Hello ocean colour folks,
I have been making 1 km SST layers by downloading night-time MODIS-Aqua L2 SST images, and binning / mapping into composites with SeaDAS.
However the non-uniformity flags result in valid pixels along SST fronts and gradients being removed. This removes quite a lot of data in my region (Pacific North America) especially during summer. Some example images are attached below.
I have been using the "best quality" option in l2bin (qual_max = 0) and experimenting with other quality levels doesn't make much of a difference. Is there a recommended method that I could try to reduce this effect? E.g.
- This appears most pronounced with night-time data, it might be worth just using day-time data instead?
- Perhaps it's worth switching to VIIRS for more recent years / merging it with the MODISA SST?
- Instead of downloading L2 I could process from L1A - are there SeaDAS settings recommended to reduce or mitigate this issue?
The code I'm using to bin and map is below.
Thanks very much,
-Andrea
I have been making 1 km SST layers by downloading night-time MODIS-Aqua L2 SST images, and binning / mapping into composites with SeaDAS.
However the non-uniformity flags result in valid pixels along SST fronts and gradients being removed. This removes quite a lot of data in my region (Pacific North America) especially during summer. Some example images are attached below.
I have been using the "best quality" option in l2bin (qual_max = 0) and experimenting with other quality levels doesn't make much of a difference. Is there a recommended method that I could try to reduce this effect? E.g.
- This appears most pronounced with night-time data, it might be worth just using day-time data instead?
- Perhaps it's worth switching to VIIRS for more recent years / merging it with the MODISA SST?
- Instead of downloading L2 I could process from L1A - are there SeaDAS settings recommended to reduce or mitigate this issue?
The code I'm using to bin and map is below.
Thanks very much,
-Andrea
Code:
yr=$1L2BIN_RES="1" L3MAP_RES="1km"l2_suffix="L2.SST.nc"north=56.5south=46east=-122west=-139.5months=$(seq 1 1 12)days=$(seq 1 1 31)for month in $months; do for day in $days; do m=`echo $month | awk '{printf("%02d", $1)}'`; d=`echo $day | awk '{printf("%02d", $1)}'`; echo $m $d;if compgen -G "*${yr}${m}${d}*$l2_suffix" > /dev/null; then# l2binls *${yr}${m}${d}*$l2_suffix > tmp_l2bin.txt; l2bin ifile=tmp_l2bin.txt ofile=AQUA_MODIS.${yr}${m}${d}.L3b_NSST.nc l3bprod=sst resolution=$L2BIN_RES night=1 qual_prod=qual_sst qual_max=0 suite=NSST; # l3binl3bin ifile=AQUA_MODIS.${yr}${m}${d}.L3b_NSST.nc ofile=AQUA_MODIS.${yr}${m}${d}.L3b_NSST.x.nc prod="sst" latnorth=$north latsouth=$south loneast=$east lonwest=$west;# L3mapl3mapgen ifile=AQUA_MODIS.${yr}${m}${d}.L3b_NSST.x.nc ofile=AQUA_MODIS.${yr}${m}${d}.L3m_NSST.x.nc resolution=$L3MAP_RES product="sst" north=$north south=$south east=$east west=$west interp=area projection="+proj=aea +lat_0=45 +lon_0=-126 +lat_1=50 +lat_2=58.5 +x_0=1000000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs";# Make .pngINFILE=AQUA_MODIS.${yr}${m}${d}.L3b_NSST.x.ncl3mapgen ifile=$INFILE ofile=${INFILE:0:-3}.png oformat=png resolution="1km" product="sst" apply_pal=yes scale_type=linear mask_land=yes north=$north south=$south east=$east west=$west interp=area datamin=-1.89 threshold=1.0 full_latlon=no datamax=30 projection="+proj=aea +lat_0=45 +lon_0=-126 +lat_1=50 +lat_2=58.5 +x_0=1000000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs"fi done doneStatistics: Posted by schckngs — Tue Apr 16, 2024 1:48 pm America/New_York