| Popis: |
[ABSTRACT] ‘Yamase’ clouds are one of typical marine boundary-layer clouds, for which the present state-of-the-art performance of weather prediction models and general circulation models is not good enough to simulate properly the clouds, mainly because of coarse spatial-resolution of those models. Yamase clouds frequently appear over the North-Western Pacific Ocean east off the Sanriku district in summer under easterly cool winds, called Yamase, blown out from Okhotsk anti-cyclones. In order to validate numerical simulation and satellite remote sensing of Yamase clouds, we have carried out cloud observations on board the Koufu-maru of the Hakodate Marine Observatory in June of recent years. Here we discuss the optical and microphysical properties of the Yamase clouds, estimated from the shipboard observation and satellite remote sensing during the 2003 Koufu-maru cruise, in which for the first time we observed the evolution features of Yamase clouds from their formation to decade. Remote sensing using the contemporary AVHRR data from NOAA-17 in the morning orbit revealed that the Yamase clouds were rather thin, stratiform low-level clouds with an area-averaged optical thickness and effective particle radius of about 12 and 13 μm, respectively, and with a mean liquid-water-path of about 110 gm-2. |
