青海湖流域牧草物候期对气候变化的响应

RESPONSE OF PASTURE PHENOLOGICAL PERIOD TO CLIMATE CHANGE IN QINGHAI LAKE BASIN

基于青海湖流域3个气象站点1961～2017年气温、降水及日照时数等气象数据,分析了1961年以来青海湖流域的气候变化特征。利用2003～2017年的牧草生育期观测数据,对返青、黄枯日期、生长季与气象因子之间的关系进行了统计分析。结果表明:1)近57a青海湖流域的年和四季平均气温均呈显著上升趋势,冬季的升温幅度最大;年和四季降水量均增加,夏季降水量增加最多;年和四季日照时数呈下降趋势,夏季日照时数下降最为明显。2)海晏牧草返青期以10d/10a趋势提前,刚察以9d/10a趋势显著推迟,天峻以4d/10a趋势推迟,在空间上表现出从东南向西北呈推迟趋势。黄枯期均表现为推迟趋势,推迟趋势海晏2d/10a、刚察10d/10a、天峻5d/10a,没有明显的经向和纬向特征。生长季均呈延长趋势,海晏11d/10a、刚察2d/10a、天峻1d/10a,在空间上表现出与返青期相同的走向。3)海晏牧草返青期主要受上年秋季(8～10月)降水量的影响,降水量每增加10mm,返青期提前2.4d;天峻与刚察牧草返青期与返青前≥0℃积温正相关,积温每增加10℃,返青期分别推迟1.2d和0.7d。4)牧草黄枯期主要受降水的影响,降水量每增加10mm,海晏、天峻、刚察黄枯期分别推迟1.3d、1.3d、0.5d。5)生长期受同期气温和降水增加的影响均呈延长趋势。

Based on meteorological data such as temperature,precipitation and sunshine hours of three meteorological stations in Qinghai Lake Basin from 1961 to 2017,and analysed the climate change characteristics ofQinghai Lake Basin since 1961.Based on the observation date of pasture growth period from 2003 to 2017,tostatistically analyse the relationship between the turning green,yellowing and withering date,growth season andmeteorological factors .The results show that：1）Nearly 57 years,the annual and seasonal average temperaturesin the Qinghai Lake Basin have showen a significant upward trend,with the largest temperature increase in winter;The annual and seasonal precipitation increase,and the summer precipitation increase the most;the annualand seasonal sunshine hours have showen a decrease trends,and the decline in summer sunshine hours is mostpronounced.2）The trend of the turning green date in Haiyan was advanced by 10d / 10a,and the trend of 9d /10a was significantly postponed in Gangcha. The trend of Tianjun was postponed by 4d / 10a, and the spaceshowed a trend that gradually postponed from southeast to northeast.The yellowing and withering date showed apostponed trend,and the trend was postponed 2d / 10a in Haiyan,10d / 10a in Gangcha,and 5d / 10a in Tianjun,with no obvious meridional and latitudinal features.The growth season showed a prolonged trend.The 11d / 10a in Haiyan,the 2d / 10a in Gangcha,and the 1d / 10a in Tianjun,showed the same trend in space as the turninggreen date.3）The turning green date of pasture in Haiyan was mainly affected by the precipitation in the autumnof last year（August to October）.The precipitation increase by 10mm for each time.and the turning green datewas advanced 2.4d;Positive correlation between Tianjun and Gangcha pasture turning green date and ≥0℃ accumulated temperature before the turning green date.For every 10℃ increase in accumulated tempetature,theturning green date was postponed by 1.2d and 0.7d respectively.4）The yellowing and withering date was mainlyaffected by precipitation.For every 10mm increase of precipitation,the Haiyan ,Tianjun and Gangcha were postponed by 1.3d,1.3d and 0.5d respectively.5）The growth period is prolonged because of the increase of temperature and precipitation during the same period.