The Wind Trends Bulletin is a free report that evaluates deviations in global wind conditions from the historical norm on a quarterly basis. The maps contained in this report were derived from the ERA Interim reanalysis dataset (Dee, D.P., et al, 2011). The anomalies are calculated as a percent deviation from the 1988 to 2012 mean speed at 100m above ground level for the calendar quarter.
In the first quarter of 2014, wind speeds were generally below normal relative to the long-term first quarter average (1988 to 2012) across Central America, Sub- Saharan Africa, southeastern Europe, Central Asia, northern China, and Siberia. Wind speeds were above normal across much of the United States and Canada, South America, Western Europe, southern India, Indonesia, and northern Australia (Figure 1). Global wind patterns in the fi rst quarter shifted substantially from the last quarter of 2013 (Figure 2), due in part to changes in atmospheric circulation patterns.
The North Atlantic Oscillation (NAO) index was positive throughout the quarter and strongly positive in February, coinciding with a shift in the Arctic Oscillation (AO) index to negative and neutral territory. The resulting upper-level circulation pattern brought strong westerlies to Western Europe, most notably in the Iberian Peninsula, where winds were more than 20% above normal. Circulation patterns brought above normal
winds to much of North and South America as well. Persistent low pressure in the upper atmosphere over Canada and the northern U.S. was accompanied by strong winds at the surface. In South America, positive wind anomalies noted in the fourth quarter of 2013 expanded to incorporate nearly the entire continent. In Asia, winds more than 20% above normal were experienced across the Indonesian Archipelago as well as the wind power-producing state of Tamil Nadu, India.
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