<p>In remote sensing you often do not directly measure the variable of interest, i.e., you measure it via some other variable that you can measure (depending on the type of instrumentation). The model function is simply the function which relates the observed variable to the variable of interest, just like y=f(x).</p>

<p>E.g., y could be wind speed, and x the energy measured by the scatterometer.</p>

CC BY-SA 3.0
2015-03-18T22:13:00.920Z
Thank you @stali for your input. However, I have seen the term GMF (geophysical model function) used in exactly the opposite fashion: y=GMF(x), where y is the observed quantity, and x is the geophysical quantity. For example, in the recent Ulaby remote sensing book, there are many examples where y is the radar scattering cross-section, and x is the windspeed, sea surface temperature, etc. Could you provide some references as examples of the usage you describe above?
user4624937
CC BY-SA 3.0
2015-03-16T16:17:59.533Z
2015-03-16T17:54:02.413Z
2015-03-16T17:54:02.413Z
stali
<p>I have heard the term mentioned many times in seminars, and in papers on remote sensing. What does it mean? References would be helpful if available. </p>

<geophysics><models><remote-sensing>
What is a Geophysical Model Function (GMF)?
user4624937
# What is a Geophysical Model Function (GMF)?

(Asked by: username_0 on 2015-03-08)

I have heard the term mentioned many times in seminars, and in papers on remote sensing. What does it mean? References would be helpful if available.

**Tags:** geophysics, models, remote-sensing


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## 1 answers

### Answer by username_1 on 2015-03-16. Score: 4

In remote sensing you often do not directly measure the variable of interest, i.e., you measure it via some other variable that you can measure (depending on the type of instrumentation). The model function is simply the function which relates the observed variable to the variable of interest, just like y=f(x).

E.g., y could be wind speed, and x the energy measured by the scatterometer.

> **Comments:**
> **username_0**: Thank you @username_1 for your input. However, I have seen the term GMF (geophysical model function) used in exactly the opposite fashion: y=GMF(x), where y is the observed quantity, and x is the geophysical quantity. For example, in the recent Ulaby remote sensing book, there are many examples where y is the radar scattering cross-section, and x is the windspeed, sea surface temperature, etc. Could you provide some references as examples of the usage you describe above?  

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