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Yayın Impact of climate change and land cover dynamics on nitrate transport to surface waters(Springer Science and Business Media Deutschland GmbH, 2024-03) Boyacıoğlu, Hülya; Günaçtı, Mert Can; Barbaros, Filiz; Gül, Ali; Gül, Gülay Onuşluel; Öztürk, Tuğba; Kurnaz, M. LeventThe study investigated the impact of climate and land cover change on water quality. The novel contribution of the study was to investigate the individual and combined impacts of climate and land cover change on water quality with high spatial and temporal resolution in a basin in Turkey. The global circulation model MPI-ESM-MR was dynamically downscaled to 10-km resolution under the RCP8.5 emission scenario. The Soil and Water Assessment Tool (SWAT) was used to model stream flow and nitrate loads. The land cover model outputs that were produced by the Land Change Modeler (LCM) were used for these simulation studies. Results revealed that decreasing precipitation intensity driven by climate change could significantly reduce nitrate transport to surface waters. In the 2075–2100 period, nitrate-nitrogen (NO3-N) loads transported to surface water decreased by more than 75%. Furthermore, the transition predominantly from forestry to pastoral farming systems increased loads by about 6%. The study results indicated that fine-resolution land use and climate data lead to better model performance. Environmental managers can also benefit greatly from the LCM-based forecast of land use changes and the SWAT model’s attribution of changes in water quality to land use changes. Graphical abstract: (Figure presented.).Yayın Projected future changes in extreme climate indices over Central Asia using RegCM4.3.5(MDPI, 2023-06) Öztürk, TuğbaThis work projected future extreme climate indices' changes over Central Asia (The Coordinated Regional Climate Downscaling Experiment-CORDEX Region 8). Changes were calculated for 2071-2100 relative to 1971-2000. Climate simulations were obtained by downscaling the RegCM4.3.5 to 50 km resolution under RCP4.5 and 8.5 with HadGEM2-ES and MPI-ESM-MR. The results indicate that the Central Asian domain will experience warmer and more extreme temperatures with increasing radiative forcing. The annual lowest value of minimum daily temperature was simulated to increase remarkably, up to 8 degrees, especially in high latitudes, with a more than 12 degree increase projected over Siberia. A strong growth in the percentage of warm nights and an increase in the days of warm spells for the whole region, with a decrease in cold spell duration, are anticipated. Model results show an expected reduction of up to 30% in precipitation totals over the domain, except for the increased precipitation over Siberia, the Himalayas, and Tibetan Plateau. Extreme precipitation events are projected to have an increase of 20% over the whole domain, with an 80% increase over high topographical areas.Yayın The emergence of projected scaled patterns of extreme temperatures over Europe(Frontiers Media SA, 2023-06-28) Öztürk, Tuğba; Canbaz, Emine; Bilgin, Başak; Matte, Dominic; Kurnaz, Mehmet Levent; Christensen, Jens HesselbjergThis work investigates the scalability of extreme temperatures over the European domain with global warming levels. We have used the EURO-CORDEX ensemble of regional model simulations at 0.11° resolution for daily minimum and maximum temperatures to analyze future changes in extreme weather daily events. Scaling with the annual mean global warming modeled by the driving GCM was applied to future extreme temperature indices changes. Regional changes in each index were scaled by corresponding global warming levels obtained from GCMs. This approach asserts that regional patterns of climate change and average global temperature change are linearly related. It can provide information regarding climate change for periods or emission scenarios when no simulations exist. According to the results, the annual minimum of the lowest temperature of the day (TNn) increases more than the annual maximum of the highest temperature of the day (TXx) for Europe. The multi-model mean of the changes in scaled patterns of extreme temperatures emerges early, around 2020, even before it becomes robust. Individual scaled patterns of TNn and TXx emerge from around 2040.Yayın The Worldwide C3S CORDEX Grand Ensemble A Major Contribution to Assess Regional Climate Change in the IPCC AR6 Atlas(American Meteorological Society, 2022-12) Diez-Sierra, Javier; Iturbide, Maialen; Gutierrez, Jose M.; Fernandez, Jesus; Milovac, Josipa; Cofino, Antonio S.; Cimadevilla, Ezequiel; Nikulin, Grigory; Levavasseur, Guillaume; Kjellstrom, Erik; Bulow, Katharina; Horanyi, Andras; Brookshaw, Anca; Garcia-Diez, Markel; Perez, Antonio; Bano-Medina, Jorge; Ahrens, Bodo; Alias, Antoinette; Ashfaq, Moetasim; Bukovsky, Melissa; Buonomo, Erasmo; Caluwaerts, Steven; Chou, Sin Chan; Christensen, Ole B.; Ciarlo, James M.; Coppola, Erika; Corre, Lola; Demory, Marie-Estelle; Djurdjevic, Vladimir; Evans, Jason P.; Fealy, Rowan; Feldmann, Hendrik; Jacob, Daniela; Jayanarayanan, Sanjay; Katzfey, Jack; Keuler, Klaus; Kittel, Christoph; Kurnaz, Mehmet Levent; Laprise, Rene; Lionello, Piero; McGinnis, Seth; Mercogliano, Paola; Nabat, Pierre; Öztürk, Tuğba; Panitz, Hans-Jurgen; Paquin, Dominique; Pieczka, Ildiko; Raffaele, Francesca; Remedio, Armelle Reca; Scinocca, John; Sevault, Florence; Somot, Samuel; Steger, Christian; Tangang, Fredolin; Teichmann, Claas; Termonia, Piet; Thatcher, Marcus; Torma, Csaba; van Meijgaard, Erik; Vautard, Robert; Warrach-Sagi, Kirsten; Winger, Katja; Zittis, George; Önol, BarışThe collaboration between the Coordinated Regional Climate Downscaling Experiment (CORDEX) and the Earth System Grid Federation (ESGF) provides open access to an unprecedented ensemble of regional climate model (RCM) simulations, across the 14 CORDEX continental-scale domains, with global coverage. These simulations have been used as a new line of evidence to assess regional climate projections in the latest contribution of the Working Group I (WGI) to the IPCC Sixth Assessment Report (AR6), particularly in the regional chapters and the Atlas. Here, we present the work done in the framework of the Copernicus Climate Change Service (C3S) to assemble a consistent worldwide CORDEX grand ensemble, aligned with the deadlines and activities of IPCC AR6. This work addressed the uneven and heterogeneous availability of CORDEX ESGF data by supporting publication in CORDEX domains with few archived simulations and performing quality control. It also addressed the lack of comprehensive documentation by compiling information from all contributing regional models, allowing for an informed use of data. In addition to presenting the worldwide CORDEX dataset, we assess here its consistency for precipitation and temperature by comparing climate change signals in regions with overlapping CORDEX domains, obtaining overall coincident regional climate change signals. The C3S CORDEX dataset has been used for the assessment of regional climate change in the IPCC AR6 (and for the interactive Atlas) and is available through the Copernicus Climate Data Store (CDS).Yayın Projections of future change of climatology and extreme weather events in the Mediterranean Basin, by the HIRHAM5 regional climate model(Marmara Üniversitesi, 2022-03-30) Öztürk, TuğbaIn this study, changes in temperature and precipitation climatology and extreme weather events over the Mediterranean Basin including Turkey were investigated using HIRHAM5 driven by global climate models such as EC-EARTH, HadGEM2-ES, and NorESM1-M for 2011-2100 compared to 1971-2000. RCP4.5 and RCP8.5 scenario outputs of global climate models were used as forcing data. Daily mean temperature and precipitation variables are used to compute extreme indices. Extreme indices were calculated for the period of 2071-2100 compared to the reference period. According to the results, the severity of temperature- and precipitation-based indices will be expected to increase throughout the century with increasing radiative forcing. Minimum of minimum temperatures will increase more pronounced over the northern Mediterranean, which is referred to as climate change hot spots, whereas the increase in a maximum of maximum temperatures is moderate over land areas. A decrease in total wet-day precipitation is expected while the number of dry days is expected to increase. Therefore, the Mediterranean Basin and Turkey will have warmer and drier conditions compared to present climate conditions.Yayın Avrupa'daki aşırı hava olaylarının öngörülen değişikliğinin ölçeklenebilirliği(Jeoloji Mühendisleri Odası Yayınları, 2024-04-19) Öztürk, Tuğba; Canbaz, Emine; Kurnaz, Mehmet Levent; Çan, Tolga; Tekin, Senem; Pınarcı, Emre; Kadakçı Koca, Tümay; Koçkar, Mustafa Kerem; Olgun, Şeyda; Güler, Cüneyt; Sarı, Erol; Tiringa, DenizBu çalışma, küresel ısınma seviyeleri ile Avrupa üzerinde aşırı hava olaylarının ölçeklenebilirliğini araştırmaktadır. Bu amaçla, EUROCORDEX 0,11° çözünürlüklü bölgesel iklim modeli projeksiyonlarının günlük minimum ve maksimum sıcaklık ve günlük yağış değişkenleri 1°C, 2 °C ve 3°C küresel ısınmaya yönelik aşırı hava olaylarının gelecekteki değişikliklerini analiz etmek için kullanılmıştır. Çeşitli ekstrem iklim indislerindeki değişime, her bir bölgesel iklim modelini koşmak için kullanılan küresel iklim modelinden elde edilen yıllık ortalama küresel sıcaklık değişimi ile basit bir ölçeklendirme yöntemi uygulanmıştır. Yüzyılın sonunda yıllık minimum günün en düşük sıcaklığı (TNn), yıllık maksimum günün en yüksek sıcaklığı (TXx) ile karşılaştırıldığında daha fazla artmaktadır. Yıllık maksimum günün en yüksek sıcaklığı (TXx) ve yıllık maksimum günün en düşük sıcaklığı (TNx) indislerinin ölçeklenmiş sinyallerindeki değişiklik, her iki aşırı iklim indisi de yaz mevsiminde meydana geldiğinden dolayı, Akdeniz Havzası ve Orta Avrupa’da daha yüksek ve Kuzey Avrupa’da daha az olmak üzere benzer alansal değişiklikler göstermektedir. Aynı şekilde, yıllık maksimum günün en düşük sıcaklığı (TXn) ve TNn kış mevsiminde meydana geldiği için her ikisi de kuzey kesimde daha yüksek bir artışla benzer bir alansal örüntü göstermektedir. Ayrıca bu çalışmada belirli ekstrem iklim indisleri ile ilgili olarak minimum ve maksimum sıcaklıklar ile nemli ve kurak kalıcı koşulların ölçekli örüntülerinin ortaya çıkışı da tespit edilmiştir. TNn indisinin ölçekli örüntülerinin ortaya çıkışı 2040 civarında gerçekleşirken, TXx indisinin ölçekli örüntülerinin ortaya çıkışı 2050 civarındadır. Bireysel GCM-RCM çiftleri, her iki indeks için de belirtilen zamanlardan başlayarak sabit alansal örüntülere sahip olma eğilimindedir. Tüm modellerden elde edilen ortalama örüntüler ise, bireysel modellerdendaha erken ortaya çıkmaktadır. 1 mm ve üstündeki yağışlı günlerde yıllık toplam yağış değerlerini içeren PRCPTOT indisinde ise tüm modellerin ortalamasını içeren sonuçlara göre yüzyılın sonunda Avrupa’nın kuzeyinde yoğun artış gözlenirken, Kuzey Afrika ülkeleri boyunca daha şiddetli olmak üzere Akdeniz’e kıyısı olan ülkelerde yağışlarda azalma öngörülmektedir.Yayın The emergence of projected scaled patterns of extreme weather events over Europe(European Geosciences Union (EGU), 2023-04-28) Öztürk, Tuğba; Canbaz, Emine; Bilgin, Başak; Matte, Dominic; Kurnaz, Mehmet Levent; Christensen, Jens HesselbjergThis work investigates the scalability of wet and dry persisting condition patterns over the European domain with global warming levels. For this aim, we have used the EURO-CORDEX ensemble of regional climate projections at 0.11° grid-mesh for daily minimum and maximum temperature and precipitation to analyze future changes in extreme weather events addressing climate warming levels of 1°C, 2°C, and 3°C, respectively. A simple scaling with the annual mean global mean temperature change modeled by the driving GCM is applied. The annual minimum of daily minimum temperature (TNN) is found to increase more compared to the annual maximum of daily maximum temperature (TXX) at the end of the century. We also identify the emergence of the scaled patterns of minimum and maximum temperatures and wet and dry persisting conditions about certain extreme weather indices. The emergence of the scaled patterns of TNN occurs from around 2040, whereas TXX pattern is emerging around 2050. Individual GCM-RCM pairs tend to have stable spatial patterns since then for both indices. The ensemble mean patterns are emerging earlier than the individual models.
