International Arid Lands Consortium Studies the Finer Points of Wind Erosion in Drylands
Dust Emissions from Drylands: Implications for Desertification
November 20, 2000 (Tucson, AZ)--With support from the International Arid Lands Consortium (IALC), researchers from the Desert Research Institute-Nevada and Ben Gurion University of the Negev have embarked on a three-year investigation to determine how dust in dryland areas exacerbates desertification.
Wind erosion hastens formation of deserts, primarily because the fine particles removed from the soil represent a disproportionate amount of nutrients compared with the coarse soil grains. Controlling loss of these essential fine soil particles is critical in natural landscapes as well as those areas used for agriculture. Another environmental problem is the effect of airborne dust particles on human health. Dust emissions affect the soil, the atmosphere, and the socio-economic conditions of the people living in affected areas.
The researchers propose to develop a dust emission model based on theoretical considerations that will be validated by detailed empirical field data. Researchers are producing a database that shows how soil sediments shift vertically and horizontally. They are also developing and testing a dust emission model that considers easily measurable variables in the atmosphere and on the surface of the land. The model will predict dust concentration close to the ground as a function of wind. The model will also take into account more complex variables involved in dust emission, such as changes in surface roughness during erosion events and different-sized dust particles.
A validated database is being compiled that characterizes the wind field, dust particle size distributions and mass concentrations in the bottom 10 meters of the atmosphere during dust emissions. The database also includes measurements of important surface variables such as source material particle size distributions. This data is collected using a suspended sediment sampling tower system deployed at the Owens Lake, California, playa. Owens Lake is the single largest source of dust emissions in North America and hence an ideal location to acquire the necessary data. The tower is equipped with a vertical array of instruments that monitor aerosol levels in real time, windspeed, and wind direction. An optical particle counter is used to measure the particle size distribution of the suspended dust. The collected data is used to compare the movement of dust with the observed meteorological conditions. The modeling component of this research proceeds from theoretical understanding of the dust emission process and is guided by and validated against the observational data.
This investigation contributes to management of ecological systems by providing a model that will be useful for estimating the movement of fine particles from affected areas. This will be important to determine the current levels of fine particles losses. The model can also be used to inform land managers about how fine particles losses are caused by ecosystem changes including those attributed to natural weather or to human activity.
Support for this project came from the USDA Forest Service.
The International Arid Lands Consortium (IALC) is an independent nonprofit organization dedicated to exploring the problems and solutions unique to arid and semiarid regions. IALC promotes cooperative research and practical application of new knowledge to develop sustainable ecological practices. The member institutions and their affiliates share a mission to enable people of arid lands to improve the quality of life for future generations. IALC members include the University of Arizona, Desert Research Institute-Nevada, the University of Illinois, Jewish National Fund, New Mexico State University, South Dakota State University, Texas A&M University-Kingsville, and the Higher Council for Science & Technology-Jordan. The Ministry of Agriculture & Land Reclamation-Egypt is an affiliate member.
Project Addressed in this News Release:
- 99R-03 Dust Emissions From Drylands: Implications for Desertification (Desert Research Institute-Nevada, Ben Gurion University of the Negev)