Assessing the Long-Term SST Response of the Red Sea to Natural Climate
Variability
Abstract
Recent observations of warming trends in the Red Sea raise more
attention to the response of the basin under a warming climate. Using
two remotely sensed datasets, the Hadley Centre Sea Ice and Sea Surface
Temperature [HadISST] and Extended Reconstructed Sea Surface
Temperature [ERSST.v3], we investigate the reported sudden increase
in the Red Sea sea surface temperatures (SST) in terms of average and
maximum and assess their relation to multi-decadal climate variability.
Prior to the analysis, the two datasets are successfully validated with
respect to their ability to reproduce the recent observed and reported
trends and their spatial features. Analysis of long-term SST variability
revealed a sequence of alternating and similar in amplitude positive and
negative trends, characterized by a period of nearly 70 years. Similar
oscillations have been reported in other basins and have been related to
atmospheric disturbances associated with the Atlantic Multidecadal
Oscillation (AMO). A point-by-point spectral analysis of SST evolution
shows a significant correlation with the basic modes of the AMO that
explains a large fraction of its temporal and spatial variability.
Projections on the major modes of the spectral analysis suggest a
possible decreasing effect on local SST in the near future. Under this
assumption, recent projected trends in the Red Sea may be exaggerated,
whilst trends that may be related to anthropogenic influence could be
masked by the projected negative influence of the AMO in the near
future.