Understanding the influence of El Niño–Southern Oscillation (ENSO) on North Atlantic (NAO) is critical significance for seasonal prediction. The present study found that both Niño3.4 sea surface temperature anomaly (SSTA) intensity and east-west gradient in mid-low latitude Pacific determine linkage between ENSO NAO. Based SSTA gradient, events are classified into three types: strong intensity,...

This work is set out to quantify the contribution of tropical and extratropical atmospheric forcing mechanisms to the formation of the North Atlantic Oscillation (NAO) pattern. Although the NAO varies on a wide range of time scales, we focus on 10 60 d. At these time scales, mechanisms are at play in the atmosphere that can generate the characteristic dipole pattern. We focus on the tropical Ro...

1. The North Atlantic Oscillation (NAO) exerts considerable control on U.K. weather. This study investigates the impact of the NAO on butterfly abundance and phenology using 34 years of data from the U.K. Butterfly Monitoring Scheme (UKBMS).2. The study uses a multi-species indicator to show that the NAO does not affect overall U.K. butterfly population size. However, the abundance of bivoltine...

Temporal and spatial variability are analysed in Greenland instrumental temperature records from 24 coastal and three ice sheet locations. Trends over the longest period available, 1873–2001, at Ilulissat/Jakobshavn indicate statistically significant warming in all seasons: 5 °C in winter. Trends over the 1901–2000 century in southern Greenland indicate statistically significant spring and summ...

[1] Ice core-derived accumulation records from Greenland have been proposed as proxies for North Atlantic Oscillation (NAO) reconstruction. In a series of single-site analyses, accumulation records from ice cores drilled in western Greenland were found to exhibit the strongest linear association with NAO. In this paper, we expand on these findings by proposing a spatiotemporal statistical model...

Composite analyses, based on weekly snow-cover charts, temperature, sea level pressure, cyclone tracks and a rotated PCA of daily filtered 700 hPa geopotential height are used to examine relationships between the dominant modes of low-frequency atmospheric variability and mid-winter snow extent over the Eurasian continent. Two of the circulation modes examined have been identified previously an...

Carbon, water and energy exchanges between forests and the atmosphere depend upon seasonal dynamics of both temperature and precipitation, which are influenced by low frequency climate oscillations such as: El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Arctic Oscillation (AO), Eastern Pacific Oscillation (EPO) and the Pacific-North American (PNA). This study investigate...

We studied long-term trends and the yearly variation in mean spring passage time in 36 passerine bird species trapped at Ottenby Bird Observatory in south-eastern Sweden. Between the years 1952 /2002, data were available for 22 /45 years depending on species. Most long-distance migrant species passed progressively earlier over the study period (range: 2.5 days earlier to 0.7 days later per 10 y...

Studies of the impacts of climate and climate change on biological systems often attempt to correlate ecological responses with basin-scale indices such as the North Atlantic Oscillation (NAO). However, such correlations, while useful for detecting long-term trends, are unable to provide a mechanism linking the physical environment and ecological processes. Here we evaluate the effects of the N...

The ability of analysing atmospheric dynamics by idealized experiments using a simplified circulation model is illustrated in three related studies. The investigations focus on the organization of localized strom tracks, their impact on low-frequency variability, and on the response to external thermal forcing. A localized storm track in agreement with observations is forced by a heating dipole...