Deposition of dinitrogen pentoxide, N₂O₅, to the snowpack at high latitudes

Abstract

Abstract. Dinitrogen pentoxide, N2O5, is an important nighttime intermediate in the oxidation of NOx that is hydrolysed on surfaces. We conducted a field campaign in Fairbanks, Alaska during November 2009 to measure the gradient and derive a flux (and deposition velocity) of N2O5 depositing to snowpack using the aerodynamic gradient method. The deposition velocity of N2O5 under Arctic winter conditions was found to be 0.59 ± 0.47 cm s−1, which is the first measurement of this parameter to our knowledge. Based on the measured deposition velocity, we compared the chemical loss rate of N2O5 via snowpack deposition to the total steady state loss rate and found that deposition to snowpack is at least 1/8th of the total chemical removal of N2O5 that is located within the first few meters above the ground surface.