Stratospheric wind data for Canton Island (3°S) and Nairobi, Kenya (2°S), reveal that during the period July 1955–February 1960 alternate bands of easterly and westerly winds progressed downward from the highest level of observation (30 km) at intervals of approximately 1 year, suggesting the presence of a 2‐year zonal wind oscillation in the equatorial stratosphere. The bands circle the entire globe, reach their greatest strength near 25 km, are about 10 km deep at intermediate levels, move downward at about 1 km per month, and weaken and become erratic near the tropopause. On the basis of ozone measurements it is argued that the downward propagation represents a wave motion, not a mass transport. The periodic appearance of westerly momentum at the equator suggests the presence of disturbances in the tropical stratosphere which transport momentum in a preferred manner.

Information about glacier volume and ice thickness distribution is essential for many glaciological applications, but direct measurements of ice thickness can be difficult and costly. We present a new method that calculates ice thickness via an estimate of ice flux. We solve the familiar continuity equation between adjacent flowlines, which decreases the computational time required compared to a solution on the whole grid. We test the method on Columbia Glacier, a large tidewater glacier in Alaska, USA, and compare calculated and measured ice thicknesses, with favorable results. This shows the potential of this method for estimating ice thickness distribution of glaciers for which only surface data are available. We find that both the mean thickness and volume of Columbia Glacier were approximately halved over the period 1957–2007, from 281 m to 143 m, and from 294 km3 to 134 km3, respectively. Using bedrock slope and considering how waves of thickness change propagate through the glacier, we conduct a brief analysis of the instability of Columbia Glacier, which leads us to conclude that the rapid portion of the retreat may be nearing an end.

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