Differences in the Rainfall Characteristics between Mount Tai and Its Surrounding Areas

As a typical small-scale, isolated topography, Mount Tai exhibits great differences in precipitation characteristics from the surrounding areas. It was found that the amount of rainfall occurring over Mount Tai is significantly larger than what is observed in the surrounding areas. Based on hourly rain gauge records for the warm season(May to September) of 1996–2015, differences between Mount Tai and its surrounding areas were further revealed in terms of rainfall diurnal variation, spatial scale, and evolution process. The diurnal variation of the enhancement on rainfall amount exhibit "dual peaks" occurring in the early morning and afternoon, and the dual peaks are mainly attributable to rainfall frequency. The diurnal phase of the rainfall amount in the surrounding areas lags 1 h behind that over Mount Tai. Regarding differences in rainfall spatial scale, compared to those of surrounding areas, precipitation over Mount Tai is characterized by a smaller coverage, especially in the early morning. Mount Tai also tends to have a kind of unique, small-scale rainfall in the afternoon and at night. Based on statistical analysis of precipitation events,differences in rainfall evolution process were identified as well. Rainfall over Mount Tai often starts earlier in the afternoon and ends later at night than it does in the surrounding areas. Furthermore, nocturnal rainfall events over Mount Tai are prone to peaking over a shorter period and enduring for a longer period after reaching their maximum intensity, compared with nocturnal rainfall events occurring in the surrounding areas. Rainfall events over Mount Tai always last longer, especially those occurring in the early morning. In general, Mount Tai has a large enhancement effect on rainfall.