Vertical motion during the 1957 stratospheric warming

Vertical motion has been computed by the adiabatic method for (a) each of ninety locations on a grid covering most of the United States, Canada, and the adjacent North Atlantic region; (b) each of the 100-mb, 50-mb, and 25-mb levels; (c) each twice-daily observing time during the period January 16, 1957, to February 15, 1957. Until the occurrence of rapid warming, the vertical-motion patterns typically showed downward motion west of troughs and upward motion east of troughs. After the beginning of rapid warming (after January 23 at 25 mb and after February 2 at the lower levels), the vertical-motion pattern was characterized by a very large area of uniformly downward motion. Extreme magnitudes of vertical motion were about 8 cm sec−1 at 25 mb, 6 cm sec−1 at 50 mb, and 4 cm sec−1 at 100 mb. These and other results are illustrated by maps showing the distribution of height, temperature, and vertical motion at the three pressure surfaces for four selected map times.