河西走廊东部初、终霜冻日和无霜期变化特征分析

为了引进适宜作物品种，合理调整种植结构，提高农业产业水平。利用1961—2014年河西走廊东部4个气象站初、终霜冻日（最低地温≤0℃）和年气温资料，采用气候诊断方法，对河西走廊东部初、终霜冻日及无霜期的变化进行了研究。结果表明，在时间变化上，初霜冻日显著推迟，终霜冻日显著提早，无霜期显著延长。初、终霜冻日和无霜期时间序列分别存在8~10年、9~11年和9~10年准周期变化。初、终霜冻日和无霜期均发生了气候突变。受海拔高度、地形地势和植被覆盖的影响，在空间分布上，初霜冻日为山区早于荒漠区早于绿洲平原区，终霜冻日为山区晚于荒漠区晚于绿洲平原区，无霜期为山区短于荒漠区短于绿洲平原区。初霜冻日、终霜冻日和无霜期与年气温和海拔显著相关。

Change Characteristics of First and Last Frost Date and Frost-Free Period in Eastern Hexi Corridor

The paper aims to introduce suitable crop varieties and reasonably adjust planting structure and improve agricultural industry level. Based on the data of the first and last frost date (the lowest ground temperature ≤0℃) and annual temperature of 4 meteorological stations in eastern Hexi corridor during 1961- 2014, change characteristics of the first and last frost date and frost- free period were studied by climate diagnosis analysis method. The results showed that the first frost date was significantly delayed, the last frost date was significantly advanced and the frost-free period was significantly prolonged in time variation. Time series of the first and last frost date and frost-free period had 8-10 years, 9-11 years and 9-10 years quasiperiodic variation respectively. The first and last frost date and frost-free period all had a climate abrupt change. On space distribution, because of the influence of altitude, topography and vegetation cover, the first frost date appeared in an order of mountainous area, desert region and oasis plain, while the sequence of the last frost date was in contrary. The frost-free period was the shortest in mountainous area, followed by that in the desert region and was the longest in oasis plain. The first and last frost date and the frost-free period were significantly correlated with the annual temperature and latitude.