近33 a西北太平洋极端海表温度事件的变化特征及与ENSO的关系

使用1982~2014年美国国家海洋和大气管理局（national oceanic and atmospheric administration，NOAA）最优插值1/4度逐日海温分析资料，分析西北太平洋极端海表温度（sea surface temperature，SST）事件的变化特征，探讨极端SST事件与ENSO（El Ni?o-southern oscillation，ENSO）之间的关系。结果表明:极端高温事件的频率明显增大，20世纪80年代为2~5 a一遇，20世纪90年代为1~4 a一遇，21世纪以来，除2004和2011年外，其余年份均有发生。极端高温发生天数呈线性增加趋势，增长速率为30 d/10 a。单次极端高温事件持续时间逐渐增长，增长速率为0.56 d/次，且平均温度和最高温度也呈上升趋势，上升速率分别为0.032℃/次和0.049℃/次。相反的是，极端低温事件的频率明显减小，1982~2000年为1~2 a一遇，21世纪以来，发生次数明显减少。极端低温发生天数和单次事件的持续时间均明显减少，减少速率分别为-27 d/10 a和-1.6 d/次。单次极端低温事件的平均温度和最低温度呈线性上升趋势，增长速率分别为0.0087℃/次和0.017℃/次。极端高温事件呈现1~4 a和4~7 a周期的高低频震荡，低温事件呈现多尺度周期变化，主周期尺度为3~4 a。Nino 3.4区下半年ENSO指数与西北太平洋极端高温呈显著负相关，与极端低温事件呈显著正相关。意味着在La Ni?a年份，极端高温事件更容易发生。反之，在El Ni?o年份，极端低温事件容易发生。

Variation characteristics of the extreme sea surface temperature events in the Northwest Pacific and its relationship with ENSO over the past 33 Years

Utilizing The NOAA Optimum Interpolation 1/4 Degree Daily Sea Surface Temperature Analysis data for the period 1982~2014.Variation characteristics of the extreme SST events and its relationship with ENSO in the Northwest Pacific are analyzed.The results indicate that:The frequency of extreme high temperature eventshas increased significantly, In the 1980s it was 2 to 5 years, and in the 1990s it was 1 to 4 years, since the 21st century, except for 2004 and 2011, other years have occurred.The number of days with extreme high temperature increased linearly with an increase rate of 30 d/10 a.The duration of a single extreme high temperature event gradually increased with an increase rate of 0.56 d/time, and the average temperature and maximum temperature also showed an upward trend, with the rate of increase being 0.032℃/time and 0.049℃/time, respectively.On the contrary, the frequency of extreme cold events has decreased significantly, from 1982 to 2000 once in 1~2 years, and since the 21st century, the frequency of occurrence has decreased significantly.The duration of the days of extreme cold temperature occurrence and the duration of single event both decreased significantly, with the reduction rate of -27 d/10 a and -1.6 d/time respectively.The average temperature and the minimum temperature of a single extreme cold temperature event showed a linear upward trend with a growth rate of 0.0087℃/time and 0.017℃/time.The extreme high temperature events show high and low frequency oscillations in the 1~4 year and 4~7 year cycles.The cold events show a multi-scale periodic variation with a main period scale of 3~4 years.In the second half of Nino 3.4, the ENSO index was significantly negatively correlated with the extreme high temperature in the western North Pacific, and was significantly positively correlated with extreme cold events.This means that in the La Ni?a years extreme heat events are more likely to occur.On the contrary, in the El Ni?o years, extreme cold events are prone to occur.