The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501)

The Coral Reef Temperature Anomaly Database (CoRTAD) is a collection of sea surface temperature (SST) and related thermal stress metrics, developed specifically for coral reef ecosystem applications but relevant to other ecosystems as well. The CoRTAD Version 2 contains global, approximately 4 km resolution SST data on a weekly time scale from 1982 through 2008. It is related to the CoRTAD Version 1 (NODC Accession Number 0044419), with a few important differences. Whereas Version 1 covers the time period from 1985-2005, Version 2 contains 6 additional years of data, extending that period to 1982-2008. Also, whereas Version 1 is in HDF4 Scientific Data Set format, Version 2 is in HDF5 format.

In addition to SST, the CoRTAD contains SST anomaly (SSTA, weekly SST minus weekly climatological SST), thermal stress anomaly (TSA, weekly SST minus the maximum weekly climatological SST), SSTA Degree Heating Week (SSTA_DHW, sum of previous 12 weeks when SSTA >= 1 degree C), SSTA Frequency (number of times over the previous 52 weeks that SSTA >= 1 degree C), TSA DHW (TSA_DHW, also known as Degree Heating Week, sum of previous 12 weeks when TSA >= 1 degree C), and TSA Frequency (number of times over previous 52 weeks that TSA >=1 degree C). The CoRTAD was created at the NOAA National Oceanographic Data Center in partnership with the University of North Carolina - Chapel Hill, with support from the NOAA Coral Reef Conservation Program.

The purpose of the CoRTAD is to provide sea surface temperature data and related thermal stress parameters with good temporal consistency, high accuracy, and fine spatial resolution. The CoRTAD is intended primarily for climate and ecosystem related applications and studies and was designed specifically to address questions concerning the relationship between coral disease and bleaching and temperature stress.
  • Cite as: Casey, Kenneth; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2011). The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501). Version 1.1. National Oceanographic Data Center, NOAA. Dataset. [access date]
gov.noaa.nodc:0054501
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  • HDF (Version: 5)
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Distributor DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
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DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Time Period 1982-01-01 to 2008-12-31
Spatial Bounding Box Coordinates
N: 90
S: -90
E: 180
W: -180
Spatial Coverage Map
General Documentation
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  • Descriptive Information
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Associated Resources
  • New insights into global patterns of ocean temperature anomalies: implications for coral reef health and management
Publication Dates
  • publication: 2011-01-20
Edition 1.1
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Data Update Frequency As needed
Supplemental Information
[Text below adapted from: Selig, Elizabeth R., Kenneth S. Casey, and John F. Bruno (2009), New insights into global patterns of ocean temperature anomalies: implications for coral reef health and management, Global Ecology and Biogeography, in press. Hereafter referred to as "SCB2009".]

The CoRTAD was developed using data from the Pathfinder Version 5 collection produced by the National Oceanic and Atmospheric
Administration's (NOAA) National Oceanographic Data Center (NODC) and the University of Miami's Rosenstiel School of Marine and Atmospheric Science (http://pathfinder.nodc.noaa.gov). These sea surface temperature data are derived from the Advanced Very High Resolution Radiometer (AVHRR) sensor and are processed to a resolution of approximately 4.6 km at the equator. These data have the highest resolution covering the longest time period of any satellite-based ocean temperature dataset (see Figure 1 of SCB2009). Weekly averages of day and night data with a quality flag of 4 or better were used, which is a commonly accepted cutoff for "good" data (Kilpatrick et al., 2001, Casey and Cornillon, 1999). By using a day-night average, the number of missing pixels was reduced by 25% with virtually no loss in accuracy (see Table 2 of SCB2009).

The Pathfinder algorithm eliminates any observation with a Sea Surface Temperature (SST) more than 2 degrees C different from a relatively coarse resolution SST value based on the Reynolds Optimum Interpolation Sea Surface Temperature (OISST version 2.0)* value, a long-term, in situ-based data set (Kilpatrick et al., 2001, Reynolds et al., 2002). Observations were added back into the analysis if the SST was greater than the OISST-5 degrees C, but less than the OISST+5 degrees C. The 5 degrees C threshold is a reasonable selection that allows diurnal warming events (Kawai and Wada, 2007) or other spatially limited warm spots back into the dataset without including unrealistic and erroneously warm values. Values less than the OISST were not included because they may have been biased by cloud contamination and other satellite errors, which tend to result in cooler SST estimates. These processes resulted in a dataset with only 21.2 percent missing data. To create a gap-free dataset for analysis, 3 x 3 pixel median spatial fill was used. A temporal fill was performed using the Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) function in Matlab (The Mathworks Inc., 2006) to fill the remaining gaps. This conservative approach was chosen because it provided interpolated SSTs that are bounded by the nearest available values in time. It also used data from only a very limited spatial domain, which is an important consideration given the variability of coral reef environments.

[*NOTE: The higher resolution Reynolds 25km Daily Optimum Interpolation Sea Surface Temperature (DOISST version 2.0) dataset was used in place of the OISST version 2.0 for the Pathfinder data from 1982-1984. The primary effect of this change is to retain more data in the high gradient regions and in regions where meandering or feature advection is present; effect on the retrieved SST is minimal.

Two problems with the original Pathfinder data from 1982-1984 have been identified. An error was discovered in the processing of the reference SST fields, which created a "halo" of cold pixels around coastlines in the reference field. As a result, several anomalously cool Pathfinder SST pixels have passed the reference test during processing and been assigned quality flag values that are too high. The second problem arises from the fact that the reference SST field used for 1982-1984 data lacks inland SST observations. As a result, the gap-filling routine employed by the CoRTAD fails for inland pixels for the entire 1982-1984 period. In order to avoid contamination of climatology-based thermal metrics and statistics calculated in the CoRTAD, all data from 1982-1984 were omitted from the climatology. Thus, the CoRTAD Version 2 climatology was calculated using only 1985-2008 data. All CoRTAD fields have been calculated for the entire time series (1982-2008) based on this climatology. For an image demonstrating these problems in Pathfinder processing, please see the "Known Problems" section of the Pathfinder Version 5 User Guide at http://pathfinder.nodc.noaa.gov/userguide.html.]

Using these gap-filled data, we then created site-specific climatologies for each reef grid cell to describe long-term temperature patterns over the 21-year dataset (Eqn. 1). The climatology was generated using a harmonic analysis procedure that fits annual and semi-annual signals to the time series of weekly SSTs at each grid cell:

climSST(t) = A*cos(2pi*t + B) + C*cos(4pi*t + D) + E (1)

where t is time, A and B are coefficients representing the annual phase and amplitude, C and D are the semi-annual phase and amplitude, and E is the long-term temperature mean.

Similar approaches have been used for generating climatologies because they are more robust than simple averaging techniques, which can be more susceptible to data gaps from periods of cloudiness (Podesta et al., 1991, Mesias et al., 2007).

Sea surface temperatures from AVHRR quantify only the temperature of the 'skin' of the ocean, roughly the first 10 micrometers of the ocean surface (Donlon et al., 2007). Most field surveys of coral cover occur between 1 and 15 m depth. To be useful for coupling with coral reef biological data, these temperature data must be relatively accurate beyond the 'skin' of the ocean. Linear regression was used to examine how data from in situ reef temperature loggers compared with data from the CoRTAD to demonstrate the good accuracy of the CoRTAD temperature data compared to in situ data at a variety of depths and locations around the world (see Table 2 of SCB2009 for details).


Temperature anomaly metrics:

Several metrics could be used to link coral reef ecosystem health with temperature including trophic structure, diversity or percent coral cover (Newman et al., 2006, Roberts et al., 2002, Bruno and Selig, 2007). However, this analysis focused on coral bleaching and disease because they are key drivers of coral decline and their relationships with temperature patterns are better understood (Aronson and Precht, 2001, Bruno et al., 2007, Glynn, 1993). Analyses were performed on two metrics (see Table 1 of SCB2009): one that is commonly known to lead to bleaching (Liu et al., 2003, Strong et al., 2004, Glynn, 1993), and one that is correlated with increased disease severity (Selig et al., 2006, Bruno et al., 2007). Coral bleaching results when corals lose their symbiotic zooxanthellae (Glynn, 1993, Glynn, 1996). Bleaching is a natural stress response not only to warm temperatures, but also to cool temperatures (Hoegh-Guldberg and Fine, 2004) as well as light and salinity values different from the normal range (Glynn, 1993). Corals can recover from bleaching, but their ability to do so is dependent on the magnitude and duration of the anomaly event (Glynn, 1993). The temperature thresholds that result in coral bleaching vary by
location and species (Berkelmans and Willis, 1999). Bleaching is often connected to Thermal Stress Anomalies (TSAs), which are defined as areas where temperatures exceed by 1 degree C or more the climatologically warmest week of the year (Table 2, Glynn, 1993). The temperature anomaly thresholds relevant to disease have been studied in only one pathogen-host system (Selig et al., 2006, Bruno et al., 2007). In that system, changes in disease cases were correlated with Weekly Sea Surface Temperature Anomalies (WSSTAs), temperatures that were 1 degree C greater than the weekly average for that location. The best metric for predicting bleaching or disease may vary according to location, species, and pathogen (Selig et al., 2006, Bruno et al., 2007, Berkelmans, 2002). For example, bleaching on the Great Barrier Reef was best predicted by the maximum anomaly over a 3 day period (Berkelmans et al., 2004), rather than an anomaly metric like the TSA. Although the 7-day averaging approach in the CoRTAD may be too temporally coarse to capture all bleaching events, it is necessary to maintain consistency and minimize gaps in the dataset across broad spatial scales. In addition, the data are less likely to yield false positives for TSAs and will likely capture most WSSTA events, which have a lower temperature threshold.

References: (see SCB2009 for complete list)
Purpose To provide sea surface temperature data and related thermal stress parameters with good temporal consistency, high accuracy, and fine spatial resolution. The CoRTAD is intended primarily for climate and ecosystem related applications and studies and was designed specifically to address questions concerning the relationship between coral disease and bleaching and temperature stress.
Use Limitations
  • accessLevel: Public
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Dataset Citation
  • Cite as: Casey, Kenneth; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2011). The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501). Version 1.1. National Oceanographic Data Center, NOAA. Dataset. [access date]
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Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
CoRIS Discovery Thesaurus
  • Numeric Data Sets > Oceanography
CoRIS Theme Thesaurus
  • EARTH SCIENCE > Biosphere > Aquatic Habitat > Coastal Habitat
  • EARTH SCIENCE > Biosphere > Aquatic Habitat > Reef Habitat
  • EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs
  • EARTH SCIENCE > Oceans > Ocean Temperature > Sea Surface Temperature
  • EARTH SCIENCE > Oceans > Ocean Temperature > Sea Surface Temperature > AVHRR
  • EARTH SCIENCE > Oceans > Ocean Temperature > Water Temperature
Global Change Master Directory (GCMD) Science Keywords
  • EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > COASTAL
  • EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > REEF > CORAL REEF
  • EARTH SCIENCE > Climate Indicators
  • EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE
  • EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE
  • EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Platform keywords NODC PLATFORM NAMES THESAURUS Global Change Master Directory (GCMD) Platform Keywords
  • NOAA-11 > National Oceanic & Atmospheric Administration-11
  • NOAA-14 > National Oceanic & Atmospheric Administration-14
  • NOAA-16 > National Oceanic & Atmospheric Administration-16
  • NOAA-17 > National Oceanic & Atmospheric Administration-17
  • NOAA-18 > National Oceanic & Atmospheric Administration-18
  • NOAA-7 > National Oceanic & Atmospheric Administration-7
  • NOAA-9 > National Oceanic & Atmospheric Administration-9
Instrument keywords NODC INSTRUMENT TYPES THESAURUS Global Change Master Directory (GCMD) Instrument Keywords
  • AVHRR-2 > Advanced Very High Resolution Radiometer-2
  • AVHRR-3 > Advanced Very High Resolution Radiometer-3
Place keywords NODC SEA AREA NAMES THESAURUS CoRIS Place Thesaurus
  • COUNTRY/TERRITORY > Marshall Islands > Marshall Islands > Marshall Islands (09N168E0000)
  • COUNTRY/TERRITORY > Micronesia > Micronesia (07N150E0000)
  • COUNTRY/TERRITORY > Northern Mariana Islands > Northern Mariana Islands > Northern Mariana Islands ( CNMI ) (18N146E0000)
  • COUNTRY/TERRITORY > Palau > Palau > Palau ( Belau ) (07N134E0000)
  • COUNTRY/TERRITORY > United States of America > American Samoa > American Samoa > American Samoa (14S170W0000)
  • COUNTRY/TERRITORY > United States of America > Florida
  • COUNTRY/TERRITORY > United States of America > Guam > Guam (13N144E0000)
  • COUNTRY/TERRITORY > United States of America > Hawaii > Hawaii > Hawaii (21N160W0000)
  • COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > Northwestern Hawaiian Islands (28N178W0000)
  • COUNTRY/TERRITORY > United States of America > Navassa Island > Navassa Island > Navassa Island (18N075W0001)
  • COUNTRY/TERRITORY > United States of America > Puerto Rico > Puerto Rico (18N066W0000)
  • COUNTRY/TERRITORY > United States of America > Texas > West Flower Garden Banks (27N093W0002)
  • COUNTRY/TERRITORY > United States of America > U. S. Virgin Islands > U. S. Virgin Islands > U. S. Virgin Islands (17N064W0000)
  • OCEAN BASIN > Atlantic Ocean
  • OCEAN BASIN > Atlantic Ocean > Caribbean Sea /North Atlantic Ocean > Puerto Rico > Puerto Rico (18N066W0000)
  • OCEAN BASIN > Atlantic Ocean > Caribbean Sea > Navassa Island > Navassa Island > Navassa Island (18N075W0001)
  • OCEAN BASIN > Atlantic Ocean > Caribbean Sea > Virgin Islands > Lesser Antilles > U. S. Virgin Islands (17N064W0000)
  • OCEAN BASIN > Atlantic Ocean > Gulf of Mexico > Florida
  • OCEAN BASIN > Atlantic Ocean > North Atlantic Ocean > Florida
  • OCEAN BASIN > Indian Ocean
  • OCEAN BASIN > Pacific Ocean
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Hawaiian Islands > Hawaii > Hawaii (21N160W0000)
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Marshall Islands > Marshall Islands (09N168E0000)
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands (28N178W0000)
  • OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Carolines > Micronesia (07N150E0000)
  • OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Carolines > Palau ( Belau ) (07N134E0000)
  • OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Guam > Guam (13N144E0000)
  • OCEAN BASIN > Pacific Ocean > Western Pacific Ocean > Mariana Archipelago > Northern Mariana Islands ( CNMI ) (18N146E0000)
Global Change Master Directory (GCMD) Location Keywords
  • GEOGRAPHIC REGION > GLOBAL OCEAN
Project keywords NODC PROJECT NAMES THESAURUS CRCP Project
  • 2068
  • 513
  • C047 The Coral Reef Temperature Anomaly Database
  • The Coral Reef Temperature Anomaly Database
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Casey, Kenneth; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2011). The Coral Reef Temperature Anomaly Database (CoRTAD) Version 2 - Global, 4 km Sea Surface Temperature and Related Thermal Stress Metrics for 1982-2008 (NODC Accession 0054501). Version 1.1. National Oceanographic Data Center, NOAA. Dataset. [access date]
Access Constraints
  • NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
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  • Digital data may be downloaded from NCEI at no charge in most cases. For custom orders of digital data or to obtain a copy of analog materials, please contact NCEI Information Services for information about current fees.
Lineage information for: dataset
Processing Steps
  • 2011-01-20T18:24:17 - NCEI Accession 0054501 v1.1 was published.
Output Datasets
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
  • AVHRR-2
  • AVHRR-3
Platform
  • NOAA-11
  • NOAA-14
  • NOAA-16
  • NOAA-17
  • NOAA-18
  • NOAA-7
  • NOAA-9
Last Modified: 2018-11-16T22:24:33
For questions about the information on this page, please email: NODC.DataOfficer@noaa.gov