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The color of sea level: importance of spatial variations in spectral shape for assessing the significance of trends

Hughes, C. W.; Williams, S. D. P.. 2010 The color of sea level: importance of spatial variations in spectral shape for assessing the significance of trends. Journal of Geophysical Research, 115, C10048. 18, pp. 10.1029/2010JC006102

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Abstract/Summary

We investigate spatial variations in the shape of the spectrum of sea level variability, based on a homogeneously-sampled 12-year gridded altimeter dataset. We present a method of plotting spectral information as color, focusing on periods between 2 and 24 weeks, which shows that significant spatial variations in the spectral shape exist, and contain useful dynamical information. Using the Bayesian Information Criterion, we determine that, typically, a 5th order autoregressive model is needed to capture the structure in the spectrum. Using this model, we show that statistical errors in fitted local trends range between less than 1 and more than 5 times what would be calculated assuming “white” noise, and the time needed to detect a 1 mm/yr trend ranges between about 5 years and many decades. For global-mean sea level, the statistical error reduces to 0.1 mm/yr over 12 years, with only 2 years needed to detect a 1 mm/yr trend. We find significant regional differences in trend from the global mean. The patterns of these regional differences are indicative of a sea level trend dominated by dynamical ocean processes, over this period

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2010JC006102
Programmes: POL Programmes > Sea-level, bottom pressure and space geodesy
Oceans 2025 > Climate, ocean circulation and sea level
Oceans 2025
POL Programmes > Sea-level, bottom pressure and space geodesy > Changes in global and regional sea/land levels
ISSN: 0148-0227
Additional Keywords: SEA LEVEL; SPECTRUM
NORA Subject Terms: Marine Sciences
Date made live: 25 Oct 2010 13:03
URI: http://nora.nerc.ac.uk/id/eprint/10399

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