A diagnostic analysis of the wave train propagating from high-latitudes to low-latitudes in early summer

Abstract

By using the stationary wave activity flux of Plumb (1985), the present study carried out a diagnostic analysis of the phenomenon in which a Rossby wave propagating from high to low latitudes affects the Baiu front around Japan in early summer. According to one composite and one case (during 20-29 June of 1982) analysis, there is a large horizontal southeastward component of the flux occasionally stretching from the Okhotsk Sea, via east of Japan (or Japan) to the sub-tropical region (about 25-27.5°N/155°E), when the blocking anticyclone around the Okhotsk Sea (the Okhotsk blocking anticyclone) establishes itself. On the other hand, a wide and strong ascending flux covering the area from East Siberia to the Okhotsk Sea (exactly where there is a wide and large divergence of the flux) was found during 20-29 June, 1982. These suggest that this area is one of the important forcing-source-areas for the quasistationary wave propagation, although a complete forcing mechanism of the propagation has not been found yet.