Distribution and trends of the cold-point tropopause over China from 1979 to 2014 based on radiosonde dataset

•The significant cooling rate of -0.70K/decade for the temperature of tropopause is reported over China during 1979-2014•The height of tropopause over China is rising with the rate of 273 m/decade during 1979-2014.•The latitudinal distribution and variations of height and temperature of tropopause are reported over China•The nonuniform latitudinal and longitudinal distribution of trends of height (temperature) of tropopause are first presented•Reconfirm the expansion of the tropics: the difference of tropopause temperature among latitudes is enlarging year by year

The variation trends of the cold-point tropopause (CPT) are presented using radiosonde observations from 77 stations over China during 1979-2014. The latitude regions over China from 18°N to 53°N are divided into 7 latitude zones with every 5° intervals, and the spatial areas of 18°N-53°N, 75°E-135°E are divided into 27 lattices with 5° × 10° grids. The annual-mean values of height-of-CPT (H-CPT) and temperature-of-CPT (T-CPT) are then calculated by all the available samples within each latitude and longitude bin. By using the least squares regression method, it is found that the H-CPT increases with the rate of 273 m/decade, and overall the significant cooling rate of − 0.70 K/decade for the T-CPT over the whole of China. Then, the trends and latitude distribution of H-CPT and T-CPT for each latitude zone are analyzed. The difference of H-CPT among latitude distribution characteristic is reducing year by year, and the difference of T-CPT is enlarging. The H-CPT displays a rising trend between 28°N-53°N latitude region with the positive change rates, and it has decline trend between 18°N-28°N latitude region with the negative change rates. The change rates of T-CPT are negative values for all latitude zones. At last, the nonuniform latitudinal and longitudinal distribution of long-term trends of H-CPT and T-CPT are first presented for each spatial cell.