North Atlantic Oscillation influences on Turkish lake levels

Küçük, Murat; Kahya, Ercan; Cengiz, Taner Mustafa; Karaca, Mehmet

doi:10.1002/hyp.7225

Cited by 51 publications

(24 citation statements)

References 34 publications

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“…(2010), periodicities of more than 10 years, more frequent in the northern region, are difficult to relate with the NAO. This was also concluded by Kücük et al (2009) for Turkey. Following the results reported by Tsiropoula (2003) and Hathaway (2010), these multidecadal cycles may relate to solar cycles.…”

Section: Discussionsupporting

confidence: 62%

Assessing drought cycles in SPI time series using a Fourier analysis

Moreira

Martins

Pereira

2015

Nat. Hazards Earth Syst. Sci.

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Abstract. In this study, drought in Portugal was assessed using 74 time series of Standardized Precipitation Index (SPI) with a 12-month timescale and 66 years length. A clustering analysis on the SPI Principal Components loadings was performed in order to find regions where SPI drought characteristics are similar. A Fourier analysis was then applied to the SPI time series considering one SPI value per year relative to every month. The analysis focused on the December SPI time series grouped in each of the three identified clusters to investigate the existence of cycles that could be related to the return periods of droughts. The most frequent significant cycles in each of the three clusters were identified and analysed for December and the other months. Results for December show that drought periodicities vary among the three clusters, pointing to a 6-year cycle across the country and a 9.4-year cycle in central and southern Portugal. Both these cycles likely show the influence of the North Atlantic Oscillation (NAO) on the occurrence and severity of droughts in Portugal. Relative to other months it was observed that cycles varied according to the common occurrence of precipitation: for the rainy months -November, December and January -cycles are similar to those for December; for the dry months -May to September -where the lack of precipitation masks the occurrence of drought, the dominant cycles are of short duration and cannot be related to the NAO or other large circulation indices to explain drought variability; for the transition months -February, March, April and October -6-year and 3-year cycles were identified, the latter being more strongly apparent in central and southern Portugal. NAO influence is again identified relative to the 6-year cycles. The short cycles are apparently associated with positive SPI, thus with wetness, not drought. Overall, results confirm the importance of the NAO as a driving force for dry and wet periods.

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Section: Discussionsupporting

confidence: 62%

Assessing drought cycles in SPI time series using a Fourier analysis

Moreira

Martins

Pereira

2015

Nat. Hazards Earth Syst. Sci.

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“…In the Mediterranean area, a correlation between the NAO, precipitation, river discharges and lake levels was also found in the Middle East and in Turkey (Cullen and deMenocal, 2000;Cullen et al, 2002;Karabörk et al, 2005;Türkes and Erlat, 2005;Kücük et al, 2009). A strong interdependence among the NAO, precipitation, river discharges and air temperature in some southern Italy regions (Brandimarte et al, 2011;Caloiero et al, 2011) was discovered.…”

Section: Introductionmentioning

confidence: 91%

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

Vita

Allocca

Manna

et al. 2012

Hydrol. Earth Syst. Sci.

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Abstract.Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation.In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO).The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period.Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis.The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30 % for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index.Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results of this study allow for the establishment of a link between a large-scale atmospheric cycle and the groundwater recharge of carbonate karst aquifers. Consequently, the winter NAO index could also be considered as a proxy to forecast the decadal variability of groundwater flow in Mediterranean karst areas.

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“…In the Mediterranean region a negative relationship between the NAO and river discharges has been found in the Middle East (Cullen and DeMenocal, 2000;Cullen et al, 2002) and in Turkey (Karabörk et al, 2005;Kalayci and Kahya, 2006), where lake levels have also been related to the NAO (Kücük et al, 2009). Within the Iberian Peninsula (hereafter IP) the influence of the NAO on river discharges has been analyzed in studies of various basins (López-Moreno et al, 2007;Trigo et al, 2004;Morán-Tejeda et al, 2011), where reasonably high correlations have been found between the NAO and streamflows, particularly in winter.…”

Section: Introductionmentioning

confidence: 99%

The response of Iberian rivers to the North Atlantic Oscillation

Lorenzo‐Lacruz

Vicente‐Serrano

López‐Moreno

et al. 2011

Hydrol. Earth Syst. Sci.

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Abstract. In this study we analyzed the influence of the North Atlantic Oscillation (NAO) on the streamflow in 187 sub-basins of the Iberian Peninsula. Monthly and one-month lagged correlations were conducted to assess the spatiotemporal extent of the NAO influence on Iberian river discharges. Analysis of the persistence of the winter NAO throughout the year was also undertaken, together with analysis of streamflow anomalies during positive and negative NAO phases. Moving-window correlation analyses were conducted to assess potential changes in the temporal evolution of the NAO influence on Iberian streamflows. The results show that the NAO has a large impact on surface water resources throughout the Iberian Peninsula during winter, and in the Atlantic watershed during autumn. We showed that water resources management and snowmelt are causing the persistent dependence of streamflows on the previous winter NAO. We found that strongly positive streamflow anomalies occurred during winter, especially in the Atlantic watershed, and provide evidence of non-stationarity and spatial variability in the NAO influence on Iberian water resources.

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North Atlantic Oscillation influences on Turkish lake levels

Cited by 51 publications

References 34 publications

Assessing drought cycles in SPI time series using a Fourier analysis

Assessing drought cycles in SPI time series using a Fourier analysis

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

The response of Iberian rivers to the North Atlantic Oscillation

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