根据广东晚稻产量及生育期资料,采用逐日气象干旱指数DI计算各个生育期干旱指数,建立了晚稻干旱灾害评估模型并分析其时空特征。结果表明: ① 1981-2010年广东省平均晚稻干旱年频率为14 a一遇,减产率为0.7%,以轻旱为主。干旱主要发生在晚稻抽穗-乳熟期。②晚稻干旱频率及减产率均呈北高南低分布,旱灾高发区集中在西北部,频率为4~7 a一遇,减产率为1%左右。③近30 a广东省晚稻干旱灾害总体减弱但不显著,其中东南部干旱灾害趋于增强,其它地区均趋于减弱。④气候变暖后,晚稻全生育期、抽穗-乳熟期的干旱致灾频率和减产率呈减小趋势。由此可见,广东省晚稻干旱灾害的关键时期是抽穗-乳熟期,重点关注区域是西北部地区。
英文摘要:
Using yield and growth period data of late rice, drought index of each growth period was calculated by daily meteorological drought indicator (DI), and drought disaster evaluation model was established and temporal-spatial characteristics of the drought disaster was analyzed in this paper. Main results are: ① Average drought frequency of late rice in Guangdong during recent 30 years (1981-2010) was 6.9%; mean yield reduction rate was 0.7%. Drought disaster mainly occurred at milk to mature stage of late rice, and light drought day's accounted for the main. ② Spatial distribution of late rice drought frequency and yield reduction rate was high in the north and low in the east of Guangdong. High incidence region of drought located in northwest of Guangdong, where the drought frequency was 15%~25%, and yield reduction rate was 1%. ③ Drought disaster of late rice in Guangdong tended to decrease without statistical significance during recent 30 years, which tended to increase in the southeast while decrease at the other regions. ④ Drought frequency and reduction rate of late rice tended to decrease under climate change. Therefore, the key period of the late rice drought disaster in Guangdong is heading to milk stage, and the attentions should be paid more on the northwest of Guangdong.