Search

Assured land mobility of military forces may be adversely impacted by unexpected discontinuities in terrain that fall within the relative vertical error limits of standard terrain elevation models. We define terrain gaps as consisting of such anomalies, within the context of military maneuver, having characteristic dimensions on the order of ten meters or less and minimum slope of approximately 40 degrees, which may impede or constrain the movement of manned or unmanned ground vehicles. Gaps may be natural or man-made, wet or dry, permanent or transient. They may include irrigation ditches, stream banks, short but steep escarpments, canals, walls, berms, excavation overburden, and other microterrain features with a positive or negative elevation difference from immediately surrounding terrain. We examined LIDAR (LIght Detection and Ranging) data over southwestern Montana to capture detailed elevation profiles over suspected terrain gaps, and derived geometric attributes from profile subsets to characterize gap morphology from the perspective of critical military parameters. These data were captured as geospatial information in a GIS environment containing gap linear feature classes with associated attribute data. The profile subsets for each gap feature lend themselves to automatic extraction of elevation breaklines in defining the spatial limits of the gap in the direction of maximum slope change. The distribution of gap features with attribution within the study area demonstrates the critical role that micro-terrain gaps can play in tactical military routing and maneuver models, by obviating bridging, crossing, and avoidance decisions on the ground with advance knowledge of gaps from tactical remote sensors., The original document contains color images.

The coastal cliff top line recession has historically been used to calculate erosion along the Southern Monterey Bay. Digital photogrammetry is used in this work to produce Digital Terrain Models (DTM), representing the coastal cliff top line of 1984. This links the historical recession data sets with the LIDAR measurements of 1997 and 1998 and a 2003 cliff top line measured using Kinematic DGPS. Recession time series starting in the 1940's are produced for several locations. Least square linear fits of the recession data are computed for the periods 1940-84, 1940-98 and 1940-03. At Fort Ord and Sand City the resulting slopes show a persistent erosion trend of 1 meter/year, unchanged in the last 19 years. The mean sea level (MSL) evolution is studied using historical San Francisco MSL data because of its high correlation with Monterey MSL. Higher MSL occurred during El Nino years, coincident with higher erosion rates show the correlation between erosion and MSL. In the long term, high-erosion El Nino years combine with normal years averaging to a near constant erosion trend. For Phillips Petroleum and Beach Lab, a significant decrease in the erosion rate is observed after sand mining stopped in Sand City. Digital Photogrammetry provides a high-quality representation of the shoreline topography, offering useful information to the warfighter in terms of detailed beach or landing zone characterizations., The original document contains color images.

At the request of the Chief, Cultural and Historic Resources, 36 CES/CEYN, Unit 14007 at Andersen Air Force Base (AAFB), International Archaeological Research Institute, Inc. (lARfI) has prepared a mitigation plan for development of an interpretive trail at Tarague Beach, located on the north coast of the island of Guam (Fig. 1). The interpretive trail that is the subject of this document is located in the center of the embayment and is the inland leg of a trail called "The Journey through Tarague's Past," the design of which is outlined in Volume W of The Legacy of Tarague Embayment and Its Inhabitants, Andersen AFB, Guam (Tomonari-Tuggle and Olmo 1996:107; 153-161). The trail begins at the Tarague Beach Road and extends southeast along an existing jeep road that parallels the base of the inland cliff (Fig. 2). It passes through prehistoric agricultural features and a rock shelter on the upper Tarague terrace, and then turns seaward along a prehistoric trail that crosses a zone of karrenfelds (a geological formation that is colloquially called "pit and pinnacles") and an area of pristine native forest. The trail ends in a coconut forest remaining from the days of copra plantations. A sign at the end of the 1.0 mile trail will instruct visitors to return along the same path. The purpose of this mitigation plan is to address potential impacts to significant cultural resources from the development and use of the interpretive trail. The plan is sponsored by the Department of the Army as Award No. DAMD17-00-2-0026. The U.S. Army Medical Research Acquisition Activity, 820 Chandler Street, Fort Detrick, MD 21702- 5014 is the awarding and administering acquisition office. The information content of this plan does not necessarily reflect the position or the policy of the Government, and no official endorsement is implied.

This X-File summarizes a segment of the training given by the Marine Corps Mountain Warfare Training Center on cliff assaults. It joins our other published X-Files as a reference that can be quickly read and easily transported in the cargo pocket of the utility uniform so Marines have easy-to-use information that can help them be better prepared to fight and win., Original contains color plates: All DTIC reproductions will be in black and white.

Whether from the foreshore, shoreface, shelf, or incised estuarine valleys, sedimentary deposits along the western edge of the Western Interior seaway quite uniformly record southerly directed paleoflows. Cardium Formation shoreface gravels at Willesden Green, Alberta, decrease in clast size to the southeast. Isoliths outlining clastic wedges, such as the Chalk Creek, are recurved to the south. Large-scale cross-strata in rocks considered to be either shelf sand ridges or detached shorefaces, such as the Kakwa and Musreau Members of the Cardium Formation and the Straight Cliffs Formation of southwestern Utah, indicate southerly directed paleocurrents. Estuarine incised valley-fills trend south or southeast, reflecting a high-stand shelf topography inherited by rivers as they cut across the inner shelf in response to a high-order sea-level drop. To explain this uniformity we conducted two numerical experiments that predict circulation and sediment transport paths in the seaway in response to 1) mean annual atmospheric forcing and 2) the passage of a mid-latitude winter storm. The mean annual forcing for the early Turonian is computed by GENESIS, an NCAR global climate model; the cyclone is computed using an idealized hurricane model. For the mean annual experiment, circulation of the seaway is computed using a three-dimensional, turbulent flow, coastal ocean model under the following initial and boundary conditions: (1) paleobathymetry according to a new interpretation of the litho-and bio-stratigraphy for the early Turonian; (2) fresh water runoff and precipitation-evaporation magnitudes as computed by GENESIS; (3) temperatures and salinities of the Boreal and Tethys Oceans based on GENESIS atmospheric temperatures; and 4) mean annual and daily wind stresses computed by GENESIS. For the storm experiment, circulation is forced solely by wind stresses., Department of Geosciences, Pennsylvania State University, University Park, PA 16802. SEPM special Publication n64 p179-190.

A ten-level primitive equation numerical model is used to study the influence of the ocean bottom topography in the California Current System. Five different numerical experiments were integrated for 40 days after being initialized with a baroclinic along shore coastal jet representative of the observed coastal jet. By comparison with a flat bottom case, in Experiments 1 and 3, in which the topographic slopes face westward or northward, the topography appears to have stabilizing influences on the mean flow. In experiments 2 and 4, in which the topographic slopes face southward, the topographic beta-effect appears to be strong enough so that these two cases have already reached a quasi-steady state by 40 days. This is because in Experiment 2 and 4 the long, nondispersive topographic Rossby waves are effective at transporting the eddy energy away from the source region near the coast. The resulting new mean flow appears to be stable. Keywords: Ocean currents; Ocean models; Water flow; Jet flow; Escarpments; Slopes; Longshore currents. (Theses)

Please note that if this image is under copyright, you may need to contact one or more copyright owners for any use that is not permitted under the ARTstor Terms and Conditions of Use or not otherwise permitted by law. While ARTstor tries to update contact information, it cannot guarantee that such information is always accurate. Determining whether those permissions are necessary, and obtaining such permissions, is your sole responsibility.

Please note that if this image is under copyright, you may need to contact one or more copyright owners for any use that is not permitted under the ARTstor Terms and Conditions of Use or not otherwise permitted by law. While ARTstor tries to update contact information, it cannot guarantee that such information is always accurate. Determining whether those permissions are necessary, and obtaining such permissions, is your sole responsibility.

Please note that if this image is under copyright, you may need to contact one or more copyright owners for any use that is not permitted under the ARTstor Terms and Conditions of Use or not otherwise permitted by law. While ARTstor tries to update contact information, it cannot guarantee that such information is always accurate. Determining whether those permissions are necessary, and obtaining such permissions, is your sole responsibility.

Please note that if this image is under copyright, you may need to contact one or more copyright owners for any use that is not permitted under the ARTstor Terms and Conditions of Use or not otherwise permitted by law. While ARTstor tries to update contact information, it cannot guarantee that such information is always accurate. Determining whether those permissions are necessary, and obtaining such permissions, is your sole responsibility.