2016-05-26Chief of PartyLCDR Briana Welton, NOAA2016-05-26Field Operations OfficerLT Nicholas Morgan, NOAA2016-05-26Sheet ManagerPS Tyanne FaulkesAll field sheets, this Descriptive Report, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch.The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report.Field operations for this hydrographic survey were conducted under the direct supervision of the then Chief of Party, Commander Marc S. Moser, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.There were no conditions or deficiencies that affected equipment operational effectiveness.None ExistAll equipment and survey methods were used as detailed in the DAPR.H12839 MBES crossline data overlaid on mainscheme data, shown in grey.SupportFiles\H12839_MS-XL_Geographic.pngH12839 crossline difference statistics: mainscheme minus crossline.SupportFiles\H12839_MS-XL.pngA geographic plot of crosslines is shown in Figure 4. Crosslines were filtered to remove soundings greater than 45 degrees from nadir. To evaluate crossline agreement, two 2-meter surfaces were created: one from crossline depths, the other from mainscheme depths. These two surfaces were differenced using CARIS HIPS/SIPS. The 2.6 million nodes have a difference value range from -0.89 meters and 1.84 meters. The statistical analysis of the differences between the mainscheme and crossline surfaces is shown in Figure 5. The average difference between the surfaces is 0.06 meters with a standard deviation of 0.09 meters; Ninety-five percent of nodes agree within +/- 0.17 meters of the mean.H12839 sound speed profile locations.SupportFiles\H12839_SV_Locations.pngA total of 484 sound speed measurements were taken within the boundaries of H12839 (See Figure 14). These sound speed measurements were collected using the MVP-200 approximately every 30 minutes. Comparisons were made by the survey watch to assess sound speed variation in the water column. Sound speed corrections were applied in CARIS HIPS/SIPS using Nearest in Distance Within Time (NIDWT) of every 4 hours for the entire survey. Sound speed measurements related to H12839.SupportFiles\H12839_Refraction_1.pngRay tracing analysis.SupportFiles\H12839_Refraction_2.pngExample of two sound speed profiles from DN217 which were taken 18 minutes apart.SupportFiles\H12839_Refraction_3.pngExample where the surface shows signs of refraction in H12839.SupportFiles\H12839_Refraction_4.pngSubset of refraction data.SupportFiles\H12839_Refraction_5.pngRefraction issues due to environmental conditions exist in survey H12839. As shown in Figure 9, the likely culprit was the mid-water column thermocline which resides between 10 and 20 meters. This thermocline saw sound speed variations of up to 30 meters per second. A ray tracing uncertainty analysis was performed to help identify casts that exceeded the allowance for refraction as defined in Section 5.2.3.4 Error Budget Analysis for Depths (See Figure 10). The blue lines in the graph are consecutive cast comparisons and the red dots are the allowable vertical error due to refraction. In cases where the blue line exceeds the red dots, those are examples of where the estimations show the allowable refraction error is being exceeded. As we can see, refraction issues are present on data collected between DN217 to DN220 and DN235 to DN236. Sound speed casts were taken at a very frequent rate, yet refraction still was an issue, because it was believed that the sound speed variability in nature, specifically, the survey lines may have crossed a significant below-layer sound speed gradient. An example from DN217 shows two profiles which were taken only 18 minutes apart, yet the estimated outerbeam refraction error is 0.658m (See Figure 11). A number of methods were used to mitigate the refraction. Initially the sonars were being operated using its entire 140 degree swath. After an in port in Norfolk, VA the hydrographer instituted two changes: the use of Cast-Time to model these refraction issues and the decrease in swath width. This change most likely is the reason why data from DN238 and 239 do not exhibit the extreme refraction issues seen on the earlier days. To mitigate the impacts of refraction on data that was already collected, a number of methods were used. First, lines from DN217, DN219, and DN220 were filtered to 66 degrees on the port side for port lines and 66 degrees on the starboard side for starboard lines. Filtered lines were then inspected by the hydrographer to ensure they did not cause holidays or remove data from the tops of shoals or features. In areas this did occur, data was re-accepted by the hydrographer in subset editor. Secondly the hydrographer utilized Subset Editor in CARIS HIPS/SIPS to further eliminate poor data (See Figures 12 and 13). This did not eliminate all instances of refraction in H12839. Though the data does not meet allowable error budget for refraction, the surfaces do meet the Total Vertical Uncertainty requirements (See Section B.5.4 Total Vertical Uncertainty Analysis in this report for more information). Sound Speed ErrorsSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Junction associated with survey H12839.SupportFiles\H12839_Junctions_1.pngOne contemporary survey, to the west, junctions with H12839. See Figure 7 for further information.Difference surface statistics for H12839 and H12840.SupportFiles\H12839-H12840.pngSurvey H12839 junctions with its contemporary survey H12840. Nodes overlap approximately 200 meters to the west. The minimum and maximum depth difference between the two surveys is -1.07 meters and 1.14 meters respectively. Of the greater than 505 thousand overlapping nodes, the average difference is 0.14 meters with a standard deviation of 0.09 meters; Ninety-five percent of the differenced surface nodes are within +/- 0.17 meters of the mean, as shown in Figure 8.40000WNOAA Ship FERDINAND R. HASSLER2015H12840Sources of error data applied during CARIS processing.SupportFiles\H12839_uncertainty_source.pngTwo tidal models were available for water level corrections associated with survey H12839. A discrete tide zone file, produced by CO-OPS for project OPR-B304-FH-15, was provided to the field unit. Additionally, a vertical datum transformation (VDatum) model was delivered to the field unit in the project instructions. All data for survey H12839 were reduced to MLLW via VDatum. This model functioned as a gridded separation model for GPS tide computations with a 0.081 meter uncertainty. Final TPU calculations are derived from the following sources: VDatum separation model, sound velocity (MVP and surface sound velocimeter), HVF uncertainties, and SBET post processed uncertainty. Error data sources applied through CARIS processing software are listed in Figure 6.VDATUM0.1020.010.5S2501142.3823.55NOAA_2mH12839_MB_2m_MLLW2Complete MBESCUBE40.0023.55NOAA_2mH12839_MB_2m_MLLW_Final2Complete MBESCUBE42.3023.56NOAA_4mH12839_MB_4m_MLLW4Complete MBESCUBE42.3036.00NOAA_4mH12839_MB_4m_MLLW_Final4Complete MBESCUBEData density of the 2-meter finalized surface.SupportFiles\H12839_MB_2m_MLLW_Final_Density.pngData density of the 4-meter finalized surface.SupportFiles\H12839_MB_4m_MLLW_Final_Density.pngA density analysis was run to calculate the number of soundings per surface node. The results determined that 99.9% of all nodes contained five or more soundings which meets the data density specifications (See Figures 15 and 16).Data DensityTotal vertical uncertainty analysis for 2-meter finalized surface.SupportFiles\H12839_MB_2m_MLLW_Final_TVU_QC.pngTotal vertical uncertainty analysis for 4-meter finalized surface.SupportFiles\H12839_MB_4m_MLLW_Final_TVU_QC.pngPydro's Finalized CSAR QA tool was used to calculate the percentage of nodes which meet total vertical uncertainty (TVU) specifications. The resulting statistical analysis yielded 99.9% nodes both surfaces meet TVU specifications (See Figures 17 and 18). In addition, a custom layer was created for the finalized surfaces submitted in correlation with H12839. The layer was derived from the difference between the calculated uncertainties of individual nodes and the allowable uncertainty at the coupled node. Total Vertical Uncertainty AnalysisWithin the limits of H12839, one (1) sounding is flagged as designated. Designated SoundingsNOAA Profile V_5_3All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Backscatter was logged in RESON datagram 7008 snippets record in the raw .s7k files. The .s7k file also holds the navigation record and bottom detections for all lines of survey H12839. The files were paired with the CARIS HDCS data, imported, and processed using Fledermaus Geocoder Toolbox (FMGT). The FMGT projects and backscatter mosaic imagery is included in the field submission. The processed mosaic is formated as a geo-referenced tiff image per specifications. The following information is provided as metadata for the processing branch: Backscatter data processing and mosaicing performed in Fledermaus FMGT version 7.4.4b using Reson De-TVG plugins where appropriate. Backscatter data has a histogram range of 10 to -70dB Backscatter data is provided in separate layers broken down by survey vessel hull number and sonar operating frequency. H12839_S250_Port_400kHz | 4m resolution mosaic | Absorption Coefficient = 100dB/km H12839_S250_Stbd_400kHz | 4m resolution mosaic | Absorption Coefficient = 100dB/kmRefer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.7125ResonMBESPOS M/V 320 V5ApplanixPositioning and Attitude SystemMBX-4HemisphereSound Speed SystemMicroCTDAMLSound Speed SystemMVP-200Brooke OceanSound Speed SystemSVP-70RESONSound Speed SystemSBE 19+Sea BirdSound Speed SystemNOAA Ship FERDINAND R. HASSLERSupportFiles\Hassler_stern_bow_clean.png37.7S2503.77NOAA Ship FERDINAND R. HASSLER (S250), shown in Figure 3, acquired all surveyed soundings during operation for H12839H12839 Survey LimitsSupportFiles\H12839_SurveyLayout.pngSurvey H12839 was conducted in the Chesapeake Bay, with a sublocality of 36 miles East of Currituck Beach as shown in Figure 1.75.216372083336.199013333375.308189722236.5001421111Survey coverage was in accordance with the requirements listed above and in the HSSD.Complete Multibeam with BackscatterAll waters in survey area0080.208Mainscheme survey lines were run with a dual-head multibeam echosounder. Linear nautical miles were calculated using statistics from the port head.1112.76.5000000071.81112.7000000071.8S2502015-07-302015-07-312015-08-052015-08-072015-08-082015-08-102015-08-112015-08-182015-08-192015-08-202015-08-232015-08-24The entire survey is adequate to supersede previous data.Survey layout for OPR-D304-FH-15 over raster chart 12200.SupportFiles\H12839_ProjectLayout.pngSurvey limits were acquired in accordance with the requirements in the Project Instructions and the HSSD.The purpose of this project is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. In addition, this project will improve the chart for traffic navigating the Atlantic Ocean Channel and will support Bureau of Ocean Energy Management (BOEM) research in the area.LCDR Briana J. Welton, NOAA2015Atlantic Hydrographic BranchUTCUniversal Transverse Mercator (UTM)meters2015-10-19Multibeam Echo SounderMultibeam Echo Sounder Backscatter2015-07-302015-08-24Navigable AreaNOAA40000H12839North CarolinaUnited States36 Miles East of Currituck Beach1OPR-D304-FH-15Approaches to Chesapeake BayApproaches to Chesapeake BayNOAA Ship FERDINAND R. HASSLERNo Maritime Boundary Points were assigned for this survey. One new obstruction was identified with 100% multibeam data. See FFF for more information.ENC US3DE01M comparison.SupportFiles\H12839-US3DE01M.pngDifference surface between ENC US3DE01M and H12839.SupportFiles\H12839-US3DE01M_2.png4197062016-01-28false2016-01-2817US3DE01MENC soundings were extracted from the S-57 file and used to create an interpolated .csar surface. The interpolated surface was then differenced with the 4-meter finalized surface from survey H12839. The depth differences range from -12.87 to 11.25 meters. The high depth differences were determined to be the result of coarse resolution soundings extracted from the ENC. All other depth differences mirrored RNC depth differences, with a mean difference value of 0.19 meters, shown in Figure 22. In general, surveyed soundings were deeper than charted. Figure 23 shows a surface created by interpolating the differenced point cloud between the ENC and surveyed soundings. Negative values indicate areas where surveyed soundings are deeper than charted.ENC US4NC31M comparison.SupportFiles\H12839-US4NC31M.pngDifference surface between ENC US4NC31M and H12839.SupportFiles\H12839-US4NC31M_2.png800002014-10-09false2016-03-0718US4NC31MENC soundings were extracted from the S-57 file and used to create an interpolated .csar surface. The interpolated surface was then differenced with the 4-meter finalized surface from survey H12839. The depth differences range from -5.27 to 3.86 meters. The high depth differences were determined to be the result of coarse resolution soundings extracted from the ENC. All other depth differences mirrored RNC depth differences, with a mean difference value of -1.20 meters, shown in Figure 24. In general, surveyed soundings were deeper than charted. Figure 25 shows a surface created by interpolating the differenced point cloud between the ENC and surveyed soundings. Negative values indicate areas where surveyed soundings are deeper than charted.Chart 12200 comparison.SupportFiles\H12839_Chart12200_Comp.png2014-0541970612200512016-02-272016-02-23526A comparison was performed with Chart 12200 (1:419,706) using soundings derived from a 4-meter combined surface, shown in Figure 20. Most charted depths agree within 1-2 fathoms of H12839 surveyed soundings, with exception of the southeast portion of the survey. Chart 12204 comparison.SupportFiles\H12839_Chart12204_Comp.png2012-128000012204382016-02-272016-02-23527A comparison was performed with Chart 12204 (1:80,000) using soundings derived from a 4-meter combined surface. Most charted depths agree within 2-3 feet of H12839 surveyed soundings, with exception of the area shown below in Figure 21. No charted features exist for this survey.No Danger to Navigation Reports were submitted for this survey.No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits.Eight (8) bottom samples were acquired for this survey. See final feature file for more information.No shoals or potentially hazardous features exist for this survey.The hydrographer has compared a sounding plot from the surveyed area to the charted soundings. There are no charted contours to compare.No new insets are recommended for this area.No present or planned construction or dredging exist within the survey limits.No overhead features exist for this survey.No submarine features exist for this survey.ATONs were observed during H12839 survey operations. These aids were deemed to serve their intended purposes. No positioning was performed in the field or required from the project instructions.No platforms exist for this survey.Prior survey comparisons exist for this survey, but were not investigated.No ferry routes or terminals exist for this survey.No Significant Features exist for this survey.No new surveys or further investigations are recommended for this area.A limited shoreline investigation was required by the project instructions but no shoreline coincides with H12839.All vertical and horizontal control activities conducted during the course of this survey are fully addressed in the following sections. No separate HVCR is submitted.2015_D304_VDatum_NAD83_MLLWVDatumAll soundings submitted for H12839 has been reduced to MLLW using documented VDatum techniques.Mean Lower Low WaterExample of SBET interpolation for 2015_222_S250S. The anomalous data on the left has been edited in POSPAC AutoQC and the resultant SBET is seen on the right.SupportFiles\H12839_BeforeAfterSBET.pngOn occasion, the SBET altitude exhibited spikes which compromised the data's ability to meet TVU specifications. In these instances, the hydrographer utilized tools in Pydro's POSPAC Automated QC tool to interpolate the SBET (See Figure 19 for an example). The interpolated SBET was exported out of the POSPAC Automated QC tool, opened in POSPAC MMS, and exported again to ensure the SBET was in the correct datum (NAD83). The new SBET contains the prefix "interpolated" for easy identification. The following SBETs were interpolated for H12839: DN219 Starboard lines using interpolated_2015_219_S250S_b.sbet DN222 Starboard lines using interpolated_2015_222_S250S.sbet and 2015_222_S250S_b.sbet Interpolation of SBETsNorth American Datum of 1983 (NAD83)Single BaseSingle Base processing was the primary method used for Post Processed Kinematics (PPK) processing of Applanix TrueHeave data for Smooth Best Estimate of Trajectory (SBET) production. SBET files have been loaded for all lines for survey H12839 and are used to reduce acquired soundings to MLLW via HSD Operations Branch provided separation model.DUCK 3, Duck, NCNCDUUTM Zone 18NDriver, VA (289 kHz)DGPS was used for real-time positioning during acquisition. All lines submitted are corrected using post-processed horizontal solutions.