1、1Calibration and Validation of Ocean Color Products for Coastal WatersMarch 31-April 1, 2009CH2M Hill Alumni CenterOregon State University, Corvallis, OregonThis workshop addressed the issues of calibration and validation of ocean color products for coastal waters. It built on the results of an earl
2、ier workshop on the cross calibration of OCM and MERIS data with MODIS and SeaWiFS to extend the useful data sets for coastal monitoring. This workshop expanded the discussion to include protocols for the use of above-water and in-situ instrumentation and approaches for validation of products for th
3、e coastal ocean and related issues such as validating atmospheric correction for coastal locations. Workshop Objectives: 1. Address the issues of calibration and validation of ocean color products for coastal waters. 2. Build on the results of an earlier workshop on the cross calibration of OCM and
4、MERIS data with MODIS and SeaWiFS to extend the useful data sets for coastal monitoring. 3. Expand the discussion to include protocols for the use of above-water and in-situ instrumentation and approaches for validation of products for the coastal ocean and related issues such as validating atmosphe
5、ric correction for coastal locations. 4. The product of the workshop will be a set of recommendations for algorithms and approaches for validation of SeaWiFS, MODIS and MERIS and in the future the Hyperspectral Imager for the Coastal Ocean (HICO) and VIIRS coastal products, including atmospheric cor
6、rections relevant to coastal areas, recommendations for coastal validation site selection and use, and requirements for new instrumentation for coastal validation. 5. The long term goal is to develop a set of automated procedures for coastal product validation for all ocean color sensors.2Workshop A
7、genda and Notes with references to Presentations:March 31, 2009 Morning Day 1: coffee and continental breakfast 8:00 AM, meeting begins at 8:30AM Introductions and meeting overview (Davis, Arnone, Stumpf) Summary report of the first meeting (Davis, below)A Workshop on the use of MERIS and OCM by NAS
8、A, NOAA, Navy and university scientists was held at NRLSSC January 29-31, 2008. Current US ocean color sensors are past their design life and we need to assure continuity of data and products for ocean applications. Additionally MERIS and OCM are the only sensors designed for ocean color measurement
9、s at higher resolution that meet coastal requirements. The workshop focused on identifying issues that needed to be addressed to make use of MERIS and OCM data by US scientists for coastal waters with a goal of transitioning to operations. The workshop specifically addressed approaches for cross-val
10、idating MERIS and OCM-1 with coincident SeaWiFS and MODIS data and in-situ measurements.A primary result was a plan to assemble a comparison data set for 5 representative US coastal regions including MERIS, SeaWiFS and MODIS satellite data and in situ data for the sites for clear days in 2005 and 20
11、06. A plan was developed to process the data to a standard level for the comparisons at the remote sensing reflectance level and to compare a standard chlorophyll product and a standard product that estimates particulate scattering (Rrs 490 nm/ Rrs 560 nm). The data would be analyzed at full resolut
12、ion for comparisons to in-situ data, and it would be binned to a 4 km average for comparisons of large scale averages and temporal changes. The workshop participants were enthusiastic about the use of MERIS and OCM data for a host of science and operational applications. The 620 nm and 709 nm channe
13、ls on MERIS have proven especially useful to address issues of bathymetry of optically shallow waters and of harmful algal blooms in the Laurentian Great Lakes and coastal waters. Also the higher resolution of the MERIS 300 m data and the OCM data should be particularly valuable in many coastal regi
14、ons. For MERIS we need to demonstrate the utility of 300 m for operational coastal applications and the group plans to prepare a Cat 1 proposal to ESA for that work. We recognize that there is no mechanism in place for operational use of MERIS data at this time but the goal is to demonstrate the uti
15、lity of the data and develop products that can be used by US and other scientists and resource managers. The group also discussed the fact that OCM-1 may not be operating much longer, but that OCM-2 is due to be launched in 2009 and that it should provide better coverage and higher quality data. The
16、 group concluded that it was important to continue to work with OCM-1 to better understand the issues with this type of data and prepare for OCM-2 when it becomes available.3Therefore the group had two specific recommendations. First, US agencies (NASA, NOAA and Navy) should work with ESA for improv
17、ed access to 1.2 km and 300 m MERIS data. For MERIS we should request routine near-real time access to 1.2 km data for the Great Lakes, US coastal water and other areas of interest. The ideal would be to upgrade this to 300 m data for near coastal regions. Second, the group also expressed great inte
18、rest in receiving and working with OCM-1 data and OCM-2 data when it becomes available. The group considered that work with OCM-1 was essential as a pathfinder for OCM-2. We look to NOAA and NASA to make an agreement with the Indian Space Agency (ISRO) for access to that data. In return the US team
19、can share results and help with issues of calibration and data product validation that can help the Indian scientists make the best use of the data. MERIS, SeaWiFS and MODIS data comparisons: 3 hours Description of the combined MERIS, MODIS and SeaWiFS data set that was produced in response to the n
20、eed identified in the first workshop (Bailey_combined_dataset.pdf, parts 1 and 2) Presentations on comparison results and on current MERIS processing issues: Navy: (Lyon_MERIS_products.pdf) NOAA: (Foley_MERIS.pdf, Wang_MERIS.pdf) NASA: (Bailey_combined_dataset.pdf, section 3)Topics discussed by each
21、 group included: MERIS data used: source, processing methods and products Problems and issues Comparisons with SeaWiFS and MODIS: techniques and results Upgrade to MERIS L1 and L2 processing and MERIS data availability General Discussion of MERIS data and the approach for comparing/merging data from
22、 different ocean color sensors. (Stumpf moderator, Davis notes) 1 Hour MERIS data discussion:Processing to level 2 is a key issue:For NOAA and Navy applications MERIS needs to look like SeaWiFS and MODIS they need consistency because they blend products/image of the day (NAVY, NOAA use high res MERI
23、S data in specific areas, different than the GlobColour program which is looking at global averages) NASA, NAVY and NOAA propose to use L2GEN for processing of MERIS data: They have demonstrated some success so far, but there are many implications. Need to sort out L2GEN versions for MERIS processin
24、g (merge GSFC and NRLSSC versions); they are working together to accomplish this.L2GEN has choices of atmospheric models, etc. for MERIS processing, ultimately there should be a default processing scheme for MERIS similar to the default set up for MODIS. NASA is looking for agreement from ESA before
25、 releasing a version of L2GEN that includes MERIS in SeaDAS.We need to keep ESA informed of all of our work with MERIS data. 4In general the community would like to get full resolution MERIS data for US coastal waters. How do we get it? We need to improve connection with Canadian stations receiving
26、the data. Ultimately the 300 m data should come directly from Canada.A second issue is the archiving the data. (Only 2 weeks worth are maintained on the ESA website). To address this OSU will look at setting up an archive including data that has been collected to date. We must talk to ESA but we wil
27、l start to do this for MERIS CAT 1 users. (Letelier, Davis work with Paul Lyon, Dave Foley, Sean Bailey, Rick Stumpf)Immediately, send Dave Foley a list of west coast sites for collecting 300 m MERIS data.NRLSSC is collecting other sites; including GOM, MVCO, Chesapeake Bay.OSU to look at adding all
28、 of these to OSU archive? For coastal cal/val we need to relate the imagery to in situ data. Need to identify selected data sets for cal/val sites for MERIS, MODIS, SeaWiFS and other sensors.There was a discussion about the ESA processing for atmospheric correction. Several users noted differences i
29、n BEAM products and operational products. Using L2GEN and its associated atmospheric correction seems to produce a more consistent product, and one that is closer to the MODIS and SeaWiFS products for the same areas. Action items: Continue discussion of MERIS data using ocean color forum for MERIS (
30、Bailey), or if that is not possible at an OSU website (Letelier) Dave Foley to collect west coast sites; users should send Dave your site information. Sherwin Ladner will collect a list of east and gulf coast sites. OSU will set up an archive for the MERIS 300 m data as it becomes available for U.S.
31、 coastal waters. For now the site will only be open to MERIS CAT 1 team members. Release of L2GEN for MERIS? NASA and Navy will make available to their Cat 1 user community for evaluation and wait for ESA approval before wider release. Coast Watch to look into implementing APS including for MERIS pr
32、ocessing?Afternoon March 31, 2009 Lunch Coastal validation data sets (how they fit into coastal validation strategy): 3.0 hours NASA: SeaBASS/NOMADS other cal/val data (Bailey_combined_dataset.pdf, sections 5 and 6) NOAA: MOBY and Chesapeake Bay (Ondrusek_Cal-Val.pdf) OSU HOTS, and data from the coa
33、sts off Oregon and Chile (Letelier_OSU_in_situ_optics.pdf) USC selecting a SeaPRISM site for the west coast, (Jones_SeaPRISM_site_selection.pdf)5 CUNY SeaPRISM site and other measurements (Ahmed_SeaPRISM_optics.pdf) Topics discussed by each group: Instruments, calibration, protocols Water quality an
34、d coastal atmospheric conditions at their site Data storage and distribution In situ vs. satellite data matchups and statistics Automation of match ups Future Cruise programs: Letelier, others? Discussion of data requirements for validation of coastal products (Davis): 1 hourDiscussion of data requi
35、rements for coastal validation: Minimum data for validation of normalized water leaving radiances (nlw) or Remote Sensing Reflectances (Rrs):A SeaPRISM which operates continuously and unattended and produces both the aerosols and Rrs is preferred because the satellite makes this measurement (However
36、 we prefer a hyperspectral measurement so that we can match the data to all the satellite sensors.)Other above water systems include the MicroSAS (used routinely from a ferry by Barney Balch), and the HyperSAS which could provide the full spectra data. These systems do not measure the aerosols and a
37、re not designed for long-term continuous operation. Another system that provides full spectral data from below the water is the HyperPRO which can be used to collect vertical profile information, needed to propagate Rrs through the sea surface. A set of HyperPROs at OSU, NRLSSC and other sites shoul
38、d be cross calibrated for use in the coastal cal val activities.Other well calibrated in-water radiometers should be considered if the calibration and operation procedures are appropriate for cal val activities. A major issue is the spatial temporal variations in coastal waters making it difficult t
39、o relate in situ point measurements to satellite pixels on the order of 0.1 to 1 sq km. Rick Stumpf suggested we need to study this and how to evaluate it.It is essential to do this right to get one point that matches with the satelliteIn addition, we need to address the aerosol variability for the
40、same time and area. Sean Bailey admonished us to look at what you have from the satellite; only a 15% return of good data because of loss due to clouds, glint, etc.Time variations are also critical: we need to track tidal motions, etc to track the features.Time series data from moorings and gliders
41、is helpful. A practical approach may be to use coastal models to track the coastal dynamics. A related question was how do we distribute the samples in the ocean to best sample the variability in time and space?Minimum data set to validate bio-optical algorithms:The most direct conversion from the s
42、atellite measured Rrs is to spectral Inherent Optical Properties (IOPs). So in situ measurements of spectral a, c and bb at several bands is essential. 6Chlorophyll is a widely used product so Chlorophyll (by HPLC) used directly or to calibrate fluorescence chlorophyll measurements is essential? Nee
43、d to collect HPLC samples each time that you take HyperPRO or other in situ optical data. We should also tap other sources of quality chlorophyll which is widely measured. Weather information including SST, air temperature, wind speed, air pressure should be routinely measured as these are essential
44、 for atmospheric correction.Other issues considered:We should have one or more sites in optically shallow waters.We also discussed planned future in situ data collections:NRLSSC; Monterey Bay, CA, and the Alboran SeaOSU to continue collections on the Oregon coast, Chile-Peru coast and HOTSNOAA to co
45、ntinue collections on Chesapeake Bay; they can do rapid response sampling in Chesapeake as needed.Other investigators (need to make contacts, also look at SeaBASS data sets) Adjourn 5 PM *Morning April 1, 2009 Day 2: coffee and continental breakfast 8:00 AM, meeting begins at 8:30AM Brief presentati
46、ons on the status of: GOCI (Davis_GOCI.pdf) COIS (Davis) the Coastal Ocean Imaging Spectrometer (COIS) was originally developed for the NEMO program. NRL (Corson) continues to present it for the DoD Space Experiment Board who prioritizes missions for the Space Test Program (STP). COIS remains high (
47、5 of 62) on the STP list and NRL is still looking for a flight opportunity for COIS. One option is to revive the plan to fly it on NPOESS C1 platform. NRL is having informal discussions with the IPO on this possibility. OCM 2 (DiGiacomo_foreign_satellites.pdf presented by Davis) OCM 2 on Oceansat-2
48、satellite is presently scheduled for launch at the end of April but (perhaps summer?); see http:/www.ioccg.org/news/March2009/news.html Discussions are currently underway between ISRO, NASA and NOAA as to potential collaborations. However, it is not clear at this time that there will be a provision
49、for timely, free discussions are continuing in advance of the upcoming launch. As such NOAA NESDIS/STAR plans still TBD. Sentinel 2 (DiGiacomo_foreign_satellites.pdf presented by Davis) Apparently both Sentinel 3A and 3B have now been approved; the launch of Sentinel 3A is anticipated to take place no earlier than Q4 2012. 7NESDIS-STAR/OSDPD via CoastWatch (Central Ops & Nodes) plans to build upon the current MERIS
