阿勒泰地区冬季降雪的集中度和集中期变化特征

摘要

利用1961～2010年阿勒泰地区冬季台站降水资料，计算并分析了阿勒泰地区降雪集中度和集中期的时空变化特征。结果表明：降雪集中度（PCD）和集中期（PCP）能够定量表征降雪量在时空场上的非均一性。阿勒泰地区降雪平均集中度为0．27，平均集中期为第7．8候（12月上旬）。平均集中度和集中期空间分布不均匀，东部的降雪集中度和集中期较西部大。Morlet小波分析表明，阿勒泰地区降雪集中度和集中期存在各自的年际尺度周期变化。通过降雪量与集中度和集中期的合成分析表明，多雪年集中度较少雪年偏小，集中期较少雪年偏早。%Based on observed winter precipitation data in Altay region from 1961 to 2010,the temporal and spatial variations of precipi-tation concentration degree (PCD)and precipitation concentration period (PCP)were caculated and analyzed.The results show that the snow PCD and PCP could characterize quantitatively the heterogeneity of snowfall in space and temporal field.The averaged PCD in Altay region was 0.27,and the averaged PCP was the 7.8 pentad (in early December).The averaged PCD and PCP distributed une-venly,and they were higher in east than that in west region.The periods of PCD and PCP in Altay region were given out by Morlet wavelet transformation,which showed there was a significant periodic change of PCD and PCP at inter-annual scale.The PCD in snowy years was less than that in less snowfall years,and the PCP in snowy years was earlier than that in less snowfall years.