İstanbul Şehir Isı Adası Etkisinin Farklı Arazi Kullanım Verileri İle Wrf Modeli Kullanılarak Analizi

Abstract

Dünya nüfusu 17. Yüzyıla kadar oldukça yavaş bir trendle artış göstermiştir. Ancak Sanayii devrimi ve teknolojik gelişmeler sayesinde nüfus, son 350 yılda 500 milyondan 7 milyara yükselmiştir. ABD Milli Bilimler Akademisi’nce bu sayının 2075 yılına kadar 30 milyara ulaşması öngörülmektedir. Bu durumun sebep olduğu pek çok problemin başında kalabalık şehirler gelmektedir. Sanayii devrimi yıllarında dünya nüfusunun yalnızca %10’u şehirlerde yaşarken günümüzde bu oranın yaklaşık %50 olduğu Birleşmiş Milletler raporunda belirtilmiştir. İklim üzerinde gözlenen küresel değişimler sonucunda meteorolojik hadiselerin ekstrem boyutlarda gerçekleşmesi günümüzün en önemli problemlerinden biridir. Küresel iklim değişimine ek olarak, şehirleşmenin doğurduğu bir sonuç olan şehirlerin mikro iklim yapılarında da değişimler gözlenmektedir. Örneğin şehirleşmenin yoğun olduğu alanlarda çevreye göre daha sıcak bölgeler oluşmaktadır. Avrupa’da 2003 yılında yaşanan ve yaklaşık 70000 kişinin ölümüne sebep olan sıcak hava dalgası hadisesi bu soruna örnek olarak verilebilir. Bu bilgiler ışığında şehirleşmenin, küresel iklim değişimine temel hazırlayan faktörlerden biri olduğu söylenebilir. Artan nüfus ve değişen koşullar İstanbul’un arazi kullanımı profilini de değiştirmektedir. Geçmişten günümüze bakıldığında İstanbul için değişim, genel olarak yeşil alanların azalması ve şehirleşmenin artışı şeklinde gözlenmiştir. Hali hazırda yapımı süren 3. Köprü düşünüldüğünde İstanbul’un ayakta kalan son yeşil alanları olan Kuzey Ormanları’nın şehirleşme olasılığı üzerine bu çalışmada, bu durumun şehir ikliminde yaratacağı olası değişikliklerin araştırılması ve tahmini hedeflenmiştir. Belirlenen sıcak dalga günlerinde İstanbul’un çeşitli ölçüm istasyonundan alınmış sıcaklık verilerinin analizi ve arazi kullanım analizleri ile İstanbul üzerindeki şehir ısı adaları incelenecek ve The Weather Research and Forecasting (WRF) Model kullanılarak, farklı arazi kullanımı dosyaları (USGS, CORINE) ile sıcak dalga günlerinde verdiği tahmin sonuçları gözlem verileri ile karşılaştırılacaktır. Ayrıca, Avrupa Çevre Ajansı (European Environment Agency) tarafından hazırlanan CORINE (Coordinated Information on the Environment) arazi kullanımı verisi üzerinde yapılacak modifikasyonlarla, İstanbul için hazırlanan senaryolar WRF modeli ile uygulanarak tahmin yapılacaktır. Böylelikle daha güncel bir arazi kullanım verisiyle WRF modelinin tahmin yeteneğinin test edilmesi ve şehir ısı adası etkisinin irdelenmesi hedeflenmiştir.

The world's population growth has been relatively slow until 17. century. Because of the industrial revolution and technological advances, population increased to 7 billion 500 million in the last 350 years. By the year 2075, US National Science Academy states that this number is projected to reach 30 billion. This situation causese the crowded cities. While Industrial revolution, people living in the city ratio was only 10% of the world population. Today, this ratio is about 50% is stated in the report of the United Nations. Extreme meteorological events occur as a result of the global changes in the climate is one of the most important problems. In addition to global climate change in the microclimate of buildings in the city, which is a consequence of urbanization, changes are observed. For example, according to the environment in areas where dense urban areas consist warmer regions. It experienced in 2003, the heat wave in Europe that killed approximately 70,000 people given incident as an example of this problem. Urbanization in the light of this information, said to be one of the main factors of global climate change prepared. City areas affected by weather and climate as well as having an effect on a local scale weather and climate. City climate is expressed as local climate, by the interaction between the built-up areas and the changing climate of the region. The climate of the city is a mesoclimate which as a spatial size of about 250 km. Cities and other built-up areas around climate changes partly vary with made by the people during the urbanization on surface. Surface in the city due to the displacement of native vegetation with buildings and streets are often rough and dry. Buildings along the street, three-dimensional surface of a city create "street canyons" form. This situation changes the solar radiation, the surface temperature, evaporation, heat storage, which may affect the turbulence and wind structure of the city and change substantially near surface atmospheric conditions. All of them, as well as human activities in the city, the atmosphere in the heat source, it will directly affect the temperature of the greenhouse gases and pollutants, image and influence of atmospheric conditions on city also produce noise pollution. A slightly larger scale, in urbanization and precipitation may lead to changes in the wind profile. To sum up, there are four main elements that make the city climate. These; natural vegetation and land areas, displaced by the place with three-dimensional urban structure, reduction of green areas, the reduction by the surface of the long-wave emission urban canyons and greenhouse gases, atmospheric pollutants and can be listed as the release of waste heat. It first needs to understand better the concept of urban heat island for an understanding of climate change caused by urbanization in local scale. For city climate, temperature comes to mind when it comes to climate elements. The changes generated in the city by human action, according to the rural areas, in an urban environment that leads to higher temperatures. Based on this information, urban heat island is defined as the temperature difference between the urban environment and rural areas. This definition is used for the first time in London in 1820 by Luke Howard. In dense urban areas, cities on the basis of average annual temperature is 1-2 ° C warmer compared with rural areas. This difference can be observed in urban centers further increase up to 6-12 ° C. Thermal air circulation that occurs due to the intense heat creates a layer of fog over the city together with air pollution. This layer leads to the prevention of overheating and causing the inversion air circulation over the city during the night. This situation creates an atmosphere harmful to the health of the city combined with air and pollutants cannot move in the horizontal direction. Also the Heat waves are very important for urban climate. Heat waves, observed over a long time period described as unusually hot weather. heat waves, an important consequence of climate change, is associated with atmospheric circulation conditions. Heat waves generally are associated with stationary half 500 hPa thickness represented by positive anomalies special atmospheric circulation pattern. this pattern formation mechanism explaining the dynamic crash in the area of heat waves, clear sky, calm winds, warm air advection and the surface can be expressed in the form of prolonged hot weather. Istanbul, is located between 41.01 ° N and 28.58 ° E latitude and longitude, in the north west of Turkey. It is the most crowded city in Turkey and Europe with approximately 15 million inhabitants. Istanbul has a surface area of 5343 km2 and consists of 39 districts. City is considered as a financial and industrial center of Turkey. Istanbul Bosphorus divides the city and the city is situated on the east-west direction in the Asian and European continents. Approximately 30 km long Bosphorus line in the task sees the border between the two continents. Black Sea is located in the north of the city and Sea of Marmara is located in the south of the city. Urbanization heavily on the shores of the Marmara Sea, is located in the southern part of the city. However, because of the North Marmara Fault Line is very close to this region after the 1999 earthquake began the expansion of the city towards the north. The northern part of the city extends towards the Black Sea is mostly surrounded by large forests. WRF model and two different land use data are used for this study. The Weather Research and Forecasting (WRF) Model is a next-generation mesoscale numerical weather prediction system designed for both atmospheric research and operational forecasting needs. It features two dynamical cores, a data assimilation system, and a software architecture facilitating parallel computation and system extensibility. The model serves a wide range of meteorological applications across scales from tens of meters to thousands of kilometers. The effort to develop WRF began in the latter part of the 1990's and was a collaborative partnership principally among the National Center for Atmospheric Research (NCAR), the National Oceanic and Atmospheric Administration (represented by the National Centers for Environmental Prediction (NCEP) and the (then) Forecast Systems Laboratory (FSL)), the Air Force Weather Agency (AFWA), the Naval Research Laboratory, the University of Oklahoma, and the Federal Aviation Administration (FAA). WRF can generate atmospheric simulations using real data (observations, analyses) or idealized conditions. WRF offers operational forecasting a flexible and computationally-efficient platform, while providing recent advances in physics, numerics, and data assimilation contributed by developers across the very broad research community. WRF is currently in operational use at NCEP, AFWA, and other centers. A growing population creates changing conditions on land use profile of Istanbul. When viewed from past to present changes to Istanbul, it was generally observed in the form of reduced of green areas and growth of the urbanization. The construction of the third bridge, considering that Istanbul's last green spaces left standing in this study on the possibility of North Forests urbanization, the study of possible changes in climate will be created in this case the city was targeted and estimated. Determination of heat wave days in the received temperature data from various measuring stations in Istanbul analysis and land use analysis and urban heat island on Istanbul will be examined and The Weather Research and Forecasting (WRF) model using different land-use files (USGS, CORINE) with the heat wave days given that the estimated results will be compared with observation data. Additionally, the European Environment Agency (European Environment Agency) prepared by CORINE (Coordinated Information on the Environment) with modifications to the land use data, scenarios prepared for Istanbul will be made estimated by applying the WRF model.