1956—2010年辽西地区玉米气候适宜度时空分布特征

以玉米气候适宜度模型及辽西地区4市8站近50 a(1956—2010年)逐日气象数据为基础,利用空间插值、经验正交函数分析方法(EOF)和小波变换分析方法对玉米全生育期及各主要生育时期气候适宜度的时间变化和空间分布特征进行分析,研究气候变化过程中辽西地区农业气候资源对玉米生长的适宜程度的变化特征。结果表明：1)近50 a,辽西地区玉米全生育期的降水、日照及综合气候适宜度呈逐年下降趋势,除开花期综合气候适宜度呈上升趋势外,播种、出苗、成熟期综合气候适宜度均呈下降趋势；2)在空间分布上,辽西玉米全生育期的温度适宜度、日照适宜度,播种、成熟期的综合气候适宜度分别表现出由南向北、由西向东、由西向东南和东北、由东北向西南递增,而出苗期综合气候适宜度表现为由西北向东南和东北递减；全生育期的降水适宜度、综合气候适宜度和开花期的综合气候适宜度由北向南均呈现“低－高－低－高”的带状分布特征,播种、出苗和开花期限制因素分别为降水、日照和日照；3)EOF 分析发现,辽西地区玉米全生育期综合气候适宜度距平百分率在空间上表现为西南向东北微幅递减；在时间上,小波分析发现辽西玉米综合气候适宜距平百分率第1特征向量的时间系数存在14~30 a、8~14 a、3~7 a 的3类尺度的震荡周期。

Spatio-temporal distribution characteristics of climatic suitability degree of maize in Western Liaoning Province from 1956 to 2010

Under global climate warming and drying, temperatures have increased to varying degrees around the world. Global warming has caused significant changes in agro-ecological environments, of which maize yield and quality have been found to be heavily influenced by meteorological factors. Therefore the analysis of the suitability degree to climate change of maize during growth period could provide an important guide for increasing agricultural production. Basis on a climatic suitability degree model for optimal maize production, daily meteorological data for 1956-2010 from eight meteorological stations in four cities in West Liaoning Province were analyzed. The analysis included the spatial and temporal distribution characteristics of climate suitability degree during the whole growth period and each individual growth stage of maize using spatial interpolation, Empirical Orthogonal Function (EOF) analysis and wavelet transformation analysis. The results showed that: 1) The suitability degrees of precipitation, sunshine and integrated climate followed a declining trend during the maize growth period from 1956 to 2010. The suitability degree of integrated climate dropped at sowing, emergence and maturity stages but rose at flowering stage. 2) The suitability degrees of both temperature and sunshine during the whole growth period of maize and the suitability degree of integrated climate during sowing and maturity stages tracked an increasing trend from south to north, from west to east, from west to southeast and northeast, and from northeast to southwest in West Liaoning Province. However, the suitability degrees of temperature and sunshine at emergence stage were in contrast to that of sowing, with a general declining trend from northwest to southeast and northeast. The suitability degrees of precipitation, integrated climate during the whole growth period of maize and integrated climate during flowering followed a “low-high-low-high”zonal distribution from north to south. The constraint factors during sowing, emergence and flowering were precipitation, sunshine and sunshine. 3) EOF analysis showed that the percentage anomaly of suitability degree of integrated climate during the whole growth period of maize in West Liaoning Province generally slightly declined in space from southwest to northeast. Wavelet transformation analysis suggested the time coefficient of first feature vectors of integrated climate suitability degree at 3 scales of oscillation period ― 14-30 years, 8-14 years and 3-7 years.