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641.
THE CORRELATIONS BETWEEN SST AND SUMMER PRECIPITATION OVER EASTERN CHINA AND THE EFFECT OF THE SST ANOMALY IN THE SOUTH CHINA SEA ON THE SUMMER MONSOON AND PRECIPITATION
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By use of the method of empirical orthogonal function resolution a study is made of the distributionpatterns of summer rainfall percentage anomalies over eastern China with the result that such anomalies areable to reflect the relative amount of local precipitation.Then the correlations are obtained through calcula-tion between the patterns and the January and June global SST,indicating key regions in association withChina's summer rainfall.On this basis,an 11-layer atmospheric circulation model by the U.K.Meteorol-ogical Office is used to simulate the effect of a weak SST anomaly of the South China Sea upon the summermonsoon circulation in China's mainland.Results show that‘attraction’is available for the Indian monsoonwith a warm anomaly of the SST and‘repelling’with a cold,representing one of the reasons for the anti-phase between the monsoons over the South China Sea and India.Such functions of SST anomalies have asignificant influence on summer rainfall over eastern China. 相似文献
642.
A microprobe study has been carried out on the chemical composition of tourmaline from the Yindongzi and Tongmugou stratabound Pb-Zn ore deposits, eastern Qinling, China. Tourmaline was analysed from a variety of rock types representative of its various occurrences associated with the ore bodies. All the tourmalines studied here belong to the schorl-dravite series. Most are of hydrothermal origin with Mg > Fe and Na > Ca. Some detrital cores of tourmaline have been recognized from their geometry and chemistry, with Fe > Mg. The chemical trends from core to rim in zoned grains suggest a multi-stage model for the growth of tourmaline and genesis of the ore bodies. The first stage was represented by a more Mg-rich hydrothermal fluid in the submarine hydrothermal system, producing Mg-rich tourmalines by selective replacement of clay-rich sediments close to the sediment-water interface. The second stage was dominated by Fe-rich hydrothermal fluid and resulted in overgrowth of Fe-rich tourmaline rims. This stage also led to the nucleation and growth of new tourmaline crystals and was responsible for the formation of the main massive sulphide orebodies. Finally, a further period of hydrothermal activity or a metamorphic event led to the formation of an additional rim of Mg-rich tourmaline. 相似文献
643.
The four most abundant minerals generally found in Euramerican bituminous coals are quartz, kaolinite, illite and pyrite. These four minerals were isolated by density separation and handpicking from bituminous coal samples collected in the Ruhr Basin, Germany and the Appalachian basin, U.S.A. Trace-element concentrations of relatively pure ( 99+%) separates of major minerals from these coals were determined directly by using instrumental neutron activation analysis (INAA). As expected, quartz contributes little to the trace-element mass balance. Illite generally has higher trace-element concentrations than kaolinite, but, for the concentrates analyzed in this study, Hf, Ta, W, Th and U are in lower concentrations in illite than in kaolinite. Pyrite has higher concentrations of chalcophile elements (e.g., As and Se) and is considerably lower in lithophile elements as compared to kaolinite and illite. Our study provides a direct and sensitive method of determining trace-element relationships with minerals in coal.Mass-balance calculations suggest that the trace-element content of coal can be explained mainly by three major minerals: pyrite, kaolinite and illite. This conclusion indicates that the size and textural relationships of these major coal minerals may be a more important consideration as to whether coal cleaning can effectively remove the most environmentally sensitive trace elements in coal than what trace minerals are present. 相似文献
644.