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PDS Geosciences Node Community
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      Posts relating to the 2012 MRO/CRISM Data Users' Workshop.

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  • Recent Topics

    • Mr. Singh, TB values are found in column 24 of Diviner RDR data products (column header "tb"). The channel number is located in column 18 (column header "c"). You can get TB values strictly from channel 9 by selecting only column 24 data where column 18 is equal to 9. You then can apply your formula to these values. Alternatively, Diviner GCP products have "Bolometric average calibrated brightness temperature (K)" noted in column 11, for a given longitude and latitude noted in columns 1 and 2 respectively. If you can explain what you mean by "Zonal mean temperature" I'd be happy to help you with that as well.
    • You mean emissivity of that channel ? Also, I have a question like if I want to convert TB to Bolometric temperature than how will I do that in RDR ? . I am using ArcMap. How will I convert it to bolometric brightness temperature for channel 9 only . I have the formula but don't know how to implement ?    Another question about Zonal mean temperature ? It refers to zonal mean as if for certain range of lat , long ? 
    • Some users of LRO Diviner data have asked why there are some data products with negative temperature values. For example: "I'm exploring the temperature data of the Diviner, I have downloaded TB (Brightness Temperature) data for 6,7,8, and 9 channels and I found negative values (in K) in a few of the images after conversion (TB= (DN * scaling factor) + Offset). This negative value is not possible in K, I'm unable to understand this." Answers from Diviner team members: "The shorter wavelength channels are noisy at low temperatures. Each channel has a minimum temperature below which it becomes noisy. These minimum temperature cutoffs go down with longer wavelength channels, so channels 8 and 9 are really the only ones that return useful data in the PSRs. When the channel gets below this minimum temperature, it starts returning negative radiance values. This would explain why channel 4 is giving you negative temperatures, while channel 9 does not. I've attached the Supporting Material from the Paige et al 2010 Science paper [see attachment Paige.SOM.pdf]. The table gives the minimum temperatures for the IR channels (3-9)." (Dr. Jean-Pierre Williams, UCLA, 2019-03-11) "The negative temperatures are actually "good" data. When the net signal at the detectors after calibration gets close to zero, Diviner records both small  positive and small negative radiances. When the negative radiances are turned into brightness temperatures, they are reported as brightness temperatures. Zero-ing out the negative radiances would be completely inappropriate, because it is possible to pull signal out of the noise by averaging. You should see more negative temperatures in the shorter wavelength channels (3-6), as well as all channels in the coldest places near the poles. When the thermal emission from the moon is so small that there is no measurable signal, there's a 50% probability that a small negative signal will be measured. We convert these to brightness temperatures, and flag them as negative brightness temperatures, with the understanding that negative temperatures are not possible. In isolation, you can't convert negative temperatures into meaningful temperatures.  What we generally do is pick a threshold below which all temperatures should be ignored. This will vary depending on which Diviner channel you are using." (Dr. David Paige, UCLA, 2020-03-24) Paige.SOM.pdf
    • March 20th, 2020 - LRO Release 41 has been loaded into ODE. Updated LAMP EDR and RDR products from July 6th, 2009 to December 15th, 2019 Updated LEND EDR_SCI, EDR_HK, RDR_RSCI, and RDR_CHK products from June 18th, 2009 to December 14th, 2019 Updated LEND RDR_DLD and RDR_DLX products from June 27th, 2009 to September 14th, 2019 Updated Diviner EDR and RDR products from July 5th, 2009 to December 16th, 2019 Updated LROC EDR, CDR and RDR products from June 30th, 2009 to December 3rd, 2019 Loaded Mini-RF new Version 3 Bistatic radar data products (EDR, RDR, and DDR) from January 28th, 2019 to June 13th, 2019 Updated LOLA EDR products from June 18th, 2009 to January 22nd, 2020 Updated LOLA RDR products from July 13th, 2009 to January 22nd, 2020 Updated LOLA RDR query tool database from July 13th, 2009 to January 22nd, 2020 Updated Diviner RDR query tool database from July 5th, 2009 to December 16th, 2019 Please see ODE Lunar Holdings - https://wufs.wustl.edu/ode/odeholdings/Moon_holdings.html  
    • March 19th, 2020 -    Updated MRO SHARAD EDR and RDR products from ASI for MRO Release 52 through August 17th, 2019 (orbits through 61208)
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