Up until recently we have received level 3 MODIS chlorophyll_a MO(Y)04MW26_chlor_a_2  and MO(Y)04MD26_chlor_a_2 products via subscription from the GDACC.  As of last week they have cancelled our subscription and sent us to the Ocean Color Web.  I have browsed your site and see that you offer Level 2 data via an FTP site and via subscription; however I still have a few questions.  Please forgive my unfamiliarity with your site and services.  I did search for answers to these questions, but did not quickly find what I needed to know.  Feel free to simply point me to pages on your site that provide the answers.

1) Are the Level 2  and level 3 files in the same HDF format I am used to getting from the NASA-EDG and MODIS Direct Broadcast providers?

2) At present I use the level 2 MO(Y)DOCQC files for geolocation.  Do you provide these files or equivilent?

3) Can I get specific level 2 MODIS products equivalent or similar to such products as the MO(Y)D02CLB and MO(Y)D02CLA products available from the EDG or DAAC? Are they available via ftp or subscription?

4) Do you offer the level 3 daily, 4-kilolometer, and parameter 26 (such as the MO(Y) 04MD26_chlor_a_2 or equivalent) via subscription or ftp - not requiring a manual order process?  If so, please point me to the source.

5) I have read past postings and see that other people are requesting that level 3 chl_a products be posted as soon as possible as opposed the present one week delay.  I too would like to stress the need for near real-time products even though they do not fit the stringent quality controls. Perhaps you can post "preliminary" chl_a products that come with a disclaimer. Even though they do not meet the levels of accuracy that the one-week old products do, the data are still quite valuable for ocean monitoring as opposed to historical research.

Thank you very much for your time.

Mark Hess

to answer your questions:

1) Are the Level 2 and level 3 files in the same HDF format I am used to getting from the NASA-EDG and MODIS Direct Broadcast providers?

they are indeed hdf format but in the same format as the past 7 years of seawifs data have been distributed.  most hdf tools will handle these files but most users work with the freely distributed package called seadas that you can download at http://seadas.gsfc.nasa.gov

2) At present I use the level 2 MO(Y)DOCQC files for geolocation. Do you provide these files or equivilent?

this is not needed since the level-2 files that are available from us are fully navigable within seadas without the need for an additional file.

3) Can I get specific level 2 MODIS products equivalent or similar to such products as the MO(Y)D02CLB and MO(Y)D02CLA products available from the EDG or DAAC? Are they available via ftp or subscription?

the current suite of level-2 products that are being produced is not the full complement that was previously produced and distributed by the goddard daac but there is a process in place to expand the current product suite through community working group recommendations.  the current products and a full description of the processing methodology can be found at:

http://oceancolor.gsfc.nasa.gov/DOCS/modis_processing_overview.pdf

http://oceancolor.gsfc.nasa.gov/ocformats.html

4) Do you offer the level 3 daily, 4-kilolometer, and parameter 26 (such as the MO(Y) 04MD26_chlor_a_2 or equivalent) via subscription or ftp - not requiring a manual order process? If so, please point me to the source.

all the level-3 files are available for ftp directly at:

ftp://oceans.gsfc.nasa.gov/Aqua_SMI/

from that directory you can decide which time periods, which spatial resolution and which parameters you want.  since the directory structure is fixed, you can automate the process from your end to retrieve the most recent data.

5) I have read past postings and see that other people are requesting that level 3 chl_a products be posted as soon as possible as opposed the present one week delay. I too would like to stress the need for near real-time products even though they do not fit the stringent quality controls. Perhaps you can post "preliminary" chl_a products that come with a disclaimer. Even though they do not meet the levels of accuracy that the one-week old products do, the data are still quite valuable for ocean monitoring as opposed to historical research.

i have to admit that i am really amazed that this is an issue because  before we assumed the responsibility for producing the ocean products from aqua/modis came along, there were no such things as near real-time global modis data products available at all.  i believe there were generally several days lapse between data acquisition and the availability of ANY data products.  we are currently making the global data available for download either on the web, via ftp or through a subscription at full resolution (1 kilometer) within 3 to 4 hours after aquisition by the satellite.  we are looking into the prospect of making a quick-look daily product but because of the nature of our data feed, there are most likely going to be holes in the product.  anyway, it is something we will try to do.
regards,
gene

Thanks for your quick reply.  As a commercial entity using Seawifs data operationally is cost-ineffective, so seadas was never necessary given the multitude of image processing packages available.  Since we do not use seadas, I'll have to investigate the HDF format used and how to extract the geolocation information and parameters I desire.   We run everything on HPUX workstations and PCs running Windows XP.  From what I can gather, we'd have to either set up a PC with Linux or purchase an SGI or Sun workstation (or port the code to one of our platforms).  Helpfully, the software we now use will support the SeaWifs HDF format.  

RE near real-time level 3 products: You are indeed correct, the Goddard DAAC did not provide near-real time level 3 ocean parameter products.  I have brought this matter up to that group and received a short "no plans to do this" as a response.  Since I saw a few other folks bring this topic up with your group, I thought I'd chime in and voice our desire to get these types of products quicker too.  The level 2 products are always an alternative, but the small file size and pre-processed nature of the level 3 chl_a product is very convenient

Kind Regards,

Mark