1566 / 2019-08-21 16:12:00

Changes in Interday Temperature Fluctuation over the Chinese Loess Plateau

9、大气科学与全球变化 > 专题6：区域气候变化动力学

In order to study the regularity of short-term temperature fluctuation in the context of global warming, daily temperature data collected at the 53 meteorological stations in the CLP are used to count the number of days in which average interday temperature fluctuation (ITF) is greater than 1 °C (ITFD) and calculate the standard deviation of ITF (ITFA). The temporal variation and spatial distribution of short-term temperature fluctuation frequency and amplitude in the CLP, and its the large scale circulation background are analyzed. The results are as follows: (1) In terms of numerical characteristics, the frequency of ITF in three temperature variables (Tmean, Tmax and Tmin) increase is higher than that of ITF decrease in one year. Among them, the first half of the year was mainly warming, but the second half was cooling. On the monthly scale, the ITF rises most in March, decreases most in November, and the ITFs in January and July are relatively small. (2) Overall, Tmax's ITFD and ITFDI have contributed a lot to the growth trend of Tmean's ITFD and ITFDI, yet ITminFDD has a great influence on the decreasing trend of ITmeanFDD. On another note, ITFDI has a greater impact on the trend of ITFD, while ITFDD has a smaller impact. Three ITFD indices have obvious phased characteristics of inconsistent length in monthly series, and the three ITFD indicators of Tmax is larger than Two other temperature variables. The ITFDI in the first half of the year is warming, and the change of ITF in the second half of the year is mainly cooling. Spatially, ITFD and ITFA have higher positive correlation coefficients with latitude and longitude (p<0.05). The frequency and amplitude of ITF in spring are relatively large. (3) There are obvious spatial differences in the time series trend of ITFD indices across the CLP from 1961 to 2015, while stations with negative trend in ITFD indicators are mostly concentrated in the southeast of the CLP and stations with negative trend in ITFA indicators mainly focus in the northwest of the CLP. (4) The CLP was affected by circulation from multiple directions in the 850 hPa geopotential height during the period of 1961-2015. At 850 hPa geopotential height, stronger ITF of the CLP is affected by Mongolian high and Aleutian low, while at 500 hPa geopotential height, stronger ITF of the CLP is mainly affected by Mongolian high. Due to the process of biological growth and development, and people’s daily life are closely related to temperature, results of the present paper suggest that short-term temperature fluctuation may also need to be considered when discussing long-term impacts of climate change on ecosystems.