Fig. 1From: Cold surge event observed by radiosonde observation from the research vessel “Hakuho-maru” over the Philippine Sea in December 2012The observation sites of the radiosondes used in this study. Black circles show the launch position of the radiosondes from the R/V Hakuho-maru. The radiosonde stations at Minamidaitojima and Chichijima are indicated by green circles. The AMTEX ‘74 observation area is shown by the black polygonBack to article page