G. Milinevsky

Scaling effect in planetary waves over Antarctica

Detrended fluctuation analysis (DFA) was applied to the total ozone planetary waves 1 and 2 at the middle and high latitudes of the southern hemisphere that had been acquired by daily Total Ozone Mapping Spectrometer (TOMS) total ozone observations since 1979. The main aim of the analysis was to examine the ozone layer as a system invariant in a wide range of scales characterized by the fractal structure, and to search for the existence of long‐range correlations. The results show that fluctuations in the amplitude of wave 1 obey persistent long‐range power‐law correlations for time scales greater than about 4 days and less than about 3 months. This suggests that these fluctuations in small time intervals are closely related to the fluctuations in longer time intervals in a power‐law fashion (when the time intervals vary from about 4 days to about 3 months). Similar analysis applied to the amplitude of wave 2 revealed that this wave does not exhibit long‐range correlations.

Tree rings reveal extent of exposure to ionizing radiation in Scots pine Pinus sylvestris

Tree growth has been hypothesized to provide a reliable indicator of the state of the external environment. Elevated levels of background ionizing radiation may impair growth trajectories of trees by reducing the annual growth. Such effects of radiation may depend on the individual phenotype and interact with other environmental factors such as temperature and drought. We used standardized growth rates of 105 Scots pine Pinus sylvestris located near Chernobyl, Ukraine, varying in the level of background radiation by almost a factor 700. Mean growth rate was severely depressed and more variable in 1987–1989 and several other subsequent years, following the nuclear accident in April 1986 compared to the situation before 1986. The higher frequency of years with poor growth after 1986 was not caused by elevated temperature, drought or their interactions with background radiation. Elevated temperatures suppressed individual growth rates in particular years. Finally, the negative effects of radioactive contaminants were particularly pronounced in smaller trees. These findings suggest that radiation has suppressed growth rates of pines in Chernobyl, and that radiation interacts with other environmental factors and phenotypic traits of plants to influence their growth trajectories in complex ways.

Interannual variability of planetary waves in the ozone layer at 65° S

Planetary wave activity in the ozone layer was analysed using the Total Ozone Mapping Spectrometer (TOMS) satellite total ozone measurements. The area under study is southern latitude 65° S, the closest to the location of the Vernadsky station (65°15′ S, 64°16′ W). The time–longitude variations in the total ozone during August–December 1979–2003 are presented. The five‐month average distributions of the total ozone along the latitude circle of 65° S show the steady features of quasi‐stationary zonal distribution caused by superposition of the total wave numbers. The structure of wave number 1 is dominant. Interannual variations and long‐term trends of the total wave number amplitude and longitudinal position of the wave ridge (high ozone) and trough (low ozone) are described. Due to the wave amplitude increase the difference between low and high ozone in the opposite longitudinal sectors reached ca 30% in the early 2000s. During 1979–2003 the wave ridge position was relatively stable with the mean longitude of 152±15° E; however, the wave trough position drifted eastward from 55° W to the Greenwich meridian with the mean velocity of the long‐term drift of 23.6±7.2° per decade. Deviation of the quasi‐stationary wave characteristics relative to the mean tendency took place in 1988 and 2002.

Localization of aerosol sources in East-European region by back-trajectory statistics

A concentration-weighted trajectory method for aerosol source localization based on joint statistical analysis of aerosol column volume concentrations and back-trajectory data was used to estimate the spatial distribution of aerosol sources in the East-European region. The aerosol column volume concentration data measured at five AERONET network sites, Belsk, Minsk, Kyiv, Moldova/Kishinev, and Sevastopol, were used. The geographical areas responsible for increased aerosol content at the monitoring sites were mapped separately for coarse-mode and fine-mode aerosol fractions. The investigated area is located between 42° and 62° N in latitude and between 12° and 50° E in longitude. It was shown that the northeastern territories (in relation to the monitoring stations) give a small contribution to the coarse-mode aerosol content. The events of increased coarse-mode aerosol concentration have been caused by sources in the southeastern regions. On average, the air masses with a large content of coarse-mode aerosol particles were delivered to all stations from regions around Donetsk, Rostov-on-Don, and Kharkiv cities. The fine-mode aerosol fraction originated from areas of Tambov, Voronezh, and Kharkiv cities. The calculated aerosol source regions partly correspond to European Monitoring and Evaluation Programme data for eastern Europe. The cause of difference between calculated regions responsible for increased aerosol content at the monitoring sites and the sources of particle emission according to European Monitoring and Evaluation Programme data are discussed.

Aerosol layer properties over Kyiv from AERONET/PHOTONS sunphotometer measurements during 2008-2009

The AErosol RObotic NETwork (AERONET) is one of the most developed ground-based networks for aerosol monitoring. Radiative measurements (solar irradiance extinction, aureole brightness and sky light polarization) are used by the AERONET inversion retrieval technique to derive a wide variety of aerosol particle properties and parameters that are important for estimations of aerosol influences on climate change. Within the framework of scientific cooperation between Université de Lille 1 and Taras Shevchenko National University (TSNU) of Kyiv (Kiev), a CIMEL CE 318-2 sunphotometer has been operating at Kyiv since March 2008. This article presents a preliminary analysis of the columnar aerosol properties retrieved from Kyiv sunphotometer measurements and one case study with unusual behaviour of the aerosol parameters. Version 2 of the AERONET inversion products (spectral aerosol optical thickness (AOT), the Ångström parameter (α), single-scattering albedo (SSA), size distribution and refractive index, and aerosol radiative forcing estimations) is considered in the analysis, demonstrating variability of aerosol properties and radiative forcing at the Kyiv observational site during a 1-year period.

Decadal variability of winter temperatures in the Antarctic Peninsula region

Abstract Rapid climate warming has been observed in the region of the Antarctic Peninsula since the middle of the last century with the largest warming rate in the winter. Decadal variability of winter temperature on the regional scale was analysed using eight station datasets of the Antarctic Peninsula region. The Scientific Committee on Antarctic Research Reference Antarctic Data for Environmental Research from the period 1950–2009 were used. Fourier and wavelet transforms of the averaged temperature anomaly time series reveal a clear separation between the oscillations with three to eight year periods and a decadal oscillation with a period of around 16 years. On the Antarctic Peninsula region scale, 16 year periodicity in the winter temperature variability has not been described before. Both spectral components show similar spectral power and statistical significance (5–10%). This is evidence of their comparable importance for winter temperature changes in the Antarctic Peninsula region. The three to eight year periods are most probably related to the El Niño–Southern Oscillation and Antarctic Circumpolar Wave signals, but the 16 year oscillation has not been identified within the scope of this analysis. The possible effect of the decadal oscillation in the winter temperature trend estimate is discussed.

Estimation of solar UV radiation in maritime Antarctica using a nonlinear model including cloud effects

A new approach to the estimation of erythemally effective ultraviolet (EUV) radiation for all sky conditions that occur in maritime Antarctica is reported. The spatial variability of the total ozone content (TOC) and attenuation of the EUV radiation in the atmosphere are taken into consideration. The proposed nonlinear regression model of EUV radiation is described by a hyperbolic transmission function. The first results and the model validation for Vernadsky Station (formerly the British Faraday Station) during the period 2002–2005 show very good agreement with the measured values (R 2 = 99.2). The developed model was evaluated using daily doses of EUV radiation with respect to solar elevation angle and cloudiness. The mean average prediction error (MAPE) for cloudy (4.1–7.0 oktas) and overcast skies (7.1–8.0 oktas) varied between 4.0% and 4.3%, while for partly cloudy days (0–4.0 oktas) with high variability of cloud types during a day, MAPE reached 5.9%.

On the regional distinctions in annual cycle of total ozone in the northern midlatitudes

To better attribute the total ozone column (TOC) anomalies observed from the ozone measurements in Ukraine, the climatologies of annual ozone cycle along the latitudinal band 40–60° N with the 30° step in longitude have been analysed. Gridded satellite ozone data based on the merged ozone dataset over the period 1979–2011 are used. The results show that, similar to the known longitudinal dependences of both the total ozone itself and its decadal trends, the annual TOC cycle in the northern midlatitudes is also longitudinally dependent. The higher (lower) regional TOC level is associated with the leading (lagging) development of the annual cycle relative to the zonal mean climatology. Particularly, a 2- to 3-month lead of annual cycle in eastern Asia (120–150° E) in comparison with that in eastern Atlantic (0–30° W) exists. Revealed coupling between regionality and seasonality of the TOC in the northern midlatitudes may be involved in the regional climate variability and deserves further studies with higher temporal and spatial resolution.

Total ozone dependence of the difference between the empirically corrected EP-TOMS and high-latitude station datasets

A comparison was made of the ground-based and satellite total ozone content (TOC) measurements in the atmosphere over the Antarctic stations Vernadsky, Halley and Amundsen–Scott and the Arctic station Barrow. A similar discrepancy analysis was performed using the global network of ground-based ozonometric stations from the beginning of regular satellite observations in 1978. Slowing of the long-term global ozone losses has been observed during the past decade and a recovery of the ozone layer is forecast for the coming decades. Therefore, the accuracy requirements for ozone measurements are increasing, which, in turn, requires corresponding analysis of the measurement errors. In this work, the Earth Probe Total Ozone Mapping Spectrometer (EP-TOMS) satellite data from 1996 to 2005 were used. Satellite daily TOC values were taken using version 8 of the algorithm introduced in 2004 and empirically corrected in 2007. The most persistent features of the relative EP-TOMS–Dobson difference are: (1) a significant increase in dispersion during the period of the spring Antarctic ozone hole and (2) a differing dependence on total ozone in the trend tendency and significance for EP-TOMS and Dobson datasets. The results indicate the influence of the specific conditions during the Antarctic ozone hole on the possible precision that could be achieved in assessments of Montreal Protocol effects in the ozone layer over this region.

Atmospheric aerosol distribution in the Belarus-Ukraine region by the GEOS–Chem model and AERONET measurements

ABSTRACT We use a global chemical transport model, GEOS–Chem (Goddard Earth Observing System – Chemistry model), to simulate the spatial and temporal distribution of atmospheric concentrations of specific aerosol types over the Belarus-Ukraine region for period 2010–2013. Results of the model simulation are evaluated with observations from Aerosol Robotic Network (AERONET) sites. To provide accurate comparison, we convert simulated aerosol components concentration into coarse, fine, and total aerosol column volume concentrations taking into account the hygroscopic growth of particles. Model-predicted and remotely sensed aerosol volume concentrations are in reasonable agreement. Comparison of the GEOS–Chem model results to the spatial distribution of the aerosol sources of coarse- and fine-mode fractions for the region investigated shows correspondence in general for coarse mode but differences for fine mode.