Deep Water Renewal in Subarctic Fjord

As part of a comprehensive program of marine environmental studies in Port Valdez, Alaska, currents were measured in or near Valdez Narrows almost continuously for more than two years. The purpose of these measurements was to investigate the exchange of water between Port Valdez and Prince William Sound. Intensive profiling of temperature and salinity in Port Valdez and adjacent waters has enabled observation of water exchange processes that are effective on a seasonal basis. However, the current meter data have shown that these processes are occasionally overshadowed by short-term events that are of comparable effectiveness in promoting the exchange of water between Port Valdez and Prince William Sound. The latter events have typical durations of two to five days and their timing is apparently related to the passage of weather systems through the Gulf of Alaska. The random nature of these events, in conjunction with the generally predictable seasonal exchange processes, suggests that the notion of a unique residence time for Port Valdez and similar fjords is inappropriate.