WINTER TRANSPORT AND SEA-LEVEL FLUCTUATIONS IN HECATE STRAIT, BRITISH-COLUMBIA

Observed winter transport and adjusted sea level fluctuations in Hecat e Strait were investigated using empirical orthogonal function and coh erence analyses. The responses to large-scale and local wind forcings were identified by the distinctive spatial patterns of their adjusted sea level responses. At the resolved periods of 2 to 48 days, the larg e-scale and the local wind forcings were of roughly equal importance i n driving transport fluctuations. Comparison of observations with a co nceptual model indicates that the adjusted sea level in the northeast corner of the strait gives a good measure of response to both the loca l and large-scale wind forcings. This provides a physical explanation for the observed high correlation between the adjusted sea, level at P rince Rupert and the winter transport fluctuations in Hecate Strait. W e also show that the transport fluctuations are associated with a part icular spatial pattern of the velocity field, which represents roughly 1/4 of the energy in the observed winter velocity fluctuations measur ed at an array of current meters. This has implications for the use of surrogate transport series to hindcast oceanographic conditions in He cate Strait.