Related Research Areas
Carbon Cycle & Ecosystems

The NOAA Coral Reef Watch (CRW) Decision Support System (DSS) has historically used operational, near-real-time, global satellite sea surface temperature (SST) products at 50-km resolution for monitoring and predicting mass coral reef bleaching. A new DSS for ecosystem-based management of tropical coral reef environments is being developed that includes thermal products at 5-km resolution. These products use NOAA’s daily updated 5km-resolution SST product and a new climatology based on version 5.2 Pathfinder daily nighttime-only SST data set (PF52).

The thermal products in support of DSS are anomaly based products. It is the SST anomaly, rather than SST itself that is key to the success of the products. Therefore creating a high quality climatology which is used as a reference for calculating the anomaly is essential to the products as wrongly developed climatology will lead to wrongly calculated anomalies, one of the thermal products, and wrongly calculated anomalies will in turn lead to other wrongly calculated products such as HotSpots, Degree Heating Weeks (DHW) and Alert Areas.

PF52 provides consistent long term global SST records from January 1985 to December 2010. The broad spatial coverage and long term records are very useful for the development of a stable and high quality climatology. The data set however, is a very gappy data set. In the tropical region within 35 degree in latitude, a region where most of the world coral reefs locate and where we care the most, only 12.58% of the data have quality level 4 and above, the data that we consider having research quality, and the rest 87.42% are considered missing. Therefore some gap filling needs to be done to this data set in order to create a high quality climatology using it.

We use a combined temporal and spatial gap filling algorithm to fill the gaps in the data. This is a two-step process. The temporal gap filling fills the gaps in the temporal domain using a maximum 30-day window. Any gaps equal or shorter than 30 days are filled by linear interpolation, while longer than 30 days are left unfilled. The spatial gap filling fills the gaps in the spatial domain using a maximum 52 x 52 km (13 x 13 PF52 pixel) spatial window. When the gaps are being filled, we always make sure to use the nearest values both temporally and spatially. After the combined gap filling we have 95.21% values to use in the tropical region. The gap filled SSTs are then used for the creation of the climatology. Because of the huge data volume and heavy computations involved in this process, the work is run on NEX, which proves to be powerful, reliable and convenient to use.

The new high-resolution 5km suite will significantly advances NOAA CRW’s capability for near-real-time satellite coral bleaching thermal stress monitoring. With higher spatial and temporal resolution products, CRW can provide service at or close to reef-scale. After further testing and evaluation of the 5km product suite, CRW’s decade-old operational 50km product suite, which has provided pioneer service to global coral reef communities, will be retired.

Project Leads:

Muller-Karger, F. ., University of South Florida, St. Petersburg, USA,

Eakin, C. M., Coral Reef Watch, NOAA, College Park, MD, USA,

Guild, L. S., NASA Ames Research Center, NASA, Moffett, USA,


Li, J. ., Coral Reef Watch, NOAA, College Park, MD, USA,

Vega_Rodriguez, M. ., University of South Florida, St. Petersburg, USA,

Liu, G. ., Coral Reef Watch, NOAA, College Park, MD, USA,

Heron, S. F., Coral Reef Watch, NOAA, College Park, MD, USA,

Nemani, R., NASA Ames Research Center, NASA, Moffett, USA,

Wood, L., UNEP - WCMC, Cambridge, United Kingdom,

Lynds, S., CIRES, University of Colorado, Boulder, USA,


Andy Michaelis from NASA Ames Research Center provides a lot of help on the coding on NEX, and Jennifer Dungan also from NASA Ames Research Center provides much general information on NEX. Hiro helped a lot for the first year for the four-year project. We really appreciate their efforts and contributions.


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Started: Oct 18, 2012

Last Activity: Nov 01, 2012



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