Meteorological Aspects of the 1975-76 Drought [and Discussion]

The broad scale meteorological features are examined and it is shown that the drought is related to a variety of factors, including unusual coldness in the North Pacific ocean and over Canada in the winter half-year, upper winds stronger than usual in the Central Pacific, and the quasi-biennial oscillation. Feedback mechanisms involving Atlantic sea temperatures and the drought itself helped to maintain the atmospheric mode. The additional evaporation from a reservoir in Southern England due to extra sunshine, high summer temperature, etc., is estimated. An attempt is made to put the drought into historical perspective, with the conclusion that it appears to be a rare event rather than a symptom of climatic change. Lastly, by using a Meteorological Office general circu­lation numerical model, it is shown that a large area of dry ground may inhibit rainfall: the dryness of the ground over Western Europe in the 1976 summer may have had this effect.