NAmerica2k scientific goals

Phase 2

Phase 2 had three primary science goals:

1. Incorporate a broader array of paleoclimatic information to i) extend the North America temperature reconstruction to the full continent, and to cover the full past 2000 years, and ii) to determine the features of North American paleoclimate that are most prevalent among the archive types and among reconstruction methodology, while better understanding how each proxy introduces archive-specific uncertainties and biases.

2. Develop spatially-explicit climate field reconstructions for North America, for temperature, hydroclimate parameters (e.g, precipitation, drought indices, moisture balance), and potentially pressure fields.

3. Integrate these results with suites of climate model experiments for the past 2k to better understand the climate dynamics underlying observed changes in past climate.

The first step towards achieving these goals was to pull together a well-formatted database of 2k-relevant proxy records for the continent (and nearshore ocean). NAm2k followed the PAGES2k Network-wide guidelines for proxy inclusion.

> NAmerica2k February 2014 Newsletter

Phase 1

During this phase, the group extended the Wahl and Smerdon (2012) tree-ring temperature reconstruction in temporal and spatial scope by increasing the spatial coverage to include the eastern portion of mid-latitude North America, and extending the reconstruction back to 1200 AD. This extended record was used to calibrate a 30-year resolution, pollen-based temperature reconstruction extending to 480 AD (Viau et al. 2012). These results were published in Environmental Research Letters (Trouet et al. 2013) and constituted NAmerica2k's contribution to the PAGES 2k Consortium (2013) global synthesis published in Nature Geoscience and widely cited by the IPCC-AR5 (2013).

In addition to the reconstructions, the compiled datasets were standardly formatted and are available at NOAA's World Data Center for Paleoclimatology as a resource for the community.