NIE Yuhua,TANG Chaolian,CHENG Zemei
The Chi-wan tide gauge station is the only oceanic tidal observation site on the west coast of Shenzhen
that belongs to the State Oceanic Administration. Due to its special geological location, the Chi-wan Station is of significant importance in many fields, including sea level rise, storm tide prediction, and so on, in our country. In the present study, the tidal data of Chi-wan station ever since it was established were analyzed using a P-III curve-fitting method. The maximum sea level recurrence intervals at this station during 1965-2014 were obtained. The maximum sea level was 2.31 m for a one-hundred-years return period and 2.18 m for a fifty-years return period. Using an interpolation method, the yearly maximum sea levels at Chi-wan Station (x) and North Point/Quarry Bay Station (y) in Hong Kong during 1965-2011 were analyzed. It was found that there existed a significant correlation between x and y. The maximum sea levels in the recent one hundred years at Chi-wan station can thus be hindcast to be 2.7 m in 1962 and 2.34 m in 1937. According to the RCP2.6 in IPCC-AR5, the maximum sea level recurrence interval at Chi-wan Station at the end of the 21 th century (during 2081-2100) was also projected. It is projected to be 2.55 m for a one-hundred-year return period if the global sea level rises by 0.24 m and 2.71 m if the global sea level rises by 0.4 m. Finally, the influence of land reclamation on the sea level rising rate in the Ling-Ding waters and the influence of the No.0814 typhoon Hagupit on the storm tide at Chi-wan were discussed. The near shore terrain of Xixiang, which is located at the north part of Chi-wan, is very low. When the sea level exceeds 1.40 m, sea water will flow backwards in this area. That is to say, sea level rise in the future will increase the frequency of seawater flowing-backward near Chi-wan Station. Also, by analyzing the tidal observation data when typhoon passed by, it was found that, when typhoon Hagupit passed the Pearl River Estuary, the maximum sea level at Chi-wan Station increased by 1.46 m. In the present study, the maximum sea level recurrence interval at Chi-wan station was revised. This can not only improve the accuracy of water level warning in this area, but also provide reference for the prediction and precaution of storm tide in this sea area.