近50年西南地区玉米干旱变化规律研究

Study on the Variation of Drought for Maize in Southwestern China in the Recent 50 Years

收集西南地区63站的气象资料、玉米生育期等资料,以水分供需关系为基础,构建玉米干旱指数(HI指数),反演1961-2010年各站的逐旬干旱,研究西南地区玉米干旱频率和干旱强度的时空分布特征.结果表明,近50年西南地区各地均有干旱发生,云南中部、东部和四川盆地中部、西部干旱频率在20%以上;云南中部及东北部的干旱强度明显比其余各地大.玉米出苗至拔节期干旱频率最高,特别是云南省中部和东北部的干旱频率达到40%~50%;拔节至抽雄期,轻旱、中旱、重旱均发生较少;抽雄至灌浆期干旱频率最低,但贵州局部地区重旱频率达到7%~9%;灌浆至成熟期,大部地区干旱频率10%~20%,其中重庆西部、四川盆地中部、东北部和贵州东部、云南东南部重旱频率约4.5%.

Meteorological data and the data of growth periods of maize at 63 meteorological stations in Southwestern China were collected ,and drought index (Hi index) for maize was constructed based on the relationship between water demand and water supply .Retrieval of every ten‐day drought for maize at the a‐bove stations during 1961-2010 was made to study the temporal and spatial distribution of drought fre‐quency and drought strength in Southwestern China .The results showed that drought for maize occurred in various regions in Southwestern China ,and the drought frequency was over 20% in eastern and middle Yunnan and in middle and western Sichuan Basin .Drought strength in middle and northeastern Yunnan was significantly greater than that in other regions .Drought frequency was the highest from emergence to jointing of the maize crop ,being as high as 40% -50% in middle and northeastern Yunnan ,in particular . Light ,medium and heavy drought occurred but occasionally from jointing to heading .Frequency of drought was the lowest from heading to seed‐filling ;however ,frequency of heavy drought might be as high as 7% -9% in some regions in Guizhou Province .Frequency of drought ranged from 10% to 20% in most regions from seed‐filling to maturity ,frequency of heavy drought being about 4.5% in the western part of Chongqing ,the middle and northeastern parts of Sichuan Basin ,the eastern part of Guizhou prov‐ince ,and the southeastern part of Yunnan province .