Estonian Environment Agency
Estonian Environment Agency
Toll V.,University of Tartu |
Toll V.,Estonian Environment Agency |
Post P.,University of Tartu
Theoretical and Applied Climatology | Year: 2017
Daily 2-m temperature and precipitation extremes in the Baltic Sea region for the time period of 1965–2005 is studied based on data from the BaltAn65 + high resolution atmospheric reanalysis. Moreover, the ability of regional reanalysis to capture extremes is analysed by comparing the reanalysis data to gridded observations. The shortcomings in the simulation of the minimum temperatures over the northern part of the region and in the simulation of the extreme precipitation over the Scandinavian mountains in the BaltAn65+ reanalysis data are detected and analysed. Temporal trends in the temperature and precipitation extremes in the Baltic Sea region, with the largest increases in temperature and precipitation in winter, are detected based on both gridded observations and the BaltAn65+ reanalysis data. However, the reanalysis is not able to capture all of the regional trends in the extremes in the observations due to the shortcomings in the simulation of the extremes. © 2017 Springer-Verlag Wien
Voormansik T.,University of Tartu |
Voormansik T.,Estonian Environment Agency |
Rossi P.J.,Vaisala |
Moisseev D.,University of Helsinki |
And 3 more authors.
Meteorological Applications | Year: 2017
Four years (2011–2014) of the summer period (May–September) dual-polarization Doppler C-band weather radar data for Sürgavere, Estonia, were examined to determine the best indicator for cloud-to-ground lightning activity. Furthermore, the legacy radar-derived hail indicator probability of hail and the storm maximum reflectivity were compared with the polarimetric hydrometeor classification algorithm (HCA) to establish a link between them and ensure data continuity. The study is based on convective storm cells identified from radar reflectivity data, using a 35 dBZ reflectivity threshold. Applying this threshold to the radar data resulted in 123 360 individual storm cells. It was found that 33.9% of the identified cells produced lightning and 25.9% hail. The number of individual storm cells on average is highest in the afternoon at 1600 local time and the mean storm cell area is largest in the evening at 2100 local time. Echo top 15 dBZ (ET15), ET20 and ET25 achieved the highest scores in terms of critical success index (0.39, 0.39 and 0.38 respectively), Heidke skill score (0.24, 0.26, 0.27) and equitable threat score (0.14, 0.15, 0.16). The graupel class of the dual-polarization radar hydrometeor classification showed a similar performance to the 35 dBZ echo top. It was also shown that the reflectivity value just below 50 dBZ indicates the best skill for detection of hail, if HCA hail detection is used as the ground truth. The probability of hail value that shows the best agreement with the HCA hail class is 0.2. © 2017 Royal Meteorological Society
Loorits V.,Estonian Environment Agency
Journal of Physics: Conference Series | Year: 2017
Shape of optical spectrum of vibronic transition in one-dimensional model taking into account dynamical pseudo-Jahn-Teller effect was studied. Numerical calculations at large values of interaction parameter revealed periodic character of the envelope. This was interpreted as manifestation of Fermi resonance. © Published under licence by IOP Publishing Ltd.
Toll V.,University of Tartu |
Toll V.,Estonian Environment Agency |
Pagh Nielsen K.,Danish Meteorological Institute |
Rontu L.,Finnish Meteorological Institute |
Masek J.,Czech Hydrometeorological Institute
Atmospheric Chemistry and Physics | Year: 2016
The direct shortwave radiative effect of aerosols under clear-sky conditions in the Aire Limitee Adaptation dynamique Developpement InterNational-High Resolution Limited Area Model (ALADIN-HIRLAM) numerical weather prediction system was investigated using three shortwave radiation schemes in diagnostic single-column experiments: the Integrated Forecast System (IFS), acraneb2 and the hlradia radiation schemes. The multi-band IFS scheme was formerly used operationally by the European Centre for Medium Range Weather Forecasts (ECMWF) whereas hlradia and acraneb2 are broadband schemes. The former is a new version of the HIRLAM radiation scheme while acraneb2 is the radiation scheme in the ALARO-1 physics package. The aim was to evaluate the strengths and weaknesses of the numerical weather prediction (NWP) system regarding aerosols and to prepare it for use of real-time aerosol information. The experiments were run with particular focus on the August 2010 Russian wildfire case. Each of the three radiation schemes accurately (within ±4 % at midday) simulates the direct shortwave aerosol effect when observed aerosol optical properties are used. When the aerosols were excluded from the simulations, errors of more than +15 % in global shortwave irradiance were found at midday, with the error reduced to +10 % when standard climatological aerosols were used. An error of-11 % was seen at midday if only observed aerosol optical depths at 550 nm, and not observation-based spectral dependence of aerosol optical depth, single scattering albedos and asymmetry factors, were included in the simulations. This demonstrates the importance of using the correct aerosol optical properties. The dependency of the direct radiative effect of aerosols on relative humidity was tested and shown to be within ± 6% in this case. By modifying the assumptions about the shape of the IFS climatological vertical aerosol profile, the inherent uncertainties associated with assuming fixed vertical profiles were investigated. The shortwave heating rates in the boundary layer changed by up to a factor of 2 in response to the aerosol vertical distribution without changing the total aerosol optical depth. Finally, we tested the radiative transfer approximations used in the three radiation schemes for typical aerosol optical properties compared to the accurate DISORT model. These approximations are found to be accurate to within ±13 % even for large aerosol loads. © 2016 Author(s).
PubMed | Armenian National Academy of Sciences, Tauride Agrotechnology State University, Kaunas T. Ivanauskas Zoological Museum, Armenian National Agrarian University and 11 more.
Type: Journal Article | Journal: PloS one | Year: 2015
In the first continent-wide study of the golden jackal (Canis aureus), we characterised its population genetic structure and attempted to identify the origin of European populations. This provided a unique insight into genetic characteristics of a native carnivore population with rapid large-scale expansion. We analysed 15 microsatellite markers and a 406 base-pair fragment of the mitochondrial control region. Bayesian-based and principal components methods were applied to evaluate whether the geographical grouping of samples corresponded with genetic groups. Our analysis revealed low levels of genetic diversity, reflecting the unique history of the golden jackal among Europes native carnivores. The results suggest ongoing gene flow between south-eastern Europe and the Caucasus, with both contributing to the Baltic population, which appeared only recently. The population from the Peloponnese Peninsula in southern Greece forms a common genetic cluster with samples from south-eastern Europe (K approach in STRUCTURE, Principal Components Analysis [PCA]), although the results based on BAPS and the estimated likelihood in STRUCTURE indicate that Peloponnesian jackals may represent a distinct population. Moreover, analyses of population structure also suggest either genetic distinctiveness of the island population from Samos near the coast of Asia Minor (BAPS, most STRUCTURE, PCA), or possibly its connection with the Caucasus population (one analysis in STRUCTURE). We speculate from our results that ancient Mediterranean jackal populations have persisted to the present day, and have merged with jackals colonising from Asia. These data also suggest that new populations of the golden jackal may be founded by long-distance dispersal, and thus should not be treated as an invasive alien species, i.e. an organism that is non-native to an ecosystem, and which may cause economic or environmental harm or adversely affect human health. These insights into the genetic structure and ancestry of Baltic jackals have important implications for management and conservation of jackals in Europe. The golden jackal is listed as an Annex V species in the EU Habitats Directive and as such, considering also the results presented here, should be legally protected in all EU member states.
Keevallik S.,Tallinn University of Technology |
Vint K.,Estonian Environment Agency
Proceedings of the Estonian Academy of Sciences | Year: 2015
Daily maximum and minimum temperatures are analysed from long time series for three Estonian sites: Tallinn on the southern coast of the Gulf of Finland (1920–2013), Tartu in inland Estonia (1894–2013), and Pärnu on the northern coast of the Gulf of Riga (1878–2013). The probabilities of extreme temperatures (defined in the meteorological practice in Estonia as lower than – 30 °C in winter and higher than 30 °C in summer) and their successions (incl. cold and heat waves) are evaluated for the three sites. It is suggested that the thresholds based on upper or lower percentiles of the distributions of daily maxima/minima recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) are more suitable for the detection of cold and heat waves in Estonian climatic conditions than the current practice. © 2015, Estonian Academy Publishers. All rights reserved.
Iital A.,Tallinn University of Technology |
Kloga M.,Tallinn University of Technology |
Pihlak M.,Tallinn University of Technology |
Pachel K.,Tallinn University of Technology |
And 2 more authors.
Agriculture, Ecosystems and Environment | Year: 2014
Several studies have shown that the stream water quality in agricultural catchments could vary according to the changes in land use, production intensities and implemented agri-environmental measures. In present study we investigated the nitrogen content and temporal dynamics in concentration and loss in small streams and catchments in Estonia for the period 1992-2011. The studied catchments represent various agricultural production areas, management practices, soil types, geology and size. A statistical analysis using the Mann Kendall (MK) test was undertaken to discern monotone trends in time series of total nitrogen (TN) and nitrate nitrogen (NO3-N) concentrations for 8 sampling sites and TN loss for five sites, for which at least a data set of 10 years was available. Additionally the partial Mann-Kendall (PMK) test has been adapted to account for the influence of water discharge to the temporal trends in TN loss in five catchments. The MK trend test revealed one statistically significant (p < 0.05; two-sided test) upward trend in TN concentrations and two upward trends in NO3-N concentrations. Less significant (p < 0.08) upward trend in TN content was also noted in two streams. Overall, the TN concentrations were rather high and it ranged with 90% probability from 2.3 to 8.9 mg l-1 in the studied streams. The MK test revealed the statistically significant upward trend in TN loss only at the Räpu (p < 0.001) and Jänijõgi (p < 0.05) catchments (one-sided test). After conditioning on trends in water discharge there was only one (Räpu) statistically significant temporal upward trend in TN loss. Elevated nitrogen concentrations in three other catchments (Rägina, Vodja, Porijõgi) explain only part of the upward trend in nitrogen losses and increasing tendencies in losses could mainly be associated with upward tendency in discharge. The direct (not flow-normalised) unit-area loss of nitrogen from agricultural land reached to 63.1 and 82.5 kg N ha-1 yr-1 in the Räpu and Jänijõgi catchments, respectively, which is higher than seen at the Rägina basin (25 kg ha-1 yr-1) and the River Vodja catchment (21.9 kg ha-1 yr-1). Elevated losses are typical for recent years, particularly after 2007. © 2014 Elsevier B.V. All rights reserved.
Sluzenikina J.,Estonian Environment Agency |
Mannik A.,Estonian Environment Agency
Proceedings of the Estonian Academy of Sciences | Year: 2016
The impact of the Advanced Scatterometer (ASCAT) data assimilation on the quality of HIRLAM analysis is assessed in cases of rapidly developing severe storms of 2013. The HIRLAM quality is analysed for two observing system experiments: with and without the ASCAT data assimilation. Mainly impact on the model analysis output is evaluated. Marine observations of 10-m wind speed and mean sea level pressure are used as measures of quality. The results show that depending on ASCAT data coverage in the HIRLAM domain and temporal availability of the data at the assimilation time moment, the impact may be either more or less accurate. It is also detected that some narrow places of the Baltic Sea (Bothnian Bay, Gulf of Finland) are not affected by the ASCAT data assimilation. According to the ASCAT Wind Product specification, ASCAT measurements near the shoreline are usually flagged as land contaminated. The ASCAT winds in these areas are not admitted to the analysis after the procedure of the HIRLAM quality control, most likely due to the proximity to the land. The use of the ASCAT Coastal Wind Product in the future may enlarge the ASCAT data coverage in these areas. In addition, some weaknesses of the ASCAT data assimilation were detected in the study raising the question of the optimal ASCAT data usage. Further attempts to improve the quality of the HIRLAM analyses are expected in the ASCAT data thinning before assimilation or by reducing time differences between the HIRLAM analyses. © 2016 Authors.
Russak V.,Tartu Observatory |
Niklus I.,Estonian Environment Agency
Proceedings of the Estonian Academy of Sciences | Year: 2015
Solar radiation has been continuously measured in Estonia since 1950, but the recordings of longwave radiation began only about ten years ago. This paper presents the first description of the characteristic features of up- and downwelling longwave radiation in the Baltic Sea region. In the radiation balance the longwave fluxes have an important role. In the annual totals of radiation incident upon the ground surface in Estonia, the longwave atmospheric downwelling radiation L1↓ exceeds the direct solar radiation Eg↓ about three times, and this ratio has an essential seasonal run. In the total upwelling radiation L1↑, the infrared part is still greater, up to 92%. Comparing the measured and calculated (according to the Stefan–Boltzmann law) hourly totals of L1↑ for snow (emissivity ε = 0.85) we found a good linear relationship (R2 = 0.96). However, the measured totals systematically exceeded the calculated values (on average by 18%). Dependence of the downwelling infrared radiation L1↓ on the near-surface water vapour pressure e is approximated by a power function (R2 = 0.73). This is in good accordance with the results of studies carried out at other geographical sites. The influence of clouds on the fitted power function is noteworthy. Separate analysis of the hours with full cloudiness of low clouds and the cloudless hours confirmed the validity of the power function. However, a difference was found in their parameters (for overcast sky the exponent b = 0.20, R2 = 0.91 and for cloudless sky b = 0.25 and R2 = 0.93). © 2015, Estonian Academy Publishers. All rights reserved.
Vali U.,Estonian University of Life Sciences |
Vainu O.,Estonian Environment Agency
Ringing and Migration | Year: 2015
The Common Buzzard Buteo buteo is a widespread species whose migration pattern differs by subspecies and regionally. Ring recoveries indicated that Buzzards originating from Estonia move southwest and winter in central and western Europe. This suggests that Estonia is occupied by the nominate subspecies of the Common Buzzard, which is a short-distance migrant. © 2016 British Trust for Ornithology.