Abstract:In this paper, the filter analyses are made on the energy and heat fields in the process of spring cold waves over North China. The characters of the energy and heat distributions on different scales before and during the cold-wave process are given, along with their relationships with the activities of cold waves.

Abstract:Two statistical parameters, skewness and kurtosis are introduced to investigate particle distribution. A quantitative method is formulated to testify the fitting goodness to Γ-spectra. A quantitative criterion named 'Deviation Cofficient' is presented to express the natural deviation from exponential spectra under the Γ-spectra assumption and according to the criterion a classification is developped.

Abstract:In this paper,four methods evaluating climate change are intercompared. It is evident that the Maximun Anomaly Method is easier to operate and to obtain the better results, The long series of the abnormal year with widespread drought or flood and hot or cold in Guangdong Province are derived and evaluated with this method.

Abstract:In this paper, the potential evapotranspiration and agricultural water demand are calculated, and the agricultural water demand is compared with water resources in Beijing. The results indicate that water resource can meet the requirement of agriculture in normal climatic years, although a deficiency would appear in drought years. At present, a higher potential could be found of water saving in agriculture over Beijing areas. If the potential is fully taken into account and the necessary measures are carefully adopted, the water could meet the requirement by agriculture even in drought years.

Abstract:Based on the principles of the drought severity model of developed by W.C.Palmer, a revised model of drought severity for the northwest Loess Plateau has been established in this paper. And the model has been used to analyse the drought character of this region. The results proved that this model is a good tool for drought researching on the region.