Sea-surface temperature: Data to 2023

Study

Title

Sea-surface temperature: Data to 2023

en-NZ
Description
Data sources

NIWA used the Optimum Interpolation Sea Surface Temperature (OISST) version 2.1 product (Huang et al., 2021; Reynolds et al., 2002) to provide us with data to measure ocean and coastal sea-surface temperature. The OISST v2.1 product produced by the US agency NOAA (National Oceanic and Atmospheric Administration) is a long-term Climate Data Record that incorporates observations from different platforms (satellites, ships, buoys, and Argo floats) into a regular global grid. The dataset is interpolated to fill gaps on the grid and create a spatially complete map of sea surface temperature. Satellite and ship observations are referenced to buoys to compensate for platform differences and sensor biases. Through this series of overlapping and intercalibrated sensors, the AVHRR project has produced data since 1978 and continuous data since 1981. It provides daily sea-surface temperature estimates at a 1/4 of a degree spatial resolution. The OISST v2.1 data was processed to remove observation gaps caused by clouds and aggregated to a 9km resolution for the New Zealand region.

We used the OISST data to report findings in this indicator. The OISST data aligns with previous environmental reporting in New Zealand (Pinkerton et al., 2023). We aggregated sea-surface temperature values into hexagonal polygons, the majority of which have an area of approximately 288km2.

NIWA also used MODIS-Aqua (MODISA) measurements of long-wave (11 to 12µm) thermal radiation to estimate coastal sea-surface temperature at 1km spatial resolution (NASA, 2018). MODISA data are higher resolution than OISST data, but the time series is much shorter, providing complete data between 2003 and 2021 only. This data is described in Pinkerton et al. (2023).

Marine heatwave metrics were calculated from the OISST v2.1 data (Huang et al., 2021) between 1 January 1982 and 31 December 2022, with a fixed 30-year climatology (1 January 1983 to 31 December 2012) (Hobday et al., 2016). NIWA’s analysis used the ‘heatwaveR’ R package version 0.4.6 (Schlegel & Smit, 2018).

See Monitoring ocean health: 2023 update on satellite indicators for surface temperature, productivity and suspended solids for more information about the two satellite data sources.

References

Hobday, A. J., Alexander, L. V., Perkins, S. E., Smale, D., Straub, S. C., Oliver, E. C. J., Benthuysen, J. A., Burrows, M. T., Donat, M. G., Feng, M., Holbrook, N. J., Moore, P. J., Scannell, H. A., Gupta, A. S., & Wernberg, T. (2016). A hierarchical approach to defining marine heatwaves. Progress in Oceanography, 141, 227–238. https://doi.org/10.1016/j.pocean.2015.12.014

Huang, B., Liu, C., Banzon, V. F., Freeman, E., Graham, G., Hankins, B., Smith, T. S., & Zhang, H. (2021). Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1. Journal of Climate, 34(8), 2923–2939. https://doi.org/10.1175/jcli-d-20-0166.1

Pinkerton, M. H., Gall, M., Thoral, F., Sutton, P., & Wood, S. (2023). Monitoring ocean health: 2023 update on satellite indicators for surface temperature, productivity and suspended solids. Prepared for the Ministry for the Environment. NIWA Client Report No: 2023217WN_rev1. https://environment.govt.nz/publications/monitoring-ocean-health-2023-update-on-satellite-indicators-for-surface-temperature-productivity-and-suspended-solids

Reynolds, R. W., Rayner, N. A., Smith, T. M., Stokes, D. C., & Wang, W. (2002). An improved in situ and satellite SST analysis for climate. Journal of Climate, 15(13), 1609–1625. https://doi.org/10.1175/1520-0442(2002)015<1609:AIISAS>2.0.CO;2

Schlegel, R. W., & Smit, A. J. (2018). heatwaveR: A central algorithm for the detection of heatwaves and cold-spells. Journal of Open Source Software, 3(27), 821. https://doi.org/10.21105/joss.00821 en-NZ
Date

Coverage

Keywords
Sea-surface temperature, Sea, Ocean, Temperature, Warming
Date
2023

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6 9/07/2024 10:46:40 AM