Aerosol impacts: It is all a bit hazy!

Aerosols can have a range of impacts in the Arctic. Most people associate aerosols with having cooling properties. These pollutants are accountable for causing disruption to the radiative budget; reflecting light particles and preventing solar radiation reaching the surface, thus lowering temperatures (Law and Stohl, 2007).Pumping aerosols into the atmosphere has even been suggested as a mitigation method for climate change!

However their properties do not stop there... It is important to remember that many pollutants fall under this blanket of aerosols, some causing warming (black carbon) and others cooling (sulphates). 

Sources of aerosol pollutants

Arctic air is considered to be very clean, thus the assumption can be made practically all atmospheric pollutants (especially in the higher latitudes of the Arctic) have originated from sources south of the region. Local pollution sources are very limited mostly including volcanic emissions (in Alaska), industrial pollutants (mostly from northern Russia) and emissions from shipping tankers (Fisher, 2011).

An atmospheric dome forms above (the higher latitudes of) the Arctic, isolating the lower troposphere. During winter months the dome can move as far south as 40 degrees over Eurasia, thus allowing us to conclude northern Eurasia is a major source of many of the aerosol pollutants found in the Arctic. Pollutants, sourced from Asia and North America, are too warm and moist to penetrate the cool temperatures creating the dome, however these areas can contribute to pollutants found in the lower latitudes of the Arctic (ie Greenland) (Law and Stohl, 2007). 

Arctic haze: a consequence of aerosol pollution

Variability in Arctic Haze concentration (Law and Stohl, 2007)

Arctic Haze consists of a mixture of Sulphates, Nitrates, Black Carbon and dust aerosols. Haze, containing a high concentration of aerosols, very effectively scatter solar radiation (Scnell, 1984). This haze demonstrates seasonal variability. Maximum levels of haze are witnessed in late winter and early spring, as removal processes recede in the dry season. Figure one shows the long term (A) and seasonal variation (B) in Arctic haze concentrations. The main impact of this Haze is the reduction is visibility, mostly effecting planes and shipping vessels travelling through the area. Furthermore the haze can deposit particulates on the snowy surface which absorb radiation and reduce Arctic Albedo (Rink et al., 2004). Albedo is the ability of a surface to reflect radiation. Snow has a high albedo but the deposition of particulates lower this and cause this snow to melt at a faster rate than it otherwise naturally would.

Enjoy this post? GOOD, as there are plenty more to come!  Long range pollution, and the threats associated, are not as widely discussed as the threats of climate change, because of this i feel this would be a very engaging topic to continue to focus on.

Until next time!