广东近40年土壤水蒸散发时空变化特征

Spatial and Temporal Variation of Evapotranspiration of Soil Water across Guangdong Province during Past 40 Years

用Peman公式计算了华南广东12个气象站1971~2010年潜在蒸散值,并分析了其时空变化特征。潜在蒸散值随纬度的升高减少,变化范围为680~1800 mm a-1;潜在蒸散的大小主要受温度和降水支配,20世纪80年代最小,90年代以后,随气候变暖,潜在蒸散值增加明显,本世纪00年代达到最高值,突变年为2004年。中亚热带夏季最高,南亚热带及北热带春季最高,各地冬季均最小。一年当中,地表湿润指数最高的时段为5月及6月,最低时段为冬季及秋季11月,最高的季节为春季,其次为夏季和秋季,最低为冬季。湿润度指数随纬度的降低下降明显,春季和冬季最为突出,湿润程度最好的时期为20世纪80年代,最差为21世纪的00年代,以春季下降最多。广东各地不同季节出现不同程度的土壤水分亏缺,作物生长所需水分未及最适宜状态,造成不同程度的季节性干旱,主要为各地的秋旱、南部地区的春旱和中南部的冬旱,南部地区春旱重于秋旱,北部地区秋旱重于春旱。针对不同地域不同旱灾,采取有效防旱抗旱措施成为保障当地农业产业持续发展的有效途径之一。

Potential evapotranspiration values of 12 weather stations in 1971 ~ 2010 in Guangdong province were calculated and compared by Peman-Monteith formula. The characters of spatial and temporal variation were analyzed.The results showed that the potential evapotranspiration values declined with the increasing latitudes and ranged680-1800 mm a-1, which being mainly controlled by temperature and precipitation. The potential evapotranspiration values increased with climate warming. The minimum was in 1980 s, and the maximum was in 2000 s, and the mutation point appeared in 2004. The highest potential evapotranspiration values separately existed in the summer Middle subtropical zone and spring South subtropical zone and North tropic zone, while the lowest ones always occurred in winter. Surface wetness index was highest in May and June and lowest in November; it values seasonally decreased as spring > summer > autumn > winter. The moist index declined significantly with the decrease of latitude, especially in spring and winter. The wetness degree was highest in the 1980 s, and lowest in the 2000 s, and decreased greatest in spring. Soil moisture content wasn't maintained in a suitable condition during crop growth. And soil water deficit led to droughts at different levels in different seasons, including the autumn drought in all areas, spring drought in the south areas and winter drought in the middle and south areas. The spring drought was more serious in the south than in the north of Guangdong province, while the autumn drought was more serious in the north than in the south of Guangdong province. One of the most effective ways for sustainable development of local agricultural industry is to take effective and specific measure for the individual drought area.