Mathematical GEOG LESSON
During the last intriguing geography lesson, we learnt that our system is capable of balancing the amount of energy that enters Earth and the amount of energy that leaves Earth. We were given a task of calculating how the amounts balance up and it became mathematical.
The energy coming into Earth is from the Sun's short wave radiation.
Most of the sun's energy [100units] goes into the surface of Earth [51units], and the rest is either reflected back into space via Earth's albedo (reflected by: back scattering [6 units], clouds [20 units] and the Earth's surface itself [4 units]), or scattered at the atmosphere (which harbours clouds, aerosols [17 units] and the ozone layer [2 units]).
Earth's surface releases long wave radiation into the atmosphere via latent heat transfer [23 units], sensible heat transfer [7 units] and mostly emissions of long wave radiation [111units]. Earth's surface also emits long wave radiation directly into space [6 units].
The atmosphere emits long wave radiation directly into space [64 units], but most of it is absorbed into Earth's surface [96 units] by diffused and direct insolation and transferred into heat energy to be used by us.
The amount of long wave radiation that goes directly back into space from the Earth's surface and atmosphere, is equals to the amount of short wave radiation that goes into the Earth's surface and atmosphere from the sun.
The amount of radiation the atmosphere receives from the Sun's radiation and from Earth's surface, is equals to the amount of long wave radiation the atmosphere gives out into space and into Earth's surface.
This is very insightful as it shows that our system is able to naturally balance all its natural heat exchanges due to negative feedback that negates change (see last post), so the number of units of heat exchange between space, the atmosphere and earth's surface will change accordingly when more heat is produced at earth's surface due to human activities (produce greenhouse gases that traps heat in the atmosphere). But due to excessive human activities, global warming results because the planetary energy balance system is too overwhelmed to tip the system back into equilibrium through negative feedback. The result, earth gets warmer and warmer.
Huimin! :P
This comment has been removed by the author.
ReplyDeleteSorry I had to delete previous comment because of some spelling mistakes.
ReplyDeleteYes, I never really knew heat absorption and radiation was studied in such a way. But I think this way of understanding it is indeed really insightful and I managed to understand why heat is being retained on the Earth in a more clear manner. And I've learnt that ITS ALL BECAUSE OF THE GREENHOUSE GASES! It is because of these gases, the whole absorption and radiation cycle takes a slower time to occur, leaving us barbequed in the heat and relying MORE on a/c systems WHICH ALSO CONTRIBUTES TO THE INCREASING WARMTH FELT BY US ON EARTH. Its just getting worse. And I want to help reduce climate change. I dont want us to die of heat. Its such a uncool thing to die of.
I agree that the geography lesson on planetary heat balance was truly insightful as it gave me a clearer understanding of how our planet balances the amount of heat we receive from the sun by various processes perfectly. HOWEVER, man is affecting the planetary heat balance as we reduce heat loss. And this reduced heat loss is in turn caused by the greenhouse gases in our atmosphere. Thus, this lesson also taught us how SYSTEMS are all INTERLINKED and CONNECTED. When we cause an imbalance to a system - the carbon cycle, we cause an impact on another - planetary heat balance. Therefore, carbon dioxide emissions is an extremely serious problem as it does not solely affect the carbon cycle but various other systems as well as systems are all CONNECTED.
ReplyDelete