Effect of Heat Wave Conditions on Aerosol Optical Properties Derived from Satellite and Ground-Based Remote Sensing over Poland

Abstract

Abstract:During an exceptionally warm September in 2016, unique and stable weather conditions contributed to a heat wave over Poland, allowing for observations of aerosol optical properties, using a variety of ground-based and satellite remote sensors. The data set collected during 11-16 September 2016 was analysed in terms of aerosol transport (HYbrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT)), aerosol load model simulations (Copernicus Atmosphere Monitoring Service (CAMS), Navy Aerosol Analysis and Prediction System (NAAPS), Global Environmental Multiscale-Air Quality (GEM-AQ), columnar aerosol load measured at ground level (Aerosol Robotic NETwork (AERONET), Polish Aerosol Research Network (PolandAOD)) and from satellites (Spinning Enhanced Visible and Infrared Imager (SEVIRI), Moderate Resolution Imaging Spectroradiometer (MODIS)), as well as with 24/7 PollyXT Raman Lidar observations at the European Aerosol Research Lidar Network (EARLINET) site in Warsaw. Analyses revealed a single day of a relatively clean background aerosol related to an Arctic air-mass inflow, surrounded by a few days with a well increased aerosol load of differing origin: pollution transported from Germany and biomass burning from Ukraine. Such conditions proved excellent to test developed-in-house algorithms designed for near real-time aerosol optical depth (AOD) derivation from the SEVIRI sensor. The SEVIRI AOD maps derived over the territory of Poland, with an exceptionally high resolution (every 15 min; 5.5 × 5.5 km 2 ), revealed on an hourly scale, very low aerosol variability due to heat wave conditions. Comparisons of SEVIRI with NAAPS and CAMS AOD maps show strong qualitative similarities; however, NAAPS underestimates AOD and CAMS tends to underestimate it on relatively clean days (<0.2), and overestimate it for a high aerosol load (>0.4). A slight underestimation of the SEVIRI AOD is reported for pixel-to-column comparisons with AODs of several radiometers (AERONET, PolandAOD) and Lidar (EARLINET) with high correlation coefficients (r 2 of 0.8-0.91) and low root-mean-square error (RMSE of 0.03-0.05). A heat wave driven increase of the boundary layer height of 10% is accompanied with the AOD increase of 8-12% for an urban site dominated by anthropogenic pollution. Contrary trend, with an AOD decrease of around 4% for a rural site dominated by a long-range transported biomass burning aerosol is reported. There is a positive feedback of heat wave conditions on local and transported pollution and an extenuating effect on transported biomass burning aerosol. The daytime mean SEVIRI PM2.5 converted from the SEVIRI AODs at a pixel representative for Warsaw is in agreement with the daily mean PM2.5 surface measurements, whereby SEVIRI PM2.5 and Lidar-derived Ångström exponent are anti-correlated.

Modification of Local Urban Aerosol Properties by Long-Range Transport of Biomass Burning Aerosol

“…Over Europe, the cloudless conditions are often related to persistent for several days, quasi-stationary high pressure systems covering large geographical areas of the continent. Such weather dynamics provide an excellent test-bed for performing quasi-continuous ground-based passive and/or active remote sensing of optical properties of aerosols suspended in the air above the measurement site, whether on a local [3][4][5] or regional scale [6,7]. Such conditions also give great opportunities for retrieval of aerosol optical properties from satellite remote sensing (MODIS, SEVIRI), which are obviously hindered by cloud occurrence [8,9].…”

“…The altitude of the boundary layer top, as well as vertical change of wind speed and temperature significantly impact vertical distribution of the aerosol optical and microphysical properties in the lower troposphere [11][12][13][14]. They are found to also have an effect on concentrations of air pollutants, specifically over large cities [5,15,16]. Turbulence diffusion and boundary layer height are important meteorological factors affecting air pollution episodes, which is evident from their negative correlations with near-surface particulate matter of a size of less than 2.5 µm (PM 2.5 ) [17].…”

“…Turbulence diffusion and boundary layer height are important meteorological factors affecting air pollution episodes, which is evident from their negative correlations with near-surface particulate matter of a size of less than 2.5 µm (PM 2.5 ) [17]. On the other hand, anti-correlations of boundary layer height and surface PM 2.5 with the Ångström exponent are discernible for highly polluted urban atmosphere [5].…”

“…Often such fire-induced aerosols are observed at long distances from the source [13,24,25] and/or spread over large areas [7,26]. Depending on specific weather circulation, the fire-induced aerosol transport can be heat wave driven [3,5]. Both local and long-range transported wildfire aerosols can have a large impact on typically observed aerosol properties and therefore their occurrence over particular areas leads to large changes of radiative fluxes [22,27,28].…”

An Overview of Hand held Sun Photometer Measurements of Atmospheric Aerosols in New Orleans, Louisiana: A case study of the Xavier University Study Site

“…Aerosol measurements are best understood in the context of the other atmospheric measurements [14]. There may be observable relationships between aerosols and temperature, precipitation, relative humidity or barometric pressure.…”