OVERVIEW

Dataset Title: Coastal soil temperature, resistivity, and porewater salinity: Prudhoe Bay, Alaska 2022-2024

Contact: alina.spera@whoi.edu // julia.guimond@whoi.edu File description(s):

Elevation_Salinity_Thawdepth.csv - Elevation (meters above sea level), porewater salinity (ppt), and thawdepth (cm) for 68 observations with UTM lat/long at field site near Prudhoe Bay, Alaska

GEM_A_PlottingData_Final.csv - UTM XY location, depth, resisitivity (RHO) value, and electric conductivity (EC) for A transect ElectroMagnetic Imaging (EMI) data. Each resistivity value corresponds to a depth range (from top to bottom).

GEM_B_PlottingData_Final.csv - UTM XY location, depth, resisitivity (RHO) value, and electric conductivity (EC) for B transect ElectroMagnetic Imaging (EMI) data. Each resistivity value corresponds to a depth range (from top to bottom).

ERT_TransectA_0723_final_resistivity_data.csv - Location along transect, depth, resisitivity value, and electric conductivity (EC) value for A transect (non-inundated site) for Electrical Resistivity Tomography (ERT)

ERT_TransectB_0723_final_resistivity_data.csv - Location along transect, depth, resisitivity value, and electric conductivity (EC) value for B transect (inundated site) for Electrical Resistivity Tomography (ERT)

ERT_TransectD_0723_final_resistivity_data.csv - Location along transect, depth, resisitivity value, and electric conductivity (EC) value for C transect (inundated site) for Electrical Resistivity Tomography (ERT)

ERT_TransectE_0723_final_resistivity_data.csv - Location along transect, depth, resisitivity value, and electric conductivity (EC) value for D transect (inundated site) for Electrical Resistivity Tomography (ERT)

ERT_TransectE_0723_final_resistivity_data.csv - Location along transect, depth, resisitivity value, and electric conductivity (EC) value for E transect (inundated site) for Electrical Resistivity Tomography (ERT)

Temperature_Timeseries_Final.csv - Timeseries of sediment temperature data for 3 sites (non-inundated, infrequently inundated, frequently inundated) across 6 depths (0-50 cm).

Keywords: Hydrothermal properties; ERT; Permafrost

TEMPORAL

Date start (YYYY-MM-DD): 2022-07-01

Date end (YYYY-MM-DD): 2024-09-03

SITE INFORMATION

Location: No Point, Prudhoe Bay, Alaska

Site type: Coastal tundra experiencing seawater inundation

VARIABLE INFORMATION

Variable abbreviations: Elevation_Salinity_Thawdepth: Site name or identifier = site_number; Month and Year of collection = month_year; Latitude= lat; longitude: long; Elevation above sea level = elevation_m; Thaw depth = thawdepth_cm; Porewater sampling depth = porewater_depth_cm; Porewater salinity = porewater_salinity_ppt;

Variable abbreviations: ERT: Distance along transect = distance_m; Elevation relative to NAD83 = elevation_m; Resistivity = Rho_ohm_m; Electrical Conductivity = EC_S_m

Variable abbreviations EMI: UTM_X; UTM_Y; Top depth from surface = top_depth_m; Top elevation relative to NAD83 = top_elev_m; Bottom depth from surface = bottom_depth_m; Bottom elevation relative to NAD83 = bottom_elev_m; Resistivity= RHO_ohm_m; distance along transect = distance_m; Electrical Conductivity= EC_S_m;

Variable abbreviations Timeseries_Temperature: Datetime in AKT = DateTime_AK; Site flooding frequency = Site_Flooding_Frequency; Soil depth = Depth_cm; Temperature = temperature_C; Latitude= lat; longitude: long;

No data value: NA

TIME SERIES RESULTS INFORMATION

Units type: Temperature

Units name: Degree C

Units abbreviation: C

Status: Ongoing

Sample medium: Soil

Aggregation statistic: Continuous

UTC Offset Information: 9 hours (09:00:00)

METHOD INFORMATION

Method name: Electric Resistivity Tomography

Method type: Instrument observations

Method description: Surveys were conducted using SuperString R8-IP eight-channel resistivity meter from Advance Geosciences, Inc. (AGI).

Processing information: The resultant output DD and S apparent resistivity data were merged to enhance the subsurface resolution by using AGI EarthImager™ 2D software. Inversion of measured apparent resistivity to true resistivity were conducted using RES2DINV® software.

Method name: Electromagnetic Imaging

Method type: Instrument observations

Method description: Five surveys were conducted with an Electromagnetic Induction (EMI) instrument (GEM-2, Geophex Ltd., USA) in 2023 and 2024 to estimate subsurface electrical conductivity.

Processing information: Inversions were conducted using a smooth inversion approach with 20 total layers and a total residual less than 0.5.

Method name: Temperature profiles

Method type: Instrument observations

Method description: Three 50 cm long T.rod.X (Alpha Mach, Canada) temperature probes with sensor depths at 0, 5, 10, 15, 25, 50 cm were installed.

Method name: Salinity measurements

Method type: Instrument observations

Method description: Porewater was extracted with push-point piezometer and salinity was analyzed on site with a multi-parameter sensor (Myron L).