IOP Software Development

By bryan Date 2008-06-12 22:19

This is just a note to let everyone know what's been happening with the software and algorithm references that many of you provided.

We have been working to update and expand the suite of IOP algorithms that are available within the NASA level-2 processing code (msl12). The latest development version of msl12 now supports PML, Loisel & Stramski (LAS), and Hoge & Lyon (HAL), as well as updated QAA and unchanged GSM and Carder. In some cases the algorithms were previously integrated with msl12 by the algorithm developers, so the initial effort on our part was minimal.

A much larger effort has been to build a generic IOP model (GIOP) into msl12 to allow us to run large-scale sensitivity analyses on the satellite data. The GIOP model has a multitude of inputs to enable switching of functional forms and coefficients for the spectral relationships of aph, adg, and bbp, as well as the Rrs to R(0-) function. It also has the ability to switch between inversion methods (Levenburg-Marquart, Amoeba, LUDecomp, SVD). In addition we can control which set of sensor bands are used in the inversion. At present GIOP can reproduce GSM and HAL, and we can run either model parameterization using any of the inversion techniques.

Once we have a stable version of msl12 and complete more testing to verify implementations, we will make the code available to the group. For now, I just wanted you all to know where we were going.

-- bryan

By Silvia Romero Date 2010-06-18 19:36

Bryan,

I would like to get aph, adg and bbp from GSM and QAA models at 443.
I know I can get them from the L2 products
but at the time of choosing the processing options in seadas 6.1
do I have to select GSM and QAA again?

Another question..Is there any documentation I can read on the Misc. L2 product named CDOM_index?

Many thanks in advance,
best regards to you all,
Silvia

By bryan Date 2010-06-18 19:52

Silvia,

I'm not sure I understand the question. You can produce QAA and GSM products using l2gen in SeaDAS by processing level-1 data to level-2 and specifying (or selecting within the GUI) those products for output (e.g., aph_443_qaa, aph_443_gsm, ...).

The CDOM_index products is from:

Andre Morel, Bernard Gentili, A simple band ratio technique to quantify the colored dissolved and detrital organic material from ocean color remotely sensed data, Remote Sensing of Environment, Volume 113, Issue 5, 15 May 2009, Pages 998-1011, ISSN 0034-4257, DOI: 10.1016/j.rse.2009.01.008.

http://dx.doi.org/10.1016/j.rse.2009.01.008

By Silvia Romero Date 2010-06-18 20:03

Bryan,
thanks for the cdom_index citation.

When processing level-1 data to level-2 and specifying the products I want
I should also make decisions at the processing options window

what is the option that I should choose for "IOP model for use in downstream products"
None, GSM01, QAA ...

May be I do not understand what is meant by "downstream products".. aren't they aph, adg and bbp ?

By bryan Date 2010-06-18 20:14

This one confuses everybody, and I really don't know how else to say it. There are products such as Lee spectral Kd or euphotic depth that are derived from IOPs (inputs are a's and bb's). The iop_opt specifies which model to use when (internally) producing the IOP's for input to those IOP-based products. It has no effect on the output of IOP products.

--- bryan

By Silvia Romero Date 2010-06-20 15:46

Bryan,
thanks a lot. Sorry for my ignorance, but I prefered to ask before doing sth wrong..
best regards,
silvia