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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:

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 - - - - - - - - - - -


Product Lists for All Sensors

Level 2 Processing Flags and Masks

MODIS High-Resolution Processing Capabilities

MODIS High-Resolution Processing Instructions


Command Mode:

Usage: l2gen, 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.

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Updated: 10 July 2008 		NASA logo