中文摘要：

研究400mm等雨量线的时空变化在应对全球气候变化对区域生态环境和社会经济的影响具有科学价值。对中国大陆1951—2012年752个站点的逐年降水观测值，用反距离空间加权法插值获得中国大陆62a年均降水分布图，采用加权平均方法获取62a400mm等降水量线。研究表明，中国大陆1951—2012年的年均降水量总体呈下降趋势，年下降速率为6.77mm/a;1951—2012年期间，中国400mm等降水量线整体加权平均位置为东经105。56、北纬37。5r,总体东移6。42、总体北移2。26、400mm等降水量线具有明显分段特征，其中东段是在1975年后才出现的，此后37a400mm等降水量线向东推移了近1850km。

英文摘要：

It is of great scientific significance to study the spatial and temporal changes of 400 mm precipitation contour in order to deal with the impact of global change on regional ecological environment and social economy.For annual precipitation observations recording from 752 sites in China from 1951 to 2012 year,the annual precipitation distribution in China mainland during 62 years is obtained by inverse distance weighting interpolation method,and the weighting average method is used to obtain the 400 mm precipitation contour during 62years. The conclusions are as follows: ( 1 ) the annual average rainfall of China from 1951 to 2012 shows a downward trend,and the annual decline rate is 6. 77 mm/ a ; (2)from 1951 to 2012 year, China 400 mm precipitationcontour overall weighting average position is 105°56,E ,37 has a moving tendency to east and north,overall eastward 6 042r, overall northward 2 026r; ( 3 )the 400 mm precipitation contour has distinct characteristics of segmentation. The eastern part is appeared after 1975, since then 37 years the 400 mm precipitation contour move to the east nearly 1 850 km.