Doctoral Dissertation Research: Spatial and Temporal Characteristics and Development Processes of Aeolian Sand Steamers

University Of Southern California, Los Angeles CA

Investigators

Abstract

Aeolian sand streamers, which also are known as sand snakes or windrows, are quasi-linear, streamwise concentrations of wind-blown sand. Streamers commonly are observed in natural aeolian sand-transport environments. Although these features have received minimal research attention, they can have significant consequences for the theoretical underpinnings and predictive powers of contemporary sand-transport models. Contemporary models treat aeolian sand transport as a uniform sheet of sand saltating over the bed surface. This description derives from fundamental assumptions regarding the uniformity and steadiness of the wind flow as well as assumptions regarding the homogeneity of the bed surface. The frequent occurrence of streamers in nature challenges these views and assumptions. The occurrence of streamers in aeolian environments may correspond with phenomena found in fluvial systems, leading some scientists to conclude that the spatial characteristics and temporal behavior of aeolian sand streamers should reflect theories and models of sediment transport in a variety of environments. This doctoral dissertation research project has three main objectives: (1) to quantify the shape and behavior of aeolian sand streamers, (2) to identify their origin, and (3) to determine their consequences for current aeolian transport models. These objectives will be addressed through the conduct of a set of field experiments at Oceano Dunes State Vehicle Recreation Area in central California. A variety of instruments, including cup-anemometers, hot-wire probes, saltiphones, Leatherman-type traps, and video imagery, will be deployed to measure the behavior and dimensions of streamers in conjunction with the wind-flow field and its characteristics. Sediment sampling and microsurveys will capture characteristics of the bed surface, such as micro-relief and moisture-content distribution. The integration and synthesis of experimental data will yield direct information regarding the spatial and temporal characteristics of aeolian sand streamers and will allow testing of the various hypotheses accounting for their origin. Comparison among the different types of data also will generate insights into how the presence of streamers under natural conditions affects contemporary transport models. This project aims to describe and measure a little-studied phenomenon that can have a potentially significant impact on current understandings of aeolian systems. In addition, the innovative research strategy and the use of this combination of instruments should shed a new light on issues of spatial and temporal variability and about the prediction of sediment transport in aeolian geomorphology. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.