MODIS L1 to L2

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avmehta
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MODIS L1 to L2

by avmehta » Wed Jun 09, 2021 2:57 pm America/New_York

Hello,
I am processing MODIS L1 to L2 for years 2002 to 2021. I find that in each year, L1 data for several days are missing - more in some years than others. For example, 2003 has only one day missing but 2004 and 2011 have ~10 to 15 days missing. The largest number of days missing are in 2019 (~80)! Is this possible? Has this been noted by anyone?
Thank you.
Amita

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OB.DAAC - SeanBailey
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Re: MODIS L1 to L2

by OB.DAAC - SeanBailey » Wed Jun 09, 2021 4:08 pm America/New_York

Please provide the dates and region of interest. In general, there are days, or portions of days for which the sensor was not collecting data for one reason or another. If you can provide more information about the specifics of the data you believe to be missing, we may be able to provide an explanation.

Sean

avmehta
Posts: 165
Joined: Mon Feb 03, 2020 10:27 am America/New_York

Re: MODIS L1 to L2

by avmehta » Wed Jun 09, 2021 10:59 pm America/New_York

Hi Sean,
For 2019 missing days are:
005 006 015 016 021 022 027 031 032 036 043 044 052 057 060 073 081 082 085 087 088 093 109 113 114 117 119 125 130 133 134 135 136 141 151 152 158 164 174 177 178 180 182 185 205 210 213 215 216 221 228 231 232 236 238 244 254 257 258 269 270 273 274 277 279 281 287 288 296 299 313 319 325 335 336 347 351 352

I use bulk download after ordering all the swaths for one year. I did not get L1A files for these days.
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Another issue I see is that I have GEO files but then do not get L1B files. There are extra files for example, with .pcf
A2020365173000.GEO A2020365173000.GEO.pcf

There is a long LogStatus file for this file that I have attached.
Thank you for your help.
Amita
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LogStatus.A2020365173000.pdf
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OB.DAAC - SeanBailey
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Re: MODIS L1 to L2

by OB.DAAC - SeanBailey » Thu Jun 10, 2021 10:42 am America/New_York

Kinda need to know where you're looking...Is your region of interest still the Chesapeake Bay?
If so, I just ran a query using the L1/2 browser and for 2003 there were 512 granules that matched. 2019 there were 509 granules that matched. That doesn't jive with your report of 80 missing days.
In fact, spot checking the days you report against what gets returned shows they are not missing.

Please keep your posts to a single topic. The geolocation issue should be reported separately, but it looks like a case of incorrect or incomplete ephemeris data.

Sean

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