Ocean Response to Successive Typhoons Sarika and Haima (2016) Based on Data Acquired via Multiple Satellites and Moored Array

Abstract

Tropical cyclones (TCs) are natural disasters for coastal regions. TCs with maximum wind speeds higher than 32.7 m/s in the north-western Pacific are referred to as typhoons. Typhoons Sarika and Haima successively passed our moored observation array in the northern South China Sea in 2016. Based on the satellite data, the winds (clouds and rainfall) biased to the right (left) sides of the typhoon tracks. Sarika and Haima cooled the sea surface ~4 and ~2 °C and increased the salinity ~1.2 and ~0.6 psu, respectively. The maximum sea surface cooling occurred nearly one day after the two typhoons. Station 2 (S2) was on left side of Sarika’s track and right side of Haima’s track, which is studied because its data was complete. Strong near-inertial currents from the ocean surface toward the bottom were generated at S2, with a maximum mixed-layer speed of ~80 cm/s. The current spectrum also shows weak signal at twice the inertial frequency (2f). Sarika deepened the mixed layer, cooled the sea surface, but warmed the subsurface by ~1 °C. Haima subsequently pushed the subsurface warming anomaly into deeper ocean, causing a temperature increase of ~1.8 °C therein. Sarika and Haima successively increased the heat content anomaly upper than 160 m at S2 to ~50 and ~100 m°C, respectively. Model simulation of the two typhoons shows that mixing and horizontal advection caused surface ocean cooling, mixing and downwelling caused subsurface warming, while downwelling warmed the deeper ocean. It indicates that Sarika and Haima sequentially modulated warm water into deeper ocean and influenced internal ocean heat budget. Upper ocean salinity response was similar to temperature, except that rainfall refreshed sea surface and caused a successive salinity decrease of ~0.03 and ~0.1 psu during the two typhoons, changing the positive subsurface salinity anomaly to negative

Changes in the hydrodynamic characteristics of the upper layer of the South China Sea during the period of super typhoon Rammasun (2014)

“…The major anomalous oceanic characteristic during super typhoon Rammasun was SST cooling after the typhoon's passage. Assessments of the daily variabilities of SST, MLD, SLA, SSW and precipitation and the relationships between them during the period of the typhoon yielded the following results: After typhoon Rammasun had passed through the SCS in July 2014, the maximal SST cooling exhibited a clear 'right-hand-side intensification' (Stramma et al, 1986;Wada, 2005;Wu et al, 2019) while heavy precipitation showed an obvious 'left-hand-side intensification' (Chen et al, 2006;Zhang et al, 2019) with respect to the typhoon track. The SST response exhibited obvious rightward biases because of the rotation resonance of the wind vector with wind-driven inertial currents (Yue et al, 2018), and precipitation response showed significant leftward biases due to vertical wind shear (Chen et al, 2006;Lin and Oey, 2016).…”

Effects of Model Coupling on Typhoon Kalmaegi (2014) Simulation in the South China Sea

“…Additionally, Buoys 1 and 4 show a slight SST recovery after the passage of Typhoon Kalmaegi, while at Buoys 2 and 5, the SST continues to decrease steadily. According to the literature, SST recovers within a few days to weeks [26,80,81]. It is worth noting that there is a difference in SST at the beginning of the run, which results from the initial conditions applied to ROMS.…”

“…The latest studies have documented the role of ocean surface waves in air-sea interactions during TC events in different parts of the world [7,[23][24][25][26][27]. Wave generation and growth are a direct effect of the surface wind.…”

Response of Coastal Water in the Taiwan Strait to Typhoon Nesat of 2017

“…Furthermore, our previous works (e.g., [2,50,[88][89][90][91][92][93]) indicate thatoceanic thermohaline and dynamic features play an important role in upper ocean response to a single or sequential typhoons based on multiple observation data and model simulations. However, these works were mainly in the marginal sea (the South China Sea) and we may further follow the study of this paper, and study how some special topographic features such as with many islands or straits influences the structure of the oceanic response to typhoons in the future.…”