MSL data in the PDS and the Analyst's Notebook, Working with the archived science & engineering data |
MSL data in the PDS and the Analyst's Notebook, Working with the archived science & engineering data |
Feb 27 2013, 07:22 PM
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Solar System Cartographer Group: Members Posts: 10229 Joined: 5-April 05 From: Canada Member No.: 227 |
"February 27, 2013. MSL Release 1, part 1, Sols 0-89.
The first release of MSL data takes place in two parts. Part 1, February 27, 2013, includes raw data products (EDRs) acquired on Sols 0 through 89, August 6 through November 5, 2012, for these instruments: APXS, ChemCam, DAN, Hazcam, Navcam, and REMS, along with SPICE data. Part 2, March 20, 2013, will include the derived data products (RDRs) for Sols 0 though 89 for the APXS, ChemCam, DAN, Hazcam, Navcam, and REMS instruments, along with both the EDRs and RDRs for the CheMin and RAD instruments, and the RDRs for the SAM instrument. Release 1 does not include data from the MAHLI, MARDI, or Mastcam instruments. These instrument teams have not yet delivered data products to PDS. Some documents in the MSL archives are awaiting clearance by JPL Document Review and/or the JPL Import/Export Control Office. They will be posted online as soon as clearance has been received, and announced on this web site." Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Mar 29 2013, 02:42 PM
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Planck's function isn't linear, and it's dependent of the absolute temperature. So it should be possible to infere the absolute temperature from the brightness temperatures at two known wavelengths and two different temperatures...
Under ideal conditions, in theory. Before doing theory in detail, I first checked the data to find out, whether it can work in practice. The intermediate answer is: Not in a straightforward way. Emissivity seems to change with time, and in a different way for the two frequency bands A and B. The first reason I could isolate is warm-up. Here some statistical analysis of 18 warm-ups on sol 89 for brightness temperature A, based on this Sol 89 REMS RDR file: The first diagram shows brightness temperature A for the first 100 seconds of 18 warm-ups, adjusted by average and stretched by respective standard deviations. The second diagram averages over these 18 curves. The third diagram smoothes the latter curve by averaging over a window of 10 seconds. It shows a significant average increase of brightness temperature A during warm-up. So a first step to get better data, will be to apply the last column (column 63) of the referenced table, indicating warm-up, not just to pressure data as described in this FMT file, but also to brightness temperatures. EDIT: Some number-crunching later: Radiance at 250K and 11um seems to be much less (about factor 5) sensitive to emissivity near 1 than to absolute temperature (use Planck function with 250K at 11um as brightness temperature, and divide it by the value at 255K as absolute temperature; the result is the corresponding emissivity). So an emissivity of 0.9 will lead to an absolute temperature 5K above brightness temperature (near 250K). I overestimated emissivity in the beginning. Although I didn't yet investigate, how the emissivity quotient influences measurement of absolute temperature by dividing radiances of two wavelength bands (two-colour pyrometer). |
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