Final_Distribution and Trends of the Cold-Point Tropopause over China from 1979 to 2014 Based on Radiosonde Dataset.doc

he Trends of the Cold-Point Tropopause CPT are presented using high-resolution radiosonde observations from 77 stations over China during 1979—2014. The latitude region from 18°N to 53°N is divided into 7 latitude zones with every 5° intervals and the spatial area of 18°N—53°N 75°E—135°E is 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 obtained. First by using the least squares regression method it is found that the H-CPT increases with rate of 273m/decade and overall significant cooling rate of -0.70K/decade for the T-CPT over China. Then the trends and latitude distribution of H-CPT and T-CPT for each latitude zone are reached. The change rates even the change direction of H-CPT H-CPT show obviously latitude distribution characteristics. The characteristic difference of H-CPT among latitude distribution is reducing year by year and corresponding T-CTP is enlarging. The H-CPT displays uplift trend between 28°N—53°N latitude region with the positive change rates and corresponding 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. Third the spatial latitude-longitude distribution of long-term trends of H-CPT T-CPT for each grid are obtained. The change rates of H-CPT T-CPT are not only dependent on latitude but also on longitude. At last the spatial structure of annual fluctuation of H-CPT T-CPT for each grid are obtained. The fluctuation of standard deviations of T-CPT is not only related to spatial distribution but also to economic belt of China.