Publication Abstracts

Smerdon et al. 2015

Smerdon, J.E., B.I. Cook, E.R. Cook, and R. Seager, 2015: Bridging past and future climate across paleoclimatic reconstructions, observations, and models: A hydroclimate case study. J. Climate, 28, no. 8, 3212-3231, doi:10.1175/JCLI-D-14-00417.1.

Potential biases in tree-ring reconstructed Palmer drought severity index (PDSI) are evaluated using Thornthwaite (TH), Penman-Monteith (PM), and self-calibrating Penman-Monteith (SC) PDSI in three diverse regions of the United States and tree-ring chronologies from the North American drought atlas (NADA). Minimal differences are found between the three PDSI reconstructions and all compare favorably to independently reconstructed Thornthwaite-based PDSI from the NADA. Reconstructions are bridged with model-derived PDSI_TH and PDSI_PM, which both closely track modeled soil moisture (near surface and full column) during the twentieth century. Differences between modeled moisture-balance metrics only emerge in twenty-first-century projections. These differences confirm the tendency of PDSI_TH to overestimate drying when temperatures exceed the range of the normalization interval; the more physical accounting of PDSI_PM compares well with modeled soil moisture in the projection interval. Remaining regional differences in the secular behavior of projected soil moisture and PDSI_PM are interpreted in terms of underlying physical processes and temporal sampling. Results demonstrate the continued utility of PDSI as a metric of surface moisture balance while additionally providing two recommendations for future work: 1) PDSI_PM (or similar moisture-balance metrics) compare well to modeled soil moisture and are an appropriate means of representing soil-moisture balance in model simulations and 2) although PDSI_PM is more physically appropriate than PDSI_TH, the latter metric does not bias tree-ring reconstructions of past hydroclimate variability and, as such, reconstructions targeting PDSI_TH can be used with confidence in data-model comparisons. These recommendations and the collective results of this study thus provide a framework for comparing hydroclimate variability within paleoclimatic, observational, and modeled data.

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BibTeX Citation

@article{sm07100r,
  author={Smerdon, J. E. and Cook, B. I. and Cook, E. R. and Seager, R.},
  title={Bridging past and future climate across paleoclimatic reconstructions, observations, and models: A hydroclimate case study},
  year={2015},
  journal={J. Climate},
  volume={28},
  number={8},
  pages={3212--3231},
  doi={10.1175/JCLI-D-14-00417.1},
}

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RIS Citation

TY  - JOUR
ID  - sm07100r
AU  - Smerdon, J. E.
AU  - Cook, B. I.
AU  - Cook, E. R.
AU  - Seager, R.
PY  - 2015
TI  - Bridging past and future climate across paleoclimatic reconstructions, observations, and models: A hydroclimate case study
JA  - J. Climate
VL  - 28
IS  - 8
SP  - 3212
EP  - 3231
DO  - 10.1175/JCLI-D-14-00417.1
ER  -

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