Source: W:\DATA\CRUISE\ATWAICE_PS131_2022\MR_SN324_Odin\NC\DAT_010.nc Format: netcdf4 Global Attributes: title = 'Dissipation measurements from a Slocum glider in Fram Strait, July 2022' platform = 'sub-surface glider' conventions = 'CF-1.6, ACDD-1.3, ATOMIX-1.0' history = 'Version 1' area = 'Arctic Ocean, Fram Strait' geospatial_lat_min = 78.9979 geospatial_lat_max = 78.9979 geospatial_lon_min = 7.8783 geospatial_lon_max = 7.8783 geospatial_vertical_min = 0 geospatial_vertical_max = 1000 geospatial_vertical_positive = 'down' time_coverage_start = '2022-07-06T19:00:16Z' time_coverage_end = '2022-07-06T19:23:29Z' creator_name = 'Fer, Ilker' creator_email = 'ilker.fer@uib.no' creator_url = 'https://www.uib.no/gfi' institution = 'University of Bergen' authors = 'Fer, Ilker; Elliott, Fiona' project = 'ATWAICE' cruise = 'PS131' vessel = 'Polarstern' principal_investigator = 'Fer, Ilker' contact = 'ilker.fer@uib.no' references = 'https://atomix.app.uib.no/ Lueck, R., I. Fer, C. E. Bluteau, M. Dengler, H. P., R. Inoue, A. LeBoyer, S.-A. Nicholson, K. Schulz, and C. Stevens (2024), Best practices recommendations for estimating dissipation rates from shear probes, Frontiers in Marine Science, 11, https://doi.org/10.3389/fmars.2024.1334327. Krahmann, Gerd (2023) GEOMAR FB1-PO Matlab Slocum glider processing toolbox. https://doi.org/10.3289/SW_4_2023.' acknowledgements = 'This data set is made possible by the funding from the Research Council of Norway, and the Office of Naval Research Global, award number N62909-22-1-2023.' keywords = 'Arctic Ocean, Fram Strait, glider, mixing, turbulence, dissipation rate, microstructure, shear probes' source = 'sub-surface glider' license = 'http://creativecommons.org/licenses/by/4.0/' instrument = 'MicroRider-1000LP' instrument_serial_number = 324 instrument_sample_rate = 512 instrument_sampling_mode = 'continuous' profiling_direction = 'glide' aoa = 3 fname = 'D:\WDATA\CRUISE\ATWAICE_PS131_2022\MR_SN324_Odin\P\DAT_010.P' gradC_method = 'high_pass' gradT_method = 'high_pass' hotel_file = 'Odin_hotelfile_forODAS.mat' speed_cutout = 0.02 speed_tau = 3 time_offset = 0 vehicle = 'slocum_glider' temperature_source = 'Found within hotel file.' shearprobe_sensitivity_correction_temperature = 5 shearprobe_sensitivity_correction_factor = 0.85 speed_source = 'Hotel file' fields_from_hotel = 'speed,W,depth,P,P_CTD,T_CTD,S_CTD,aoa,pitch,roll,fin,lon,lat' setupfilestr = '; Standard configuration setup.cfg file for a MicroRider on a TWE Slocum glider. ; Created by RSI, 2015-10-13 ; Any line that starts with a semicolon, ";", is a comment and is ignored by ; software. Likewise, everything to the right of a semicolon is ignored. ; Use this feature to leave notes and to indicate that you have made changes ; to this file. Indicate the date (YYYY-MM-DD), your name and a brief ; description of your changes. ; MicroRiders are internally recording instruments. ; Edited for TeledyneWebb MR1000 SN324, 2019-03-22 by RSI AB ; Edited pressure coefficients to zero at RSI by subtracting 0.91 from coeff. 0 2019-03-25 ; Sensors shear and temperature have nominal values input in the setup file. ; Edited for Polarstern deployment MR1000 SN324, 2021-06-29 by FE ; The first section is the [root] section. It determines the data ; acquisition parameters. It does not need to be declared explicitly. rate = 512 ; The sampling rate of fast channels prefix = dat_ ; The base name of your data files. A 3-digit ; file number is appended to this base name. ; The limit is 8 characters total for internally ; recording instruments. disk = /data ; The directory for the data files. Use /data only. recsize = 1 ; The size of a record in seconds no-fast = 6 ; number of fast "columns" in the address matrix (see below). no-slow = 2 ; number of slow "columns" in the address matrix. ; ----------------- ;This section presents the address [matrix] of your instrument and ; automatically ends the [root] section above. The first columns are "slow" ; channels as defined by the "no-slow" parameter in the [root] section. ; The remainder are "fast" columns ("no-fast"). [matrix] num_rows=8 row01 = 255 0 1 2 5 7 8 9 row02 = 32 40 1 2 5 7 8 9 row03 = 41 42 1 2 5 7 8 9 row04 = 4 6 1 2 5 7 8 9 row05 = 10 11 1 2 5 7 8 9 row06 = 12 0 1 2 5 7 8 9 row07 = 0 0 1 2 5 7 8 9 row08 = 0 0 1 2 5 7 8 9 ; -------------------- ;This section identifies your instrument. Only the vehicle is important. [instrument_info] vehicle = vmp ; up- and down-profiling model = mr_1000 ; the actual model sn = 324 ; the serial number of the instrument ; -------------------- ; The next section is optional and can be expanded. Do not use the parameter "id = ". [cruise_info] operator = Ilker Fer, Fiona Elliott project = Polarstern Cruise June 2022 ship = Polarstern leg = glider = Odin ; -------------------- ; Next come the [channel] sections. These are used to convert your data ; into physical units, and to save them into a mat-file. ; They also determine the name given to various signals ; in your data file. Please, stick to the convention of ; RSI because data visualization using the RSI Matlab Library of functions ; assumes particular names. However, data will be converted into physical ; units regardless of the name of the channels. If you change the names, ; then data visualization and further processing is your responsibility. ; A list of typical channel addresses (id) and their names and functions ; is at the end of this file. ; Each channel section consists of a part that is unique to your instrument. ; It does not need to be changed. The second part is dependent on your ; sensors (shear probes, FP07 thermistors, etc.) and must be updated ; whenever you change a probe. ; The ground reference channel. [channel] id = 0 ; the channel address, 0 to 255. Listed in the [matrix] section. name = Gnd ; the name it will have in the mat-file. type = gnd ; the algorithm used to convert raw data into physical units. coef0 = 0 ; the coefficients required for conversion. None in this case. ; -------------- ; The piezo-vibration sensors [channel] id = 1 name = Ax type = piezo [channel] id = 2 name = Ay type = piezo ; ----------------- ; The thermistor channels ; without pre-emphasis [channel] id=4 name=T1 type=therm ; instrument dependent parameters adc_fs = 4.096 adc_bits= 16 a =-8.4 b = 0.99881 G = 6 E_B = 0.68229 ; sensor dependent parameters. To be changed by user. SN = T2115 beta_1 = 3143.55 beta_2 = 2.5e5 T_0 = 289.301 cal_date= ; units = [C] ; with pre-emphasis [channel] id = 5 name = T1_dT1 type = therm ; instrument dependent parameter diff_gain = 0.929 ; without pre-emphasis [channel] id = 6 name = T2 type = therm ; instrument dependent parameters adc_fs = 4.096 adc_bits= 16 a =-14.8 b = 0.9984 G = 6 E_B = 0.68207 ; sensor dependent parameters. To be changed by user. SN = T2220 beta_1 = 3143.55 beta_2 = 2.5e5 T_0 = 289.301 cal_date= ; units = [C] ; with pre-emphasis [channel] id = 7 name = T2_dT2 type = therm diff_gain = 0.919 ; ----------------- ; The shear probe channels [channel] id = 8 name = sh1 type = shear ; instrument dependent parameters adc_fs = 4.096 adc_bits = 16 diff_gain = 0.925 ; sensor dependent parameters. To be changed by user. sens = 0.0755 SN = M2469 cal_date = 2021-10-21 [channel] id = 9 name = sh2 type = shear ; instrument dependent parameters adc_fs = 4.096 adc_bits = 16 diff_gain = 0.947 ; sensor dependent parameters. To be changed by user. sens = 0.0799 SN = M2470 cal_date = 2021-10-21 ; ----------------- ; The pressure transducer ; without pre-emphasis [channel] id = 10 name = P type = poly ; instrument dependent parameters coef0 = 1.34 ;offset reading to zero. 2.25(coef0) - 0.91(p.ch. reading)= 1.34 coef1 = 0.058466 coef2 = 3.329e-8 cal_date = 2019-03-22 ;units = [dBar] ; with pre-emphasis [channel] id = 11 name = P_dP type = poly ; instrument dependent parameters diff_gain = 20.68 ; pressure transducer voltage [channel] id = 12 name = PV type = poly ; instrument dependent parameters coef0 = 4.096 coef1 = 1.25e-4 ; units = [V] ; ----------------- ; Battery voltage or power supply voltage [channel] id = 32 name = V_Bat type = voltage ; instrument dependent parameters G = 0.1 adc_fs = 4.096 adc_bits = 16 ; units = [V] ; ----------------- ; The ADIS precision inclinometer with built in thermometer [channel] id = 40 name = Incl_Y type = inclxy ; instrument dependent parameters coef0 = 0 coef1 = 0.025 ; units = [degree] [channel] id = 41 name = Incl_X type = inclxy ; instrument dependent parameters coef0 = 0 coef1 =-0.025 ; units = [degree] [channel] id = 42 name = Incl_T type = inclt ; instrument dependent parameters coef0 = 624 coef1 =-0.47 ; units = [C] ; ------------------ ; This is a list of typical channels (addresses) and their signals ; that are currently available for a MicroRider on a TWE Slocum glider. ; id Name - rate - Signal ; ------------------------------------------------------------------- ; 0 Gnd - slow - Reference ground ; 1 Ax - fast - horizontal acceleration in the direction of the pressure port or ON/OFF magnet ; 2 Ay - fast - horizontal acceleration orthogonal to the direction of the pressure port ; 4 T1 - slow - Temperature from Thermistor 1 without pre-emphasis ; 5 T1_dT1 - fast - Temperature from Thermistor 1 with pre-emphasis ; 6 T2 - slow - Temperature from Thermistor 2 without pre-emphasis ; 7 T2_dT2 - fast - Temperature from Thermistor 2 with pre-emphasis ; 8 sh1 - fast - velocity derivative from shear probe 1 ; 9 sh2 - fast - velocity derivative from shear probe 2 ; 10 P - slow - pressure signal without pre-emphasis ; 11 P_dP - slow - pressure signal with pre-emphasis ; 12 PV - slow - voltage on pressure transducer ; 32 V_Bat - slow - Battery or power supply voltage ; 40 Incl_Y - slow - Inclinometer, rotation around the y-axis ; 41 Incl_X - slow - Inclinometer, rotation around the x-axis ; 42 Incl_T - slow - Inclinometer, its temperature ; 255 sp_char - slow - special Character that always returns 32752D or 7FF0H and ; is used to test the integrity of communication. ; End of setup configuration file. ; ' date = '06-Jul-2022 19:00:16' time_reference_year = 0 profile_dir = 'glide' fs_slow = 64.0041 fs_fast = 512.0327 fft_length_sec = 2 diss_length_sec = 10 overlap_sec = 5 fft_length = 1024 diss_length = 5120 overlap = 2560 fit_order = 3 goodman = 1 f_AA = 98 profile_min_W = 0.15 profile_min_duration = 36 profile_min_P = 1 HP_cut = 0.25 despike_sh = [8 0.3 0.04] despike_A = [8 0.3 0.04] despike_shear_fraction_limit = 0.15 FOM_limit = 1.4 diss_ratio_limit = 2.772 despike_shear_iterations_limit = 8 min_pitch_threshold = 15 refine_section = 0 vibrations_removed_indices = [52301 52302 52303 ... Output truncated. Text exceeds maximum line length for Command Window display. vibrations_removed_percent = 4.9375 spectral_model = 'Lueck' variance_resolved_limit = 0.6 fit_2_isr = 1.5e-05 f_limit = Inf num_vibration_goodman = 2 num_fft_segments = 9 spectrum_std = 0.52457 cast = 10 PMAX = 103.9004 LON = 7.8783 LAT = 78.9979 date_created = '2024-05-11T15:02:48Z' date_modified = '2024-05-11T15:02:48Z' summary = 'Ocean microstructure measurements were obtained from a Rockland Scientific (RSI) MicroRider (MR, serial number 324) attached to an electric Slocum glider. The glider Odin is a 1000-m electric Teledyne Webb Slocum glider (G3, serial number 775). The glider was operated close to the marginal ice zone, west of Spitsbergen, during the ATWAICE cruise on board Polarstern (PS131) in July 2022. The glider mission started on 6 July 2022 and ended on 2 August 2022. In addition to the turbulence package, the glider was equipped with a pumped Seabird conductivity-temperature (CTD) sensor. Both the CTD and the MR were configured to sample during dives and climbs of the glider. The dissipation rate was measured using two airfoil shear probes. The dataset has been processed and formatted in accordance with the SCOR Working Group ATOMIX guidelines and recommendations. One NetCDF (NC) file per instrument's native file (typically one file between consecutive surfacings of the glider) is provided. Each provided NC file is organized in four hierarchical groups including continuous time series of data converted into physical units, cleaned time series used for spectral analysis, wavenumber spectra, and dissipation rate estimates. The first group also includes time series, matched with the MR time, of longitude, latitude, temperature, salinity and flight parameters from the glider. The grouped NC files are large and may be impractical to download and merge. There are 208 files in total (file numbers 10 to 217). For users only interested in the dissipation estimates and other time-averaged profiles, we also provide two separate NC files with all dissipation rate (and other related parameters) profiles and 1-s averaged sensor data, including flight parameters, collated into one file each. For more detailed information, please refer to the comments within the data file.' comment = 'Ocean turbulence data were collected using a Rockland Scientific (RSI) MicroRider (MR-1000, serial number 324) attached to a Slocum electric glider as platform. The glider Odin is a 1000-m electric Teledyne Webb Slocum glider (G3, serial number 775). It was deployed on 6 Jul 2022 18:00 UTC and recovered on 2 Aug 2022. The payload included a pumped Seabird conductivity-temperature (CTD41CP, SN9545) and the MR turbulence package. The MR was fitted with two shear probes (S1=M2469, S2=M2470) and two thermistors (T1=T2115, T2=T2220) for measuring turbulence microstructure. Both the CTD and the MR were configured to sample during dives and climbs of the glider. The glider was operated close to the marginal ice zone, west of Spitsbergen, during the ATWAICE cruise on board Polarstern (PS131). Some interruptions in the data collection of the MR occurred (for example, for about 15 hours from 7 July 16:00, and on 25 July between 04:00 and 07:00) due to mission aborts. The data from the MR include measurements from 2 shear probes, 2-axis piezo-accelerometers (vibration), an inclinometer (pitch and roll) and a pressure transducer. The turbulence and vibration channels were sampled at a rate of 512 per second, while the other channels were sampled at 64 per second. The glider was operated with fixed battery positions during dives and climbs to reduce vibrations from the servo mode. Glider grounded twice during the segment on 18 July afternoon, due to altimeter being set too deep (200 m), this was corrected during next surfacing. The glider did not ground during any subsequent surfacings. The glider hit the sea ice on 31 July, approximately 11:50 UTC (by the end of DAT_217.P), when all probes of the MicroRider were broken. In total 208 files are processed (file numbers 10 to 217) out of a total of 217, excluding the short files when the glider was on deck or at the surface, and the files using the servo mode. The 208 files resulted in 636 sections. A section (a more general term for a profile) is a continuous part of the time series that has been selected for dissipation estimates. One file can have multiple sections, for example one section each from the successive dive and climb parts of the time series. The processing of the data and the format of this data set follows the recommendations and guidelines of the SCOR Working Group 160, ATOMIX (https://atomix.app.uib.no/), as decribed in Lueck et al. (2024). The processing was based on the standard Matlab routines provided by Rockland Scientific, which were adjusted for the ATOMIX recommendations. One NetCDF (NC) file per instrument's native file (one file between consecutive surfacings of the glider) is provided. Each NC file includes four hierarchical groups: L1_converted : time series from all sensors converted into physical units L2_cleaned : selected signals that are filtered and/or de-spiked before spectral analysis. Time stamp and length of the signals are the same as in L1. L3_spectra : wavenumber spectra from shear probes and vibration sensors L4_dissipation: dissipation estimates together with quality control parameters The glider (the so-called hotel), in addition to the temperature and salinity, also recorded roll and pitch. Together with the angle of attack and flow speed past sensors estimates using a hydrodynamic flight model, the hotel data are also included in L1_converted. The glider data are processed using the GEOMAR Matlab Slocum glider processing toolbox (Krahmann, 2023). Spectral calculation and dissipation rate estimate details are given in the attributes and processing parameters. Initial processing using 4-s fft length resulted in low-wavenumber contamination of the shear spectra. To avoid this, spectra are obtained using 2-s fft length. The short fft length, however, is not ideal for resolving low dissipation rates. Dissipation estimates are obtained over 10 s segments, overlapping by 5 s (50% overlap). Detailed data processing parameters and choices can be found in the attributes. Shear and vibration spectra, their complex cross-spectra, and the cleaned shear spectra using the Goodman method are provided. L4 includes estimates from both shear probes, using the cleaned spectra, along with a final estimate obtained by averaging over estimates that passed the quality checks, and quality control parameters. We used figure of merit (FOM) and mean absolute deviation (MAD) relative to the Lueck model spectrum. Data quality flags for dissipation estimates are summarized in the attributes of the variable EPSI_FLAGS within the L4 group. Any final dissipation estimate, EPSI_FINAL, failing the data quality control is reported as NaN. However, individual dissipation estimates from each probe are accessible in the EPSI parameter. Substantial data losses occurred in shear probe measurements when the glider's altimeter was activated during dives, at variable depths depending on the total water depth. These instances are visible in the data as gaps in EPSI_FINAL and with large (typically >0.2) values of DESPIKE_FRACTION_SH (refer to attributes for description). We applied a despike_shear_fraction_limit of 0.15, and users may want to apply additional quality screening. Furthermore, for the glider data we used an inclusive FOM threshold of 1.4 (i.e., relatively large deviations from the model spectrum are accepted). For dissipation estimates less than 1e-10 W/kg, we relaxed this threshold by a factor of two (to 2.8), as this parameter is not well-constrained for low dissipation rates. We observed systematically larger FOM values with decreasing dissipation rates, most with marginally acceptable estimates. This choice was made to retain noise-level estimates instead of introducing gaps in the data. Users may want to apply additional quality screening. In processing of individual files, we only applied an automated quality screening, using the threshold values given in the attributes. Because each file includes data sampled at full rate at two levels and their spectra in the third group, the grouped NC files are large and may be impractical to download and merge. For users only interested in the dissipation estimates and other time-averaged profiles, we provide two separate NC files containing all dissipation rate sections (along with other related parameters) and 1-second averaged sensor data including flight parameters, collated into one file each. These files contain long, 1-dimensional time series records. Data in the collated files are not gridded in time or pressure. Each data point has its own time stamp and pressure value, with time increasing monotonically from the start of the first section. Sections where the glider ascends (climbs) will therefore have pressure values decreasing with time. When producing the merged files, we performed additional quality screening, and updated the flag values, for eventual malfunctioning probes, altimeter effects and abrupt flight behavior changes, and used only good data (i.e., quality flags are applied). More details can be found in the description and attributes of the two merged NC files.' citation = 'Fer, Ilker; Elliott, Fiona (2024). Dissipation measurements from a Slocum glider in Fram Strait, July 2022. [Dataset], Norwegian Marine Data Centre, https://doi.org/10.21335/NMDC-2000742369.' Dimensions: TIME = 713728 N_SHEAR_SENSORS = 2 TIME_SPECTRA = 246 N_WAVENUMBER = 513 N_GLOBAL_VALUES = 1 TIME_SLOW = 89216 N_VIB_SENSORS = 2 N_TEMP_SENSORS = 2 N_GRADT_SENSORS = 2 Groups: /L1_converted/ Attributes: time_reference_year = 0 vehicle = 'slocum_glider' profile_dir = 'glide' fs_slow = 64 fs_fast = 512 f_AA = 98 date = '06-Jul-2022 19:00:16' cast = 10 PMAX = 103.9004 LON = 7.8783 LAT = 78.9979 Variables: TIME Size: 713728x1 Dimensions: /TIME Datatype: double Attributes: standard_name = 'time' axis = 'T' units = 'Days since 0000-01-00T00:00:00Z' long_name = 'Serial date number' calendar = 'proleptic_gregorian' comment = 'Standard MATLAB serial date number. It represents the fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar. 1 January noon is day 1.5.' SHEAR Size: 713728x2 Dimensions: /TIME,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'sea_water_velocity_shear' units = 's-1' long_name = 'rate of change of cross axis sea water velocity along transect measured by shear probes' TIME_SLOW Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'time' units = 'Days since 0000-01-00T00:00:00Z' axis = 'T' long_name = 'Serial date number' calendar = 'proleptic_gregorian' comment = 'Standard MATLAB serial date number. It represents the fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar. 1 January noon is day 1.5.' TIME_ELAPSED_SEC Size: 713728x1 Dimensions: /TIME Datatype: double Attributes: standard_name = 'time' long_name = 'time elapsed' units = 's' PRES Size: 713728x1 Dimensions: /TIME Datatype: double Attributes: standard_name = 'sea_water_pressure' units = 'decibar' long_name = 'Sea water pressure, equals 0 at sea-level' PRES_SLOW Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'sea_water_pressure' units = 'decibar' long_name = 'Sea water pressure, equals 0 at sea-level' VIB Size: 713728x2 Dimensions: /TIME,/N_VIB_SENSORS Datatype: double Attributes: standard_name = 'platform_vibration' units = 'm s-2' long_name = 'platform vibration detected by piezo-accelerometers' TEMP Size: 713728x2 Dimensions: /TIME,/N_TEMP_SENSORS Datatype: double Attributes: standard_name = 'sea_water_temperature' units = 'degree_Celsius' long_name = 'sea water temperature in-situ ITS-90 scale' TEMP_HOTEL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'sea_water_temperature' units = 'degree_Celsius' long_name = 'sea water temperature in-situ ITS-90 scale' comment = 'Measured by the sensor of the hotel (e.g., a glider)' GRADT Size: 713728x2 Dimensions: /TIME,/N_GRADT_SENSORS Datatype: double Attributes: standard_name = 'derivative_of_seawater_temperature_wrt_z' units = 'degree_Celcius m-1' long_name = 'derivative of sea water temperature with respect to depth' comment = 'It is the spatial derivative, derived from the rate of change of temperature and divided by the profiling speed' LON Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'longitude' units = 'degree_east' long_name = 'longitude' LAT Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'latitude' units = 'degree_north' long_name = 'latitude' PITCH Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_pitch_angle_fore_up' units = 'degree' long_name = 'Positive pitch represents thefront of the platform rising as viewed by an observer on top of the platform facing forward' PITCH_HOTEL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_pitch_angle_fore_up' units = 'degree' long_name = 'Positive pitch represents thefront of the platform rising as viewed by an observer on top of the platform facing forward' comment = 'Measured by the sensor of the hotel (e.g., a glider)' ROLL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_roll_angle_starboard_down' units = 'degree' long_name = 'Positive roll represents the right side of the platform falling as viewed by an observer on top of the platform facing forward' ROLL_HOTEL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_roll_angle_starboard_down' units = 'degree' long_name = 'Positive roll represents the right side of the platform falling as viewed by an observer on top of the platform facing forward' comment = 'Measured by the sensor of the hotel (e.g., a glider)' PSAL_HOTEL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'sea_water_practical_salinity' units = '1' long_name = 'Sea water practical salinity' comment = 'Measured by the CTD sensor of the hotel (e.g., a glider)' FIN_HOTEL Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_fin_angle' units = 'degree' long_name = 'Fin angle from the hotel' AOA Size: 89216x1 Dimensions: /TIME_SLOW Datatype: double Attributes: standard_name = 'platform_angle_of_attack' units = 'degree' long_name = 'Angle of attack, the angle between the glider principal axis and the glider path' /L2_cleaned/ Attributes: time_reference_year = 0 vehicle = 'slocum_glider' profile_dir = 'glide' fs_fast = 512 profile_min_W = 0.15 profile_min_duration = 36 profile_min_P = 1 HP_cut = 0.25 despike_sh = [8 0.3 0.04] despike_A = [8 0.3 0.04] despike_shear_fraction_limit = 0.15 despike_shear_iterations_limit = 8 date = '06-Jul-2022 19:00:16' cast = 10 PMAX = 103.9004 LON = 7.8783 LAT = 78.9979 Variables: TIME Size: 713728x1 Dimensions: /TIME Datatype: double Attributes: standard_name = 'time' units = 'Days since 0000-01-00T00:00:00Z' axis = 'T' long_name = 'Serial date number' calendar = 'proleptic_gregorian' comment = 'Standard MATLAB serial date number. It represents the fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar. 1 January noon is day 1.5.' SHEAR Size: 713728x2 Dimensions: /TIME,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'sea_water_velocity_shear' units = 's-1' long_name = 'rate of change of cross axis sea water velocity along transect measured by shear probes' comment = 'de-spiked and high-pass filtered' PSPD_REL Size: 713728x1 Dimensions: /TIME Datatype: double Attributes: standard_name = 'platform_speed_wrt_sea_water' units = 'm s-1' long_name = 'Platform speed with respect to sea water' SECTION_NUMBER Size: 713728x1 Dimensions: /TIME Datatype: int32 Attributes: standard_name = 'unique_identifier_for_each_section_of_data_from_timeseries' units = '1' long_name = 'A unique indentifier counter defining sections of the time series from the fast channels extracted for dissipation estimates' VIB Size: 713728x2 Dimensions: /TIME,/N_VIB_SENSORS Datatype: double Attributes: standard_name = 'platform_vibration' long_name = 'platform vibration detected by a pair of piezo-accelerometers' comment = 'de-spiked and high-pass filtered' /L3_spectra/ Attributes: time_reference_year = 0 fs_fast = 512 fft_length_sec = 2 diss_length_sec = 10 fft_length = 1024 diss_length = 5120 overlap = 2560 goodman = 1 HP_cut = 0.25 date = '06-Jul-2022 19:00:16' cast = 10 PMAX = 103.9004 LON = 7.8783 LAT = 78.9979 Variables: N_FFT_SEGMENTS Size: 1x1 Dimensions: /N_GLOBAL_VALUES Datatype: int32 Attributes: standard_name = 'number_of_fft_segments' units = '1' long_name = 'Number of FFT segments used in each spectrum estimate' N_VIB_SENSORS Size: 1x1 Dimensions: /N_GLOBAL_VALUES Datatype: int32 Attributes: standard_name = 'number_of_vibration_sensors_used_for_cleaning_spectra' units = '1' long_name = 'Number of vibration or acceleration sensors used for cleaning of shear spectrum with the Goodman algoritm' SPEC_STD Size: 1x1 Dimensions: /N_GLOBAL_VALUES Datatype: double Attributes: standard_name = 'standard_deviation_uncertainty_of_shear_spectrum' units = '1' long_name = 'statistical uncertainty (standard deviation) of the natural logarithm of spectrum of shear' TIME Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'time' units = 'Days since 0000-01-00T00:00:00Z' axis = 'T' long_name = 'Serial date number' calendar = 'proleptic_gregorian' comment = 'Standard MATLAB serial date number. It represents the fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar. 1 January noon is day 1.5.' PRES Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'sea_water_pressure' units = 'decibar' long_name = 'Sea water pressure, equals 0 at sea-level' SH_SPEC Size: 246x513x2 Dimensions: /TIME_SPECTRA,/N_WAVENUMBER,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'shear_probe_spectrum' units = 's-2 cpm-1' long_name = 'cyclic wavenumber spectrum of sea water velocity shear' KCYC Size: 246x513 Dimensions: /TIME_SPECTRA,/N_WAVENUMBER Datatype: double Attributes: standard_name = 'cyclic_wavenumber' units = 'cpm' long_name = 'wavenumber along the direction of instrument motion in cycles per meter' PSPD_REL Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'platform_speed_wrt_sea_water' units = 'm s-1' long_name = 'Platform speed with respect to sea water' SECTION_NUMBER Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: int32 Attributes: standard_name = 'unique_identifier_for_each_section_of_data_from_timeseries' units = '1' long_name = 'A unique indentifier counter defining sections of the time series extracted for dissipation estimates' TEMP Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'sea_water_temperature' units = 'degree_Celsius' long_name = 'sea water temperature in-situ ITS-90 scale' SH_SPEC_CLEAN Size: 246x513x2 Dimensions: /TIME_SPECTRA,/N_WAVENUMBER,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'shear_probe_spectrum_clean' units = 's-2 cpm-1' long_name = 'cleaned cyclic wavenumber spectrum of sea water velocity shear' VIB_SPEC Size: 246x513x2 Dimensions: /TIME_SPECTRA,/N_WAVENUMBER,/N_VIB_SENSORS Datatype: double Attributes: standard_name = 'vibration_sensor_spectrum' units = '1' long_name = 'vibration spectrum from vibration sensors' /L4_dissipation/ Attributes: time_reference_year = 0 fs_fast = 512 fft_length_sec = 2 diss_length_sec = 10 fft_length = 1024 diss_length = 5120 overlap = 2560 goodman = 1 HP_cut = 0.25 despike_shear_fraction_limit = 0.15 FOM_limit = 1.4 diss_ratio_limit = 2.772 despike_shear_iterations_limit = 8 date = '06-Jul-2022 19:00:16' cast = 10 PMAX = 103.9004 LON = 7.8783 LAT = 78.9979 Variables: TIME Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'time' units = 'Days since 0000-01-00T00:00:00Z' axis = 'T' long_name = 'Serial date number' calendar = 'proleptic_gregorian' comment = 'Standard MATLAB serial date number. It represents the fractional number of days from a fixed, preset date (January 0, 0000) in the proleptic ISO calendar. 1 January noon is day 1.5.' EPSI Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'specific_turbulent_kinetic_energy_dissipation_in_sea_water' units = 'W kg-1' long_name = 'dissipation rate of turbulent kinetic energy per unit mass in sea water estimated from individual shear probes' EPSI_FINAL Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'specific_turbulent_kinetic_energy_dissipation_in_sea_water' units = 'W kg-1' long_name = 'dissipation rate of turbulent kinetic energy per unit mass in sea water averaged using all accepted shear probes' KMAX Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'maximum_wavenumber_used_for_estimating_turbulent_kinetic_energy_dissipation' units = 'cpm' long_name = 'maximum wavenumber for integration of shear spectrum' KMIN Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'minimum_wavenumber_used_for_estimating_turbulent_kinetic_energy_dissipation' units = 'cpm' long_name = 'minimum wavenumber for integration of shear spectrum' N_S Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: int32 Attributes: standard_name = 'number_of_spectral_points_used_for_estimating_turbulent_kinetic_energy_dissipation' units = '1' long_name = 'number of spectral points used for estimating turbulent kinetic energy dissipation' comment = 'it is the same for the integration or the fit method' SECTION_NUMBER Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: int32 Attributes: standard_name = 'unique_identifier_for_each_section_of_data_from_timeseries' units = '1' long_name = 'A unique indentifier counter defining sections of the time series extracted for dissipation estimates' PSPD_REL Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'platform_speed_wrt_sea_water' units = 'm s-1' long_name = 'Platform speed with respect to sea water' METHOD Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: int32 Attributes: standard_name = 'method_used_for_estimating_turbulent_kinetic_energy_dissipation' units = '1' long_name = 'method for dissipation rate estimation' comment = '0 is spectral integration in the viscous subrange. 1 is spectral fit to the inertial subrange.' PRES Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'sea_water_pressure' units = 'decibar' long_name = 'Sea water pressure, equals 0 at sea-level' TEMP Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'sea_water_temperature' units = 'degree_Celsius' long_name = 'sea water temperature in-situ ITS-90 scale' FOM Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'figure_of_merit' units = '1' long_name = 'Ratio of the MAD of the spectrum to the 97.5 percentile of the expected MAD for the number of spectral points used to estimate the rate of dissipation' comment = 'If the number of spectral points is N, and the expected standard deviation of the natural logarithm of spectrum of shear is sig, expected MAD is sigx(0.8+(1.25/sqrt(N))). If the spectrum is calculated using number of FFT segments Nf, and cleaned using Nv vibration signals, sig = sqrt ( 5/4 ((Nf - Nv)^(-7/9))).' MAD Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'mean_absolute_deviation' units = '1' long_name = 'mean absolute deviation (MAD) of the natural logarithm of the shear spectrum from the logarithm of a reference spectrum for the estimated rate of dissipation' comment = 'MAD of the spectrum is calculated using the wavenumbers upto KMAX, relative to the model spectrum, using: e.g., mean(abs(log(observed_spectrum/model_spectrum)))' VAR_RESOLVED Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'variance_resolved' units = '1' long_name = 'variance resolved in the spectra used for the estimate rate of dissipation' EPSI_STD Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'expected_standard_deviation_of_the_logarithm_of_the_dissipation_estimate' units = '1' long_name = 'For estimates in the viscous subrange, EPSI_STD = sqrt(5.5 / (1 + (Lf/4)^(7/9))), whereLf = (L/Lk)(VAR_RESOLVED^(3/4)), and L is the data length in meters used for spectral estimate, Lk is the Kolmogorov length, and VAR_RESOLVED is the variance resolved in the spectra used for the estimate rate of dissipation.' KVISC Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'kinematic_viscosity_of_water' units = 'm2 s-1' long_name = 'Kinematic viscosity of sea water' DESPIKE_FRACTION_SH Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'fraction_of_shear_data_modified_by_despiking_algorithm' units = '1' long_name = 'fraction of data, within a segment, that was modified by the despiking algorithm for the shear probes' DESPIKE_FRACTION_AA Size: 246x2 Dimensions: /TIME_SPECTRA,/N_VIB_SENSORS Datatype: double Attributes: standard_name = 'fraction_of_vibration_data_modified_by_despiking_algorithm' units = '1' long_name = 'fraction of vibration or acceleration data, within a segment, that was modified by the despiking algorithm' DESPIKE_PASS_COUNT_SH Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: double Attributes: standard_name = 'number_of_despike_passes_for_shear_probes' units = '1' long_name = 'the number of passes ran with despiking routine to obtain a clean times series of shear probes. One value per section per probe' TRANS_ERR_FRACTION Size: 246x1 Dimensions: /TIME_SPECTRA Datatype: double Attributes: standard_name = 'transmission_error_fraction' units = '1' long_name = 'data transmission error fraction in a dissipation estimate segment' EPSI_FLAGS Size: 246x2 Dimensions: /TIME_SPECTRA,/N_SHEAR_SENSORS Datatype: int32 Attributes: standard_name = 'dissipation_qc_flags' units = '1' long_name = 'quality control coding for dissipation estimate from each shear probe ' conventions = 'ATOMIX, shear probes group' flag_values = [0 1 2 4 8 16 32 64 128] flag_meanings = '0: Good, 1: Poor figure of merit (FOM>FOM_limit), 2: Large fraction of data with spikes (despike_shear_fraction > despike_shear_fraction_limit), 4: Anomalously large disagreement between dissipation estimates from probes (|log(e_max)-log(e_min)|> diss_ratio_limit * EPSI_STD), 8: Too many iterations of despiking routine (despike_shear_iterations > despike_shear_iterations_limit), 16: Insufficient variance resolved (VAR_RESOLVED>