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This paper analyses the temporal and spatial changes in the amount and variability of rainfall in Scotland. The sequential Mann-Kendall test reveals that total annual precipitation has increased across Scotland since the 1970s with increasing trends in variability beginning between the mid-1960s and the mid-1970s. Whilst temporally consistent increasing trends in precipitation totals prevail in the West, many weather stations in the East have experienced subsequent trend turning points in the following two decades, explaining the larger magnitude of the trends in western Scotland in recent decades. Trend analyses on six measures of rainfall variability indicate an increase in rainfall variability during the period 1961-2000, as measured by the intra-annual variance, the winter to summer precipitation ratio and the annual cumulative sum range, with decreasing trends observed in the number of dry days. Periodicities associated with the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation could explain the observed temporal variability of rainfall. [ABSTRACT FROM AUTHOR]

Groundwater and surface water pollution from nonpoint sources are problems of increasing concern. Nitrate transport is a crucial part in the whole process of nitrate loss. Previous methods for simulating the nitrate transport process usually involved solving complex advection–dispersion equations and required large amount of parameters and input data, which makes a model application expensive or invalid in terms of computation and data availability. The aim of this research is to develop a simple conceptual method to simulate the nitrate transport. In this paper, a simple conceptual method utilizing the distribution of nitrate loss against cumulative drainage to simulate the nitrate transport process is introduced. The concept and construction of this method are presented, and its applicability at different spatial scales is demonstrated. Results of model application at laboratory, pilot, and catchment scales show that this method has a good capability to simulate the transport of nitrate. Impact of spatial scales on parameters’ values is also discussed. Compared to conventional methods, this method requires fewer parameters, less computing time, and less input data. [ABSTRACT FROM AUTHOR]

Assesses the effects of anthropogenic degradation of natural vegetation cover on various climactic patterns in Sudan over several decades. Temperature, rainfall, sunshine duration and global radiation; Evapotranspiration; Effect of climatic modification on drought conditions.