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The landsat 7 etm+ users handbook does the the Dn to top atmosphere correction (pages 79-80, link below). Is this applicable to landsat 5 tm as well?

Landsat 7 User Handbook

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Short answer: yes.

The Radiance to Reflectance correction described in the Handbook is just physics based. Therefore, it is valid for any Earth observing satellite. However, the mean solar exo-atmospheric irradiances (table 5-2) are specific to the wavelength bands of the ETM+ sensor. Therefore, if you want to correct other bands you would need new coefficients valid for the corresponding wavelength range.

But in the case of Landsat 5 and 7, the bands are almost identical (with very small differences on bands 4 and 7). Therefore, unless you need very high accuracy I would say that it is safe to use ETM+ coefficient (Landsat 7) to correct TM imagery (Landsat 4 and 5).

The bands for TM and ETM+ are as follows:

enter image description here

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(taken from USGS Landsat Mission)

Note that it is not only the boundaries of the bands what matter, but also the spectral response within the band. Therefore, even for bands that seem identical, the coefficients of exo-atmospheric irradiances can present small differences. Ideally, you should use the coefficients calculated specifically for the TM sensor, but using the ETM+ values would provide a very good approximation. At least good enough for most applications. But if you want to use the TM specific values, they are as follows:

enter image description here

(Taken from USGS Q&A "Where can I find the solar exoatmospheric spectral irradiances (ESUN) for the Landsat 1-5 MSS, Landsat 4-5 TM, and Landsat 7 ETM+ sensors?")

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  • $\begingroup$ Thanks Camilo! After I posted the question I found this article (ntrs.nasa.gov/search.jsp?R=20090027884), the tables at the end of the article have different slightly different numbers. What do you think? And a follow up question. It would probably depend on a case to case basis to the best of my understanding. But does it help to use surface reflectances over TOA reflectance? What do you think? $\endgroup$ – Chayan Lahiri Nov 5 '18 at 16:07
  • $\begingroup$ Hi, no problem. Help for what? What kind of analysis are you doing with the images? $\endgroup$ – Camilo Rada Nov 5 '18 at 16:14
  • $\begingroup$ NDVI analysis for a growing season in a oxbow lake in Mississippi. Thus there are very small elevation changes at the site. $\endgroup$ – Chayan Lahiri Nov 5 '18 at 17:13
  • $\begingroup$ Using surface reflectances instead of TOA would be important if you are comparing absolute NDVI values between different images. And even more important if the images to be compared are from significantly different DOY (Day Of Year), that means different solar elevations. For this and your previous question remember to accept the answers if you find them satisfactory. $\endgroup$ – Camilo Rada Nov 5 '18 at 17:31
  • $\begingroup$ Would sun angle matter or cause a difference if the images are taken in three months of the summer at 33 degrees north latitude? $\endgroup$ – Chayan Lahiri Nov 5 '18 at 17:38

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