Abstract: Based on the meteorological observation data from 11 weather stations from 1873 to 2009 in Shanghai, the arctic oscillation indices from 1951 to 2009 and the Siberian high intensity data from 1873 to 2000, the temporal changes of diurnal temperature range (DTR), the abnormal changes of atmospheric circulation, the changes of other meteorological elements and the effects of urbanization development on DTR were analyzed. The results indicate that the DTR decreases significantly in the past 137 years in Shanghai, and the rate is 0.15 ℃ per 10 years. The seasonal diurnal temperature ranges are also in decreasing trends. The maximum and minimum decreasing rates of diurnal temperature ranges occur in autumn and winter, respectively. The arctic oscillation indices change from the negative phase to the positive phase in recent 60 years, while the Siberian high intensity is from the positive anomaly to the negative anomaly in recent 130 years. As a result, the increasing amplitude of the minimum temperature is higher than that of the maximum temperature, which leads to decrease of DTR. The DTR is in a positive correlation with sunshine duration and in a negative correlation with precipitation in four seasons and the whole year. The effect of urbanization on the decrease of DTR is significant.

Key words: Diurnal temperature range (DTR), Maximum air temperature, Minimum air temperature, Arctic Oscillation, The Siberian high, Shanghai in China