adiabatic warming.
Chinook winds, off the eastern slopes of the Rocky Mountains in North America, form due to air flowing across the range. Low-pressure systems east of the mountains cause strong winds to descend the eastern slopes. Although, sometimes the presence of a large mass of cold, dense air near the base of the mountain range may prevent a chinook from flowing all the way down the slope.

Santa Ana winds, contrary to what people believe, occur in response to a large area of high-pressure which descends toward lower elevations and warms by compression causing air to flow out of the Rockies, they are not warm because they pass over hot desert surfaces. When Santa Ana’s develop, the combination of hot, dry winds, low humidity, and an abundant source of fuel can set the stage for an extensive fire that destroys a great deal of land or property.


            Katabatic winds, on the other hand, originate when air is locally chilled over a high-elevation plateau, where the air becomes dense due to its low temperature and flow downslope. These very strong gusts and lulls of winds cover much of coastal Antarctica and Greenland. They also flow out of the Balkan Mountains towards the Adriatic coast, where they are called boras; whereas, in France, they flow out of the Alps into the Rhone River Valley and are called mistrals.