One year of measurements with a POM02 sun-sky radiometer at an Alpine Euroskyrad station

[ABSTRACT]A new PREDE POM02 sun-sky radiometer was installed in Aosta (7.3570E, 45.7422N, 570 m a.s.l.), northern Italy, in May 2012. The site is located in an Alpine valley, in a semi-rural context, just out-of-town and partially influenced by anthropogenic activity both on local (emissions from vehicles, heating systems, steel mill) and regional (advection from the Po Valley) scales. Local meteorological phenomena such as thermal inversions, mountain-valley breezes and F?hn winds strongly condition the aerosol load at the measurement site. The instrument, managed by the Environmental Protection Agency (ARPA) of the Aosta Valley, is used as ancillary instrumentation in the framework of the research at the solar observatory and as a fundamental data source for radiative transfer modeling. Furthermore, it represents an original link between solar and air quality monitoring programs. Indeed, measuring the aerosol optical properties may help in identifying possible sources of particulate matter and in characterizing it. The site has joined the EuroSkyRad network (www.euroskyrad.net) and both Skyrad 4.2 and ESR.pack inversion products are daily available. Retrievals from Skyrad 4.2 are obtained by using both direct and diffuse radiation measurements, mirroring the Skynet inversions (atmos.cr.chiba-u.ac.jp). The products (aerosol optical thickness, Angstrom exponent, single scattering albedo, refractive index and volume size distribution) are presently provided at Level L0 and Level L1.1, since the cloud screening by means of measurements of pyranometer/pyrgeometer instruments needed in order to provide Level 1.2 data can not be performed, yet. Retrievals from ESR.pack are obtained by using only direct measurements (Sunrad module) and cloud screening is performed according to Estelles et al. (2012). The inversion of direct-only measurements resulted very important in the Aosta site. Indeed, two typical effects of the Alpine region prevent the inversion of almucantar scans, strongly reducing (>50%) the number of measurement days: the recurring presence of scattered clouds due to the complex orography and the mountain obstruction for solar zenith angles larger than 70°. First results from one year of measurements (processed by both Skyrad4.2 and ESR/Sunrad) will be presented. Correlations with in-situ measurements of fine particulate matter (PM), wind direction and speed and long-range trajectories will be shown based on several case studies. Finally, AOD measurements by our POM02 and a colocated Brewer spectrophotometer will be compared in the UV and visible range.

https://opac.ll.chiba-u.jp/da/curator/107460/

https://opac.ll.chiba-u.jp/da/curator/107460/ceresIntlSympo-19-P038.pdf

Chiba University. Center for Environmental Remote Sensing

千葉大学環境リモートセンシング研究センター

会議発表用資料

Proceedings of the CEReS international symposium = CEReS国際シンポジウム資料集

19

38

39

2013-07-04

publisher

環境リモートセンシング研究センター「CEReSシンポジウム資料集」