Atmospheric circulation patterns and spatial climatic variations in Beringia

Abstract

Analyses of more than 40 years of climatic data reveal intriguing spatial variations in climatic patterns for Beringia (North-eastern Siberia and Alaska), aiding the understanding of the hierarchy of climatic controls that operate at different spatial scales within the Arctic. A synoptic climatology, using a subjective classification methodology on January and July sea level pressure, and July 500 hPa height anomaly patterns, identified 13 major atmospheric circulation patterns (26 pairs consisting of 13 synoptic/temperature and 13 synoptic/precipitation comparisons) that occur over Beringia. Composite anomaly maps of circulation, temperature, and precipitation described the spatial variability of surface climatic responses to circulation. Results indicate that nine synoptic pairs yield homogeneous surface climatic anomaly patterns throughout most of Beringia. However, many of the surface climatic responses illustrate heterogeneous anomaly patterns as a result of variations in circulation controls, such as troughing over East Asia and the Pacific subtropical high superimposed over topography, with small shifts in atmospheric circulation dramatically altering spatial variations of anomaly patterns. Distinctive contrasts in climatic responses, as suggested from ten synoptic pairs, are clearly evident for Western Beringia versus Eastern Beringia. These results offer important implications for scholars interested in assessing late Quaternary climatic change in the region from interannual to millennial timescales.

Synoptic scale controls on the δ18O in precipitation across Beringia

“…These circulation patterns vary on interannual to decadal time scales and induce characteristic responses in precipitation, sea surface temperature (SST), and surface air temperature (SAT) [Mock et al, 1998]. Climate anomalies are well expressed in coupled modes of the North Pacific Index (NPI) [Trenberth and Hurrell, 1994] and the Pacific Decadal Oscillation (PDO) [Mantua et al, 1997] and are linked to remote El Niño-Southern Oscillation forcing via rossby wave propagation from the tropical Pacific [e.g., Bjerknes, 1966;Trenberth et al, 1998].…”

Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples

“…The lake is located in a region influenced by both Siberian and North Pacific oceanic air-masses (Barr and Clark, 2011;Yanase and Abe-Ouchi, 2007;Mock et al, 1998), making it very sensitive to regional atmospheric change. The high potential of Lake El'gygytgyn as a globally significant paleoclimate and environmental archive is confirmed by numerous studies on the lake sediments formed during the past three glacial/interglacial cycles (BrighamGrette et al, 2007b;Lozhkin et al, 2007;Melles et al, 2007;Minyuk et al, 2007;Nowaczyk et al, 2007;Swann et al, 2010;Asikainen et al, 2007).…”

A 250 ka oxygen isotope record from diatoms at Lake El'gygytgyn, far east Russian Arctic

“…Furthermore, Nolan et al (2012) suggest that these weather patterns have been relatively stable with time and are likely representative of this and other interglacial periods. For Beringia, Mock et al (1998) suggest the applicability of modern synoptic climatology to paleoclimate reconstruction.…”