杭州气候变化趋势分析及其对农业的潜在影响

Changing Trend Analysis for Climate Events in Hangzhou and the Potential Effect on the Agricultural Production

应用杭州市7个国家气候站建站以来的逐日气象观测数据,通过计算与温度、降水、相对湿度、日照及作物生长期相关的气候指标,构建长时间序列,通过趋势分析法、显著性检验方法以及气候突变检测法,对杭州基本气候状态与气候事件的发生与演变特征进行分析。结果表明,(1)各站均表现为极显著的增温趋势;年降水量有所增加,但仅萧山通过显著性检验;年平均相对湿度除杭州南部的建德和淳安外均呈现极显著的减少趋势;年日照时数均表现为极显著的减少趋势。(2)杭州中部和东部的富阳、杭州、萧山的极端高温事件有逐渐加剧的趋势,表现为年极端最高气温升高与高温日数增加,大多数站点表现出高温初日显著提前与高温终日延后。极端低温特征均显著缓解,而且各站点活动积温与生长期长度均有所增加。(3)杭州年降水日数有所减少,而简单降水强度显著增加,即降水变得更为集中。各等级降水中,小雨日数显著减少,而暴雨日数显著增加。从季节降水来看,春季小雨和中雨日数显著减少;夏季暴雨日数增加;冬季中雨日数普遍增加。结合杭州本地特色作物类型,展开气候变化对农业生产潜在影响的讨论,研究结果可以为合理利用气候资源,趋利避害提供科学的数据支撑。

This research takes Hangzhou as a case study in analyzing the changing features of the climate conditions and climate extremes under global warming.The data applied in this paper are daily average temperature,highest temperature,lowest temperature,daily precipitation,relative humidity and sunshine duration from 7 national observatories within Hangzhou boundary.The trend analysis,the significance test and the mutation analysis methods are used to detect the changing trends of the climate features.Results show that,(1)all of the stations have showed very significant warming trend.The annual mean precipitation has increased in general,however,only in Xiaoshan that the increasing trend has passed the significance test.The annual mean relative humidity has significantly decreased in most stations,apart from Jiande and Chun’an.The yearly sunshine duration has showed significant decreasing trend in all of the stations.(2)When concerning the high temperature features,there is a significant intensifying trend in the high temperature extremes in the observatories including Fuyang,Hangzhou and Xiaoshan,which are located in the middle and east part of Hangzhou city,both of the extreme high temperature and hot days have showed obvious increasing trends,and Xiaoshan is the most prominent in the changing trends among all of the stations.There is a significant advance in the beginning date of high temperature in all of the stations,Lin’an shows the most obvious trend in advancing,however,only in Xiaoshan station which shows a significant trend in the postponement of the terminal date of high temperature.When concerning the low temperature features,there is a very significant mitigation trend in the low temperature extremes in each of the stations,especially in Fuyang.According to the growth period features of thermophile crops,the active accumulated temperature and the length of growth season have increased in all of the stations,and it is the most obvious in the increase of the heat resources in Xiaoshan.(3)There is a general decrease in the rainy days,but it does not pass the significance test.However,the simple daily precipitation intensity has increased significantly,implying the more intensified daily precipitation.The number of light rain days has decreased significantly,while the number of rainstorm days has increased significantly in almost all of the stations.As for the seasonal precipitation,there is a significant decrease in the spring rainy days,which is due to the decrease of the light and moderate rainy days.Besides,the number of rainstorm days has increased significantly in summer and the moderate rainy days has increased in winter.The potential effects of climate change to the featured agricultural products are discussed,the results of the paper can provide a sound data support for the understanding of the climate change trends,making rational use of climate resources,as well as seeking climate advantages and avoiding disadvantages in Hangzhou.