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Topic gpt MosaicGeneral By knowles Date 2021-02-18 11:43
Hi Amita,

As previously noted in this thread, rhos_412 and other surface reflectances can in fact be negative, and for that matter could be greater than 1.0 as well.  Cloud shadow and cloud tops are 2 possible instances in which this might occur.  There could be other instances.  The fill value (-32767.0) is another instance.

The likelihood that the float value rhos_412 precisely equals zero is extremely small.  Most likely you want something like (rhos_412 > 0.0 && rhos_412 <= 1.0) instead of (rhos_412 != 0) in your expression.  If you wish to retain the "official" range then you want (rhos_412 >= -0.05 && rhos_412 <= 1.0).
Updating to SeaDAS 7.5.3 will fix your GUI problem regarding autofill of the extractor GUI.

Alternatively, you can run this at the command line to retrieve the pixel values (using the example previously mentioned in this post).  Note in this case you will need to first generate GEO and L1B non-extracted files and then use them as input files to this command to determine the pixel coordinates.  Then you can do the steps previously mentioned in this post:

lonlat2pixline  A2010283180500.L1B_LAC A2010283180500.GEO -78.0 37.0 -75.0 39.0
# 701 985 1023 1289


After entering the final lat/lon textfield, try clicking on another textfield to trigger the autofill ... do the pixel textfields autofill if you do this?  The pixels values get autofilled via the "Run" button action, however you won't see it because the GUI closes and runs, so we need to know whether autofill is working for you.

Also what version of SeaDAS are you using and have you updated the OCSSW processors lately?  You might try updating OCSSW just in case, it's quick for updates and will rule out any issues there.

Topic Get the value from scatter plot By knowles Date 2021-01-07 11:30
A scatterplot cannot create or export ROI data.  You might need to clarify what you are doing and how you are exporting the data.  I do not see a region of interest vector in the image which you show.  You didn't check the ROI checkbox so your scatterplot is based on the whole image.  I do see that you managed to draw a partial ellipse onto the scatterplot.  I do not know how you did this, but I'm not aware of any functionality within this SeaDAS tool which supports this. 

To create a quasi true color plate carrée mapped image for a ROI (region of interest) within a MODIS file the following GUI steps can be done:

Example file:
Region of interest: north=39.0, south=37.0, west=-78.0, east=-75.0

1. Create level-1A extract file:
   Menu > OCSSW > extractor ..
           infile = A2010283180500.L1A_LAC, and fill in geo coordinate fields with ROI, (pixel fields will auto-fill)
           ofile = A2010283180500.L1A_LAC.sub

2. Create GEO file for extract:
    Menu > OCSSW > modis_GEO
           file = A2010283180500.L1A_LAC
           output = A2010283180500.GEO.sub

3. Create level-1B for extract:
   Menu > OCSSW > modis_L1B
           ifile = A2010283180500.L1A_LAC
           geofile = A2010283180500.GEO.sub
           Note: ofile is auto-named (in this case A2010283180500.L1B_LAC.sub)

4. Create mapped image for extract:
    Menu > OCSSW > l1mapgen
           ifile = A2010283180500.L1B_LAC.sub
           ofile = A2010283180500.sub.png
           resolution = (choose 1000, 500, 250, -1)   *-1 is a default 
           oformat = (choose ppm, png, etc.)
           width = 1000 (this field may need adjustment depending of desired resolution and image size)
           Note: leave geofields = -999 (disabled).  These fields may be used directly on the non-extracted level-1B file however in this case
                    (at least currently) the resultant image is cropped but not mapped

Attached is the output image at 250m resolution.
Attachment: A2010283180500.L1B_MAP.png (472k)
Topic Draw polygon on a scatter plot in SeaDAS By knowles Date 2021-01-07 09:18
The scatterplot is created from the image.  You can mask areas of the image by drawing on the image using the polygon, ellipse, ... tools.  You can then apply this mask to refine the scatterplot.  However there are no tools in SeaDAS to enable the user to draw on the scatterplot and have that result transfer to the image.

Topic maskcloud By knowles Date 2020-10-28 11:22

Pixels can have NaN values for products for a multitude of reasons and NaN pixels can have a multitude of flags.  You can view all the flags for a pixel by hovering over it and observing all its flag values within the Pixel info tool window (... or by placing a pin on it and using this tool).  I believe the vertical flagged area to the right of your image is likely associated with high sensor zenith angle (HISATZEN flag).

Negative rhos values will likely be flagged LOWLW.  Cloud shadow can be one cause for negative rhos values, but I will leave clarification regarding the reasons for negative rhos values to others who may wish to add in on this.

Topic Resampling By knowles Date 2020-10-26 10:17
You can use the Collocate tool with HICO as the reference/master and VIIRS as the dependent file.  This will generate a new file containing all the raster data bands from both input files.  The pixels of the generated file will geographically match those of the L2 HICO pixel.  Since all data will then be in a single file, comparison tools can then be used.

Alternatively you can use the Reproject Tool or l3mapgen to individually map each file to a consistent matching map resolution. 

Note: sensors (such as MODIS) which have bowtie pixel mapping concerns can be problematic if being directly used as the reference file in the Collocate tool.

Topic Reprojecting L1 image By knowles Date 2020-10-21 10:22
No, you cannot reproject L1 images and then run l2gen.  All the science processors within the OCSSW menu are strict science data processors with specific input file types and formats, tracking through specific science data levels.  The other more generic GUI/GPT tools such as Reproject, Subset, Collocate, etc. are not part of OCSSW.  So you cannot use the output of the non-OCSSW tools as input to the OCSSW software.

Note that there are "reproject" tools within OCSSW.  This would involve taking the level-2 file and running it through l2bin and then through l3mapgen.

Topic Flags and Reprojected files By knowles Date 2020-10-19 09:34
You can apply the flag masks using the original unprojected flag by setting the following field within the Reproject operator:

The flags themselves should not be reprojected as they really have no meaning since they are tied to multiple unprojected pixels.
I've never used Arcgis, but the shapefile export tool should work fine in SeaDAS for contours.  You can test this by creating contours in SeaDAS, exporting the contours from within the File Info window (right click on Vector and select "Export Geometry as Shapefile").  Then open another scene file within SeaDAS in a comparable location and load in the shapefile.  I just tested this and it works correctly for my test case.

Topic Cloud Masking By knowles Date 2020-09-17 09:53
Hi Amita,

I'm answering in regards to how you would do cloud masking on a rhos_865 band with other SeaDAS GUI tools instead of cloud masking with l2gen.

In the Mask Manager tool window click on "f(x)" icon.  Click "Show bands".  At this point you can click and create a math expression based on the rhos_865 band.  Alternatively you can type it directly into the window.

Here is a sample expression you could use based on our default cloud threshold:
"rhos_865 > 0.027"

After clicking OK the cloud mask is created and displayed in the SeaDAS GUI.

Topic OLI L2 data By knowles Date 2020-08-27 10:05
If you are a loading a level-2 file into SeaDAS the Mask Manager panel shouldn't be blank.  Make sure your file is being loaded correctly and being recognized as a level-2 file.  To determine which "Product reader" SeaDAS is actually using on your file, go to File Manager, click on the filename, select Menu > Analysis > Band Info.  It should contain a field something like "Product Reader = SeaDAS-Supported Level 2 Products".

If this isn't working you can always use the Mask Manager to create masks based on the flags.  In Mask Manager click on "f(x)" then create a mask based on a single or composite of the selectable level2 flags within the GUI.

Topic L2gen processing speed By knowles Date 2020-08-21 10:21
The MODIS instruments only contain 2 bands at 250m (645nm and 859nm).  These are not blue/green or IR bands so it rules out the SST and chlor_a algorithms.  You do have options regarding fine tuning atmospheric correction.  You can use l2gen to process the 645 and 859 band products to 250m (rhot_645, rhot_859, rhos_645, rhos_859, Rrs_645, and Rrs_859, etc.).  If you process chlor_a to 250m using l2gen you will get an interpolated result for this product.

Topic Change cloud maks for 250m products By knowles Date 2020-07-27 14:16
Yes you can improve the resolution of the level2 flag mask "CLDICE", depending of course on which sensor mission you are using.  I'm guessing that you are referring to MODIS which contains 250m, 500m, 1000m bands and can be processed by SeaDAS at any of these resolutions.  The cloud flag/mask "CLDICE" is generated based on the surface reflectance band (rhos) of the sensor's longest NIR band (in the case of MODIS rhos_869).  This default band is 1km resolution.  To achieve a CLDICE mask at 250m, you can use the 250m 859nm band instead (rhos_859).  Here is an example of SeaDAS OCSSW command line operations to do this using the file A2010283180500.L1A_LAC:

$ A2010283180500.L1A_LAC

$ A2010283180500.L1A_LAC A2010283180500.GEO

$ A2010283180500.L1B_LAC

$ l2gen ifile=A2010283180500.L1B_LAC ofile=A2010283180500.L2_QKM_OC2 geofile=A2010283180500.GEO l2prod="rhos_859 rhos_869" resolution=250 cloud_wave=859 cloud_thresh=0.027 par=A2010283180500.L1B_LAC.anc

cloud_wave=859 is where you are specifying to use the 250m rhos_859 band.  l2prod is a list of your choice of products, keeping in mind that the standard OC products such as chlor_a are 1km.  You can also tweak the param "cloud_thresh" default threshold if you really wish to be more or less aggressive in the cloud flagging.  "cloud_thresh" is the threshold of the rhos band "cloud_wave" at which the CLDICE flag gets triggered.

The attached images show output results of this scene over Lake Ontario, showing band rhos_859, with mask on and with mask off.
Attachment: mask.png (258k)
Attachment: nomask.png (359k)
Very likely, yes you can find data there in June at higher resolutions.  I just used the L2 browser and did a quick visual scan of the true color (TC) images and found many files for June 2020 matching your region (most of them cloudy but not all).  The level2 MODIS files available are at 1km (nadir) resolution.  For the 645nm band to achieve 500m or 250m you would need to get the L1A files and process them.

This is my browser results for the full MODIS Aqua mission for June using your region which returns over 900 files (most of them cloudy but not all):

Here's two files in your region:
Attachment: A2020175020500.L1B_LAC_BRS.png - A2020175020500.L1B_LAC_BRS (38k)
Attachment: A2020166021000.L1B_LAC_BRS.png - A2020166021000.L1B_LAC_BRS (39k)
Barry, this case study video tutorial illustrates the use of the Collocation Tool in comparing files and using statistics.

More videos can be found here:

Oftentimes with SeaDAS there are 2 or more ways of doing something.  Another approach would be to use the Collocation Tool.  This tool will create a new file which contains all the bands of your 2 source files.  If the source files contain differing projections then this tool will still work as it will reproject one of the source files to the projection of the other source file.  Then the statistics comparison tools such as Scatter Plot can be used in the new file to compare any of the bands.

Topic Cropping .L3m Images Through Command Line By knowles Date 2020-06-02 16:13
Since your input file is a mapped file then with SeaDAS the best option for geographically cropping a file at the command line would be to use the gpt Subset operator.  See the GPT Cookbook within the SeaDAS 7.5.x GUI (Menu > Help > Cookbooks > GPT Cookbook).  Go to the section on the "Subset" operator and see Example 1.  This example will do what you want for a single file at the command line.

Note: you should also look at the "General Configuration and Options" section of the GPT Cookbook in order to set up the gpt alias to your respective gpt executable (platform dependent).

SeaDAS doesn't provide a multi-file crop/subset looping script specific to what you are trying to do, so you would need to write your own script.  In general that means putting a list of files in a text file, then using a scripting language such as python to read in that text file which contains the list of files, and executing the command line operation on each file, as the script loops through the list files.

Topic l2gen products By knowles Date 2020-05-22 15:07
As a note since SeaDAS 7 has a platform dependent gpt executable filename, I'm using "gpt" as an alias for convenience:

For example I have on my mac in the file ~/.profile:
export SEADASROOT=/Users/seadas/SeaDAS_Installations/seadas-7.5.3
alias gpt=$SEADASROOT/bin/gpt.command

Topic l2gen products By knowles Date 2020-05-22 14:44
Are you using SeaDAS Version 7.5.3?
Topic l2gen products By knowles Date 2020-05-22 11:01
I downloaded the file ( and ran it on my mac with no problem.

I used your graph file and the command line I used is:
gpt reproject.xml -f GeoTIFF -Ptarget=AQUA_MODIS.20071229T071507.L2.SST_reprojected.tif

I do see an "x" in your file name likely indicating an extract.  I don't believe this is the issue but to rule it out perhaps try running it on the unextracted file.

Topic l2gen products By knowles Date 2020-04-29 11:46
This is correct Amita.  If you save the file then the reprojection occurs for all bands.  As I mentioned, if you create a "virtual" file (not saved but just in the GUI) then the reprojection does not occur until you view the band.

Topic l2gen products By knowles Date 2020-04-27 14:13
In addition to possible memory allocation differences between the GUI and command line gpt run of Reprojection, the GUI run of Reprojection can be extremely fast if you choose to NOT save the target file.  In this GUI case, the target file is "virtual" and reprojection does not actually occur until a band of the target is actually viewed in the GUI, and even then reprojection only occurs in the target band being viewed, not the full file.

When running gpt, you might also choose to close the SeaDAS GUI application during the run for possible better use of the memory so as to not have 2 simultaneous instances of seadas going.

Topic command line OCSSW advice By knowles Date 2020-02-04 11:58
MSI and OLCI are not supported yet within the SeaDAS GUI, but can be done on the command line.  OCSSW works well on both Linux and Mac.  There is currently no tutorial on l2gen command line but some of the presentation slides give a broad overview of the l2gen features.

To install the MSI/OLCI processors run these commands:
./ --msis2a
./ --msis2b
./ --olcis3a
./ --olcis3b

From the command line your l2gen run might look something like this:
l2gen ifile={level1_input_file} ofile={level2_output_file} par=parfile.txt

where parfile.txt is an optional textfile you provide containing your desired parameters of the form:

You can run l2gen from the command line to see a listing of the parameters and defaults.  To get an idea of what this parfile might look like for your desired parameters, you could load MODIS into the l2gen GUI and export the parameter file.

Also you need to have your command line environment configured so you should put these lines in your startup file ~/.bashrc (Linux) or ~/.profile (Mac):

export OCSSWROOT=[SeaDAS_install_dir]/ocssw
source $OCSSWROOT/OCSSW_bash.env

Topic the color of images generated by SeaDAS By knowles Date 2019-10-10 14:17
Yes the colors do indicate the chlorophyll concentration.  To view the color bar (legend) of a particular image, right click on the image and select "Export Colorbar" or there is an shortcut icon in the menu bar.  The range (thresholds) can be adjusted in the Color Manager window.

I would recommend this tutorial case study.

Also this video is a good introductory video.

There are plenty of help resources here:

You can download java 8 here:

SeaDAS 7 does not support java versions later than java 8.  

Topic export a 'geometry' By knowles Date 2019-07-25 13:48
Profile plot is what you want for a line vector.  If for some reason you want to extract pixels of some other vector shape (such as polygon) or ROI (region of interest) masks then you could use the Pixel Extraction tool to do this.  Essentially placing a pin somewhere in the center of the ROI, choosing a huge box size to encompass your region, and then selecting the desired masking criteria. 

Topic marker color and shape? By knowles Date 2019-07-17 13:53
Once you have imported the CSV file as a vector into SeaDAS you can edit the color and shape of the markers. 

To do this go to the Layer Manager tool window.  Within this window select the layer associated with the CSV file (note: you select the layer to be the "active layer" by clicking on the layer name, if you toggle the checkbox you are just toggling the visibility of the layer within the image and not actually selecting the layer as selected).   You'll know it is selected when the layer name becomes highlighted in blue.

Next click on the "pencil" icon.  This will open the layer editor for the "active layer".  Then edit within this GUI, the shapes and colors of the markers.  This affects ALL points of the layer.

If you only wish to edit only a single point, then click on the selector (it's the arrow in the toolbar at the top) and this click on the point within the image which you wish to edit.  Then click on the pencil icon.  Now the layer editor is set to adjust that single point and not the full set of points.

Topic climatology By knowles Date 2019-06-25 08:43
"all the years combined" is a bit vague.  Are you trying to combine the level-3 annual composites or seasonal composites or something else or perhaps level-2 files?  If it is level-3 annual files then to avoid a seasonal or other bias don't use incomplete years (such as 2002 for Aqua).

Also note to aggregate a mean of multiple files you cannot use the MathBand tool to find the sum and divide by the number of files, as the number of valid pixels is dependent on each pixel.  The SeaDAS aggregation tool options for this purpose would be the OCSSW processors l2bin and l3bin.  There is also the more generalized GUI tools Mosaic and Level3 Binning.

Topic viirsj1 processing issues By knowles Date 2019-06-24 08:27
Try doing a full install of the processors with the clean option set.  I

Topic uninstall older version? By knowles Date 2019-06-12 08:02
Your error message is associated with a problem with your text file as addressed in your other parallel thread on this forum.

Regarding the installation:
If SeaDAS is installed in "/Applications/seadas-7.5.3" then the file "/Applications/seadas-7.5.3/VERSION.txt" should exist.  Are you sure SeaDAS is installed in "/Applications/seadas-7.5.3" ?

Does this file exist? "/Applications/seadas-7.5.3/config/seadas.config"

To determine where OCSSW is installed, what do you get from the command line if you type:
which l3bin

Topic Error using l3bin By knowles Date 2019-06-11 13:32
Did you test this new text file run of l3bin from the command line?   Your error still indicates something wrong with your text file such as the presence of an extra new line character.

To rule out the editor issue, can you try to generate your text file directly from the command line like this?

ls -1 /MY_FILES_DIR/A* >  /MY_FILES_DIR/files.txt

That command will generate a file "files.txt" containing a full path listing (1 file per line) of all files matching the pattern A*   Creating text files this way using a regular expression I find much simpler and quicker than using an editor.

Topic Error using l3bin By knowles Date 2019-06-11 11:06
If it runs from the command line and not the GUI then you either need to make the file list contain the full path name to the input files or you need to have the text file be located in the same directory as the input files. 

Topic multiple error using l3bin By knowles Date 2019-06-03 08:08
The error message indicates that it cannot find the first file in your list (and probably wouldn't find the rest as well).  If you are running from the command line then you either need the text file to contain the full directory path to each file or you need to run l3bin from within the directory which contains your input files.  If you are running from the GUI then you either need the text file to contain the full directory path to each file or the text file needs to be in the same directory as the input files because the GUI will run l3bin from within the directory which contains your input file (which in this case is your text file).

Topic Error using l3bin By knowles Date 2019-06-03 07:35
How about the other questions I asked like the OCSSWROOT environment variable and having 1 or 2 seadas directories?  We need to know this in order to understand what your error is.

Topic problems running MODIS and S3 processing By knowles Date 2019-05-31 10:49
To specifically include the git branch (in this case OCSSW branch v7.5 for SeaDAS version 7.5.x): -b v7.5 --aqua

Topic problems running MODIS and S3 processing By knowles Date 2019-05-31 09:58
Regarding setting paths for command line usage you can edit your ~/.bashrc file which gets run each time you launch a new terminal.  For instance mine currently contains these lines:

export SEADAS=/seadas/installations/7.5.3
export PATH=$SEADAS/bin:$PATH
export OCSSWROOT=$SEADAS/ocssw
source $OCSSWROOT/OCSSW_bash.env

Regarding the failure you either didn't install the Aqua processors or the installation failed? 

From your error message, you are missing these files which come with the Aqua installation:

For command line the installation for Aqua is: --aqua

Within the GUI it is menu: OCSSW > Update Data Processors
and then select the  aqua checkbox

The Time Series Tool is a very limited tool which geographically collocates multiple files using a Geographic Lat/Lon (platecarree) projection.  Unmapped files such as level2 files work as inputs.  But for level3 input files the mapping needs to be Geographic Lat/Lon.

this should work:
l3mapgen (resolution=4km, latnorth=+89, latsouth=+52, loneast=+67 and lonwest=+10)

Topic Error using l3bin By knowles Date 2019-05-30 10:22
You might have installed SeaDAS 7.5.3 in your existing directory which is named 7.5.2.   Though confusing, this wouldn't be a problem.   Do you have both a 7.5.3 directory and a 7.5.2 directory?

What is your environment variable $OCSSWROOT set to?  At command line type:

In the GUI, under Menu > OCSSW > Update Data Processors what is the "Local install-dir"

You posted dim files which require an associated data folder so they are not readable to forum users.

How exactly are you creating the level3 composite file?  Does the resultant level 3 file contain time information?   Within SeaDAS load the file and within the FileManager select the file, open the Metadata folder and select Global_Attributes.  What is in the temporal_range, and time_coverage_start field?  Or you can check whether SeaDAS recognizes the time info by looking at "Pixel Info" with the clock turned on.

This link is helpful if you haven't yet found what you need

Hi Amanda,

The land mask data of SeaDAS is around 1km resolution.  You can turn off the land masking by just adding proc_ocean=2 as one of your l2gen arguments.  This will force all pixels to be treated as ocean and there will be no land mask.  Alternatively you can do what you mentioned regarding assigning the null land mask.  It's the same effect.

The output is in fact georeferenced.  If you open the output level2 file in the SeaDAS GUI you can see the latitude and longitude bands and the fact that SeaDAS recognizes the geocoding.  Although the Landsat 8 data is actually mapped data, the fact that is it "mapped" is not recognized in the level2 output file.  l2gen treats all pixels as unmapped and provides the latitude and longitude individually for each pixel.

Regarding creating a high resolution land mask, the SeaDAS GUI does provide a 50m land mask so you could apply the higher resolution mask within the SeaDAS GUI.  This will create a land mask along with a band called "water_fraction".  You can then export the file (File > Export > NetCDF4-CF).   Note that the mask won't be exported but the water_fraction band will (0=water and 100=land).   If ArcMap requires a boolean band for masking, then within SeaDAS there is the Math Band Tool and you can create a land mask band with the expression "LandMask ? 1 : 0" making sure to deselect "Virtual" in the Math Band GUI.  This will create a band called something like "new_band_1" which you can rename to "landmask" if you wish via the Mask Manager GUI.

Also note that you could additionally crop/extract the file within SeaDAS GUI.

If ArcMap cannot recognize latitude and longitude bands and requires mapped data, then one option is that the SeaDAS GUI also provide a Reprojection Tool for mapping the data.

Note: if the GUI steps are useful to you and you need to do this on many files there are command line options using SeaDAS GPT (see Help > Cookbooks > GPT Cookbook)

Topic Error using l3bin By knowles Date 2019-05-16 07:24
There is a formatting problem with your text file.  See this thread for some suggestions:

Topic Landsat8 l2_flags By knowles Date 2019-05-08 07:41
1- It doest not give Rrs value in NIr band (865 nm)?
What do you mean?  If you mean that it doesn't generate the product Rrs_865 by default then this is correct.  The default for Rrs is Rrs_vvv which is all the visible bands and does not include Rrs_865.  You would need to specify Rrs_865 in the product list (l2prod).
2- can I process Landsat ETM+ data using L2gen?
Sorry, but no, currently l2gen only supports the OLI instrument for Landsat.

Topic Climate Standard By knowles Date 2019-03-06 12:41
The run button fails to be enabled whenever there is an unrecognizable file in the list or some extra hidden character is in the list.  Within the l3bin GUI, try selecting each of the files one at a time and see if the run button enables for each file.  Note that a blank line in the file will cause a problem as well.

Topic Climate Standard By knowles Date 2019-03-06 12:28
I cannot see your images.  So does this mean you could not do step1 which was also a text file run through l3bin.
Topic virus installation issues lots seadas 7.5 By knowles Date 2019-03-06 12:18
What is the full error message when it returns "file is not a valid input mission"?  There should be Mission=something at the end of the message.

You could also try to use the level1A file as the input file to l2gen.  I'm assuming you already have installed the VIIRS processors since you are using a level1B file which you must have processed from a level1A file.

Of note is that SeaDAS version 7.5.3 now supports VIIRS-J1.  You might try upgrading and it may fix your current problem as well. 

Topic Climate Standard By knowles Date 2019-03-05 07:50
What's the error?   To rule out a problem with your text file (which is a list of files) being incorrectly formatted you can instead try a single file to see if it works. 

Also the file name /Users/biancabroman/Desktop/Screen Shot 2019-03-04 at 4.11.29 PM.png contains spaces, perhaps this is causing your file upload problem.

Topic Climate Standard By knowles Date 2019-03-04 09:35
Here's a specific example which creates an aggregated "climatology" file for 2003-2005 using the June, July and August level3 monthly bin files as input.

Step 1a:
l3bin ifile=2003_monthlies.txt
where 2003_monthlies.txt:

Step 1b:
l3bin ifile=2004_monthlies.txt
where 2004_monthlies.txt:

Step 1c:
l3bin ifile=2005_monthlies.txt
where 2005_monthlies.txt:

Step 2:
l3bin ifile=2003_2005_summers.txt
where 2003_2005_summers.txt:

Note that you cannot actually make a "true" summer aggregated level3 file if your input is limited to monthlies.  For instance, the span of days when using June, July and August Monthly files for 2003 is from day 152 (June 1) to day 243 (August 31).  If you were to download the OBPG summer seasonal level3 file ( this actually spans from day 172 to day 263 (which is from June 21 summer solstice to September 20 autumn equinox).  In order to make a "true" summer file you could use the daily level3 files as your input to step 1.


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