I am trying to evaluate various algorithms to determine which is most effective in Lake Erie using Level 2 data.  I would like to include Carder's semi-analytic algorithm in my comparison, and I see that the c-code is available in SeaDAS, but I don't see where the necessary inputs are listed.  Where can I find the names of the input variables required to call the c-code from IDL?

Pamela,

SeaDAS uses a combination of IDL-code for the GUI and  C-code to assist
users conveniently realize L2 processing wtih various parameter selections.

Within SeaDAS GUI, user can easily choose from different models (Carder's,
GMS01, etc.) and compare those output with easy image display.

SeaDAS's help pages are good referenece for L2 processing programs.

   http://oceancolor.gsfc.nasa.gov/seadas/doc/msl12/msl12.html

Long

IOP models include:

gsm01 (Garver-Siegel-Maritorena semi-analytical)
Carder  (Carder Semi-Analyticall)
gaa      (Quasi-Analytical Algorithm)

Use Carder Semi-Analytical Bio-Optical Model can calculate products:

- adg_nnn_carder, absorption due to gelbstof and detrital material at sensor wavelength nnn
- chl_carder, chlorophyll concentration
- a_nnn_carder, total absorption at sensor wavelength nnn
- bb_nnn_carder, total backscatter at sensor wavelength nnn
. . .

adg_nnn_carder is one of IOP based products.

In SeaDAS command, we used to have an option:
iop_opt =[0-"None", 1-"Carder", 2-"GSM01", 3-"QAA"]

Not to confuse users who already selected products like:

      adg_412_carder, adg_443_carder, . . .        (carder model)
or   adg_412_gsm01, adg_443_gsm01, . . .       (gsm01 model)

Users don't have to re-select those model options, just
select product names will be good enough.

Long

All,

The option:

  iop_opt =[0-"None", 1-"Carder", 2-"GSM01", 3-"QAA"]

is a bit confusing.  In one run of msl12 you can generate IOP products from any or all of the bio-optical models we support.  The iop_opt does not effect that.  However, there are additional products for which IOPs (a and bb) are the input.  ZP Lee's spectral Kd algorithm is an example.  It is normally computed using IOPs from QAA, but you can choose to feed it IOPs from GSM01 or Carder.  We envision there will be other IOP-based algorithms in the future (products derived from IOPs rather than water-leaving reflectances or water-leaving radiances).

-- bryan

Long,
Does that mean that the GUI interface is the only option for implementing the Carder algorithm, and that the c-code cannot be called from an IDL program, even if the SeaDAS library has been downloaded on that computer?  I was under the impression that as long as the names of the inputs were listed with the name of the program being called, that IDL would be able to execute the code, even though it is written in C.
Pamela

You can use msl12 to implement the Carder algorithm via the GUI, the SeaDAS command-line, or the Unix command-line.

Using the SeaDAS or Unix command-line any msl12 product can be specified by way of the "l2prod1" parameter. The "iop_opt" parameter can also be used on either command-line.

Does this answer your question?

Hi,
How can I to fit with my filed data a semi-analytical algorithm (for example gms01 or carder) for my study area using Seadas? Is there a code or a command to do it?
Regards,
Carol

SeaDAS has no fitting function, but it comes with IDL which is a powerful analysis package for doing this type of thing. Using SeaDAS there are many ways to isolate satellite data that can then be used in any analysis package. The out_ascii and rline commands may be useful to you. There is also an example in the SeaDAS FAQ for accessing satellite data coincident to field data. The shiptrack GUI function may also be of use.

Do you have the code in IDL of the gsm01 algorithm e how can I to access its?
Regards
Carol

I've already found the code
Thanks anyway
Carol