scholarly journals Links between Teleconnection Patterns and Water Level Regime of Selected Polish Lakes

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1330 ◽  
Author(s):  
Katarzyna Plewa ◽  
Adam Perz ◽  
Dariusz Wrzesiński
Keyword(s):  
North Atlantic ◽  
Lake Water ◽  
Correlation Coefficients ◽  
Water Levels ◽  
Winter Period ◽  
East Atlantic ◽  
Teleconnection Patterns ◽  
Hierarchical Grouping ◽  
Level Regime ◽  
Circulation Indices

The paper identifies relationships between lake water levels and indices of macroscale atmospheric circulations: Arctic Oscillation (AO), North Atlantic Oscillation (NAO), East Atlantic (EA), and Scandinavian pattern (SCAND). Correlation coefficients between synchronous and asynchronous series of monthly water levels and 4 circulation indices were calculated. Based on Ward hierarchical grouping considering 156 correlation coefficients, the groups of lakes were designated due to the strength and term of relation of circulation indices with lake water levels. It was found that these links are not strong but noticeable. The strength of relationships varies in space and time, and the designated groups of lakes refer not only to the climatic diversity of the studied area, but also to some extent to the types of water levels regime. The observed relationships are the most important in the case of AO and NAO (particularly in winter period), and slightly weaker for EA and SCAND. The analysis used mean monthly water levels of 15 lakes in northern Poland from 1976–2015.

scholarly journals Exploring Combined Influences of Seasonal East Atlantic (EA) and North Atlantic Oscillation (Nao) on the Temperature-Precipitation Relationship in the Iberian Peninsula

2021 ◽  
Author(s):  
Fernando S. Rodrigo
Keyword(s):  
North Atlantic Oscillation ◽  
Iberian Peninsula ◽  
North Atlantic ◽  
Negative Relationship ◽  
Correlation Coefficients ◽  
East Atlantic ◽  
Teleconnection Patterns ◽  
The North ◽  
Spatial Coverage ◽  
The North Atlantic Oscillation

The combined influence of the North Atlantic Oscillation (NAO) and the East Atlantic (EA) patterns on the covariability of temperatures and precipitation in 35 stations of the Iberian Peninsula during the period 1950-2019 is analysed in this work. Four EA-NAO composites were defined from teleconnection patterns positive and negative phases: EA+NAO+, EA+NAO-, EA-NAO+, and EA-NAO-. Daily data of maximum and minimum temperature were used to obtain seasonal means (TX, and TN, respectively), and the covariability of these variables with accumulated seasonal rainfall (R) was studied comparing results obtained for different NAO and EA composites. Main results indicate slight differences in the spatial coverage of correlation coefficients between R and temperature variables, except in spring when the generalized negative relationship between R and TX under EA+NAO+ and EA-NAO- disappears under EA-NAO+ and EA+NAO- composites. This result may be useful to interpret and discuss historical reconstructions of Iberian climate.

scholarly journals Exploring Combined Influences of Seasonal East Atlantic (EA) and North Atlantic Oscillation (NAO) on the Temperature-Precipitation Relationship in the Iberian Peninsula

Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 211
Author(s):  
Fernando S. Rodrigo
Keyword(s):  
North Atlantic Oscillation ◽  
Iberian Peninsula ◽  
North Atlantic ◽  
Negative Relationship ◽  
Correlation Coefficients ◽  
East Atlantic ◽  
Teleconnection Patterns ◽  
The North ◽  
Spatial Coverage ◽  
The North Atlantic Oscillation

The combined influence of the North Atlantic Oscillation (NAO) and the East Atlantic (EA) patterns on the covariability of temperatures and precipitation in 35 stations of the Iberian Peninsula during the period 1950–2019 is analysed in this work. Four EA-NAO composites were defined from teleconnection patterns’ positive and negative phases: EA+NAO+, EA+NAO-, EA-NAO+ and EA-NAO-. Daily data of maximum and minimum temperature were used to obtain seasonal means (TX and TN, respectively), and the covariability of these variables with accumulated seasonal rainfall (R) was studied comparing results obtained for different NAO and EA composites. Main results indicate slight differences in the spatial coverage of correlation coefficients between R and temperature variables, except in spring when the generalised negative relationship between R and TX under EA+NAO+ and EA-NAO- disappears under EA-NAO+ and EA+NAO- composites. This result may be useful to interpret and discuss historical reconstructions of the Iberian climate.

Long-term predictability of winter teleconnection indices and their relationship to seasonal temperature extremes in Europe

2021 ◽  
Author(s):  
Nina Schuhen ◽  
Nathalie Schaller ◽  
Hannah C. Bloomfield ◽  
David J. Brayshaw ◽  
Jana Sillmann ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Surface Temperature ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Decadal Variability ◽  
Environmental Research ◽  
Seasonal Temperature ◽  
East Atlantic ◽  
Teleconnection Patterns

<p>European winter weather is dominated by several low-frequency teleconnection patterns, the main ones being the North Atlantic Oscillation (NAO), East Atlantic, East Atlantic/Western Russia and Scandinavian patterns. Through predicting these patterns, skillful forecasts of weather parameters like surface temperature can be generated, which in turn are used in a variety of applications (e.g., predictions of energy demand). A previous study (Weisheimer et.al., 2017) found that the NAO was subject to decadal variability during the twentieth century, affecting its long-term predictability. During recent decades, predictions for the NAO index have shown considerable skill, but this is likely to change during future periods of reduced predictability.</p><p>We analyze the century-long ERA-20C reanalysis and ASF-20C seasonal hindcast datasets to find if the other main teleconnection patterns also experience fluctuations in predictability, with potential implications for future skill and development of seasonal forecasting models. By linking the teleconnections to extreme cold and heat wave indices (Russo et al., 2015), we highlight the impact of these large-scale patterns on seasonal surface temperature in Europe during two periods of interest in the middle and end of the century. Our study shows that even though the predictability of the teleconnection patterns themselves fluctuates on a decadal scale, the links to winter surface temperatures are not significantly affected. However, the ability of the seasonal hindcasts to reproduce these patterns is quite limited.</p><p> </p><p>References:</p><p>Russo, S., Sillmann, J., & Fischer, E. M. (2015). Top ten European heatwaves since 1950 and their occurrence in the coming decades. Environmental Research Letters, 10(12), 124003. doi: 10.1088/1748-9326/10/12/124003</p><p>Weisheimer, A., Schaller, N., O’Reilly, C., MacLeod, D. A., & Palmer, T. (2017). Atmospheric seasonal forecasts of the twentieth century:  multi-decadal variability in predictive skill of the winter North Atlantic Oscillation (NAO) and their potential value for extreme event attribution. Quarterly Journal of the Royal Meteorological Society, 143(703), 917-926. doi: 10.1002/qj.29</p>

scholarly journals Winter Cyclone Regimes Over The North Atlantic

2021 ◽  
Author(s):  
Veronika N. Maslova ◽  
Elena N. Voskresenskaya ◽  
Alexander V. Yurovsky ◽  
Mikhail Yu. Bardin
Keyword(s):  
North Atlantic ◽  
Reanalysis Data ◽  
East Atlantic ◽  
Teleconnection Patterns ◽  
The Third ◽  
The North ◽  
Function Decomposition ◽  
Spectral Peaks ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract To study regimes of winter cyclones in the North Atlantic, empirical orthogonal function decomposition was applied separately to the frequency, depth and area of cyclones obtained using 6-hourly NCEP/NCAR reanalysis data in 1952–2017 and the developed methodology. The first mode represented the opposite changes of cyclone anomalies in the northern and southern/central North Atlantic. The second mode was characterized by the greatest regional anomalies between its phases over Europe, off its coast and over the Mediterranean. The greatest changes of anomalies for the third modes were in temperate latitudes, both over the ocean and Europe. Linear trends were significant only for the first modes of cyclone parameters. The largest part of variability (74–90% of dispersion) of all cyclone modes corresponded to the periods up to 15 years and was used for spectral analysis, which identified significant spectral peaks: 2.5–3, 4.5, 6 and 8.5 years. These periods coincided with spectral peaks of the main interannual climate signals. Regression analysis allowed to identify the sets of teleconnection patterns responsible jointly for 60–85% of dispersion of the first cyclone modes. The North Atlantic Oscillation and Arctic Oscillation were the main patterns for the first modes of the cyclone parameters. For the second and third frequency modes, the East Atlantic (EA) pattern and a combination of the East Atlantic/West Russia (EA/WR) and Scandinavia patterns played the major role, respectively. As for the third depth and area modes, the association with the EA and EA/WR patterns was shown, respectively.

scholarly journals The influence of large-scale climatic patterns on precipitation, temperature, and discharge in Czech river basins

2013 ◽  
Vol 61 (4) ◽  
pp. 278-285 ◽  
Author(s):  
Václav Šípek
Keyword(s):  
River Basin ◽  
Lead Time ◽  
Large Scale ◽  
Correlation Coefficients ◽  
Late Summer ◽  
River Basins ◽  
Winter Period ◽  
Sea Level Pressure ◽  
Precipitation Temperature ◽  
Teleconnection Patterns

Abstract The present study focuses on the possible influence of large-scale climatic patterns on precipitation, temperature, and discharge in two distinct river basins in the Czech Republic. The first one is a flat lowland basin of the Cidlina River and the second one represents a more mountainous type of climate (the Blanice River). The large-scale climatic patterns used comprise monthly averages of teleconnection patterns, sea level pressure values, and two geopotential heights (850 hPa and 500 hPa). The correlations for corresponding months and also up to a three months lead time were investigated. The relations concerning the corresponding months proved to be most reliable in the winter period of the year. The behaviour of both selected river basins with respect to these predictors is rather similar in character. However, higher values of correlation coefficients are reached in the case of the Cidlina River basin. Considering the prediction abilities with a certain lead time, the results seem to be more promising for the winter and spring periods in both basins. In the Cidlina River basin, they are likely to be beneficial also for the late summer and autumn period.

scholarly journals Cold Winter Over North America: The Influence of the East Atlantic (EA) and the Tropical/Northern Hemisphere (TNH) Teleconnection Patterns

2016 ◽  
Vol 10 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Masayo Ogi ◽  
Søren Rysgaard ◽  
David G. Barber
Keyword(s):  
North America ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Pacific ◽  
Cold Winter ◽  
East Atlantic ◽  
Teleconnection Patterns ◽  
The North ◽  
The North Pacific ◽  
Sst Anomalies

Anomalous cold temperatures and strong cyclonic circulation were observed during winter 2013/14 over North America. In this article, we propose for the first time that positive East Atlantic (EA) and positive Tropical/Northern Hemisphere (TNH) patterns were dominant in the winter of 2013/14. The values of the EA and TNH indices for winter 2013/14 were the highest and the second highest for the period of record 1951-2014, respectively. The combined EA and TNH pattern is similar to the corresponding atmospheric circulation observed in the winter of 2013/14. The regression patterns of air temperatures on the EA and TNH index show negative anomalies over North America and the North Atlantic Ocean and positive anomalies over the North Pacific Ocean and the mid-latitude Atlantic Ocean. The regression pattern is similar to air temperature anomalies in winter 2013/14. In addition, the combined EA and TNH pattern correlates with sea surface temperature (SST) anomalies over the North Pacific and North Atlantic that are similar to the winter SST anomalies in winter 2013/14. The EA and TNH teleconnection patterns have contributed to the anomalous atmospheric circulation associated with the extreme cold winter over North America in 2013/14.

scholarly journals Assessing the Skills of a Seasonal Forecast of Chlorophyll in the Global Pelagic Oceans

2021 ◽  
Vol 13 (6) ◽  
pp. 1051
Author(s):  
Cecile S. Rousseaux ◽  
Watson W. Gregg ◽  
Lesley Ott
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Chlorophyll Concentration ◽  
Correlation Coefficients ◽  
Global Scale ◽  
Seasonal Forecasts ◽  
Mean Square Errors ◽  
Satellite Chlorophyll

While forecasts of atmospheric variables, and to a lesser degree ocean circulation, are relatively common, the forecast of biogeochemical conditions is still in its infancy. Using a dynamical ocean biogeochemical forecast forced by seasonal forecasts of atmospheric and physical ocean variables, we produce seasonal predictions of chlorophyll concentration at the global scale. Results show significant Anomaly Correlation Coefficients (ACCs) for the majority of regions (11 out of the 12 regions for the 1-month lead forecast). Root mean square errors are smaller (<0.05 µg chlorophyll (chl) L−1) in the Equatorial regions compared to the higher latitudes (range from 0.05 up to 0.13 µg chl L−1). The forecast for all regions except three (North Atlantic, South Pacific and North Indian) are within the Semi-Interquartile Range of the satellite chlorophyll concentration (Suomi-National Polar-orbiting Partnership (NPP), 27.9%). This suggests the potential for skillful global biogeochemical forecasts on seasonal timescales of chlorophyll, primary production and harmful algal blooms that could support fisheries management and other applications.

ZABOLOTSKA T.M., SHPYG V.M., TSILA A.YU. CIRCULATION INDEXES AND THE CLOUD COVER DURING OF THE GLOBAL WARMING PERIOD

2021 ◽  
pp. 76-91
Author(s):  
T.M. Zabolotska ◽  
V.M. Shpyg ◽  
A.Yu. Tsila
Keyword(s):  
Global Warming ◽  
North Atlantic ◽  
Relative Frequency ◽  
Cloud Cover ◽  
Annual Data ◽  
East Atlantic ◽  
Clear Sky ◽  
The Difference ◽  
Monthly Variations ◽  
Overcast Sky

The investigations of connection between the different meteorological processes, for example, the circulation indexes with the quantity of the total and lower cloudiness during 1961-2018 over Ukraine were made. The spatial distributions of the total and lower cloudiness were received for 73 years (1946-2018) at first. The quantity of cloudiness is diminished from west to east and with north to south. The declinations of the annual data of total and lower cloudiness from the historical (1961-1990) and the present (1981-2010) norms were calculated. The great variations were characterized for the lower cloudiness. The linear trends showed that the diminish of the lower cloudiness was on 90 % of the all territory, this changes were important on 70 % of the territory. The trends of the monthly variations were showed on the diminish of the lower cloudiness in during all year only on north, on other territory was the increasing in the separate months, frequently in January and September. The variations of the total cloudiness were insignificant, the increase or decrease were nearly in equal parts. North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East-Atlantic Oscillation (EA), Scandinavian Oscillation (SCAND), Greenlandic Oscillation (GBI) and South Oscillation (El-Niño) were used for the investigation of relationship between the circulation indexes and cloud cover. It was shown that different circulation indexes have influence on climate of Northern Hemisphere and on Ukraine too. The relation with each other and their variations in period of global warming were showed. The quantity estimation of the total and lower cloudiness variations was made by the frequencies of clear, semi clear and overcast sky in the successive decades and by the relative variations of frequencies between decades (1961-1970 and 1971-1980; 1971-1980 and 1981-1990; 1981-1990 and 1991-2000; 1991-2000 and 2001-2010; 2001-2010 and 2011-2018). The parallel analyze of the variations of circulation was estimated in that time. The difference between the circulating processes during 1961-1970 and 1971-1980 contributed to a decrease in the relative frequency of the clear sky (on 5.4%) and a slight increase of the overcast sky (on 1.6%) by total cloud cover and a slight increase of the clear sky (on 0.8 %) and a decrease of the overcast sky (on 5.2%) by lower cloudiness. At the same time, the relative frequency of the semi-clear sky by lower cloudiness almost in three times increased in comparison to total cloudiness (on 10.2% and 3.8%, respectively). In the third decade of 1981-1990 the relative frequency of clear sky by lower cloudiness increased on 5.1% and did not change by total cloudiness (0%). During this decade the relative frequency of overcast sky decreased the most in the whole period under study: by total cloudiness on 6.4% and by lower cloudiness on 13.3%. At the same time, the relative frequency of semi-clear sky had largest increasing: on 22.4% for total cloudiness and 13% for lower cloudiness. Then, during 1991-2000, the frequency of clear sky decreased significantly both for total cloudiness (on 6.5%) and for lower cloudiness (on 3.1%). The frequency of overcast sky decreased also, but less significantly (on 1.3% and 2.3%, respectively), thereby the number of clouds of the middle and upper levels increased. From 2001 to 2010, the frequency of clear sky by total cloudiness and by lower cloudiness continued to decrease (on 5.3 and 3.2%, respectively), but the frequency of overcast sky increased (on 0.9 and 1.7%, respectively), thereby the number of clouds for all levels increased. During 2011-2018 the frequency of clear sky by total cloudiness increased (on 0.9%) and by lower cloudiness did not change. The frequency of overcast sky decreased on 3.6% (by total cloudiness) and on 0.7% (by lower cloudiness). The variations of the relative frequencies of the different state sky between the successive decades are agreed with the changes of the circulation indexes.

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