Aerosol connections between three distant continental stations

Abstract

A B S T R A C TThe present study is based on hourly aerosol particle and ancillary data taken at three stations in Northeastern Germany 150-200 km apart in the years 2009 through 2015 in order to investigate systematic process related differences that might show up when connecting their data with forward and backward air mass trajectories. The analysis of changes in the atmospheric aerosol during air mass transport between the stations focused on two low-pollution-to-high-pollution pathways of similar distance around 200 km. Despite rather different initial size distributions the increases in total concentration of particle number, volume, and black carbon agreed within 15%. Systematic variations were found in the different concentration increases as a function of time of day at which an interstation air mass transport took place that could be explained with related source and transport processes.With Radar-based precipitation data at the stations and along connecting trajectories sub-cloud particle scavenging was investigated. At each station sub-cloud particle scavenging coefficients were determined as a function of particle size between 10 and 700 nm diameter, and as a function of precipitation sums. Median particle scavenging coefficients taken over the central part of the size range of the study strongly increased between 0.2 and 1 mm of precipitation and then planed out towards higher precipitation values. With the particle scavenging coefficients determined at the individual stations and precipitation data along connecting trajectories the sub-cloud particle scavenging analysis was extended to wet scavenging along the transport paths yielding median sub-cloud scavenging ratios over the range 0.2-25 mm of precipitation sums with a non-linear shape similar to that of the median particle scavenging coefficients at the individual stations. Whereas in light precipitation more than 80% of the initial particles in the considered range survived 150-200 km of transport, more than 50% was scavenged by more than 15 mm of precipitation during aerosol transport.

Aerosol immission maps and trends over Germany with hourly data at four rural background stations from 2009 to 2018

“…aerosol dynamics are not considered at all. Possible future improvements concern trajectories with higher resolution, better meteorological information along the trajectories e.g., radarderived precipitation as used in Heintzenberg et al, (2018), emission inventories with higher spatiotemporal resolution and higher numbers of involved stations.…”

“…Hourly aerosol data from the three GUAN-stations during 2009 -2015 (NG ≥2011) have been utilized in a previous study (Heintzenberg et al, 2018) to understand aerosol processes during air mass transport between the stations. In the present study the data set was enlarged to include the additional station Collmberg and data at all stations from the years 2016 through 2018.…”