Sources, Load, Vertical Distribution, and Fate of Wintertime Aerosols North of Svalbard From Combined V4 CALIOP Data, Ground‐Based IAOOS Lidar Observations and Trajectory Analysis

Abstract

We have analyzed aerosol properties at the regional scale over high Arctic north of Svalbard between October 2014 and June 2015 from version 4 (V4) CALIOP (Cloud and Aerosol Lidar with Orthogonal Polarization) spaceborne observations and compared results with surface lidar observations from IAOOS (Ice‐Atmosphere‐Ocean Observing System) platforms. CALIOP data indicate a maximum in aerosol occurrence at the end of winter attributed to low‐level (0–2 km) and midtropospheric (2–5 km) particles identified in CALIOP V4 product as being mostly of dust origin. Another maximum was observed in October–December attributed to clean marine particles below 2 km and smoke and dust above. The 532 nm aerosol extinction was in the range 1–8 Mm−1 (0–2 km), 1–18 Mm−1 (2–5 km), and 0–6 Mm−1 (5–10 km), a factor 2 lower compared to values previously reported using CALIOP V3 data set. Aerosols are identified from trajectory analyses to originate mostly from Russia/Europe at all altitudes, and also North America above 2 km, and it is concluded that dust and clean marine types are most probably overrepresented in the analyzed CALIOP data set. It is proposed that most part of dust types are diamond dust, while part of clean marine are polluted species, as corroborated from colocated polarized lidar IAOOS observations. IAOOS observations allowed confirming the identified sensitivity of CALIOP with a particle backscatter coefficient of ~0.001 km−1 sr−1 at 532 nm. For optically thicker layers CALIOP is shown to be a valuable tool to follow transport of aerosol layers in the Arctic and identify their possible modifications.

Discriminating between clouds and aerosols in the CALIOP version 4.1 data products

“…13d) indicate that most of these air parcels were originated and lifted up from the surface close to the Taklimakan Desert within the previous 5 days. These layers are thus likely dust transported from the lower latitudes, as demonstrated by Di Pierro et al (2011Pierro et al ( , 2013. Many of these layers were misclassified as ice clouds in V3, as shown in Fig.…”

“…Pollution and dust from Asian sources can reach the Arctic in 3 to 5 days, carried by midlatitude cyclones (Di Pierro et al, 2011, 2013. In the earlier CALIOP data product releases, dust layers over the Arctic could be misclassified by the CAD algorithm as ice clouds (Di Pierro et al, 2011). An example measured at 18:28:54 UTC on 1 March 2008 is shown in Fig.…”

“…For instance, dense aerosol (dust) layers over the Taklimakan Desert are sometimes misclassified as clouds in the V3 data products (Jin et al, 2014). Dust layers that are lofted from the Asian deserts and transported northward to the Siberian and American Arctic regions are often classified as ice clouds (Di Pierro et al, 2011, 2013. Also, smoke layers at high altitudes were occasionally misclassified as cirrus cloud by the V3 CAD algorithm (Miller et al, 2011;.…”

“…The Arctic regions have long been known to be impacted by aerosols from midlatitude sources, with the primary evidence being the springtime haze in the lower troposphere (Garrett and Verzella, 2008). Pollution and dust from Asian sources can reach the Arctic in 3 to 5 days, carried by midlatitude cyclones (Di Pierro et al, 2011, 2013. In the earlier CALIOP data product releases, dust layers over the Arctic could be misclassified by the CAD algorithm as ice clouds (Di Pierro et al, 2011).…”

Interrelations between surface, boundary layer, and columnar aerosol properties derived in summer and early autumn over a continental urban site in Warsaw, Poland

“…A number of publications have highlighted aerosol studies that use backward trajectories to interpret the possible aerosol source/type based on optical properties of observed aerosol and on the origin of air masses containing aerosol (e.g. Dörnbrack et al, 2010; Mona et al, Table 1. Literature review based on the values of the lidar-derived particle optical properties used for the interpretation of aerosol measured over the RS-Lab in Warsaw.…”