Li, J.; Sun, L.; Yang, Y.; Yan, H., and Liu, S., 2020. Upper ocean responses to binary typhoons in the nearshore and offshore areas of northern South China Sea: A comparison study. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 115–125. Coconut Creek (Florida), ISSN 0749-0208.

Changes in sea surface temperature (SST) and sea surface salinity (SSS) in response to the binary typhoons Sarika and Haima (2016) in the offshore and nearshore areas along the Guangdong Province Coast (GPC) and Hainan Island Coast (HIC) in the northern South China Sea are comprehensively investigated using multi-satellite observations and ocean reanalysis data. The results show that the maximum SST cooling was 2.5°C (average 1.5°C) and 6°C (average 2.5°C) after the passage of typhoon Sarika in the HIC nearshore and offshore, respectively. In contrast, the average SST cooling was 1°C in the GPC offshore and very marginal in the GPC nearshore after the passage of typhoon Haima. For SSS, typhoon Sarika induced changes of 0.1 psu and 0.35 psu in the HIC nearshore and offshore, respectively, while typhoon Haima caused changes of -0.1 psu and 0.3 psu in the GPC nearshore and offshore, respectively. The responses of both SST and SSS are similar in the offshores of both the GPC and the HIC. However, they are quite different in the nearshores of the GPC and the HIC. It is found that the nearshore responses to typhoon are quite different depending on the coast conditions: river discharge and advection of coastal current. In the GPC nearshore, the river discharge due to typhoon can lead to larger SSS decrease than that in the HIC nearshore. Besides, the advection of coastal high SSS water from the GPC to the HIC along coast made SSS decrease in the GPC but increase in the HIC. As a result, the SST and SSS responses are easily to be influenced, while they could exist much longer in the offshores.