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

Abstract:

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.