NOAA Coral Reef Watch Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km Satellite Coral Bleaching Alert Area Product

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
NOAA Coral Reef Watch Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km Satellite Coral Bleaching Alert Area Product
Abstract:
The NOAA Coral Reef Watch (CRW) Enhanced 50-km (E-50) Satellite Coral Bleaching Alert Area product is part of the CRW experimental near-real-time global Enhanced 50-km (E-50) satellite coral bleaching thermal stress monitoring product suite that enhances the CRW operational near-real-time global 50-km satellite coral bleaching thermal stress monitoring product suite. The enhanced (E-50) product suite was launched on September 30, 2009. Its counterpart, the operational product suite, was implemented initially in 2000. Both product suites provide updated monitoring information twice-weekly. This metadata file provides information on the E-50 Bleaching Alert Area product for both the most recent near-real-time updates and the archived E-50 Bleaching Alert Area product, dating back to October 2007, when the E-50 Bleaching Alert Area product first became available. The satellite Bleaching Alert Area identifies, for the twice-weekly time period ending on the day indicated in the product, locations where thermal stress reaches various levels that can lead to coral bleaching. A scale of five coral bleaching thermal stress levels - No Stress, Bleaching Watch, Bleaching Warning, and Bleaching Alert Levels 1 and 2 - is used. The thermal stress classification is described in detail at the operational Bleaching Alert Area webpage: <http://coralreefwatch.noaa.gov/satellite/baa.php>. Both the Bleaching Alert Area and the level of stress defined by the product are derived from CRW's Coral Bleaching HotSpots and Degree Heating Weeks (DHW) values, measured at each site for any given twice-weekly time period. The DHW product (a key tool in both CRW's operational and E-50 coral bleaching monitoring product suites) measures accumulation of bleaching thermal stress that coral reefs experience over a period of 12 consecutive weeks (about 3 months), ending on the day indicated in the DHW product. The DHW product is derived from the Coral Bleaching HotSpots product (another key tool in the CRW product suites). A Coral Bleaching HotSpot is a specific type of sea surface temperature (SST) anomaly that measures the amount of SST exceeding a static coral bleaching threshold SST; it serves as a measure of instantaneous bleaching thermal stress and shows the occurrence, magnitude, and spatial distribution of the stress. All non-positive HotSpot values are recorded as zeros. The DHW value (again, a measurement of accumulated thermal stress) is, in its most simplistic form, the sum of all of the individual twice-weekly HotSpot values at any particular location, within a 12-week period and with a magnitude of at least 1 degree Celsius, multiplied by the duration of the twice-weekly HotSpot value (i.e., 0.5 weeks). A more complicated formula describing how the DHW value is calculated can be obtained at: <http://coralreefwatch.noaa.gov/satellite/methodology/methodology.php#dhw>. One DHW is equivalent to one week of SST at 1 degree Celsius above the threshold, or 0.5 weeks of SST at two degrees Celsius above the threshold. CRW's E-50 HotSpots product that CRW's E-50 DHW and E-50 Bleaching Alert Area are derived from is calculated from CRW's E-50 SST, based on near-real-time satellite data from the Advanced Very High Resolution Radiometer (AVHRR) on some of NOAA's Polar Orbiting Environmental Satellites (POES), as with the operational SST. CRW's entire experimental E-50 satellite coral bleaching thermal stress monitoring product suite is based on the enhanced 50-km SST product. The E-50 HotSpots and E-50 DHW products, as well as the resulting E-50 Bleaching Alert Area products, provide two major improvements over the current operational 50-km DHW and Bleaching Alert Area products: full coastal coverage and improved climatology. The E-50 SST product that the entire E-50 product suite is based on produces SST data for areas closer to the coast globally. This is achieved through the use of a higher-resolution land mask and retrieval of satellite data in coastal regions excluded from analysis by the operational land mask. Availability of satellite data for coastal areas greatly improves monitoring of coral reef ecosystems, the majority of which occur along coasts. While the current operational SST product enables direct monitoring of only 40% of the world's coral reefs, this E-50 SST product uses the new 50-km land mask to provide SST monitoring for more than 99% of 50-km pixels that contain coral reefs globally. CRW's operational HotSpots that the operational DHW and Bleaching Alert Area products are derived from, are sensitive to errors in the climatology (long-term average conditions) used in the analysis. The E-50 climatology, used to develop the E-50 product suite, improves the overall accuracy of CRW products. It uses the 1985-2006 Version 5.0 Pathfinder 4-km AVHRR SSTs to address known climatology errors in CRW's operational 50-km product suite. Errors include overestimation of the operational 50-km HotSpots, DHW, and Bleaching Alert Area in certain regions, such as the Gulf of Panama and Gulf of Oman. Related details, as well as other important information, are provided on the E-50 portion of the CRW web site: <http://coralreefwatch.noaa.gov/satellite/e50/index.php>. The E-50 Bleaching Alert Area product is available in static image and Google Earth formats. The product, its detailed description, and available data formats and delivery mechanisms are accessible at <http://coralreefwatch.noaa.gov/satellite>, along with general CRW product information and access to other CRW products.
Supplemental_Information:
The entire suite of products mentioned in this metadata file is accessible at: <http://coralreefwatch.noaa.gov/satellite>
  1. How should this data set be cited?

    NOAA Coral Reef Watch program, 20071011, NOAA Coral Reef Watch Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km Satellite Coral Bleaching Alert Area Product: NOAA Coral Reef Watch program, Silver Spring, Maryland, USA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -180.0
    East_Bounding_Coordinate: 180.0
    North_Bounding_Coordinate: 45.0
    South_Bounding_Coordinate: -45.0

  3. What does it look like?

    <http://coralreefwatch.noaa.gov/satellite/e50/current/e50_baa_45ns.current.gif> (GIF)
    This is the most recent image of NOAA CRW Experimental near-real-time twice-weekly global Enhanced 50-km satellite Coral Bleaching Alert Area product.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 11-Oct-2007
    Ending_Date: Present
    Currentness_Reference: Ground Condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Remote sensing image, KML, Google Earth, webpage

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 331 x 720, type Grid Cell

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.5. Longitudes are given to the nearest 0.5. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    Grid Intersection
    There are 720 grid intersections in each row (at a pre-defined latitude) and 331 grid intersections in each column (at a pre-defined longitude). Each grid is 0.5 degree latitude by 0.5 degree longitude in size, centered at latitudes of from 80.0S northward to 85.0N and at longitudes of from 180W eastward to 179.5E. (Source: <http://coralreefwatch.noaa.gov/satellite/methodology/methodology.php>)

    E-50 Bleaching Alert Area image files in GIF format
    These are the image displays of original coral Bleaching Alert Area data. (Source: <http://coralreefwatch.noaa.gov/satellite/e50/index.php>)

    Range of values
    Minimum:0
    Maximum:255
    Units:Index color values


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    NOAA Coral Reef Watch program
    Attn: NOAA Coral Reef Watch Coordinator
    NOAA, E/RA31, SSMC1, Room 5308, 1335 East-West Highway
    Silver Spring, Maryland 20910-3226
    USA

    301-713-2857 ext 109 (voice)
    301-713-3136 (FAX)
    coralreefwatch@noaa.gov


Why was the data set created?

The NOAA Coral Reef Watch program seeks to fully utilize space-based sea surface temperature (SST) observations, combined with in-situ data, to continually monitor for early indications of thermally-induced coral reef bleaching worldwide. A suite of monitoring and prediction products, including the product described in these metadata, has been developed by CRW as a decision support system to provide critical and timely coral reef environment information to the U.S. and international coral reef communities.


How was the data set created?

  1. From what previous works were the data drawn?

    NOAA CRW Near-Real-Time Global Enhanced 50-km satellite coral bleaching Degree Heating Weeks Product (source 1 of 3)
    NOAA/NESDIS Coral Reef Watch program, 20071011, NOAA CRW Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km satellite coral bleaching Degree Heating Weeks: NOAA Coral Reef Watch program, Silver Spring, Maryland, USA.

    Type_of_Source_Media: data file
    Source_Contribution:
    The E-50 Bleaching Alert Area product was derived from this E-50 coral bleaching Degree Heating Weeks product.

    NOAA CRW Near-Real-Time Global Enhanced 50-km Satellite Coral Bleaching HotSpots Product (source 2 of 3)
    NOAA/NESDIS Coral Reef Watch program, 20071011, NOAA CRW Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km Satellite Coral Bleaching HotSpots: NOAA Coral Reef Watch program, Silver Spring, Maryland, USA.

    Type_of_Source_Media: data file
    Source_Contribution:
    The E-50 Bleaching Alert Area product was derived from the E-50 Coral Bleaching HotSpots product.

    NOAA CRW Near-Real-Time Global Enhanced 50-km Satellite Sea Surface Temperatures (source 3 of 3)
    NOAA/NESDIS Coral Reef Watch, 20071011, NOAA CRW Experimental Twice-Weekly Near-Real-Time Global Enhanced 50-km Satellite Nighttime Sea Surface Temperatures: NOAA Coral Reef Watch program, Silver Spring, Maryland, USA.

    Type_of_Source_Media: data file
    Source_Contribution:
    The E-50 Bleaching Alert Area, Degree Heating Weeks, and HotSpots products were derived from this E-50 SST product.

  2. How were the data generated, processed, and modified?

    Date: Not complete (process 1 of 1)
    The level of coral bleaching thermal stress at a data grid presented in the Bleaching Alert Area product is determined by the values of Degree Heating Weeks and HotSpots at the data grid. A Degree Heating Week is calculated as the accumulation of Coral Bleaching HotSpots over 12 consecutive weeks. At each pixel, a coral bleaching threshold SST value is subtracted from the SST value to produce the Coral Bleaching HotSpot. See the CRW web site at <http://coralreefwatch.noaa.gov/satellite/index.php> and suggested references listed above for details.

    Person who carried out this activity:

    NOAA Coral Reef Watch program
    Attn: NOAA Coral Reef Watch Coordinator
    NOAA, E/RA31, SSMC1, Room 5308, 1335 East-West Highway
    Silver Spring, Maryland 20910-3226
    USA

    301-713-2857 ext 109 (voice)
    301-713-3136 (FAX)
    coralreefwatch@noaa.gov

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The accuracy of both the E-50 and operational Bleaching Alert Area product depends on the accuracy of CRW's Degree Heating Weeks (DHW) and Coral Bleaching HotSpots products, which, in turn, depend on the accuracy of satellite SSTs and bleaching threshold SSTs. A full evaluation and validation of CRW's E-50 and operational HotSpots, DHWs, and the classification of the five bleaching thermal stress levels have not been completed yet. A preliminary evaluation revealed, however, that these products demonstrate remarkable success in detecting, monitoring, and predicting all large spatial scale mass coral bleaching events. Polar Orbiting Environmental Satellite (POES) AVHRR-SST values used for creating CRW 50-km SST analysis fields were accurate to within 0.5 degree Celsius and adjusted by in-situ buoy observations to best-approximate SST at the depth of one meter. However, when producing a complete, gap-filled SST analysis with global coverage, estimation of SST at the pixels covered by cloud may occasionally reduce the accuracy of SST at these pixels.

  2. How accurate are the geographic locations?

    Users are referred to the following guide on AVHRR-derived sea surface temperature: Goodrum, G., K.B. Kidwell, and W. Winston, 2000, NOAA KLM USER'S GUIDE. U.S. Department of Commerce, National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service, National Climatic Data Center, Climate Services Division, Satellite Services Branch, FOB3, Room G227, E/CC33, 5200 Auth Road, Suitland, MD 20746-4304, USA. This manual is available on line at: <http://www2.ncdc.noaa.gov/docs/klm/cover.htm>. To request additional information, contact: Telephone: (828) 271-4850, Telefax: (828) 271-4876, Email: satorder@ncdc.noaa.gov.

  3. How accurate are the heights or depths?

    none

  4. Where are the gaps in the data? What is missing?

    There is no spatial data gap existing in this data set. No change will be made to the original Bleaching Alert Area data, but occasional revisions to some images may occur if an inaccuracy is detected in the image display of the data. New near-real-time Bleaching Alert Area products will be added continuously to these data at scheduled update times. The Bleaching Alert Area product has not been produced retrospectively back to 2000 to match the full time series of HotSpots and Degree Heating Weeks products. In addition, animation and HDF data formats have not been implemented yet for the Bleaching Alert Area product. Retrospectively processed data and new data formats will be available soon on the CRW web site.

  5. How consistent are the relationships among the observations, including topology?

    none


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
Use_Constraints:
Not intended for legal use. Data may contain inaccuracies due to cloud cover and/or other reasons.

  1. Who distributes the data set? (Distributor 1 of 1)

    NOAA Coral Reef Watch program
    Attn: NOAA Coral Reef Watch Coordinator
    NOAA, E/RA31, SSMC1, Room 5308, 1335 East-West Highway
    Silver Spring, Maryland 20910-3226
    USA

    301-713-2857 ext 109 (voice)
    301-713-3136 (FAX)
    coralreefwatch@noaa.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 26-Jul-2013
Last Reviewed: 26-Jul-2013
Metadata author:
NOAA Coral Reef Watch program
Attn: NOAA Coral Reef Watch Coordinator
NOAA, E/RA31, SSMC1, Room 5308, 1335 East-West Highway
Silver Spring, Maryland 20910-3226
USA

301-713-2857 ext 109 (voice)
301-713-3136 (FAX)
coralreefwatch@noaa.gov

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.13 on Sun Dec 28 10:42:29 2014