Abstract. Concentration of radon (222Rn) in the near-ground atmosphere has been measured quasi-continuously from January 2005 to December 2009 at two continental sites in Europe: Heidelberg (south-west Germany) and Krakow (southern Poland). The atmosphere was sampled at ca. 30 and 20 m above the local ground. Both stations were equipped with identical instruments. Regular observations of 222Rn were supplemented by measurements of surface fluxes of this gas in the Krakow urban area, using two different approaches. The measured concentrations of 222Rn varied at both sites in a wide range, from less than 2.0 Bq m−3 to approximately 40 Bq m−3 in Krakow and 35 Bq m−3 in Heidelberg. The mean 222Rn content in Krakow, when averaged over the entire observation period, was 30% higher than in Heidelberg (5.86 ± 0.09 and 4.50 ± 0.07 Bq m−3, respectively). Distinct seasonality of 222Rn signal is visible in the obtained time series of 222Rn concentration, with higher values recorded generally during late summer and autumn. The surface 222Rn fluxes measured in Krakow also revealed a distinct seasonality, with broad maximum observed during summer and early autumn and minimum during the winter. When averaged over a 5-year observation period, the night-time surface 222Rn flux was equal to 46.8 ± 2.4 Bq m−2 h−1. Although the atmospheric 222Rn levels at Heidelberg and Krakow appeared to be controlled primarily by local factors, it was possible to evaluate the "continental effect" in atmospheric 222Rn content between both sites, related to gradual build-up of 222Rn concentration in the air masses travelling between Heidelberg and Krakow. The mean value of this build-up was equal to 0.78 ± 0.12 Bq m−3. The measured minimum 222Rn concentrations at both sites and the difference between them was interpreted in the framework of a simple box model coupled with HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) analysis of air mass trajectories. The best fit of experimental data was obtained for the mean 222Rn flux over the European continent equal to 52 Bq m−2 h−1, the mean transport velocity of the air masses within the convective mixed layer of the planetary boundary layer (PBL) on their route from the Atlantic coast to Heidelberg and Krakow equal to 3.5 m s−1, the mean rate constant of 222Rn removal across the top of the PBL equal to the 222Rn decay constant and the mean height of the convective mixed layer equal to 1600 m.

A B S T R A C T Regular observations of atmospheric mixing ratios of CO 2 and CH 4 , combined with sodar measurements of the mixing layer height in the lower troposphere were used to assess night-time surface fluxes of these gases in the urban environment (Krakow, southern Poland). The measurements performed over the 4-yr period (May 2005-May 2009) revealed a distinct seasonality of surface night-time fluxes of CO 2 , with the minimum of ca. 2 mmol m −2 h −1 during winter months and the maximum of ca. 20 mmol m −2 h −1 observed during summer months. The observed seasonality was induced by the biospheric component (soil respiration) which dominates the measured surface CO 2 fluxes during summer months. The surface fluxes of CH 4 scatter between ca. 50 and 200 μmol m −2 h −1 , without clear seasonal trend. Significant flux of CH 4 into the atmosphere (mean value over the whole observation period equal to ca. 97 μmol m −2 h −1 ), indicates a presence of relatively strong methane source on the investigated area. This source is linked to methane leakages from the city gas distribution network.

The investigation of the orientation of galaxies is a standard test concerning to scenarios of galaxy formation, because different theories of galaxy formation make various predictions regarding to the angular momentum of galaxies. The new method of analysis of the alignment of galaxies in clusters was proposed in the paper Godlowski (2012) and now is improved. We analyzed the distribution of the position angles of the galaxy major axes, as well as the distribution of two angles describing the spatial orientation of galaxy plane, which gives the information about galaxy angular momenta. We discuss the orientation of galaxies in groups and clusters of galaxies. The results show the dependence of the alignment with respect to clusters richness. The implications of the results for theories of galaxy formation are discussed as well.Comment: Preliminary version of the paper from Astrophysics 56, p.322 send to Astrofizika editio

Abstract:The paper presents a method of identifying distant emission sources of fi ne particulate matter PM 2.5 affecting signifi cantly PM 2.5 concentrations at a given location. The method involves spatial analysis of aggregate information about PM 2.5 concentrations measured at the location and air masses backward trajectories calculated by HYSPLIT model. The method was examined for three locations of PM 2.5 measurement stations (Diabla Góra, Gdańsk, and Katowice) which represented different environmental conditions. The backward trajectories were calculated starting from different heights (30, 50, 100 and 150 m a. g. l.). All points of a single backward trajectory were assigned to the PM 2.5 concentration corresponding to the date and the site of the beginning of trajectory calculation. Daily average concentrations of PM 2.5 were used, and in the case of Gdańsk also hourly ones. It enabled to assess the effectiveness of the presented method using daily averages if hourly ones were not available. Locations of distant sources of fi ne particulate matter emission were determined by assigning to each grid node a mean value of PM 2.5 concentrations associated with the trajectories points located within the so-called search ellipse. Nearby sources of fi ne particulate matter emission were eliminated by fi ltering the trajectories points located close to each other (so-called duplicates).

Various morphometric methods used for wind-speed determination in urban areas inside the roughness sublayer have been tested in Krakow, Poland, using a hybrid modelling system. The hybrid modelling system combines the classic numerical meteorological modelling using ALADIN, MM5, and CALMET models with empirical, non-logarithmic relations determined on the basis of a wind-tunnel experiment. In the hybrid modelling system, the horizontally-averaged wind speed is determined using the displacement height d, roughness length z 0 , and an attenuation coefficient α. These parameters are determined using laser scanning data obtained in the MONIT-AIR project. The variability of the selected morphometric parameters in Krakow, the role of the size of the area from which they are determined and the consequences of replacing the frontal area index by the plan area index are analyzed. The different methods used to determine d, z 0, and α are compared and the correctness of the procedures describing the wind profile are verified by comparisons with wind-speed data from road stations, with the wind speed measured between the traffic lanes or at the roadside at a height of 4 m, at standard meteorological stations, and from masts situated on buildings. It is shown that the use of a parametrization based on large-eddy simulations prepared for explicitly resolved buildings in Tokyo and Nagoya in Japan, and taking the maximum instead of the average height of building in empirical relations, significantly improves the modelling results, especially above the average height of buildings.

No abstract

Abstract. Specific activity of 222Rn in near-ground atmosphere has been measured quasi-continuously from January 2005 to December 2009 at two continental sites in Europe: Heidelberg (south-west Germany) and Krakow (southern Poland). Atmosphere was sampled at ca. 30 m and 20 m, respectively, above the local ground. Both stations were equipped with identical instrumentation. Regular observations of 222Rn were supplemented by measurements of surface fluxes of this gas in Krakow urban area, using two entirely different approaches. Atmospheric 222Rn concentrations varied at both sites in a wide range, from less than 2 Bq m−3 to approximately 40 Bq m−3 in Krakow and ca. 35 Bq m−3 in Heidelberg. Averaged over entire observation period, the 222Rn content in Krakow was approximately 30 % higher when compared to Heidelberg (5.86 ± 0.09 Bq −3 and 4.50 ± 0.07 Bq m−3, respectively). Distinct seasonality of 222Rn signal was visible in both presented time series, with higher values recorded generally during late summer and autumn. The surface 222Rn fluxes in Krakow also revealed a distinct seasonality, with broad maximum observed during summer and early autumn and minimum during the winter. Averaged over 5 yr observation period, the night-time surface 222Rn flux was equal 46.8 ± 2.4 Bq m−2 h−1. Although the atmospheric 222Rn levels at Heidelberg and Krakow appeared to be controlled primarily by local factors, it was possible to evaluate the "continental effect" in atmospheric 222Rn content between both sites, related to the gradual build-up of 222Rn concentration in the air masses travelling between Heidelberg and Krakow. The mean value of this load was equal 0.78 ± 0.12 Bq m−3. The measured minimum 222Rn concentrations at both sites and the difference between them was interpreted in the framework of a simple box model coupled with HYSPLIT analysis of air mass trajectories. Best fit of experimental and model data was obtained for the average 222Rn flux over the European continent equal 52 Bq m−2 h−1, the mean transport velocity of the air masses within convective mixed layer of PBL on their route from the Atlantic coast to Heidelberg and Krakow equal 3.5 m s−1, the mean rate constant of 222Rn removal across the top of PBL equal to the 222Rn decay constant and the mean height of the convective mixed layer height equal 1600 m.

Polluted air is dangerous to human life and health. Particulate matter, among others PM10, isone of the most harmful substances. In Maopolska and its capital Krakw, the concentrations ofharmful substances often exceed the standards set by the World Health Organization. Krakw,thanks to the ban on residential heating with solid fuels, has significantly reduced emissions ofpollution, but they remain high in the remaining part of the region, affecting air quality in thecapital as well. With the frequent occurrence of high concentrations of pollutants, in addition tothe necessary measures aimed at reducing emissions, forecasting of air pollutant concentrations isneeded to inform the population if normative concentrations are likely to be exceeded. The FAPPS(Forecasting of Air Pollution Propagation System), based on the AROME/MM5/CALMET/CALPUFF model ensemble, has been operating in Maopolska since 2014 and has been used tocreate pollution concentration forecasts for Krakw and Maopolska. In this study, the influence ofemissions from point sources on air quality in Maopolska was investigated based on the results ofmodellingwith this system. Modelling results indicate that this influence is negligible. The qualityof PM10 forecasts for four versions of the FAPPS system, differing in the meteorological modelused MM5 (Fifth-Generation Penn State/NCAR Mesoscale Model) or WRF (Weather Researchand Forecasting) and the emission input (2015 emissions from the Maopolska Marshals Office,updated with data from the City of Krakw for 2018, or the 2020 emission inventory from theCentral Emission Database) was tested. The quality of forecasts was assessed based on the resultsof measurements at the 22 air pollution monitoring stations for three smog episodes that occurredon 1117.11.2021, 1115.12.2021 and 1318.03.2022. The best results for Krakw were obtainedusing an approach based on the WRF model and the emission inventory from the Central EmissionDatabase, for which an RMSE (Root Mean Square Error) value of 30.02 g/m3 was obtained forselected episodes. In the case of Maopolska, the lowest RMSE value (33.58 g/m3) was obtainedfor the system using the emission inventory obtained from the Marshals Office and the WRF model. First tests indicate that changing the meteorological model from MM5 to WRF can lead toimproved modelling results, but, further research is needed to confirm it.