气候变化对长江中下游地区水稻产量的影响

Effects of Climate Change on Rice Yield of the Middle and Lower Reaches Region of the Yangtze River

为了揭示区域气候变化对长江中下游地区水稻产量的影响及水稻相对气象产量波动的原因,采用统计分析方法和小波变换方法分析了近60年来长江中下游地区水稻产量、水稻生长季内平均气温、降水量、气温日较差以及≥10℃活动积温的年际变化以及水稻产量与区域气候变化之间的时频结构特征.结果表明,近60年来长江中下游地区水稻产量呈波动增长趋势;20世纪80年代以后水稻生长季内平均气温升高、≥10℃活动积温增大,降水量减少趋势不明显,气温日较差呈显著下降趋势.水稻产量和区域气候变化均存在年际和年代际尺度变化周期,且两者之间的时频特征存在一定的相似性;交叉小波分析表明,水稻产量与区域气候变化之间存在2～4a、6a、8a、12a和14a尺度的共振频率,且多以正相关关系为主,但在局部时域中也存在不同频率尺度的负相关,两者之间的相关关系和相关程度随振荡频率尺度的不同而不同.长江中下游地区水稻产量波动与区域气候变化密切相关,气候变暖导致热量条件改善对水稻产量的影响大于降水量减少对水稻产量的影响.

To reveal the impact of the regional climate change on rice yield of the middle and lower reaches of the Yangtze River, and to understand the reasons for rice relative meteorological yield fluctuations, statistical analysis and wavelet trans form were used to analyze time and the frequency variation features of rice production, the average temperature, precipita tion, diurnal temperature, active accumulated temperature of the Yangtze River region in the past 60 years, and the timefrequency structural features between rice production and regional climate change. The results showed that rice yield of the middle and lower reaches of the Yangtze River region in the past 60 years had fluctuations in the growth trend. The average temperature and the active accumulated temperature increased during the growing season. The reduction of precipita tion was not obvious. Diurnal temperature appeared to decrease significantly. Between rice production and climate change, there were periodic characteristics of interannual and decadal changes. The timefrequency characteristics was certainly similar between the two. Crosswavelet transform results showed that between rice production and climate change, there were the res onance frequency of the different scales, like 24a, 6a, 8a, 12a and 14a. There were more positive correlation between the main, but in the local time domain there was a negative correlation of different frequency scale. The two relationship and relevance were different, varying from oscillation periods scale. It was believed that rice yield fluctuations of middle and lower reaches of the Yangtze River was closely related with the climate change. The periodic feature was obvious, and the effect of the improvement of heat condition on increasing production was much more than the impact of reducing precipitation.