scholarly journals Impact of the North Atlantic Oscillation on river runoff in the Belarus part of the Baltic Sea basin

2007 ◽  
Vol 38 (4-5) ◽  
pp. 413-423 ◽  
Author(s):  
I. Danilovich ◽  
D. Wrzesiński ◽  
L. Nekrasova

The dynamics of the North Atlantic Oscillation (NAO) and river runoff in the Belarus part of the Baltic Sea basin have been studied. Correlation coefficients between NAO indices and monthly, seasonal and annual discharges were calculated, changes in the runoff in the opposite stages of NAO and its intra-annual distribution were analysed, and runoff trends for different time series were investigated. The closest connection could be observed between NAO indices for December–March and the runoff of Belarusian rivers in the Baltic basin. The highest correlation coefficients were calculated for winter and spring months. The intra-annual runoff differs in opposite stages of the North Atlantic Oscillation. The most significant increase of monthly runoff was observed after 1961. There was a positive trend of runoff at the beginning of the year, but a negative one in the summer and autumn months.

2002 ◽  
Vol 33 (4) ◽  
pp. 319-330 ◽  
Author(s):  
Svetlana Jevrejeva

Variations in time series of sum of negative degree-days, number of days with ice, date of ice break-up and maximum ice thickness on the Baltic Sea along the Estonian coast have been examined within context of the atmospheric circulation above the North Atlantic. It was found out that 20 – 50 % of ice conditions along the Estonian coast might be explained by the state of the NAO winter index. However, correlation coefficients between time series of ice conditions and the NAO winter index varies with time; moving correlation coefficient can reach -0.98.


2008 ◽  
Vol 21 (3) ◽  
pp. 532-541 ◽  
Author(s):  
Frank A. Aebly ◽  
Qi Hu ◽  
Sherilyn C. Fritz

Abstract Observed precipitation records from Kangerlussuaq, Greenland, and atmospheric variables from the NCEP–NCAR reanalysis were used in a statistical analysis to elucidate controls on the seasonal variation of precipitation and develop indices that may be potentially useful for analyzing precipitation variability in paleoclimate and future climate change investigations. Three distinct patterns of correlation between precipitation and the 500-hPa geopotential height were found to represent three dominant atmospheric patterns that strongly influence precipitation for different times of the year. All three patterns show a relation to the North Atlantic Oscillation signature found in the first empirical orthogonal function of the 500-hPa height field. Spatially dependent indices were developed based on the 500-hPa geopotential field. The correlation coefficients between precipitation at Kangerlussuaq and these indices range from −0.38 for winter to 0.64 for the warm season (May–September). The warm-season index herein is the first index reported in the literature that correlates significantly with precipitation during the warm season. Correlations of these indices with precipitation in Oslo, Norway, are high and are of opposite sign to west Greenland indices for the winter and summer months. This indicates that they are good representations of the atmospheric patterns associated with the North Atlantic Oscillation and the west Greenland–northern Europe “seesaw.” High correlations are also found with precipitation measured at Nuuk, Qaqortoq, and Upernavik, Greenland.


2019 ◽  
Vol 323 (2) ◽  
pp. 127-135
Author(s):  
V.A. Petukhov ◽  
A.O. Smurov

The life cycle of nematode Paramononchus alimovi Tsalolichin on two deepwater stations (St. 2 and St. 18) in Lake Krivoe and the contribution of the long-term climate variability to the dynamics of the quantitative development of this species were investigated. As a result of the research, it was shown that the life cycle of this species in Lake Krivoe is 2–3 months. The temperature conditions of this species existence are stable and close to the temperature optimum for this species. Climatic factors indirectly influence the quantitative development of this species in Lake Krivoe. To analyze the influence of climate on the dynamics of quantitative development of P. alimovi, we calculated the correlation coefficients of the relationship between the average seasonal (May-September) nematode abundance and biomass and indices of the North-Atlantic Oscillation (NAO), arctic oscillation (AO). We found a significant effect of the North Atlantic Oscillation on the quantitative development of nematodes at St.2 for the period July-September (NAO_JAS) with a lag of 2 years, for the period December – March (NAO_DJFM) with a lag of 1 year. For St. 18 a reliable relationship of quantitative development of nematodes with the index for the period March-May (NAO_MAM) without lag is shown. Correlations of climatic indices with benthic biomass with a lag of 1 year and without lag are characteristic of many northern lakes. The maximum income of nutrients should be observed after complete thawing of soils and should be confined to autumn floods. Thus, years with positive index anomalies provide favorable opportunities for the development of phytoplankton in the next year, which is indirectly reflected in the zoobenthos through the trophic chain. Correlation of the NAO index with the values of quantitative development of nematodes in current year is related to the weather preceding the ice disappearance on the lake. Explanation of the obtained two-year lag is associated with another component of the ecosystem – macrozoobenthos. The main component of macrozoobenthos in the depths of the Lake Krivoe is amphipod Monoporeia affinis. This species has 2-year cycle and competes for resources with P. alimovi.


2013 ◽  
Vol 21 (4) ◽  
pp. 38-49 ◽  
Author(s):  
Labudová Lívia ◽  
Pavel Šťastný ◽  
Milan Trizna

Abstract The North Atlantic Oscillation (NAO) is the most important circulation phenomenon in the Northern Atlantic which impacts climate in Europe in various ways. Precipitation is a basic climatic element which affects the landscape significantly. Therefore in this paper, the relationship between the NAO and winter precipitation in Slovakia is analysed. A Spearman’s correlation analysis was used, which detected the impacts of NAO on the above-mentioned seasonal precipitation in different regions of Slovakia. The correlation coefficients obtained positive values in the region of Orava and Kysuce and changed to negative ones in a southward direction. The detected zonal configuration can be explained by the topographic barrier effect of the Carpathians


2021 ◽  
Author(s):  
Pedro Jiménez-Guerrero ◽  
Nuno Ratola

AbstractThe atmospheric concentration of persistent organic pollutants (and of polycyclic aromatic hydrocarbons, PAHs, in particular) is closely related to climate change and climatic fluctuations, which are likely to influence contaminant’s transport pathways and transfer processes. Predicting how climate variability alters PAHs concentrations in the atmosphere still poses an exceptional challenge. In this sense, the main objective of this contribution is to assess the relationship between the North Atlantic Oscillation (NAO) index and the mean concentration of benzo[a]pyrene (BaP, the most studied PAH congener) in a domain covering Europe, with an emphasis on the effect of regional-scale processes. A numerical simulation for a present climate period of 30 years was performed using a regional chemistry transport model with a 25 km spatial resolution (horizontal), higher than those commonly applied. The results show an important seasonal behaviour, with a remarkable spatial pattern of difference between the north and the south of the domain. In winter, higher BaP ground levels are found during the NAO+ phase for the Mediterranean basin, while the spatial pattern of this feature (higher BaP levels during NAO+ phases) moves northwards in summer. These results show deviations up to and sometimes over 100% in the BaP mean concentrations, but statistically significant signals (p<0.1) of lower changes (20–40% variations in the signal) are found for the north of the domain in winter and for the south in summer.


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