论文部分内容阅读
This study employed a trend EOF (TEOF) method to analyze the long-term (1950-2007) changes of diurnal temperature range (DTR) in Taiwan.Three statistically significant modes stand out.The TEOF1 depicts a monotonic decreasing trend of DTR,which is island wide except at Pengchiayu,Chengkung,Kaohsiung,and mountainous Yushan.The Mann-Kendalls tau (τ) rank correlations reveal that the increasing rate of daytime maximum (Tmax) at these stations is larger than the nighttime minimum (Tmin),thereby an increasing trend of DTR.The island wide reduction of DTR is closely related to the suppressed/enhanced cloud amount (CLD) during the daytime (nighttime) hours.The decreasing trend of Tmax in the western plains is consistent with the tendency in southeast China.The TEOF2 (TEOF3)depicts the low-frequency variations of DTR in central (northern) Taiwan.In both modes,the positive (negative) phase of DTR is attributed to the coordination between the positive (negative) phase of Tmax and negative (positive) phase of Train.Interestingly,the amplitude of TPC2 time series has an amplifying tendency after 1980.The connections between the regional DTR changes and global temperature extremes,and large-scale features in East Asia-tropical Pacific are also investigated.The results show that (1) the TEOF1 is related to global warming signal and likely regional anthopogenic emission as well; (2)the TEOF2 (TEOF3) is connected with the interdecadal changes of SST in the eastern (central) tropical Pacific Ocean.