Light absorbing aerosol along with air mass history measured at the Zeppelin observatory in Svalbard

Dominic Heslin-Rees, Peter Tunved, Johan Ström, Roxana Cremer, Paul Zieger, Ilona Riipinen, Annica Ekman, Konstantinos Eleftheriadis, and Radovan Krejci

The dataset includes a harmonised 22-year long time series (2002 – 2023) of light-absorbing aerosol atmospheric particles. In support of the harmonised dataset there is data on the scattering coefficients and air mass back trajectory history.

Light-absorbing atmospheric particles (e.g. black carbon, BC) exert a warming effect on the Arctic climate and this dataset contains the tracking of the light-absorbing atmospheric particles in the arctic atmosphere. The data is part of the ongoing research conducted by the Stockholm University Research Station situated at the Zeppelin Mountain in Svalbard.

The light-absorbing coefficient measurements are composed of a series of different instruments i.e. a “manual” Particle Soot Absorption Photometer (PSAP), an “automatic” PSAP and a Multi Angle Absorption Photometer (MAAP). The instruments are compared with one another and correction factors are applied to the data sets in reference to the MAAP measurements.

Citation

Dominic Heslin-Rees, Peter Tunved, Johan Ström, Roxana Cremer, Paul Zieger, Ilona Riipinen, Annica Ekman, Konstantinos Eleftheriadis, and Radovan Krejci (2024) Light absorbing aerosol along with air mass history measured at the Zeppelin observatory in Svalbard. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/zeppelin-heslin-rees-2024-light-scattering-1

References

Heslin-Rees, D., Tunved, P., Ström, J., Cremer, R., Zieger, P., Riipinen, I., Ekman, A., Eleftheriadis, K., & Krejci, R. (2023). Increase in precipitation scavenging contributes to long-term reductions of black carbon in the Arctic. https://doi.org/10.5194/egusphere-2023-940

Data description

This dataset consists of the following files, and the scripts can be found on Zenodo under https://doi.org/10.5281/zenodo.10456676.

1. oldpsap_newpsap_maap.dat: csv file containing two columns.

   1. Date and time, measurements start in 2002 and continued to 2023.
   2. abs637 Light absorption coefficient measured at 637 nm based on measurements taken by PSAPs and a MAAP.

2. df_scat_TSI_ecotech_Mie_noLOD.dat: csv file containing 25 columns.

   1. Date and time
   2. Various columns related to the light scattering at different wavelengths (i.e. 450, 530, 550, 635, 637, 700). Light scattering coefficient data is provided from the Ecotech and TSI Nephelometer at Zeppelin Observatory. Includes the Absorption Ångström Exponent (AE), pressure, temperature and relative humidity, whether the data is recovered via a cleaning method ('cleaned_data') and if it is produced from Mie-calculations (Mie).

3. era5_GDAS_2002_2023.dat: csv file containing 4 columns.

   1. arrival_time Date and time
   2. fraction_241 fraction of back trajectories composing the accumulation values (out of a possible 241-hour-long back trajectory)
   3. tp_era5 ERA5 reanalysis data collocated to the endpoints of the back trajectories
   4. RAINFALL Accumulated Precipitation along 10-day back trajectories (ATP) is also provided. The data provides accumulated rainfall rates along the back trajectories for both the GDAS met fields (HYSPLIT output).

4. fire_count.dat: csv file containing 2 columns.

   1. arrival_time Date and time
   2. fire_count The accumulated number of active forest fires detected by MODIS is added. This data file provides the total number of fires along back trajectories that are active within a 1x1 grid and within the mixed-layer of the passing back trajectory. Only the endpoints of the back trajectories which pass within the mixed-layer are used.

5. GFED.dat: csv file containing 2 columns.

   1. arrival_time Date and time
   2. BC_GFED The accumulated black carbon emissions from forest fires are also added. The forest fire emissions come from the Global Fire Emission Database (GFED). All back trajectories arrive at Zeppelin Observatory.

6. ECLIPSE.dat: csv file containing 2 columns.

   1. arrival_time Date and time
   2. BC_emis_all The accumulated black carbon emissions from emission inventory. The BC emissions come from the ECLIPSE V6b global emission inventories. All back trajectories arrive at Zeppelin Observatory.

7. CWT_arrays folder: txt files containing the various concentration-weighted trajectory (CWT) arrays. They provide CWT values based on the light-absorbing coefficients measured at ZEP, and the HYSPLIT output. There is an array for each year. In the Jupyter notebooks folder is called 'arrays'.

8. trend_array_2002_2022_CWT.txt: The trend array is uploaded which uses CWT arrays from 2002 to 2022, and a Theil-Sen slope estimator (TS) is used to calculate the trend per grid box. The trend array for the eclipse emission inventories is included in the file trend_array_eclipse.txt. In the Jupyter notebooks the files are called 'trend_array_2002_2022' and 'trend_array'.

9. Cluster_residence_times folder: txt files containing arrays with the results of a 5 k-means clustering of the back trajectories.

10. mean_trajs_clusters folder: containing 5 csv files with the results of a 5 k-means clustering of the back trajectories. The arrays representing the air masses of the respective clusters or transportation pathways, include the residence times (i.e. time spent over grid cells), the mean path and the timeseries for the clusters. In the Jupyter notebooks the folder for the residence times is called 'full_layer'.

    1. df_mean_traj_cluster_5.dat with 3 columns:
       • lat Latitude
       • lon Longitude
       • alt Altitude

11. In folder trends_calculated_abs: Calculated trends in absorption, for the various bins and fractions of data e.g. pw_trends_100percentage_1bin_threshold10.txt. In the Jupyter notebooks the folder is called 'trends_cal_abs'.