National Science Foundation

This project examined the macro- and microclimatic relationships between mosquito vectors of disease, habitat, hosts, and humans in the Southwest. Researchers used unique datasets from Tucson and other semi-arid areas of the world to investigate the arid region-specific nature of WNV transmission and epidemic generation. The project aimed to: a) model the ecological niche of West Nile virus vector mosquito habitat; b) understand the characteristics of southwestern climate during the years West Nile virus had been transmitted; c) examine the re-invasion of Aedes aegypti into southern Arizona and northern Mexico; and d) develop of an appropriate model of climate-vector-host relationships for the region.

Tree-ring records of past climate not only provide paleoclimatic information about long-term natural climate variability, but are also a source of climate information that is meaningful and accessible to non-specialists. Northeastern Arizona, including Navajo and Hopi tribal lands, is an arid region that has experienced prolonged drought in recent years. People in the region rely on dryland farming and ranching, and these recent drought conditions have had serious impacts on rangelands and water supplies. Climate change will bring warmer and likely drier conditions. In this project, we will utilize three collections of tree-ring data from 1) a site in Tsegi Canyon, 2) a site south of Crown Point, and 3) one other near Fort Wingate, to develop chronologies for these tribal regions. These chronologies will provide an extended history of drought for this region under natural climate variability, which may be useful for placing the current drought in a long-term context. The ponderosa pine and Douglas-fir chronologies will be analyzed for drought information primarily for the cool season, but we will also explore the feasibility of using the latewood widths for summer moisture. The chronologies, and the climate information they contain, will be the basis for a set of outreach materials, both in the form of a handout or brief report written for a general audience, and a presentation for tribal members. Working in concert with CLIMAS team members Ferguson, Crimmins, and Garfin, and their tribal contacts, we will develop these materials in response to needs expressed by these stakeholders.

Droughts are one of the major concerns for the future of the Southwest, and yet the causes of drought in the region remain only partly understood. The situation is particularly acute when it comes to the decades-long “megadroughts” observed in the paleoclimatic record of the Southwest, and in the growing awareness that global warming is making droughts of the Southwest more acute. This project looks at the observations of current and past drought, as well as the causes and impacts of these droughts. The goal of this project is to shed new light on the observations of current and past drought, as well as the causes and impacts of these droughts, including the role of ENSO versus Atlantic sea surface temperatures in modulating drought, the exact nature of medieval megadroughts in the Four Corners, the ecological impacts of drought, the evaluation of how well climate models simulate drought, and strategies for overcoming climate model deficiencies in assessing future drought.

Climate change and variability can strongly control the population dynamics of disease vectors such as mosquitoes, altering their location and seasonality and possibly increasing the risk of disease transmission to humans. This project develops and implements a climate-based Dynamic Mosquito Simulation Model to understand and project climate effects on mosquito population dynamics and associated implications for public health, developing results that will help climate-health scientists and public health decision makers better understand and project the role of climate in actual disease cases.

This project explored innovative ways to address risk and resilience related to hydroclimatic extremes in both the upper and lower tails of streamflow probability distributions. The goal was to transfer the knowledge and record length that climate information and paleodata provide into useful tools for hydrologic decision making involving risk and resilience related to both floods and drought. Specific objectives included: (1) transfer of information from tree-ring reconstructions about past extreme streamflow episodes to water managers for integration into operations; (2) ongoing construction of a flood hydroclimatology database for linking climate, floods, and paleofloods; (3) interaction with stakeholders to develop innovative ways to use the flood database information; and (4) exploration of issues surrounding flood risk and human behavior to improve flood hazard management and flood warning practice.