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Re: Remote Sensing C

Posted: February 26th, 2017, 4:15 pm
by Skink
Thanks. I always get a little nervous that Web sites leave out this or that (not that textbooks don't--far from it--but they tend toward "completion" more than short academic Web pages do), but I can't argue with your results. I'll give it a try. I don't really have time to read another book now, anyway.

Re: Remote Sensing C

Posted: February 28th, 2017, 2:10 pm
by haverstall
hyper-specific, esoteric details.
cough MIT cough (the satellite, exact altitude of the satellite, and swath width of ASTER?)
This is really funny to me as the testwriter is a personal friend. I would say test writers are influenced by tests that they've taken before, so some writers (myself included) will have questions like that because we were similarly expected to know that information when we competed. Sometimes, those hyper-specific esoteric details are what help us separate scores. We don't necessarily want to have questions like that, but we realize some people who don't take the event seriously just won't have that information.

Re: Remote Sensing C

Posted: March 1st, 2017, 5:42 am
by JonNykiel
Has anyone found any useful textbooks for this event? The only free one I've managed to find is http://www.gdmc.nl/oosterom/PoRSHyperlinked.pdf but most of the information in here is irrelevant. In particular, I'm looking for a book that covers more of the ecology behind remote sensing and less of the physics. Thanks!

Re: Remote Sensing C

Posted: March 1st, 2017, 7:50 am
by Xuax
Has anyone found any useful textbooks for this event? The only free one I've managed to find is http://www.gdmc.nl/oosterom/PoRSHyperlinked.pdf but most of the information in here is irrelevant. In particular, I'm looking for a book that covers more of the ecology behind remote sensing and less of the physics. Thanks!
You don't really need textbooks. If you want information about the ecology and climate change aspect, watching climate science lectures is very helpful, such as https://www.youtube.com/watch?v=pdlUSCsdqB0.

Re: Remote Sensing C

Posted: March 2nd, 2017, 5:55 am
by hearthstone224
Hey guys, I got a question for you all...

There is an atmospheric window that permits transmission of EM energy in the following range:

a) 0.001 to 0.01 micrometers
b) 0.01 to 0.1 micrometers
c) 5 to 8 micrometers
d) 8 to 14 micrometers
e) 100 to 800 micrometers.

Apparently the answer is C, however I think it is D because of transmission window graphs that I find all over the internet. Why is it C? Did they grade wrong?

Re: Remote Sensing C

Posted: March 2nd, 2017, 6:01 am
by Unome
Hey guys, I got a question for you all...

There is an atmospheric window that permits transmission of EM energy in the following range:

a) 0.001 to 0.01 micrometers
b) 0.01 to 0.1 micrometers
c) 5 to 8 micrometers
d) 8 to 14 micrometers
e) 100 to 800 micrometers.

Apparently the answer is C, however I think it is D because of transmission window graphs that I find all over the internet. Why is it C? Did they grade wrong?
Try using smaller scale graphs, such as this one of the infrared info, which is what is in that wavelength.

Re: Remote Sensing C

Posted: March 2nd, 2017, 6:56 am
by hearthstone224
Hey guys, I got a question for you all...

There is an atmospheric window that permits transmission of EM energy in the following range:

a) 0.001 to 0.01 micrometers
b) 0.01 to 0.1 micrometers
c) 5 to 8 micrometers
d) 8 to 14 micrometers
e) 100 to 800 micrometers.

Apparently the answer is C, however I think it is D because of transmission window graphs that I find all over the internet. Why is it C? Did they grade wrong?
Try using smaller scale graphs, such as this one of the infrared info, which is what is in that wavelength.
Even with that though, isn't the answer 8 to 14? It's clearly not 5 to 8. I think they made a mistake.

Re: Remote Sensing C

Posted: March 2nd, 2017, 6:57 am
by Unome
Hey guys, I got a question for you all...

There is an atmospheric window that permits transmission of EM energy in the following range:

a) 0.001 to 0.01 micrometers
b) 0.01 to 0.1 micrometers
c) 5 to 8 micrometers
d) 8 to 14 micrometers
e) 100 to 800 micrometers.

Apparently the answer is C, however I think it is D because of transmission window graphs that I find all over the internet. Why is it C? Did they grade wrong?
Try using smaller scale graphs, such as this one of the infrared info, which is what is in that wavelength.
Even with that though, isn't the answer 8 to 14? It's clearly not 5 to 8. I think they made a mistake.
Unless I'm reading the graph wrong, there's clearly a gap with very little to no absorption between 5-8 micrometers.

Re: Remote Sensing C

Posted: March 2nd, 2017, 7:08 am
by jonboyage
Try using smaller scale graphs, such as this one of the infrared info, which is what is in that wavelength.
Even with that though, isn't the answer 8 to 14? It's clearly not 5 to 8. I think they made a mistake.
Unless I'm reading the graph wrong, there's clearly a gap with very little to no absorption between 5-8 micrometers.
An atmospheric window involves little to no absorption. It lets a lot of the IR through, hence "window."

Edit: it actually depends on what the vertical axis is labeled as (absorption or transmission), but we can't see in this one. I automatically assumed it was absorption because of the words "absorbing molecule" on the bottom, but it may very well be transmission. If it is transmission, then you're correct. If it is absorption, then Unome is correct.

Re: Remote Sensing C

Posted: March 2nd, 2017, 9:05 am
by hearthstone224
Alright. I don't wanna make a huge deal of this (and thanks for your help guys) but here's the image I'm looking at. I think its transmission

https://upload.wikimedia.org/wikipedia/ ... edning.png

Hopefully it shows up. Anyways, thanks for your help!

Re: Remote Sensing C

Posted: March 2nd, 2017, 9:15 am
by jonboyage
Alright. I don't wanna make a huge deal of this (and thanks for your help guys) but here's the image I'm looking at. I think its transmission

https://upload.wikimedia.org/wikipedia/ ... edning.png

Hopefully it shows up. Anyways, thanks for your help!
Yes, in that case, you're correct. The atmospheric window is present between 8 and 14 micrometers. The test maker probably saw this same image and misinterpreted it.

Re: Remote Sensing C

Posted: March 2nd, 2017, 8:12 pm
by Xuax
One unit of spectral radiance is W⋅sr^-1⋅m^-2⋅Hz^-1. Wouldn't this just simplify to J⋅sr^-1⋅m^-2? Hz^-1 is the same as seconds, and W⋅s is a joule. Am I missing something?

Re: Remote Sensing C

Posted: March 5th, 2017, 2:00 pm
by hearthstone224
Sorry Xuax, cannot help you with that question. I'm very confused on that concept in general.

However everyone I have another question:

In a well mixed column of gas, the temperature is

A) The same throughout
B) Highest at the top
C) Highest at the bottom
D) Highest in the middle
E) Stratified in vertical layers in accordance with Bernoulli's laws governing turbulent flow.

The answer is C. Why does this make sense? I don't get it. Thanks!

Re: Remote Sensing C

Posted: March 5th, 2017, 2:02 pm
by Unome
Sorry Xuax, cannot help you with that question. I'm very confused on that concept in general.

However everyone I have another question:

In a well mixed column of gas, the temperature is

A) The same throughout
B) Highest at the top
C) Highest at the bottom
D) Highest in the middle
E) Stratified in vertical layers in accordance with Bernoulli's laws governing turbulent flow.

The answer is C. Why does this make sense? I don't get it. Thanks!
I guess it's talking about the pressure (and hence temperature) increasing toward the bottom? Not sure.

Re: Remote Sensing C

Posted: March 5th, 2017, 2:06 pm
by hearthstone224
Oh, since P1V1=P2V2 and since at the bottom pressure is highest, then we know the temp would be lower?? Shouldn't it be the other way around then?

Interesting idea.