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We report on the design, construction and operation of a new multiwavelength lidar developed for the Agricultural Research Service of the United States Department of Agriculture and its program on particle emissions from animal production facilities. The lidar incorporates a laser emitting simultaneous, pulsed Nd laser radiation at 355, 532 and 1064 nm at a PRF of 10 kHz. Lidar backscatter and extinction data are modeled to extract the aerosol information. Allreflective optics combined with dichroic and interferometric filters permit all the wavelength channels to be measured simultaneously, day or night, using photon counting by PMTs, an APD, and high speed scaling. The lidar is housed in a transportable trailer for all-weather operation at any accessible site. The laser beams are directed in both azimuth and elevation to targets of interest. We describe application of the lidar in a multidisciplinary atmospheric study at a swine production farm in Iowa. Aerosol plumes emitted from the hog barns were prominent phenomena, and their variations with temperature, turbulence, stability and feed cycle were studied, using arrays of particle samplers and turbulence detectors. Other lidar measurements focused on air motion as seen by long duration scans of the farm region. Successful operation of this lidar confirms the value of multiwavelength, eye-safe lidars for agricultural aerosol measurements.We report on a collaborative research program between the Space Dynamics Laboratory (SDL), a unit of the Utah State University Research Foundation, and the United States Department of Agriculture, Agriculture Research Service (USDA/ARS), under Cooperative Agreement 58-3625-4-12 1, to measure the emissions and dispersion of gases and particulates from agricultural operations. We plan to define the operations that generate the emissions and to identify the practices that can help mitigate those emissions. The objective of this collaboration is to work jointly to provide the data and analysis required to make increasing large scale agriculture production operations less objectionable. Specific objectives include the following: 1) develop new methods and improve existing methods of measuring emissions of particulate matter and gases from animal feeding operations, 2) develop and determine the effectiveness of management practices and control technologies to reduce emissions, and 3) develop tools to predict emissions and their dispersion across a wide range of animal production systems, management practices, and environmental conditions. APPROACHSDL and ARS are addressing these objectives in a multi-faceted program that includes a range of experimental and theoretical studies. These studies will help determine the particulate emission from livestock and cropping systems as a model system to evaluate micro meteorological models applicable to limited fetch conditions. These observations will be used to refine existing dispersion models for more realistic conditions in agriculture. We will study and support the development of technolo...