Evolution of the Thermal History Product Suite


Climate change threatens even the best-protected and most-remote coral reef ecosystems. Management in the face of climate change must incorporate how various factors (e.g., benthic structure, currents and local upwelling, connectivity, herbivore abundance, thermal history) affect coral and reef ecosystem resilience. Research over the last decade indicates that thermal history is among the most important factors influencing coral reef resilience.

With support from the NOAA Coral Reef Conservation Program, NOAA Coral Reef Watch (CRW) developed a variety of Thermal History metrics for coral reef management. In the current Version 3.2 (released January 2022), several Sea Surface Temperature (SST) metrics are calculated for coral reef-containing locations and adjacent waters and are arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

Below is a list of the prior versions of the Thermal History product suite, and a brief description of each (including improvements CRW made to each version, or metrics within that product version).




Version 1.0 Product Suite
(released July 2014)

For the Version 1.0 Thermal History product suite, NOAA CRW developed multiple metrics for coral reef-containing locations and adjacent waters that were arranged into three themes: Historical Variability, Stress Frequency, and Onset Timing.

These metrics were derived from Pathfinder v5.2 ~4km (1/24°) daily SST data for the period 1985-2012, provided by the Group for High Resolution Sea Surface Temperature (GHRSST) and the U.S. National Oceanographic Data Center (NODC). The Pathfinder project was supported in part by a grant from the NOAA Climate Data Record (CDR) Program for satellites.

 



Version 1.1 Product Suite
(released September 15, 2017)

For the Version 1.1 Thermal History product suite, NOAA CRW enhanced its SST metrics for coral reef-containing locations and adjacent waters to include six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

As with the Version 1.0 product suite, the Version 1.1 Thermal History metrics were derived from the Pathfinder v5.2 ~4km (1/24°) daily SST dataset, for the period 1985-2012, provided by GHRSST and NOAA's National Centers for Environmental Information (NCEI, formerly NODC).

 



Version 2.0 Product Suite
(released September 24, 2018)

For the Version 2.0 Thermal History product suite, NOAA CRW maintained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

However, as an improvement, CRW derived the Version 2.0 Thermal History metrics from its Version 1.0 daily global 5km (1/20°) CoralTemp SST data product, for the period 1985-2017. Source data for CoralTemp were from the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) operational near real-time daily global 5km Geostationary-Polar-orbiting (Geo-Polar) Blended Night-only SST Analysis; the NOAA/NESDIS 2002-2016 reprocessed daily global 5km Geo-Polar Blended Night-only SST Analysis; and the United Kingdom Met Office 1985-2002 daily global 5km night-only SST reanalysis produced on the Operational SST and Sea Ice Analysis (OSTIA) system.

 



Version 2.1 Product Suite
(released September 13, 2019)

For the Version 2.1 Thermal History product suite, NOAA CRW retained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

As an enhancement, however, CRW derived the Version 2.1 Thermal History metrics from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2018. Source data for CoralTemp continued to be from the NOAA/NESDIS operational near real-time daily global 5km Geo-Polar Blended Night-only SST Analysis; the NOAA/NESDIS 2002-2016 reprocessed daily global 5km Geo-Polar Blended Night-only SST Analysis; and the United Kingdom Met Office 1985-2002 daily global 5km night-only SST reanalysis produced on the OSTIA system.

 



Version 3.1.0 Product Suite
(released October 9, 2020)

For the Version 3.1.0 Thermal History product suite, NOAA CRW maintained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

However, CRW improved the Version 3.1.0 Thermal History metrics by including an additional year's worth of data, from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2019. Source data for CoralTemp continued to be from the NOAA/NESDIS operational near real-time daily global 5km Geo-Polar Blended Night-only SST Analysis (from 2016-present); the NOAA/NESDIS 2002-2016 reprocessed daily global 5km Geo-Polar Blended Night-only SST Analysis; and the United Kingdom Met Office 1985-2002 daily global 5km night-only SST reanalysis produced on the OSTIA system.

 



Version 3.1.1 Product Suite
(released January 26, 2021)

For the Version 3.1.1 Thermal History product suite, NOAA CRW retained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

However, CRW enhanced the Version 3.1.1 Thermal History metrics by including an additional year's worth of data, from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2020. Source data for CoralTemp continued to be from the NOAA/NESDIS operational near real-time Daily Global 5km Geo-Polar Blended Night-only SST Analysis, from October 2016 to present; the NOAA/NESDIS Daily Global 5km Geo-Polar Blended Night-only SST Reanalysis (a reprocessed dataset), from November 2002 to October 2016; and the Daily Global 5km Night-only SST Reanalysis produced by the United Kingdom Met Office, on the OSTIA system, from January 1985 to November 2002.

 



Version 3.1.2 Product Suite
(released September 15, 2021)

For the Version 3.1.2 Thermal History product suite, NOAA CRW maintained the prior SST metrics that were arranged into six themes (Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History), and it retained the same source data; i.e., the Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2020.

However, CRW improved the Version 3.1.2 product suite by addressing a bug in the 'reef_mask' variable present in the following netCDF data files:

  • noaa_crw_thermal_history_annual_history_v3.1.1.nc
  • noaa_crw_thermal_history_climatology_v3.1.1.nc
  • noaa_crw_thermal_history_sst_trend_v3.1.1.nc
  • noaa_crw_thermal_history_sst_variability_v3.1.1.nc
  • noaa_crw_thermal_history_stress_freq_v3.1.1.nc
  • noaa_crw_thermal_history_stress_onset_v3.1.1.nc

In the prior Version 3.1.1 Thermal History metric data files, the variable 'reef_mask' was latitudinally offset to the south relative to all other variables within the files. This was amended in the Version 3.1.2 Thermal History netCDF data files.

 



Version 3.2 Product Suite
(released January 25, 2022)

For the Version 3.2 Thermal History product suite, NOAA CRW retained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

CRW enhanced the Version 3.2 Thermal History metrics by including an additional year's worth of data, from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2021. Source data for CoralTemp are from the NOAA/NESDIS operational near real-time Daily Global 5km Geo-Polar Blended Night-only SST Analysis, from October 2016 to present; the NOAA/NESDIS Daily Global 5km Geo-Polar Blended Night-only SST Reanalysis (a reprocessed dataset), from November 2002 to October 2016; and the Daily Global 5km Night-only SST Reanalysis produced by the United Kingdom Met Office, on the OSTIA system, from January 1985 to November 2002.

 



Version 3.3 Product Suite
(released February 27, 2023)

For the Version 3.3 Thermal History product suite, NOAA CRW retained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

CRW enhanced the Version 3.3 Thermal History metrics by including an additional year's worth of data, from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2022. Source data for CoralTemp are from the NOAA/NESDIS operational near real-time Daily Global 5km Geo-Polar Blended Night-only SST Analysis, from October 2016 to present; the NOAA/NESDIS Daily Global 5km Geo-Polar Blended Night-only SST Reanalysis (a reprocessed dataset), from November 2002 to October 2016; and the Daily Global 5km Night-only SST Reanalysis produced by the United Kingdom Met Office, on the OSTIA system, from January 1985 to November 2002.

 



Version 3.4 Product Suite
(released November 30, 2023)

For the Version 3.4 Thermal History product suite, NOAA CRW modified the calculation of select metrics, as discussed in more detail below. These all remain categorized within the same six themes as in Version 3.3: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

  • We identified and resolved an issue with the climatology. During previous product updates, when additional years of data were added, the climatology did not remain static; this had downstream consequences for other metrics that were calculated using the climatology. The climatology is now validated and is static. Future additions of yearly data should not affect the climatology.
  • Within the Stress Onset theme, the metric, “Mean Onset – Significant Bleaching-level Heat Stress”, was changed to “Mode Onset – Significant Bleaching-level Heat Stress”. The use of a mean average in this metric was problematic for coral reefs, where stress onset occurred in both the early calendar months and late calendar months (e.g., January and also December). Mode average, which speaks to the most frequently occurring month of onset, year-round, in the dataset, is now utilized to alleviate this issue.
  • Within the Stress Onset theme, we changed the calculation for the metric, “Onset Variability – Significant Bleaching-level Heat Stress”. Previously, this metric was calculated using a start date of January 1st of each year. The v3.4 product calculates onset variability relative to the Maximum Monthly Mean (MMM) month for each individual data pixel. The start date used to calculate variability for each pixel is now the first day of the calendar month that is four months prior to the MMM month.
  • Within the SST Trend theme, we identified and resolved an error in the calculation of decadal trends. This resolved multiple downstream errors that had existed in different SST Trend and SST Variability metrics.

 



Version 3.5 Product Suite
(released January 31, 2024)

For the Version 3.5 Thermal History product suite, NOAA CRW retained the prior SST metrics that were arranged into six themes: Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History.

CRW enhanced the Version 3.5 Thermal History metrics by including an additional year's worth of data, from its Version 3.1 daily global 5km (1/20°) CoralTemp satellite SST data product, for the period 1985-2023. Source data for CoralTemp are from the NOAA/NESDIS operational near real-time Daily Global 5km Geo-Polar Blended Night-only SST Analysis, from October 2016 to present; the NOAA/NESDIS Daily Global 5km Geo-Polar Blended Night-only SST Reanalysis (a reprocessed dataset), from November 2002 to October 2016; and the Daily Global 5km Night-only SST Reanalysis produced by the United Kingdom Met Office, on the OSTIA system, from January 1985 to November 2002.