青海同德近50年气候与草地畜牧业生产的关系

The influence of climatic change on pastoral livestock production in Tongde county,Qinghai province

通过分析青海省同德县气候变化特征及其对草原生态环境的影响,发现同德地区气候变化的显著特征是:年平均气温和冬季、秋季、春季、夏季升温趋势分别为0.37、0.69、0.23、0.21、0.18℃/10年;年高温(≥25.0℃)时间以0.53 d/10年趋势增加;年低温(≤-30.0℃)时间以0.42 d/10年的趋势减少;日平均气温稳定通过10℃的终日延长1.9 d/10年;1987年以来同德相继出现14个暖冬,是近45年来最暖的时期。并由此引起无霜期延长,积雪、冰雹、雷暴、大风、沙尘暴日数的减少,草地干燥指数和草地蒸发力呈逐年上升趋势,年降水量以10.5 mm/10年的趋势减小,20世纪90年代是降水量最少的时期。气候变化一方面使同德地区草原的生态环境有所好转,另外也是近几年蝗虫泛滥的主要原因之一。当前存在的草原退化现象主要应归咎于不合理的人为活动。

The temperature elevation tendencies w in annual mean, winter, autumn, spring, summer were 0.37, 0. 69,0. 23,0. 21 and 0.18 ℃/10 a,respectively. Changes in duration length for temperature above 25 ℃, below --30 ℃ and stable above 10 ℃ were 0.53, --0.42,and 1.9 day/10 a; There had been 14 warm winters appeared since 1987, forming the warmest period during last 45 years. As a result, frost-free period was lengthen, days for snow, hail, thunderstorm, gale and sand storm occurrence were shorten, dry index and evaporation went up. Declined annual precipitation with rate of 10.5 mm/10 a was observed, caused 1990＇s was the precipitation least period. The climate change had affected abiotic factors and caused grasshopper disaster occurrence. Human Being activity was considered likely a major factor to cause grassland degradation.