<p>Short answer: yes.</p>

<p>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.</p>

<p>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).</p>

<p>The bands for TM and ETM+ are as follows:</p>

<p><a href="https://i.sstatic.net/32D4C.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/32D4C.png" alt="enter image description here"></a></p>

<p><a href="https://i.sstatic.net/M6LjF.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/M6LjF.png" alt="enter image description here"></a></p>

<p>(taken from <a href="https://landsat.usgs.gov/what-are-band-designations-landsat-satellites" rel="nofollow noreferrer">USGS Landsat Mission</a>)</p>

<p>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:</p>

<p><a href="https://i.sstatic.net/gMIiO.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/gMIiO.png" alt="enter image description here"></a></p>

<p>(Taken from USGS Q&amp;A "<a href="https://landsat.usgs.gov/esun" rel="nofollow noreferrer">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?</a>")</p>

CC BY-SA 4.0
2018-11-05T16:07:56.090Z
Thanks Camilo! After I posted the question I found this article (https://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?
Chayan Lahiri
CC BY-SA 4.0
2018-11-05T16:14:45.697Z
Hi, no problem.
Help for what? What kind of analysis are you doing with the images?
Camilo Rada
CC BY-SA 4.0
2018-11-05T17:13:46.973Z
NDVI analysis for a growing season in a oxbow lake in Mississippi. Thus there are very small elevation  changes at the site.
Chayan Lahiri
CC BY-SA 4.0
2018-11-05T17:31:36.347Z
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.
Camilo Rada
CC BY-SA 4.0
2018-11-05T17:38:56.817Z
Would sun angle matter or cause a difference if the images are taken in three months of the summer at 33 degrees north latitude?
Chayan Lahiri
CC BY-SA 4.0
2018-11-05T17:50:34.873Z
The only variable in the correction is solar elevation, therefore, the correction would not change the outcome of comparing images taken at the same solar elevation. But in three months the solar elevation can vary quite a bit, making the correction important when comparing absolute NDVI values.
Camilo Rada
CC BY-SA 4.0
2018-11-05T11:16:59.943Z
2018-11-05T11:26:04.747Z
2018-11-05T11:26:04.747Z
Camilo Rada
<p>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?</p>

<p><a href="https://landsat.usgs.gov/sites/default/files/documents/LSDS-1927_L7_Data_Users_Handbook.pdf" rel="nofollow noreferrer">Landsat 7 User Handbook</a></p>

<satellites>
Landsat 5 DN's to Top of Atmosphere reflectance
Chayan Lahiri
# Landsat 5 DN's to Top of Atmosphere reflectance

(Asked by: username_0 on 2018-11-03)

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](https://landsat.usgs.gov/sites/default/files/documents/LSDS-1927_L7_Data_Users_Handbook.pdf)

**Tags:** satellites


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## 1 answers

### Answer by username_1 on 2018-11-05. Score: 1 | Accepted answer

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](https://i.sstatic.net/32D4C.png)](https://i.sstatic.net/32D4C.png)

[![enter image description here](https://i.sstatic.net/M6LjF.png)](https://i.sstatic.net/M6LjF.png)

(taken from [USGS Landsat Mission](https://landsat.usgs.gov/what-are-band-designations-landsat-satellites))

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](https://i.sstatic.net/gMIiO.png)](https://i.sstatic.net/gMIiO.png)

(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?](https://landsat.usgs.gov/esun)")

> **Comments:**
> **username_0**: Thanks username_1! After I posted the question I found this article (https://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?  
> **username_1**: Hi, no problem. Help for what? What kind of analysis are you doing with the images?  
> **username_0**: NDVI analysis for a growing season in a oxbow lake in Mississippi. Thus there are very small elevation  changes at the site.  
> **username_1**: 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.  
> **username_0**: Would sun angle matter or cause a difference if the images are taken in three months of the summer at 33 degrees north latitude?  
> **username_1**: The only variable in the correction is solar elevation, therefore, the correction would not change the outcome of comparing images taken at the same solar elevation. But in three months the solar elevation can vary quite a bit, making the correction important when comparing absolute NDVI values.  

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