OPR-P183-RA-13Shumagin Islands, AKShumagin Islands, AKNOAA Ship RAINIERH1259585 NM South of Simeonof IslandAlaskaUnited States400002013Richard T. Brennan, CDR/NOAANavigable Area2013-05-312013-07-172013-09-03Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCPacific Hydrographic BranchThe purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charts. All separates are filed with the hydrographic data. Any revisions to the Descriptive Report (DR) generated during office processing are shown in bold red italic text. The processing branch maintains the DR as a field unit product, therefore, all information and recommendations within the body of the DR are considered preliminary unless otherwise noted. The final disposition of surveyed features is represented in the OCS nautical chart update products. All pertinent records for this survey, including the DR, are archived at the National Geophysical Data Center (NGDC) and can be retrieved via http:// www.ngdc.noaa.gov/.NOAAThe survey area is referred to as Sheet 8: "5 NM South of Simeonof Island" within the Project Instructions (Figure 1). The area is 2.2 NM south of Simeonof Island and 3.7 NM east of Chernabura Island.54.8268555556159.40672777854.7335972222159.102497222H12595 survey limits.SupportFiles\Image 1.pngParts of the northeast corner of this survey did not reach the sheet limits; however, prior survey H12475 completely covers this area and there is significant overlap between the two surveys (Figure 2).H12475 overlap with H12595 sheet limits.SupportFiles\Figure 2 Overlap.pngSAR: Figure 2 contains a typo and the northern area pictured should read H12475, not H12473.The purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products.The entire survey is adequate to supersede previous data.Data acquired on survey H12595 met complete multibeam echosounder (MBES) coverage requirements, including the 5 soundings per node data density requirements outlined in section 5.2.2.2 of the HSSD (Figure 3) with one exception: The 1-meter surface fell slightly short of density requirements due to foul weather at the time of acquisition. Statistics were extracted from the density layer of each finalized surface in CARIS and examined in Excel. Overall, the required data density was achieved in 100.0% of the nodes by area (Figure 4).H12595 data density.SupportFiles\Image 2 Density.pngSummary table showing the percentage of nodes satisfying the 5 sounding density requirements, sub-divided by the appropriate depth ranges. Note: The final row has a unit of square meters, and sums the number of different resolution nodes into a common unit of area.SupportFiles\Image 3 Density Table.pngSAR: In review, the Density analysis was verified using a macro - FinalizedCSARSurfaceQA.py - distributed with NOAA's in-house software suite Pydro, which analyses values directly from the .csar surfaces and do not use intermediate applications or files. The results disagree with the values found in Figure 4. The 1m surface contains 12172/12909 nodes ( 94.29%) which pass the density requirement. The 2m surface contains 149459/150054 nodes (99.6%) which pass the density requirement, and the 4m surface contains 12625970/12629583 nodes (99.97%) which pass the density requirement.Complete multibeam echosounder (MBES) coverage was achieved within the limits of hydrography as defined in the Project Instructions with the following exceptions: Acoustic Shadowing: Almost all holidays were a result of acoustic shadowing (Figure 6). This effect was seen where data density on the 'dark' side of a feature or between features was too sparse to produce a surface at the appropriate resolution. All cases were investigated to assure that least depths were found. Coverage Gaps: Data acquisition during poor weather conditions resulted in coverage gaps, the largest of which is 116 meters by 8 meters (Figure 7). All of the coverage gaps are at a depth of 30 meters or greater, and are not navigationally significant.Subset exemplifying the acoustic shadows seen in the survey. SupportFiles\use_this_acoustic_shadow.pngLocation of largest coverage gap.SupportFiles\Figure 7 Coverage Gap.pngIn review, the reviewer used a 4m resolution to grid the surfaces for compilation because the 8m surface was unnecessary given the depths. When gridded according to the HSSD, gaps appeared - caused by bubble sweep raking the sonar face in inclement weather and disrupting very short, swath-wide segments of bathymetry. The gaps were investigated and found to contain no navigationally significant features. All remaining data is adequate to supersede charted data. Acquired survey coverage overlaid on Chart 16540. Scale shows depth in meters.SupportFiles\Figure 5 Overview.pngS2210510.300000002801017.000000002802050.900000002803025.000000002804044.00000029.000647.2000002904.512000059.112013-07-172013-07-182013-07-242013-08-022013-08-062013-08-082013-08-092013-08-102013-08-112013-09-022013-09-03All data for survey H12595 was acquired by NOAA Ship RAINIER and her four survey launches (2801, 2802, 2803, and 2804). The survey launches and ship acquired MBES depth soundings, sound speed profiles, and bottom samples.Refer 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.S221 (Rainier)23116.52801 (RA-4)283.52802 (RA-5)283.52803 (RA-3)283.52804 (RA-6)283.5Reson7125MBESKongsbergEM710MBESODIM Brooke Ocean (Rolls-Royce Group)MVP30Conductivity, Temperature, and Depth SensorODIM Brooke Ocean (Rolls-Royce Group)MVP200Conductivity, Temperature, and Depth SensorApplanixPOS-MV V4Vessel Attitude and Positioning SystemSeabirdSBE 19 PlusConductivity, Temperature, and Depth SensorSeabirdSBE 19Conductivity, Temperature, and Depth SensorResonSVP 71Sound Speed SystemResonSVP 70Sound Speed SystemMultibeam crosslines were acquired using the Reson 7125 on vessel 2801 (RA-4). A 4-meter CUBE surface was created using the mainscheme lines, while a second 4-meter CUBE surface was created using only crosslines, from which a difference surface was generated in CARIS at a 4-meter resolution (Figure 8). Statistics were then derived from the difference surface and are shown in Figure 9. The average difference between the depths derived from the mainscheme and crosslines was 0.04 meters (crosslines being shoaler) with a standard deviation of 0.17 meters. For the respective depths, the difference surface was compared to the allowable IHO accuracy standards (Figure 10). In total, 100.0% of the depth differences between H12595 mainscheme and crossline data are within allowable IHO accuracies (Figure 11).H12595 difference surface between the mainscheme and crosslines.SupportFiles\XL Difference.pngCrossline comparison with mainscheme lines.SupportFiles\Image 9 crossline.pngDepth differences between H12595 mainscheme and crossline data as compared to allowable IHO accuracy standards for the associated depths.SupportFiles\IHO difference.pngSummary table showing percentage of difference surface nodes between H12595 mainscheme and crossline data that meet allowable IHO accuracy standards for the respective depths.SupportFiles\Crossline IHOness Table.png00.045S2211.00.0528013.00.1528023.00.1528033.00.1528043.00.15Total propagated uncertainty values for survey H12595 were derived from a combination of fixed values for equipment and vessel characteristics, as well as field assigned values for sound speed uncertainties. Tidal uncertainties were provided by NOAA's Center for Operational Oceanographic Products and Services (CO-OPS), and were applied to depth soundings. Uncertainty values of submitted final grids were calculated in CARIS using the "Greater of the Two" of uncertainty and standard deviation (scaled to 95%). To visualize the locations in which accuracy requirements were met, for each finalized surface a custom "predicted IHO compliance" layer was created based on the difference between calculated uncertainty of the nodes and the allowable IHO uncertainty (Figure 12). To quantify the extent to which accuracy requirements were met, the preceding "predicted IHO compliance" layers were queried within CARIS and then examined in Excel (Figure 13). Overall, 100.0% by node and 100.0% by area of survey H12595 met the accuracy requirements stated in the HSSD. In addition to the usual a priori estimates of uncertainty, some real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H12595. Real-time uncertainties from both the EM710 and Reson 7125 were recorded and applied in post-processing. Applanix TrueHeave files are recorded on all survey vessels, which include an estimate of the heave uncertainty, and are applied during post-processing. Finally, the post-processed uncertainties associated with vessel roll, pitch, gyro and navigation are applied in CARIS HIPS via an SBET RMS file generated in POSPac.H12595 met IHO accuracy standards for 100.0% of the survey area.SupportFiles\IHO Uncertainty SFC.pngSummary table showing the percentage of nodes satisfying the indicated IHO accuracy level, sub-divided by the appropriate depth ranges. Note: The final row has a unit of square meters, and sums different resolution nodes into a common unit of area.SupportFiles\IHO Uncertainty Table.pngSAR: In review, the TPU analysis was verified using a macro - FinalizedCSARSurfaceQA.py - distributed with NOAA's in-house software suite Pydro, which analyses values directly from the .csar surfaces and do not use intermediate applications or files. The results disagree with some values found in DR Figure 13. The 1m surface contains 12909/12909 nodes (100%) which pass the density requirement. The 2m surface contains 149885/150054 nodes (99.89%) which pass the density requirement, and the 4m surface contains 12629395/12629583 nodes (99.99%) which pass the density requirement. It should be noted that node counts for surfaces in the DR's Figure 4 and Figure 13 do not agree, which is indicative of an incomplete analysis. Despite these errors, the review shows that surveyed data is of the highest order quality and adequate to supersede charted soundings.Three junction comparisons were completed for H12595. One survey (H12594) was acquired concurrently with this survey, and two surveys (H12473 and H12475) were completed in 2012 by NOAA Ship RAINIER (Figure 14). Depth comparisons were performed using CARIS difference surfaces and Subset Editor.H12595 junction overview.SupportFiles\H12595 Junctions.pngH12473400002012NOAA Ship RAINIERNWOverlap with survey H12473 ranges from 90 to 450 meters wide along the northwestern boundary of H12595 (Figure 15). Depths in the junction area range from approximately 10 to 60 meters. A difference surface analysis between CUBE depth layers for each survey showed H12595 to be an average of 0.04 meters deeper than H12473, with a standard deviation of 0.23 meters (Figure 16). This is well within IHO Order 1 accuracy at these depths.Junction between H12595 (blue) and H12473 (red).SupportFiles\H12473 Junction.pngDifference surface statistics between H12595 and H12473 CUBE depth layers (4m grid size). H12595 is an average of 0.04 meters deeper.SupportFiles\H12473 Junction Histogram.pngH12475400002012NOAA Ship RAINIERNEOverlap with survey H12475 ranges from 60 to 490 meters wide along the northeastern boundary of H12595 (Figure 17). Depths in the junction area range from approximately 36 to 66 meters. A difference surface analysis between CUBE depth layers for each survey showed H12595 to be an average of 0.09 meters deeper than H12475, with a standard deviation of 0.17 meters (Figure 18). This is well within IHO Order 1 accuracy at these depths.Junction between H12595 (blue) and H12475 (green).SupportFiles\H12475 Junction.pngDifference surface statistics between H12595 and H12475 CUBE depth layers (4m grid size). H12595 is an average of 0.09 meters deeper.SupportFiles\H12475 Junction Histogram.pngH12594400002013NOAA Ship RAINIERWOverlap with survey H12594 ranges from 160 to 460 meters wide along the western boundary of H12595 (Figure 19). Depths in the junction area range from approximately 35 to 60 meters. A difference surface analysis between CUBE depth layers for each survey showed H12595 to be an average of 0.09 meters shoaler than H12594, with a standard deviation of 0.12 meters (Figure 20). This is well within IHO Order 1 accuracy at these depths.Junction between H12595 (blue) and H12594 (brown).SupportFiles\H12594 Junction.pngDifference surface statistics between H12595 and H12594 CUBE depth layers (4m grid size). H12595 is an average of 0.09 meters shoaler.SupportFiles\H12594 Junction Histogram.pngSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.None ExistThere were no conditions or deficiencies that affected equipment operational effectiveness.Ellipsoid-to-Tidal Surface ComparisonUsing the GPS height determined from the SBET file, data from H12595 was referenced to the ellipse and gridded. As a QC tool an ERS to MLLW difference surface was created to identify artifacts. By differencing this ellipsoidally-referenced surface (ERS) from the traditional tidally-referenced surface, one should only see the ellipsoidal slope across the length of the survey. Any deviations from this slope would therefore be the result of an error intrinsic to either the ERS or tidal processing work flow. Misprojected SBETs, current induced dynamic draft, incorrect waterline measurements, corrupt TrueHeave files, or poorly-modeled water levels are all examples of artifacts that can be identified through the difference of the ERS and tidally referenced surfaces. The depth gradient between the MLLW and the ERS surfaces is expected to be similar in magnitude and position as the EGM2008-WGS84 geoid-ellipsoid separation model published by the National Geospatial-Intelligence Agency (NGA). In review, it was found that the two models compare well - exhibiting a signature northwest to southeast gradient of depth differences across the survey area - particularly considering the 2.5' resolution of the NGA surface and the expected differences between the geoid and MLLW (Figure 21). There are three notable artifacts apparent in the data; two lines indicated on the eastern side of the survey show a heave artifact, and a dark red line shows vertical offsets from surrounding data. Upon review, it was found that the two lines on the eastern side of the survey had missing TrueHeave records for small segments of each line. This created heave artifacts of ± 0.5 meters that were present at MLLW but not on the ellipse. TrueHeave was retained for these lines in order to improve the quality of the majority of the data (see B.3.1 Corrections to Echo Soundings). The dark red line indicates vertical offsets of up to 0.4 meters from surrounding data. These offsets are only present on the ellipse. Four lines were excluded from this difference surface due to problems with the application of SBETs (see C.3.3.1 Lines without SBETs). Difference surface between the ellipsoidally-referenced and tidally-referenced surfaces. Difference surface is overlaid on the EGM2008-WGS84 geoid-ellipsoid separation model with artifacts.SupportFiles\ERS Surface with Errors.pngSound Speed ArtifactsDespite casts being taken as frequently as every 15 minutes, with consideration to spatial distribution, sound speed artifacts were seen within the data. These artifacts occurred as "smiles" or "frowns" due to inadequately modeled refraction. In these areas, the outer beams were flagged as rejected to assist the gridding algorithm in bringing the surface back to better represent the true seafloor. Although this artifact exists within the data, it is within uncertainty standards specifications as stated within Section 5.1.3 of the HSSD. The Hydrographer finds that the data is adequate to supersede charted data (Figure 22).Example of sound speed artifact seen within H12595.SupportFiles\B.2.7 Sound Speed Artifacts.pngFor casts collected on S221, profiles were acquired using the Rolls Royce MVP200 approximately every 15 minutes or when recommended by "CastTime", a cast frequency program developed at the University of New Hampshire. All other launch sound speed profiles were acquired using the SBE-19 and SBE-19 plus CTDs at discrete locations at least once every four hours. A concatenated sound speed casts file was created for each vessel and applied to all H12595 survey lines using the "Nearest in Distance within (4 hours) Time" profile selection method. A total of 282 CTD casts were used (Figure 23).Distribution of sound speed profiles acquired for survey H12595.SupportFiles\Sound Speed Locations 3.pngModified EM710 Waterline Value: A routine part of acquisition with the EM710 is a measurement of the ship's waterline immediately before commencing operations, or immediately after any evolution that is suspected to impact said waterline (e.g. the deployment/recovery of launches); see DAPR. On DN218, however, a waterline measurement was taken that was suspected to be in error (-4.556 meters), likely due to large seas at the time of observation. This measurement was not in keeping with historic values and led to a vertical shift in the data acquired by the ship on this day. To address this, the waterline measurement taken two days later and under similar loading conditions (-4.707 meters) was used for DN218. This change was observed to improve vertical agreement with surrounding data and is documented in the HVF.All data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Backscatter data was acquired, but not formally processed by RAINIER personnel. However, periodic spot checks were performed to ensure backscatter quality. Backscatter was logged as .7k or .ALL files and submitted to NGDC, but is not included with the data submitted to the Branch.NOAA Profile V_5_3_2All data was processed using CARIS HIPS and SIPS 8.1.1. It should be noted that all Kongsberg EM710 data was intentionally processed without the Simrad Sound Velocity Correction (SVC) module. This was done in order to avoid a known error in the SVC module associated with reverse-mounted transducers. To accomplish this, a custom CARIS license file was used, which excluded the licensing for the Simrad SVC. For further details, refer to the DAPR.H12595_1mCUBE1990NOAA_1mComplete MBESH12595_2mCUBE2990NOAA_2mComplete MBESH12595_4mCUBE4990NOAA_4mComplete MBESH12595_8mCUBE8990NOAA_8mComplete MBESH12595_1m_0to20m_FinalCUBE1020NOAA_1mComplete MBESH12595_2m_18to40m__FinalCUBE21840NOAA_2mComplete MBESH12595_4m_36to80m_FinalCUBE43680NOAA_4mComplete MBESH12595_8m_72to100m_FinalCUBE872100NOAA_8mComplete MBESH12595_Combined_8mCUBE8990NOAA_8mComplete MBESDepth ranges for BASE surfaces, 4m Finalized, and 4m Combined surface (created in review for compilation) do not exceed 78m, and do not extend to 90m as stated in Table 9. A 4 meter base surface was created during SAR review. The H12595_MB_4m_MLLW_Combined file was used for final compilation.Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.Mean Lower Low WaterDiscrete ZoningSand Point, AK 945-9450 Bird Island, AK945-92519459450.tidVerified Observed9459251.tidVerified ObservedH12595CORF.zdfFinal2013-09-202013-11-20The tide station installed by RAINIER personnel on Bird Island, AK (945-9251) was used as the primary control for datum determination and as a source for water level reducers from 2348 UTC on 13 July (DN194) through 0436 UTC on 18 August (DN230). The National Water Level Observation Network (NWLON) tide station in Sand Point, AK (945-9450) served as a subordinate gauge during this time. During the time of acquisition when the Bird Island gauge was not operational, the NWLON tide station in Sand Point served as the primary gauge. A complete description of the vertical and horizontal control for this survey can be found in the accompanying Horizontal and Vertical Control Report (HVCR), submitted under separate cover.Tide note is appended to this report.North American Datum of 1983 (NAD83)UTM - Zone 04NSingle BaseBird IslandN/AIn conjunction with this project, a GPS base station was established by RAINIER personnel on Bird Island, AK; the station was operational from DN192 through DN207 and from DN222 through DN245. During the times when the Bird Island base station was not operational (DN208 through DN221 and DN246 through DN254), a Plate Boundary Observatory station on Chernabura Island (ChernaburaAK2008, AC12) was used for post-processing. There were two exceptions: On DN198 and DN199, there were several processing problems with the Bird Island base station; some of the data for these days was corrected using the Chernabura Island base station. Vessel kinematic data was post-processed with Applanix POSPac and POSGNSS software using Single Base processing methods described in the DAPR. Differential Global Positioning System (DGPS) correctors were used for horizontal control when the post-processing methods stated above were not possible (see C.3 Additional Horizontal or Vertical Control Issues). Kodiak, AK (313 kHz)Cold Bay, AK (289 kHz)Lines without SBETsSBETs could not be applied to Lines 0048_20130724_060218_Rainier and 0047_20130724_053305_Rainier acquired from vessel S221 DN205, and lines 2803_2013RA2221742 and 2803_2013RA2221802 acquired from vessel 2803 DN222 due to time extents not overlapping with the lines. DGPS correctors were retained for these lines. Inspection of the data in Subset Editor shows agreement with surrounding data.A comparison was made between survey H12595 and Chart 16540 using CARIS CUBE surfaces and a sounding layer. All data from H12595 should supersede charted data.165402528300000132010-102010-10-122010-10-30Comparison was performed with Chart 16540 (1:300000) using a CARIS sounding layer based on the combined 4-meter CUBE surface from H12595. During the comparison, it was observed that the charted rocks were not present. The northern portion of the survey has a least depth of 5 fathoms just south of the charted 7 fathom sounding. In addition, there are several areas shoaler than charted, the shoalest being 15 fathoms. These shoals do not pose a danger to navigation (Figure 24). Chart 16540 depth comparison in fathoms.SupportFiles\D.1.1 Chart Soundings.pngTable 16 indicates that Notice to Mariners and Local Notice to Mariners were not applied to chart 16540 prior to comparison with field work by the hydrographer. The chart used for comparison during office review and compilation was corrected through LNTM 09/13/2014 and NTM 9/23/2014.US3AK50M300000172011-06-292011-06-29falseENC US3AK50M was digitized from Chart 16540 and coincides with the raster. The depths on the ENC match the raster, and the comparison between survey H12595 and the ENC is equivalent to the preceding comparison with Chart 16540. The Hydrographer recommends that a sounding set derived from survey H12595 supersede charted depths.No AWOIS items were assigned for this survey.No Maritime Boundary Points were assigned for this survey.No charted features exist for this survey.No uncharted features exist for this survey.No Danger to Navigation Reports were submitted for this survey.No shoals or potentially hazardous features exist 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. Bottom samples were acquired in accordance with the Project Instructions and the HSSD. Twelve proposed bottom sample locations were included in the Project Reference File; all twelve samples were collected. All samples were labeled in accordance with the HSSD with S-57 attribution, and can be found in the Final Feature File (Figure 25). Bottom sample locations.SupportFiles\Bottom Samples.pngShoreline was not assigned in the Hydrographic Survey Project Instructions or Statement of Work.No prior survey comparisons exist for this survey.No Aids to navigation (ATONs) exist for this survey.No overhead features exist for this survey.No submarine features exist for this survey.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No significant features exist for this survey.No present or planned construction or dredging exist within the survey limits.No new surveys or further investigations are recommended for this area.No new insets are recommended for this area.As Chief of Party, Field operations for this hydrographic survey were conducted under my direct supervision, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.All 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.Richard T. Brennan, CDR/NOAACommanding Officer, NOAA Ship RAINIER2013-12-11Meghan McGovern, LT/NOAAField Operations Officer, NOAA Ship RAINIER2013-12-11James B. JacobsonChief Survey Technician, NOAA Ship RAINIER2013-12-11J.C. Clark, ENS/NOAAJunior Officer, NOAA Ship RAINIER2013-12-11