Geology topics

Gayle Loren Tyree

Publications and source records attributed to Gayle Loren Tyree.

3 recordsLinked to original sources

USGS2024

Synoptic analysis and WRF-Chem model simulation of dust events in the southwestern United States

Dust transported from rangelands of the Southwestern United States (US) to mountain snowpack in the Upper Colorado River Basin during spring (March-May) forces earlier and faster snowmelt, which creates problems for water resources and agriculture. To better understand the drivers of dust events, we investigated large-scale meteorology responsible for organizing two Southwest US dust events from two different dominant geographic locations: (a) the Colorado Plateau and (b) the northern Chihuahuan Desert. High-resolution Weather Research and Forecasting coupled with Chemistry model (WRF-Chem) simulations with the Air Force Weather Agency dust emission scheme incorporating a MODIS albedo-based drag-partition was used to explore land surface-atmosphere interactions driving two dust events. We identified commonalities in their meteorological setups. The meteorological analyses revealed that Polar and Sub-tropical jet stream interaction was a common upper-level meteorological feature before each of the two dust events. When the two jet streams merged, a strong northeast-directed pressure gradient upstream and over the source areas resulted in strong near-surface winds, which lifted available dust into the atmosphere. Concurrently, a strong mid-tropospheric flow developed over the dust source areas, which transported dust to the San Juan Mountains and southern Colorado snowpack. The WRF-Chem simulations reproduced both dust events, indicating that the simulations represented the dust sources that contributed to dust-on-snow events reasonably well. The representativeness of the simulated dust emission and transport in different geographic and meteorological conditions with our use of albedo-based drag partition provides a basis for additional dust-on-snow simulations to assess the hydrologic impact in the Southwest US.

southwestern United States↗

USGS2024

Oil and gas development influences potential for dust emission from the Upper Colorado River Basin, USA

Wind erosion and dust emission from drylands have large consequences for ecosystem function and human health. Wind erosion is naturally reduced by soil crusting and sheltering by non-erodible roughness elements such as plants. Land uses that reduce surface roughness and disturb the soil surface can dramatically increase dust emission. Extraction of oil and gas is a common and growing land use in the western United States (US) that removes vegetation and other roughness elements for construction of well pads and unpaved access roads, resulting in thousands of small (1–4 ha), discrete patches of unprotected soil. Here, we use a satellite albedo-based model to assess the effect of oil/gas activity on surface roughness in the Uinta-Piceance Basin, an area of the Upper Colorado River Basin (UCRB) with dense oil and natural gas development and modelled how the change in surface roughness could impact aeolian sediment flux and dust emission. We also investigated how regional drought influences the response of surface roughness to well pads and access roads. Oil/gas activity reduced surface roughness and increased modelled aeolian sediment flux at the landscape scale across much of the study region, resulting in a modest increase of 10 139 kg of dust per year, which is small relative to dust loads from a single regional dust event observed in the region, but downwind impact could be significant. The magnitude of surface roughness reductions by oil/gas activity was generally consistent among land cover types. However, in parts of the basin that had high cover of annual forbs and grasses, oil/gas activity was associated with larger surface roughness and smaller potential dust emission. Drought decreased surface roughness across disturbed and undisturbed sites, but there was no interactive effect of oil/gas activity and drought on surface roughness. These results suggest that oil/gas activity may increase sediment fluxes and likely contributes to dust emission from landscapes in the UCRB. Understanding how drought and land use change contribute to dust emissions will benefit mitigation of undesirable impacts of wind erosion and dust transport.

Colorado, Utah↗

USGS2021

Priority species lists to restore desert tortoise and pollinator habitats in Mojave Desert shrublands

Mojave Desert shrublands are home to unique plants and wildlife and are experiencing rapid habitat change due to unprecedented large-scale disturbances; yet, established practices to effectively restore disturbed landscapes are not well developed. A priority species list of native plant taxa was developed to guide seed collectors, commercial growers, resource managers, and restoration practitioners in support of the Bureau of Land Management's Mojave Desert Native Plant Program. We identify focal plant taxa that are important for habitats of the threatened Mojave desert tortoise ( Gopherus agassizii ), a widely distributed herbivore in low and middle elevations, and pollinator taxa, including mostly Lepidopterans and Apoidean bees, some of whose populations are in decline. We identified 201 unique plant taxa in the diets of tortoises, and 49 taxa that provide thermal cover for tortoises with some overlapping taxa that provide both diet and cover. We discuss 134 native pollinators associated with plants used for nectaring, larval hosts, or cover and nesting materials. Detailed plant species accounts describing the status-of-knowledge for 57 plant taxonomic groups including detailed information on life history, ecology, and pollinator syndrome relevant to restoration success, methods of seed harvesting, propagation, and historical use in restoration. Our approach for developing a priority plant species list for the Mojave Desert provides a data-guided listing of species for restoration practitioners and identifies knowledge gaps for future investigation.

California, Nevada↗