2007 Annual Report 1a.Objectives (from AD-416) 1. To characterize the surface properties of the dry lakebed of Lake Texcoco to determine WEPS input parameters and potential amount of PM10 generation from the surface soils. 2. To asses the amount and frequency of the PM10 wind erosion material emitted from the dry lakebed of Lake Texcoco. 3. To train a UNAM scientist in wind erosion sampling and analysis techniques and collaborate on analysis of data from Objectives 1&2 for use with a coupled WEPS and MCCM model. 1b.Approach (from AD-416) 1. Select two sites in the wind erosion prone area of Lake Texcoco which are the source of fine particulates. At each site, surface soils will be sampled with three replicates. Field erodibility analysis will be performed on soil conditions at the beginning each erosion season. 2. One or two sites will be selected on Lake Texcoco which typify erodible surfaces of the lake and are likely to erode (corresponding to sites for Objective 1). Sites will be as nearly level as possible with a minimum 200 meters of fetch in the dominant wind direction for the period. At each site, four towers will be placed in the field consisting of BSNE (Fryrear, 1986) and TSI erosion sampling equipment. Each tower will consist of five BSNE type samplers each with openings at heights 0.05, 0.10, 0.35, 0.60, and 1.0 meters and one TSI sampler at 2 meters above the soil surface. One tower will be in the upwind position and three towers will be situated 100-200 meters downwind from the upwind tower to provide differences in sediment flux in the prevailing wind direction. The sampling devices will be supplied by WERU. The support towers for the sampling devices will be supplied by UNAM. The samplers will be in place for the approximate wind erosion season of March and April. 3. A UNAM scientist will be trained in evaluating soil surface properties for determining WEPS input parameters and PM10 generation potential of the surface soils (Objective. 1)in the field. A WERU scientist will travel to the field study site before the erosion season to assist and train UNAM scientists on sampling setup and monitoring techniques (Objective 2). UNAM scientist and WERU scientists will collaborate on analysis of data from Objectives 1&2 for use with a coupled WEPS-MCCM model. 3.Progress Report This report documents research conducted under a Non-Funded Cooperative Agreement between ARS and Universidad Nacional Autonoma Coyoacan. Additional details of research can be found in the report for the in-couse associated project CRIS 5430-11120-007-00D, Particulate Emissions From Wind Erosion: Processes, Assessment, and Control. ARS scientist participated in collaborative research with scientists of the Center for Atmospheric Science at the National Autonomous University of Mexico (UNAM) on March 25-31, 2007. ARS participation consisted of presenting a seminar titled “Wind Erosion: Processes, Control, and Simulation” to UNAM scientists and graduate students, assisting in the installation of wind erosion field equipment on an agricultural field, and sampling and describing the soil surface erodibility for the Wind Erosion Prediction System (WEPS). In addition, discussions were held on the current study as well as future collaboration. Erodibility analysis of soil samples from the field site was conducted at the USDA-ARS Wind Erosion Research Unit. The use of satellite imagery for identifying dust sources in the Valley of Mexico was also investigated. Methods of monitoring this project included, discussing project plans, reviewing program goals and accomplishments with the Cooperator’s PI via e-mail and written correspondence; e-mail or other types of written correspondence; providing technical advice to Cooperator’s personnel; and, conducting site visits at Cooperator’s facilities.