The Azimuth Project
Quasi-biennial oscillation


The quasi-biennial oscillation or QBO is a quasiperiodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months.

For more, see:

This is a:

Time–height plot of monthly-mean, zonal-mean equatorial zonal wind (u) in m/s between about 20 and 35 km (22 mi) altitude above sea level over a ten-year period. Positive values denote westerly winds and the contour line is at 0 m/s.

Possible effect on temperature anomalies

In her blog, Nadja Kutz wrote:

This concerns a discussion on Azimuth. I found that the temperature anomaly curve, which describes the global combined land [CRUTEM4] and marine [sea surface temperature (SST)] temperature anomalies (an anomaly is a deviation from a mean temperature) over time (HADCRUT4-GL) has a two-year periodicity (for more details click here). The dots in the above image shall display, why I think so. The dark line drawn over the jagged anomaly curve is the mean curve. The grey strips are one year in width. A dot highlights a peak (or at least an upward bump) in the mean curve. More precisely there are:

18 red dots which describe peaks within grey 2-year interval

5 yellow dots which describe peaks out of grey 2-year interval (two yellow peaks are rather close together)

1 uncolored dot which describes no real peak, but just a bump

4 blue dots which describe small peaks within ditches

One sees that the red and yellow dots describe more or less all peaks in the curve (the blue dots care about the minor peaks, and there is just one bump, which is not a full peak). The fact that the majority of the red and yellow dots is red, means that there is a peak every 2 years, with a certain unpreciseness which is indicated by the width of the interval.

Upon writing this post I saw that I forgot one red dot. Can you spot where?

category: climate