Abstract:

Abstract: This paper uses the data of average temperature that came from 12 weather stations and from 1960 to 2007 to calculate the frequency of abnormal average temperature in Weibei dryland, and analyze the distribution characteristics and evolution rules of abnormal average temperature. It also analyses the influence on agriculture production. The research shows that: (1) Temperature has been on the rise in the past 48 years, which is consistent with the trend of global warming .The warming levels in different seasons are sharply different. Among the four seasons, winter warming is the most evident, followed by spring. Summer warming is not so apparent. With the rising of temperature in winter, the safely growing area of wheat in winter will move further to the north. What's more, the drought will be more serious as the evaporation increases. (2) Abnormal warming phenomenon always happened in August since 1960 in Weibei dryland, and never happened in June. Abnormal chilling often appears to be in February. May is the only month that has not witnessed exceptionally low temperature. (3) The seasonal warming leads to the rise of winter temperature. It increased soil moisture evaporation of farmland in winter and in the meantime also makes across-winter pest eggs and pupas’ mortality decrease. Therefore, it tends to be more difficult to control pest. These are the adverse effects of rising temperature. (4) Weibei dryland’s abnormally high temperature has been more obvious since 1990s. The frequency of abnormally high temperature in autumn is stable. And the frost damage to crops has been reduced as the abnormally low temperature in winter reduced obviously.