Climatic studies in North East England

Abstract

This thesis applies a two-dimensional analysis to three problems. Each problem utilizes the daily observations of sunshine duration and maximum temperature recorded at Durham Observatory from July 1937 to June 1962.The analysis is termed 'two-dimensional' since it classifies meteorological data according to time of year and mean daily wind direction. This procedure was initially devised to describe, in Part 1, the effects of a local climatic phenomenon which is associated with wind from a particular direction. Parts 2 and 3 apply the two-dimensional analysis to problems of zonal interest. Part 1 describes the effects of the haar upon daily sunshine duration and maximum temperature. It observes that these effects are unexpectedly weak but it stresses that this observation may be caused by a general failure of two-dimensional analyses to detect rare, intermittent phenomena such as the haar. The second part of the thesis describes and explains the variations of daily sunshine duration which are detected by the two-dimensional analysis. These variations form the basis of a three-fold subdivision of 'rates of sunshine production' within air masses. Part 3 correlates corresponding daily sunshine durations and maximum temperatures on a monthly basis. It observes a two fold subdivision of the year. The summer period, including the seven months from March to September, is characterised by positive correlations which are pronounced on days with winds from the continent and weak on days with south west winds. The elements are usually uncorrelated in winter (the remainder of the year) but on days with south west and west winds in January they are negatively correlated. These observations are explained in terms of the seasonal changes in the relative magnitude of the components of the radiation balance. The conclusion discusses the general applicability of the two-dimensional analysis within air mass climatology. It considers that this applicability is severely restricted by the complexity of air mass movement.