Marquette
Craig D.
Marquette
Craig D.
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Technical ReportAcoustics and oceanographic observations collected during the QPE Experiment by Research Vessels OR1, OR2 and OR3 in the East China Sea in the Summer of 2009(Woods Hole Oceanographic Institution, 2010-08) Newhall, Arthur E. ; Lynch, James F. ; Gawarkiewicz, Glen G. ; Duda, Timothy F. ; McPhee, Neil M. ; Bahr, Frank B. ; Marquette, Craig D. ; Lin, Ying-Tsong ; Jan, Sen ; Wang, Joe ; Chen, Chi-Fang ; Chiu, Linus Y. S. ; Yang, Yiing-Jang ; Wei, Ruey-Chang ; Emerson, Chris ; Morton, David ; Abbot, Ted ; Abbot, Philip A. ; Calder, Brian ; Mayer, Larry A. ; Lermusiaux, Pierre F. J.This document describes data, sensors, and other useful information pertaining to the ONR sponsored QPE field program to quantify, predict and exploit uncertainty in observations and prediction of sound propagation. This experiment was a joint operation between Taiwanese and U.S. researchers to measure and assess uncertainty of predictions of acoustic transmission loss and ambient noise, and to observe the physical oceanography and geology that are necessary to improve their predictability. This work was performed over the continental shelf and slope northeast of Taiwan at two sites: one that was a relatively flat, homogeneous shelf region and a more complex geological site just shoreward of the shelfbreak that was influenced by the proximity of the Kuroshio Current. Environmental moorings and ADCP moorings were deployed and a shipboard SeaSoar vehicle was used to measure environmental spatial structure. In addition, multiple bottom moored receivers and a horizontal hydrophone array were deployed to sample transmission loss from a mobile source and ambient noise. The acoustic sensors, environmental sensors, shipboard resources, and experiment design, and their data, are presented and described in this technical report.
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ArticleShelfbreak frontal structure and processes north of Cape Hatteras in winter(Sears Foundation for Marine Research, 2008-11) Gawarkiewicz, Glen G. ; Churchill, James H. ; Bahr, Frank B. ; Linder, Christopher A. ; Marquette, Craig D.The circulation north of Cape Hatteras is complicated by the proximity of the shelfbreak front, the Gulf Stream, and convergent shelf flow from the Middle and South Atlantic Bights. A three-week cruise in this region in January/February, 2005 was undertaken in order to study the structure of the shelfbreak front as it terminates near Cape Hatteras and to quantify the freshwater transport from the Middle Atlantic Bight shelf into the Gulf Stream. Two strongly contrasting conditions were identified. Early in the cruise, the Gulf Stream directly abutted the shelfbreak at Cape Hatteras and drove a northward flow over the continental shelf as far north as 35°45′N. All of the Middle Atlantic Bight shelf water terminated by 35°30′N. Ten days later, the Gulf Stream had moved away from the shelfbreak south of Cape Hatteras and strong winds from the north were present. During this time, the shelfbreak frontal jet was strong (maximum southward velocity of approximately 0.5 m s-1 with a Rossby number of 2) and abruptly turned eastward and offshore between 35°35′N and 35°45′N. Freshwater transport eastward from the shelfbreak jet was 7.4 mSv and southward over the shelf was 19.9 mSv, giving a total freshwater transport of 27.3 mSv. This likely represents an upper bound due to the strong wind forcing. Implications of these results for the freshwater budget of the Middle Atlantic Bight shelf, stability properties of the shelfbreak front in this region, and the formation of “Ford water” in the Gulf Stream are discussed.