Comparison of aerosol eddy covariance fluxes and chamber-simulated sea spray emissions from the Baltic Sea

Julika Zinke, E. Douglas Nilsson, Piotr Markuszewski, Paul Zieger, E. Monica Mårtensson, Anna Rutgersson, Erik Nilsson, and Matthew E. Salter

The dataset comprises aerosol eddy covariance (EC) flux data measured on Östergarnsholm island in the Baltic Sea as well as data from ship-based laboratory experiments using a plunging jet sea spray simulation chamber filled with local seawater which where conducted in the proximity of Östergarnsholm island in May and August 2021.

The combination of EC flux measurements and the chamber experiments allowed to scale the chamber generated sea spray to realistic emission fluxes and to derive a wind speed-dependent and wave state-dependent sea spray aerosol parameterization for particles with dry diameters between 0.015 and 10 µm for low-salinity waters such as the Baltic Sea.

Citation

Julika Zinke, E. Douglas Nilsson, Piotr Markuszewski, Paul Zieger, E. Monica Mårtensson, Anna Rutgersson, Erik Nilsson, and Matthew E. Salter (2023) Comparison of aerosol eddy covariance fluxes and chamber-simulated sea spray emissions from the Baltic Sea. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/zinke-2023-baltic-emissions-1

References

Zinke et al. (accepted): Sea spray emissions from the Baltic Sea: Comparison of aerosol eddy covariance fluxes and chamber-simulated sea spray emissions, will be published in Atmospheric Chemistry and Physics

Data description

Aerosol number and size data from chamber experiments

The number and size of sea spray aerosols generated in the sea spray simulation chamber was measured with a differential mobility particle sizer (DMPS) that measured particles with electrical mobility diameters between 0.015 and 0.906 µm distributed over 37 size bins, while a white-light optical particle size spectrometer (WELAS) measured particles with optical diameters between 0.150 and 10 µm distributed over 59 bins. The data from both instruments was combined at 0.35 µm and re-sampled to the same time points as the EC flux data.

chamber_experiments.xlsx

The resulting aerosol size distribution across 74 size bins for each time point is provided as a spreadsheet containg the following two sheets.

1. Mean values The first sheet contains the mean concentrations [cm³] per size bin for each campaign and plunging jet flowrate
2. Time resolved The second sheet contains the time resolved data per size bin [cm³]. Nan values mark times times when the ships were not located next to the flux tower pollution events or during pollution events.

seawater_properties.xlsx

Complimentary data on the seawater properties was measured by a wave rider buoy located in the proximity of Östergarnsholm island and sensors that were installed in the chamber experiments. A compilation of this data is provided as a spreadsheet with 8 columns.

1. Local time (UTC+2) matching the time resolution of the EC measurements
2. Salinity [g/kg]
3. Seawater temperature [°C]
4. Wave height [m]
5. Wave age [unitless]
6. Wave Reynolds number [unitless]
7. Dissolved oxygen concentration [µM/L]
8. Chlorophyll-a concentration [reference fluorescence units, RFU]

open_sea_sector.xlsx

In the corresponding publication we only used data from the wind sector that was found to be representative of open sea conditions (between 80 – 220 degrees). The provided spreadsheet contains two columns.

1. Local time (UTC+2)
2. The second column indicates whether a data point can be considered open sea or not, where 1 means that the data point can be considered as open sea and a 0 indicates that this is not the case.

Aerosol eddy covariance data

The aerosol eddy covariance (EC) data consists of three fixed-width ascii data files listed below and a README.txt file with a detailed data description.

1. size_parameters.txt contains the lower size cut, mean diameters and logarithmized bin width of the OPC in µm
2. time_serie.txt contains time, micro-meteorological parameters, estimated flux losses, and integrated flux estimates at a time resolution of 30 minutes
3. size_by_time.txt contains flux estimates and loss estimates for each of the 15 size bins and time points

The EC fluxes were measured with an optical particle counter (OPC), Licor and ultrasonic anemometer installed on a 10 m high tower on Östergarnsholm island. The data from the campaigns in May and August 2021 were combined in these files.

time_serie.txt

Column description

time units

1. year
2. month
3. day of month
4. local time in hours [loctime]
5. local time in hours with decimals
6. decimal day of the year [dd]

additional wind parameters

7. rotated horizontal mean wind speed (m/s) [Umean]
8. absolute horizontal wind direction (north=zero degrees) [WD]

additional thermodynamic parameters

9. Potential temperature (K) [T_pot]
10. Potential virtual temperature (K) [T_pot_vir]
11. Specific humidity (kg water/kg air), calculated from Licor water concentration and temperature. [dq_H2O]
12. Partial water vapor pressure (e) (Pa), calculated from Licor water concentration and temperature.[e]
13. Saturated partial water vapor pressure (e_s) (Pa) [e_s]
14. Saturation vapor ratio (S) (non-dimensional) [S]
15. Relative humidity (RH) (%), calculated from Licor water vapor concentration and temperature [RH]
16. actual mean air temperature calculated from the acoustic temperature measured by the ultrasonic anemometer, following Kaimal and Gaynor (1991) (currently empty, use acoustic temperature from original file) [Tmean_corr]
17. standard deviation of the actual air temperature (K), calculated from Sonic and Licor [Tstd_corr]
18. actual sensible heat flux H calculated iteratively from the buoyancy flux, the covariance between acoustic temperature and vertical wind following Kaimal and Gaynor (1991) and Schotanus et al. (1983). Currently empty. Use meanwhile the buoyancy flux from the original EC flux files as if it is true sensible heat flux (small error in most cases). [H_corr]

additional turbulent parameters

19. Turbulent sensible vertical heat flux (W/m²) [wT]
20. Turbulent latent vertical heat flux LE (L=lambda) (W/m²) [LEd]
21. Total turbulent kinetic energy (TKE) (m²/S²) [TKE]
22. Surface roughness (z0) (m), solved numerical from EC-data and the logarithmic wind law. Currently empty. [z0]
23. Surface roughness (z0) (m), approximated with the Charnock z0 parameterisation for oceans. [z0_Charnock]
24. Surface drag coefficient (CD0) (non-dimension) [CD0]
25. Aerodynamic surface layer resistance (ra) (m/s) [r_a]

gas flux corrections

26. Water fraction of the Webb correction for H₂O. See Webb et al. (1980).[ FS_Wcorr_H2O_water]
27. Heat fraction of the Webb correction for H₂O. [FS_Wcorr_H2O_heat]
28. Water fraction of the Webb correction for CO₂. [FS_Wcorr_CO2_water]
29. Heat fraction of the Webb correction for CO₂. [FS_Wcorr_CO2_heat]
30. Corrected vertical turbulent H₂O fluxes. [FdH2O]
31. Corrected vertical turbulent CO₂ fluxes. [FdCO2]

Random aerosol flux errors

32. Discrete counting error for the CPC. (10⁶ /m²/s) [err_disc_CPC]
33. Discrete counting error for the OPC. (10⁶ /m²/s) [err_disc_OPC]

Systematic aerosol flux or concentration errors/corrections

34. Flux losses due to particle losses in the sampling line for the OPC, for the total OPC size range aerosol flux. (10⁶ /m²/s) [Fopc_part_tube_loss]
35. Error in particle mean concentration due to particle losses in the sampling line for the OPC, for the total OPC size range concentration. (1/cm³) [Nopcmean_part_tube_loss]
36. Error in particle concentration standard deviation due to particle losses in the sampling line for the OPC, for the total OPC size range concentration. (1/cm³) [Nopcstd_part_tube_loss]
37. Aerosol flux losses due to signal damping in the sampling line, for the CPC. (10⁶ /m²/s) [Fcpc_tube_damp]
38. Aerosol flux losses due to signal damping in the sampling line, for the OPC. (10⁶ /m²/s) [Fopc_tube_damp]
39. Aerosol flux losses due limited response time of the CPC. (10⁶ /m²/s) [Fcpc_limit_sensor]
40. Aerosol flux losses due limited response time of the OPC. (10⁶ /m²/s) [Fopc_limit_sensor]
41. Water fraction of the Webb correction for OPC aerosol flux. Failed corrections marked with NaN. (10⁶ /m²/s) [FS_Wcorr_opc_water]
42. Heat fraction of the Webb correction for OPC aerosol flux. Failed corrections marked with NaN. (10⁶ /m²/s) (for the Östergarnsholm flux system this is zero, or absent (NaN) by definition) [FS_Wcorr_opc_heat]
43. Uncorrected CPC fluxes. (10⁶ /m²/s) [Fcpc_uncorr]
44. Uncorrected OPC fluxes. (10⁶ /m²/s) [Fopc_uncorr]
45. Finally corrected CPC fluxes. (10⁶ /m²/s) [Fcpc]
46. Finally corrected OPC fluxes, for the sub-set where all corrections worked. For half hours with failed Webb and/or Kowalski corrections we have entered NaN. (10⁶ /m²/s) [Fopc]
47. Empty

empirically modelled aerosol deposition fluxes, based on observed size distributions, u*, z/L, z0

48. Total aerosol dry deposition flux for the OPC. (10⁶ /m²/s) [Fdep_mod_sum]

estimated aerosol emissions

49. Total aerosol emission flux for the entire OPC size range. (10⁶ /m²/s) Data where all corrections worked. For half hours where some corrections didn't work, we have entered NaN. [E_opc_mod_sum]
50. Empty

size_parameters.txt

Line description

1. Lower OPC size bin cut. The uppermost cut was 2.5 micrometer diameter. (micrometers)
2. Geometric mean diameter for each size bin (Dg) (micrometers)
3. Logarithmized (10-base) size bin width (dlogD) (non-dimensional)

size_by_time.txt

Column description

1. Decimal day of the year (days).

Line description

each of them x15

• 2-16 Size bins 1-15 of the OPC for one parameter etc.

random errors

• 2-16 (15 bins). Discrete counting error for the OPC for each size bin. (10⁶ /m²/s)

systematic errors/corrections

particle losses in tube

• 17-31 (15 bins) Flux losses due to particle losses in the sampling line for the OPC, for each OPC size bin. (10⁶ /m²/s)
• 32-46 (15 bins) Error in particle mean concentration due to particle losses in the sampling line for the OPC, for each OPC size bin. (1/cm³)
• 47-61 (15 bins) Error in particle concentration standard deviation due to particle losses in the sampling line for the OPC, for each OPC size bin. (1/cm³)

signal losses

• 62-76 (15 bins) Aerosol flux losses due to signal damping in the sampling line, for each OPC size bin. (10⁶ /m²/s)
• 77-91 (15 bins) Aerosol flux losses due limited response time of the OPC, for each size bin. (10⁶ /m²/s)

Webb correction

• 92-106 (15 bins) Heat fraction of the Webb correction for OPC aerosol flux, for each size bin. (10⁶ /m²/s)
• 107-121 (15 bins) Water fraction of the Webb correction for OPC aerosol flux, for each size bin. (10⁶ /m²/s)

OPC by dFopcDlogD

• 122-136 (15 bins) dFopcDlogD completely corrected. (10⁶ /m²/s)
• 137-151 (15 bins) dFopcDlogD uncorrected (10⁶ /m²/s)

OPC bin by bin

• 152-166 (15 bins) Completely corrected OPC flux bin by bin (F) (10⁶ /m²/s)
• 167-181 (15 bins) Completely corrected OPC flux bin by bin (F)(10⁶ /m²/s)

modelled aerosol dry deposition

• 182-196 (15 bins) Quasi-laminar sub-layer resistance, total, for each size bin (s/m). From Schack et al. (1984)
• 197-211 (15 bins) Quasi-laminar sub-layer resistance, Brownian diffusion, for each size bin (s/m). From Schack et al. (1984)
• 212-226 (15 bins) Quasi-laminar sub-layer resistance, Impaction, for each size bin (s/m). From Schack et al. (1984)
• 227-241 (15 bins) Gravitational settling velocity, for each size bin (m/s).
• 242-256 (15 bins) Aerosol dry deposition velocity, for each size bin (m/s), from Schack et al. (1984).
• 257-271 (15 bins) Modelled dry deposition aerosol flux, for each size bin of the OPC. (10⁶ /m²/s)
• 272-286 (15 bins) Modelled dry deposition aerosol flux, for each size bin of the OPC per size increment (dF/dlogD). (10⁶ /m²/s)

estimated aerosol emission fluxes

• 287-301 (15 bins) Estimated aerosol emission fluxes for the OPC size range, for each size bin, using all corrections, when these worked. (10⁶ /m²/s)
• 302-316 (15 bins) Estimated aerosol emission fluxes for the OPC size range, for each size bin, using all corrections, including "negative emission" fluxes (only for statistical analysis). (10⁶ /m²/s)
• 317-331 (15 bins) Estimated aerosol emission fluxes for the OPC size range, for each size bin, using all corrections, when these worked. Per size increment (dE/dlogD). (10⁶ /m²/s)
• 332-346 (15 bins) Estimated aerosol emission fluxes for the OPC size range, for each size bin, using all corrections, including "negative emission" fluxes (only for statistical analysis). Per size increment (dE/dlogD). (10⁶ /m²/s)