İklim ve Deniz Bilimleri

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http://hdl.handle.net/11527/25368

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  • Öge
    Impact of atmospheric rivers on the winter snowpack in the headwaters of Euphrates-Tigris basin
    (Springer, 2024) Ezber, Yasemin ; Bozkurt , D. ; Şen, Ömer Lütfi ; 0000-0002-4512-685X ; 0000-0002-8186-8594 ; İklim ve Deniz Bilimleri
    Understanding the hydrometeorological impacts of atmospheric rivers (ARs) on mountain snowpack is crucial for water resources management in the snow-fed river basins such as the Euphrates-Tigris (ET). In this study, we investigate the contribution of wintertime (December-January–February) ARs to precipitation and snowpack in the headwater regions of the ET Basin for the period of 1979–2019 using a state-of-the-art AR catalog and ERA5 reanalysis data. The results show that AR days in the headwaters region could be warmer by up to 3 °C and wetter by over 5 mm day−1 compared to non-AR days. The contribution of ARs to the total winter precipitation varies from year to year, with a maximum contribution of over 80% in 2010 and an average contribution of 60% over the 40-year period. While snow accumulation on AR days shows spatial variability, the average snow contribution is 27% of the seasonal average, ranging from 12 to 57% for different years. The south-facing parts of the mountain range experience significant snowmelt, with contributions ranging from 15 to 80% for different years. The high total precipitation (60%) and low snowpack (27%) contribution can be attributed to the semi-arid characteristics of the region and the occurrence of rain-on-snow events, where rain falling on existing snow rapidly melts the snowpack. The findings have implications for water resource management and call for continued research to improve our knowledge of ARs and their interactions with the complex terrain of the ET Basin.
  • Öge
    Latitude or altitude as the future refugium? A case for the future of forests in Asia Minor and its surroundings
    (Wiley, 2024) Ekberzade, Bikem ; Yetemen, Ömer ; Ezber, Yasemin ; Şen, Ömer Lütfi ; Dalfes, Hasan Nüzhet ; orcid.org/0000-0002-3271-2040 ; orcid.org/0000-0003-1593-3519 ; orcid.org/0000-0002-4512-685X ; orcid.org/0000-0002-8186-8594 ; orcid.org/0000-0002-2522-8381 ; İklim ve Deniz Bilimleri
    At the current juncture with climate change, centennial projections of species distributions in biodiversity hotspots, using dynamic vegetation models may provide vital insight into conservation efforts. This study aims to answer: (1) if climate change progresses under a business-as-usual scenario of anthropogenic emissions for this century, how may the forest ranges be affected? (2) will there be potential regional extinctions of the taxa simulated? (3) may any site emerge as a potential refugium? Study Area: Anatolian Peninsula and its surroundings, longitudes 24–50° E, latitudes 33–46° N. Time Period: 1961-2100. Major Taxa Studied: 25 woody species and a C3 grass-type. Method: Keeping a spatial window large enough to track potential changes in the vegetation range and composition especially in the mountain ranges within the study area, we parameterized a process-based regional-to-global dynamic vegetation model (LPJ-GUESS v 4.1), forced it with ERA5-Land reanalysis for the historical period, and five different bias-corrected centennial global circulation model (GCM) datasets under SSP5-8.5, and simulated the dynamic responses of key forest species. Bivariate spatio-temporal maps from the simulation results were constructed for final analysis. Results: A significant increase in woody taxa biomass for the majority of our study area, towards the end of the century was simulated, where temperate taxa with high tolerance for drought and a wider range of temperatures took dominance. The mountain ranges in our study area stood out as critical potential refugia for cold favoring species. There were no regional extinctions of taxa, however, important changes in areal dominance and potential future forest composition were simulated. Main Conclusions: Our simulation results suggest a high potential for future forest cover in our study region by the end of the century under a high emissions scenario, sans human presence, with important changes in vegetation composition, including encroachment of grasslands ecosystems by woody taxa.