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The Asian monsoon system affects more than half of humanity worldwide, yet the dynamical processes that govern its complex spatiotemporal variability are not sufficiently understood to model and predict its behavior, due in part to inadequate long-term climate observations. Here we present the Monsoon Asia Drought Atlas (MADA), a seasonally resolved gridded(More)
Although persistent drought in West Africa is well documented from the instrumental record and has been primarily attributed to changing Atlantic sea surface temperatures, little is known about the length, severity, and origin of drought before the 20th century. We combined geomorphic, isotopic, and geochemical evidence from the sediments of Lake Bosumtwi,(More)
[1] We investigate the interpretation of tree-ring data using the Vaganov-Shashkin forward model of tree-ring formation. This model is derived from principles of conifer wood growth, and explicitly incorporates a nonlinear daily timescale model of the multivariate environmental controls on tree-ring growth. The model results are shown to be robust with(More)
The recent decades-long decline in East African rainfall suggests that multidecadal variability is an important component of the climate of this vulnerable region. Prior work based on analysing the instrumental record implicates both Indian and Pacific ocean sea surface temperatures (SSTs) as possible drivers of East African multidecadal climate(More)
[1] Tropical montane cloud forests are ecosystems intrinsically linked to a narrow range of geographic and meteorological conditions, making them potentially sensitive to small changes in precipitation or temperature. We investigate the potential application of stable isotope analysis to cloud forest dendroclimatology at Monteverde in Costa Rica in order to(More)
In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t A common research task in dendroclimatology is identification of the(More)
[1] We use a mechanistic model of tree-ring formation to simulate regional patterns of climate-tree growth relationships in the southeastern United States. Modeled chronologies are consistent with actual tree-ring data, demonstrating that our simulations have skill in reproducing broad-scale patterns of the proxy's response to climate variability. The model(More)
We develop the observational and conceptual basis for modeling conifer cambial processes as a direct but nonlinear and multivariate response to external environmental conditions. The model, here termed Vaganov-Shashkin (VS), reproduces the critical features linking climate variability to tree-ring proxy formation. We discuss recent test simulations of(More)
We use infrared, radiocarbon, and stable isotope analyses to investigate the purity of cellulose extracted from wood using a rapid processing technique. Replicate laboratory standards processed using the standard Brendel method are not significantly different with respect to delta(18)O from those prepared using traditional techniques, although the process(More)
The use of tree rings in paleoclimatology assumes that annual tree-ring growth can be reasonably approximated by a linear function of local precipitation and temperature with a set of coefficients which are temporally invariant. However, if this relationship changes over time, a climate reconstruction based on a linear model estimated for a period limited(More)
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