Tomasz Petelski

Aerosols in polar regions: A historical overview based on optical depth and in situ observations

Large sets of filtered actinometer, filtered pyrheliometer and Sun photometer measurements have been carried out over the past 30 years by various groups at different Arctic and Antarctic sites and ...

Marine aerosol fluxes over open sea calculated from vertical concentration gradients

Abstract Sea spray emission fluxes were calculated on the basis of vertical gradients of the aerosol concentration from experimental data collected with a laser particle counter during two polar scientific cruises carried out in July and August 2000 and 2001, and during cruises in the Baltic Sea in October 2000, and May and October 2001. Calculated fluxes range between 103 and 10 7 m −2 s −1 .

Study of Vertical Structure of Aerosol Optical Properties with Sun Photometers and Ceilometer During the MACRON Campaign in 2007

This paper presents the measurements of a vertical structure of aerosol optical properties performed during the MACRON (Maritime Aerosol, Clouds and Radiation Observation in Norway) campaign, which took place in July and August 2007 at ALOMAR observatory on Andøya island (69.279°N, 16.009°E, elevation 380 m a.s.l.). The mean value of the aerosol optical thickness (AOT) at 500 nm during campaign was 0.12. Significant increase of the AOT above longtime mean value was observed on 7 and 8 August 2007 when the AOT exceeded 0.4 at 500 nm. Analyses of back trajectories show the aerosol transported from over Africa and Central Europe. The aerosol extinction coefficient obtained from the synergy of ceilometer and sun photometer observations reached 0.05–0.08 km−1 (at 1064 nm) in the dust layer. The single scattering albedo at the ALOMAR observatory decreased during the dust episode to 0.93–0.94, which indicates some absorptive aerosols in the lower PBL.

Studies of aerosols advected to coastal areas with the use of remote techniques

This paper presents the results of the studies of aerosol optical properties measured using lidars and sun photometers. We describe two case studies of the combined measurements made in two coastal zones in Crete in 2006 and in Rozewie on the Baltic Sea in 2009. The combination of lidar and sun photometer measurements provides comprehensive information on both the total aerosol optical thickness in the entire atmosphere as well as the vertical structure of aerosol optical properties. Combination of such information with air mass back-trajectories and data collected at stations located on the route of air masses provides complete picture of the aerosol variations in the study area both vertically and horizontally. We show that such combined studies are especially important in the coastal areas where depending on air mass advection directions and altitudes the influence of fine or coarse mode (in this case possibly sea-salt) particles on the vertical structure of aerosol optical properties is an important issue to consider.

Studies of Aerosol Optical Depth with the Use of Microtops II Sun Photometers and MODIS Detectors in Coastal Areas of the Baltic Sea

In this paper we describe the results of a research campaign dedicated to the studies of aerosol optical properties in different regions of both the open Baltic Sea and its coastal areas. During the campaign we carried out simultaneous measurements of aerosol optical depth at 4 stations with the use of the hand-held Microtops II sun photometers. The studies were complemented with aerosol data provided by the MODIS. In order to obtain the full picture of aerosol situation over the study area, we added to our analyses the air mass back-trajectories at various altitudes as well as wind fields. Such complex information facilitated proper conclusions regarding aerosol optical depth and Ångström exponent for the four locations and discussion of the changes of aerosol properties with distance and with changes of meteorological factors. We also show that the Microtops II sun photometers are reliable instruments for field campaigns. They are easy to operate and provide good quality results.

Annual changes of aerosol optical depth and Ångström exponent over Spitsbergen

In this work we present the annual changes of two major, climate related aerosol optical parameters measured at three Spitsbergen locations, Ny-Alesund, Longyearbyen and Hornsund over a period between 2000 and 2012. We discuss the changes of aerosol optical depth (AOD) at 500 nm and the Angstrom exponent (AE) (440–870 nm) measured with use of different types of sun photometers. For the measurement data we adopted several data quality assurance techniques and the calibration of the instruments was taken into consideration. The results obtained show that marine source has been a dominating of aerosol sources over Spitsbergen. Some years (2005, 2006, 2008 and 2011) show very high values of AOD due to strong aerosol events such as the Arctic Haze. In general the mean AOD values increase over the period of 2000 and 2012 over Spitsbergen. This may indicate the presence of larger scale of atmospheric pollution in the region.

Aerosol Optical Depth Measured at Different Coastal Boundary Layers and Its Links with Synoptic-Scale Features

This paper presents the results of measurements of aerosol optical properties which were made between 2006 and 2008 within the framework of various international projects in different locations such as Spitsbergen, northern Norway and Crete. The investigations were made under different baric topography conditions and in various seasons of the year which facilitated the investigations of spatial and temporal dependencies between upper troposphere mass state and spectral variations of aerosol properties. The results of aerosol optical depth (AOD) measurements showed significant episodes during which jet stream events (300 hPa surface) over the Arctic were present. The mean spectral characteristics of AOD from “before” and “after” the event differ by 0.14 versus the “during” phase of the episode. The macrometeorological relative topography charts shown also the relationships between the 500 hPa, close sea-level pressure SLP (1,000 hPa) charts surfaces and the attenuation caused by aerosol scattering and absorption in vertical profiles during the afternoon hours.

Modelling and Observation of Mineral Dust Optical Properties over Central Europe

This paper is focused on Saharan dust transport to Central Europe/Poland; we compare properties of atmospheric Saharan dust using data from NAAPS, MACC, AERONET as well as observations obtained during HyMountEcos campaign in June 2012. Ten years of dust climatology shows that long-range transport of Saharan dust to Central Europe is mostly during spring and summer. HYSPLIT back-trajectories indicate airmass transport mainly in November, but it does not agree with modeled maxima of dust optical depth. NAAPS model shows maximum of dust optical depth (~0.04–0.05, 550 nm) in April–May, but the MACC modeled peak is broader (~0.04). During occurrence of mineral dust over Central-Europe for 14% (NAAPS) / 12% (MACC) of days dust optical depths are above 0.05 and during 4% (NAAPS) / 2.5% (MACC) of days dust optical depths exceed 0.1. The HyMountEcos campaign took place in June–July 2012 in the mountainous region of Karkonosze. The analysis includes remote sensing data from lidars, sunphotometers, and numerical simulations from NAAPS, MACC, DREAM8b models. Comparison of simulations with observations demonstrates the ability of models to reasonably reproduce aerosol vertical distributions and their temporal variability. However, significant differences between simulated and measured AODs were found. The best agreement was achieved for MACC model.

Reply to comment by Edgar L Andreas on ''Vertical coarse aerosol fluxes in the atmospheric surface layer over the North Polar Waters of the Atlantic''

[1] We are grateful for the interest Edgar L Andreas took in our work. His comments [Andreas, 2007] on our paper [Petelski and Piskozub, 2006] are insightful and confirm the methodology we chose, the aerosol concentration gradient, as a step forward toward achieving a reliable estimation of the aerosol production function. The difference between our approach and the recalculation of our results by Andreas [2007] is the value of the von Karman constant analogue for the aerosol flux. [2] It is not obvious that the dimensionless parameter of the logarithmic profile of aerosol concentration needs to be identical to the von Karman constant. The physics of momentum flux and aerosol flux are identical because we assume Monin-Obukhov similarity, but that implies only the existence of such a constant, not its value. Andreas gives theoretical reasons for its value to be identical to the Karman constant (approximately 0.40). We implicitly assumed it to be 1.0. Hence the approximate 2.5-fold difference of calculated fluxes in our original paper and in the comment by Andreas (approximate because we presented best fit flux functions for each wind speed bin data separately, which makes each of them differ from values of the ‘‘universal’’ function, namely, equation (5) of Petelski and Piskozub [2006], derived from the complete data set). However, we believe that the only way this problem can be solved is by experimental determination of the constant value. Until better data are available (one possibility is eddy correlation measurements in the open sea), our aerosol concentration data processed using the dry deposition method [Smith et al., 1993] may be the best calibration of the coefficient. Results presented in Figures 9 and 10 of Petelski and Piskozub [2006] (the ‘‘Eq(10)’’ lines) seem to suggest that the coefficient may be higher than the von Karman constant, possibly even closer to the value we implicitly chose (1.0). Also, the only eddy correlation measurements of aerosol concentration [Nilsson and Rannik, 2001] in the open sea, measured in the same areas as our data, seem to suggest that the flux functions favored by Andreas [2002] may be underestimated, further strengthening our estimation of the coefficient value. [3] Even with the above disagreements with Andreas [2007], we believe that his analysis of the influence of the flux coefficient choice on the results moves us forward toward a consensus on the marine aerosol source function. Even a 2.5-fold difference in the function value is minor compared to the several orders of magnitude range of functions reviewed by Andreas [2002]. However, further studies using more than one method of aerosol flux estimation are needed to narrow the von Karman constant–related uncertainty.

Aerosol properties and radiative forcing for three air masses transported in Summer 2011 to Sopot, Poland

Properties of atmospheric aerosols and solar radiation reaching the Earth’s surface were measured during Summer 2011 in Sopot, Poland. Three cloudless days, characterized by different directions of incoming air-flows, which are typical transport pathways to Sopot, were used to estimate a radiative forcing due to aerosols present in each air mass.