Remote Sensing C

[geniusjohn5]

Is there a difference between irradiance or radiant exitence or radiant flux? If so, can someone please explain?

I think radiant flux is a general term for radiation through a region, be that emitted by a surface, transmitted through the surface, reflected from the surface, etc, and radiant exitance is the radiant flux emitted by a region divided by the region's area, so to get the radiant flux emitted you would multiply by the area. Irradiance works the same way as radiant exitance - if you multiply irradiance by area you get total radiant flux - except that it's the radiant flux received, not the radiant flux emitted by the surface like radiant exitance is.

Is that followable?

Yup. I understood pretty much all of what you just said. Just one clarification: Irradiance multiplied by area = radiant flux RECEIVED and radiant exitance refers to radiant flux EMITTED?

[geniusjohn5]

Can someone explain how to do this question:

The total solar irradiance at the top of the atmosphere is 1360 W/m^2. How much solar radiation is reflected to balance the radiative energy from the atmosphere?

I misplaced my answer key so I don't even know the solution myself.

[Alex-RCHS]

Is there a difference between irradiance or radiant exitence or radiant flux? If so, can someone please explain?

I think radiant flux is a general term for radiation through a region, be that emitted by a surface, transmitted through the surface, reflected from the surface, etc, and radiant exitance is the radiant flux emitted by a region divided by the region's area, so to get the radiant flux emitted you would multiply by the area. Irradiance works the same way as radiant exitance - if you multiply irradiance by area you get total radiant flux - except that it's the radiant flux received, not the radiant flux emitted by the surface like radiant exitance is.

Is that followable?

To clarify, is radiant flux in units of Watts and radiant exitance in units of Watts/square meter?

[whythelongface]

In physics, flux refers to energy passing through a surface per unit time. Radiant flux is radiant energy passing through an object per unit time, making it equivalent, in terms of units, to power.

Irradiance and radiant exitance both refer to flux passing through areas, although irradiance refers to incoming radiant flux incident on a surface and exitance refers to radiant flux leaving a surface. Both are in standard SI units, watts per meter squared.

[geniusjohn5]

Has anyone encountered a question that asks you to label the components of a satellite? Generally, I don't think a question like this should show up on RemSen test but I just want to confirm whether or not.

[Sleepy]

What is the difference between false color imaging and pseudo color imaging? I'm not understanding the difference very well upon searching google.

[knottingpurple]

What is the difference between false color imaging and pseudo color imaging? I'm not understanding the difference very well upon searching google.

False color is you assign different bands of light to R, G, and B in an image, it's just it's not red assigned to R, green assigned to G, and blue assigned to B. One of the most common types assigns NIR, R, G to R, G, B; but you could also do it with other types of light showing up as whatever color on the image.

Pseudo color, each color represents a different value within a certain variable - so, sea surface temperature, where you have a scale from, like, blue to red, for cool to warm, this is pseudo color. Rather than it being colors assigned to red, green and blue and the colors that are assigned are not the real ones, it's basically like an image going from black to white for low values to high values, except they use color to make it easier to tell.

[sciolyPA]

I have been asked several times, including on my Regional test, how many pixels are in this image. I don't have examples of this because it was on a Regional test, but can someone explain how you are supposed to be able to tell? (All the answer choices were low numbers, but I thought there were a lot of pixels in images)

[windu34]

I have been asked several times, including on my Regional test, how many pixels are in this image. I don't have examples of this because it was on a Regional test, but can someone explain how you are supposed to be able to tell? (All the answer choices were low numbers, but I thought there were a lot of pixels in images)

Count the "squares" in the image. Some example images may just be a grid of a few squares where each square represents one pixel

[windu34]

Sign-up to compete in a nation-wide remote sensing competition! This competition IS NOT AFFILIATED WITH NATIONAL SCIENCE OLYMPIAD. The test materials will be sent to registered competitors by email, but all materials will publicly released eventually. Raw scores and rankings will be released.
The goal of this exam is for students across the nation to be able to compare their mastery of remote sensing with peers.
https://goo.gl/forms/8sOXDapoTd6xcBzL2

I will edit this post with a list of schools that are currently signed up. If you have any questions, feel free to PM me!