Sea surface temperature variability at the Scripps Institution of Oceanography Pier
Abstract
Sea surface temperature (SST) has been measured from near the end of the SIO pier daily since 1916. It is one of the world’s longest instrumental time series of SST. It is widely used in studies of climate and marine ecosystems and in fisheries management. We hypothesized that a discontinuity exists in 1988, when the old pier was replaced with the present pier. A regression of annual mean SST at SIO (SSTSIO) on the Pacific Decadal Oscillation index for 1916-1987 was used to predict annual mean SST (SSTSIO, PDO) for 1916-present. The residual (ResSSTSIO = SSTSIO - SSTSIO,PDO) time series shows a positive discontinuity in 1988, when the present SIO pier was first used to measure SSTSIO. No discontinuity in 1988 was observed for ResSST at 12 other shore stations or nearby waters. Use of the first principal component of other shore station time series of annual mean SST as the predictor yields similar results. SSTSIO measured over three days shows a diel cycle and short-term variability consistent with rip current transport of warm surf zone water to the end of the SIO pier. We hypothesize that rip current transport increased with the change from the old to the present pier and contributed to the observed discontinuity in SIO pier SST. We estimate an artifact of ~ +0.45°C due to both rapid (1988 pier change) and gradual processes. Adjusting the SIO pier SST time series for this artifact reduces the long-term trend from +1.1°C/century to +0.6°C/century, consistent with the global rate of change of SST over the past century
Info
Journal Article, 2014
UN SDG Classification
DK Main Research Area
Science/Technology
