摘要：
为明确西南地区气候变暖前后春玉米生长季内不利气象条件的时空演变特征,本文采用西南地区27个农业气象站点1981-2010年的发育期资料和66个气象站点的1961-2010年的逐日气象资料,分析气候变暖前后西南春玉米生长季内连阴天、高温、低温及水分盈亏发生的时空分布特征.研究结果表明:①西南地区春玉米生长季内,连阴天主要发生在出苗-七叶和七叶-抽穗阶段,变暖后发生频率分别平均增加12％和15％,但仅11％和14％的研究站点显著增加(P＜0.05);②高温天气主要发生在乳熟-成熟阶段,且主要集中在东北部地区,变暖后发生天数每生长季平均减少2.5d,23％的站点高温发生的天数显著减少(P＜0.05);低温天气在整个生长季均有发生,变暖后低温出现天数每生长季平均减少2.2d,其中七叶-抽穗阶段低温发生天数减少最为显著,56％的站点发生天数显著减少(P＜0.05);③水分亏缺主要发生在播种-拔节阶段,变暖后轻、中度水分亏缺发生频率分别增加6％和7％;春玉米各个生长阶段均受不同程度的水分盈余影响,但主要表现为轻度盈余,除西北部外,变暖后轻度水分盈余发生频率增加15％,播种-拔节和灌浆-成熟阶段21％和11％的研究站点轻度水分盈余显著增加(P＜0.05).总体来看,变暖后西南地区春玉米生长季高温、低温发生天数减少,对玉米生长有利,但连阴天以及水分盈亏发生频率增加,可导致玉米品质下降和产量减少.%We investigated spatial and temporal variations in adverse meteorological conditions during the maize growing season in Southwest China.Datasets covered observed phenological data from 27 agro-meteorological stations (1981-2010)and daily meteorological data from 66 meteorological stations (1961-2010).These data were used to calculate agro-meteorological indices such as successive overcast weather,high-temperature day,low-temperature day,water surplus and deficit index,indicating adverse meteorological conditions in the most recent 50 years.We found that successive overcast weather occurred frequently from emergence to seventh-leaf and from seventh-leaf to heading,and the frequency increased by 12％ and 15％,respectively after climate warming.A total of 11％ and 14％ of stations decreased during these two periods.Heat stress mainly occurred during the period from milking ripeness to maturity,which mostly centered in northeast of Southwest China.The number of days with heat stress decreased by 2.5 days after climate warming,with 23％ of stations decreasing.Low-temperature days occurred during the whole growing season,and the number of days with cold stress decreased by 2.2 days after climate warming,especially during from seventh-leaf to jointing when 56％ of stations decreased.Hightemperature days mainly occurred from sowing to jointing,and the frequency of light water deficit and medium water deficit increased by 6％ and 7％,respectively.The water surplus happened through the maize growing season,but it was always mild.The frequency of light water surplus increased by 15％ after climate warming,with 21％ and 11％ of stations increasing significantly during sowing-jointing and grain filling-maturity,respectively.The decrease in heat stress and cold stress has a good impact on the growth of spring maize,however,the increase in cloudy days and water surplus/deficit may decrease quality and yield.
