Vertical in situ measurements of aerosols and meteorological variables from expedition ARTofMELT, Arctic Ocean, 2023

Roman Pohorsky, Radiance Calmer, Ian Brooks, Heather Guy, Nicolas Fauré, Lea Haberstock, Jessie Creamean, Camille Mavis, Julia Schmale

A Helikite was deployed from the Oden icebreaker during the ArtOfMelt expedition from 16 May to 10 June 2023 over sea ice in the Fram strait. The meteorological and aerosol measurements aimed to study the transition to summer conditions in the High Arctic when the onset of sea ice melt occurs.

The Helikite flights reached a maximum altitude of 645 m a.m.s.l. (above mean sea level).

The variables introduced in the dataset originated from temperature and relative humidity sensors, saved with the Flight Computer (FC) data acquisition system, along with pressure. Wind speed and direction were obtained with a SmartTether Weather Sonde. Aerosol number size distributions ranging from 8 nm to 280 nm (electrical mobility) were measured with a Miniaturized Scanning Electrical Mobility Sizer (mSEMS). A Portable Optical Particle Spectrometer (POPS) provided the aerosol number size distribution from 186 nm to 3370 nm (Optical diameter). A Single-channel tricolor absorption photometer (STAP) measured the aerosol light absorption at 450, 525, and 624 nm.

AtmosphereObservationsArcticArctic OceanARTofMELTARTofMELT 2023 expeditionIcebreaker OdenHelikiteTethered-balloonAerosol vertical profileMoMuCAMSCloud

Name

Version

Citation

References

Pohorsky R, Baccarini A, Tolu J, Winkel LHE, Schmale J (2024) Modular Multiplatform Compatible Air Measurement System (MoMuCAMS): a new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments, Atmos Meas Tech 17:731–754 https://doi.org/10.5194/amt-17-731-2024

Schmale J, Pohorsky R, Calmer R, Alden J, Temel Y, Lonardi M, Favre L, et al. (in prep) Vertical Observations of aerosols properties in the Arctic, Antarctic, and Alpine atmospheric boundary layer with a tethered balloon, Earth System Science Data (in prep).

Data description

The data are provided in three csv files.

ARTofMELT_helikite_data_Lv2.csv Level 2 data of all Helikite flights

Information on the measurements and data processing provided in the following variables.

• flight_nr flight number from 1 to 23
• DateTime date and time of measurement in UTC (yyyy-mm-dd HH:MM:SS)
• Altitude altitude in meters above the sea calculated using the hypsometric equation (m a.s.l).
• Lat latitude position in decimal degrees.
• Long longitude position in decimal degrees.
• Pressure barometric pressure (hPa).
• Temperature air temperature in degree Celsius (°C).
• Temperature_corr air temperature in degrees Celsius (°C) corrected for the ship’s effect at lower altitude.
• RH relative humidity with respect to water (%).
• WindSpeed wind speed (m/s).
• WindDir wind direction (degree).
• POPS_total_N total particle number concentration between 186 and 3370 nm from POPS (cm⁻³).
• mSEMS_total_N total particle number concentration between 8 and 280 nm from mSEMS (cm⁻³).
• STAP_sigmar_smth aerosol light absorption at 624 nm (mm⁻¹)
• STAP_sigmag_smth aerosol light absorption at 525 nm (mm⁻¹).
• STAP_sigmab_smth aerosol light absorption at 450 nm (mm⁻¹).
• POPS_b3 to POPS_b15 normalized particle concentrations for each bin (dNdlog/Dp) in cm⁻³.
• mSEMS_Bin_Conc1 to mSEMS_Bin_Conc40 normalized particle concentrations for each bin (dNdlog/Dp), in cm⁻³.
• flag_temp this flag indicates heights where the ship heat effect influences the measured temperature and where the variable Temperature_corr differs from Temperature. A 1 indicates the temperature is affected by the ship, a 0 indicates it is not.
• flag_pollution flag for local ship pollution. 1 indicates pollution.
• flag_hovering flag for when Helikite was hovering at the same altitude for more than 2 min period. 0 denotes moving, 1 denotes hovering.
• flag_cloud flag for when helikite was measuring in cloud. 0 denotes not in cloud, 1 denotes in cloud.
• campaign campaign name (ArtOfMelt).

mSEMS_bin_diameters_AOM.csv Bin limits and midpoint diameters of the mSEMS

Variables

• Bin.number
• midpoint.diameter
• Lower.limit
• Upper.limit

POPS_bin_diameters.csv Bin limits and midpoint diameters of the POPS

Variables

• lower diameter (nm)
• midpoint diameter (nm)
• upper diameter (nm)
• dlogDP

Comments

Data processing

Raw data

Files generated from individual instruments were considered raw data. Nonetheless, two instrument files, from the STAP and the mSEMS, required additional processing after flight. The manufacturer provided the processing routines. The STAP processing routine converted raw intensity in the different channels to absorption coefficient with the filter area correction and the necessary adjustments. Regarding the mSEMS data, an inversion routine is applied to the row particle counts to calculate the particle number size distributions from the measured electrical mobility distributions.

Level 0

All the instrument files are recorded at 1-second resolution (raw data). Only the mSEMS scans obtained from the inversion routine provided by the manufacturer are at a 2min40 resolution. All the files are time synchronized using the pressure measurements from individual instruments by cross-correlation. This data processing step generates a time-synchronized file including all the measurements and corresponds to Level 0.

Level 1

Level 1 addresses the data quality control and the necessary corrections to apply to some variables. The following methodology is used to quality control temperature, relative humidity, pressure, wind speed, and direction:

1. Remove spurious data with defined thresholds
2. Apply a despiking function based on an exponentially weighted moving average
3. Visual inspection For the POPS measurements, the bin counts are divided by the mean flow rate over the flight time. Bins 0 to 2 (midpoint diameters 149, 162, and 178 nm) are disregarded due to unrealistically higher counts generated by electrical noise (Pohorsky et al 2024). The total number concentration from 186 to 3370 nm is calculated as the sum of bins 3 to 15. The dataset provides the normalized number concentration per bin corresponding to dN/dlogDp. The mSEMS provides the aerosol number size distribution from 8 to 280 nm with 40 bins. The bin counts are already normalized as dN/dlogDp from the manufacturer’s processing. The STAP absorptions are obtained from the manufacturer’s routine. Values below 0 are replaced with NaN during the quality control step. It should be noticed that STAP measurements for the ArtOfMelt field deployment are usually below the detection limit of 0.2 mm⁻¹. The Standard Temperature and Pressure (STP) correction is applied to the POPS, the mSEMS, and the STAP measurements.

Level 2

Flags are added to the dataset to facilitate the interpretation of the data. As the ship’s platform was generally warmer than the surrounding ice, it created a local heat island effect which affected the vertical temperature measurements. The flag flag_temp indicates when the measured temperature is affected by the heat island by taking the value 1. When the measurements were conducted in fog/cloud, the flag_cloud values were 1. Otherwise, flag_cloud values are 0 for the other flights representing no-cloud flight conditions. The flag flag_hovering is 0 for the ascent/descent section of the flights, then 1 for the hovering periods. Hovering steps are defined as the Helikite remained at the same altitude for more than 2 minutes. The flag flag_pollution primarily represents aerosol data points affected by the local pollution from the ship’s exhaust. The local pollution is concentrated close to the surface (flag =1). At the final level, time-synchronized, quality-controlled and corrected data are averaged at 10 seconds resolution.

The expedition

Data were collected during the ARTofMELT 2023 expedition on board the Swedish icebreaker Oden, which was organized by the Swedish Polar Research Secretariat from 8 May through 14 June, 2023.

Data creators' roles

• Roman Pohorsky: Principal instrument and Helikite operator and data curator
• Julia Schmale: On shore PI. She holds the Ingvar Kamprad Chair for Extreme Environments Research sponsored by Ferring Pharmaceuticals.
• Radiance Calmer: Data processing of level 0
• Ian Brooks: Helikite operator in the field
• Heather Guy: Helikite operator in the field
• Nicolas Fauré: Helikite operator in the field
• Lea Haberstock: Helikite operator in the field
• Jessie Creamean: Onboard working group PI
• Camille Mavis: Technical assistance in the field

Equipment

• Helikite: 45 m3 Desert Star, Allsopp Helikites, UK
• Relative Humidity Sensors: SHT85, Sensirion
• SmartTether Weather Sonde: ST, Anasphere, Inc
• Miniaturized Scanning Electrical Mobility Sizer (mSEMS): Model 9404, Brechtel Manufacturing Inc., USA
• Portable Optical Particle Spectrometer (POPS): Handix Scientific LLC, USA
• Single-channel tricolor absorption photometer (STAP): Brechtel Manufacturing Inc., USA

Project

ARTofMELT 2023 expedition. ARTofMELT - VAERTICAL (Vertical properties of aerosols in the Arctic lower atmosphere and their impact on cloud radiative effects, SNSF Grant nr. 200021_212101)

Publisher

Bolin Centre Database

License

Open Data Commons Attribution License (ODC-By) v1.0

First name

Roman

Last name or organisation

Pohorsky

Email address

roman.pohorsky@epfl.ch

Address

Extreme Environments Research Laboratory; Ecole Polytechnique Fédérale de Lausanne

Postal code

1950

City

Sion

Country

Switzerland

GCMD science keyword

Earth science > Atmosphere > Aerosols

GCMD location

Ocean > Arctic Ocean

Dataset language

English

Begin date

2023-05-16

End date

2023-06-10

DOI

Time