Monthly mean pressure reconstruction for the Late Maunder Minimum Period (AD 1675-1715)

Abstract

The Late Maunder Minimum (LMM; 1675-1715) delineates a period with marked climate variability within the Little Ice Age in Europe. Gridded monthly mean surface pressure fields were reconstructed for this period for the eastern North Atlantic-European region (25°W-30°E and 35-70°N). These were based on continuous information drawn from proxy and instrumental data taken from several European data sites. The data include indexed temperature and rainfall values, sea ice conditions from northern Iceland and the Western Baltic. In addition, limited instrumental data, such as air temperature from central England (CET) and Paris, reduced mean sea level pressure (SLP) at Paris, and monthly mean wind direction in the Øresund (Denmark) are used. The reconstructions are based on a canonical correlation analysis (CCA), with the standardized station data as predictors and the SLP pressure fields as predictand. The CCA-based model was performed using data from the twentieth century. The period 1901-1960 was used to calibrate the statistical model, and the remaining 30 years (1961-1990) for the validation of the reconstructed monthly pressure fields. Assuming stationarity of the statistical relationships, the calibrated CCA model was then used to predict the monthly LMM SLP fields. The verification results illustrated that the regression equations developed for the majority of grid points contain good predictive skill. Nevertheless, there are seasonal and geographical limitations for which valid spatial SLP patterns can be reconstructed. Backward elimination techniques indicated that Paris station air pressure and temperature, CET, and the wind direction in the Øresund are the most important predictors, together sharing more than 65% of the total variance. The reconstructions are compared with additional data and subjectively reconstructed monthly pressure charts for the years 1675-1704. It is shown that there are differences between the two approaches. However, for extreme years the reconstructions are in good agreement.

Solar modulation of Northern Hemisphere winter blocking

“…(3) recurrent negative winter NAO values (i.e., more frequent blocking) in agreement with the reconstructions of Luterbacher et al [2000]. Note, however, that the second process does not necessarily preclude the third, since more long-lasting blocking events can coexist with fewer shortlived blocking episodes.…”

Long-term summer sunshine/moisture stress reconstruction from tree-ring widths from Bosnia and Herzegovina

“…5). This period is part of the Late Maunder Minimum and it signifies the climax of the so-called "Little Ice Age" in which Europe experienced predominant cooling ) and marked climate variability (Luterbacher et al, 2000). Summers in western and central Europe were wetter and slightly cooler than they are today due to a weaker Azores high .…”

Classifications of Atmospheric Circulation Patterns

“…Until recent years the application of objective circulation classifications in climate change studies has been confined to the 20th century because of the lack of reliable gridded data for periods reaching farther into the histor-ical past. Although automated classifications have been applied to subjectively reconstructed pressure fields for outstanding historical periods, like the Late Maunder Minimum, 127 only the development of objectively reconstructed gridded SLP data for the North Atlantic-European region 3,97,99,128,130 with varying temporal and spatial resolution and covering varying periods of the historical past gave rise to thorough investigations of long-term circulation variations by means of objective classifications. The application of nonhierarchical clustering to reconstructed SLP data for the Late Maunder Minimum 128 and observed SLP data for the 1961-1990 period was used as a tool for comparing circulation dynamics between the two periods.…”