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Suha Ozden Semir Over Kaan Sevki Kavak Serife Sevinc Inal 《Journal of Geodynamics》2008,46(1-2):48-62
This study defines the Late Cenozoic stress regimes acting around the Bolu Basin along the North Anatolian Fault in northwestern Turkey. The inferred regional stress regime, obtained from the inversion of measured fault-slip vectors as well as focal mechanism solutions, is significant and induces the right-lateral displacement of the North Anatolian Fault. The field observations have also revealed extensional structures in and around the Bolu Basin. These extensional structures can be interpreted as either a local effect of the regional transtensional stress regime or as the result of the interaction of the fault geometries of the dextral Duzce Fault and the southern escarpment of the North Anatolian Fault, bordering the Bolu Basin in the north and in the south, respectively.The inversion of slip vectors measured on fault planes indicates that a strike-slip stress regime with consistent NW- and NE-trending σHmax(σ1) and σHmin(σ3) axes is dominant. Stress ratio (R) values provided by inversion of slip vectors measured on both major and minor faults and field observations show significant variations of principal stress magnitudes within the strike-slip stress regime resulting in older transpression to younger transtension. These two stress states, producing dextral displacement along NAF, are coaxial with a consistent NE-trending σ3 axis. The earthquake focal mechanism inversions confirm that the transtensional stress regime has continued into recent times, having identical horizontal stress axis directions, characterized by NW and NE-trending σ1 and σ3 axes, respectively. A locally consistent NE-trending extensional, normal faulting regime is also seen in the Bolu Basin. The stress-tensor change within the strike-slip stress regime can be explained by variations in horizontal stress magnitudes that probably occurred in Quaternary times as a result of the westward extrusion of the Anatolian block. 相似文献
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R. S. Ross A. Chakraborty A. Chen L. Stefanova S. Sirdas T. N. Krishnamurti 《Meteorology and Atmospheric Physics》2007,98(3-4):137-174
Summary Climate variations in the Caribbean, largely manifest in rainfall activity, have important consequences for the large-scale
water budget, natural vegetation, and land use in the region. The wet and dry seasons will be defined, and the important roles
played by the El Ni?o-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) in modulating the rainfall during
these seasons will be discussed.
The seasonal climate forecasts in this paper are made by 13 state of the art coupled atmosphere-ocean general circulation
models (CGCMs) and by the Florida State University Synthetic Superensemble (FSUSSE), whose forecasts are obtained by a weighted
combination of the individual CGCM forecasts based on a training period. The success of the models in simulating the observed
1989–2001 climatology of the various forecast parameters will be examined and linked to the models’ success in predicting
the seasonal climate for individual years. Seasonal forecasts will be examined for precipitation, sea-surface temperature (SST), 2-meter air temperature, and
850 hPa u- and v-wind components during the period 1989–2001. Evaluation metrics include root mean square (RMS) error and Brier skill score.
It will be shown that the FSUSSE is superior to the individual CGCMs and their ensemble mean both in simulating the 1989–2001
climatology for the various parameters and in predicting the seasonal climate of the various parameters for individual years.
The seasonal climate forecasts of the FSUSSE and of the ensemble mean of the 13 state of the art CGCMs will be evaluated for
years (during the period 1989–2001) that have particular ENSO and NAO signals that are known to influence Caribbean weather,
particularly the rainfall. It will be shown that the FSUSSE provides superior forecasts of rainfall, SST, 2-meter air temperature,
and 850 hPa u- and v-wind components during dry summers that are modulated by negative SOI and/or positive NAO indices. Such summers have become
a feature of a twenty-year pattern of drought in the Caribbean region. The results presented in this paper will show that
the FSUSSE is a valuable tool for forecasting rainfall and other atmospheric and oceanic variables during such periods of
drought. 相似文献
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Sevinc Ozkul 《Climatic change》2009,97(1-2):253-283
IPCC Fourth Assessment Report (AR4) discloses that the global climate system is undoubtedly warming. Observations have shown that many natural systems, including hydrologic systems and water resources, are being affected by regional climate changes, particularly temperature increases. Eventually, these effects will have to be considered in water resources planning and management. Accordingly, need is indicated to evaluate the impact of expected climate change on hydrology and water resources at regional and local levels. The presented paper summarizes the results of the sub-project studies under the United Nations Development Program-Global Environment Facility (UNDP-GEF) Project. The studies cover the generation of climate change scenarios, modeling of basin hydrology, and testing the sensitivity of runoff to changes in precipitation and temperature. Simulation results of the water budget model have shown that nearly 20% of the surface waters in the studied basins will be reduced by the year of 2030. By the years 2050 and 2100, this percentage will increase up to 35% and more than 50%, respectively. The decreasing surface water potential of the basins will cause serious water stress problems among water users, mainly being agricultural, domestic and industrial water users. 相似文献
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