H. Nüzhet Dalfes

A comparative assessment of different methods for detecting inhomogeneities in Turkish temperature data set

A combination of different methods is described whereby climatological time series can be tested for inhomogeneities using relative homogeneity techniques. The method set includes graphical analysis, a non-parametric Kruskal–Wallis homogeneity test and a Wald–Wolfowitz runs test application to the annual mean difference temperature series between highly correlated stations. A series of Monte Carlo simulation studies was carried out, which determined the inhomogeneity detection efficiencies of these tests. The procedure is statistically rigorous and provides estimates of the time and magnitude of change in the mean. Its application to annual mean temperature differences series for 82 Turkish climate stations indicates that the method set is a valuable tool for testing time series.

March 1987 Cyclone (Blizzard) over the Eastern Mediterranean and Balkan Region Associated with Blocking

Abstract The March 1987 blizzard over the eastern Mediterranean and Balkan regions is investigated. Northern Hemispheric and regional 250- and 850-hPa geopotential heights illustrate the formation of blocking over northern Europe and cyclogenesis over the considered area. The 850-hPa analyses and National Centers for Environmental Prediction Eta model simulations are in good agreement. Temporal analyses of temperature and precipitation fields show that a cold air surge over the region resulted in a decrease in the daily temperatures of up to 15°C and a heavy accumulation of snow in the early days of the storm. Spatial analyses of the precipitation field reveal that the most snowfall-affected regions were northwestern Turkey and the Balkan countries.

Environmental Vulnerability of Early Societies: Some Reflections on Modeling Issues

Understanding the vulnerability of early societies to climatic fluctuations and local environmental degradation requires development of a hierarchy of system dynamical models. It is through the development and verification process of such models that we will arrive at explanations of abrupt demographic and/or cultural changes documented by archaeology. Any modeling process will have to ask questions and make decisions about the definition of the system of interest, the appropriate spatial and demographic aggregation level to be adopted and details of the physical, ecological and cultural processes to be included.

A new parallel programming language fortress: Features and applications

An overview of a newly designed parallel programming language is presented in this paper. Fortress, an outcome of the high productivity computing systems program at DARPA, is examined through its features like mathematical notation, implicitly parallel nature and ease of library coding, its potential to grow easily and its interchangeable program parts. Code writing is discussed through examples. The tests for its scalability are done with several array types and also a comparison of an application written both in C and Fortress is presented. The usability and the future of the language in HPC environments are also discussed.