Browsing by Author "Jones, Andrew S., author"
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Item Open Access Connecting urban food plans to the countryside: leveraging Denver's food vision to explore meaningful rural-urban linkages(Colorado State University. Libraries, 2019-04-04) Jablonski, Becca B. R., author; Carolan, Michael, author; Hale, James, author; McFadden, Dawn Thilmany, author; Love, Erin, author; Christensen, Libby, author; Covey, Tabitha, author; Bellows, Laura, author; Cleary, Rebecca, author; David, Olaf, author; Jablonski, Kevin E., author; Jones, Andrew S., author; Meiman, Paul, author; Quinn, Jason, author; Ryan, Elizabeth P., author; Schipanski, Meagan, author; Summers, Hailey, author; Uchanski, Mark, author; Sustainability, publisherCities are increasingly turning to food policy plans to support goals related to food access, food security, the environment, and economic development. This paper investigates ways that rural farmers, communities, and economies can both support and be supported by metropolitan food-focused initiatives. Specifically, our research question asked what opportunities and barriers exist to developing food policies that support urban food goals, particularly related to local procurement, as well as rural economic development. To address this question, we described and analyzed a meeting of urban stakeholders and larger-scale rural producers related to Colorado’s Denver Food Vision and Plan. We documented and explored “findings” gleaned from a supply chain diagraming and data compilation process that were then used to inform an event that brought together diverse supply chain partners. Three findings stand out. First, facilitating dialog between urban food policymakers and rural producers to understand potential tensions, mitigate such tensions, and capitalize on opportunities is essential. Second, perceptions and expectations surrounding “good food” are nuanced—a timely finding given the number of preferred procurement programs emerging across the county. Third, critical evaluation is needed across a diverse set of value chain strategies (e.g., conventional and alternative distribution) if food policy intends to support heterogeneous producers, their communities, and urban food policy goals.Item Open Access Derivation and analysis of a computationally efficient discrete Backus-Gilbert footprint-matching algorithm(Colorado State University. Libraries, 2002) Stephens, Philip J., author; Jones, Andrew S., author; Cooperative Institute for Research in the Atmosphere (Fort Collins, Colo.), publisherA computationally efficient discrete Backus-Gilbert (BG) method is derived that is subject to minimization constraints appropriate for footprint-matching applications. The method is flexible, since computational cost can be traded for accuracy. A comparison of the discrete BG method with a non-discrete BG method shows that the new method can be 250% more efficient while maintaining the same accuracy as traditional approaches. In addition, optimization approaches are used to further enhance the computational performance of the discretized BG method. A singular value decomposition approximation is applied that increases the computational efficiencies 43% to 106% while maintaining similar accuracies to the original discretized algorithm. Accuracies of the optimization were found to be scene dependent. In addition, alternative quadrature methods were also tested for several idealized simulated scenes. The results suggest that accuracy improvements could be made using customized quadrature methods that would be employed along known physical data discontinuities (such as along coastlines in microwave imagery data). In addition, regularization behaviors are also discussed; with a particular emphasis on the extension of the method for use with unnormalized gain functions. This work demonstrates that for some gain function configurations local biases can be intrinsic to the system. The flexibility of the discrete BG method allowed for several of the optimizations to be performed in a straightforward manner. Many additional optimizations are likely possible. Due to the lower computational cost of the method, this work is applicable toward applications in which noise may vary dynamically (such as in RFI-contaminated environments). The computational flexibility of the method also makes it well suited to computationally constrained problems such as 4D data assimilation of remote sensing observations.Item Open Access Microwave remote sensing of cloud liquid water and surface emittance over land regions(Colorado State University. Libraries, 1989-01) Jones, Andrew S., author; Vonder Haar, Thomas H., author; Cooperative Institute for Research in the Atmosphere (Fort Collins, Colo.), publisherMicrowave remote sensing of cloud liquid water has largely been limited to areas over ocean surfaces. This study uses data from a new microwave instrument, the SSM/I on a polar-orbiting DMSP satellite, and infrared and visible data from the VISSR instrument on the GOES satellite in geostationary orbit. The region selected for the study was an area of 500 km x 500 km centered on northeast Colorado during the first week of August 1987. The SSM/I instrument has new high frequency channels (85.5 GHz) which are more strongly attenuated by cloud liquid water than channels on previous instruments. This allows for the estimation of integrated cloud liquid water based on the microwave brightness temperature depression caused by attenuation and emission of microwave radiation at the colder cloud levels. Atmospheric attenuation due to oxygen and water vapor is determined using a millimeter-wave propagation model (MPM). The Rayleigh approximation is used for the calculation of cloud liquid water attenuation. Surface emittance measurements at the SSM/I frequencies were made with the aid of co-located GOES infrared data during clear sky conditions. Images produced of the retrieved surface emittances suggest a strong influence by wet surfaces caused by precipitation and irrigation. Error analysis results indicate absolute errors of ±0.012 for surface emittance retrievals for the 85.5 GHz channels. Integrated cloud liquid water retrievals show good qualitative agreement with other available data sources. Numerical error sensitivity analysis and comparison of integrated cloud liquid water retrievals for the vertical and horizontal polarizations show error estimates of 0.15 kg•m-2 including instrument noise. A bias between the horizontal and vertical polarizations of the 85.5 GHz channels was noticed in the retrieved integrated cloud liquid water amounts. The bias appears to be due to a relative instrument error between channels of approximately 1.5 K. Absolute error estimates of the integrated cloud liquid water retrievals are unavailable but calibration of the method should be possible if quantitative integrated cloud liquid water amounts are known.Item Open Access The use of satellite-derived heterogeneous surface soil moisture for numerical weather prediction(Colorado State University. Libraries, 1996) Jones, Andrew S., author; Department of Atmospheric Science, Colorado State University, publisher