Route of Xuelong icebreaker for the 2019-2020 latitude survey, superimposed on contours of the 2018 effective vertical cutoff rigidity, calculated for May 01, 2018, at 12:00 UT. Numbers at each contour indicate the effective vertical cutoff rigidity in GV.
Histogram number: Explanation
— NM tubes in the same segment —
00: ee, same tube (tube 1 & tube 1)
01: mm, same tube (tube 2 & tube 2)
02: ee, same tube (tube 3 & tube 3)