FALCON: a new approach to processing fluxes of aerosols

Abstract

The removal processes for atmospheric aerosols impact the radiative balance of Earth and how nutrients and pollutants move. Dry deposition is poorly modeled globally and over many types of surfaces compared to wet deposition. Important surface types on Earth, like the ocean and cryosphere, can be better understood by generating larger datasets of dry deposition measurements over those surface types. Aerosol properties, such as size, influence deposition in addition to surface and meteorological properties. More size-dependent dry deposition measurements can help models improve their dry deposition estimates, especially if those measurements have smaller uncertainties. Dry deposition velocities can be calculated from vertical aerosol fluxes. Fluxes of aerosols are generally noisier than gas or energy fluxes but can still be found with the eddy covariance technique when fluxes are measured over a long period of time. Using the eddy covariance technique to find aerosol fluxes requires fast (10Hz) measurements using two adjacent instruments. Aerosol concentrations are collected by a portable optical particle spectrometer (POPS) and wind velocities are found with a sonic anemometer. We demonstrate one way of calculating vertical aerosol fluxes over various surfaces. EddyPro and custom scripts process anemometer and POPS data into long-term and continuous flux datasets. This document provides instructions on each step of processing data, starting from the raw files produced and ending at a point where fluxes and deposition velocities are calculated.