The teleconnections between the extreme phases of the southern oscillation and precipitation patterns over Turkey

Abstract

Climatic links between monthly precipitation in Turkey and the El Niño and La Niña events using the empirical methodology of Ropelewski and Halpert are investigated. Coherent and significant precipitation responses to both the extreme phases of the southern oscillation (SO) are found in two core regions, namely western Anatolia (WA) and eastern Anatolia (EA). The geographical extent of the two regions, together with a defined signal season for each tropical event, are identified. For WA, the April-July wet period during El Niño events is the season when the teleconnection is strong and consistent. For EA, the February-June wet period during El Niño events is found to be the signal season having high rates of coherence and consistency. The occurrence of the signal season (the dry period of April-October) during La Niña events appears to be less significant in EA according to the hypergeometric model. Moreover, the annual cycle analysis implies somewhat of a modulation of regional precipitation in the WA and EA regions during the relevant signal season. From other perspectives, correlation results of seasonal precipitation and seasonal SO index values confirm the implied teleconnections, and the powers of line spectra corresponding to the El Niño occurrences supply some indications. The final aim of this work is to show some guidance for quantification of the SO-related precipitation teleconnections for the core regions by examining shifts in precipitation amounts at various percentiles as a function of the SO extremes. Overall, the results of this investigation are in good agreement with previous relevant studies (especially global-scale type) that try to understand complex global circulation dynamics. In conclusion, mid-latitude precipitation responses to the extreme phases of the SO are detectable in the climate of Turkey.

Association between three prominent climatic teleconnections and precipitation in Iran using wavelet coherence

“…long‐term periods in the SOI), the anti‐phase was detected at most of the stations. As can be seen in the results of this research, the SOI has stronger effects on precipitation in Iran, similar to the results obtained in neighbouring countries such as India, Nepal and Turkey (Mooley et al , ; Shrestha, ; Çag̀atay Karabörk and Kahya, , ). It seems that the climatic indices which are derived from sea surface temperature, such as the SOI, have more noticeable influences on the precipitation in this region compared to the climatic indices which are based on pressure systems, such as NAO, and this result is in agreement with previous studies in neighbouring regions (Çag̀atay Karabörk and Kahya, , ).…”

“…A study in Nepal showed that the influences of the SOI are very significant for Nepal's monsoon, since when the SOI is in a negative (positive) phase, rainfall is lower (higher) than the normal values (Shrestha, ). As seen in previous studies in Turkey, the SOI phases play major roles in the Turkish and the eastern Mediterranean regions' precipitation, even when the SOI is in the extreme phase (Çag̀atay Karabörk and Kahya, , ). It seems that the SOI plays a major role in the precipitation amount and occurrence in this region, and the previous studies agree with the main results of this research.…”

A multiscalar global evaluation of the impact of ENSO on droughts

“…[18] An empirical methodology similar to that adopted by Ropelewski and Halpert [1986, 1987, 1996, Piechota and Dracup [1996] and Karabörk and Kahya [2003] was used to determine the impact of El Niño and La Niña years on global drought conditions. The approach followed that of a previous study [Vicente-Serrano, 2005] that analyzed the impact of ENSO events on droughts in the Iberian Peninsula.…”

El Niño Southern Oscillation (ENSO) effects on fisheries and aquaculture

“…Where they exist, relationships between ENSO and the climate indices are generally stronger for temperature indices than for the precipitation in the region (Donat et al, 2014). However, variation in precipitation (Karabork and Kahya, 2003) and streamflow in parts of Turkey is affected by ENSO (Kahya and Karabörk, 2001) but the signal is mixed and differs between northwest and eastern Turkey. Work to date indicates that there are no obvious effects of EP El Niño in terms of surface air temperature anomalies, but CP El Niños are associated with a positive temperature anomaly in southeast Iraq and Saudi Arabia (Graf and Zanchettin, 2012).…”