低风速涌浪条件下浪致应力的研究

本文基于2012年2月15日至5月8日的广东省茂名市附近海上铁塔实测数据,分析了海气边界层的湍流运动。结果证实,在涌浪条件下,协谱和Ogive曲线存在明显受涌浪影响的区域。本文进一步研究,发现浪致雷诺应力的正负符号变化与波龄相关,并给出了顺风向和侧风向浪致雷诺应力正负符号反转时波龄的统计分布。此外,本文基于协谱法提取了浪致雷诺应力τ_(swell),并与传统方法得到的浪致雷诺应力τ_(*swell)做比较。结果表明,整体上τ_(swell)比τ_(*swell)大2~3个量级,这意味着传统方法显著低估了涌浪的浪致雷诺应力,传统的浪致雷诺应力计算方法还有待改进。

Dependence of Estimating Whitecap Coverage on Currents and Swells

The shipboard measurements of whitecap coverage(W)and the meteorological and oceanographic information from two cruises in the South China Sea and Western Pacific are explored for estimating W.This study aims at evaluating how to im-prove the parameterizations of W while considering the effects of currents and swells on wave breaking.Currents indeed affect W in a way that winds with following currents can decrease W,whereas winds with opposing currents can increase W.Then,10-m wind speed over sea surface(U_(10))is calibrated by subtracting the current velocity from U_(10) when the propagating directions of winds and currents are aligned.By contrast,when the direction is opposite,U_(10) is calibrated by adding the parallel velocity com-ponent of the opposing current to U_(10).The power fits of W dependence on the U_(10)-related parameters of U_(10),friction velocity,wind sea Reynolds number in terms of this calibrated-U_(10) obtain better results than those directly fitted to U_(10).Different from the effect of currents on W,wind blowing along the crest line of swells may contribute to the increase in W.The conclusions suggest that U_(10) should be calibrated first before parameterizing W in areas with a strong current or some swell-dominant areas.

2023年海洋气象研究热点回眸

回顾了2022-2023年有关台风、海雾、季风、海气通量理论、海浪模拟、寒潮等海洋气象学研究进展和在此期间海洋气象观测技术的提升与发展。研究多关注于各类海洋与气象观测和模拟技术的提升,以及海洋气象灾害潜在致灾因子的形成和发展机理,例如近年来台风路径多变,快速发展的案例频发;季风、海雾、海浪、海气界面通量等的观测和发展机理研究、模式参数化改进是未来海洋气象学的重要研究方向,这些研究成果对海洋气象灾害的预测和预警提供一定的科学基础和应用价值。