Forum

Perhaps in the future we may be able to vertically resolve phytoplankton using
LIDAR from space.

See advance number 1 under the Satellite section of this paper.
https://doi.org/10.3389/fmars.2019.00251

Norman

Hi Fabrizio,I looked at a couple of your images, and the moiré patterns indicate that thechosen search radius passed to nearneighbor is too small for the spacing ofthe projected input data.  A couple of possibilities spring to mind.(a) I am not familiar with R.  Are you sure that your Rscr...

Hi Armin,

I have generally found the geolocation provided by the orthorectified
Landsat 8 data from USGS to be pretty good.  I would suspect the
land mask you are using is the problem.  The l2gen software does not
change the original projection supplied by USGS.

Norman

Hi Armin,For Landsat, I would suggest that you not use the land-mask that comes along withl2gen; it is just not of high enough resolution or accuracy.  When I need to discriminatebetween land and water in Landsat 8 data, I like to compute rhos_865 from Band 5and choose a threshold reflectance t...

Hi Eligio,Compression ratio will vary depending on the contents of the scene.L2 scenes that have large areas masked out (e.g. for land) willcompress much smaller than those with a more complete andvarying feature set.If I were you, I would set up a processing flow that downloadsscenes serially and d...

Hi Eligio,You can get daily level-2 volumes by adding up the file sizes in bytesfrom pages like this representative Aqua/MODIS page from yesterday.https://oceandata.sci.gsfc.nasa.gov. (/MODIS-Aqua/L2/2020/078/). If you are only interested in coastal regions, you will obviously haveless data to proce...

In addition to heavy suspended sediment load in the Bay of Bengal,the region also suffers from perennially bad air quality.  This negativelyaffects the accuracy of the MODIS atmospheric correction.I am afraid your reviewers are correct.  Ocean color remote sensingis difficult even over cle...

Hi Robert,I've been having some hallway conversations with folks whoknow a lot more about how our sausage is made than I do.The general thinking is that MODIS instrument calibrationis a never-ending process as the aging spacecraft is exposedto the ever changing space environment.  As one ge...

Hi Robert,I was a bit more careful this time, and I do see what you are seeing.The following three images show differences between subsequent8-day 9km composites of adg_443_giop.  Red indicates that adg isgreater in the minuend, while blue shows areas where adg is greaterin the subtrahend. Whit...

Um, strike that image.  I just realized I didn't leave out the "no data" areas.
I'll have another look at this tomorrow, but if you could provide any additional
details in the mean time, that might help make sure I am looking in the
right place.

Norman