基于海气耦合浮标分析北欧海夏季海气热通量及其对ERA-Interim/OAFlux的评估

基于2012年我国首次在北欧海进行了23 d连续的现场浮标观测的海表面空气温度、湿度、风速和海表皮温等观测资料,利用COARE 3.5块体算法计算得到海气界面湍流热通量,感热通量为9.34 W/m~2,潜热通量为31.55 W/m~2(海洋向大气为正)。ERA-Interim和OAFlux是国际通用的海洋气象数据集,将浮标观测结果与两类数据集进行了对比分析和验证。结果显示:北欧海暖流区夏季海气温差对于海气界面的感热输送起到主要影响作用,而在中低风速(10 m/s)的情况下对潜热输送起主导作用的是海气间的湿度差。在夏季北欧海暖流区域内ERA-Interim和OAFlux相对于使用COARE计算的浮标感热通量分别偏高和偏低12.58%与26.33%,造成差异的主要因素是两个数据集对海表皮温和海表气温的估算误差;ERA-Interim和OAFlux对潜热通量分别偏高17.54%和7.76%,造成差异的原因是对海表空气湿度的估算误差。

Analysis of summer air-sea heat flux based on moored buoy observations and comparison to with the ERA-Interim/OAFlux in the Nordic Seas

In 2012 for the first time we had a 23-day continuous on-site buoy observation at the Nordic seas.Based on the observation data of sea surface air temperature, humidity, wind speed and skin temperature, the turbulence heat flux at air-sea interface was calculated by COARE 3.5 bulk algorithm. The sensible heat flux was 9.34 W/m², the latent heat flux was 31.55 W/m² (ocean to atmosphere as positive).ERA-Interim and OAFlux were international widely used oceanographic and meteorological data sets, then the buoy observation data were compared and verified with two data sets.The results show that the summer surface air-sea temperature difference in the warm area of the Nordic Seas plays a major role in the heat transfer at the air-sea interface,while in the case of low wind speed (<10m/s) in latent heat transfer the leading role is the difference between the humidity between sea and air.ERA-I and OAFlux were slightly overestimated and underestimated by 12.58% and 26.33% respectively for sensible heat fluxes in the summer warm current region of Nordic Sea. The main factors contributing to the bias are the differences between the two data sets and the buoy data for the prediction of the air temperature and the skin temperature.ERA-Interim and OAFlux have a 17.54% and 7.76% over estimate of latent heat flux respectively.The difference comes from the estimation of air & sea humidity.