Statistical characterisation of winter precipitation in the Abruzzo region (Italy) in relation to the North Atlantic Oscillation (NAO)

2016 ◽  
Vol 178-179 ◽  
pp. 279-290 ◽  
Author(s):  
Lorenzo Vergni ◽  
Bruno Di Lena ◽  
Alessandro Chiaudani
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


2005 ◽  
Vol 5 (3) ◽  
pp. 331-344 ◽  
Author(s):  
J. L. Zêzere ◽  
R. M. Trigo ◽  
I. F. Trigo

Abstract. The aim of this study is to assess the impact of the North Atlantic Oscillation (NAO) on both the winter precipitation and the temporal occurrence of different landslide types in Portugal. The analysis is applied to five sample areas located just north of Lisbon, the capital of Portugal. These sites are particularly relevant because actual dates of most of the recent landslide events are known but also because the landslides occurred in a suburban area with growing urbanization pressure. Results show that the large inter-annual variability of winter precipitation observed in western Iberia, i.e. Portugal and parts of Spain, is largely modulated by the NAO mode. In particular, precipitation falling in Portugal between November and March presents a correlation coefficient of R=–0.66 with the NAO index. Precipitation distribution for the reference rain gauge in the study area reveals that the probability of a wet month to occur is much higher for low NAO index composites than for the corresponding high NAO index composite. It is shown that this control, exerted by NAO on the precipitation regime, is related to corresponding changes in the associated activity of North-Atlantic storm tracks that affect the western Iberia. Landslide activity in the study area is related to both intense, short duration precipitation events (1–15 days) and long-lasting rainfall episodes (1–3 months). The former events trigger shallow translational slides while the later episodes are usually associated with deeper and larger slope movements. This second group of landslides is shown to be statistically associated with the 3-month average of the NAO index.


2011 ◽  
Vol 15 (1) ◽  
pp. 57-64 ◽  
Author(s):  
G. Wang ◽  
A. J. Dolman ◽  
A. Alessandri

Abstract. Recent summer heat waves in Europe were found to be preceded by precipitation deficits in winter. Numerical studies suggest that these phenomena are dynamically linked by land-atmosphere interactions. However, there exists as yet no complete observational evidence that connects summer climate variability to winter precipitation and the relevant circulation patterns. In this paper, we investigate the functional responses of summer mean and maximum temperature (June–August, Tmean and Tmax) as well as soil moisture proxied by the self-calibrating Palmer drought severity index (scPDSI) to preceding winter precipitation (January–March, PJFM) for the period 1901–2005. All the analyzed summer fields show distinctive responses to PJFM over the Mediterranean. We estimate that 10 ~ 15% of the interannual variability of Tmax and Tmean over the Mediterranean is statistically forced by PJFM. For the scPDSI this amounts to 10 ~ 25%. Further analysis shows that these responses are highly correlated to the North Atlantic Oscillation (NAO) regime over the Mediterranean. We suggest that NAO modulates European summer temperature by controlling winter precipitation that initializes the moisture states that subsequently interact with temperature. This picture of relations between European summer climate and NAO as well as winter precipitation suggests potential for improved seasonal prediction of summer climate for particular extreme events.


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