Discussion of memoirs

Abstract

SUMMARYIn order to form more definite ideas regarding t h e oscillations named the North Atlantic, t h e North Pacific and t h e Southern, series of figures have been derived to express the variations of each, a n d from these have been obtained their relations with pressure, temperature, and rainfall over wide regions as well as the relations of t h e three oscillations with each other a n d with sunspots.T h e southern oscillation in t h e southern winter i s found to be extremely persistent, and its departure h a s a C.C. of '84 with t h a t of the following summer, thus providing a basis for foreshadowing seasonal conditions. T h e effects of Antarctic conditions and of Ocean temperatures a r e considered, but a satisfactory physical basis for t h e oscillations h a s still to be found. DISCUSSION Dr. G. C. SIMPSON remarked that Sir Gilbert Walker had ascribed the low temperature to the ice in Baffin Bay. H e would like himself to suggest that the ice had little effect on the temperature of the air, but that in the years of much ice there were many Nly. winds, it being the Nly. winds which brought down the ice. These Nly. winds would be cold quite irrespective of the ice and they owed their temperature to their origin and not to the ice in Baffin Bay. In the same way, he did not think that the high temperatures in Scandinavia were due to the warm sea water brought by SW. winds. The relatively high temperature in Scandinavia was due to a n increased frequency of SW. winds and had little to do with the temperature of the sea water.Sir Gilbert Walker had given the impression that the origin of the southern oscillation was variation in solar radiation. If this were true, why should not the Same case apply to the North Atlantic oscillation and the South Pacific oscillation? If all these oscillations are due to variations of solar radiation there should be a close correlation between them, but he understood that Sir Gilbert had not been able to find any clear correlation between the three oscillations. His own opinion was that a real and permanent increase of solar radiation would not necessarily result in intensifying the differences of temperature or differences of pressure between sea and land, but would rather result in a n increase of temperature throughout the whole of each zone of latitude.Dr. C. E. P. BROOKS said we owe Sir Gilbert Walker our thanks for this comprehensive discussion of the relations between the weather of distant regions. World meteorology is a complex problem, into which Sir Gilbert introduces the simplifying idea that it is dominated by three great meteorological circulations, in the North Atlantic, the North Pacific, and a third, termed the Southern Oscillation, which really covers the greater part of the world. The two northern ones are cam-

Holocene cooling culminates in sea ice oscillations in Fram Strait

“…in the Nordic Seas) has been acknowledged and documented more often (Deser et al, 2000;Dickson et al, 2000;Vinje, 2001). Given the lack of instrumental records of the NAO variability prior to 1932 (the first calculation of the NAO index dates back to 1932; Walker and Bliss, 1932) the attempts to link atmospheric fluctuations with climate changes are restricted to proxy reconstructions or numerical model experiments (e.g. Rimbu et al, 2004;Lorenz et al, 2006;Trouet et al, 2012).…”

Long-term trends in karst spring discharge and relation to climate factors and changes

“…Although the NAO occurs in all seasons, during winter it is particularly dominant, and therefore the focus of this information is on the period December through March (NAO-PC based index). Strong positive phases of the NAO-PC based index tend to be associated with above-average precipitation over northern Europe and Scandinavia in winter, and below-average precipitation over southern and central Europe; opposite patterns of precipitation anomalies are typically observed during strong negative phases of the NAO (Walker and Bliss 1932;Hurrell 1995). These data series (NAO-PC based) are available at NCARS (2020) and allow for a direct comparison with spring discharge and rainfall data series.…”

A climate index collection based on model data

“…Both versions are included in our CICMoD data set. The Southern Oscillation Index (SOI) is defined as normalized SLP differences between Tahiti (17°41 0 S, 149°27 0 W) and Darwin, Australia (12°27 0 S, 130°50 0 E) (Walker and Bliss, 1932). It is used as a measure of the large-scale fluctuations in the air pressure between the Western and Eastern Tropical Pacific and is closely related to ENSO.…”