scholarly journals Changes of weather conditions in Ukraine under climate changes

2017 ◽  
pp. 31-37
Author(s):  
V.M. Khokhlov ◽  
H.O. Borovska ◽  
O.V. Umanska ◽  
M.S. Tenetko
Keyword(s):  
Wavelet Analysis ◽  
North Atlantic ◽  
Climate Changes ◽  
Global Climate ◽  
Weather Conditions ◽  
Global Climate Changes ◽  
The North ◽  
Regional Feature ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

The paper analyzes spatiotemporal features the indices of hot, cold and precipitation that are related to weather conditions. The temperature in Ukraine tends to be higher, which is the main regional feature of global climate changes. The North Atlantic Oscillation had an influence on the precipitation in Ukraine – weather is rainier during its negative phases. Also, colder night and hotter days were more frequent during negative phases of the NAO. This fact can be explained by enhancing meridional flows in Ukraine. The wavelet analysis also revealed an impact of the NAO on temperature anomalies – positive phases determined increasing monthly minimum temperatures before the 1980s and decreasing ones after 1980s. Also, the wavelet analysis showed that the Nor-th Atlantic Oscillation influenced the precipitation in northern and southern parts of Ukraine in different ways.

scholarly journals Monitoring and interpreting the ocean uptake of atmospheric CO 2

2011 ◽  
Vol 369 (1943) ◽  
pp. 1997-2008 ◽  
Author(s):  
Andrew J. Watson ◽  
Nicolas Metzl ◽  
Ute Schuster
Keyword(s):  
North Atlantic ◽  
Climate Changes ◽  
Global Climate ◽  
Climate Feedbacks ◽  
Global Climate Changes ◽  
The North ◽  
Indian Ocean Sector ◽  
The Indian Ocean ◽  
The North Atlantic ◽  
Ocean Sector

The oceans are an important sink for anthropogenically produced CO 2 , and on time scales longer than a century they will be the main repository for the CO 2 that humans are emitting. Our knowledge of how ocean uptake varies (regionally and temporally) and the processes that control it is currently observation-limited. Traditionally, and based on sparse observations and models at coarse resolution, ocean uptake has been thought to be relatively invariant. However, in the few places where we have enough observations to define the uptake over periods of many years or decades, it has been found to change substantially at basin scales, responding to indices of climate variability. We illustrate this for three well-studied regions: the equatorial Pacific, the Indian Ocean sector of the Southern Ocean, and the North Atlantic. A lesson to take from this is that ocean uptake is sensitive to climate (regionally, but presumably also globally). This reinforces the expectation that, as global climate changes in the future owing to human influences, ocean uptake of CO 2 will respond. To evaluate and give early warning of such carbon–climate feedbacks, it is important to track trends in both ocean and land sinks for CO 2 . Recent coordinated observational programmes have shown that, by organization of an observing network, the atmosphere–ocean flux of CO 2 can, in principle, be accurately tracked at seasonal or better resolution, over at least the Northern Hemisphere oceans. This would provide a valuable constraint on both the ocean and (by difference) land vegetation sinks for atmospheric CO 2 .

Rainfall Variability and Trend Analysis of Multiannual Rainfall in Romanian Plain

2017 ◽  
Vol 17 (2) ◽  
pp. 124-144 ◽  
Author(s):  
Zeineddine Nouaceur ◽  
Ovidiu Murărescu ◽  
George Murătoreanu
Keyword(s):  
North Atlantic Oscillation ◽  
Central Europe ◽  
North Atlantic ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
El Nino Southern Oscillation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

AbstractThe IPCC climate models predict, for the Central Europe, are for climate changes, being seen variability of temperature, with a growing trend of 1-2,5° C (with 1° C for alpine zone – Carpathians and 2-2,5° C for plains). Current observations in the Romanian plain are not consistent, with an existence of a multiannual variability of temperature and precipitations depending on cyclonal and anti-ciclonal activity. The research is based on calculation of reduced centered index, also the graphical chronological method in information processing (MGCTI) of „Bertin Matrix” type, to show current trends of the spatio-temporal variability of precipitation in the context of global climate change. These are in line with the movement of air masses in Europe in general, and implicitly in Romania, with particular regard to the southern region of the country where the Romanian Plain. The variability of short-term global climate is generally associated with coupling phases of oceanic and atmospheric phenomena including El Niño Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). While El Niño Southern Oscillation (ENSO) affects climate variability in the world, the North Atlantic Oscillation (NAO) is the climate model dominant in the North Atlantic region. The latter cyclic oscillation whose role is still under debate could explain the variability of rainfall in much of the, central Europe area, and support the hypothesis of a return of the rains marking the end of years of drought in Romanian plain. Faced with such great changes that today affect the central Europe region and given the complexity of spatial and temporal dimensions of the climatic signal, a more thorough research of causes and retroactions would allow for a better understanding of the mechanisms behind this new trend.

scholarly journals Nonlinear time series models for the North Atlantic Oscillation

2020 ◽  
Vol 6 (2) ◽  
pp. 141-157
Author(s):  
Thomas Önskog ◽  
Christian L. E. Franzke ◽  
Abdel Hannachi
Keyword(s):  
Time Series ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Nonlinear Models ◽  
Weather Conditions ◽  
Dominant Mode ◽  
Statistical Properties ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract. The North Atlantic Oscillation (NAO) is the dominant mode of climate variability over the North Atlantic basin and has a significant impact on seasonal climate and surface weather conditions. This is the result of complex and nonlinear interactions between many spatio-temporal scales. Here, the authors study a number of linear and nonlinear models for a station-based time series of the daily winter NAO index. It is found that nonlinear autoregressive models, including both short and long lags, perform excellently in reproducing the characteristic statistical properties of the NAO, such as skewness and fat tails of the distribution, and the different timescales of the two phases. As a spin-off of the modelling procedure, we can deduce that the interannual dependence of the NAO mostly affects the positive phase, and that timescales of 1 to 3 weeks are more dominant for the negative phase. Furthermore, the statistical properties of the model make it useful for the generation of realistic climate noise.

Nonlinear time series models for the North Atlantic Oscillation

2020 ◽  
Author(s):  
Abdel Hannachi ◽  
Thomas Önskog ◽  
Christian Franzke
Keyword(s):  
Time Series ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Nonlinear Models ◽  
Weather Conditions ◽  
Dominant Mode ◽  
Statistical Properties ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

<p>The North Atlantic Oscillation (NAO) is the dominant mode of climate variability over the North Atlantic basin and has a significant impact on seasonal climate and surface weather conditions. This is the result of complex and nonlinear interactions between many spatio-temporal scales. Here, the authors study a number of linear and nonlinear models for a station-based time series of the daily winter NAO index. It is found that nonlinear autoregressive models including both short and long lags perform excellently in reproducing the characteristic statistical properties of the NAO, such as skewness and fat tails of the distribution and the different time scales of the two phases. As a spinoff of the modelling procedure, we are able to deduce that the interannual dependence of the NAO mostly affects the positive phase and that timescales of one to three weeks are more dominant for the negative phase. The statistical properties of the model makes it useful for the generation of realistic climate noise.</p>

scholarly journals Influence of North Atlantic oscillation on Moscow climate continentality

2019 ◽  
Vol 55 (5) ◽  
pp. 32-38
Author(s):  
G. A. Alexandrov ◽  
A. S. Ginzburg ◽  
G. S. Golitsyn
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Global Climate ◽  
Carbon Dioxide Concentration ◽  
Climatic Conditions ◽  
Natural Variability ◽  
Oceanic Circulation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Natural variability of regional climatic conditions poses certain difficulties in detecting global climate change at a local scale. The question about the ratio between the contribution of human forcing, induced by the increase in atmospheric carbon dioxide concentration, and the contribution of natural variability in atmospheric and oceanic circulation arises in each particular case. The purpose of the study reported in this article was to evaluate the contribution of the North Atlantic Oscillation to decrease in Moscows climate continentality during the period of 1951-2000. The results of this study show that a significant part of the decrease in continentality could be attributed to increase in the North Atlantic Oscillation index observed during this period.

scholarly journals Wave Energy Extraction by the End of the Century: Impact of the North Atlantic Oscillation

2018 ◽  
Author(s):  
Jelena Janjić ◽  
Sarah Gallagher ◽  
Emily Gleeson ◽  
Frédéric Dias
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Large Scale ◽  
Global Climate ◽  
Wave Climate ◽  
Wavewatch Iii ◽  
The North ◽  
Wave Parameters ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Using wind speeds and sea ice fields from the EC-Earth global climate model to run the WAVEWATCH III model, we investigate the changes in the wave climate of the northeast Atlantic by the end of the 21st century. Changes in wave climate parameters are related to changes in wind forcing both locally and remotely. In particular, we are interested in the behavior of large-scale atmospheric oscillations and their influence on the wave climate of the North Atlantic Ocean. Knowing that the North Atlantic Oscillation (NAO) is related to large-scale atmospheric circulation, we carried out a correlation analysis of the NAO pattern using an ensemble of EC-Earth global climate simulations. These simulations include historical periods (1980–2009) and projected changes (2070–2099) by the end of the century under the RCP4.5 and RCP8.5 Representative Concentration Pathway (RCP) forcing scenarios with three members in each RCP wave model ensemble. In addition, we analysed the correlations between the NAO and a range of wave parameters that describe the wave climate from EC-Earth driven WAVEWATCH III model simulation over the North Atlantic basin, focusing on a high resolution two-way nested grid over the northeast Atlantic. The results show a distinct decrease by the end of the century and a strong positive correlation with the NAO for all wave parameters observed.

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