北太平洋海温异常对四川省春季林火的影响

Influence of Sea Surface Temperature Anomalies of North Pacific on Spring Forest Fire in Sichuan Province

为保护和发展四川省生态环境和森林资源,完善四川省森林火险预报预警业务,笔者利用四川省1979—2012年森林火灾观测数据、NCEP/NCAR再分析环流资料以及美国NOAA全球海表温度资料,分析了四川省森林火灾的时空分布特征,并对前期海温影响林火的可能机制进行了探讨。结果显示:四川省林火重灾区(凉山州、攀枝花市和甘孜州)春季林火次数与冬季北赤道暖流区(5°—25°N,165°E—140°W)海温呈显著负相关关系,而与北太平洋暖流区(25°—45°N,165°E—140°W)海温呈显著正相关关系。因此,建立了用于诊断和预测重灾区春季林火异常发生的判别指数FI。通过分析FI与北半球500 h Pa高度场的关系,认为北太平洋海温异常通过持续性地影响欧亚中高纬地区环流异常,进而影响到重灾区春季林火的发生。

The paper aims to protect the ecological environment and forest resources, perfect the forest fireforecasting and warning operation in Sichuan Province. The temporal and spatial characteristics of forest fire inSichuan and their relationship with the SST anomalies of North Pacific were analyzed, using the original data offorest fire from 1979- 2012, the NCEP/NCAR reanalysis data, and the sea surface temperature data fromNOAA. The result showed that a close negative/positive correlation existed between the forest fire in the majordisaster area（Liangshan Prefecture, Panzhihua City and Ganzi） and the early winter SST in the neighborhood ofthe North Equatorial Current Region（5°-25°, 165°E-140°W）/the North Pacific drift（25°-45°N, 165°E-140°W）, respectively. A discriminate index for diagnosing and forecasting the spring forest fire was definedaccording to the correlation distribution characteristics. By analyzing the relationship between FI and 500 h Paheight field in the northern hemisphere, the authors believed that the North Pacific SST abnormalities werelikely to affect spring forest fire in major disaster area through the persistent influence on Eurasian highlatitude circulation anomalies.