High-Resolution Paleoclimatology - Dendroclimatology - page 11

18 O time series of a Dongge Cave (China) stalagmite ( thin line ). Six vertical shaded
bars denote the timing of Bond events 0-5 in the North Atlantic. Two vertical gray bars (with-
out numbers) indicate two other notable weak Asian monsoon periods that can be correlated to
ice-rafted debris events. Higher frequency variability appears to be related to solar (irradiance)
forcing. NCC is the Neolithic Culture of China, which collapsed at the time indicated. ( b )Age-
depth relationship. Black error bars show 230 Th dates with 2

Fig. 1.3 ( a ) δ

errors. Two different age-depth
curves are shown, one employing linear interpolation between dated depths and the second slightly
modified by tuning to INTCAL98 within the 230 Th dating error (from Wang et al. 2005 ) . On-line
version shows this figure in color

σ

(Moberg et al. 2005 ) . This approach has much promise, and further fine-tuning will
likely lead to a better understanding of large-scale climate variability over recent
millennia.

1.8 High-Resolution Proxies: Challenges and Opportunities

High-resolution paleoclimatic records provide unique opportunities to better under-
stand the climate system because they extend the limited sampling interval that
is available from short instrumental records. This longer perspective is especially
important for studies of rare events, such as explosive volcanic eruptions or the
occurrence of extreme climatic conditions such as droughts or floods. Ice cores
reveal (through sulfate and electrical conductivity measurements) that there have
been much larger explosive volcanic eruptions in the past than during the period of
instrumental records (Zielinski et al. 1994 ; Castellano et al. 2005 ) ; by identifying
these events, it is then possible to explore the relationship between eruption size
and location and the subsequent climatic effects (e.g., D'Arrigo and Jacoby 1999 ) .
Many dendroclimatic studies have recognized the connection between explosive
eruptions and cold growing season conditions, which sometimes have led to frost
damage in trees (e.g., LaMarche and Hirschboeck 1984 ; Baillie and Munro 1988 ;
Briffa et al. 1990 ; D'Arrigo et al. 2001 ) . Proxy records of volcanic forcing also pro-
vide a much larger database of eruption events than is available for the instrumental