The Climate Change In QinHuangDao In Recent 45 Years And Its Impact On Agriculture

Under the major background of global warming, the regional climate in Qinhuangdao is just changing obviously. Because of greenhouse effect, rainfall decreasing, and the serious drought in resent years, the developing of economics and agricultural environments has been influenced by them. Therefore, learning the rules of climatic change in Qinhuangdao is much significant for improving level of short-term climate prediction and instructing local farm production and industrial production.According to the data from temperature and rainfall of five observing stations from 1960 to 2005 in Qinhuangdao.the statistics of some climatic factors such as mean temperature, mean maximum temperature, mean minimum temperature, precipitation are gathered in the light of year and season, their change for 45 years have been analyzed carefully, the results show that recent 45-year mean annual temperature and mean seasonal temperature present a tendency to rising, especially for late 15 years. The trend of annual temperature variation is in tune with that of each seasonal temperature variation, but warming range is distinct clearly, the largest is in winter. Mean annual maximum temperature has been going up, more notable since 1988; warming years occur continuously in winters after 1987,the largest of mean winter maximum temperature for late 45 years is in winter 2001. Mean annual minimum temperature has been rising, rapidly since 1988 that change keeps 12 years until 1999;the biggest of warming range is also in winter. Tendency to rising and changing range on minimum temperature are more than those of maximum temperature, that is to say, there is conspicuous warming trend during the night, but that is weak in the daytime, diurnal range of temperature is decreasing gradually. General trend on rainfall tend to decrease in this locality, that circumstance has been more obvious after 1990s, it represent a serious drought stage since being weather observatory record. The trend of rainfall decreasing is more and more clear in winter, and the precipitation is negative departure afterl999, precipitation displayed most shortage in this term, the trend of rainfall decreasing in other three seasons does not pass through significance test. Dates of micro-precipitation (more than or be equal to 0.1millimeter) appear decreasing trend, being 1.6 days of raining has been decreased each 10 years, dates of rainfall in summer are outstanding reduced, dates of rainfall in every grade is also becoming more deficient, moreover, the most reducing is dates of heavy rain, the intensity and the frequency on extreme rainfall are all reduced, the longest successive time of non-rainfall is increased.Hours of sunshine in Qinhuangdao appear decreasing trend, being noticeable change in stages. Annual evaporation capacity obvious decrease, and that in the four seasons is the same, more marked in spring and in summer. Relative humidity change indistinctively, and on the whole, it present tendency towards going down, especially in spring, in autumn, and in winter. Accumulated temperature in Qinhuangdao increase, the first frost delays, the latest frost moves up, and frost-free period extend.The drought frequency in Qinhuangdao is becoming enhancing gradually, and be the same in intensity, severe drought years has taken place since late 1980s.spring drought and winter drought have high probability to happen, disater degree of summer drought is higher than that of spring drought and autumn drought, the number of flood are less than that of drought, but the calamities caused by flood have very serious degree, however its frequency has reduced little by little with intensity weakened. Hails often come up between 12 o'clock and 20 o'clock, 54% of those emerge from the period of 15 o'clock to 17 o'clock afternoon, dates of hails has began decrease by degrees since later 1990s, all kinds of cool injury and freeze injury show a decreasing trend, the numbers of microtherm and continuous rain become less increasingly. Dry-hot wind encounter frequently before 1980,and it reduce rapidly after 1984.The temperature rise in Qinhuangdao would benefit agriculture, but temperature rise will make crops growth speeding up as well as making birth period cutting short, so the single output may decrease, the productive potentialities brought about by local climate are likely to come down. The temperature rise may speed up sea level elevating, and furthermore lead to salinization for farmland in Qinhuangdao; the quality of soil would descend, and reduce on the arable land. The decrease of Precipitation get soil moisture content becoming dry, it can threaten agricultural production seriously. Global warming, especially the sharp warming in winter, strengthen the probability of plant diseases and insect pests. Climatic change makes crops yield increasing, but there is a great change inter-year. Meteorological disasters often take place since 1980s, years of crop failure occur frequently.Based on observational data of numerous sites for many years, the long-term change on several kinds of climatic elements have been studied systematically, the cases of extreme weather and climate and the changing trend about meteorological damage in Qinhuangdao are also analyzed, the effect of climatic change on agricultural production has explored, Until now, it is most complete and systemic writing about the study of climatic change in that locality, so that, this effective research can offer the important reference for adapting to climatic change, absorbing what is useful and rejecting what is harmful , disaster prevention and reduction in that area, The research result will be increasingly used in weather forecast and the agro-meteorological service.