Abstract
Dust particles are effective ice nuclei and are known to affect
precipitation. Here, the possible impacts of mineral dusts on summertime
cloud and precipitation over the Taiwan region are investigated through
analysis of 25 years (1989 – 2013) of multiple observational and
modeling datasets. Due to the unique mechanism, typhoon precipitations
are excluded in this study. Statistical methods are used to untangle the
influences of dust from the co-varying water vapor conditions. The
results suggest a statistically significant positive correlation between
non-typhoon precipitation and number concentration of dust particles
larger than 0.5 µm () in July and August in the regions with heavy
precipitation. From clean (0.008 cm) to dusty days (0.2 cm), averaged
ice (liquid) water paths and precipitation increase by
~25% (~20%) and ~70%
over the orographic region, and vertically, ~30% more
cloud ice content is generated at ~ 350 hPa (T =
~−20℃), enhancing the development of the mixed-phase
cloud and precipitation. The results also indicate critical role of the
atmospheric water vapor in the responses of precipitation to , with
precipitation increasing more significantly with in higher water vapor
circumstances.