The timefrequency characteristics of four intensity indices Ii(i=1,4〖TX-〗)and two center position indices (〖WTBX〗λ〖WTB1〗i,〖WTBX〗φ〖WTB1〗i;i=3,4〖TX-〗)of the Aleutian low(AL) proposed by different scholars since the 1990s are analyzed and compared in this paper,and their correlation relationships with the sea surface temperature(SST) of the Pacific Ocean,air temperature and precipitation in the Northern Hemisphere during the same period are investigated.The results show that evolutionary features of Ii(i=2,4〖TX-〗) are mostly similar:the AL was weaker before the mid1970s,then stronger,and becomes weaker again in recent years;larger differences existed between I1 and Ii(i=2,4〖TX-〗) probably because I1 is defined according to the 5month mean pressure field.The geographic distributive range of the appearance of the center position of the AL determined by (〖WTBX〗λ〖WTB1〗c3,〖WTBX〗φ〖WTB1〗c3) is larger than that by (〖WTBX〗λ〖WTB1〗c4,〖WTBX〗φ〖WTB1〗c4),which might be caused by the differences in the length of average time period and the different definitions of the center position between them;and it is about 5yr earlier for 〖WTBX〗λ〖WTB1〗c4 to turn from the negative position anomaly phase to the positive one than the time when 〖WTBX〗λ〖WTB1〗c3 did,and the tuning time of 〖WTBX〗λ〖WTB1〗c4 is also more consistent with the transition time of intensity indices Ii(i=2,4〖TX-〗).In strong EI Ni〖AKn~D〗o events,the AL strengthened with its center shifting eastward;and vice versa in La Ni〖AKn~D〗a events.In this respect,intensity indices I2 and I4 and position indices〖WTBX〗 λ〖WTB1〗c4 and 〖WTBX〗λ〖WTB1〗c3 are comparatively better.When the AL was stronger (〖WTBX〗〖AKI~〗′〖WTB1〗i<0) and lay eastward of its normal position (〖WTBX〗〖AKλ~〗〖WTB1〗′ci>0),it was colder and drier in the midlatitude North Pacific region and the southern area of North America,but warmer and wetter in the northeast area of North Pacific,and vice versa.