DOI: 10.5061/dryad.1jwstqk4z
title: Data from: Wind-driven emission of marine ice nucleating particles in the Scripps Ocean-Atmosphere Research Simulator (SOARS)

description: Sea spray aerosol (SSA) represent one of the most abundant natural aerosol
 types, contributing significantly to global aerosol mass and aerosol
 optical depth, as well as to both the magnitude and uncertainty of aerosol
 radiative forcing. In addition to their direct effects, SSA can also serve
 as ice nucleating particles (INPs), which are required for the initiation
 of cloud glaciation at temperatures warmer than ~-36 °C. This study
 presents initial results from the CHaracterizing Atmosphere-Ocean
 parameters in SOARS (CHAOS) mesocosm campaign, which was conducted in the
 new Scripps Ocean-Atmosphere Research Simulator (SOARS) wind-wave channel.
 SOARS allows for isolation of individual factors, such as wave height,
 wind speed, water temperature, or biological state, and can carefully vary
 them in a controlled manner. Here, we focus on the influence of wind speed
 on the emission of SSA and INPs. In agreement with recent Southern Ocean
 measurements, online INP observations during CHAOS showed an increasing
 relationship with wind speed, whereas offline CHAOS INP measurements did
 not, which may be related to sampling inlet differences. Changes in the
 INP activated fraction, dominant INP particle morphology, and INP
 composition were seen to vary with wind. Seawater ice nucleating entity
 concentrations during CHAOS were stable over time, indicating changes in
 atmospheric INPs were driven by wind speed and wave-breaking mechanics
 rather than variations in seawater chemistry or biology. While specific
 emission mechanisms remain elusive, these observations may help explain
 some of the variability in INP concentration and composition that have
 been seen in ambient measurements.
description: # Data from: Wind-driven Emission of Marine Ice Nucleating Particles in
 the Scripps Ocean-Atmosphere Research Simulator (SOARS)
 [https://doi.org/10.5061/dryad.1jwstqk4z](https://doi.org/10.5061/dryad.1jwstqk4z) ## Overview of the campaign The measurements archived here were collected using the Scripps Ocean-Atmosphere Research Simulator (SOARS) wind-wave channel at the Scripps Institution of Oceanography during the CHaracterizing Atmosphere-Ocean parameters in SOARS (CHAOS) study. The SOARS facility allows for the production of sea spray aerosol (SSA) in a controlled environment where individual biogeochemical parameters (wind speed, water biology and chemistry, air and water temperature) can be varied. The ability to control wind speed, in particular, is an advancement over previous wave channel experiments and increases the atmospheric relevance of the measurements. Results from CHAOS represent the first measurements obtained in the SOARS channel during July-August 2022, and focused on the impact of wind speed on SSA production.  ### Datasets Processed data collected from a suite of instruments, along with metadata relevant to the CHAOS campaign as a whole, are archived here in separate .txt files (comma-delimited). The variables, units, and other details about each file are given below. All times are given in the local Pacific Daylight Time (PDT). Missing values for wind speeds in each file indicate measurements collected in the first ~15 minutes of each sampling period, prior to particle concentrations in SOARS reaching an approximate steady-state. Descriptions of each instrument, their measurement principles, and an overview of the data processing steps are outlined in the Methods section (2) of the [corresponding manuscript](https://doi.org/10.5194/egusphere-2024-2159). #### Metadata for the CHAOS campaign A list of the experimental periods from CHAOS that were used in this manuscript are given in the file: *CHAOS_fan_archive.txt*. A description of each variable in the file is given below: Start_Time (MM/DD/YY HH:mm:SS): Start time of the experimental period End_Time  (MM/DD/YY HH:mm:SS): End time of the experimental period Main_Fan_rpm (rpm): Speed of the main blower fans in SOARS Makeup_Fan_rpm (rpm): Speed of the makeup blower fans in SOARS Filter_On (unitless): 0=SOARS headspace filters are not being used, 1=SOARS headspace filters are being used to remove particles from the air stream Waves_On (unitless): 0=waves are not turned on, 1=waves are turned on Wave_Amplitude (unitless): Scaling factor for SOARS wave packet amplitude Category (unitless): "Filter"=headspace filters are being used, "Waves"= waves are turned on, "Decay"=waves were previously on but have been stopped, "Wind"=main fans are turned on but waves are off. #### Supplementary Meteorological and Oceanographic Measurements ##### SOARS Channel Continuous Measurements Basic meteorological and oceanographic parameters measured continuously within the SOARS channel are listed in *CHAOS_channel_archive.txt* and further described in the manuscript Sec. 2.1. A description of each variable in the file is given below, and any missing values are indicated by NaN. Time (MM/DD/YY HH:mm:SS): Time of the measurement HeadSpaceAirTempCTR (degrees Celsius): Air temperature in the center of the SOARS channel ChannelWaterTempCTR (degrees Celsius): Water temperature in the center of the SOARS channel PracticalSalinity (PSU): Salinity in the SOARS channel EastFanRPM (rpm): Speed of the East main blower fan in SOARS WestFanRPM (rpm): Speed of the West main blower fan in SOARS ##### Seawater Biology and Chemistry A selection of the biological and chemical measurements made on seawater collected from SOARS are given in *CHAOS_bio_archive.txt* and further described in the manuscript Sec. 2.1. A description of each variable in the file is given below, and any missing values are indicated by NaN. Time (MM/DD/YY): Date of the measurement TOC_uM (micro mole per liter): Total organic carbon concentration Chla_ugL (microgram per liter): Chlorophyll *a* concentration NO3_uM (micro mole per liter): Nitrate concentration PO4_uM (micro mole per liter): Phosphate concentration Sil_uM (micro mole per liter): Silicates concentration NO2_uM (micro mole per liter): Nitrite concentration NH4_uM (micro mole per liter): Ammonium concentration #### Online Ice Nucleating Particle Measurements Atmospheric ice nucleating particle (INP) concentrations measured with the Continuous Flow Diffusion Chamber (CFDC) are archived in *CHAOS_CFDC_archive.txt* and further described in the manuscript Sec. 2.2.1. A description of each variable in the file is given below, and any missing values are indicated by NaN. Start_Time (MM/DD/YY HH:mm:SS.sss): Start time of the sample period Stop_Time (MM/DD/YY HH:mm:SS.sss): End time of the sample period INPs_SL (number per standard liter): Number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) Upper_CI_width (number per standard liter): 90% upper confidence interval width for number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) Lower_CI_width (number per standard liter): 90% lower confidence interval width for number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) Sample_Flow_slpm (standard liters per minute): Mean sample period air flow rate in the CFDC chamber  (100 kPa, 0 degrees C) SSw (percent): Mean sample period supersaturation with respect to water in the CFDC Temp_C (degrees Celsius): Mean sample period temperature of the CFDC aerosol lamina Pressure (mb): Mean sample period pressure inside the CFDC chamber WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m #### Offline Ice Nucleating Particle Measurements ##### Sea Spray Aerosol IS Measurements Atmospheric INP concentrations from filter samples measured with the CSU Ice Spectrometer (IS) are given in *CHAOS_IS_SSA_archive.txt* and further described in the manuscript Sec. 2.2.2 and 2.2.3. A description of each variable in the file is given below, and any missing values are indicated by NaN. If blank-correction of the untreated (base) filter samples yielded INP concentrations below zero, those measurements have been removed. However, heat and peroxide treated (manuscript Sec. 2.2.3) filter samples with negative blank-corrected concentrations were retained to assist in calculation of INP composition. To allow for plotting on logarithmic axes, which is typical for this type of data, negative heat-treated concentrations were replaced by 0.00005 and negative peroxide treated concentrations with 0.000025 in the data file. The associated confidence interval widths are given as "NaN" and the samples are marked with the flag "BDL=1". SampleName (unitless): Sample ID Date (MM/DD/YY): Date of the measurement WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m Total_V_SL (standard liters): Total volume of air passed through filter (100 kPa, 0 degrees C) Treatment (unitless): "Base"= untreated sample, "Heat"= heat treated sample (95 degrees C for 20 minutes), "Peroxide"=peroxide treated sample (10% H2O2 at 95 degrees C for 20 minutes under UV-B, then H2O2 decomposed with catalase) Temp_C (degrees Celsius): Measurement temperature of IS INPs_SL (number per standard liter): Number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) Lower_CI_width (number per standard liter): 95% lower confidence interval width for number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) Upper_CI_width (number per standard liter): 95% upper confidence interval width for number of ice nucleating particles per standard liter of air (100 kPa, 0 degrees C) CI_overlap_zero (unitless): 0=measurement confidence interval does not overlap with zero, 1=measurement confidence interval does overlap with zero BDL (unitless): 0=blank-corrected INP concentration is greater than 0, 1=blank-corrected INP concentration is less than 0. The BDL and CI_overlap_zero flags are mutually exclusive. ##### Seawater IS Measurements Seawater ice nucleating entity (INE) concentrations measured with the CSU IS are given in *CHAOS_IS_SW_archive.txt* and further described in the manuscript Sec. 2.2.2. A description of each variable in the file is given below, and any missing values are indicated by NaN. If blank-correction of the samples yielded INP concentrations below zero, those measurements have been removed. Temperature spectra of seawater samples have been adjusted by +2 degrees Celsius to account for freezing point depression due to salinity. SampleName (unitless): Sample ID Date (MM/DD/YY): Date of the measurement Treatment (unitless): "Base"= untreated sample, "Heat"= heat treated sample (95 degrees C for 20 minutes), "Peroxide"=peroxide treated sample (10% H2O2 at 95 degrees C for 20 minutes under UV-B, then H2O2 decomposed with catalase) Temp_C (degrees Celsius): Measurement temperature of IS INPs_mL (number per milliliter): Number of ice nucleating particles per milliliter of seawater Lower_CI_width (number per milliliter): 95% lower confidence interval width for number of ice nucleating particles per milliliter of seawater Upper_CI_width (number per milliliter): 95% upper confidence interval width for number of ice nucleating particles per milliliter of seawater CI_overlap_zero (unitless): 0=measurement confidence interval does not overlap with zero, 1=measurement confidence interval does overlap with zero #### Single Particle Atomic Force Microscopy of INPs Ice nucleating particles collected in the CFDC were deposited onto silicon substrates and later analyzed by atomic force microscopy (AFM) to assess their physicochemical properties. The AFM data is archived in *CHAOS_AFM_archive.txt* and further described in the manuscript Sec. 2.2.4. A description of each variable in the file is given below, and any missing values are indicated by NaN. Image_name (unitless): Image file name Particle_Number (unitless): Particle sample ID in the image Morphology_Desc (unitless): Description of the particle morphology Morphology_Cat (unitless): Classification of the particle morphology into one of six categories: "rounded", "core-shell", "prism-like", "rod", "aggregate" or "irregular" Vol_Eq_Diam_nm (nanometers): Volume equivalent diameter OVF (unitless): Organic volume fraction Org_Coat_Thickness (nanometers): Thickness of organic coating, if applicable AR (unitless): Aspect ratio Probe_Location (unitless): Where the AFM probe was placed to make the measurement. Options are: "center", "edge", "shell", or "shell inclusion". VRD_RH20 (nanometers): Viscoelastic response distance at 20% RH VRD_Std_RH20 (nanometers): Standard deviation of viscoelastic response distance at 20% RH Phase_RH20 (unitless): Particle phase at 20% RH. Options are "solid", "semisolid", or "liquid". VRD_RH60 (nanometers): Viscoelastic response distance at 60% RH VRD_Std_RH60 (nanometers): Standard deviation of viscoelastic response distance at 60% RH Phase_RH60 (unitless): Particle phase at 60% RH. Options are "solid", "semisolid", or "liquid". WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m #### Aerosol Particle Distributions ##### SMPS + APS Distributions Aerosol concentrations and number size distributions were measured by multiple instruments, as described in the manuscript Sec. 2.3. Combined data from a TSI Scanning Mobility Particle Sizer (SMPS) and a TSI Aerodynamic Particle Sizer (APS) are given in *CHAOS_SMPS_APS_archive.txt*. A description of each variable in the file is given below, and any missing values are indicated by NaN. Date (MM/DD/YYYY): Date of the measurement WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m N (number per cubic centimeter): Total aerosol number concentration across all sizes n500 (number per cubic centimeter): Total aerosol number concentration for particles larger than 500 nm dry diameter SA (micrometers squared per cubic centimeter): Total aerosol surface area concentration across all sizes V (micrometers cubed per cubic centimeter): Total aerosol volume concentration across all sizes N_xxx_um (number per cubic centimeter): Aerosol number concentration in a measurement bin, normalized by the difference of the log of the bin width (dN/dlogDp). The xxx in the variable name gives the geometric mean diameter of the bin in micrometers. ##### SEMS + APS Distributions Combined data from a BMI Scanning Electrical Mobility Spectrometer (SEMS) and another TSI Aerodynamic Particle Sizer (APS) are given in *CHAOS_SEMS_APS_archive.txt*. A description of each variable in the file is given below, and any missing values are indicated by NaN. Time  (MM/DD/YY HH:mm:SS): Start time of the sample period (5 minutes) WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m N (number per cubic centimeter): Total aerosol number concentration across all sizes n500 (number per cubic centimeter): Total aerosol number concentration for particles larger than 500 nm dry diameter SA (micrometers squared per cubic centimeter): Total aerosol surface area concentration across all sizes V (micrometers cubed per cubic centimeter): Total aerosol volume concentration across all sizes N_xxx_um (number per cubic centimeter): Aerosol number concentration in a measurement bin, normalized by the difference of the log of the bin width (dN/dlogDp). The xxx in the variable name gives the geometric mean diameter of the bin in micrometers. ##### CDFC OPC Distributions Aerosol data from the CFDC Optical Particle Counter (OPC) is archived in *CHAOS_CFDC_OPC_archive.txt*. A description of each variable in the file is given below, and any missing values are indicated by NaN. OPC integrated quantities (N, n500, SA, V) have been corrected based on simultaneous SEMS+APS data, as described in Sec. 2.3 of the manuscript. Start_Time (MM/DD/YY HH:mm:SS.sss): Start time of the sample period Stop_Time (MM/DD/YY HH:mm:SS.sss): End time of the sample period WS_U10 (meters per second): Wind speed in the SOARS channel, extrapolated to 10m OPC_N (number per cubic centimeter): Total aerosol number concentration across all sizes OPC_n500 (number per cubic centimeter): Total aerosol number concentration for particles larger than 500 nm dry diameter OPC_SA (micrometers squared per cubic centimeter): Total aerosol surface area concentration across all sizes OPC_V (micrometers cubed per cubic centimeter): Total aerosol volume concentration across all sizes N_xxx_um:  (number per cubic centimeter): Aerosol number concentration in a measurement bin, normalized by the difference of the log of the bin width (dN/dlogDp). The xxx in the variable name gives the geometric mean diameter of the bin in micrometers.