scholarly journals The North Atlantic Oscillation signal in a regional climate simulation for the European region

2005 ◽  
Vol 57 (4) ◽  
pp. 641-653 ◽  
Author(s):  
Roxana Bojariu ◽  
Filippo Giorgi
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Regional Climate ◽  
European Region ◽  
Climate Simulation ◽  
Regional Climate Simulation ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Applying machine learning for drought prediction using a large ensemble of climate simulations

2021 ◽  
Author(s):  
Elizaveta Felsche ◽  
Ralf Ludwig
Keyword(s):  
Machine Learning ◽  
Regional Climate Model ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
North Atlantic Oscillation Index ◽  
Climate Model ◽  
Regional Climate ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

<p>There is strong scientific and social interest to understand the factors leading to extreme events in order to improve the management of risks associated with hazards like droughts. Recent events like the summer 2018 drought in Germany already had severe und unexpected impacts, e.g. forest fires and crop failures; in order to increase preparedness robust prediction tools are  urgently required. In this study, machine learning methods are applied to predict the occurrence of a drought with lead times of one to three months. The approach takes into account a list of thirty atmospheric and soil variables<strong> </strong>as predictor input parameters from a single regional climate model initial condition large ensemble (CRCM5-LE). The data was produced the context of the ClimEx project by Ouranos with the Canadian Regional Climate Model (CRCM5) driven by 50 members of the Canadian Earth System Model (CanESM2) for the Bavarian and Quebec domains.</p><p>Drought occurrence was defined using the Standardized Precipitation Index. The training and test datasets were chosen from the current climatology (1955-2005) for the Munich and Lisbon subdomain within the CRCM5-LE. The best performing machine learning algorithms managed to obtain a correct classification of drought or no drought for a lead time of one month for around 60 % of the events of each class for the both domains. Explainable AI methods like feature importance and shapley values were applied to gain a better understanding of the trained algorithms. Physical variables like the North Atlantic Oscillation Index and air pressure one month before the event proved to be of high importance for the prediction. The study showed that better accuracies can be obtained for the Lisbon domain, due to the stronger influence of the North Atlantic Oscillation Index on Portugal’s climate.</p>

scholarly journals Effect of large-scale modes of total variability of the atmosphere and ocean in the Atlantic-European region on the climate of Belarus

2020 ◽  
Vol 64 (5) ◽  
pp. 609-616
Author(s):  
S. A. Lysenko ◽  
V. F. Loginov ◽  
I. V. Buyakov
Keyword(s):  
North Atlantic Oscillation ◽  
Air Temperature ◽  
North Atlantic ◽  
Large Scale ◽  
European Region ◽  
The North ◽  
Temperature And Precipitation ◽  
Acceleration And Deceleration ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

We have established the relationships of quasicyclic components in changes of air temperature and precipitation in Belarus with large-scale modes of general variability of the atmosphere and ocean in the Atlantic-European region. When the summer air temperature changes in Belarus and in Eastern Europe, a quasi-60-year oscillation is identified, which coincides in phase with the Atlantic multi-decadal oscillation. It is shown that the time series of winter air temperature in Belarus contain a quasi-8-year component synchronized with a similar component of the North Atlantic Oscillation. Moreover, the periods of acceleration and deceleration of winter warming in Belarus coincide with the upward and downward quasi-30-year phases of the North Atlantic Oscillation, respectively. The latter are also consistent with fluctuations in moisture content in Belarus and Europe. Based on the established patterns, we have concluded that the rapid rise in winter temperatures, slowing down of summer warming and deterioration in water supply in the southern regions of Belarus observed in the last decade are part of a natural cycle lasting about 30 years, developing against the background of a long-term trend of anthropogenic global warming. 

scholarly journals Influence of the North Atlantic oscillation on the atmospheric levels of benzo[a]pyrene over Europe

2021 ◽  
Author(s):  
Pedro Jiménez-Guerrero ◽  
Nuno Ratola
Keyword(s):  
Spatial Pattern ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Transport Model ◽  
Regional Scale ◽  
The South ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

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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