Sea Surface Temperature and Ocean Heat Content during Tropical Cyclones Pam (2015) and Winston (2016) in the Southwest Pacific Region

Abstract

The sea surface temperature (SST) and upper ocean heat content (OHC) have been explored along the track of two tropical cyclones (TCs), TC Pam (2015) and TC Winston (2016). These TCs severely affected the islands of Vanuatu and Fiji, in the South Pacific Region (8°–30°S, 140°E– 170°W). The SST decreased by as much as 5.4°C along the tracks of the TCs with most cooling occurring to the left of the TCs tracks relative to TCs motion. SST cooling of 1-5°C has generally been observed during both the forced and relaxation stages of TC passage. The Argo profiles near the TC revealed observable mixed layer deepening. Subsurface warming was also observed post-TC passage from the temperature profile of one of the floats after the passage of both TCs. The OHC and heat fluxes are seen to play an important part in TC intensification as both these TCs intensified after passing over the regions of high OHC and enhanced heat fluxes. Apart from the traditionally used OHC obtained up to the depth of the 26°C isotherm (QH), the OHC was also determined up to the depth of the 20°C isotherm (QH,20). The QH and QH,20 values decreased in the majority of cases post TC passage while QH,20 increased in one instance post-TC passage for both the TCs. QH,20 has also been used to identify heat energy changes at deeper levels and correlated well with the traditionally used OHC during the weaker stages of the TCs.

Observational evidence of overlooked downwelling induced by tropical cyclones in the open ocean

“…Following Chandra and Kumar 74 , the UOHC can be expressed as follows: where is seawater density, (= 4178 J kg °C −1 ) is specific heat capacity, and is temperature. is defined similarly to , with the exception of that represents a mean value since the timeseries of is not provided in this study.…”

Impact of Satellite Wind on Improving Simulation of the Upper Ocean Response to Tropical Cyclones

“…In this study, the Argo temperature profiles were used to validate the sea surface temperature characteristics simulated by the numerical model. The selected Argo profiles should ensure that the distance between the location of the TC center and the position of the Argo buoy is within 200 km [49,50], as this region is typically the most affected by the TC winds.…”

Three‐Dimensional Temperature Responses to Northward‐Moving Typhoons in the Shallow Stratified Yellow Sea in Summer

“…They can cause intense vertical mixing and anomalous three‐dimensional circulations in the ocean, both of which result in dramatic variations in water temperature (Liu et al., 2022). In the open ocean, the intense vertical mixing generated by typhoons' strong winds leads to significant sea surface cooling and subsurface warming, which are usually biased to the right/left side of the typhoon tracks in the Northern/Southern Hemisphere (Chandra & Kumar, 2021; Price, 1981; Wang et al., 2016; Wu, Zhang, & Chen, 2020; Zhang et al., 2016). The rightward/leftward bias in significant temperature responses in the surface and subsurface layers is attributed to both the stronger wind stress and resonance between the anticlockwise/clockwise rotating winds and inertial currents on the right/left side in the Northern/Southern Hemisphere (Price et al., 1994; Sanford et al., 2007; Shay et al., 1989).…”