Search found 284 matches

by LAADS_UserServices_M
Tue Jun 13, 2023 11:29 am America/New_York
Forum: Home
Question: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2
Replies: 9

Re: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2

Yes, you are correct.
by LAADS_UserServices_M
Mon Jun 12, 2023 11:43 am America/New_York
Forum: Home
Question: Request for Flood inundation data
Replies: 2

Re: Request for Flood inundation data

You can explore LAADS API interface to automate NRT data download. You can find information including quick start guide and API specification at: https://ladsweb.modaps.eosdis.nasa.gov/tools-and-services/#api-v2 A sample call would look like: https://nrt3.modaps.eosdis.nasa.gov/api/v2/content/archiv...
by LAADS_UserServices_M
Wed Jun 07, 2023 11:14 am America/New_York
Forum: Home
Question: Python download script utf-8 UnicodeDecodeError VNP46A1
Replies: 1

Re: Python download script utf-8 UnicodeDecodeError VNP46A1

The issue is that HDF5 is a binary format, not a text format. There is no text encoding that will work to decode it as text (as you are seeing). The script does also read csv or json files from the web site, to get the directory listings, so it needs to be able to read both text and binary data. Unf...
by LAADS_UserServices_M
Wed Jun 07, 2023 10:50 am America/New_York
Forum: Home
Question: Read the reflectance of MODIS L1B data
Replies: 3

Re: Read the reflectance of MODIS L1B data

The MOD03 file has the lat/lon and view geometry at the same resolution as the L1B file. If these fields from an L1B file are to be used an interpolation to account for the different dimensions needs to be performed.
by LAADS_UserServices_M
Mon Jun 05, 2023 9:23 am America/New_York
Forum: Home
Question: Read the reflectance of MODIS L1B data
Replies: 3

Re: Read the reflectance of MODIS L1B data

The MOD021KM files contain radiances and reflectances, What's stored in the files are HDF Scientific Data Sets (SDSs), each of which has a "long_name" attribute that ends with "Scaled Integers". The values store in those SDSs are scaled integers, (abbreviated SI). You need to use...
by LAADS_UserServices_M
Wed May 31, 2023 6:19 am America/New_York
Forum: Home
Question: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2
Replies: 9

Re: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2

We further looked into the granules to check the Aerosol Optical Depth (AOD) pattern you reported and below is the summery: The Missing Aerosol Optical Data (AOD) is not the systematic issue. ​ They are relevant to the pixel selections. For the following conditions, the AOD values will be​ fill valu...
by LAADS_UserServices_M
Tue May 30, 2023 7:57 am America/New_York
Forum: Home
Question: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2
Replies: 9

Re: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2

Also, the Dark Target AOD cannot be retrieved over brighter surfaces. So, you may be getting confused by an apparent pattern that forms over the equatorial and tropical areas, where most of the areas are brighter because of clouds and deserts, and so there is not much retrieval of DT AOD, creating o...
by LAADS_UserServices_M
Fri May 26, 2023 11:58 am America/New_York
Forum: Home
Question: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2
Replies: 9

Re: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2

Dear Laxmi: Please note the following: Have you tried to cross-reference the missing areas with the MODIS cloud mask (MxD35_L2) to see if those areas have persistent cloud. You can also reference a RGB reflectance image for this. With regard to this question: coverage of the MODIS swath keeps on cha...
by LAADS_UserServices_M
Mon May 22, 2023 11:50 am America/New_York
Forum: Home
Question: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2
Replies: 9

Re: Missing Aerosol Optical Depth (AOD) Data in MYD04_L2

Dear Laxmi:
Can you provide an example from files that exhibit such behavior (couple of file names should be sufficient)?
by LAADS_UserServices_M
Thu May 18, 2023 8:55 am America/New_York
Forum: Home
Question: VIIRS VNP46A2 timestamp acquisition time
Replies: 1

Re: VIIRS VNP46A2 timestamp acquisition time

This is because VNP46A2 is a daily products containing observation for the 24h period. You can find UTC-Time parameter in VNP46A1 product that lists UTC view time (the time of data acquisition). For more information consult product users guide at: https://ladsweb.modaps.eosdis.nasa.gov/api/v2/conten...