上海市郊林带的防风效应分析

用夏季台风影响期间上海市东南沿海南汇海塘边林带防风观测资料和冬季冷空气影响时北面嘉定浏岛林带防风观测资料分析上海市郊林带的防风效应。结果表明：无论是夏季台风还是冬季冷空气影响时，林带的防风效应是非常明显的。台风影响期间，离林带越近，减风效应越大，随高度增加，减风效果减小；而远离林带处的减风率较小，随高度升高，减风效果增大；而且林带的减风效应还与风速有关，风速越小减风效果越明显。冬季由于受两条交叉林带的影响，两个测点的防风效应基本一致。试验结果可为上海市郊林带布局提供参考。

Analysis of Effects of Shelterbelt in Shanghai Suburb

Based on data of wind speeds in shelterbelt during summer typhoon season in Nanhui and winter season in Jiading, the shelterbelt effects were analyzed. The results showed that the windbreak effect was very remarkable both in summer and in winter. During summer typhoon season, the nearer to the shelterbelt it was, the bigger the windbreak effect was. Along with altitude increase the windbreak effect minished in the near of the shelterbelt, while the windbreak effect increased in far shelterbelt. The windbreak effect of the shelterbelt was related to the wind speeds. The smaller the wind speeds were, the more evident the windbreak effect was. The windbreak effect in two sites got same results in in winter due to the cross of the two shelterbelts. The results would offer reference for distribution of the forest .