scholarly journals Axial variability in the relationship of chlorophyll a with climatic factors and the North Atlantic Oscillation in a Basque coast estuary, Bay of Biscay (1997-2006)

2008 ◽  
Vol 30 (9) ◽  
pp. 1041-1049 ◽  
Author(s):  
F. Villate ◽  
G. Aravena ◽  
A. Iriarte ◽  
I. Uriarte
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Climatic Factors ◽  
Bay Of Biscay ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Relationship Of ◽  
Basque Coast ◽  
The Relationship

The Relationship between the North Atlantic Oscillation and High-Wind Observations Across the Eastern United States 

2021 ◽  
Author(s):  
Sylvia Stinnett ◽  
Joshua Durkee ◽  
Joshua Gilliland ◽  
Victoria Murley ◽  
Alan Black ◽  
...  
Keyword(s):  
United States ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Eastern United States ◽  
High Wind ◽  
The North ◽  
The North Atlantic ◽  
Wind Events ◽  
The North Atlantic Oscillation ◽  
The Relationship

<p>The North Atlantic Oscillation (NAO) is a high-frequency oscillation that has known influences on the climatology of weather patterns across the eastern United States. This study explores the relationship between the daily North Atlantic Oscillation index with observed high-wind events from 391 first-order weather stations across the eastern U.S. from 1973-2015. These events were determined following typical National Weather Service high-wind criteria: sustained winds of at least 18 m•s-1 for at least 1 hour or a wind gust of at least 26 m•s-1 for any duration. Since research literature shows high-wind events are often connected to parent mid-latitude cyclone tracks, and since the NAO has been shown to influence these storm tracks, it is hypothesized that changes in NAO phases are connected to spatial shifts and frequencies in high-wind observations. Initial results show a preferred southwesterly direction during each NAO phase. Variance in high-wind directions appears to increase (decrease) during negative (positive) NAO phases. Further, the greatest spatial difference in the mean center of high-wind observations was between positive and negative NAO phases. Overall, these preliminary findings indicate changes in high-wind observations may be linked to NAO phases.</p>

Mapping Wet-Dry Signatures of the North Atlantic Oscillation (NAO) in British Catchments

2020 ◽  
Author(s):  
Harry West ◽  
Nevil Quinn ◽  
Michael Horswell
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Temporal Analysis ◽  
Precipitation Patterns ◽  
The North ◽  
Standardised Precipitation Index ◽  
The North Atlantic ◽  
Spatio Temporal ◽  
The North Atlantic Oscillation ◽  
The Relationship

<p>The North Atlantic Oscillation (NAO) is one of the primary atmospheric circulations which influence weather patterns in Great Britain. Its two phases (either positive or negative depending on differences in sea level pressure) result in characteristic precipitation patterns, the effects of which cascade down to signatures in streamflow. However, in relation to streamflow response to the NAO, these studies have been spatio-temporally limited as they have been undertaken using a small number of measurement sites with relatively short records.</p><p>The release of new historic datasets from the UK Centre for Ecology and Hydrology (CEH) provides a new opportunity to undertake a broad spatio-temporal analysis of the relationship between NAO and streamflow. This research used reconstructed daily flows for 291 catchments and the associated Standardised Streamflow Index (SSI) to explore the relationship between the North Atlantic Oscillation Index (NAOI) for the period January 1900-November 2015. Spearman correlations were calculated at monthly intervals between the NAOI and SSI (with a 1-month accumulation period), and the historic flows dataset was used to explore the variability in flows across the catchments under NAO+ and NAO- phases.</p><p>This analysis revealed distinct wet and dry spatio-temporal signatures in streamflow. The winter months are characterised by a north-west and south-east divide in this relationship; catchments in the northern and western regions show strong positive correlations between the NAOI and SSI and NAO+ is associated with higher than normal flows in many north-western catchments, and vice versa under NAO-. While catchments in the south-eastern and central regions are negatively correlated and therefore show and opposite wet-dry response. However, during the summer months, while there are some wet-dry signatures under NAO positive/negative phases - the reverse to that seen in winter, almost all catchments show weak NAOI-SSI negative correlation values. </p><p>Finally, we compare the wet-dry responses to the NAO observed in streamflow to NAO-precipitation patterns, measured via correlations between the NAOI and Standardised Precipitation Index with a 1-month accumulation period over the same study period. The two sets of correlations (NAO-SPI and NAO-SSI) were analysed for spatio-temporal similarity through a Geographically Weighted Regression (GWR) analysis and a space-time clustering analysis. This revealed that in winter, as described above, the correlations with SPI and SSI generally behave similarly during the winter months – i.e. the wet-dry signatures in rainfall cascade down and are identifiable in streamflow patterns. In the summer months the NAOI-SPI correlations for the majority of catchments are negative. In the NAOI-SSI correlations, the summer values, while still negative, are notably weaker. The catchments with the weakest NAOI-SSI correlations are those generally in the central/southern region. These catchments have very slow response times due to their characteristics which may moderate the NAO wet/dry rainfall deviation.</p>

scholarly journals Why is the North Atlantic Oscillation More Predictable in December?

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 477 ◽  
Author(s):  
Baoqiang Tian ◽  
Ke Fan
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Heat Fluxes ◽  
Surface Heat Fluxes ◽  
The North ◽  
Sea Surface Temperature Anomaly ◽  
Stratospheric Circulation ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Relationship

The prediction skill of the Climate Forecast System, version 2 (CFSv2), for the North Atlantic Oscillation (NAO) is evaluated in three winter months (December, January, and February). The results show that the CFSv2 model can skillfully predict the December NAO one month in advance. There are two main contributors to NAO predictability in December. One is the predictability of the relationship between the North Atlantic sea surface temperature anomaly (SSTA) tripole and the NAO and the other is the second empirical orthogonal function (EOF) mode of the geopotential height at 50 hPa (Z50-EOF2). The relationship between the NAO and SSTA tripole index in December is the most significant in the three winter months. The significant monthly differences of surface heat fluxes in December over the whole North Atlantic are favorable for promoting the interaction between the NAO and North Atlantic SSTAs, in addition to improving the predictability of the December NAO. When the NAO is in a positive phase, easterly anomalies are located at the low and high latitudes and westerly anomalies prevail in the mid-latitudes of the troposphere. The correlation between the December Z50-EOF2 and zonal-mean zonal wind anomalies shows a similar spatial structure to that for the NAO. The possible reason why the CFSv2 model can predict the December NAO one month ahead is that it can reasonably reproduce the relationship between the December NAO and both the North Atlantic SST and stratospheric circulation.

scholarly journals On the life cycle of Paramononchus alimovi Tsalolichin, 1990 and the influence of climatic factors on the quantitative development of this species in the Lake Krivoe

2019 ◽  
Vol 323 (2) ◽  
pp. 127-135
Author(s):  
V.A. Petukhov ◽  
A.O. Smurov
Keyword(s):  
Life Cycle ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Climatic Factors ◽  
Correlation Coefficients ◽  
Trophic Chain ◽  
The North ◽  
Quantitative Development ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

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.

Sign in / Sign up

Export Citation Format

Share Document