Spatio-temporal variability of ocean temperature in the Portugal Current System
Article first published online: 22 APR 2006
Copyright 2006 by the American Geophysical Union.
Journal of Geophysical Research: Oceans (1978–2012)
Volume 111, Issue C4, April 2006
How to Cite
2006), Spatio-temporal variability of ocean temperature in the Portugal Current System, J. Geophys. Res., 111, C04010, doi:10.1029/2005JC003051., and (
- Issue published online: 22 APR 2006
- Article first published online: 22 APR 2006
- Manuscript Accepted: 25 JAN 2006
- Manuscript Revised: 28 OCT 2005
- Manuscript Received: 10 MAY 2005
 A dynamic process convolution model (DPCM) is used to investigate the evolution and spatial distribution of monthly ocean temperature anomalies in the Portugal Current System. The analysis is performed with 20th century standard depth measurements from the National Oceanographic Data Center, ranging from the surface to 500 m depth. The proposed DPCM decomposes the temporal variability into short-term non-linear components and long-term linear trends, with both components varying smoothly across latitude, longitude and depth. An important feature of the DPCM is that it allows the assessment of trend significance without ad hoc corrections, since the residuals are spatially and temporally uncorrelated. In the analyzed period, an overall warming of coastal surface waters off the west Iberian Peninsula is found, together with fading cross-shelf temperature gradients and increased coastal stratification. Since previous studies also found that upwelling-favorable winds have weakened from the 1940s onward, these results most likely reflect a long-term weakening of the coastal upwelling regime. Transient periods of temperature change are also described and associated with known variability in the North Atlantic, and a final discussion on the link between the observed trends and anthropogenic forcing on climate is presented.