Modulation of observed sea surface temperature variation by the quasi‐biweekly oscillation in the tropical western Pacific during boreal summer

Abstract

Using 17‐year in situ buoy observations, this study investigates how sea surface temperature (SST) over the tropical western Pacific Ocean is modulated by the quasi‐biweekly oscillation (QBWO) during boreal summer. The 10‐buoy mean phase‐by‐phase composites of SST indicate that SST evolution lags behind the convection cycle by approximately one quarter, with the maximum SST occurring in Phase −90° (29.68°C) and the minimum SST occurring in Phase 90° (29.37°C). The diurnal cycle of SST (dSST) is in phase with the convection cycle, with the minimum dSST occurring during the convectively active phase (0.34°C) and the maximum dSST occurring during the convectively suppressed phase (0.61°C). The fluctuation in the dSST reaches 0.27°C, which is similar to that in the SST (0.31°C). This kind of oscillation can be well explained by the evolution of the sea surface forcing parameters, especially the shortwave radiation and wind speeds, observed from the buoys. In addition, the composite range of the dSST suggests an interesting asymmetry between Phase −90° and 90°. The interaction of the background summer mean state and the 10–30‐day intraseasonal anomalies causes the asymmetry in wind speed between Phase −90° and 90°, which in turn results in the asymmetry in the dSST between these two phases. Since QBWOs are more likely to occur during El Niño developing summers than during El Niño decaying summers, the 10–30‐day intraseasonal SST and dSST variances during El Niño developing summers are stronger than those during El Niño decaying summers.

Sea Surface Energy Fluxes' Response to the Quasi‐Biweekly Oscillation: A Case Study in the South China Sea

“…The response in the sea surface turbulent heat fluxes to QBWO from Yang et al. (2021) is comparable to this study. Zhu et al.…”

“…The response in the sea surface turbulent heat fluxes to QBWO from Yang et al (2021) is comparable to this study. Zhu et al (2020) revealed a weaker R sd anomaly (60 W m −2 ) and a stronger Q l anomaly (−45 W m −2 ).…”

“…Yang et al. (2021) and Zhu et al. (2020) revealed that steady responses existed in sea surface energy fluxes during QBWO.…”

The Impact of Diurnal Variability of Sea Surface Temperature on Air–Sea Heat Flux Estimation over the Northwest Pacific Ocean

“…The SST DV is a complex phenomenon influenced by various factors, such as solar radiation, sea surface winds, clouds, precipitation, dynamic ocean processes, and biological processes [9,33,34]. In particular, solar radiation is the primary driver of SST DV, causing the upper ocean to absorb a significant amount of heat, resulting in a positive correlation with SST DV.…”