Impact of Sea Surface Temperature on Sea Air Temperature in Tokyo Bay

It has been believed that Tokyo Bay will have more or less influence on atmospheric environmental issues such as the heat island phenomenon, heavy rainfall, and air pollution, through the land – sea breeze mechanism. However, little is known about the actual impact since there is previously no evidence to validate it. Moreover, the current model estimation of air – sea interaction is based on conventional sea surface parameters which were observed from ocean surfaces at considerably far distance from the shore. To investigate the spatial and temporal variation of Sea Surface Temperature (SST) over Tokyo Bay, an observation network has been constructed. Thermometers and water temperature gauges have been installed at 14 observation sites (lighted buoy, light beacon, offshore structure) in Tokyo Bay since November 2006, thereby observing SST and Sea Air Temperature (SAT). From recent observations in winter, the interesting results revealed that the diurnal variation of SAT is significant, and is not similar to that of SST, as contrast to the open sea. Moreover, spatial distribution of SAT is often smaller than that of SST, whereas diurnal range of SAT is larger than that of SST. The mechanism of these results will be presented at the meeting.