Ocean Surface Salinity Validation in Canadian Waters

Transcription

1 Ocean Surface Salinity Validation in Canadian Waters Jim Gower, Institute of Ocean Sciences, Sidney, BC Élizabeth Simms, Memorial University, St-John s, NF Brenda Topliss, Bedford Institute of Oceanography, NS Irene Rubinstein, York University, ON Jim Helbig, Northwest Atlantic Fisheries Centre, NF Youyu Lu, Bedford institute of Oceanography, NS May Sixth SMOS Science Workshop Technical University of Denmark Lyngby, Denmark

2 VCOSS (or Google: VCOSS salinity ) Funded by the Canadian Space Agency Website hosted by Fisheries and Oceans Canada Reports: Microwave remote sensing in Canada Review of spaceborne and airborne experiments Sea surface salinity from space: a Canadian perspective Posters: VCOSS: Salinity from Space, the challenge VCOSS: Salinity from Space, the satellites O-Simms-AO

3 Virtual Centre for Ocean Satellite Salinity (VCOSS) Canadian organization with objectives: 1. To inform the space community about the oceanographic community s use of salinity data 2. To inform the oceans community about the status and progress of space programs that promise to deliver ocean salinity data. 3. To evaluate SMOS (and later, Aquarius) data in waters relevant to Canada. O-Simms-AO

4 Canadian Waters Influenced by low salinity runoff Seasonally ice covered Generally cold O-Simms-AO

5 Calibration and Validation Data Historical field data and ongoing results from ship and mooring measurements, particularly for northern waters Connections to the Canadian portion of the international Argo programme Connections to glider programs conducted by Canada Centre for Ocean Gliders and others. Satellite tracking of seals and other marine mammals, which is expected to provide CTD-quality data by 2007 Regional seasonal knowledge and in-situ measurements both in open ocean and coastal areas O-Simms-AO

6 Executive Summary Goal: Comparison of SMOS surface salinity data with data from conventional sources and models. Assessment of spatial and temporal variability Plan: Evaluate the section of the global SMOS products that fall within the area of waters of relevance to Canada, approximately 40 to 150 W and 40 to 75 N. Requirement from SMOS: Global data for comparison of errors for large areas, similar ocean regimes and errors near similar boundaries (coasts, ice) Requirement from VCOSS: Sufficient in-situ data to quantify errors in the initial SMOS data, monitor quality through mission, and assess effects of land and ice. O-Simms-AO

7 Approach Prime interest: Larger scale patterns: the Gulf Stream, Labrador Current, Gulf of Alaska. Smaller scale patterns: the sinking regions of the Thermohaline Circulation in the Atlantic and ENSO (El Nino) effects (Pacific) Exploratory: Impact of the near shore environment and the ice cover properties. Arctic Ocean and Hudson Bay In-situ data: Three-times annual Line P cruise in the eastern North Pacific, Annual cruise in the Labrador Sea (along the WOCE AR7W line), and Twice-annual Atlantic Zone Monitoring Programme (Scotian, Nfld Shelves) Argo, ocean gliders, tagged marine animals O-Simms-AO

8 56N, 50.5W BIO archive Salinity (ppt) Year O-Simms-AO

9 56N, 50.5W BIO archive Salinity (ppt) Year O-Simms-AO

10 Track of the Great Salinity Anomaly Belkin et al., Progress in Oceanography, 41, 1-68, 1998 O-Simms-AO

11 Station Papa 0.4 Salinity anomaly (ppt) y = x R 2 = Year Surface salinity at Station P (month averages with seasonal cycle removed), showing long-term freshening trend and confirmation of low recent values by Argo. O-Simms-AO

12 Station Papa Annual cycle: Argo 2001 to 2006, others 1956 to Salinity (psu) IOS harmonic WOA 98 Argo Tabata Marie Robert Year O-Simms-AO

13 ARGO profiling float array Argo is an international program that calls for the deployment of 3,000 free drifting profiling floats, distributed over the global oceans, which will measure the temperature and salinity in the upper 1,000 to 2,000 m of the ocean providing 100,000 T/S profiles and reference velocity measurements per year. This will allow continuous monitoring of the climate state of the ocean, with all data being relayed and made publicly available within hours after collection. As of May , about 2500 floats are in the water Argo is an element of: Global Climate Observing System (GCOS), Global Ocean Observing System (GOOS), Climate Variability and Predictability Experiment (CLIVAR), and Global Ocean Data Assimilation Experiment (GODAE). O-Simms-AO

14 Argo O-Simms-AO

15 Argo Positions of the floats that have delivered data within the 30 days preceding Apr 26, 2006 Source: O-Simms-AO

16 O-Simms-AO

17 Argo Buoys 2500 Number reporting Atlantic Ocean Pacific Ocean Indian Ocean Total Start of Year O-Simms-AO

18 Argo Pacific Jan 2001 to Mar 2003 Number of occurrences Shallowest depth (m) Distribution of shallowest depths for the roughly 11,000 profiles collected January 2001 to March 2003 in the Pacific. About 90% of shallowest measurements are from depths of 4 to 10 meters. O-Simms-AO

19 Ocean Gliders Profiling Argo floats with wings, allowing 30 o descent/rise angle from horizontal 3 manufacturers, producing 200 m ($US 70K) and 1000m ($US 125K) models Lithium batteries give 6 months operation, taking 8 hours per dive to 1000 m 540 dives, travelling 6 km along track each time, gives 3000 km range before recovery Data retrieval and command after each dive For SMOS, 200 m (or shallower) dives give more surface data, but limit range and may increase fouling O-Simms-AO

20 Seaglider record 663 dives, 24 Sept 2004 to 29 April 2005 O-Simms-AO

21 Seaglider tracks 7 Feb to 6 Jun 2005, Washington boundary currents O-Simms-AO

22 Seaglider dive #315 at 128W 24 May 2005 O-Simms-AO

23 Seaglider dive #269 at 125W 9 May 2005 O-Simms-AO

24 Days since Jan Surface salinity (PSU) from gliders, measured for about 1000 days (Aug 2003 to Mar 2006) depths 0-1 m, within 10 km of 47N, 128W. (C. Eriksen, Pers. Comm.: Rain events, annual cycle, increasing trend) O-Simms-AO

25 Annual range of surface salinity according to World Ocean Atlas Colour steps are 0.1 psu. Large areas have range <0.3 O-Simms-AO

26 Canadian Ocean Gliders The Canadian Centre for Ocean Gliders (Victoria, BC) have taken delivery of 4, 200 m gliders, but have not launched any yet. CCOG technical operation is in Newfoundland at the Institute for Ocean Technology Canadian Universities plan to buy 14 gliders. US groups have demonstrated operations in and near Canadian waters, including Baffin Bay and the Arctic O-Simms-AO

27 Tagged Marine Animals Tagging of Pacific Pelagics (TOPP) ( is collecting data using turtles, sharks and seals SEaOS program ( tracks southern elephant seals in the southern ocean Canadian east coast program (Contact O-Simms-AO

28 O-Simms-AO Salmon shark (red), elephant seals (green), leatherback turtles (white), loggerhead turtles (blue), blue shark (turquoise), mako shark (mauve)

29 TOPP Salmon shark tracks (no salinity data) O-Simms-AO

30 TOPP Elephant seals (three tags measured salinity) O-Simms-AO

31 SEaOS (Southern Elephant seals as Oceanographic Samplers) showing significant data contribution south of -60 (mostly temperature) O-Simms-AO

32 Canada east coast Data from tagged animals Canadian program has 136 tags, but only 3 for salinity Increasing numbers planned with higher fraction to be CTD Concentrated at surface May be concentrated near shore Adequate accuracy (0.05 psu, 0.05C, 5 m) O-Simms-AO

33 O-Simms-AO

34 ARGO vs Seals # of profiles deg BOX 80 ARGO Seals 40 0 Extensive Coverage by SEALS in the Gulf of St. Lawrence and Scotian Shelf (20,000 profiles) O-Simms-AO

35 VCOSS project Canadian Ocean Models West Coast and Pacific Institute of Ocean Sciences: P. Cummins, M Foreman. University of British Columbia: W. Hsieh. University of Victoria: A. Weaver Royal Military College: M. Stacey. East coast and Atlantic Bedford Inst. of Oceanography: D. Wright, Y. Lu, D. Brickman, J. Chasse, C. Hannah, C. Tang. Dalhousie University: R. Greatbatch, J. Sheng, K. Thompson Universite du Quebec a Montreal: F Saucier Department of Fisheries and Oceans, St. John's: F. Davidson, G. Han, University of Alberta: P. Myers Arctic Institute of Ocean Sciences: G. Holloway Canada Centre for Climate Modeling and Analysis: G. Flato Bedford Inst. of Oceanography: J. Greenberg, C. Tang Bedford Inst. of Oceanography, Institut Maurice Lamontagne and U. of Alberta (planned project) Gulf of St Lawrence Universite du Quebec a Montreal: F Saucier O-Simms-AO

36 VCOSS project Link to Aquarius Jim Gower is the Canadian representative on Aquarius, presently due for launch in July 2009, significantly later than the planned SMOS launch in March Comparison with Aquarius will be in ocean areas, where the two satellites are expected to provide relatively accurate data, and in coastal areas to investigate the different error mechanisms of the two sensors for land, ice and radio interference. Aim is to increase understanding data accuracy nearer shore and ice. O-Simms-AO

37 VCOSS project: Ice edge Sea Ice: maximum concentration March 5 (30yrs) O-Simms-AO

38 VCOSS project: Ice edge Sea Ice: Minimum concentration July 2 (30yrs) O-Simms-AO

39 VCOSS project: Anticipated results Investigate correspondence between expected and surfacemeasured sea surface salinity patterns and those observed with SMOS. Quantify sea surface salinity variation in Pacific and Atlantic Canadian waters (and possibly Arctic). Identify and characterize sea surface salinity patterns that were unknown before SMOS. Demonstrate the limits to deriving valid surface salinity data from SMOS near coasts or ice edges Provide a calibration data set for the long term monitoring of the instrument s radiometric performance. O-Simms-AO

40 Schedule 1. Evaluation of the large scale structure of the SMOS observation through comparison with seasonal or monthly climatology compiled from historical hydrographic data archives (6 months). 2. Evaluation of the spatial structure of the SMOS observation through comparison with coincident hydrographic surveys conducted in Canadian waters (Year 1). Possible surveys are: Three-times annual Line P cruise in the eastern North Pacific, Annual cruise in the Labrador Sea (along the WOCE AR7W line), and Twice-annual Atlantic Zone Monitoring Programme (Scotian, Nfld Shelves) 3. Assessment of the effects of land, ice and man-made and natural interference on SMOS observations (Year 2). 4. Evaluation of the time variability of SMOS observations where continuous in situ measurements of surface salinity are available (Year 2). 5. Comparison with Aquarius (Year 3?) O-Simms-AO