Influence of orography on the weather patterns and water availability of a topographically complex Chihuahuan desert region

Arid and semi-arid ecosystems cover a large extent of the planet\u27s land surface and are highly susceptible to/and dependent on resource availability patterns, especially precipitation. Topography affects large scale weather patterns and redistributes precipitation which creates a variety of microclimates in complex landscapes; how these patterns are modified, however, is still not fully understood. Climate change models for arid and semi-arid ecosystems predict a change towards more extreme precipitation events; understanding the mechanisms involved in redistributing precipitation is crucial for the protection of these areas. Indio Mountains Research Station (IMRS) is located in the northern Chihuahuan Desert and seems to exhibit the characteristics of a rainshadow area when comparing its weather to that of surrounding towns. We compared data collected from weather stations at IMRS Headquarters, six permanent or ephemeral water bodies throughout the IMRS property, and publically available data for El Paso, Pecos, Sierra Blanca, and Marfa, TX. Detailed water level data and soil cores were collected from the IMRS water bodies, as well as regional topography and hydrology ArcGIS layers. These data was used to better understand the relationship between large scale weather patterns, topography, soil particle size distribution, size and frequency of rain events, and water availability at IMRS ponds. Contrary to our predictions, IMRS does not receive significantly lower precipitation than surrounding sites, but exhibits lower wind speeds and higher average temperatures; this indicates more of an orographic than rainshadow effect of topography on the area. Temperature patterns inside IMRS were affected by elevation and aspect of each individual site, with cooler sites being at higher elevations and further to the east; also, sites on west facing slopes were warmer than expected. Elevation and orientation of each site with regards to the surrounding landscape also influenced precipitation patterns, with the drier sites being at lower and more southerly locations. Water availability at the ponds was dependent on each pond\u27s morphology, location, soil particle size distribution, and precipitation. Ponds that received more precipitation and had higher proportion of clay in the soil also held water longer; each pond\u27s morphology and location influenced the hydrology of the pond