In situ and remotely sensed temperature comparisons on a Central Pacific atoll
Climate-induced warming events increasingly threaten coral reefs, heightening the need for accurate quantification of baseline temperatures and thermal stress in these ecosystems. To assess the strengths and weaknesses of NOAA satellite sea surface temperature and in situ measurements, we compared 5 yr of these data on Kiritimati atoll, in the central equatorial Pacific. We find that (1) satellite measurements were similar to in situ measurements (~ 10 m depth), albeit slightly warmer, with measurements converging once above Kiritimati’s maximum monthly mean; (2) in situ loggers detected subsurface cooling events missed by satellites; (3) thermal baselines and anomalies were consistent around the island; and (4) in situ degree heating week (DHW) calculations were most comparable to NOAA DHWs when calculated using NOAA’s climatology. These results suggest that NOAA’s satellite products accurately reflect conditions on central Pacific reefs, but that in situ measurements can identify localized events, such as subsurface upwelling, that may be ecologically relevant for corals.
KeywordsNOAA CoralTemp Kiritimati Kiribati Sea surface temperature (SST) Degree heating weeks Thermal anomalies
Thanks to the Kiritimati Field Team, especially K. Tietjen, for assistance in deploying and retrieving loggers, and to the NOAA CRW team for developing the satellite products used in these analyses. Thanks to J Schanze for discussion on an earlier version of the manuscript. DCC acknowledges funding from an NSERC Vanier Canada Graduate Scholarship, AAUS, a National Geographic Young Explorers Grant, the University of Victoria (UVic), the Women Divers Hall of Fame, and Divers Alert Network. This comparison was made possible by a Sea-Bird Electronics equipment grant to DCC. DCC and JKB acknowledge funding from UVic and UVic’s Centre for Asia–Pacific Initiatives. JKB acknowledges support from the Schmidt Ocean Institute, the David and Lucile Packard Foundation, the Rufford Maurice Laing Foundation, an NSERC Discovery Grant and E.W.R. Steacie Fellowship, the Canadian Foundation for Innovation, and a Pew Fellowship in Marine Conservation. KMC acknowledges support from NSF award 1446343.
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Conflict of interest
On behalf of all authors, the corresponding author states that there is no conflict of interest.
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