Changes of storm surges in the Bohai Sea derived from a numerical model simulation, 1961–2006

Abstract

Using the tide-surge circulation model ADCIRC, the storm surges in the Bohai Sea were hindcasted from 1961 to 2006 after a regional model-based reconstruction of wind conditions. Through comparison with four storm surge cases that happened in the Bohai Sea and long-time observations at four tide gauges in the Yellow Sea, it is concluded that the model is capable of reproducing the conditions of storm surges in the past few decades in this area. The spatial distribution, the seasonal variation, the interdecadal variability, and the long-time trend were analyzed using the model results. Results show that the storm surges in the three bays of the Bohai Sea are more serious than those in other areas. The storm surges exhibit obvious seasonal variations—they are more serious in spring and autumn. Obvious interdecadal variations and long-time decreasing trends take place in the Bohai Sea. Storm surge indices show statistically significant negative correlations to the Arctic Oscillation (AO) and a statistically significant positive correlation to the Siberian High (SH). Linear regression analysis was used to determine a robust link between the indices of the storm surges and the AO and SH. Using this link, conditions of the storm surges from 1900 to 2006 were estimated from the long-time AO and SH.

Appendix

1.1 The calculation of the intensity of the Siberian High

Following the work by Gong and Wang (1999), an index I to represent the intensity of Siberian High is used here:

$$ I=\frac{{\displaystyle \sum_{n=1}^N{P}_n{\delta}_n \cos {\varPsi}_n}}{{\displaystyle \sum_{n=1}^N{\delta}_n \cos {\varPsi}_n}} $$

where P _n is the sea level pressure at point n, and Ψ _n refers to the latitude of point n. When P _n  ≥ 1028 hPa, δ _n  = 1, and when P _n  ≤ 1028 hPa, δ _n  = 0. The selected area is bounded by 30° N, 60° E in the southwest and by 70° N, 120° E in the southeast.