Abstract: Based on the data of average daily temperature and annual extreme minimum temperature at 16 meteorological stations in the Urumqi-Changji region during the period of 1961-2009, this paper analyzes the spatiotemporal change and sharp change of the first day of daily mean temperature stabilized at ≤ 0 ℃ and ≥ 0 ℃, duration of average daily temperature ≤0 ℃, negative accumulated temperature in winter, average monthly temperature in January and extreme minimum temperature using the methods of Mann-Kendall test, three-dimensional and quadratic trend surface simulation and inverse-distance square weighting residual error revising based on GIS. The main results are as the follows: (1) The winter heat resources was quite different from different regions in the Urumqi-Changji region. Generally, the first day of daily mean temperature stabilized at ≤0 ℃was earlier in mountains than that in plains and valleys, but the first day of daily mean temperature stabilized at ≥0 ℃ was later in mountains than that in plains and valleys. The continuous duration of average daily temperature ≤0 ℃ was longer in mountains than that in plains and valleys, and longer in the eastern part than that in the western part of the Urumqi-Changji region. Affected by winter inversion, the negative accumulated temperature in winter, average monthly temperature in January and extreme minimum temperature were increased from plains to mid-mountain zone about 2 100 m a. s. l., and their maximums occurred at this altitude; (2) under global warming, winter heat resources was in a significant increase trend in the Urumqi-Changji region in recent 49 years, the first day of daily mean temperature stabilized at ≤0 ℃ was sharply postponed in 1994 , the continuous duration of daily average temperature ≤0 ℃ was sharply shortened in 2004, negative accumulated temperature in winter was sharply decreased in 1988, and the average monthly temperature in January and the extreme minimum temperature were sharply increased in 1973 and 2004 respectively. The increase of various winter heat elements before and after their sharp change was higher in plains than that in mountains, and higher in city-dense regions than that in peripheral regions. Effects of winter heat resources increase may be advantageous to agriculture and livestock production in the Urumqi-Changji region. Therefore, some managing and technical measures should be taken so as to promote the sustainable development of agricultural and livestock production.  

Key words: winter, heat resources, average temperature, extreme minimum temperature, spatiotemporal variation, sharp change, Urumqi-Changji region