Türkiye’s 80-Year Climate Record Reveals Warming, Stilling Winds and Atlantic Fingerprint

A sweeping analysis of eight decades of daily weather observations from across Türkiye has produced one of the most detailed statistical portraits yet of how the country’s climate has shifted since the mid-1940s, and of which large-scale atmospheric drivers actually matter for its year-to-year variability. The study, published in Theoretical and Applied Climatology, draws on records from 135 weather stations that contribute to the Global Surface Summary of the Day (GSOD) archive, spanning the period from 1946 to 2025. Its central findings are stark in their simplicity: Türkiye is warming, its near-surface winds are slowing, and the powerful modes of Northern Hemisphere circulation known as the North Atlantic Oscillation and the Arctic Oscillation leave a measurable imprint on the country’s pressure and rainfall patterns, while the stratospheric Quasi-Biennial Oscillation, often invoked in climate teleconnection studies, appears to have essentially no influence on the surface climate variables examined.

The research team, led by Kutubuddin Ansari and Emine Tanır Kayıkçı of the Department of Geomatics Engineering at Karadeniz Technical University in Trabzon, approached the problem with a deliberately standardized methodology. Rather than comparing raw temperatures or rainfall totals, which vary enormously between a coastal station on the Aegean and a high plateau site in eastern Anatolia, the authors converted every measurement into a standardized anomaly using Z-transformation. This statistical technique expresses each daily or annual value as a departure from the long-term mean, scaled by the standard deviation of the record at that station. The result is a dimensionless quantity that allows a fair comparison of climate behavior across radically different geographic settings, from the humid Black Sea coast to the semi-arid interior of Central Anatolia.

With the anomalies in hand, the researchers computed long-term trends for four surface variables: temperature, sea-level pressure, wind speed and precipitation. The signal that emerges most clearly from the data is a nationwide warming tendency, one that is particularly pronounced in central and western Türkiye. This spatial pattern is consistent with the country’s position at the intersection of several vulnerable climate zones. Türkiye sits at the eastern edge of the Mediterranean basin, a region that climate model projections have long identified as a hotspot where warming is expected to outpace the global average, and it simultaneously experiences continental influences from the Anatolian interior and maritime influences from the Black Sea, the Aegean and the Mediterranean. The new observational analysis confirms that the warming signal is not confined to one corner of the country but is a genuinely national phenomenon, with its strongest expression in the interior and western provinces.

The second robust signal in the record is a decline in wind speed, a finding that echoes what atmospheric scientists have called global terrestrial stilling. Studies published over the past fifteen years have documented widespread decreases in near-surface wind speeds across many continents, with proposed explanations ranging from increases in surface roughness driven by vegetation growth and land-use change to shifts in large-scale atmospheric circulation. The Turkish data add another national record to that growing body of evidence. For a country that has invested heavily in wind power capacity along its Aegean and Marmara coasts, the long-term behavior of surface winds is not an academic curiosity; it bears directly on the reliability of one of the fastest-growing segments of the national energy system. The study’s finding of an overall decline in wind speed across the 1946 to 2025 period will therefore be scrutinized closely by both climatologists and energy planners.

Not every variable in the analysis tells such a decisive story. Sea-level pressure and precipitation both exhibit trends that are weaker and far more regionally variable than those for temperature and wind. This is in many ways exactly what one would expect. Precipitation over Türkiye is governed by a complicated interplay of Mediterranean storm tracks, Black Sea moisture fluxes, orographic lifting over the North Anatolian mountains and the Taurus range, and the seasonal migration of the subtropical high. Averaging such a heterogeneous set of processes into a single national trend risks obscuring the local signals, and the study’s authors appear to have taken that heterogeneity seriously by reporting the regional variability rather than forcing a single narrative onto the rainfall data.

One of the study’s most technically interesting results concerns the relationships among the surface variables themselves. When the researchers computed correlations between temperature, pressure, wind and precipitation anomalies, they found that the variables are generally only weakly correlated with one another. This weak internal coupling is a meaningful diagnostic. It indicates that each variable responds to a different combination of regional atmospheric circulation patterns and local geographical controls, such as elevation, distance from the sea and topographic exposure. In a strongly coupled system, a change in circulation would move temperature, pressure, wind and rainfall together in predictable ways; in the Turkish record, each variable appears to march to its own drummer to a considerable degree, which complicates any attempt to reconstruct one variable from another or to attribute all observed changes to a single driver.

The heart of the paper, however, lies in its search for teleconnections, the statistical fingerprints that distant oscillations leave on regional climate. The authors examined three candidates. The first, the Quasi-Biennial Oscillation, is a stratospheric phenomenon in which equatorial winds alternate between easterly and westerly phases on a cycle of roughly 28 months, descending through the stratosphere from about 10 hPa down to about 70 hPa and beyond. The QBO is known to modulate the polar vortex, the Madden-Julian Oscillation and, in some studies, monsoon systems, so a link to mid-latitude surface climate is physically plausible. Yet when Ansari and Kayıkçı tested the QBO at both the 10 hPa and 70 hPa levels against their Turkish surface records, they found no statistically significant relationship with any of the four climate variables. For Türkiye, at least, the stratospheric biennial pulse appears to be a non-player at the surface.

The story changes when the analysis turns to the North Atlantic Oscillation and the Arctic Oscillation. The NAO describes a seesaw in atmospheric mass between the Azores high and the Icelandic low, while the AO captures the annular mode of the Northern Hemisphere, a ring of alternating pressure between the Arctic and the mid-latitudes. Both are dominant modes of extratropical variability, and both steer storm tracks and air masses across Europe and the eastern Mediterranean. The annual correlation analysis revealed a significant positive relationship between the NAO and precipitation, and between the AO and sea-level pressure, over Türkiye. In other words, when the NAO is in a positive phase, Turkish precipitation tends to be higher in the annual mean, and the AO leaves a clear positive signature in the country’s surface pressure record. These are exactly the kinds of relationships one would anticipate from the physics of mid-latitude circulation, in which positive NAO phases strengthen westerly flow and shift storm activity in ways that alter moisture delivery to Anatolia.

To quantify how much of the Turkish climate variability these circulation modes can actually explain, the researchers built combined regression models using the NAO and AO indices together as predictors. For sea-level pressure, the combined NAO-AO model explained 8.0 percent of the variance, a result the authors report as statistically significant. Eight percent may sound modest, and in absolute terms it is, but for annual mean surface pressure over a region as topographically and climatologically complex as Türkiye, a statistically robust eight percent is a genuine signal. It confirms that the mid-latitude annular modes are relevant players in Turkish climate variability, even if they are far from the whole story. By contrast, the corresponding regression models for temperature, wind speed and precipitation were weak or only marginally significant, underscoring that local and regional factors, along with the broader warming trend, dominate those variables more than any single teleconnection index can.

The broader significance of the study lies in its careful separation of what matters and what does not for Turkish climate variability. Over an 80-year window, the dominant signals are a clear warming trend concentrated in the central and western regions, a widespread stilling of near-surface winds, and a statistically detectable but partial influence of the NAO and AO on pressure and rainfall. The QBO, despite its importance in stratospheric dynamics and its documented teleconnections elsewhere in the world, drops out entirely at the surface over Türkiye. For climate modelers working on the eastern Mediterranean, these results provide a benchmark for evaluating which modes of variability regional simulations must capture, and for water managers, energy planners and agricultural stakeholders in Türkiye, the message is that the country’s climate future will be shaped less by exotic stratospheric oscillations than by the relentless background warming and the shifting behavior of the Atlantic-centered circulation patterns on its doorstep.

Subject of Research: Long-term climate variability and teleconnection patterns over Türkiye

Article Title: Long-term climate anomalies in Türkiye and their relationships with the QBO, NAO and AO

Article References: Ansari, K., & Kayıkçı, E. T. (2026). Long-term climate anomalies in Türkiye and their relationships with the QBO, NAO and AO. Theoretical and Applied Climatology, 157(10), Article 613. https://doi.org/10.1007/s00704-026-06541-z

Image Credits: AI Generated

DOI: 10.1007/s00704-026-06541-z

Keywords: Türkiye, climate change, temperature trends, wind speed, precipitation, North Atlantic Oscillation, Arctic Oscillation, Quasi-Biennial Oscillation, teleconnections, sea-level pressure, GSOD stations, Theoretical and Applied Climatology