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

The South China Sea (SCS) owns the world's strongest quasi-biweekly oscillation (QBWO) in boreal summer, but the mechanism is still unclear. This case study summarizes two modes of QBWO over the summer SCS in 2019 by using empirical orthogonal function on the 10-20-day bandpass-filtered outgoing longwave radiation fields. The maximum positive irradiance anomalies for the two modes are 90 W m(-2). The upward solar and downward longwave radiation anomalies own about 4%-8% of the irradiance magnitude, and the surface upward longwave radiation shows a weak response. Sea surface turbulent heat fluxes' responses to QBWO display different spatial patterns compared to radiation fluxes. Their changes are mainly ascribed to the surface wind in Mode1 and the air-sea thermal contrast in Mode2. We also discuss the cause and impact of sea surface turbulent heat fluxes on QBWO.