南海海洋温度锋面时空特征遥感分析

Remote sensing analysis of temporal and spatial characteristicsof ocean temperature fronts in the South China Sea

摘要:

本文使用2015.5.30—2020.5.30年微波和红外融合SST数据,基于海面温度的水平变化梯度,获取了南海锋面位置、锋面平均强度及中心线长度。利用锋面信息结果,分析了南海锋面气候态分布特征和年际变化,开展锋面强度与海面风场的相关性分析。结果发现：南海区域探测到的8个锋面多为河口锋和陆架锋,均有明显的季节态变化。1、2月份检测到的锋面数量最多,所有锋面均可被检测；3~4月份有较小幅度地减少,主要体现在马来西亚-菲律宾西侧沿岸锋和泰国湾锋的消失；5~9月呈现持续减少的趋势,其中9月达到最小值,仅检测到台湾海峡及广东福建沿岸锋和越南沿岸锋；10~12月开始有所回升,南海北部沿岸锋面开始被检测到。所有锋面都在冬季风盛行时期平均强度较高,平均强度基本在0.04~0.06°C/km之间浮动。台湾海峡及广东福建沿岸锋平均梯度全年与风速的相关程度都在0.48以上,越南沿岸锋与纬向风相关系数最低为0.021。相比较夏季来说,冬季平均梯度与风速的相关程度较高。

关键词:南海;温度锋;锋面变化

Abstract:

Based on sea surface temperature (SST) data of microwave infrared fusion data from 2015.5.30—2020.5.30 ,this paper tested the temperature front in the South China Sea Region , and calculated the number of fronts ,the average intensity and the centerline length of each front statistically .Through the results of the frontal survey, we analyzed the distribution characteristics and interannual variations of the South China Sea frontal climate patterns and carried out the correlation analysis between the South China Sea temperature fronts and the monsoon. It was found that the eight fronts detected in the South China Sea region are mostly estuarine fronts and shelf fronts, all of which have obvious seasonal patterns. The number of fronts detected in January and February is the highest, and all fronts can be detected. There was a small decrease in March-April, mainly due to the disappearance of the Shelf-Slope Front and the Gulf of Thailand Front .A continuous decreasing trend was observed from May to September, with a minimum value reached in September, only the Taiwan Strait and Guangdong-Fujian Front and the Vietnam coastal front were detected ; the fronts were detected in the north of the South China Sea, and the number of fronts was increased from October to December. All fronts have higher mean intensities during the winter wind period, and the mean intensities basically fluctuate between 0.04 and 0.06°C/km, with a strong periodicity. The correlation coefficients between the mean gradient and wind speed in the Taiwan Strait and Guangdong-Fujian Front are above 0.48 throughout the year, The lowest correlation coefficient between the Vietnam Coastal Front and latitudinal winds was 0.021. The correlation coefficients between the mean gradient and wind speed in the winter are high in comparison with those in the summer.

Key words:South China Sea;temperature front;frontal change