Moores_Wu_POM_ FINAL Report JUL-SEP 06

Quarterly Progress Report Form - Oil Spill Recovery Institute This report may be submitted by mail, fax or e-mail P.O Box 705 - Cordova, AK 99574 - Fax: (907) 424-5820 - E-mail: frontdes@pwssc.gen.ak.us Deadline for this report: All grants over $25,000 shall submit this report within 30 days of the end of the quarter Today’s date: 10/31/2006 Name of awardee/grantee: University of Miami, Rosenstiel School of Marine and Atmospheric Science, PI: Professor Christopher N.K Mooers OSRI Contract Number: 06-10-01 Project title: How Does a Semi-Enclosed Sea Respond to External and Internal Forcings? This report covers _ Oct.-Dec Jan.-March _ April-June X July-Sept 1st quarter 2nd quarter 3rd quarter 4th quarter PART I - Progress Report on Activities In a short paragraph (3-10 sentences), please describe project activities since your last report 2006 Annual Report on Activities: Xinglong Wu 31 October 2006 ABSTRACT:    EPWS/NFS1  and  PWS/NFS2  provide  daily  operational  updates through the Internet, along with available observations for PWS from NOS 3  tide gauges,   NDBC4  buoys   and   C­MAN5  stations   RAMS6  and   Global­NCOM7 continue to be effective in providing surface forcings and OBCs 8, respectively, for EPWS­POM9,   which   is   the   modeling   backbone   of  EPWS/NFS   As   the   second stage   for   comprehensive   assessments   of   EPWS/NFS   versus   PWS/NFS   versus observations, vertical velocity profiles at HE and MS, as well as at NDBC buoy 46060,   are   investigated   Coastal   sea   levels,   surface   temperature   at   NDBC   and NOS  stations,   and  the   seasonal  cycle   of  monthly­mean  temperature   profiles   at GAK110 are also examined. These studies document the superiority of EPWS/NFS over   its   predecessor   EPWS/NFS   products   are   then   applied   to   explore   the coherence and phase between total transports through HE and MS, emulation of monthly­mean transport through HE, seasonal mesoscale variability in the Central Sound, and the spatial structure of the monthly mean flow and mass fields at HE for one year 1: Prince William Sound/Nowcast­Forecast System 2: Extended Prince William Sound/Nowcast­Forecast System 3: National Ocean Service 4: National Data Buoy Center 5: Coastal­Marine Automated Network 6: Regional Atmospheric Modeling System 7: Global ­ Navy Coastal Ocean Model 8: Open Boundary Conditions 9: Princeton Ocean Model 10: A hydrographic station located at the mouth of Resurrection Bay near Seward, Alaska and sampled by UAF STATUS OF OBJECTIVES:  At the end of my second OSRI Fellowship year performing   the   proposed   research,   the   status   of   my   objectives   is   summarized below, 1)   Numerical   models:   alternative   versions   of   PWS­POM   and   EPWS­POM implemented with a curvilinear grid, increased horizontal resolution, and a smaller domain   (but   with   the   Alaska   Shelf   included   for   EPWS­POM)   for   conducting process studies; Completed 2) Assistance in assessing Global­NCOM as a source of open boundary conditions for EPWS­POM; Completed 3) Assistance in assessing RAMS as a source of surface forcing for EPWS­POM; Completed 3) Assistance in the real­time operation of  PWS/NFS; Completed 4) Assistance in the real­time operation of  EPWS/NFS; Completed 5) Assessments of PWS/NFS versus EPWS/NFS versus observations:         i) Comparison of velocity profiles at HE and MS, as well as NDBC buoy 46060; Completed          ii) Comparison of coastal sea levels at tide gauges, surface temperatures at NDBC and NOS stations, as well as monthly­mean temperature profile at GAK1; Completed       iii) Detection of Helmholtz Resonance of Prince William Sound; Completed    iv) Analysis of the coherence and phase between total transports through HE and MS; Completed      v) Emulation of monthly­mean transport through HE; Completed      vi) Description of  simulated seasonal mesoscale variability in Central Sound;  Completed  ROADBLOCKS   ENCOUNTERED:  The   new   dataset   of   two­point   high­ resolution   ADCP   measurements   at   both   HE   and   MS   in   2005 (http://ak.aoos.org/op/historic_moor.php   ?region=PWS)   provides,   for   the   first time,  deep insight into the cross­sectional velocity structures, which are known to be crucial to understanding and calculating the circulation in the Central Sound However, no performance information for these measurements has been provided, and the quality control of the data is unknown The ADCP measurements at NDBC buoy 46060 are invaluable for the validation of EPWS/NFS performance. However, the discontinuance of the data on 25 AUG 05 without prior announcement on the NDBC Website is a big loss, and makes it impossible   to   assess   the   complete   seasonal   cycle   of   variability   of   EPWS/NFS velocity in the Central Sound (note that EPWS/NFS starts on 23 FEB 05) Access to OSRI's planned Lagrangian field experiment for AUG 07 is essential for skill assessment of EPWS­POM HIGHLIGHTS OF ACCOMPLISHMENTS:  1) A student seminar entitled as “Helmholtz Resonance of Semi­enclosed Seas” was   presented  in February  2006  in RSMAS   The   seminar  was  focused on  the physical   mechanism   and   application   of   barotropic   and   baroclinic   Helmholtz resonances  in  semi­enclosed seas   As   an example,   the  Helmholtz   resonance   in PWS   was   studied   and   detected   from   both   observed   and   simulated   coastal   sea levels and transport through HE. The Helmholtz resonance model can also be used to determine the response of  PWS spatial mean sea level to atmospheric pressure loading,   which   indicates   a     maximum   response   near   the   Helmholtz   resonance frequency   (period   ca     hrs),   an   isostatic   response   for   lower   frequencies,   and almost no response for higher frequencies .  2) Assistance with the real­time operation of both PWS/NFS and EPWS/NFS has continued, and the latest forecasts are updated daily via Internet at http://epws­ nfs.rsmas.miami.edu.  3) To first order,  the simulated CSLs generally agree well with NOS tide gauge observations at Cordova, Valdez and Seward (Fig. 1). However,   the differences between observations and simulations   may have amplitudes of 0.5 m or more during spring tides (Fig. 2), a phenomenon that requires further analysis to be understood   The   most   energetic   peaks   in   the   power   spectra   of   CSLs, corresponding   to   diurnal   and   semi­diurnal   tides,   are   consistent   between observations and simulations with nearly the same magnitude (Fig. 3). The peak for diurnal tides is broader in the observations than that in the simulations. Other than   tidal   periods   and   the   Helmholtz   resonance,   EPWS/NFS   produces   less energetic variations in CSL by an order of magnitude 4) Observed seasonal cycles of SST at all NOS stations and NDBC buoys are well simulated   by   EPWS/NFS   with   the   occurrence   of   maximum   SST   in   AUG   and minimum   SST   in   MAR   (Fig   4)   At   46060,   PWS/NFS,   on   the   other   hand, underestimates   the   observed   SST   by   a   maximum   of     C o  difference   (Fig   5) During summer 2005, one significant surface cooling event is misrepresented in PWS/NFS simulation, which in contrast, is precisely followed by EPWS/NFS. At GAK1, the EPWS/NFS monthly­mean temperature profile has structure similar to that   of   the   observed   monthly   climatology   for   the   upper   150   m   (Fig   6)   Both indicate the progressive delay of the occurrence of maximum temperature with water depth during seasonal warming. In the middle of October, a temperature inversion; i.e., a layer of warmer water under cooler water, occurs in both the simulations and the climatology, consistent with freshening in the upper layer that maintains hydrostatic stability on the monthly time scale.  5)  The transports through HE and MS are nearly balanced, highly coherent, and generally   out  of   phase   for   periods   longer   than   ca   30   hrs   (Fig   7)   At   periods shorter than ca. 10 hrs, the HE and MS transports are generally in phase and not perfectly coherent. There is a transition period band between 10 and 30 hrs where coherence is relatively low and phase varies rapidly.  6) As another application, EPWS/NFS time­depth velocity structure at a single point in HE was used to emulate a single moored ADCP moored. The  results indicate that a single ADCP might not be sufficient to estimate HE transport. On the other hand, two moored ADCPs significantly improves the   accuracy of the estimated HE transport (Fig. 8) 7)   The   subtidal   EPWS/NFS   simulated   surface   currents   in   Central   PWS   are dominated by mesoscale variability. A typical cyclonic eddy on 1MAR05 and an anticyclonic   eddy   on   1SEP05   (Fig   9)   are   displayed   as   examples   of   synoptic (“snapshot”)  surface   current   maps,     From   preliminary  examination  of  synoptic maps on a day­by­day basis for a year, the mesoscale variability changes rapidly: eddies typically form in Central Sound, translate northwestward, and dissipate in 20 to 30 da 8)   Cross­sectional   monthly   mean   temperature,   salinity,   density,   and   velocity structures   at   HE     are   examined   (Fig   10)   Surface   warming   and   freshening commences in MAY and continues  until AUG; then the surface water begins to cool and become saltier  The water column remains stratified  throughout the year in temperature, salinity, and density, though it is weaker in the surface layer in winter   than   summer,   as   is   to   be   expected.The   isopycnals   are   tilted   from   the horizontal (indicative of baroclinic flow) and in different directions (indicative of subsurface   extrema   in   the   flow)   In   most   months,   there   is   three­layered   flow: inflow in the surface and bottom layers and outflow in the intermediate layer These flow structures are fundamental to the dynamics of   PWS, including the ventilation (i.e., renewal or exchange) of its waters PRELIMINARY CONCLUSIONS  1) Both PWS/NFS and EPWS/NFS continue to be fully operational in a highly automated fashion with real­time atmospheric forcings from RAMS and OBCs from Global­NCOM 2) The Helmholtz resonance model can be used to determine the response of PWS spatial mean sea level to spatially­averaged atmospheric pressure loading, which crucially depends on the Helmholtz resonance frequency (period of ca. 6 hrs) of PWS 3)   EPWS/NFS   is   superior   to   PWS/NFS,   based   on   comparisons   of   surface temperature and time series of vertical profiles of horizontal velocity in Central Sound 4)  Overall, EPWS/NFS agrees well with observed coastal sea levels and surface temperatures at NDBC and NOS stations, as well as the climatological monthly temperature profiles at GAK1.  5) Coherence and phase of EPWS/NFS volume transports at HE and MS indicates a dependence on period: nearly balanced and out of phase at periods greater than 30 hrs, nearly in phase at periods less than 10 hrs, and a phase transition band between 10 to 30 hrs of low coherence 6) Emulation of moored ADCPs with detailed EPWS/NFS velocity structure at HE suggests   that   using   two   ADCPs   (rather   than   one)   significantly   improves   the estimation accuracy 7)     The   subtidal   EPWS/NFS   simulated   surface   currents   in   Central   Sound   are dominated by  mesoscale variability with a life cycle of the order of 1 mo 8) At HE, the simulated monthly mean transects of velocity components and the mass field (i.e., temperature, salinity, and density) for 2005 indicate that three-layer flow (viz., into PWS in the surface and bottom layers and out of PWS in the intermediate layer) is typical throughout most of the year, and that the upper layer stratification is stronger in summer than winter, as is to be expected Figure 1: Comparisons of Coastal Sea Levels (CSLs) between observations at NOS tide gauges (red) and EPWS/NFS (blue) during 07/19 ­ 08/18/2005: (a) Cordova; (b) Valdez; and (c) Seward Figure 2: Differences between simulated and observed CSLs during 07/19 ­ 08/18/2005:  (a) Cordova, (b) Valdez, and (c) Seward Figure 3: Power spectra for CSLs: (a) Cordova; (b) Valdez; and (c) Seward Figure 4: Comparisons between observed (red) and EPWS/NFS simulated (blue) SST at selected locations: (a) NOS Valdez; (b) NOS Cordova; (c) NDBC buoy 46060; (d) NDBC buoy 46061; (e) NDBC buoy 46081; (f) NDBC buoy 46076 Figure 5: Comparisons between observed (red), EPWS/NFS (blue) and PWS/NFS (green) simulated (blue) SST at 46060   Figure 6: Observed (upper) and simulated (bottom) monthly-mean temperature at various depths at GAK1 Observed monthly climatology is based on 30year CTD measurements, and simulated monthly-mean is from EPWS/NFS running during MAR2005-MAR2006 Figure 7: Coherence of one-year original volume transports (blue) between HE and MS: (a) magnitude; (b) phase For comparison, coherence of oneyear detided volume transports (red) is also shown: (c) magnitude; (d) phase Figure 8: Monthly-mean volume transport through HE: (1) EPWS/NFS simulated; (2) one-point ADCP estimated (as in Vaughan et al 1997); (3) one-point ADCP emulated (full depth); (4) one-point ADCP emulated (partial depth); and (5) two-point ADCP emulated EPWS/NFS simulated monthly-mean volume transport through MS (6) is also shown Figure 9: EPWS/NFS simulated surface current in Central Sound on 01 March (upper) and 01 September (bottom) 2005; Figure 10.1: EPWS/NFS simulated monthly-mean temperature transect at HE in 2005 NOTE: JAN & FEB are from 2006 because the present implementation (w/Global NCOM OBCs)of EPWS did not start until FEB 2005 Figure 10.2: Same as above but for salinity Figure 10.3: Same as above but for density Figure 10.4: Same as above but for northward velocity OSRI Quarterly Progress Report (JUL through SEP 2006) Part II - Budget Report 06-10-01 Budget Category Budget Direct Costs Personnel 20,000 Travel Contractual Commodities Equipment Subtotal Direct Costs 20,000 Indirect 5,000 Project Total 25,000 Quarter Expenses 3159.00 0 0 3159.00 789.75 3948.75 Cumulative Expenses 20000.00 0 0 20000.00 5000.00 25000.00 Balance Remaining 0 0 0 0 ... Figure 10.4: Same as above but for northward velocity OSRI Quarterly Progress? ?Report (JUL through SEP 2 006) Part II - Budget Report 06- 10-01 Budget Category Budget Direct Costs Personnel 20,000 Travel... buoy 4 6060 ; (d) NDBC buoy 4 6061 ; (e) NDBC buoy 46081; (f) NDBC buoy 46076 Figure 5: Comparisons between observed (red), EPWS/NFS (blue) and PWS/NFS (green) simulated (blue) SST at 4 6060   Figure 6: Observed... However, no performance information for these measurements has been provided, and the quality control of the data is unknown The ADCP measurements at NDBC buoy 4 6060  are invaluable for the validation of EPWS/NFS performance. However, the discontinuance of the data on 25 AUG