Small perturbation model for active microwave Exercise 6.1 in Elachi and van Zyl

Question

Small perturbation model for active microwave Exercise 6.1 in Elachi and van Zyl Problem 2. Vegetation soil model for passive microwave The microwave temperature of a soil surface covcrcd by a vegetation canopy can be written as T = (1-p,)T_g^e^-t'+ T_e(1 - e^t') + p_tT_c(1-e^t)e^-t Where T_g and T, are the temperatures of the soil and the canopy, respectively. The subscript refers to the polarization (either horizontal or vertical - i.e. i = h or v). The optical depth rof the canopy is a function of the vegetation water content W

Explanation / Answer

The microwave region of the electromagnetic spectrum extends from 0.3 to 300 GHz (1m
to 1mm in wavelength). Active microwave sensors are generally
divided into imaging and non-imaging category. The most common form of imaging active
microwave sensors is RADAR which is a acronym for Radio Detection and Ranging. Nonimaging
microwave sensors include altimeters and scatterometers.

Passive remote sensing system record EMR that was reflected (e.g., blue, green, red, and near IR) or emitted (e.g., thermal IR) from the surface of the Earth.

I am considering the results from the ESTAR airborne instrument, from that we have

Wc= 5Kg/m^2

soil moisture estimation= 65%

soil moisture T= 0.04 gm/cm^3

b= 0.1, T=70 K

optical depth of a canopy T= bWc= 0.1*5= 0.5

T = Ta(1-pi*e^-2t)

Ta= 70/(1-(0.1*e^(-2*0.5))) = 70/1= 70K

the 5% change in dielectic constant don't give any change in microwave temprature.

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.