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The paper presents the current status of the Maritime Aerosol Network (MAN), which has been developed as a component of the Aerosol Robotic Network (AERONET). MAN deploys Microtops handheld Sun photometers and utilizes the calibration procedure and data processing (Version 2) traceable to AERONET. A web site dedicated to the MAN activity is described. A brief historical perspective is given to aerosol optical depth (AOD) measurements over the oceans. A short summary of the existing data, collected on board ships of opportunity during the NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project is presented. Globally averaged oceanic aerosol optical depth (derived from island‐based AERONET measurements) at 500 nm is ∼0.11 and Angstrom parameter (computed within spectral range 440–870 nm) is calculated to be ∼0.6. First results from the cruises contributing to the Maritime Aerosol Network are shown. MAN ship‐based aerosol optical depth compares well to simultaneous island and near‐coastal AERONET site AOD.

We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in areas of the Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August–22 September 2013) and RV Professor Khljustin (24 July–7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34–2.14 μm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in a northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m−3, respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from the Japan Sea to the Chukchi Sea, the aerosol number concentration decreased on average from 23.7 to 2.5 cm−3, the black carbon mass concentration decreased from 150 to 50 ng m−3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at a latitude of ~ 55° N. For water basins of eight seas, we present the chemical compositions of the water-soluble aerosol fraction (ions, elements) and small gas-phase species, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75–89 %) supplied from the atmosphere to the sea surface together with gas-phase species. The deposited ions account for from 11 to 24.5 %, and trace elements account for 0.2–0.4 % of the total sum of water-soluble components. The average vertical fluxes of aerosol substance are a factor of 4–7 larger in the Japan Sea than in the water basins of Arctic seas.

The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. The MAN archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we investigate correlations between ship-borne aerosol optical depth (AOD) and near-surface wind speed, either measured (onboard or from satellite) or modeled (NCEP). According to our analysis, wind speed influences columnar aerosol optical depth, although the slope of the linear regression between AOD and wind speed is not steep (~0.004–0.005), even for strong winds over 10 m s−1. The relationships show significant scatter (correlation coefficients typically in the range 0.3–0.5); the majority of this scatter can be explained by the uncertainty on the input data. The various wind speed sources considered yield similar patterns. Results are in good agreement with the majority of previously published relationships between surface wind speed and ship-based or satellite-based AOD measurements. The basic relationships are similar for all the wind speed sources considered; however, the gradient of the relationship varies by around a factor of two depending on the wind data used.

The periodicity of synoptic-scale variations in aerosol characteristics in the atmosphere of Eurasian sector of the Arctic Ocean is analyzed on the basic of long-term measurements. Statistically significant maxima of amplitude functions in the range from 3.5 to 18 days were manifested in periodograms of the concentrations of submicron aerosol and black carbon ( V f and еВС). Cases of anomalously high еВС and V f (5% of data), associated with long-range transports of continental pollutants, were considered in more detail. It is shown that the average duration of “anomalies” in еВС and V f is few days, and the maximal duration attains 112 hours. The time intervals between “anomalies” are, on the average, 6–16 days, and the maximal intervals are from 28 to 69 days. Despite the short duration and rare occurrence of anomalous situations, they increase the average concentrations of aerosol and black carbon by 28–77%. Calculations showed that the major (79%) contributors to air pollution over the Kara and Barents Seas are made by the outflows of anthropogenic pollutants; and in the eastern sector of the Arctic Ocean, the contribution of smokes from wildfires is maximal. The effect of the products of associated gas combustion at gas-oil plants was manifested most strongly (up to 51%) in the atmosphere of Cape Baranov.

In this work, hourly averaged sun photometer data from Barentsburg and Ny-Ålesund, both located on Spitsbergen in the European Arctic, are compared. Our data set comprises the years from 2002 to 2018 with overlapping measurements from both sites during the period from 2011 to 2018. For more turbid periods (aerosol optical depth, AOD, τ0.5>0.1), we found that Barentsburg is typically more polluted than Ny-Ålesund, especially in the shortwave spectrum. However, the diurnal variation in the AOD is highly correlated. Next, τ was divided into a fine and coarse mode. It was found that the fine-mode aerosol optical depth generally dominates and also shows a larger interannual than seasonal variation. The fine-mode optical depth is in fact largest in spring during the Arctic haze period. Overall the aerosol optical depth seems to decrease (at 500 nm the fine-mode optical depth decreased by 0.016 over 10 years), although this is hardly statistically significant.

A multi-year analysis of aerosol optical depth (AOD, τ) and Ångström exponent (α) was conducted using ground-based photometer data from 15 Arctic and 11 Antarctic sites. Extending the dataset of (Tomasi et al., 2015) through December 2024, the study incorporates stellar and lunar photometric observations to fill data gaps during the polar night. Daily mean values of τ at 0.500 µm and α (0.440–0.870 µm) were used to derive monthly means and seasonal histograms. In the Arctic, persistent haze events in winter and early spring lead to peak τ values. A decreasing trend in Arctic τ suggests the impact of European emission regulations, while biomass-burning aerosols are becoming more significant. In Antarctica, τ increases from the plateau to the coast. Fine-mode aerosols dominate in summer-autumn, while coarse-mode particles are more prevalent in winter-spring. Shipborne photometer data align well with ground-based measurements, confirming the reliability of mobile observations. Trend analyses using the Mann-Kendall test and Theil-Sen regression indicate a significant negative trend in τ at Andenes (−2.43 % per year), likely driven by reduced anthropogenic emissions. Antarctic stations such as Syowa and South Pole show positive trends (+3.84 % and +3.54 % per year), though these are subject to uncertainties from data limitations and instrument changes. This work contributes to the Polar-AOD network (https://polaraod.net/, last access: 15 May 2025), enhancing the understanding of aerosol variability and long-term trends in polar regions while promoting open data access for the scientific community.

Microphysical and optical properties of aerosol were studied during a mega-fire event in summer 2012 over Siberia using ground-based measurements of spectral solarradiation at the AERONET site in Tomsk and satellite observations. The data were analyzed using multi-year (2003-2013) measurements of aerosol characteristics under back-ground conditions and for less intense fires, differing in burning biomass type, stage of fire, remoteness from observation site, etc. (ordinary smoke). In June-August 2012, the average aerosol optical depth (AOD, 500 nm) had been 0.95+/-0.86, about a factor of 6 larger than background values (0.16+/-0.08), and a factor of 2.5 larger than in ordinary smoke. The AOD values were extremely high on 24-28 July and reached 3-5. A comparison with satellite observations showed that ground-based measurements in the region of Tomsk not only reflect the local AOD features, but are also characteristic for the territory of Western Siberia as a whole. Single scattering albedo (SSA, 440 nm) in this period ranged from 0.91 to 0.99 with an average of approx. 0.96 in the entire wavelength range of 440-1020 nm. The increase in absorptance of aerosol particles (SSA(440 nm)=0.92) and decrease in SSA with wavelength observed in ordinary smoke agree with the data from multi-year observations in analogous situations in the boreal zone of USA and Canada. Volume aerosol size distribution in extreme and ordinary smoke had a bimodal character with significant prevalence of fine-mode particles, but in summer 2012 the mean median radius and the width of the fine-mode distribution somewhat increased. In contrast to data from multi-year observations, in summer 2012 an increase in the volume concentration and median radius of the coarse mode was observed with growing AOD.

The results of studies into the aerosol optical depth (AOD) for the atmosphere in the Middle Urals in the spectrum range of 0.34–1.02 μm for 2004–2010 is presented. The interannual, annual, seasonal, and daily variations in the AOD are analyzed. The major statistical characteristics of the AOD, the parameters of the probability density function of distributions over different wave lengths, and the parameters of Angstrom’s formula for the different seasons are calculated. The monitoring stations in the Russian segment of the AERONET network are ranked with respect to the AOD value. A shift from March to May in the spring maximum of the AOD is revealed in comparison with the results of the actinometric observations for the period of 1960–1986. A qualitative assessment is given to the influence of forest and peat fires in the region on the AOD. A classification of the states of aerosol haze in the atmosphere according to the AOD values is proposed.

The interest in aerosol studies in the Arctic stems from the large dynamics of the climate processes and active economical development of this region. The number of polar stations, available at present, is insufficient to determine the aerosol spatial distribution over the territory of the Arctic Ocean (AO). In this paper, the long-term studies in the Eurasian sector of the Arctic Ocean (AO) (19 ship-based expeditions in 2007–2023) are used to statistically generalize the volume concentrations of fine and coarse aerosol ( V f and V с ) in the near-water layer and the aerosol optical depth (AOD) of the atmosphere. The average AOD (0.5 μm) was 0.061 with an Ångström exponent of 0.9; the average concentrations of fine and coarse aerosol were 0.35 and 2.5 μm 3 /cm 3 , respectively. The content of fine aerosol was the largest in the atmosphere over the Norwegian and Barents Seas. The spatial distribution was characterized by the decline in the concentrations in northern and eastern directions: the average V f value decreased by a factor of 1.7 (from 0.43 to 0.26 μm 3 /cm 3 ) from the Barents to Chukchi Sea. In the spatial distribution of coarse aerosol very high concentrations were in the southwestern part of the Kara Sea; the average V с was 4.18 μm 3 /cm 3 . The content of coarse aerosol were in the Kara Sea severalfold decreased in the eastern and western directions. These results can be used in planning the economical development of the Arctic region and refining climate models.

In this paper the results of investigations into atmospheric aerosol optical depth (AOD) over the Atlantic Ocean are discussed. The data were collected during five shipboard expeditions that took place between 1989 and 1996.