中国历史气候记录揭示的千年干湿变化和重大干旱事件

对中国历史气候记录的研究表明：准周期性是过去1000年间中国东部各区域的干湿气候变化的基本特征；各区域间主要周期变化的位相差异，表现为降水的空间分布格局（如南涝北旱、北涝南旱等分布型）随时间的变化；1000年来干湿气候发生过多次十年和百年尺度的突变，降水的突变对农业生产会有明显影响。过去1000年间多次出现过大范围的持续时间3年以上的严重于旱事件，其严重程度多为最近50年所未见，因此，在过去1000年的气候变化历程中，最近的50年沿属于气候条件较好 的时段，但对未来出现气候突变和重大气候灾异的可能性应予以警惕。

VARIATION OF DRY-WET CLIMATE AND SEVERE DROUGHT EVENTS AS REVEALED IN THE CLIMATE RECORDS OF CHINA OVER THE PAST 1000 YEARS

Based on the historical climate records of China, the study reveals that quasi periodicity is the basic feature of regional dry-wet climate happening in the eastern part over the past 1000 years; difference in the phase of major periods on dry-wet between the north and south of eastern China is displayed in the time-dependent pattern of rainfall, i.e., a drought in the north and a flood in the south and v.v.; multiple abrupt appearances of dry and wet climate on decadal and century scales occurred in the last 1000 years, exerting great impacts on agriculture; discovered large-scale severe droughts each lasted > 3 years, analysis shows that many of the drought events were more severe than what has been recorded in the recent 50 years, a time interval that is more acceptable compared to other periods in the past 1000 years. Obviously, we should be alert to future climate abrupt change and major disastrous situation.