In this Section:

	Background
	Project Overview
	Research Methods
	Project Status
	Reconstruction Data
	References
	Related Links
	Contacts

Annual growth rings in trees have been used to reconstruct Southwest climate back to AD 1000.

Research and Products:
Reconstructing Past Climate in the Southwest

Project Overview

This project focuses on several research goals:

• Developing cool-season precipitation reconstructions for climate divisions in Arizona and New Mexico.
  
• Assessing the utility of two techniques, linear regression and neural networks, for developing climate reconstructions.
  
• Summarizing past drought with respect to conditions during the 20th century.
  
• Downscaling paleoclimate information.

This research uses tree-growth information collected from hundreds on trees growing at 19 sites (Figure 2) to reconstruct total cool-season precipitation (November-April) back to AD 1000.

Figure 2. Location of tree-ring sites. [more details]

Individual reconstructions were developed for each of the NCDC climate divisions in Arizona and New Mexico (Figure 3). These reconstructions provide important information regarding the variability of precipitation at a time scale longer than that recorded by rain gauges. They also provide information on long-term variability of precipitation in the Southwest (Figure 4).

Figure 4. An example of the reconstructed cool-season precipitation. [more details]