长沙近41年气候变化对双季早稻产量的影响

为了诊断分析气候变化对长沙水稻产量的影响是正效应还是负效应，利用长沙市4个人工观测站1971—2011年逐日气温、降水量和日照时数等资料，采用趋势系数、相关系数、Mann-Kendall检验等方法，对长沙双季早稻生长期的气候变化特征及气象产量与其生长期气象因子间进行诊断分析。结果表明：（1）影响长沙早稻产量的关键气象因子依次是：5月低温、生长期最高气温、生长期降水量、灌浆乳熟期最高气温、生长期日照时数、5月日照时数、5月最高气温、5月平均气温及洪涝；（2）5月低温强度指数Ij与气象产量呈极显著负相关，对早稻产量有明显不利影响；生长期降水量与气象产量存在显著负相关，降水量太多不利于高产；（3）近41年来，早稻生长期最高气温、5月平均气温、5月最高气温呈极显著增加态势，生长期最高气温与气象产量呈极显著正相关，5月平均气温、最高气温、灌浆乳熟期最高气温与气象产量呈较显著或显著正相关，增温十分有利于早稻高产；（4）生长期日照时数与气象产量呈显著正相关，日照时数多对早稻高产有利；（5）近41年来，早稻气象产量呈弱下降态势，20世纪70年代末到80年代中期大幅增长，2004—2008年小幅增长，得益于生产力水平和早稻品种的提升以及十分有利于早稻增产的气象条件；20世纪80年代中期到90年代中期多为负值及2009年连续3年负值，在于气象条件对早稻增产无贡献。气候变化对长沙早稻产量的影响总体呈正效应。

Effect of Climate Change on Early Rice Yield in Recent 41 Years of Changsha

In order to analyze whether the effect of climate change on rice yield of Changsha is positive effect or negative, using the data of daily temperature, precipitation and sunshine time, etc. from 4 observatories in Changsha during 1971-2011, the author took the tendency coefficient, correlation coefficient, Mann-Kendall inspection methods to analyze the Changsha double season early rice growth period of climate change and its output growth characteristics of meteorological between meteorological factors. The results show that: (1) the key meteorological factors that influenced early rice yield of Changsha were low temperature in May, the growth period highest temperature, precipitation, highest temperature in milk and heading stage, sunshine duration, growth May sunshine time, and highest temperature, the average temperature and the flood in May. (2) Low temperature intensity index Ij in May and meteorological yield had significant negative correlation, which had adverse effect on early rice yield in May; there was significant negative correlation between precipitation and meteorological output growth; too much annual rainfall worked against high yield; (3) In recent 41 years, there was significant positive relationship among rice growth period highest temperature, the average temperature in May; the highest temperature in May was very significant increase trend, the highest temperature and meteorological output growth was very significant positive correlation, May the average temperature and the tallest temperature, grouting highest temperature and meteorological culm production was a significant or significant positive correlation, raising temperature was very helpful in the early rice yield; (4) The sunshine duration and meteorological output growth was a significant positive correlation, sunshine time for early rice yield more advantageous; (5) In recent 41 years, rice yield was weak down the trend, the 1970s to the 1980s growth sharply, from 2004 to 2008 a modest growth, thanks to productivity level and early rice varieties of ascension and early rice yield was very helpful in meteorological conditions; in the mid 1980s to the mid 1990s much negative in 2009 and 3 consecutive years of negative value and meteorological conditions for early rice yield were no contribution. Climate change on early rice yield affected the total of Changsha positively effect.