Comparing soil boundaries delineated by digital analysis of multispectral scanner data from high and low spatial resolution systems

The author has identified the following significant results. Computer-aided analysis techniques used with aircraft MSS data showed that the spatial resolution was sufficient to recognize each soil mapping unit of the test site. Some difficulties occurred where different soil series were intricately mixed, and this mixture showed as a separate spectral mapping unit, or where the difference between two soils depended on the depth of silty surface material. Analysis of LANDSAT data with computer-aided techniques showed that it was not possible to find spectrally homogeneous soil features of the seven soil series on the 40 ha test site on the digital display or on a picture print map. Cluster techniques could be used on an extended test area to group spectrally similar data points into cluster classes

Radiocarbon Age of Quaternary Deposits, Western Rolling Plains of Texas

Four laboratories have made more than fifty finite radiocarbon-age determinations on samples from Quaternary deposits covering a large area of the Rolling Plains. These dates span the period from the late Pleistocene Epoch (23,255 ± 2,335 yr B.P.) virtually to the present. Caran and Baumgardner (1984) described a previously unrecognized sedimentary sequence covering more than 7,800 km2 (3,000 mi2) of northwestern Texas. At the time that report was prepared, only a few relevant radiocarbon-age determinations were available. The number of reliable finite dates has now increased to more than fifty, the oldest of which is 23,255 ± 2,335 yr B.P. Older infinite dates and a few questionable finite determinations also have been obtained, some of which were reported previously by other investigators.Bureau of Economic Geolog

Aggregating available soil water holding capacity data for crop yield models

The total amount of water available to plants that is held against gravity in a soil is usually estimated as the amount present at -0.03 MPa average water potential minus the amount present at -1.5 MPa water potential. This value, designated available water-holding capacity (AWHC), is a very important soil characteristic that is strongly and positively correlated to the inherent productivity of soils. In various applications, including assessing soil moisture status over large areas, it is necessary to group soil types or series as to their productivity. Current methods to classify AWHC of soils consider only total capacity of soil profiles and thus may group together soils which differ greatly in AWHC as a function of depth in the profile. A general approach for evaluating quantitatively the multidimensional nature of AWHC in soils is described. Data for 902 soil profiles, representing 184 soil series, in Indiana were obtained from the Soil Characterization Laboratory at Purdue University. The AWHC for each of ten 150-mm layers in each soil was established, based on soil texture and parent material. A multivariate clustering procedure was used to classify each soil profile into one of 4, 8, or 12 classes based upon ten-dimensional AWHC values. The optimum number of classes depends on the range of AWHC in the population of oil profiles analyzed and on the sensitivity of a crop to differences in distribution of water within the soil profile

Quaternary Faulting in Southeastern Briscoe County, Texas

Downwarped and penecontemporaneously faulted beds of late Quaternary terrigenous sediment are well exposed in southeastern Briscoe County, Texas. Deformation probably was caused by subsidence of the Permian subcrop owing to dissolution of bedded salt at depth. Fluvial sands and gravels and lacustrine clays fill a subsidence basin, producing a locally thickened Quaternary section. A well-developed paleosol above lacustrine deposits was tilted and laterally truncated prior to modern eolian deposition at the site. Active, recently active, and inactive subsidence features are common in the western Rolling Plains of Texas. Most of these features are small, karstic sinkholes up to 330 ft (100 m) in diameter and subsidence basins a few miles long. Gustavson and others (1982) investigated more than 400 of these features (dolines) in Hall and Briscoe Counties, Texas. These structures formed and are forming as a result of dissolution of Upper Permian (Ochoan and Guadalupian) evaporites, particularly halite, at depths of 650 to 1,000 ft (200 to 300 m) (Gustavson and others, 1982; McGookey and others, in press). A similar pattern of karstic subsidence produced features of comparable size throughout late Pleistocene and Holocene time. During this interval, subsidence may have been more widespread than it is today because of the wetter climate and presumably greater rates of infiltration and transmissibility of ground water in the late Pleistocene (Carr and McGookey, in press). The moist climate of the late Pleistocene turned sinkholes and subsidence basins into pluvial ponds and lakes, the largest of which probably also received phreatic discharge. Limnic and lacustrine deposits occupy a stratigraphically consistent position in the Quaternary section of the western Rolling Plains. At one site, these deposits are more than 30 ft (9.1 m) thick and show evidence of structurally enhanced deposition.Bureau of Economic Geolog

Oxygenated organic functional groups and their sources in single and submicron organic particles in MILAGRO 2006 campaign

Fourier Transform Infrared (FTIR) and X-ray Fluorescence (XRF) were used to measure organic functional groups and elements of submicron particles collected during MILAGRO in March 2006 on three platforms: the Mexico City urban area (SIMAT), the high altitude site at 4010 m (Altzomoni), and the NCAR C130 aircraft. Scanning Transmission X-ray Microscopy (STXM) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) were applied to single particle organic functional group abundance analysis of particles simultaneously collected at SIMAT and C130. Correlations of elemental concentrations showed different groups of source-related elements at SIMAT, Altzomoni, and C130, suggesting different processes affecting the air masses sampled at the three platforms. Cluster analysis resulted in seven distinct clusters of FTIR spectra, with the last three clusters consisting of spectra collected almost exclusively on the C130 platform, reflecting the variety of sources contributing to C130 samples. Positive Matrix Factorization (PMF) of STXM-NEXAFS spectra identified three main factors representing soot, secondary, and biomass burning type spectra. PMF of FTIR spectra resulted in two fossil fuel combustion factors and one biomass burning factor, the former representative of source regions to the northeast and southwest of SIMAT. Alkane, carboxylic acid, amine, and alcohol functional groups were mainly associated with combustion related sources, while non-acid carbonyl groups were likely from biomass burning events. The majority of OM and O/C was attributed to combustion sources, although no distinction between direct emissions and atmospherically processed OM could be identified

Perturbation Analysis of the Kuramoto Phase Diffusion Equation Subject to Quenched Frequency Disorder

The Kuramoto phase diffusion equation is a nonlinear partial differential equation which describes the spatio-temporal evolution of a phase variable in an oscillatory reaction diffusion system. Synchronization manifests itself in a stationary phase gradient where all phases throughout a system evolve with the same velocity, the synchronization frequency. The formation of concentric waves can be explained by local impurities of higher frequency which can entrain their surroundings. Concentric waves in synchronization also occur in heterogeneous systems, where the local frequencies are distributed randomly. We present a perturbation analysis of the synchronization frequency where the perturbation is given by the heterogeneity of natural frequencies in the system. The nonlinearity in form of dispersion, leads to an overall acceleration of the oscillation for which the expected value can be calculated from the second order perturbation terms. We apply the theory to simple topologies, like a line or the sphere, and deduce the dependence of the synchronization frequency on the size and the dimension of the oscillatory medium. We show that our theory can be extended to include rotating waves in a medium with periodic boundary conditions. By changing a system parameter the synchronized state may become quasi degenerate. We demonstrate how perturbation theory fails at such a critical point.Comment: 22 pages, 5 figure

Assessment of methods of acquiring analyzing, and reporting crop production statistics, volume 4

There are no author-identified significant results in this report

Quaternary Stratigraphy of the Western Rolling Plains of Texas Preliminary Findings

Quaternary deposits, as much as 76 m (250 ft) thick, discontinuously cover more than 7,800 km2 (3,000 mi2) of the western Rolling Plains of northwestern Texas. The stratigraphy of this sedimentary sequence is complex, reflecting changes in paleoclimate during the late Pleistocene and Holocene Epochs. In addition, there are clear indications of syngenetic structural control of deposition and postdepositional deformation of the Quaternary strata. These effects were caused by regional and local karstic subsidence resulting from dissolution of Upper Permian evaporites, particularly halite, at depths of 120 to 240 m (400 to 800 ft). Dissolution created voids within the bedded evaporites. As the voids expanded, the overlying strata collapsed, forming depressions wherein sediment accumulated preferentially. Subsidence also caused local faulting and downwarping of some of the Quaternary deposits. Affected deposits include beds of coarse-grained sediment eroded from the westward-retreating Caprock Escarpment (adjacent to the Rolling Plains). This sediment was trapped within the zone of subsidence, forming a broad bajada at the base of the escarpment. At most sites, the coarse-elastic deposits compose the lowest of three genetic components of the regional Quaternary section.Bureau of Economic Geolog

Application of Multispectral Reflectance Studies of Soils: Pre-Landsat

It was recognized in the 1960\u27s that measuring the spectral, spatial and temporal variation of electromagnetic fields reflected and emitted from the Earth\u27s surface had many potential applications in the field of agriculture. As a result, computer-implemented pattern recognition techniques were used to analyze multispectral data for the purpose of delineating soil differences. Spectral data were obtained (1) in the laboratory by scanning soil samples with a double-beam spectrophotometer (Beckman DK-2A) and (2) in the field by scanning large areas of soils with an airborne multispectral scanner. The results obtained through this early research clearly illustrated relationships between the reflected and emitted energy from soils and other physical and chemical properties of those soils. The possibility of sampling large geographic areas and obtaining information about various soil parameters within a relatively short time period appeared to be of great value to potential users, i.e. soil surveyors, soil conservationists and other resource management personnel