海洋热浪背景下海气湍流热通量资料的评估——以2019年东北太平洋“Blob 2.0”事件为例

Evaluation of air-sea turbulent heat fluxes data under the background of marine heatwaves—A case study of the 2019 Northeast Pacific"Blob 2.0"event

2019年夏季,东北太平洋地区经历了一次名为“Blob 2.0”的海洋热浪事件,对海洋生态系统造成了严重影响。利用美国国家数据浮标中心的浮标观测资料、全球客观分析通量产品OAFlux,以及大气再分析数据集ERA5、NCEP2和MERRA-2,综合分析了“Blob 2.0”事件期间海气湍流热通量的特征,并研究了其物理因素。浮标观测显示,在“Blob 2.0”事件期间,潜热通量呈现正增长趋势,而感热通量呈现负增长趋势,这一现象可归因于海气比湿度差呈正增长,而风速和海气温差呈负增长。评估结果表明:4种通量数据产品都低估了潜热通量的增长,ERA5的增长率与浮标最为接近。对于感热通量,MERRA-2和NCEP2产品的增长趋势与浮标观测相同,其中MERRA-2的增长率更接近;而OAFlux和ERA5产品的增长趋势与观测相反。

In the summer of 2019,the Northeastern on Pacific region experienced a marine heatwave event called"Blob 2.0",which had a significant impact on the marine ecosystem.This study conducted a comprehensive analysis of the characteristics of air-sea turbulent heat flux during this event using the buoy data from National Data Buoy Center,the global objective flux product OAFlux,and atmospheric reanalysis datasets ERA5,NCEP2 and MERRA-2.The study also investigated the physical factors influencing these fluxes.The buoy observation revealed that during the"Blob 2.0"event,there was a positive increasing trend in latent heat flux,while sensible heat flux exhibited a negative decreasing trend.This phenomenon can be attributed to the positive increase in the air-sea specific humidity difference and the negative decrease in wind speed and air-sea temperature difference.Evaluation results indicated that all four flux data products underestimated the growth of latent heat flux,with ERA5 showing the closest agreement with buoy observation.Regarding sensible heat flux,both MERRA-2 and NCEP2 products exhibited a similar increasing trend as observed by buoys,with MERRA-2 showing a closer growth rate.However,OAFlux and ERA5 products showed an opposite trend compared to the observations.