Sea salt particles transported to the land

Abstract

Large quantities of sea salt particles are suddenly transported to the land by the discrete events of a violent storm. In Japan these events are the typhoon in summer on the Pacific coast region and the north-west monsoon in winter on the Japan Sea coastal region. The share of “sedimentation”, one of the mechanisms of the transport of sea salt particles to the land, is only about 20% of “precipitation” over various parts of Japan. The contribution of “impaction” with surface obstacles is negligibly small, as observed in the example of the Ogōchi Basin. This conclusion was also confirmed by analysing the concentration of chloride in rivers undisturbed by other sources. Moreover, the analysis reveals the following facts. The half-decrease distance of the concentration is about 20 km from the coast in both coastal regions of Japan. The total deposition of sea salt was calculated to be 2.7 × 10¹² g/yr in the whole of Japan (area 3.7 × 10⁵ kmyb2) and the mean concentration of chloride in rain to be 2.4 ppm over Japan as a whole, but the concentration is about 3 times larger over the Japan Sea coastal region than over the Pacific coast region, owing to the violent north-west monsoon in winter.