A Metzger Background Ambitions for Offshore Development in the Arctic No precedent in Chukchi and Beaufort How to design an offshore structure in the region Design standards were nonexistent ID: 999594
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1. Met-ocean parameters for portions of the Chukchi and Beaufort SeasA Metzger
2. BackgroundAmbitions for Offshore Development in the ArcticNo precedent in Chukchi and BeaufortHow to design an offshore structure in the region?Design standards – were nonexistentEngineering design criteriaA great deal of dataNot much information for engineers
3. BackgroundAmbitions for Offshore Development in the ArcticDevelopment of a normative documentISO 19906 Standard: Petroleum and Natural Gas Industries – Arctic Offshore StructuresAPI: RPN 2 document
4. BackgroundISO 19906 Standard: Petroleum and Natural Gas Industries – Arctic Offshore StructuresReliability-based design standardHigh probability of non-exceedanceOffshore environmental demands
5. BackgroundEnvironmental demands – arctic; offshoreISO 19906 provides reference tables [see ISO]
6. BackgroundEnvironmental demands – arctic; offshoreISO 19906 provides reference tablesNot in a reliability formatUser of ISO 19906 must determine their own values for design
7. BackgroundEnvironmental demands – arctic; offshoreUser of ISO 19906 must provide their own values for designIndustry conducted extensive field campaignsMultiple seasons.Tremendous cost and effortCollected a large amount of dataTechnically proprietaryHowever, a large amount was released Raw data
8. BackgroundEnvironmental demands – arctic; offshoreUser of ISO 19906 must provide their own values for designRegulatory agenciesPermit reviewOversightDo not have the resources available to industryNeeded a basis for diligent review and oversight
9. BackgroundEnvironmental demands – arctic; offshoreUser of ISO 19906 must provide their own values for designa basis for diligent review and oversightA great deal of data and scientific information existsNot [necessarily] in a format consistent with the NormativeAvailable data/ information is dispersed
10. BackgroundEnvironmental demands – arctic; offshorePurpose of this effortCollate readily available met-ocean dataProvide bulk statistics Quick-reference material for regulators
11. ApproachAcquire readily available meteorological and oceanographic data for the regionPhysical measurementsSatellite-derived data not consideredOutput from modeling not included
12. ApproachNarrative for each sourceE.g.:Prudhoe Bay.csvDate uploaded 1/15/2015. Organized as follows: Year, Month, Day, Hour (UTC), Minute, Latitude (N), Longitude (E), Elevation (m), Temperature (deg C), Dew Point (deg C), Relative Humidity (%), Wind Speed (m/s), Wind Direction (deg), Station Pressure (hPa), Sea-Level Pressure (hPa), Altimeter (in Hg), Downward Shortwave Radiation (W/m^2), Downward Longwave Radiation (W/m^2), 1-Hour Accumulated Precipitation (mm), 6-Hour Precipitation (mm), 24-Hour Precipitation (mm), Snow Depth (cm)Note: Values of -999 are NULL
13. ApproachData vetted by regional subject matter expertsMeterological – Oceana Francis (UH Manoa)Oceanographic – AkkA, LLC (Peter Winsor; Hank Statscewich)Individual records were codedConverted to common file type: .csvTYYYYMMSSS0000 Description:T data type: M = meteorological; O = oceanographic; S = Sea-iceYYYY Year data collection was completed (a sample of data may cross into an adjacent year; sets of data should not cross multiple years)MM Month data collection was completed (or month at end of data set); 01, 02, 03, ….10, 11, 12SSS three-letter code for instrument used to collect data; e.g., satellite (sat); Buoy (buo), RDCP (rdc), ADCP (adc) etc.0000 letter/number to designate the origin, project, campaign, source, etc.; make sure all four spaces have a letter or number; fill in unused spaces with 0s. It will be helpful to elaborate on these letters/ numbers in the data narrative.
14. ApproachPreliminary statistical surveySecondary vettingSpurious data removedBulk statisticsHistogramsRose plotsPdf fitsExtreme quantiles
15. Approachmeteorological data sets Beaufort: 28 recordsChukchi: 20 recordsEach record: A few months to several yearsYears 1999 to 2014Cut off at ~1999oceanographic data sets57 records of oceanographic parameters + Wave records: 7 records for Chukchi; none for Beaufort
16. Meteorological – Beufort SeaData source locations
17. Meteorological – Beufort SeaAir Temperature – monthly histograms Sampling rate: 5 min to 1 hour
18. Meteorological – Beufort SeaAir Temperature – monthly data No.Month# Data Pts.Min.1st5thMeanMedian95th99thMax1January103,339-47.7-42.2-38.5-26-25.9-14.2-4.232February94,006-47.9-41.6-38-24.7-25.4-10.1-4.63.33March90,604-45.1-39.7-36.7-26.4-26.5-15.3-11.1-3.54April75,545-37.7-29.6-25.8-14.9-14.9-4.20.88.15May84,891-28.5-18.5-14.3-5.3-4.723.9126June83,153-7.4-3.4-1.81.71.46.611.7207July89,579-3-0.415.65.212.115.623.38August129,157-3-0.40.95.14.611.715.425.29September153,307-11.6-3.6-2.11.91.56.910.317.510October114,205-25.9-17.1-12.1-4.6-3.80.33.211.311November101,957-38.8-35-29.5-15.9-15.4-5.7-3.12.812December112,462-41-37.9-34.1-20.4-19.6-7.6-3.53
19. Meteorological – Beufort SeaAir Temperature – monthly quantiles
20. Meteorological – Beufort SeaAverage Freezing/ Thawing Degree Days - monthly
21. Meteorological – Beufort SeaWind Speed
22. Meteorological – Beufort SeaWind Speed m/s No.Month# Data Pts.MeanMedian95th99th99.99thMax1January 94,125 6.65.71620.426.728.12February 89,927 6.96.215.218.426.5283March 93,993 6.55.813.917.522.624.14April 97,103 6.45.91317.122.525.45May 96,962 6.35.514.417.621.823.46June 94,300 6.86.214.218.124.225.97July 91,851 6.66.212.315.11921.88August 125,908 65.412.516.623.627.49September 153,434 7.26.315.519.227.427.510October 118,275 7.86.818.323.731.832.511November 107,413 6.75.516.820.427.628.812December 99,358 6.25.115.519.731.332.9
23. Meteorological – Beufort SeaWind Speed Quantiles m/s Max recorded: 32.9 m/s (73.6mph)
24. Meteorological – Beufort SeaWind Speed distribution fit = location parameter; 4.68454 = scale parameter 3.12926 = shape parameter; 0.0567011Max-Stable Distribution
25. Meteorological – Beufort SeaWind Direction (Direction wind is coming from)
26. Meteorological – Beufort SeaWind Direction - monthly
27. Meteorological – Beufort SeaWind Speed vs. Direction DirectionMean95th99th99.99thMax03.47.611.318.520.6303.98.410.922.523.7606.512.916.526.928.890917.520.729.732.512081721.931.332.91503.46.78.414.317.51803.37.19.51925.62104.29.111.91921.12405.311.315.422.423.82706.312.416.324.3283005.11114.327.428.43304.28.712.716.217.6
28. Meteorological – Beufort SeaWind Speed vs. Direction
29. Meteorological – Chukchi SeaData source locations
30. Meteorological – Chukchi SeaTemperature No.Month# Data Pts.Min.1st5thMeanMedian95th99thMax1January19,520-42.8-40.6-36.7-25.1-25.6-13.8-5.71.12February16,659-48.3-41.3-37.2-25.1-26-9.9-2.22.83March18,321-42.8-37.2-33.9-24.1-25-10-3.91.14April19,020-35.6-29.4-25.6-14.8-15.1-3.11.13.95May19,516-26.5-18.3-14.6-5.3-4.42.26.115.66June17,714-7.2-3.9-2.22.92.210.613.922.27July17,035-7.2-3.9-2.24.63.313.918.326.18August19,392-3.9-1.6-0.15.7513.317.222.89September19,717-13.8-5-2.81.81.27.81017.210October20,692-29.4-20-16.1-5.6-412.67.211November20,470-37.2-31.7-25.6-14.5-15-3.3-0.6512December19,133-41-35.7-32.2-20.1-20.6-6.1-2.23.9
31. Meteorological – Chukchi SeaTemperature
32. Meteorological – Chukchi SeaFreezing/ Thawing Degree-days
33. Meteorological – Chukchi SeaWind Speed – monthly quantiles
34. Meteorological – Chukchi SeaWind Direction
35. Meteorological – Chukchi SeaWind Speed vs. Direction
36. Oceanographic – Beaufort SeaData Source Locations
37. Oceanographic – Beaufort SeaCurrent Speedmeasurements taken hourly at depths of 3m ~ 9m Beaufort Sea# Data Pts.Mean cm/s95th99th99.9th99.99thMaxall data121,6178.129.652.681.4110.2124.6Simpson Cluster87,048932.455.486.1111.7124.6O200507adcSmit7,8836.428.254.865.375.775.7O200709adcCamd26,8495.620.634.963.774.675.2
38. Oceanographic – Beaufort SeaCurrent Direction(direction current is going to)
39. Oceanographic – Beaufort SeaSalinity
40. Oceanographic – Beaufort SeaWater Temperature – depth 8m to 16m the most common value.
41. Oceanographic – Chukchi Sea Waves: Data Source Locations
42. Oceanographic – Chukchi Sea Wave Height (yrs. 2010, 2011, 2012) No.Month# Data Pts.SWH,mnSWH,maxmax ht,mnmax ht,95th max ht,99thmax ht,99.9th maxht recorded7July1310.61.712.63338Aug.22561.23.41.94.25.15.55.69Sept.36081.54.22.44.86.17.38.410Oct.6851.342.245.45.95.9-All66801.34.22.24.65.87.18.4Sampling rate: 1 hourSignificant wave height: mean of highest 1/3 of waves in the hourMaximum wave height: highest wave (trough to crest) in the hour
43. Oceanographic – Chukchi Sea Wave Period MonthTminT1stT5thTmeanTmodeT95thT99thTmaxJul1.922.24.146.36.56.6Aug2.12.73.55.667.78.59.1Sep1.92.54.2779.511.112.5Oct3.43.84.76.568.39.19.5All1.92.63.86.469.110.512.5Longest wave period recorded in the hour
44. Oceanographic – Chukchi Sea Wave Direction
45. Oceanographic – Chukchi Sea Data Source Locations
46. Oceanographic – Chukchi Sea Current Speed Chukchi SeaMean Spd cm/s95th 99th99.9th 99.99thMax SpdEastern Data27.763.984.697.6111.5126.6Western Data11.833.950.573.288.394.7All Data20.756.380.295.6109.8126.6
47. Oceanographic – Chukchi Sea Current Direction
48. Oceanographic – Chukchi Sea Salinity
49. Oceanographic – Chukchi Sea Water temperature: 40m ~ 100m depth
50. Limitations – Meteorological DataRobust sample of wind and temperature measurementsrelevant to offshore structure designWind loadTemperatureFracture toughness requirementsCold temperature performance of materials; lubricants, etc. Unable to locate precipitation data - offshoreRainSnow
51. Limitations – Oceanographic DataOceanographic data is sparseReasonable samples; but close to shoreCurrentWater temperatureSalinityWave dataBeaufort: noneChukchi: limitedRelevant to offshore structure designLoads from currentForces from waves – gap that needs to be filled
52. RecommendationsMeteorologicalOffshore precipitation dataVerify offshore air temperature and windGood coverage in August, September, October (buoys deployed)Winter months not well covered offshoreOceanographicWave data for both regionsFill gap with modeling + data that is available?“Significant Wave Height” – not so significant in reliability-based designIdentify extremesUltimate limit state: 1/100Abnormal Limit State: 1/10,000Wave PeriodDominant wave periods must be known to mitigate dynamic forces
53. Comparison with ISO Annex B.7 Beaufort Meteorological ParametersISO 19906; Annex B.7BSEE E13PC00014 StudyParameterAverage Annual ValueRange of ValuesAverage Annual ValueRange of ValuesAir Temp.Max. (deg C)2010 to 30 10.5-3.5 to 25.2Min-30-20 to -40-28-3 to -47.9Freezing days45003500 to 55004180-Thawing days--440-Wind Speed2418 to 326.732.9 (max)Wind Direct.Winter 95 degrees-generally east-west year roundSummer50% N and NW-PrecipitationRainfall (mm)150100 to 200--Snowfall750600 to 1100--Visibility#days < 5mi20% of time---
54. Comparison with ISO Annex B.8 Chukchi Meteorological ParametersISO 19906; Annex B.8; NE RegionBSEE E13PC00014 StudyParameterAverage Annual ValueRange of ValuesAverage Annual ValueRange of ValuesAir Temp.Max. (deg C)1610 to 20 10.5-3.5 to 25.2Min-44-40 to -50-28-3.9 to -48.3Freezing days40003500 to 45004070-Thawing days--460-Wind Speed--5.827.7 (max)Wind Direct.Winter SE/25 to 30 deg-genrally E-NE to W-SWSummerE 25 to 40 deg-PrecipitationRainfall (mm)157100 to 200--Snowfall530300 to 700--Visibility#days < 5mi>30% of time20% to 40%--
55. Comparison with ISO Annex B.7 Beaufort Oceanographic ParametersISO 19906; Annex B.7BSEE E13PC00014 Study ParameterAverage Annual ValueRange of ValuesAverage Annual ValueRange of Values Waves (>100m water depth)max. wave ht (m)---- sig. wave height3.71.8 to 8.5-- period6.74.5 to 9.8-- Currentnear-surface max. cm/s4020 to 1008.1124.6 (max) bottom max.2 to 51 to 50-- Water SalinityAverage Surface, ppt2 to 300 to 3331.214 to 37 Water Temperaturesummer surface max (deg C)102 to 12at depth; Mean: -1.2; Mode: -1.8; Max: 5.7 summer surface ave5 to 70 to 10 Seabed geotech/ ice gougegouge depth (m)0.60.1 to 5see notes in Section 2 water dpeth (m)~30~50 Seimicmagnitude3 to 55.5 & 6.5
56. Comparison with ISO Annex B.8 Chukchi Oceanographic ParametersISO 19906; Annex B.7BSEE E13PC00014 StudyParameterAverage Annual ValueRange of ValuesAverage Annual ValueRange of ValuesWaves (>100m water depth)max. wave ht (m)--2.28.4sig. wave height3.71.8 to 8.51.3up to 4.2Period(s)6.74.5 to 9.86.41.9 to 12.5Currentnear-surface max. cm/s4020 to 10020.7126.6 (max)bottom max.2 to 51 to 50--Water SalinityAverage Surface, ppt2 to 300 to 3332.6 (at depth)24.7 to 40.4Water Temperaturesummer surface max (deg C)102 to 12at depth; Mean: -1.1; Mode: -1.8; Max: 9.1summer surface ave5 to 70 to 10Seabed geotech/ ice gougegouge depth (m)0.60.1 to 5see notes in Section 2water dpeth (m)~30~50Seimicmagnitude3 to 55.5 & 6.5
57. Final Report; Data Data: To be posted on a University server?North Slope Science Catalog?? Final Report: https://www.bsee.gov/research-record/tap-717-physical-oceanographic-and-meteorological-data-beaufort-and-chukchi-seas