l2gen
Description:
This program performs Level-2 processing on MODIS, SeaWiFS,
OCTS, or CZCS data and generates Level-2 geophysical
products by applying atmospheric corrections and bio-optical algorithms to the
sensor data. The input data levels required for l2gen processing are as follows:
- MODIS: input must be an Aqua or Terra L1B file
- SeaWiFS: input may be either an L1A or L1B file
- OCTS: input must be either a NASDA-format L1B file or
SIMBIOS-format L1B file
- CZCS: input must be a CZCS L1B file
For a thorough description of the full capabilities of l2gen and details on
the UNIX command-line user interface, please refer to the
L2GEN User's Guide.
There are hundreds of Level-2 products available for output. Any combination of these
products may be selected for output and written to up to 4 different
output files. Each sensor has it's own default definition of the output
products found in file $SDSDATA/sensor/sensor_def_l2prod.dat,
where "sensor" is modis, seawifs, octs, or czcs. The user can
modify these default definitions to define their own output product suite
for each supported sensor.
| Band number |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
| MODIS Wavelength (nm) |
412 |
443 |
488 |
531 |
551 |
667 |
678 |
748 |
869 |
- |
- |
- |
- |
- |
- |
- |
| HMODIS(Hi-resolution) Wavelength (nm) |
412 |
443 |
469 |
488 |
531 |
551 |
555 |
645 |
667 |
678 |
748 |
859 |
869 |
1240 |
1640 |
2130 |
| SeaWiFS Wavelength (nm) |
412 |
443 |
490 |
510 |
555 |
670 |
765 |
865 |
- |
- |
- |
- |
- |
- |
- |
- |
| OCTS Wavelength (nm) |
412 |
443 |
490 |
520 |
565 |
670 |
765 |
865 |
- |
- |
- |
- |
- |
- |
- |
- |
| CZCS Wavelength (nm) |
443 |
520 |
550 |
670 |
750 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
Command Mode:
Usage: l2gen, par="parfile", wait=wait OR
For Hi Res MODIS Aqua use: l2gen, 7, par="parfile", wait=wait OR
For Hi Res MODIS Terra use: l2gen, 8, par="parfile", wait=wait OR
Usage: l2gen,
par="parfile",
ifile="ifile",
geofile="geofile"(MODIS only),
ofile1="ofile1",
l2prod1=l2prod1,
ofile[2-4]="ofile[2-4]",
l2prod[2-4]=l2prod[2-4],
def_l2prod_file="def_l2prod_file",
slat=slat,
elat=elat,
slon=slon,
elon=elon,
spixl=spixl,
epixl=epixl,
sline=sline,
eline=eline,
dpixl=dpixl,
dline=dline,
ctl_pt_incr=ctl_pt_incr,
proc_ocean=proc_ocean,
proc_sst=proc_sst,
proc_land=proc_land,
atmocor=atmocor,
metsearch=metsearch,
ozonesearch=ozonesearch,
sstsearch=sstsearch,
disableftp=disableftp,
met1="met1",
met2="met2",
met3="met3",
ozone1="ozone1",
ozone2="ozone2",
ozone3="ozone3",
sst="sst",
water=water,
land=land,
ice=ice,
vcal_opt=vcal_opt,
gain=gain,
offset=offset,
filter_file=filter_file,
filter_opt=filter_opt,
brdf_opt=brdf_opt,
outband_opt=outband_opt,
glint_opt=glint_opt,
aer_opt=aer_opt,
aer_iter_max=aer_iter_max,
tau_a_per_band=tau_a_per_band,
tau_a=tau_a,
albedo=albedo,
glint_thres=glint_thresh,
absaer=absaer,
sunzen=sunzen,
satzen=satzen,
epsmin=epsmin,
epsmax=epsmax,
tauamx=tauamax,
nlwmin=nlwmin,
wsmax=wsmax,
sl_frac=sl_frac,
sl_pixl=sl_pixl,
rhoamin=rhoamin,
windspeed=windspeed,
windangle=windangle,
pressure=pressure,
ozone=ozone,
relhumid=relhumid,
watervapor=watervapor,
chloc2_wave=chloc2_wave,
chloc2_coef=chloc2_coef,
chloc3_wave=chloc3_wave,
chloc3_coef=chloc3_coef,
chloc4_wave=chloc4_wave,
chloc4_coef=chloc4_coef,
chlclark_wave=chlclark_wave,
chlclark_coef=chlclark_coef,
maskland=maskland,
maskbath=maskbath,
maskcloud=maskcloud,
maskglint=maskglint,
masksunzen=masksunzen,
masksatzen=masksatzen,
maskhilt=maskhilt,
maskstlight=maskstlight,
resolution=resolution,
gas_opt=gas_opt,
aer_wave_short=aer_wave_short,
aer_wave_long=aer_wave_long,
aer_swir_short=aer_swir_short,
aer_swir_long=aer_swir_long,
wait=wait,
help=hlp
Minimum command: l2gen, ifile="ifile",
geofile="geofile"(MODIS only), ofile1="ofile1"
OR l2gen, par="parfile"
Arguments/Keywords:
| par |
Input parameter file to be used for l2gen processing. The parameter file
may be generated in the interactive mode and then used in command mode.
Command line options specified by the user will override any of the same
parameters existing in the parameter file. |
|
ifile |
Directory
path and filename of the input SeaWiFS, MODIS, OCTS, or CZCS data
product. |
| geofile |
For MODIS processing only: Directory path and filename of the input
geolocation file used for navigation information. |
|
ofile1 |
Directory
path and filename of the output L2 file containing the products
specified
in the defaults file def_l2prod_file or by the l2prod1
keyword. |
|
def_l2prod_file |
Directory path and filename of the file containing the default level 2 output
products for a sensor platform.
(Default=$SDSDATA/sensor/sensor_def_l2prod.dat) |
|
l2prod1 |
The
list of product names to be included in the output file ofile1.
These product names are listed in the tables above for the 36 radiance
categories and the 44 miscellaneous products. |
|
ofile[2-4] |
Directory
path and filename of the output L2 files containing the products
specified
in the default file def_l2prod_file or by the l2prod[2-4] keyword. |
|
l2prod[2-4] |
The
product names (see tables above) to be output to ofile[2-4]. |
| slat |
Starting southern-most latitude to be processed. (Default=0).
|
| elat |
Ending northern-most latitude to be processed. (Default=0).
|
| slon |
Starting western-most longitude to be processed. (Default=0).
|
| elon |
Ending eastern-most longitude to be processed. (Default=0).
|
|
spixl |
Starting pixel number to be processed. (Default=1) |
| epixl |
Ending pixel number to be processed. (Default=0, meaning the end of the
scanline) |
| sline |
Starting scan line number to be processed. (Default=1) |
|
eline |
Ending scan line number to be processed.
(Default=0, meaning the last line of the file) |
| dpixl |
Pixel subsampling rate. (Default=1) |
|
dline |
Line subsampling rate. (Default=1) |
|
ctl_pt_incr |
Control-point pixel increment for lat/lon arrays. Setting this to 1 will
result in lat/lon arrays with the same dimensions of the data image and
a larger level 2 file. (0 = optimize, default = 8) |
Optional Ancillary data files:
| metsearch |
If this flag is set, the automatic MET
file
search function will be activated
and prior to running l2gen, SeaDAS will attempt to locate the appropriate MET
files first on the user's hard disk, and then on the OBPG's ftp server (unless
the disableftp flag has been set).
|
| ozonesearch |
If this flag is set, the automatic OZONE
file
search function will be activated
and prior to running l2gen, SeaDAS will attempt to locate the appropriate OZONE
files first on the user's hard disk, and then on the OBPG's ftp server (unless
the disableftp flag has been set).
|
| sstsearch |
If this flag is set, the automatic SST
file
search function will be activated
and prior to running l2gen, SeaDAS will attempt to locate the appropriate OISST
file first on the user's hard disk, and then on the OBPG's ftp server (unless
the disableftp flag has been set).
|
| disableftp |
If this flag is set, ftp searches/downloads will be disabled for the automatic
ancillary
file
search functions. If ancillary files exist on the local hard disk,
they will still be found by metsearch, ozonesearch, and sstsearch.
|
| met1 |
Directory path and filename of the climatological product or the near-real-time
(NRT) meteorological ancillary data product available for the nearest time
preceding the time of ifile product's first scan
line. (Default='$SDSDATA/common/S19461993_COADS_GEOS1.MET_noon') |
| met2 |
Directory path and filename of the NRT meteorological ancillary
data product available for the nearest time following
the time of ifile product's first scan line. |
| met3 |
Directory path and filename of the NRT meteorological ancillary data
product for the nearest time following the time of
ifile product's last scan line. |
| ozone1 |
Directory path and filename of the climatological product or the near-real-time
(NRT) ozone ancillary data product available for the nearest time
preceding the time of ifile product's first scan
line. (For TOVS data, the center point time is used to represent the
time of that product.) (Default='$SDSDATA/common/S19891991_TOMS.OZONE') |
| ozone2 |
Directory path and filename of the NRT ozone ancillary data product
available for the nearest time following the time of
ifile product's first scan line. (For TOVS data,
the center point time is used to represent the time of that product.) |
| ozone3 |
Directory path and filename of the NRT ozone ancillary data
product for the nearest time following the time of
ifile product's last scan line. (For TOVS data,
the center point time is used to represent the time of that product.) |
| sst |
Directory path and filename of the ancillary SST input data. This is
currently used to set the tricodesmium flag. For MODIS processing,
OISST files can be specified here for the SST guess in the non-linear
SST algorithm (NLSST).
(Default='$SDSDATA/common/sst_climatology.hdf') |
| land |
Directory path and filename of the land-mask input file.
(Default='$SDSDATA/common/landmask.dat') |
| water |
Directory path and filename of the shallow water mask input file used for setting
the l2_flags bit to indicate shallow water (defined as 30m) areas
(McClain et al. 1995). (Default='$SDSDATA/common/watermask.dat') |
| ice |
Directory path and filename of the ice-mask input file.
(Default='$SDSDATA/common/icemask.hdf') |
Calibration control options:
|
vcal_opt |
Vicarious
calibration option controls whether gain and offset sensor defaults or
input parameters are used:
0
- sensor defaults
1
- default offset, parameter gain
2
- default gain, parameter offset
3
- parameter gain and offset
|
|
gain |
Calibration
gain factors to multiply TOA radiance in each band; the default gain
values
are read from the $SDSDATA/sensor/sensor_table.dat
file. |
|
offset |
Calibration
offset adjustment to TOA radiance; the default gain values are read
from
the $SDSDATA/sensor/sensor_table.dat file. |
Algorithm control options:
| proc_ocean |
Apply ocean processing. 1= On, 0 = Off. (Default is On) |
| proc_sst |
Apply SST processing. 1= On, 0 = Off. (Default is On).
(MODIS Only) |
| proc_land |
Apply land processing. 1= On, 0 = Off. (Default is Off) |
| atmocor |
Apply atmospheric correction. 1= On, 0 = Off. (Default is On) |
|
filter_file |
Directory path and filename of the filter file that contains the filter method
and information to be applied to the L1B data when filter_opt is set
to 1. (Default=$SDSDATA/sensor/sensor_filter.dat) |
|
filter_opt |
Option
for filtering the L1B data with the method specified in filter_file.
1=apply filtering , 0=do not apply filtering.
(Default for OCTS=1, Default for others=0) |
|
brdf_opt |
Option
for running bi-directional reflectance correction factor.
|
0=No correction |
|
1=Fresnel
geometry correction for flat ocean surface |
|
3=Morel
(gothic-R) geometry correction for wind roughened ocean |
|
7=Morel
f/Q & gothic-R (default) |
|
|
gas_opt |
Gaseous
transmittance bitmap selector. This option corrects for gaseous absorption.
It is a bitmapped value, so you should add together the values for each
option you want. For example, if you wanted all of the values Ozone, CO2,
NO2, and H2O, then you would add 1+2+4+8=15.
|
Ozone(1)(Default) |
|
CO2(2) |
|
NO2(4) |
|
H2O(8) |
|
|
resolution |
Reduced/Expanded
resolution value(MODIS only).
|
Reduced band 1km(-1) |
|
Expanded band 1km(1000) |
|
Expanded band 500m(500) |
|
Expanded band 250m(250) |
|
|
outband_opt |
SeaWiFS/OCTS
out-of-band corrections
(Default=2 , full correction for SeaWiFS and OCTS) |
|
glint_opt |
Correct
for residual glint radiance. 0 = off, 1 = on.
(Default=1) |
|
aer_opt |
Option for aerosol calculation mode. (Default=-3)
|
1 |
Multi-scattering
with fixed model (Oceanic, 99% humidity) |
|
2 |
Multi-scattering
with fixed model (Maritime, 50% humidity) |
|
3 |
Multi-scattering
with fixed model (Maritime, 70% humidity) |
|
4 |
Multi-scattering
with fixed model (Maritime, 90% humidity) |
|
5 |
Multi-scattering
with fixed model (Maritime, 99% humidity) |
|
6 |
Multi-scattering
with fixed model (Coastal, 50% humidity) |
|
7 |
Multi-scattering
with fixed model (Coastal, 70% humidity) |
|
8 |
Multi-scattering
with fixed model (Coastal, 90% humidity) |
|
9 |
Multi-scattering
with fixed model (Coastal, 99% humidity) |
|
10 |
Multi-scattering
with fixed model (Tropospheric, 50% humidity) |
|
11 |
Multi-scattering
with fixed model (Tropospheric, 90% humidity) |
|
12 |
Multi-scattering
with fixed model (Tropospheric, 99% humidity) |
|
0 |
Single-scattering
white aerosols |
|
-1 |
Multi-scattering
with 2-band model selection |
|
-3 |
Multi-scattering
with 2-band model selection and NIR correction |
|
-9 |
Multi-scattering
with 2-band model selection and SWIR correction(Hi-res MODIS only) |
|
|
aer_wave_short |
Lower wavelength used for aerosol model selection.(Hi-res MODIS only)
(Default=748) |
|
aer_wave_long |
Upper wavelength used for aerosol model selection and aerosol
concentration.(Hi-res MODIS only)
(Default=869) |
|
aer_swir_short |
Lower SWIR wavelength used for aerosol model selection.(Hi-res MODIS only)
(Default=1240) |
|
aer_swir_long |
Upper SWIR wavelength used for aerosol model selection and aerosol
concentration.(Hi-res MODIS only)
(Default=2130) |
|
tau_a_per_band |
If
specified, aerosol path reflectance will be derived from spectral
distribution
of tau_a_per_band for all pixels. |
|
tau_a |
Aerosol
optical thickness at 865nm. If specified, and aer_opt is set
1-12,
aerosol reflectance will be derived from tau_a and fixed model for all
pixels. (Default=-1.0) |
|
aer_iter_max |
Maximum number of aerosol iterations for NIR correction.
(Default=10) |
|
albedo |
Cloud threshold for band 8 surface reflectance setting the l2_flags bit #10.
(Default=0.027) |
|
glint_thresh |
Sun
glint threshold (fraction of F0(865)) used in calculations for setting
the l2_flags bit #4. (McClain et al., 1995). (Default=0.005) |
|
absaer |
Absorbing
aerosol threshold on aerosol index. Set to -1 to avoid the computation
entirely. (Default=0.5) |
|
sunzen |
Solar
zenith angle threshold (degrees) used for setting the l2_flags bit #13.
(McClain et al., 1995). (Default=75.0) |
|
satzen |
Spacecraft
zenith angle threshold (degrees) for setting the l2_flags bit #6.
(McClain
et al., 1995). (Default=60.0) |
|
epsmin |
Minimum
epsilon value used for setting the l2_flags bit #23. (Default=0.85) |
|
epsmax |
Maximum
epsilon value used for setting the l2_flags bit #23. (Default=1.35) |
|
tauamax |
Maximum
865 aerosol optical depth used for setting the l2_flags bit #14. (Default=0.3) |
|
nlwmin |
Minimum
nlw(555) used for setting the l2_flags bit #15. (Default=0.15) |
|
wsmax |
Windspeed limit on white-cap correction. (Default=8.0 m/s) |
|
sl_frac |
Lt
865 threshold for stray-light correction. (SeaWiFS only.) (Default=0.25) |
|
sl_pixl |
Number
of LAC pixels over which stray-light correction is applied. 0 = no
correction,
-1 = program defaults
(4
for GAC, 3 for LAC) |
|
rhoamin |
Minimum
NIR aerosol reflectance at which aerosol model selection will be
attempted. (Default=0.0001) |
|
windspeed |
Wind
speed ancillary override value. If greater than -999, the scalar
values will be used to replace the interpolated ancillary inputs for
every pixel in the scene. (Default=-1000). (m/s) |
|
windangle |
Wind
direction ancillary override value. If greater than -999,
the
scalar values will be used to replace the interpolated ancillary inputs
for every pixel in the scene. (Default=-1000). (deg, N=0 E=90) |
|
pressure |
Surface
pressure ancillary override value. If greater than -999,
the
scalar values will be used to replace the interpolated ancillary inputs
for every pixel in the scene. (Default=-1000). (mb) |
|
ozone |
Ozone
concentration ancillary override value. If greater than
-999,
the scalar values will be used to replace the interpolated ancillary
inputs
for every pixel in the scene. (Default=-1000). (cm) |
|
relhumid |
Relative
humidity ancillary override value. If greater than -999, the
scalar
values will be used to replace the interpolated ancillary inputs for
every
pixel in the scene. (Default=-1000). (%) |
|
watervapor |
Water
vapor concentration ancillary override value. If greater
than
-999, the scalar values will be used to replace the interpolated
ancillary
inputs for every pixel in the scene. (Default=-1000). (g/cm^2) |
Masking keywords:
|
maskland |
Mask
out all land pixels: 0=off, 1=on. (Default=1) |
|
maskbath |
Mask
out shallow water: 0=off , 1=on. (Default=0) |
|
maskcloud |
Mask out pixels for which cloud albedo is above user defined threshold:
0=off, 1=on. (Default=1) |
|
maskglint |
Mask out pixels with sun glint: 0=off, 1=on. (Default=0) |
|
masksunzen |
Mask out pixels with large solar zenith angle: 0=off, 1=on. (Default=0) |
|
masksatzen |
Mask out pixels with large sensor zenith angle: 0=off, 1=on. (Default=0) |
|
maskhilt |
Mask out pixels where total radiance greater than knee value: 0=off, 1=on.
(Default=1) |
|
maskstlight |
Mask
out pixels with stray light: 0=off, 1=on. (Default=1) |
General program control keywords:
|
wait |
|
0
or not set |
Spawn the underlying process program as a background job and return
immediately to the SeaDAS prompt. (Default) |
|
Set
and non-zero |
Spawn
the underlying process program as a foreground job and wait for it to
complete
before returning control to the SeaDAS prompt. |
|
|
help |
To
list all arguments and keywords for this program. |
Interactive Mode:
The l2gen GUI can be accessed under the SeaDAS main window's "Process"
menu. For example to access the l2gen GUI for MODIS processing choose
Process -> MODIS -> l2gen,4. The l2gen GUI can also be started
from the SeaDAS command line by typing l2gen,4 where "4" is the
"sat_id" for MODIS. Also, typing "l2gen" from the command line will bring up
an intermediary window that will prompt for sensor selection.
The l2gen GUI consists of one window with separate tabs for
File Selection, Subset/Subsample, Processing
Options, and Flag Thresholds as outlined below:
File Selection Tab:
Input and Output data files:
| SeaWiFS, MODIS, OCTS, CZCS Input file |
Directory path and filename of the SeaWiFS (L1A or L1B),
or MODIS, OCTS, CZCS L1B input file. |
| Select (Input file) |
Interactively select the input file. The selected file will be displayed
in the input file field.
NOTE: This interactive input file selection also triggers the automatic
MET, OZONE, and SST file search functions. |
| L2 output file 1 to 4 |
Directory path and filename of the up to 4 possible output files to
contain the specified Level-2 products. |
| Select L2 Products |
Interactively specify the products for output files 1 to 4. If not
interactively selected, the default definition files will be used.
See the Level-2 Products Selection Window
and keywords def_l2prod_file,
l2prod1, l2prod[2-4]
in command mode. |
Optional Ancillary data files:
Search Menus for
MET, OZONE, SST |
These three menus set the behavior of the automatic ancillary file
search functions. All three search functions are triggered after an
input L1A or L1B file is selected using the input file Select button.
Menu options are:
- Search DISK,FTP: The local hard disk is first searched for
the optimal ancillary files. If not found, the OBPG ftp server is then queried and if valid
files are found, they are automatically downloaded.
- Search DISK ONLY: This option turns off the automatic download functionality.
- Searching OFF: When this option is selected, unless ancillary files have been manually
entered in the text boxes, the climatology will be used.
|
| MET file 1 |
Directory path and filename of the climatological product or the near-real-time
(NRT) meteorological ancillary data product available for the nearest time
preceding the time of ifile product's first scan
line. (Default='$SDSDATA/common/S19461993_COADS_GEOS1.MET_noon') |
| MET file 2 |
Directory path and filename of the NRT meteorological ancillary
data product available for the nearest time following
the time of ifile product's first scan line. |
| MET file 3 |
Directory path and filename of the NRT meteorological ancillary data
product for the nearest time following the time of
ifile product's last scan line. |
| OZONE file 1 |
Directory path and filename of the climatological product or the near-real-time
(NRT) ozone ancillary data product available for the nearest time
preceding the time of ifile product's first scan
line. (For TOVS data, the center point time is used to represent the
time of that product.) (Default='$SDSDATA/common/S19891991_TOMS.OZONE') |
| OZONE file 2 |
Directory path and filename of the NRT ozone ancillary data product
available for the nearest time following the time of
ifile product's first scan line. (For TOVS data,
the center point time is used to represent the time of that product.) |
| OZONE file 3 |
Directory path and filename of the NRT ozone ancillary data
product for the nearest time following the time of
ifile product's last scan line. (For TOVS data,
the center point time is used to represent the time of that product.) |
| SST file |
Directory path and filename of the ancillary SST input data.
This is currently used to set the tricodesmium flag. For MODIS
processing, OISST files can be specified here for the SST guess in
the non-linear SST algorithm (NLSST).
(Default='$SDSDATA/common/sst_climatology.hdf') |
General program control options:
| Parameter file |
The parameter file name that the input parameters are to be saved to or
loaded from depending on the selection of the Option drop down menu button. |
| Options |
Drop down menu button for options on the parameter file.
| Load |
To load and display the parameter values on the screen from the parameter file. |
| Save |
To save the parameter values displayed on the screen to the parameter file. |
| Select |
To display the File Selection Window for selecting the parameter file. |
|
| Run |
To start the l2gen program. |
| Run(BG) |
To start and run the l2gen program as a background process. |
| Help |
Display the HTML help for this program in the user's HTML viewer. |
| Quit |
To quit this program. |
Subset/Subsample Tab:
Subset/Subsample options:
| Latitude range |
Starting to ending latitudes to be processed. |
| Longitude range |
Starting to ending longitudes to be processed. |
| Pixel range |
Starting to ending pixel numbers to be processed. |
| Line range |
Starting to ending line numbers to be processed. |
| Pixel subsampling interval |
Pixel subsampling rate. |
| Line subsampling interval |
Line subsampling rate. |
| Control-point pixel increment |
Control-point pixel increment for lon/lat arrays. Setting this to "1" will
result in lat/lon arrays with the same dimensions of the data image and
a larger level 2 file. |
Processing Options Tab:
Processing options:
|
Ocean
processing mode option |
Apply
ocean processing. (Default is On) |
|
Atmospheric
Correction mode option |
Apply
atmospheric correction. (Default is On) |
|
Land
processing mode option |
Apply
land processing. (Default is Off) |
|
SST
processing mode option |
Apply
SST processing. (Default is Off). (MODIS only) |
|
Aerosol
mode option |
Option
for aerosol calculation mode. (Default=-3)
|
1 |
Multi-scattering
with fixed model (Oceanic, 99% humidity) |
|
2 |
Multi-scattering
with fixed model (Maritime, 50% humidity) |
|
3 |
Multi-scattering
with fixed model (Maritime, 70% humidity) |
|
4 |
Multi-scattering
with fixed model (Maritime, 90% humidity) |
|
5 |
Multi-scattering
with fixed model (Maritime, 99% humidity) |
|
6 |
Multi-scattering
with fixed model (Coastal, 50% humidity) |
|
7 |
Multi-scattering
with fixed model (Coastal, 70% humidity) |
|
8 |
Multi-scattering
with fixed model (Coastal, 90% humidity) |
|
9 |
Multi-scattering
with fixed model (Coastal, 99% humidity) |
|
10 |
Multi-scattering
with fixed model (Tropospheric, 50% humidity) |
|
11 |
Multi-scattering
with fixed model (Tropospheric, 90% humidity) |
|
12 |
Multi-scattering
with fixed model (Tropospheric, 99% humidity) |
|
0 |
Single-scattering
white aerosols |
|
-1 |
Multi-scattering
with 2-band model selection |
|
-3 |
Multi-scattering
with 2-band model selection and NIR correction |
|
-9 |
Multi-scattering
with 2-band model selection and SWIR correction(Hi-res MODIS only) |
|
|
Resolution |
Reduced/Expanded
resolution value(MODIS only).
|
Reduced band 1km(-1) |
|
Expanded band 1km(1000) |
|
Expanded band 500m(500) |
|
Expanded band 250m(250) |
|
|
Gaseous Transmittance Selector |
Gaseous
transmittance bitmap selector. This option corrects for gaseous absorption.
It is a bitmapped value, so you should add together the values for each
option you want. For example, if you wanted all of the values Ozone, CO2,
NO2, and H2O, then you would add 1+2+4+8=15.
|
Ozone(1)(Default) |
|
CO2(2) |
|
NO2(4) |
|
H2O(8) |
|
|
Aerosol Wavelength Lower |
Lower wavelength used for aerosol model selection.(Hi-res MODIS only)
(Default=748) |
|
Aerosol Wavelength Upper |
Upper wavelength used for aerosol model selection and aerosol
concentration.(Hi-res MODIS only)
(Default=869) |
|
SWIR Wavelength Lower |
Lower SWIR wavelength used for aerosol model selection.(Hi-res MODIS only)
(Default=1240) |
|
SWIR Wavelength Upper |
Upper SWIR wavelength used for aerosol model selection and aerosol
concentration.(Hi-res MODIS only)
(Default=2130) |
| Maximum iterations |
Maximum number of aerosol iterations for NIR correction.
(Default=10). See keyword aer_iter_max
in command mode. |
| Aerosol optical depth |
Aerosol optical thickness at 865nm. If specified, and aer_opt is set
1-12,
aerosol reflectance will be derived from tau_a and fixed model for all
pixels. (Default=-1.0).
See keyword tau_a in command mode. |
| Apply filtering to the input |
Option for filtering the L1B data with the method specified in filter_file.
(Default for OCTS=apply, Default for others=do not apply). See keyword
filter_opt in command mode. |
| Apply brdf option |
Option for running bi-directional reflectance correction factor. See keyword
brdf_opt in command mode. |
| Correct for residual glint radiance |
Correct for residual glint radiance.
(Default=On). See keyword glint_opt in
command mode. |
|
L2
mask flags selection |
Mask
out pixels with specific attributes. See masking
keywords in command mode. |
| Calibration gain multiplier |
Use sensor defaults, or use gain parameter.
See keyword gain in command mode. |
| Calibration offset |
Use sensor defaults, or use offset parameter.
See keyword offset in command mode. |
| Landmask file |
Directory path and filename of the land-mask input file.
(Default='$SDSDATA/common/landmask.dat') |
| Watermask file |
Directory path and filename of the shallow water mask input file used for setting
the l2_flags bit to indicate shallow water (defined as 30m) areas (McClain
et al. 1995). (Default='$SDSDATA/common/watermask.dat') |
| Icemask file |
Directory path and filename of the ice-mask input file.
(Default='$SDSDATA/common/icemask.hdf') |
| Filtering file |
Directory path and filename of the filter file that contains the filter method
and information to be applied to the L1B data when applying
filtering to the input is set.
(Default=$SDSDATA/sensor/sensor_filter.dat) |
| Polarization Sensitivity file |
Directory path and filename suffix of the polarization sensitivity files. These files
apply only to MODIS processing.
(Default=$SDSDATA/sensor/cal/polcor_sensor) |
Flag Thresholds Tab:
Flag thresholds:
|
Cloud
albedo threshold |
Cloud
threshold for band 8 surface reflectance setting the l2_flags bit #10.
(Default=0.027).
See keyword albedo in command mode. |
|
Sun
glint threshold |
Sun
glint threshold (fraction of F0(865)) used in calculations for setting
the l2_flags bit #4. (McClain et al., 1995).
(Default=0.005).
See keyword glint_thresh in the
command
mode. |
|
Absorbing
aerosol threshold |
Absorbing
aerosol threshold on aerosol index. Set to -1 to avoid the computation
entirely.
(Default=0.5). See keyword absaer in the
command
mode. |
| Sun zenith angle threshold |
Solar zenith angle threshold (degrees) used for setting the l2_flags bit #13.
(McClain et al., 1995). (Default=75.0).
See keyword sunzen in command mode. |
| Satellite zenith angle threshold |
Spacecraft zenith angle threshold (degrees) for setting the l2_flags bit #6.
(McClain et al., 1995). (Default=60.0).
See keyword satzen in command mode. |
| Minimum epsilon |
Minimum epsilon value used for setting the l2_flags bit #23.
(Default=0.85).
See keyword epsmin in command mode. |
| Maximum epsilon |
Maximum epsilon value used for setting the l2_flags bit #23.
(Default=1.35).
See keyword epsmax in command mode. |
| Minimum nLw (555) |
Minimum nlw(555) used for setting the l2_flags bit #15.
(Default=0.15).
See keyword nlwmin in command mode. |
| Windspeed limit |
Windspeed limit on white-cap correction.
(Default=8.0 m/s). See keyword wsmax in the
command mode. |
| Maximum 865 aerosol optical depth |
Maximum 865 aerosol optical depth used for setting the l2_flags bit #14.
(Default=0.3).
See keyword tauamax in command mode. |
| Minimum NIR aerosol reflectance |
Minimum NIR aerosol reflectance at which aerosol model selection will be
attempted.
(Default=0.0001).
See keyword rhoamin in command mode. |
| Stray-light Lt 865 threshold |
Lt 865 threshold for stray-light correction. (SeaWiFS only.)
(Default=0.25). See keyword sl_frac in the
command mode. |
| Number of pixels for stray light correction |
Number of LAC pixels over which stray-light correction is applied. 0 = no
correction, -1 = program defaults.
(Default: 4 for GAC, 3 for LAC).
See keyword sl_pixl in command mode. |
| Windspeed ancillary override |
Wind speed ancillary override value. If greater than -999, the scalar
values will be used to replace the interpolated ancillary inputs for
every pixel in the scene. (Default=-1000). (m/s) |
| Wind direction ancillary override |
Wind direction ancillary override value. If greater than -999,
the scalar values will be used to replace the interpolated ancillary inputs
for every pixel in the scene. (Default=-1000). (deg, N=0 E=90) |
| Pressure ancillary override |
Surface pressure ancillary override value. If greater than -999,
the scalar values will be used to replace the interpolated ancillary inputs
for every pixel in the scene. (Default=-1000). (mb) |
| Ozone concentration ancillary override |
Ozone concentration ancillary override value. If greater than
-999, the scalar values will be used to replace the interpolated ancillary
inputs for every pixel in the scene. (Default=-1000). (cm) |
| Relative humidity ancillary override |
Relative humidity ancillary override value. If greater than -999, the
scalar values will be used to replace the interpolated ancillary inputs for
every pixel in the scene. (Default=-1000). (%) |
| Water vapor concentration ancillary override |
Water vapor concentration ancillary override value. If greater
than -999, the scalar values will be used to replace the interpolated
ancillary inputs for every pixel in the scene.
(Default=-1000). (g/cm^2) |
Level-2 Products Selection Window:
Description: This window allows the user to select Level-2
output products for the output file specified in the l2gen main window.
Global and default product selection:
| Select all (global) |
Select every possible product listed below. |
| Select none (global) |
Deselect every possible product listed below. |
| Select defaults |
Select default products either from SeaDAS defaults, or
your own personal defaults from the Save Defaults button. |
| Save defaults |
Save your own personal default products for this satellite. |
Manual product selection: This section allows the user to
interactively select any combination of the available output products. Each
product can be individually selected by pressing the button in front of it.
Groups of buttons can be selected or deselected by using the Select all or
Select none buttons in each category.
| Select all (for all categories) |
Select all bands in this section. |
| Select none (for all categories) |
Deselect all bands in this section. |
| Okay |
To return the selected product list file in the Selection field (if selected),
or the list of products that have been manually selected, and quit the
Product Selection Window. |
| Quit |
Destroy this window and return to the main l2gen window. |
