Landfalling tropical cyclones activities in the south China: Intensifying or weakening?

摘要

Long-term tropical cyclone (TC) data are analysed to investigate variations of the landfalling TCs in the southern China by taking Guangdong province as a case study. Changing characteristics of the sea surface temperature (SST) for the entire Pacific and the Ni?o3.4 index are also analysed with aim to show possible impacts of SST on the behaviours of TCs making landfall at the Guangdong province (TMLGP). On the basis of a change-point analysis for the frequency of TMLGP, the time period 1965-2007 is subdivided into 1965-1996 and 1997-2007. The results indicate that (1) the frequency of TMLGP is influenced on inter-annual time scales by SST variations in the South China Sea and the western North Pacific (WNP) for the period 1965-1996. The frequency of TMLGP after 1996 has a nearly opposite trend compared to the period preceding 1996. Therefore, the frequency of TMLGP for the period 1965-2007 as a whole is in an insignificant relation with SST in these two periods; (2) The frequency of TC landfall could be attributed to the WNP TC activities which are represented by a relatively good agreement of the frequency of TMLGP with the total number of TCs; (3) Generally, El Ni?o/La Ni?a-southern oscillation (ENSO, here depicted by Ni?o3.4 index) exerts a considerable impact on the frequency of TMLGP; (4) The various SST measures only have a weak influence on TMLGP intensities. Despite the long-term warming trend in SST in the WNP, no long-term trend is observed in either the frequency or intensities of TMLGP.