The impact of channel effect on Asian dust transport dynamics: a case in southeastern Asia
Abstract. A super heavy dust event was identified with unprecedented PM10 in terms of speed and concentration in the southeastern Asia. The average concentration was observed exceeding the value of 1000 μg m−3 for the duration lasting more than 10 h, with the highest value reached 1724 μg m−3 in northern Taiwan on 21 March 2010. We found that this case exhibited an uneven and intriguing spatial distribution of PM10 concentration and transport speed between eastern and western Taiwan. Higher values were observed in the western and northern areas. The peak concentrations can vary up to 5-fold between western and eastern Taiwan, and ten-fold between the northern tip and southern tip of Taiwan, only about 400 km apart. A high resolution, 10 km, numerical study by Weather Research Forecast (WRF) and WRF-chem models revealed that this intriguing spatial distribution of the Asian dust transport was resulting from a strong coupling effect of the geographic channel effect and blocking of the easterly from the Pacific Ocean. We are confident that this coupling effect can be revealed only by applying a high resolution numerical study in other similar regions.
