Properties of Arctic Aerosol Based on Sun Photometer Long-Term Measurements in Ny-angstrom lesund, Svalbard

Grassl, Sandra und Ritter, Christoph (2019): Properties of Arctic Aerosol Based on Sun Photometer Long-Term Measurements in Ny-angstrom lesund, Svalbard. In: Remote Sensing, Bd. 11, Nr. 11, 1362

Abstract

On the basis of sun photometer measurements located at the German-French polar research base AWIPEV in Ny-angstrom lesund (78.923 degrees N, 11.928 degrees E), Svalbard, long-term changes (2001-2017) of aerosol properties in the European Arctic are analyzed with the main focus on physical aerosol properties like Aerosol Optical Depth (AOD) and the angstrom ngstrom exponent during the Arctic haze season in spring compared with summer and autumn months. In order to gain more information from the photometer data and to reduce the error of fitting the data to the angstrom ngstrom law, a new approach with an angstrom ngstrom exponent, which depends linearly on wavelength, is presented in this paper. With the Mie program of libRadtran, a calculator for long- and short-wave radiation through the Earth's atmosphere, artificial aerosol size distributions were created to extend the physical understanding of this modified angstrom ngstrom law. Monthly means of the measured AOD of the years 1994-2017 are presented to analyze long-term changes of aerosol properties and its load. Because photometer data in general have no height information, a comparison with a Lidar located at the same site is presented. The so-obtained data are then compared with the previous Mie calculus. More homogeneous aerosol properties were found during spring and more heterogeneous in summer. To study possible aerosol sources and sinks, five-day back-trajectories were calculated with the FLEXPART model at three different arriving heights at 11 UTC in the village Ny-angstrom lesund. Besides the pollution pathway of the aerosol into the European Arctic based on the calculated back-trajectories, the influence of the boundary layer parameterized by the lowermost 100 hPa atmospheric layer is analyzed and compared to the measured aerosol load by the photometer in Ny-angstrom lesund additionally. During spring, the open ocean acts as a sink for aerosols, whereas sea ice clearly reduces their sinks. Hence, trajectories over sea ice are correlated to higher aerosol loads. Thus, both sources and sinks must be considered to understand aerosol occurrences in the Arctic.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• Sprache: Englisch