北極圏 北極圏限界線
a line of latitude near but to the south of the north pole it marks the northernmost point at which the sun is visible on the northern winter solstice and the southernmost point at which the midnight sun can be seen on the northern summer solstice
北極に近いが南の緯度の線 それは、太陽が北の冬至点に見える最北端と、白夜が北の夏至点に見られる最南端を示している