The changing incidence of extremes in worldwide and Central England temperatures to the end of the twentieth century

Annual and seasonal gridded ocean surface temperature anomalies show an inc rease in warm extremes and a decrease in cold extremes since the late 19th century attributable entirely to the overall warming trend. Over land, howe ver, a reduction in the total incidence of extremes may reflect improved in strumental exposures. Our estimates of extremes are made by deriving percen tiles from fits of anomalies on 5 degrees latitude x 5 degrees longitude re solution to modified 2-parameter gamma distributions. A non-parametric meth od is used to check the validity of the results. Fields of percentiles crea ted using this technique can be used to map the distribution of unusual tem perature anomalies across the globe on any time scale from a month to about a decade, from 1870 onwards. We apply a similar technique to assess change s in the incidence of extreme daily Central England temperature anomalies. The incidence of these extremes, relative to individual monthly average tem peratures, has declined.