Earthdata Forum

Hi, I tried to process one level 1a MODIS-A image to l2 and compared the Rrs_443 with the l2 product released online by OBPG, the values are actually not the same. I wonder whether the processing parameters are not the same, and how could I generate exactly the same l2 product? Thanks!

The filename of L1A is A2007042213000.L1A_LAC, the L2 product released online is AQUA_MODIS.20070211T213002.L2.OC.nc, I attached the comparison between the L2 product released online and L2 product I reproduced (the palette and range are the same).

I process L1A to GEO and L1B through command line, then I run l2gen with GUI and use the default settings of l2gen.

The seadas software & system info are here:
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Main Application Platform:
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Application Version: SeaDAS 9.0.1
SNAP Engine Version: 11.0.0.0* (SeaDAS Platform modified)
SNAP Desktop Version: 11.0.0.0* (SeaDAS Platform modified)
SNAP Engine Build Date: 202405131445
SNAP Desktop Build Date: 202405131450
Installation Directory: /home/nkd/software/SeaDAS
Data Directory: /home/nkd/.seadas9
Configuration: /home/nkd/software/SeaDAS/etc/snap.properties
VM Configuration: /home/nkd/software/SeaDAS/etc/seadas.conf
VM Configuration: /home/nkd/software/SeaDAS/etc/snap.conf
VM Configuration (gpt): /home/nkd/software/SeaDAS/bin/gpt.vmoptions
VM Configuration (pconvert): /home/nkd/software/SeaDAS/bin/pconvert.vmoptions
Runtime Configuration: /home/nkd/.seadas9/etc/snap.properties
Runtime Configuration (SeaDAS Toolbox): /home/nkd/.seadas9/etc/seadas.properties
JRE: OpenJDK Runtime Environment 11.0.19+7
JVM: OpenJDK 64-Bit Server VM by Eclipse Adoptium
Memory: 4096 MiB
OCSSWROOT (Java Env): /home/nkd/OCSSW_V2022
Python3 Directory: /usr/bin/python3


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SeaDAS Toolbox:
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SeaDAS Toolbox Version: 2.0.0
SeaDAS Toolbox Build Date: 202405131459
Configuration: /home/nkd/.seadas9/etc/seadas.properties
OCSSW Root Directory: /home/nkd/software/SeaDAS/ocssw
OCSSW Docker Log Directory: /home/nkd/software/SeaDAS/bin
OCSSW Location: local
Environment {$OCSSWROOT} (external): /home/nkd/OCSSW_V2022
WARNING!: An environment variable for OCSSWROOT exists which does not match the GUI configuration. The GUI will use '/home/nkd/software/SeaDAS/ocssw' as the ocssw root inside the GUI.


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NASA Science Processing (OCSSW):
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Environment {$OCSSWROOT}: /home/nkd/software/SeaDAS/ocssw
Environment {$OCDATAROOT}: /home/nkd/software/SeaDAS/ocssw/share
l2gen version: msl12 9.5.1-R2022.0 (Jan 26 2022 14:41:53)
l2bin version: 7.0.3
l3bin version: 5.13
l3mapgen version: l3mapgen 2.3.0-R2022.0 (Jan 26 2022 14:43:37)
Installed Missions: ['aqua', 'terra']


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General System and Software:
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Operating system: Ubuntu 20.04.6 LTS
Java version: 1.8.0_421
Python3 version: 3.8.10
Python3 Path: /usr/bin/python3
Env: ASAP_PARMS=/home/nkd/software/SeaDAS/ocssw/share/common/nav
CC=gcc
CLASSPATH=.:/java/jdk1.8.0_421/lib:/java/jdk1.8.0_421/jre/lib:
COLORTERM=truecolor
CXX=g++
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus,guid=74084ce0ac37d61ec47a8b7a670cd483
DBUS_STARTER_ADDRESS=unix:path=/run/user/1000/bus,guid=74084ce0ac37d61ec47a8b7a670cd483
DBUS_STARTER_BUS_TYPE=session
DESKTOP_SESSION=ubuntu
DISPLAY=:0
ELEMENTS=/home/nkd/software/SeaDAS/ocssw/var/seawifs
EOS_LIB_PREFIX=linux64
FC=gfortran
GCC_TUNE=
GDK_BACKEND=x11
GDMSESSION=ubuntu
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
GNOME_SHELL_SESSION_MODE=ubuntu
GNOME_TERMINAL_SCREEN=/org/gnome/Terminal/screen/6e13b14a_eab2_4093_b37d_78410b8ce4b9
GNOME_TERMINAL_SERVICE=:1.90
GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
GTK_MODULES=
HDFEOS_LIB=/home/nkd/software/SeaDAS/ocssw/opt/EOS/lib/linux64
HOME=/home/nkd
_=/home/nkd/software/SeaDAS/ocssw/bin/seadas_info
HRPT_STATION_IDENTIFICATION_FILE=/home/nkd/software/SeaDAS/ocssw/share/seawifs/station/station_id.dat
IM_CONFIG_PHASE=1
INVOCATION_ID=767f59f6844b4b088fbccae9e1572613
J2D_PIXMAPS=shared
JAVA_HOME=/java/jdk1.8.0_421
JOURNAL_STREAM=8:49816
JRE_HOME=/java/jdk1.8.0_421/jre
L2GEN_ANC=/home/nkd/software/SeaDAS/ocssw/var/anc
LANGUAGE=zh_CN:zh
LANG=zh_CN.UTF-8
LESSCLOSE=/usr/bin/lesspipe %s %s
LESSOPEN=| /usr/bin/lesspipe %s
LIB3_BIN=/home/nkd/software/SeaDAS/ocssw/opt/bin
LIB3_CHECK=0
LIB3_DIR=/home/nkd/software/SeaDAS/ocssw/opt
LIB3_INC=/home/nkd/software/SeaDAS/ocssw/opt/include
LIB3_LIB=/home/nkd/software/SeaDAS/ocssw/opt/lib
LOGNAME=nkd
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
MANAGERPID=1105
NAVCTL=/home/nkd/software/SeaDAS/ocssw/share/seawifs/nav
NAVQC=/home/nkd/software/SeaDAS/ocssw/share/seawifs/nav
OCDATAROOT=/home/nkd/software/SeaDAS/ocssw/share
OCSSW_ARCH=linux_64
OCSSW_BIN=/home/nkd/software/SeaDAS/ocssw/bin
OCSSW_DEBUG=0
OCSSWROOT=/home/nkd/software/SeaDAS/ocssw
OCSSW_SVN=localhost
OCTS_REGISTRATION_TABLES=/home/nkd/software/SeaDAS/ocssw/share/octs/nav
OCVARROOT=/home/nkd/software/SeaDAS/ocssw/var
ORBCTL=/home/nkd/software/SeaDAS/ocssw/share/seawifs/nav
PATH=/home/nkd/software/SeaDAS/ocssw/opt/bin:/home/nkd/software/SeaDAS/ocssw/bin:/home/nkd/OCSSW_V2022/opt/bin:/home/nkd/OCSSW_V2022/bin:/home/nkd/.local/bin:/java/jdk1.8.0_421/bin:/java/jdk1.8.0_421/jre/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
PGSINC=/home/nkd/software/SeaDAS/ocssw/opt/EOS/include
PGSLIB=/home/nkd/software/SeaDAS/ocssw/opt/EOS/lib/linux64
PROJ_LIB=/home/nkd/software/SeaDAS/ocssw/opt/share/proj
PWD=/home/nkd/software/SeaDAS/bin
QT_ACCESSIBILITY=1
QT_IM_MODULE=ibus
SESSION_MANAGER=local/nkd-virtual-machine:@/tmp/.ICE-unix/1368,unix/nkd-virtual-machine:/tmp/.ICE-unix/1368
SHELL=/bin/bash
SHLVL=2
SSH_AGENT_PID=1320
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh
SWFTBL=/home/nkd/software/SeaDAS/ocssw/share/seawifs/qc
SWTBL=/home/nkd/software/SeaDAS/ocssw/share/seawifs
TERM=xterm-256color
USERNAME=nkd
USER=nkd
VTE_VERSION=6003
WINDOWPATH=2
XAUTHORITY=/run/user/1000/gdm/Xauthority
XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
XDG_CURRENT_DESKTOP=ubuntu:GNOME
XDG_DATA_DIRS=/usr/share/ubuntu:/usr/local/share/:/usr/share/:/var/lib/snapd/desktop
XDG_MENU_PREFIX=gnome-
XDG_RUNTIME_DIR=/run/user/1000
XDG_SESSION_CLASS=user
XDG_SESSION_DESKTOP=ubuntu
XDG_SESSION_TYPE=x11
XMODIFIERS=@im=ibus

The most common reason for differences in l2gen output is differences in the ancillary sources used. Make sure to use the getanc utility to identify and download the required ancillary inputs

Sean

Hi Sean, thanks a lot for your help! That's exactly the reason why I can't reproduce the same L2 product.