GEOGRAPHICAL RESEARCH
Year:2008 | Volume:22 | Issue:4 (87)|Papers Count:8

Regression methods are most applied technique in trend analysis. The most recent research paid more attention to parametric methods; however, there are many techniques to analyze regression. In this paper, three methods of linear regression have introduced and applied to Tabriz temperature based on assumpation of its linearity in behavior. So parametric, non-parametric and Byas regression have fitted to annual temperature of Tabriz. The best regression model have chosen based on t-statistic, precision, deterministic, obviously and residual tests. Based on non-parametric method annual temperature trend of Tabriz has on interval of 0.03- 0.04 degree centigrade per year.

The present study the examines the spatial-temporal behavior of Siberian high using mean daily sea level pressure (SLP) in the Northern Hemisphere (20-80 lat and 40-140 Ion) from NCEP/NCAR reanalysis data for the period 1950-2005. The Original data were analyzed by means of Matlab and Surfer. The studies showed that Siberian high is the most important atmospheric center of action in Eurasia during the cool months. The Siberian high as a seasonal synoptic system for 8 October to 1 April dominated over Eurasia. Appearance of 1024 hpa isobar has been selected as the indicator of Siberian high occurrence. Spatial configuration of Siberian high in one hand depends on situation, extend and intensity of sub polar low pressure and on the other hands depends on Tabbat and Pamir Plateau. Therefore the shape of Siberian high is similar to an irregular triangle. Finally we recognize that the role of Siberian high in climate of Iran not only depends on intensity of this system but also depends on intensity of sub polar low pressure and leading tongue of Siberian high to Iran.

Nowadays, the need for new and safety residential areas and industrial buildings have increased rapidly because of the increase in population. For doing this, one of the important solutions is to prepare landslide susceptibility maps to reduce the impact of landslides by determining the areas at risk. Because combination of many factors affect landslide occurrence, the implementation of multi-criteria evaluation systems (MCE) are useful. The purpose of this research is to model landslide susceptibility using remote sensing, geographic information system and analytical hierarchy process (AHP) techniques in Lajimrood watershed. Also, the developed model was carried out in adjacent test site (Varaki catchment) to assess model accuracy. At first, 32 landslides determined and some data gathered from Mazandaran province watershed management office and field works. The location of these landslides recorded using Global Positioning System (GPS) and transformed to map in GlS environment. The effective factors were selected with questionnaire analysis and their layers produced in Arc/View 3.2 software. The weights and rates of different classes of the effective factors prepared using analytical hierarchy process, the final model developed in GIS environment to map hazard susceptibility. Then, this model accomplished in Varaki catchment and crossed with landslide inventory map to analyze developed model accuracy. The results shown 74% happened landslides in test site, located in very high and high hazard category that proved high accuracy of model.

War and conflict in Africa has roots in the colonization of this continent. In order to fulfill their own predetermined goals, the colonizers attempt to divide the continent and establish separate governments which had no conformity with the inter-border nations.Consequently, after gaining independence these “states” faced many problems such as artificial borders, weak governments, poor interaction between the governments and civil society, emergence of a pro-colonialist political elite, and weak economic structure and political institutions which in turn gave rise to domestic and regional conflicts, frequent coup detats and root causes of the crisis. The Cold War and militarization of the ruling regimes were among other factors of the continuation of crisis. The existence of the crisis of accumulation and governance and the lack of attention of the rulers to the demands of their nations led to legitimacy crisis in the majority of African regimes which itself is another reason for the conflicts in the continent. The presence of conflicts in this continent took a heavy toll such as mortality, homelessness, abuse of human and economic resources, and the like. By exploring the differences in the formation of governments in the two continents of Africa and Europe through statistical and analytical method, the present research attempted to know the main contributory factors in the emergence of conflicts in the African continent and identify their varieties.

According to definition of European Environment Agency, drought is a recurrent feature of climate and it cans occur in any range of rainfall, any area and any season (Hughes, 2002, 1572). That is one of the natural dangerous enemies of mankind.Therefore, recognition, review, analysis and forecasting the occurrence of drought is vital for some of human activities. In this study, in addition to analysis of drought (Frequency, Intensity and Strength indices), the repetition of drought spells have been forecasted over Urmia Lake Basin located in the North Western region of Iran. In order to do this, first, the annual precipitations have been spatially normalized in the course of period 1961_2005 to make use BMI Index. After that, the intensity of wet and dry periods was categorized to develop PDRI empirical index in two classes. At the next stage, the time series were applied for drought prediction through SARIMA family models of relevant monthly precipitations forecasting have been implemented by means of SPSS software and according to the most appropriate models for the next 24 months (to 2007). Finally, corresponding the predicted sums, the severity ranks of humid or drought years have been determined. Our study showed that annual precipitation rate is normal approximately with increasing trend over mentioned Basin in 2006-7. On the other hand, the chief of humid and drought years have been interrupted with durability less than a year.

In order to evaluate the drought trend in Zayandehrood sub basins monthly precipitation maps of the Zayandehrood basin for 588 months (1951-1999) have been prepared using kriging method. Based on these maps Standard Precipitation Index has been calculated and considered as drought indicator for the sub basins. A nonparametric Mann-Kendal trend analysis applied to precipitation series and SPI series separately. For precipitation time series none of the basins showed significant negative trends. At the same time in February, March, May, and June significant. positive trend detected. The March Precipitation in All sub basins of Zayandehrood has significant positive trends. A nonparametric Mann-Kendal trend analysis for SPI showed that in Jun, April, May, July, August, October, November and December none of the basins showed significant trends.The highest significant trend appeared in March, February and June. All sub basins have significant trend in March.

Every year a huge amount of stones and according the investment on them are and wearing out of the building stones in the metropolis of mashhad. Marblite stones and granite has a durable resistance against the weathering among the building stones use for the external walls. The type of weathering in stones facades of the city of mashhad is physical (mostly frost action). In other word physical weathering surmounts chemical weathering. It has been also cleared that the rate of weathering in building stones used in facades in the city of mashhad facing to the south is more than the other geographical directions.