Atmospheric Forcing Of Wave States In The Southeast Chukchi Sea Item Type Thesis Authors Francis, Oceana P. Download date 28/09/2021 07:50:30 Link to Item http://hdl.handle.net/11122/9124 ATMOSPHERIC FORCING OF WAVE STATES IN THE SOUTHEAST CHUKCHI SEA By Oceana Puananilei Francis RECOMMENDED: Advisory Committee Chair CCcoQ Chair, Department of Atmospheric Sciences APPROVED: Dean, College of Natural Schjrfce and Mathematics Dean of the Graduate School Date ATMOSPHERIC FORCING OF WAVE STATES IN THE SOUTHEAST CHUKCHI SEA A DISSERTATION Presented to the Faculty of the University of Alaska Fairbanks In Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY By Oceana P. Francis, P.E., M.Sc. Fairbanks, Alaska May 2012 ©2012 Oceana Puananilei Francis UMI Number: 3528864 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3528864 Published by ProQuest LLC 2012. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Abstract The objective of this study was to assess the impact that the ocean state, particularly ocean waves, have on coastal communities and operations in the Western Alaska region. In situ measurements and one-dimensional spectra models, were used to link observed wave activity - wind-sea and swells - to their synoptic drivers. Bottom- mounted Recording Doppler Current Profilers (RDCPs) were placed at offshore and nearshore locations in the southeast Chukchi Sea, Alaska, during 2007 and 2009-2010. The highest significant wave height (SWH) “events” were defined as wave heights above 2m and 3m for a duration of 6h or more. Results show that SWH events appeared to be driven by three types of systems, 1) cyclonic systems that moved into the eastern Bering Sea and then stalled there, 2) cyclonic systems that moved into the eastern Chukchi Sea and then loitered there, and 3) a cyclonic system over the Brooks Range, a less common occurrence. Results also show the offshore region having highest SWHs with an east wind and wave direction, and classified as a wind-sea state. For the nearshore region, highest SWHs with south and west wind and wave directions, generally showed a swell state. Agreement between one-dimensional spectral models and in situ measurements was greatest for the higher wind-sea state in the offshore region, while discrepancies arose for the lower swell state in the nearshore region. Cross-validation of in situ measurements with satellite altimeter radar measurements were also conducted. Good correlation was found for the offshore regions iv but not for the nearshore regions. Satellite observations were also used to assess wave conditions in the Arctic during the years 1993-2011. A 0.020m/year increase of SWH for the SE Chukchi Sea and a 0.025m/year increase for the Pacific-Arctic, was found which correlates well with diminishing sea ice and the heighted wind speed, also shown in this study. V Dedication This dissertation is dedicated to one of the earliest ocean navigators in the World, Polynesians, who used only the stars, ocean currents and swells to guide them across the Pacific Ocean. Table of Contents Page Signature Page ........................................................................................................................... i Title Page...................................................................................................................................ii Abstract .................................................................................................................................... iii Dedication ..................................................................................................................................v Table of Contents .....................................................................................................................vi List of Figures .......................................................................................................................... xi List of Tables .........................................................................................................................xiv List of Appendices ..................................................................................................................xv Acknowledgements .............................................................................................................. xvii Chapter 1 Introduction .............................................................................................................. 1 1.1. Project motivation ...................................................................................................... 8 1.2. Project Goals .............................................................................................................12 References ............................................................................................................................16 Chapter 2 Synoptic forcing of wave states in the southeast Chukchi Sea, Alaska, at an offshore location ..................................................................................................................... 20 Abstract ................................................................................................................................20 2.1. Introduction ...............................................................................................................22 2.2. Background ...............................................................................................................26 2.2.1. Atmospheric circulation and synoptic conditions ......................................... 26 2.2.2. Site selection and RDCP instrument deployment ..........................................28 2.3. Methods and data .....................................................................................................29 2.3.1. Atmospheric datasets ....................................................................................... 30 2.3.2. RDCP wave parameters ...................................................................................31 2.3.3. Wave event and atmospheric analysis ............................................................33 2.4. Station 2007 Results .................................................................................................34 2.4.1. Station 2007 overview ..................................................................................... 34 2.4.2. SE1 (SWH-3m-3), September 18-21,2007 UTC ..........................................36 2.4.3. SE2 (SWH-3m-15), November 22 - December 2, 2007 UTC ......................41 2.5. Conclusion.................................................................................................................46 Acknowledgements .............................................................................................................49 References ........................................................................................................................... 50 Chapter 3 Synoptic forcing of wave states in the southeast Chukchi Sea, Alaska, at nearshore locations ..................................................................................................................66 Abstract................................................................................................................................66 3.1. Introduction ...............................................................................................................68 3.2. Methods and data ..................................................................................................... 71 3.2.1. Atmospheric datasets ....................................................................................... 72 3.2.2. RDCP instrument deployment and wave parameters ....................................73 3.2.3. Wave event and atmospheric analysis ............................................................75 3.3. Station 2009N and 2009S Analysis and Results ....................................................76 3.3.1. Station 2009N and 2009S overview .............................................................. 76 3.3.2. SE3 (2009N-2m-12), July 22-23,2010 UTC ................................................. 81 3.3.3. SE4 (2009S-2m-15), July 16-18,2010 UTC ................................................. 85 3.3.4. SE5 (2009S-2m-20), August 17-20, 2010 UTC ............................................ 88 3.3.5. Comparison of Station 2009N and 2009S for SE3, SE4, and SE5 91 3.4. Discussion and Conclusion .....................................................................................93 Acknowledgements ............................................................................................................ 97 References ........................................................................................................................... 98 Chapter 4 A description of one-dimensional wave spectra in the southeast Chukchi Sea location ...................................................................................................................................119