I have this paper. In equation 2 they are calculating surface emissivity. I want to ask what is 𝑷v plant proportion?


𝛆 = 𝜺𝝂*𝑷𝝂* 𝑹𝝂 +𝜺𝒔 [𝟏 −𝑷𝝂] 𝑹𝒔 +𝒅𝜺
 𝑷𝝂 is the vegetation proportion in a pixel

Was it calculated from NDVI?


Based on the article:

Land surface emissivity was calculated using the NDVI threshold method [38] suggested by Beck et al. [42]. The assumption is that bare has a NDVI < 0.2 [42]. The land surface is considered to be completely covered by vegetation if NDVI > 0.5 [42]. When the NDVI values are between 0.1 and 0.5 (0.1 ≤ NDVI ≤ 0.5), the land surface is considered to be covered by vegetation and bare soil mixing.

As such, P_v is 0 at NDVI < 0.2, 1 at >0.5 and scaled inbetween (on a related note, the values used in this article were chosen for their location. Your location may require different values).

Calculating such a 'fractional vegetation cover' map is done using a linear regression and a raster calculator.

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