Local physical oceanographic and oxygen isotopic observations at Palmyra Atoll of the 2014-15 and 2015-16 El Nino events
Data files
Sep 14, 2023 version files 306.73 MB
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PALMYRA_D18OSW_2014-2016.mat
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PALMYRA_RAINFALL_2014-2016_WithIso_updatedfeb2018.mat
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PALMYRA_SALINITY_2014-2016.mat
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PalmyraAQD1848_RT4_201503-201508.mat
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PalmyraAQD2834_FR9_Aug2015.mat
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PalmyraAQD2839_FR7_Aug2015.mat
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PalmyraAQD2841_FR5_Aug2015.mat
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PalmyraAQD2914_FR9_201409_201503.mat
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PalmyraAQD5264_CH1_201409_201503.mat
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PalmyraAQD5308_FR5_201409-201503.mat
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PalmyraAQD5309_RT4_201409-201503.mat
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PalmyraAQD5327_FR7_201409_201503.mat
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PalmyraFR5_SBE2480data_sep2014-march2015.mat
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README.md
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SBE05601856_PalmyraFR7_Mar2016.mat
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SBE05601859_PalmyraFR9_Mar2016.mat
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SBE05601967_PalmyraRT4_Mar2016.mat
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SBE05601968_PalmyraCH1_Mar2016.mat
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SBE05601969_PalmyraFR5_Mar2016.mat
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SBE12812_2_PalmyraFR7_Mar2016.mat
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SBE12812_PalmyraFR7_Sep2015.mat
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SBE1856_PalmyraFR5_Nov2017.mat
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SBE1859_PalmyraFR9_Nov2017.mat
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SBE1940_PlmyraCH1_sep2014_march2015_copy.mat
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SBE1967_PalmyraCH1_Nov2017.mat
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SBE1968_PalmyraFR7_Nov2017.mat
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SBE1969_PalmyraRT4_Nov2017.mat
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SBE2141_PalmyraFR7_sep2014-march2015.mat
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SBE2142_PalmyraFR5_Sep2015.mat
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SBE2143_PalmyraFR5_Mar2016.mat
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SBE2143_PalmyraFR9_Sep2015.mat
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SBE2144_PalmyraCH1_Sep2015.mat
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SBE2144_PalmyraFR5_Nov2017.mat
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SBE2144_PalmyraRT4_1_Mar2016.mat
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SBE2144_PalmyraRT4_2_Mar2016.mat
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SBE2977_PalmyraCH1_Mar2016.mat
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SBE2977_PalmyraRT4_Nov2017.mat
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SBE2978_PalmyraRT4_Aug2015.mat
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SBE2980_PalmyraCH1_Nov2017.mat
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SBE37_2143_201609_PalmyraFR9.mat
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SBE37_2144_201609_RT4.mat
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SBE37_2977_201609_FR7.mat
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SBE37_2980_201609_PalmyraFR5.mat
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SBE56_1856_201609_PalmyraRT4_Sep2016.mat
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SBE56_1859_2016-09-21_PalmyraFR5.mat
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SBE56_1967_201609_PalmyraFR9_Sep2016.mat
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SBE56_1968_201609_CH1.mat
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SBE56_1969_2016-09-21_FR7.mat
Abstract
Paleoclimate reconstructions of El Nino/Southern Oscillation (ENSO) behavior often relies on oxygen isotopic records from tropical corals (δ18O). However, few reef-based observations of physical conditions during El Nino events exist, limiting our ability to interpret coral δ18O. Here we present physical and geochemical measurements from Palmyra Atoll (5.9◦N, 162.1◦W) from 2014-17, along with a data assimilation product using the isotope-enabled Regional Ocean Modeling System (isoROMS). Coral δ18O signals are comparably strong in 2014-15 and 2015-16; notably, over 50% of the signal is driven by seawater δ18O, not temperature. If a constant seawater δ18O: salinity was present, this would imply a comparable salinity anomaly during both events. However, salinity changes are much larger during 2014-15, indicating a highly nonstationary relationship. isoROMS then shows that advection strongly influences δ18O during both the 2014-15 and 2015-16 El Nino, driving differences in the salinity/seawater δ18O relationship. This demonstrates the need for considering ocean dynamics when interpreting coral δ18O.
README: Local physical oceanographic and oxygen isotopic observations at Palmyra Atoll of the 2014-15 and 2015-16 El Nino events
Experimental data used to construct the figures found in "Contrasting central equatorial Pacific oxygen isotopic signatures of the 2014/15 and 2015/16 El Nino events". This data was collected by a team from the University of Hawaii at Manoa, funded by NSF RAPID awards OCE-1446930 and OCE-1446274 to S. Stevenson and K. Cobb, with funds contributed by the NOAA Joint Institute of Marine and Atmospheric Research as well.
The full citation for the paper describing results from this field campaign is:
"Contrasting central equatorial Pacific oxygen isotopic signatures of the 2014/15 and 2015/16 El Nino events",
Stevenson, S., Cobb, K. M., Merrifield, M., Powell, B., Sanchez, S.,Nusbaumer, J., OConnor, G., Atwood, A. 2023, Geophysical Research Letters
Codes used for data processing in that paper are located at:
https://github.com/samanthastevenson/Palmyra_RAPID_2014-16
Methodological information: see the manuscript methods section or the methods section of the Dryad dataset (doi:10.7272/Q6XK8CS) for details. Briefly, data consist of information collected from moored sensors deployed at shallow coral reefs around Palmyra Atoll, along with samples of rainwater and seawater collected at various places around the atoll.
Locations of sites mentioned below are:
Temperature/salinity/currents
- RT4: 5.876N, 162.129W
- FR5: 5.869N, 162.075W
- FR9: 5.896N, 162.128N
- FR7: 5.897N, 162.078W
- CH1: 5.878N, 162.105W
Water samples
- FR7-Shore: 5.8926N, 162.0.0762W
- Strawn1: 5.8906N, 162.0933W
The temperature, salinity, and current data were collected using either Seabird (SBE) conductivity-temperature-depth sensors, or Aquadopp (AQD) acoustic Doppler current profilers. All SBE and Aquadopp files are stored in Matlab format.
Naming Conventions
There is one file per instrument, per deployment: filenames contain the numerical code associated with the instrument (e.g. SBE2978), the name of the site at which the instrument was deployed (see list above), and either the date range or the ending date of the deployment.
Temperature, salinity data: SBE37
RT4
SBE2978_PalmyraRT4_Aug2015.mat
- Size: 892 KB
- Variables: cond2978 = raw conductivity measurements sal2978 = salinity (units of psu) temp2978 = temperature (units of C) time2978 = time (Matlab datenum format)
SBE2144_PalmyraRT4_1_Mar2016.mat
- Size: 1.1 MB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) t = time (Matlab datenum format)
SBE2144_PalmyraRT4_2_Mar2016.mat
- Size: 315 KB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) t = time (Matlab datenum format)
SBE37_2144_201609_RT4.mat
- Size: 1.4 MB
- Variables: cond2144 = raw conductivity measurements sal2144 = salinity (units of psu) temp2144 = temperature (units of C) t2144 = time (Matlab datenum format)
SBE2977_PalmyraRT4_Nov2017.mat
- Size: 995 KB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) time = time (Matlab datenum format)
CH1
SBE1940_PlmyraCH1_sep2014_march2015 copy.mat
- Size: 1.7 MB
- Variables: cond1940 = raw conductivity measurements sal1940 = salinity (units of psu) temp1940 = temperature (units of C) time1940 = time (Matlab datenum format)
SBE2144_PalmyraCH1_Sep2015.mat
- Size: 1.4 MB
- Variables: cond2144 = raw conductivity measurements sal2144 = salinity (units of psu) temp2144 = temperature (units of C) time2144 = time (Matlab datenum format)
SBE2980_PalmyraCH1_Nov2017.mat
- Size: 1.1 MB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) time = time (Matlab datenum format)
FR7
SBE2141_PalmyraFR7_sep2014-march2015.mat
- Size: 1.4 MB
- Variables: cond2141 = raw conductivity measurements sal2141 = salinity (units of psu) temp2141 = temperature (units of C) time2141 = time (Matlab datenum format)
SBE12812_PalmyraFR7_Sep2015.mat
- Size: 1.6 MB
- Variables: cond12812 = raw conductivity measurements good_data12812 = indices corresponding to locations within data array of data not associated with dropouts or known issues sal12812 = salinity (units of psu) temp12812_68 = temperature (units of C), calibrated according to the International Practical Temperature Scale of 1968 temp12812_90 = temperature (units of C), calibrated according to the International Practical Temperature Scale of 1990 (note: negligible differences appear between temp12812_68 and temp12812_90) time12812 = time (Matlab datenum format)
SBE12812_2_PalmyraFR7_Mar2016.mat
- Size: 1.4 MB
- Variables: cond12812 = raw conductivity measurements sal12812 = salinity (units of psu) temp12812 = temperature (units of C) time12812 = time (Matlab datenum format)
SBE37_2977_201609_FR7.mat
- Size: 376 KB
- Variables: cond2977 = raw conductivity measurements sal2977 = salinity (units of psu) temp2977 = temperature (units of C) t2977 = time (Matlab datenum format)
FR5
PalmyraFR5_SBE2480data_sep2014-march2015.mat
- Size: 1.4 MB
- Variables: cond2480 = raw conductivity measurements sal2480 = salinity (units of psu) temp2480 = temperature (units of C) t2480 = time (Matlab datenum format)
SBE2142_PalmyraFR5_Sep2015.mat
- Size: 1.2 MB
- Variables: cond2142 = raw conductivity measurements good_data = indices corresponding to locations within data array of data not associated with dropouts or known issues sal2142 = salinity (units of psu) temp2142 = temperature (units of C) time2142 = time (Matlab datenum format)
SBE2143_PalmyraFR5_Mar2016.mat
- Size: 1.4 MB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) t = time (Matlab datenum format)
SBE37_2980_201609_PalmyraFR5.mat
- Size: 1.5 MB
- Variables: cond2980 = raw conductivity measurements sal2980 = salinity (units of psu) temp2980 = temperature (units of C) t2980 = time (Matlab datenum format)
SBE2144_PalmyraFR5_Nov2017.mat
- Size: 1 MB
- Variables: cond = raw conductivity measurements sal = salinity (units of psu) temp = temperature (units of C) time = time (Matlab datenum format)
FR9
SBE2143_PalmyraFR9_Sep2015.mat
- Size: 1.2 MB
- Variables: cond2143 = raw conductivity measurements good_data2143 = indices corresponding to locations within data array of data not associated with dropouts or known issues sal2143 = salinity (units of psu) temp2143 = temperature (units of C) time2143 = time (Matlab datenum format)
SBE37_2143_201609_PalmyraFR9.mat
- Size: 396 KB
- Variables: cond2143 = raw conductivity measurements sal2143 = salinity (units of psu) temp2143 = temperature (units of C) t2143 = time (Matlab datenum format)
Temperature data: SBE56
RT4
SBE05601967_PalmyraRT4_Mar2016.mat
- Size: 14.9 MB
- Variables: temp_1967 = temperature (units of C) t_1967 = time (Matlab datenum format)
SBE56_1856_201609_PalmyraRT4_Sep2016.mat
- Size: 14.4 MB
- Variables: temp1856 = temperature (units of C) t1856 = time (Matlab datenum format)
SBE1969_PalmyraRT4_Nov2017.mat
- Size: 26.2 MB
- Variables: temp = temperature (units of C) time = time (Matlab datenum format)
FR7
SBE05601856_PalmyraFR7_Mar2016.mat
- Size: 8.4 MB
- Variables: temp_1856 = temperature (units of C) t_1856 = time (Matlab datenum format)
SBE56_1969_2016-09-21_FR7.mat
- Size: 14.6 MB
- Variables: temp1969 = temperature (units of C) t1969 = time (Matlab datenum format)
SBE1968_PalmyraFR7_Nov2017.mat
- Size: 26.8 MB
- Variables: temp = temperature (units of C) time = time (Matlab datenum format)
FR5
SBE1856_PalmyraFR5_Nov2017.mat
- Size: 26.7 MB
- Variables: temp = temperature (units of C) time = time (Matlab datenum format)
CH1
SBE05601968_PalmyraCH1_Mar2016.mat
- Size: 8 MB
- Variables: temp_1968 = temperature (units of C) t_1968 = time (Matlab datenum format)
SBE56_1968_201609_CH1.mat
- Size: 16 MB
- Variables: temp1968 = temperature (units of C) t1968 = time (Matlab datenum format)
SBE1967_PalmyraCH1_Nov2017.mat
- Size: 29.9 MB
- Variables: temp = temperature (units of C) time = time (Matlab datenum format)
FR9
SBE05601859_PalmyraFR9_Mar2016.mat
- Size: 14.6 MB
- Variables: temp_1859 = temperature (units of C) t_1859 = time (Matlab datenum format)
SBE56_1967_201609_PalmyraFR9_Sep2016.mat
- Size: 14.4 MB
- Variables: temp1967 = temperature (units of C) t1967 = time (Matlab datenum format)
SBE1859_PalmyraFR9_Nov2017.mat
- Size: 26.2 MB
- Variables: temp = temperature (units of C) time = time (Matlab datenum format)
Temperature, current data: Aquadopp ADCP
RT4
PalmyraAQD5309_RT4_201409-201503.mat
- Size: 1.4 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format) <br>
PalmyraAQD1848_RT4_201503-201508.mat
- Size: 1.5 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format)
FR7
PalmyraAQD5327_FR7_201409_201503.mat
- Size: 1.6 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format)
PalmyraAQD2839_FR7_Aug2015.mat
- Size: 1.4 MB
- Variables: p2839 = ambient pressure at location of instrument (units of dbar) temp2839 = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time2839 = time (Matlab datenum format)
FR5
PalmyraAQD5308_FR5_201409-201503.mat
- Size: 1.4 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format)
PalmyraAQD2841_FR5_Aug2015.mat
- Size: 1.3 MB
- Variables: p2841 = ambient pressure at location of instrument (units of dbar) temp2841 = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time2841 = time (Matlab datenum format)
CH1
PalmyraAQD5264_CH1_201409_201503.mat
- Size: 1.4 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format)
FR9
PalmyraAQD2914_FR9_201409_201503.mat
- Size: 1.3 MB
- Variables: battery = battery voltage heading = angle of instrument relative to defined zero point pressure = ambient pressure at location of instrument (units of dbar) temperature = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time = time (Matlab datenum format)
PalmyraAQD2834_FR9_Aug2015.mat
- Size: 1.4 MB
- Variables: p2841 = ambient pressure at location of instrument (units of dbar) temp2841 = local temperature (units of C) v1 = zonal current velocity (units of m/s) v2 = meridional current velocity (units of m/s) v3 = vertical current velocity (units of m/s) time2841 = time (Matlab datenum format)
Water sample data (salinity and seawater delta-18O)
PALMYRA_SALINITY_2014-2016.mat
- Size: 2 KB Variables: DATE = calendar date (Matlab datetime format) SALINITYPSU = salinity (units of psu) SITE = string abbreviation for site at which sample was collected (see table above for locations)
PALMYRA_D18OSW_2014-2016.mat
- Size: 3 KB Variables: DATE = calendar date (Matlab datetime format) SITE = string abbreviation for site at which sample was collected (see table above for locations) d18Osw = delta-18O value for the seawater sample (units of per mil relative to VSMOW) std_d18Osw = standard deviation associated with measurement uncertainty on d18Osw (units of per mil relative to VSMOW)
Precipitation amount and precipitation delta-18O data
PALMYRA_RAINFALL_2014-2016_WithIso_updatedfeb2018.mat
- Size: 7 KB Variables: Date = calendar date (Matlab datetime format) Precip <br>
Methods
Physical oceanographic measurements were performed via regular (1 per 6 months) deployments at 5 different sites off the coast of Palmyra. At each site, Seabird SBE37s were installed for the measurement of temperature and salinity. However, biofouling and other instrument failures interfered with the continuous collection of salinity data. In deployments 2015 and later, Seabird SBE56s were deployed at all sites for additional temperature measurements. Aquadopp current meters were deployed at all locations as well, in addition to temperature, these instruments collected data on 3D current velocities at 5m vertical resolution. Aquadopp current data was averaged over the 25m closest to the bottom at each site to minimize issues from near-surface scattering. Daily averages were computed for each velocity component, and data trimmed to eliminate artifacts associated with deployment/retrieval. In situ data were inspected visually, and discontinuities related to noise, deployment/retrieval, and instrument failure manually removed. In the case of salinity, discontinuities related to biofouling were identified through visual inspection, and subjected to a requirement of a temporal derivative less than 0.5 ppt/sample. In ambiguous cases, matching with TAO buoy or satellite information was performed to identify corrupted portions of the time series.
Collection of rain and seawater samples was carried out by the science team during deployment visits, and by Nature Conservancy staff between visits. Seawater samples were collected at the locations of each instrument during deployment and retrieval, using manual bucket sampling from the surface ocean extending as deep as possible (roughly 1-2 feet) to minimize influences from the `skin' layer. Since boat visits to each site were not possible on a continuous basis, weekly sampling by the TNC staff was performed from shore. This was done in three locations: within the main atoll lagoon (the Ripple Wharf, or RW1), on the northern shore of the atoll directly south of the FR7 site (`FR7 Shore'), and on the northwestern shore of the atoll (`Strawn1'). For the two shore locations, samples were obtained by wading out past the breakers to ensure open ocean conditions were being sampled, and again manually retrieving waters from the upper 1-2 feet. Rainwater sampling was performed using a rain collector installed at the existing Palmyra weather station. Rain amounts were recorded every day, and samples collected daily on days where precipitation occurred. After collection, the seawater sample bottles were sealed using Parafilm and rainwater sealed by crimping the top of the bottle to prevent post-collection fractionation, and samples were stored in atoll-based climate-controlled laboratory facilities until shipment to Georgia Tech for processing.
Usage notes
The physical oceanographic and precipitation deployment data is stored in Matlab .mat file format, which is readable in Matlab, R, or Python.