7,307 research outputs found
CAT LIDAR wind shear studies
The studies considered the major meteorological factors producing wind shear, methods to define and classify wind shear in terms significant from an aircraft perturbation standpoint, the significance of sensor location and scan geometry on the detection and measurement of wind shear, and the tradeoffs involved in sensor performance such as range/velocity resolution, update frequency and data averaging interval
Maximum A Posteriori Resampling of Noisy, Spatially Correlated Data
In any geologic application, noisy data are sources of consternation for researchers, inhibiting interpretability and marring images with unsightly and unrealistic artifacts. Filtering is the typical solution to dealing with noisy data. However, filtering commonly suffers from ad hoc (i.e., uncalibrated, ungoverned) application. We present here an alternative to filtering: a newly developed method for correcting noise in data by finding the “best” value given available information. The motivating rationale is that data points that are close to each other in space cannot differ by “too much,” where “too much” is governed by the field covariance. Data with large uncertainties will frequently violate this condition and therefore ought to be corrected, or “resampled.” Our solution for resampling is determined by the maximum of the a posteriori density function defined by the intersection of (1) the data error probability density function (pdf) and (2) the conditional pdf, determined by the geostatistical kriging algorithm applied to proximal data values. A maximum a posteriori solution can be computed sequentially going through all the data, but the solution depends on the order in which the data are examined. We approximate the global a posteriori solution by randomizing this order and taking the average. A test with a synthetic data set sampled from a known field demonstrates quantitatively and qualitatively the improvement provided by the maximum a posteriori resampling algorithm. The method is also applied to three marine geology/geophysics data examples, demonstrating the viability of the method for diverse applications: (1) three generations of bathymetric data on the New Jersey shelf with disparate data uncertainties; (2) mean grain size data from the Adriatic Sea, which is a combination of both analytic (low uncertainty) and word-based (higher uncertainty) sources; and (3) side-scan backscatter data from the Martha\u27s Vineyard Coastal Observatory which are, as is typical for such data, affected by speckle noise. Compared to filtering, maximum a posteriori resampling provides an objective and optimal method for reducing noise, and better preservation of the statistical properties of the sampled field. The primary disadvantage is that maximum a posteriori resampling is a computationally expensive procedure
CRIMINAL PROCEDURE Bonds and Recognizances: Amend Provisions for Notice to Superior Court; Provide for Temporary Release of Certain Detainees
SB 255 amends existing provisions requiring notice to the superior court when a person is being held in a detention facility and is charged with an offense bailable only before a superior court judge. HB 466 creates a new section permitting the release of a person who has been found guilty of certain crimes, pending his reporting to a correction facility to serve his sentence. This release may be conditioned upon either the convicted person\u27s own recognizance or the posting of bond to ensure his return at the time for the sentence to commence
CRIMINAL PROCEDURE Bonds and Recognizances: Amend Provisions for Notice to Superior Court; Provide for Temporary Release of Certain Detainees
SB 255 amends existing provisions requiring notice to the superior court when a person is being held in a detention facility and is charged with an offense bailable only before a superior court judge. HB 466 creates a new section permitting the release of a person who has been found guilty of certain crimes, pending his reporting to a correction facility to serve his sentence. This release may be conditioned upon either the convicted person\u27s own recognizance or the posting of bond to ensure his return at the time for the sentence to commence
Continental land cover classification using meteorological satellite data
The use of the National Oceanic and Atmospheric Administration's advanced very high resolution radiometer satellite data for classifying land cover and monitoring of vegetation dynamics over an extremely large area is demonstrated for the continent of Africa. Data from 17 imaging periods of 21 consecutive days each were composited by a technique sensitive to the in situ green-leaf biomass to provide cloud-free imagery for the whole continent. Virtually cloud-free images were obtainable even for equatorial areas. Seasonal variation in the density and extent of green leaf vegetation corresponded to the patterns of rainfall associated with the inter-tropical convergence zone. Regional variations, such as the 1982 drought in east Africa, were also observed. Integration of the weekly satellite data with respect to time produced a remotely sensed assessment of biological activity based upon density and duration of green-leaf biomass. Two of the 21-day composited data sets were used to produce a general land cover classification. The resultant land cover distributions correspond well to those of existing maps
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The Bauer scarp ridge jump: a complex tectonic sequence revealed in satellite altimetry
We investigate here the ridge jump that led to abandonment of the Galapagos Rise and formation of the Batter scarp during the initiation of the present day configuration of the East Pacific Rise since the lower Miocene. We use recently available high-resolution satellite-derived gravity data to investigate in detail the tectonic structure of the eastern Pacific from the Equator to 20%. With this data, we identify fracture zones, abandoned spreading ridges, scarps, and other seafloor features that provide evidence for discerning tectonic history. Based on our structural interpretation of the satellite-derived gravity field, we make the following conclusions:
(1) The Galapagos Rise spreading center appears to have originated by opening of the Marquesas/Mendana transform complex as a result of the change in spreading direction following breakup of the Farallon Plate.
(2) The Galapagos Rise was not the sole locus of spreading following plate reorganization at ~ 20 Ma through to the initiation of the Bauer scarp at ~ 8 Ma, as had been previously hypothesized. Rather, it and a second western spreading axis were likely active concurrently, forming a counterclockwise-rotating Bauer Microplate at a much earlier stage than thought previously.
(3) The Bauer scarps are pseudofaults associated with northward rift propagation. Propagation proceeded in several stages. A first propagator emanating from the Garrett transform complex stalled at the future location of the Wilkes transform creating an area of complex morphology near its northern tip. A second propagator, also emanating from the Garrett complex followed in the first’s wake and broke through the complex region. At this point the propagation proceeded very rapidly to the northern end of the Bauer Microplate (the Gallego fracture zone, later to become the Yaquina transform fault). Ridge propagation continued north in two more stages, creating the Gofar and Quebrada transforms at the terminus of each stage
Variety and Variation
Welcome to Volume 2 of Issue 2 of Euleriana. While we occasionally discover themes that emerge from the articles and translations presented in a given issue, the wide range of Euler’s work more often results in a variety of topics for each issue. This is no less true for Issue 2
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