Aerosol decadal trends – Part 1. In-situ optical measurements at GAW and IMPROVE stations ...

• Main Authors: Collaud Coen, Martine, Andrews, Elisabeth, Asmi, Ari, Baltensperger, Urs, Bukowiecki, Nicolas, Day, Derek, Fiebig, Markus, Fjaeraa, Ann Mari, Flentje, Harald, Hyvärinen, Antti-Pekka, Jefferson, Anne, Jennings, Stephen G., Kouvarakis, Giorgos, Lihavainen, Heikki, Lund Myhre, Cathrine, Malm, William, Mihalopoulos, Nikolaos, Molenar, John, O'Dowd, Colin, Ogren, John A., Schichtel, Bret, Sheridan, Patrick, Virkkula, Aki, Weingartner, Ernest, Weller, Rolf, Laj, Paolo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus 2013
• Subjects: 550 - Geowissenschaften; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.26041/fhnw-8161; https://irf.fhnw.ch/handle/11654/44356

Currently many ground-based atmospheric stations include in-situ measurements of aerosol physical and optical properties, resulting in more than 20 long-term (> 10 yr) aerosol measurement sites in the Northern Hemisphere and Antarctica. Most of these sites are located at remote locations and monitor the aerosol particle number concentration, wavelength-dependent light scattering, backscattering, and absorption coefficients. The existence of these multi-year datasets enables the analysis of long-term trends of these aerosol parameters, and of the derived light scattering Ångström exponent and backscatter fraction. Since the aerosol variables are not normally distributed, three different methods (the seasonal Mann-Kendall test associated with the Sen's slope, the generalized least squares fit associated with an autoregressive bootstrap algorithm for confidence intervals, and the least-mean square fit applied to logarithms of the data) were applied to detect the long-term trends and their magnitudes. To ...