DOI: 10.25349/d95338
title: Local physical oceanographic and oxygen isotopic observations at Palmyra Atoll of the 2014-15 and 2015-16 El Nino events

description: 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.
description: 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.
description: The physical oceanographic and precipitation deployment data is
 stored in Matlab .mat file format, which is readable in Matlab, R, or
 Python.
description: # 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](https://datadryad.org/stash/dataset/doi:10.7272/Q6XK8CS6)) 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-<sup>18</sup>O data PALMYRA\_RAINFALL\_2014-2016\_WithIso\_updatedfeb2018.mat * Size: 7 KB Variables: Date = calendar date (Matlab datetime format) Precip <br>