关键词: 欧洲云杉, 欧洲云杉, 氮素, 根系形态, 生物量, 含氮量

Abstract: Based on the daily precipitation data of 86 stations in Jiangxi and the NCEP/NCAR monthly reanalysis data from 1961 to 2015, the Temporal and spatial distribution of autumn precipitation and anomaly circulation features in Jiangxi in the latest 55 years were analyzed by using the EOF, REOF, Morlet wavelet, linear trend, Mann-Kendall analysis and composite analysis methods. The results show that: the autumn precipitation in Jiangxi presented an upward tendency during the 55 years. Abrupt changes appeared in 1981, 1984 and 1987, respectively. There were a long changing period of 12-14 and a short changing period of 2-4 years. The space filed of autumn precipitation in Jiangxi was divided into the overall consistency, the south-north inverting type and the south with north-middle inverting type, and the generally consistent type was the main form of it. Spatially, it could be subdivided into the following five regions: mid-west of north Jiangxi, south of Jiangxi, west of central Jiangxi, east of north Jiangxi and mid-east of central Jiangxi. Autumn precipitation was increasing in mid-west of north Jiangxi, west of central Jiangxi and mid-east of central Jiangxi, while decreasing in south of Jiangxi, and stable in mid-east of central Jiangxi. Different times of abrupt changes appeared in all five regions during the 55 years in different years, and abrupt changes appeared in early 1960s in the region of south of Jiangxi, west of central Jiangxi, and east of north Jiangxi. There was a changing period of 2-4 years in all the five regions and a changing period of 4-6 years in several regions. The longest changing period was 14 years. In addition, the circulation features of flood years and drought years showed that when the trough in the east of Europe at 500 hPa became stronger, and Jiangxi Province was controlled by northwest wind, besides, northeast anomaly wind at 850 hPa controlled Jiangxi and weak southwest anomaly wind appeared over Jiang-Huai Basin resulting in precipitation in autumn less than that in the same period of normal years in drought years of Jiangxi. The circulation pattern were contrary to the patterns mentioned above in flood years of Jiangxi resulting in precipitation in autumn more than that in the same period of normal years.