Abstract:Using conventional upper-air and surface observations, Doppler radar data, satellite nephogram and ERA5 reanalysis data, this paper analyzes drylines cases and drylines triggering convections in Shandong Province from 2001 to 2022. The results are as follows. The total number of days with drylines in Shandong from 2001 to 2022 is 451 d, of which there are 156 d with convective drylines， respectively. Convective drylines occur mainly from April to September. May and the first dekad of May are the month and dekad periods to have the highest occurrence frequency of drylines, respectively. Drylines mainly occur between 14:00 BT and 17:00 BT in the afternoon, distributed often in central and northwestern Shandong. The formation of drylines is related to the influence of mountain ranges and the distribution of land and sea. The widths of convective and non-convective drylines are 75-106 km and 80-114 km respectively, with dew point temperature gradients being 11.8-16.7 ℃·（100 km）-1 and 9.8-15.0 ℃·（100 km）-1 respectively. Temperatures on both dry and wet sides of drylines vary from 23℃ to 33℃, with a temperature gradient of 1-3 ℃·（100 km）-1, and temperature on the dry side is slightly higher. Compared to non-convective drylines, convective drylines exhibit higher temperatures and dew point temperatures on both the warm and cold sides, narrower widths, and greater dew point temperature gradients. This is because the circulation associated with the force-driven component becomes stronger when the horizontal dew point temperature gradient is large. The thresholds of the key environmental parameters for drylines triggering convections reveal that the convective parameters such as energy and stratification stability all exhibit a certain degree of distinguish ability. The vertical wind shear in the deep layer (0-6 km) is also distinguishable, whereas vertical wind shear in the lower layers (0-1 km and 0-3 km) is difficult to distinguish due to the small differences. The seasonal variation in convective parameters under unstable conditions is relatively small, but environmental parameters related to moisture conditions and 0-6 km vertical wind shear exhibit significant seasonal differences, so their thresholds should be differentiated by season. Drylines frequently develop under conditions of northwest airflow, ahead of westerly trough, and northeast low-pressure vortex at 500 hPa. At the lower 700 hPa and 850 hPa, drylines are primarily influenced by the shear line of the low-pressure vortex or the northwest airflow, with the boundary layer often accompanied by convergence lines. The surface primarily lies within the convergence flow field of continental warm low pressure or at the bottom or front of low-pressure systems.