Temporal and spatial variations in ozone over Asian free troposphere

Tropospheric ozone plays an important role in Earth's atmospheric environment and radiative balance. To assess the temporal variation of tropospheric ozone over Asia, ozone data from the Trajectory-mapped Ozonesonde dataset for the Stratosphere and Troposphere (TOST) were collected, evaluated, processed, and analyzed. Comparing TOST with ozonesonde station data and satellite data, there are good agreements with a high correlation (r at maximum = 0.88), low bias (<10 ppbv), and low root-mean-squared error (<20 ppbv). The time series analysis shows increasing trends of the tropospheric ozone mixing ratio for both TOST and satellite data, with the Sen-Theil slopes of 0.4417 and 0.7158 ppbv/year, respectively.