2.1 Sampling site and typhoons
The precipitation samples were collected at the top of a
~12 m high building in the Third Institute of
Oceanography, Ministry of Natural Resources (118°05′20″ E, 24°26′10″ N).
The sampling site is located in Xiamen Island, which is in the north
side of Jiulong River estuary, next to the Taiwan Strait (Fig.1). The
climate of Xiamen is typically dominated by the subtropical monsoon. The
precipitation from May to September is mainly controlled by the East
Asian Summer Monsoon with hot and humid climate; from October to
February, it is controlled by the Winter Monsoon with warm and dry
climate. From March to April each year, there is a seasonal shift
between winter and summer monsoons, and continuing precipitation occurs
due to the convergence of cold and warm air, which is also known as the
plum rain season in China. The average annual temperature is 21 °C and
the average annual precipitation is approximately 1200 mm. More than
80% of the annual precipitation occurs during the rainy season from
March to September. Due to the temperature differential airflow in the
Pacific Ocean, the study area is affected by 2~3
typhoons on average every year, most of them between July and September.
The amount of precipitation during a typhoon usually accounts for
50%–80% of the monthly precipitation.
[Insert Figure 1]
The origin area and intensity of typhoons studied in this research are
listed in the Table 1 and the typhoon tracks are shown in Fig. 1. More
details about four typhoons are given in Supplementary Text S1.
[Insert Table 1]