Measuring the Non-Line-of-Sight Ultra-High-Frequency Channel in Mountainous Terrain: A Spread-Spectrum, Portable Channel Sounder

DTIC Science & Technology

2018-03-01

ER D C/ CR RE L TR -1 8- 3 ERDC 6.1 Basic Research Measuring the Non-Line-of-Sight Ultra- High - Frequency Channel in Mountainous Terrain... High - Frequency Channel in Mountainous Terrain A Spread-Spectrum, Portable Channel Sounder Samuel S. Streeter and Daniel J. Breton U.S. Army...spread-spectrum, portable channel sounder specifically designed to meas- ure the non-line-of-sight, ultra- high -frequency channel in mountainous terrain

Challenges in Understanding and Forecasting Winds in Complex Terrain.

NASA Astrophysics Data System (ADS)

Mann, J.; Fernando, J.; Wilczak, J. M.

2017-12-01

An overview will be given of some of the challenges in understanding and forecasting winds in complex terrain. These challenges can occur for several different reasons including 1) gaps in our understanding of fundamental physical boundary layer processes occurring in complex terrain; 2) a lack of adequate parameterizations and/or numerical schemes in NWP models; and 3) inadequate observations for initialization of NWP model forecasts. Specific phenomena that will be covered include topographic wakes/vortices, cold pools, gap flows, and mountain-valley winds, with examples taken from several air quality and wind energy related field programs in California as well as from the recent Second Wind Forecast Improvement Program (WFIP2) field campaign in the Columbia River Gorge/Basin area of Washington and Oregon States. Recent parameterization improvements discussed will include those for boundary layer turbulence, including 3D turbulence schemes, and gravity wave drag. Observational requirements for improving wind forecasting in complex terrain will be discussed, especially in the context of forecasting pressure gradient driven gap flow events.

Modeling and Visualizing Flow of Chemical Agents Across Complex Terrain

NASA Technical Reports Server (NTRS)

Kao, David; Kramer, Marc; Chaderjian, Neal

2005-01-01

Release of chemical agents across complex terrain presents a real threat to homeland security. Modeling and visualization tools are being developed that capture flow fluid terrain interaction as well as point dispersal downstream flow paths. These analytic tools when coupled with UAV atmospheric observations provide predictive capabilities to allow for rapid emergency response as well as developing a comprehensive preemptive counter-threat evacuation plan. The visualization tools involve high-end computing and massive parallel processing combined with texture mapping. We demonstrate our approach across a mountainous portion of North California under two contrasting meteorological conditions. Animations depicting flow over this geographical location provide immediate assistance in decision support and crisis management.

Improved mapping of National Atmospheric Deposition Program wet-deposition in complex terrain using PRISM-gridded data sets

USGS Publications Warehouse

Latysh, Natalie E.; Wetherbee, Gregory Alan

2012-01-01

High-elevation regions in the United States lack detailed atmospheric wet-deposition data. The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) measures and reports precipitation amounts and chemical constituent concentration and deposition data for the United States on annual isopleth maps using inverse distance weighted (IDW) interpolation methods. This interpolation for unsampled areas does not account for topographic influences. Therefore, NADP/NTN isopleth maps lack detail and potentially underestimate wet deposition in high-elevation regions. The NADP/NTN wet-deposition maps may be improved using precipitation grids generated by other networks. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) produces digital grids of precipitation estimates from many precipitation-monitoring networks and incorporates influences of topographical and geographical features. Because NADP/NTN ion concentrations do not vary with elevation as much as precipitation depths, PRISM is used with unadjusted NADP/NTN data in this paper to calculate ion wet deposition in complex terrain to yield more accurate and detailed isopleth deposition maps in complex terrain. PRISM precipitation estimates generally exceed NADP/NTN precipitation estimates for coastal and mountainous regions in the western United States. NADP/NTN precipitation estimates generally exceed PRISM precipitation estimates for leeward mountainous regions in Washington, Oregon, and Nevada, where abrupt changes in precipitation depths induced by topography are not depicted by IDW interpolation. PRISM-based deposition estimates for nitrate can exceed NADP/NTN estimates by more than 100% for mountainous regions in the western United States.

Improved mapping of National Atmospheric Deposition Program wet-deposition in complex terrain using PRISM-gridded data sets.

PubMed

Latysh, Natalie E; Wetherbee, Gregory Alan

2012-01-01

High-elevation regions in the United States lack detailed atmospheric wet-deposition data. The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) measures and reports precipitation amounts and chemical constituent concentration and deposition data for the United States on annual isopleth maps using inverse distance weighted (IDW) interpolation methods. This interpolation for unsampled areas does not account for topographic influences. Therefore, NADP/NTN isopleth maps lack detail and potentially underestimate wet deposition in high-elevation regions. The NADP/NTN wet-deposition maps may be improved using precipitation grids generated by other networks. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) produces digital grids of precipitation estimates from many precipitation-monitoring networks and incorporates influences of topographical and geographical features. Because NADP/NTN ion concentrations do not vary with elevation as much as precipitation depths, PRISM is used with unadjusted NADP/NTN data in this paper to calculate ion wet deposition in complex terrain to yield more accurate and detailed isopleth deposition maps in complex terrain. PRISM precipitation estimates generally exceed NADP/NTN precipitation estimates for coastal and mountainous regions in the western United States. NADP/NTN precipitation estimates generally exceed PRISM precipitation estimates for leeward mountainous regions in Washington, Oregon, and Nevada, where abrupt changes in precipitation depths induced by topography are not depicted by IDW interpolation. PRISM-based deposition estimates for nitrate can exceed NADP/NTN estimates by more than 100% for mountainous regions in the western United States.

Wintertime slope winds and its turbulent characteristics in the Yeongdong region of Korea

NASA Astrophysics Data System (ADS)

Jeon, H. R.; Eun, S. H.; Kim, B. G.; Lee, Y. H.

2015-12-01

The Yeongdong region has various meteorological phenomenons by virtue of complicated geographical characteristics with high Taebaek Mountains running from the north to the south and an adjacent East Sea to the east. There are few studies on the slope winds and its turbulent characteristics over the complex terrain, which are critical information in mountain climbing, hiking, paragliding, even winter sports such as alpine skiing and ski jump etc. For the understanding of diverse mountain winds in the complex terrain in Yeongdong, hot-wire anemometers (Campbell Scientific) have been installed at a couple of sites since October 2014 and several automatic weather stations at several sites around the mountainous region in Yeongdong since November 2012.WRF model simulations have been also done with an ultra-fine horizontal resolution of 300 m for 10 years. Generally, model and observation show that the dominant wind is westerly, approximately more than 75%. It is quite consistent that wind fields from both model and observation agree with each other in the valley region and at the top of the mountain, but there is a significant disagreement in wind direction specifically in the slide slope. Probably this implies model's performance with even an ultra-fine resolution is still not enough for the slide slope domain of complex terrains. Despite that, the observation clearly showed up- and down slope winds for the weak synoptic conditions carefully selected such as strong insolation and a synoptic wind less than 5m/s in the 850 hPa. The up- and down slope flows are also demonstrated in the snow-covered condition as well as grass ground. Further, planar fit transformation algorithm against the coordinate tilt has been applied to raw wind data (10Hz) of the slope site for the analysis of turbulence properties. Turbulence also increases with synoptic wind strength. Detailed analysis of mechanical turbulence and buoyance will be discussed for different surface properties (grass or snow), and wind strength (weak and strong).

Analysis of the inversion monitoring capabilities of a monostatic acoustic radar in complex terrain. [Tennessee River Valley

NASA Technical Reports Server (NTRS)

Koepf, D.; Frost, W.

1981-01-01

A qualitative interpretation of the records from a monostatic acoustic radar is presented. This is achieved with the aid of airplane, helicopter, and rawinsonde temperature soundings. The diurnal structure of a mountain valley circulation pattern is studied with the use of two acoustic radars, one located in the valley and one on the downwind ridge. The monostatic acoustic radar was found to be sufficiently accurate in locating the heights of the inversions and the mixed layer depth to warrant use by industry even in complex terrain.

WNDCOM: estimating surface winds in mountainous terrain

Treesearch

Bill C. Ryan

1983-01-01

WNDCOM is a mathematical model for estimating surface winds in mountainous terrain. By following the procedures described, the sheltering and diverting effect of terrain, the individual components of the windflow, and the surface wind in remote mountainous areas can be estimated. Components include the contribution from the synoptic scale pressure gradient, the sea...

Environmental impacts of forest road construction on mountainous terrain

PubMed Central

2013-01-01

Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2) and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both steep terrain (30-50% gradient) and very steep terrain (51-80% gradient). Bulldozers and hydraulic excavators were determined to be the main machines for forest road construction, causing environmental damage and cross sections in mountainous areas. As a result of this study, the percent damage to forests was determined as follows: on steep terrain, 21% of trees were damaged by excavators and 33% of trees were damaged by bulldozers during forest road construction, and on very steep terrain, 27% of trees were damaged by excavators and 44% of trees were damaged by bulldozers during forest road construction. It was also determined that on steep terrain, when excavators were used, 12.23% less forest area was destroyed compared with when bulldozers were used and 16.13% less area was destroyed by excavators on very steep terrain. In order to reduce the environmental damage on the forest ecosystem, especially in steep terrains, hydraulic excavators should replace bulldozers in forest road construction activities. PMID:23497078

Assessment of the Suitability of High Resolution Numerical Weather Model Outputs for Hydrological Modelling in Mountainous Cold Regions

NASA Astrophysics Data System (ADS)

Rasouli, K.; Pomeroy, J. W.; Hayashi, M.; Fang, X.; Gutmann, E. D.; Li, Y.

2017-12-01

The hydrology of mountainous cold regions has a large spatial variability that is driven both by climate variability and near-surface process variability associated with complex terrain and patterns of vegetation, soils, and hydrogeology. There is a need to downscale large-scale atmospheric circulations towards the fine scales that cold regions hydrological processes operate at to assess their spatial variability in complex terrain and quantify uncertainties by comparison to field observations. In this research, three high resolution numerical weather prediction models, namely, the Intermediate Complexity Atmosphere Research (ICAR), Weather Research and Forecasting (WRF), and Global Environmental Multiscale (GEM) models are used to represent spatial and temporal patterns of atmospheric conditions appropriate for hydrological modelling. An area covering high mountains and foothills of the Canadian Rockies was selected to assess and compare high resolution ICAR (1 km × 1 km), WRF (4 km × 4 km), and GEM (2.5 km × 2.5 km) model outputs with station-based meteorological measurements. ICAR with very low computational cost was run with different initial and boundary conditions and with finer spatial resolution, which allowed an assessment of modelling uncertainty and scaling that was difficult with WRF. Results show that ICAR, when compared with WRF and GEM, performs very well in precipitation and air temperature modelling in the Canadian Rockies, while all three models show a fair performance in simulating wind and humidity fields. Representation of local-scale atmospheric dynamics leading to realistic fields of temperature and precipitation by ICAR, WRF, and GEM makes these models suitable for high resolution cold regions hydrological predictions in complex terrain, which is a key factor in estimating water security in western Canada.

Geo-Hazards and Mountain Road Development in Nepal: Understanding the Science-Policy-Governance Interface

NASA Astrophysics Data System (ADS)

Dugar, Sumit; Dahal, Vaskar

2015-04-01

The foothills of Nepalese Himalayas located in the neotectonic mountain environment are among some of the most unstable and geomorphologically dynamic landscapes in the world. Young fold mountains in this region are characterized by complex tectonics that influence the occurrence of earthquakes, while climatic processes such as intense orographic rainfall often dictate the occurrence of floods and landslides. Development of linear infrastructures, such as roads, in mountainous terrain characterized by high relief and orogeny is considerably challenging where the complexity of landscape in steep and irregular topography, difficult ground conditions and weak geology, presents engineers and planners with numerous difficulties to construct and maintain mountain roads. Whilst application of engineering geology, geomorphic interpretation of terrain in terms of physiography and hydrology, and identification of geo-hazards along the road corridor is critical for long term operation of mountain roads, low-cost arterial roads in the Himalayan foothills generally fail to incorporate standard road slope engineering structures. This research provides unique insights on policy and governance issues in developing mountainous countries such as Nepal, where achieving a sound balance between sustainability and affordability is a major challenge for road construction. Road development in Nepal is a complex issue where socio-economic and political factors influence the budget allocation for road construction in rural hilly areas. Moreover, most mountain roads are constructed without any geological or geo-technical site investigations due to rampant corruption and lack of adequate engineering supervision. Despite having good examples of rural road construction practices such as the Dharan-Dhankuta Road in Eastern Nepal where comprehensive terrain-evaluation methods and geo-technical surveys led to an improved understanding of road construction, learnings from this project have not informed other road development schemes in Nepal. Geomorphological surveys and robust geo-hazard assessments that factor the spatial and temporal dimensions of the seismic, fluvial and sediment hazards along the road corridor are critical for sustainable development of mountain roads. However, scientific and technical research studies seldom inform mountain road development primarily due to lack of co-ordination between the respective government agencies, access to journal papers in developing countries and unwillingness to adopt novel interventions in rural road construction practices. These challenges are further exacerbated by weak governance and lack of proper policy enforcement that often leads to construction of poorly engineered roads, thereby increasing the risk of rural infrastructural damage from geo-hazards. Though there exists a disconnect between the science-policy-governance interface where information on geo-hazards is neglected in mountain road development due to lack of scientific research and government apathy, there is an opportunity to spur dialogue and sensitize these issues via trans-disciplinary approaches on disaster risk management.

Earthquake fragility assessment of curved and skewed bridges in Mountain West region.

DOT National Transportation Integrated Search

2016-09-01

Reinforced concrete (RC) bridges with both skew and curvature are common in areas with : complex terrains. Skewed and/or curved bridges were found in existing studies to exhibit more : complicated seismic performance than straight bridges, however th...

Evaluation of a CFD-based Wind Model Optimized for ABL Flows: Comparisons with Observations from a Tall Isolated Mountain

NASA Astrophysics Data System (ADS)

Wagenbrenner, N. S.; Forthofer, J.; Butler, B.

2015-12-01

Near-surface wind predictions are important for a number of applications, including transport and dispersion, wind energy forecasting, and wildfire behavior. Researchers and forecasters would benefit from a wind model that could be readily applied to complex terrain for use in these disciplines. Unfortunately, near-surface winds in complex terrain are not handled well by traditional modeling approaches. Computational fluid dynamics (CFD) models are increasingly being applied to simulate atmospheric boundary layer (ABL) flows, especially in wind energy applications; however, the standard functionality provided in commercial CFD models is not suitable for ABL flows. Appropriate CFD modeling in the ABL requires modification of empirically-derived wall function parameters and boundary conditions to avoid erroneous streamwise gradients due to inconsistences between inlet profiles and specified boundary conditions. This work presents a new version of a wind model, WindNinja, developed for wildfire applications in complex terrain. The new version offers two options for flow simulations: 1) the native, fast-running mass-consistent method available in previous versions and 2) a CFD approach based on the OpenFOAM toolbox and optimized for ABL flows. The model is described and evaluations of predictions with surface wind data collected from a recent field campaign at a tall isolated mountain are presented. CFD models have typically been evaluated with data collected from relatively simple terrain (e.g., low-elevation hills such as Askervein and Bolund) compared to the highly rugged terrain found in many regions, such as the western U.S. Here we provide one of the first evaluations of a CFD model over real terrain with ruggedness approaching that of landscapes characteristic of the western U.S. and other regions prone to wildfire. A comparison of predictions from the native mass-consistent method and the new CFD method is provided.

Impact of land surface conditions on the predictability of hydrologic processes and mountain-valley circulations in the North American Monsoon region

NASA Astrophysics Data System (ADS)

Xiang, T.; Vivoni, E. R.; Gochis, D. J.; Mascaro, G.

2015-12-01

Heterogeneous land surface conditions are essential components of land-atmosphere interactions in regions of complex terrain and have the potential to affect convective precipitation formation. Yet, due to their high complexity, hydrologic processes over mountainous regions are not well understood, and are usually parameterized in simple ways within coupled land-atmosphere modeling frameworks. With the improving model physics and spatial resolution of numerical weather prediction models, there is an urgent need to understand how land surface processes affect local and regional meteorological processes. In the North American Monsoon (NAM) region, the summer rainy season is accompanied by a dramatic greening of mountain ecosystems that adds spatiotemporal variability in vegetation which is anticipated to impact the conditions leading to convection, mountain-valley circulations and mesoscale organization. In this study, we present results from a detailed analysis of a high-resolution (1 km) land surface model, Noah-MP, in a large, mountainous watershed of the NAM region - the Rio Sonora (21,264 km2) in Mexico. In addition to capturing the spatial variations in terrain and soil distributions, recently-developed features in Noah-MP allow the model to read time-varying vegetation parameters derived from remotely-sensed vegetation indices; however, this new implementation has not been fully evaluated. Therefore, we assess the simulated spatiotemporal fields of soil moisture, surface temperature and surface energy fluxes through comparisons to remote sensing products and results from coarser land surface models obtained from the North American Land Data Assimilation System. We focus attention on the impact of vegetation changes along different elevation bands on the diurnal cycle of surface energy fluxes to provide a baseline for future analyses of mountain-valley circulations using a coupled land-atmosphere modeling system. Our study also compares limited streamflow observations in the large watershed to simulations using the terrain and channel routing when Noah-MP is run within the WRF-Hydro modeling framework, with the goals of validating the rainfall-runoff partitioning and translating the spatiotemporal mountain processes into improvements in streamflow predictions.

Winds, Mountains, and Wildland Fire: Improved Understanding of Coupled Atmosphere-Topography-Fire Interactions Through Large-Eddy Simulation

NASA Astrophysics Data System (ADS)

Munoz-Esparza, D.; Sauer, J.; Linn, R.

2015-12-01

Anomalous and unexpected fire behavior in complex terrain continues to result in substantial loss of property and extremely dangerous conditions for firefighting field personnel. We briefly discuss proposed hypotheses of fire interactions with atmospheric flows over complex terrain that can lead to poorly-understood and potentially catastrophic scenarios. Then, our recent results of numerical investigations via large-eddy simulation of coupled atmosphere-topography-fire phenomenology with the Los Alamos National Laboratory, HiGrad-Firetec model are presented as an example of the potential for increased understanding of these complex processes. This investigation focuses on the influence of downslope surface wind enhancement through stably stratified flow over an isolated hill, and the resulting dramatic changes in fire behavior including spread rate, and intensity. Implications with respect to counter-intuitive fire behavior and extreme fire events are discussed. This work demonstrates a tremendous opportunity to immediately create safer and more effective policy for field personnel through improved predictability of atmospheric conditions over complex terrain

High-resolution dust modelling over complex terrains in West Asia

NASA Astrophysics Data System (ADS)

Basart, S.; Vendrell, L.; Baldasano, J. M.

2016-12-01

The present work demonstrates the impact of model resolution in dust propagation in a complex terrain region such as West Asia. For this purpose, two simulations using the NMMB/BSC-Dust model are performed and analysed, one with a high horizontal resolution (at 0.03° × 0.03°) and one with a lower horizontal resolution (at 0.33° × 0.33°). Both model experiments cover two intense dust storms that occurred on 17-20 March 2012 as a consequence of strong northwesterly Shamal winds that spanned over thousands of kilometres in West Asia. The comparison with ground-based (surface weather stations and sunphotometers) and satellite aerosol observations (Aqua/MODIS and MSG/SEVIRI) shows that despite differences in the magnitude of the simulated dust concentrations, the model is able to reproduce these two dust outbreaks. Differences between both simulations on the dust spread rise on regional dust transport areas in south-western Saudi Arabia, Yemen and Oman. The complex orography in south-western Saudi Arabia, Yemen and Oman (with peaks higher than 3000 m) has an impact on the transported dust concentration fields over mountain regions. Differences between both model configurations are mainly associated to the channelization of the dust flow through valleys and the differences in the modelled altitude of the mountains that alters the meteorology and blocks the dust fronts limiting the dust transport. These results demonstrate how the dust prediction in the vicinity of complex terrains improves using high-horizontal resolution simulations.

An All Sky Instantaneous Shortwave Solar Radiation Model for Mountainous Terrain

NASA Astrophysics Data System (ADS)

Zhang, S.; Li, X.; She, J.

2017-12-01

In mountainous terrain, solar radiation shows high heterogeneity in space and time because of strong terrain shading effects and significant variability of cloud cover. While existing GIS-based solar radiation models simulate terrain shading effects with relatively high accuracy and models based on satellite datasets consider fine scale cloud attenuation processes, none of these models have considered the geometrical relationships between sun, cloud, and terrain, which are important over mountainous terrain. In this research we propose sky cloud maps to represent cloud distribution in a hemispherical sky using MODIS cloud products. By overlaying skyshed (visible area in the hemispherical sky derived from DEM), sky map, and sky cloud maps, we are able to consider both terrain shading effects and anisotropic cloud attenuation in modeling instantaneous direct and diffuse solar radiation in mountainous terrain. The model is evaluated with field observations from three automatic weather stations in the Tizinafu watershed in the Kunlun Mountains of northwestern China. Overall, under all sky conditions, the model overestimates instantaneous global solar radiation with a mean absolute relative difference (MARD) of 22%. The model is also evaluated under clear sky (clearness index of more than 0.75) and partly cloudy sky (clearness index between 0.35 and 0.75) conditions with MARDs of 5.98% and 23.65% respectively. The MARD for very cloudy sky (clearness index less than 0.35) is relatively high. But these days occur less than 1% of the time. The model is sensitive to DEM data error, algorithms used in delineating skyshed, and errors in MODIS atmosphere and cloud products. Our model provides a novel approach for solar radiation modeling in mountainous areas.

Turbulence sources in mountain terrain: results from MATERHORN program

NASA Astrophysics Data System (ADS)

Di Sabatino, Silvana; Leo, Laura S.; Fernando, Harindra J. S.; Pardyjak, Eric R.; Hocut, Chris M.

2016-04-01

Improving high-resolution numerical weather prediction in complex terrain is essential for the many applications involving mountain weather. It is commonly recognized that high intensity weather phenomena near mountains are a safety hazard to aircrafts and unmanned aerial vehicles, but the prediction of highly variable weather is often unsatisfactory due to inadequacy of resolution or lack of the correct dynamics in the model. Improving mountain weather forecasts has been the goal of the interdisciplinary Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program (2011-2016). In this paper, we will report some of the findings focusing on several mechanisms of generating turbulence in near surface flows in the vicinity of an isolated mountain. Specifically, we will discuss nocturnal flows under low synoptic forcing. It has been demonstrated that such calm conditions are hard to predict in typical weather predictions models where forcing is dominated by local features that are poorly included in numerical models. It is found that downslope flows in calm and clear nights develop rapidly after sunset and usually persists for few hours. Owing to multiscale flow interactions, slope flows appear to be intermittent and disturbed, with a tendency to decay through the night yet periodically and unexpectedly generated. One of the interesting feature herein is the presence of oscillations that can be associated to different types of waves (e.g. internal and trapping waves) which may break to produce extra mixing. Pulsations of katabatic flow at critical internal-wave frequency, flow intrusions arriving from different topographies and shear layers of flow fanning out from the gaps all contribute to the weakly or intermittently turbulent state. Understanding of low frequency contributions to the total kinetic energy represent a step forward into modelling sub-grid effects in numerical models used for aviation applications.

Sink detection on tilted terrain for automated identification of glacial cirques

NASA Astrophysics Data System (ADS)

Prasicek, Günther; Robl, Jörg; Lang, Andreas

2016-04-01

Glacial cirques are morphologically distinct but complex landforms and represent a vital part of high mountain topography. Their distribution, elevation and relief are expected to hold information on (1) the extent of glacial occupation, (2) the mechanism of glacial cirque erosion, and (3) how glacial in concert with periglacial processes can limit peak altitude and mountain range height. While easily detectably for the expert's eye both in nature and on various representations of topography, their complicated nature makes them a nemesis for computer algorithms. Consequently, manual mapping of glacial cirques is commonplace in many mountain landscapes worldwide, but consistent datasets of cirque distribution and objectively mapped cirques and their morphometrical attributes are lacking. Among the biggest problems for algorithm development are the complexity in shape and the great variability of cirque size. For example, glacial cirques can be rather circular or longitudinal in extent, exist as individual and composite landforms, show prominent topographic depressions or can entirely be filled with water or sediment. For these reasons, attributes like circularity, size, drainage area and topology of landform elements (e.g. a flat floor surrounded by steep walls) have only a limited potential for automated cirque detection. Here we present a novel, geomorphometric method for automated identification of glacial cirques on digital elevation models that exploits their genetic bowl-like shape. First, we differentiate between glacial and fluvial terrain employing an algorithm based on a moving window approach and multi-scale curvature, which is also capable of fitting the analysis window to valley width. We then fit a plane to the valley stretch clipped by the analysis window and rotate the terrain around the center cell until the plane is level. Doing so, we produce sinks of considerable size if the clipped terrain represents a cirque, while no or only very small sinks develop on other valley stretches. We normalize sink area by window size for sink classification, apply this method to the Sawtooth Mountains, Idaho, and to Fiordland, New Zealand, and compare the results to manually mapped reference cirques. Results indicate that false negatives are produced only in very rugged terrain and false positives occur in rare cases, when valleys are strongly curved in longitudinal direction.

A Mesoscale Model-Based Climatography of Nocturnal Boundary-Layer Characteristics over the Complex Terrain of North-Western Utah.

PubMed

Serafin, Stefano; De Wekker, Stephan F J; Knievel, Jason C

Nocturnal boundary-layer phenomena in regions of complex topography are extremely diverse and respond to a multiplicity of forcing factors, acting primarily at the mesoscale and microscale. The interaction between different physical processes, e.g., drainage promoted by near-surface cooling and ambient flow over topography in a statically stable environment, may give rise to special flow patterns, uncommon over flat terrain. Here we present a climatography of boundary-layer flows, based on a 2-year archive of simulations from a high-resolution operational mesoscale weather modelling system, 4DWX. The geographical context is Dugway Proving Ground, in north-western Utah, USA, target area of the field campaigns of the MATERHORN (Mountain Terrain Atmospheric Modeling and Observations Program) project. The comparison between model fields and available observations in 2012-2014 shows that the 4DWX model system provides a realistic representation of wind speed and direction in the area, at least in an average sense. Regions displaying strong spatial gradients in the field variables, thought to be responsible for enhanced nocturnal mixing, are typically located in transition areas from mountain sidewalls to adjacent plains. A key dynamical process in this respect is the separation of dynamically accelerated downslope flows from the surface.

Influence of Complex Terrain on Wind Fields in the Mojave Desert, Southwestern US

NASA Astrophysics Data System (ADS)

Clow, G. D.; Reynolds, R. L.; Urban, F. E.; Bogle, R.; Vogel, J. M.

2009-12-01

The complex terrain of southern California has important effects on the winds in this dust-producing region. We use the Weather Research and Forecasting Model (WRF) to investigate the influences of rugged topography on the wind field in the Mojave Desert at a variety of scales. For this study, the WRF model was used in a retrospective mode over the time period 2000-to-present, with horizontal resolutions as fine as 1-km in specific areas of interest (i.e., known dust-source areas). At a regional scale, the juxtaposition of California's Central Valley with the Sierra Nevada Mountain Range often generates a band of strong winds extending eastward from the southern end of the Sierra Nevada and Tehachapi Mountains across the Mojave Desert and into Arizona. At finer scales, WRF-derived winds within this band reveal terrain deflection, focusing, channeling, and rapid direction change over short distances. These effects are important for assessing the capacity of wind to produce dust at potential dust-source areas during specific events, and for determining dust-transport pathways. Comparison of the WRF results during strong wind events with data from meteorological stations having dust emission instruments (saltation sensors and/or wind-triggered time-lapse cameras) help elucidate landscape conditions that influence dust emission and patterns of dust transport.

Observations of the evening transition processes on opposing slopes of a north-south oriented mountain

NASA Astrophysics Data System (ADS)

Pardyjak, E.

2014-12-01

The MATERHORN (Mountain Terrain Atmospheric Modeling and Observation) Program is a multiuniversity, multidisciplinary research initiative designed to improve numerical weather prediction in complex terrain and to better understand the physics of complex terrain flow phenomena across a wide range of scales. As part of MATERHORN, field campaigns were conducted at Dugway, UT, USA in Autumn 2012 and Spring 2013. A subset of the campaigns included dense observations along the East Slope of Granite Peak (40.096° N, -113.253° W), as well as additional observations on the opposing west facing slope. East Slope observations included five multi-sonic anemometer eddy covariance towers (two with full energy budget stations), eleven small energy budget stations, fifteen automated weather stations, a distributed temperature sensing (DTS) system, hot-film anemometry, infrared camera surface temperature observations and up to three Doppler lidars. West Slope operations were less intense with three main towers, two of which included sonic anemometry and one, which included full surface energy balance observations. For this presentation, our analysis will focus on characterizing and contrasting the response of mean wind circulations and thermodynamics variables, as well as turbulence quantities during the evening transitions on both the East Slope and West Slope when solar irradiation differences of the slope surfaces is extremely large.

Monitoring of snowpack dynamics in mountainous terrain by cosmic-ray neutron sensing compared to Terrestrial Laser Scanning observations

NASA Astrophysics Data System (ADS)

Schattan, P.; Baroni, G.; Schrön, M.; Köhli, M.; Oswald, S. E.; Huttenlau, M.; Achleitner, S.

2017-12-01

Monitoring a mountain snowpack in a representative domain of several hectares is challenging due to its high heterogeneity in time and space. Recent studies have suggested cosmic-ray neutron sensing (CRNS) as a promising method for monitoring snow representatively at these scales. Little is known however about the depth of sensitivity, the effects of fractional snow coverage in complex terrain or the influence of snow density profiles. Therefore, a field campaign in the Austrian Alps was conducted from March 2014 to June 2016. The main scope was to evaluate the characteristics of CRNS for monitoring a snowpack in a relatively wet and mountainous environment. During the experiment, the study site experienced a peak snow accumulation in terms of snow water equivalent (SWE) of up to 600 mm in the 2014/2015 winter season. Snow depth (SD) and SWE measurements from an automatic weather station were compared to CRNS neutron counts. Several spatially distributed Terrestrial Laser Scanning (TLS)-based SD and SWE maps were additionally used to cope with the spatial heterogeneity of the site. Furthermore, an URANOS neutron transport model was set up to provide additional insights into the response of CRNS to the presence of a complex snowpack. Therein, spatially distributed SWE scenarios and different snow density assumptions are used for hypothesis testing. The field measurements revealed an unexpectedly high potential of CRNS for monitoring heterogeneous snowpack dynamics beyond shallow snowpacks. A clear, nonlinear relation was found for both SD and SWE with neutron counts. In contrast to previous studies suggesting signal saturation at around 100 mm of SWE, complete signal saturation was observed only for SWE values beyond 500 to 600 mm. In addition, first modelling results highlight the effects of snow density profiles, small-scale changes in SWE, and the complex patterns of fractional snow cover on neutron counts. Understanding the interactions between neutrons and snow cover in complex terrain potentially improves the transferability of the results to other locations.

Shifts in wind energy potential following land-use driven vegetation dynamics in complex terrain.

PubMed

Fang, Jiannong; Peringer, Alexander; Stupariu, Mihai-Sorin; Pǎtru-Stupariu, Ileana; Buttler, Alexandre; Golay, Francois; Porté-Agel, Fernando

2018-10-15

Many mountainous regions with high wind energy potential are characterized by multi-scale variabilities of vegetation in both spatial and time dimensions, which strongly affect the spatial distribution of wind resource and its time evolution. To this end, we developed a coupled interdisciplinary modeling framework capable of assessing the shifts in wind energy potential following land-use driven vegetation dynamics in complex mountain terrain. It was applied to a case study area in the Romanian Carpathians. The results show that the overall shifts in wind energy potential following the changes of vegetation pattern due to different land-use policies can be dramatic. This suggests that the planning of wind energy project should be integrated with the land-use planning at a specific site to ensure that the expected energy production of the planned wind farm can be reached over its entire lifetime. Moreover, the changes in the spatial distribution of wind and turbulence under different scenarios of land-use are complex, and they must be taken into account in the micro-siting of wind turbines to maximize wind energy production and minimize fatigue loads (and associated maintenance costs). The proposed new modeling framework offers, for the first time, a powerful tool for assessing long-term variability in local wind energy potential that emerges from land-use change driven vegetation dynamics over complex terrain. Following a previously unexplored pathway of cause-effect relationships, it demonstrates a new linkage of agro- and forest policies in landscape development with an ultimate trade-off between renewable energy production and biodiversity targets. Moreover, it can be extended to study the potential effects of micro-climatic changes associated with wind farms on vegetation development (growth and patterning), which could in turn have a long-term feedback effect on wind resource distribution in mountainous regions. Copyright © 2018 Elsevier B.V. All rights reserved.

The Convective and Orographically Induced Precipitation Study (COPS): The Scientific Strategy, the Field Phase, and Research Highlights

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wulfmeyer, Volker; Behrendt, Andreas; Kottmeir, Christoph

2011-02-24

Within the frame of the international field campaign COPS (Convective and Orographically-induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. The COPS field phase was performed from 01 June - 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges Mountains, the Rhine valley and the Black Forest Mountains. The collected data set covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase up to their decay. 18 Intensive Operation Periods (IOPs) with 34 operation days andmore » 8 additional Special Observation Periods (SOPs) were performed providing a comprehensive data set covering different forcing conditions. In this paper an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Some highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS provided new insight in key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of QPF by the assimilation of new observations, and in the performance of ensembles of convection permitting models in complex terrain.« less

Performance and evaluation of a coupled prognostic model TAPM over a mountainous complex terrain industrial area

NASA Astrophysics Data System (ADS)

Matthaios, Vasileios N.; Triantafyllou, Athanasios G.; Albanis, Triantafyllos A.; Sakkas, Vasileios; Garas, Stelios

2018-05-01

Atmospheric modeling is considered an important tool with several applications such as prediction of air pollution levels, air quality management, and environmental impact assessment studies. Therefore, evaluation studies must be continuously made, in order to improve the accuracy and the approaches of the air quality models. In the present work, an attempt is made to examine the air pollution model (TAPM) efficiency in simulating the surface meteorology, as well as the SO2 concentrations in a mountainous complex terrain industrial area. Three configurations under different circumstances, firstly with default datasets, secondly with data assimilation, and thirdly with updated land use, ran in order to investigate the surface meteorology for a 3-year period (2009-2011) and one configuration applied to predict SO2 concentration levels for the year of 2011.The modeled hourly averaged meteorological and SO2 concentration values were statistically compared with those from five monitoring stations across the domain to evaluate the model's performance. Statistical measures showed that the surface temperature and relative humidity are predicted well in all three simulations, with index of agreement (IOA) higher than 0.94 and 0.70 correspondingly, in all monitoring sites, while an overprediction of extreme low temperature values is noted, with mountain altitudes to have an important role. However, the results also showed that the model's performance is related to the configuration regarding the wind. TAPM default dataset predicted better the wind variables in the center of the simulation than in the boundaries, while improvement in the boundary horizontal winds implied the performance of TAPM with updated land use. TAPM assimilation predicted the wind variables fairly good in the whole domain with IOA higher than 0.83 for the wind speed and higher than 0.85 for the horizontal wind components. Finally, the SO2 concentrations were assessed by the model with IOA varied from 0.37 to 0.57, mostly dependent on the grid/monitoring station of the simulated domain. The present study can be used, with relevant adaptations, as a user guideline for future conducting simulations in mountainous complex terrain.

Simulation of tracer dispersion from elevated and surface releases in complex terrain

NASA Astrophysics Data System (ADS)

Hernández, J. F.; Cremades, L.; Baldasano, J. M.

A new version of an advanced mesoscale dispersion modeling system for simulating passive air pollutant dispersion in the real atmospheric planetary boundary layer (PBL), is presented. The system comprises a diagnostic mass-consistent meteorological model and a Lagrangian particle dispersion model (LADISMO). The former version of LADISMO, developed according to Zannetti (Air pollution modelling, 1990), was based on the Monte Carlo technique and included calculation of higher-order moments of vertical random forcing for convective conditions. Its ability to simulate complex flow dispersion has been stated in a previous paper (Hernández et al. 1995, Atmospheric Environment, 29A, 1331-1341). The new version follows Thomson's scheme (1984, Q. Jl Roy. Met. Soc.110, 1107-1120). It is also based on Langevin equation and follows the ideas given by Brusasca et al. (1992, Atmospheric Environment26A, 707-723) and Anfossi et al. (1992, Nuovo Cemento 15c, 139-158). The model is used to simulate the dispersion and predict the ground level concentration (g.l.c.) of a tracer (SF 6) released from both an elevated source ( case a) and a ground level source ( case b) in a highly complex mountainous terrain during neutral and synoptically dominated conditions ( case a) and light and apparently stable conditions ( case b). The last case is considered as being a specially difficult task to simulate. In fact, few works have reported situations with valley drainage flows in complex terrains and real stable atmospheric conditions with weak winds. The model assumes that nearly calm situations associated to strong stability and air stagnation, make the lowest layers of PBL poorly diffusive (Brusasca et al., 1992, Atmospheric Environment26A, 707-723). Model results are verified against experimental data from Guardo-90 tracer experiments, an intensive field campaign conducted in the Carrion river valley (Northern Spain) to study atmospheric diffusion within a steep walled valley in mountainous terrain (Ibarra, 1992, Energia, No. 1, 74-85).

Topographical effects of climate dataset and their impacts on the estimation of regional net primary productivity

NASA Astrophysics Data System (ADS)

Sun, L. Qing; Feng, Feng X.

2014-11-01

In this study, we first built and compared two different climate datasets for Wuling mountainous area in 2010, one of which considered topographical effects during the ANUSPLIN interpolation was referred as terrain-based climate dataset, while the other one did not was called ordinary climate dataset. Then, we quantified the topographical effects of climatic inputs on NPP estimation by inputting two different climate datasets to the same ecosystem model, the Boreal Ecosystem Productivity Simulator (BEPS), to evaluate the importance of considering relief when estimating NPP. Finally, we found the primary contributing variables to the topographical effects through a series of experiments given an overall accuracy of the model output for NPP. The results showed that: (1) The terrain-based climate dataset presented more reliable topographic information and had closer agreements with the station dataset than the ordinary climate dataset at successive time series of 365 days in terms of the daily mean values. (2) On average, ordinary climate dataset underestimated NPP by 12.5% compared with terrain-based climate dataset over the whole study area. (3) The primary climate variables contributing to the topographical effects of climatic inputs for Wuling mountainous area were temperatures, which suggest that it is necessary to correct temperature differences for estimating NPP accurately in such a complex terrain.

A Preliminary Study of Aroma Composition and Impact Odorants of Cabernet Franc Wines under Different Terrain Conditions of the Loess Plateau Region (China).

PubMed

Jiang, Bao; Zhang, Zhen-Wen

2018-05-05

Due to its appropriate climate characteristics, the Loess Plateau region is considered to be one of the biggest optimal regions for producing high-quality mountain wine in China. However, the complex landform conditions of vineyards are conducive to the formation of mountainous microclimates, which ultimately influence the wine quality. This study aimed to elucidate the influences of three terrain conditions of the Loess Plateau region on the aroma compounds of Cabernet Franc wines by using solid phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). A total of 40, 36 and 35 volatiles were identified and quantified from the flat, lower slope and higher slope vineyards, respectively. Esters were the largest group of volatiles, accounting for 54.6⁻56.6% of total volatiles, followed by alcohols. Wines from the slope lands had the higher levels of aroma compounds than that from flat land. According to their aroma-active values (OAVs), ethyl hexanoate, ethyl octanoate and isoamyl acetate were the most powerful compounds among the eight impact odorants, showing only quantitative but not qualitative differences between the three terrain wines. The shapes of the OAVs for three terrain wines were very similar.

Cold air drainage flows subsidize montane valley ecosystem productivity

Treesearch

Kimberly A. Novick; Andrew C. Oishi; Chelcy Ford Miniat

2016-01-01

In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate...

Adjustment of relative humidity and temperature for differences in elevation.

Treesearch

Owen P. Cramer

1961-01-01

The variation of fire-weather elements in mountainous terrain is complex at any one time, and the patterns vary considerably with time. During periods of serious fire weather, this variation becomes important. Much information is obtainable by local interpretation of available forecasts and observations. Optimum use of available information requires some understanding...

Measurements of thermal updraft intensity over complex terrain using American white pelicans and a simple boundary-layer forecast model

USGS Publications Warehouse

Shannon, H.D.; Young, G.S.; Yates, M.; Fuller, Mark R.; Seegar, W.

2003-01-01

An examination of boundary-layer meteorological and avian aerodynamic theories suggests that soaring birds can be used to measure the magnitude of vertical air motions within the boundary layer. These theories are applied to obtain mixed-layer normalized thermal updraft intensity over both flat and complex terrain from the climb rates of soaring American white pelicans and from diagnostic boundary-layer model-produced estimates of the boundary-layer depth zi and the convective velocity scale w*. Comparison of the flatland data with the profiles of normalized updraft velocity obtained from previous studies reveals that the pelican-derived measurements of thermal updraft intensity are in close agreement with those obtained using traditional research aircraft and large eddy simulation (LES) in the height range of 0.2 to 0.8 zi. Given the success of this method, the profiles of thermal vertical velocity over the flatland and the nearby mountains are compared. This comparison shows that these profiles are statistically indistinguishable over this height range, indicating that the profile for thermal updraft intensity varies little over this sample of complex terrain. These observations support the findings of a recent LES study that explored the turbulent structure of the boundary layer using a range of terrain specifications. For terrain similar in scale to that encountered in this study, results of the LES suggest that the terrain caused less than an 11% variation in the standard deviation of vertical velocity.

A multiscale and multidisciplinary investigation of ecosystem-atmosphere CO2 exchange over the rocky mountains of colorado

USGS Publications Warehouse

Sun, Jielun; Oncley, S.P.; Burns, Sean P.; Stephens, B.B.; Lenschow, D.H.; Campos, T.; Monson, Russell K.; Schimel, D.S.; Sacks, W.J.; De Wekker, S. F. J.; Lai, C.-T.; Lamb, B.; Ojima, D.; Ellsworth, P.Z.; Sternberg, L.S.L.; Zhong, S.; Clements, C.; Moore, D.J.P.; Anderson, D.E.; Watt, A.S.; Hu, Jiawen; Tschudi, M.; Aulenbach, S.; Allwine, E.; Coons, T.

2010-01-01

A field study combined with modeling investigation demonstrated that the organization of CO2 transport by mountain terrain strongly affects the regional CO2 budget. Atmospheric dynamics can lead to complicated flows generated by inhomogeneous landscapes, topography or synoptic weather systems. The field campaign conducted of a ground deployment, the Carbon in the Mountain Experiment (CME04), and an aircraft deployment of the national Center for Atmospheric Research (NCAR) C-130, the Airborne Carbon in the Mountains Experiment (ACME04) over the period of spring to fall of 2004 to cover the seasonal variation of ecosystem-atmosphere carbon exchange. The role of the mountain circulation in CO2 transport can be played over seemingly flat terrain by mesoscale flows generated by various physical processes. The three dimensional observation strategy considered can also be applied over flat terrain.

An Integrated Processing Strategy for Mountain Glacier Motion Monitoring Based on SAR Images

NASA Astrophysics Data System (ADS)

Ruan, Z.; Yan, S.; Liu, G.; LV, M.

2017-12-01

Mountain glacier dynamic variables are important parameters in studies of environment and climate change in High Mountain Asia. Due to the increasing events of abnormal glacier-related hazards, research of monitoring glacier movements has attracted more interest during these years. Glacier velocities are sensitive and changing fast under complex conditions of high mountain regions, which implies that analysis of glacier dynamic changes requires comprehensive and frequent observations with relatively high accuracy. Synthetic aperture radar (SAR) has been successfully exploited to detect glacier motion in a number of previous studies, usually with pixel-tracking and interferometry methods. However, the traditional algorithms applied to mountain glacier regions are constrained by the complex terrain and diverse glacial motion types. Interferometry techniques are prone to fail in mountain glaciers because of their narrow size and the steep terrain, while pixel-tracking algorithm, which is more robust in high mountain areas, is subject to accuracy loss. In order to derive glacier velocities continually and efficiently, we propose a modified strategy to exploit SAR data information for mountain glaciers. In our approach, we integrate a set of algorithms for compensating non-glacial-motion-related signals which exist in the offset values retrieved by sub-pixel cross-correlation of SAR image pairs. We exploit modified elastic deformation model to remove the offsets associated with orbit and sensor attitude, and for the topographic residual offset we utilize a set of operations including DEM-assisted compensation algorithm and wavelet-based algorithm. At the last step of the flow, an integrated algorithm combining phase and intensity information of SAR images will be used to improve regional motion results failed in cross-correlation related processing. The proposed strategy is applied to the West Kunlun Mountain and Muztagh Ata region in western China using ALOS/PALSAR data. The results show that the strategy can effectively improve the accuracy of velocity estimation by reducing the mean and standard deviation values from 0.32 m and 0.4 m to 0.16 m. It is proved to be highly appropriate for monitoring glacier motion over a widely varying range of ice velocities with a relatively high accuracy.

An archean suture zone in the Tobacco Root Mountains? (1984) Evolution of Archean Continental Crust, SW Montana (1985)

NASA Technical Reports Server (NTRS)

Mogk, D. W.; Kain, L.

1985-01-01

The Lake Plateau area of the Beartooth Mountains, Montana were mapped and geochemically sampled. The allochthonous nature of the Stillwater Complex was interpreted as a Cordilleran-style continental margin. The metamorphic and tectonic history of the Beartooth Mountains was addressed. The Archean geology of the Spanish Peaks area, northern Madison Range was addressed. A voluminous granulite terrain of supracrustal origin was identified, as well as a heretofore unknown Archean batholithic complex. Mapping, petrologic, and geochemical investigations of the Blacktail Mountains, on the western margin of the Wyoming Province, are completed. Mapping at a scale of 1:24000 in the Archean rocks of the Gravelly Range is near completion. This sequence is dominantly of stable-platform origin. Samples were collected for geothermometric/barometric analysis and for U-Pb zircon age dating. The analyses provide the basis for additional geochemical and geochronologic studies. A model for the tectonic and geochemical evolution of the Archean basement of SW Montana is presented.

Mountain Biking: Does Rough Terrain Make Rugged Riders?

ERIC Educational Resources Information Center

Cinque, Chris

1987-01-01

No formal research has been conducted on the training effects and injury risks of all-terrain bicycles in mountain biking, but experience indicates they are apparently safe and may provide greater fitness benefits than traditional bicycles. The bicycles are described, and their apparent benefits are discussed. (MT)

Horizontal heat fluxes over complex terrain computed using a simple mixed-layer model and a numerical model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, Fujio; Kuwagata, Tuneo

1995-02-01

The thermally induced local circulation over a periodic valley is simulated by a two-dimensional numerical model that does-not include condensational processes. During the daytime of a clear, calm day, heat is transported from the mountainous region to the valley area by anabatic wind and its return flow. The specific humidity is, however, transported in an inverse manner. The horizontal exchange rate of sensible heat has a horizontal scale similarity, as long as the horizontal scale is less than a critical width of about 100 km. The sensible heat accumulated in an atmospheric column over an arbitrary point can be estimatedmore » by a simple model termed the uniform mixed-layer model (UML). The model assumes that the potential temperature is both vertically and horizontally uniform in the mixed layer, even over the complex terrain. The UML model is valid only when the horizontal scale of the topography is less than the critical width and the maximum difference in the elevation of the topography is less than about 1500 m. Latent heat is accumulated over the mountainous region while the atmosphere becomes dry over the valley area. When the horizontal scale is close to the critical width, the largest amount of humidity is accumulated during the late afternoon over the mountainous region. 18 refs., 15 figs., 1 tab.« less

Effects of complex terrain on atmospheric flow: dividing streamline observations and quantification

NASA Astrophysics Data System (ADS)

Thompson, Michael; Fernando, Harindra; di Sabatino, Silvana; Leo, Laura; University of Notre Dame Team

2013-11-01

As part of the MATERHORN field campaign on atmospheric flow in mountainous terrain, the dividing streamline concept for stratified flow over obstacles was investigated using smoke flow visualization and meteorological measurements. At small Froude numbers (Fr < 1), a stratified flow approaching a mountain either possesses enough kinetic energy to pass over the summit or else flow around the sides, with dividing streamlines separating the two scenarios. An isolated northwestern peak of the Granite Mountain, approximately 60 m in height, was used for the study. Incoming flow velocities and temperature profiles were measured upstream using sonic anemometers and thermocouples mounted on a 32 m tower, while onsite measurements were taken with portable weather stations. Sufficiently strong stratification was developed around 3:00AM GMT, with Froude numbers in the range for dividing streamlines to exist. In the first trial, suitably placed red smoke releases were used and in another trial white smoke was released from a 25 m crane. In both cases well-defined dividing streamlines were observed and its vertical location was at a height about half of the mountain height, which is consistent with theoretical results based on Shepard's formula. This research was supported by the Office of Naval Research (ONR) grant number N00014-11-1-0709.

Using High Resolution Remotely Sensed Data to Predict Territory Occupancy and Mircrorefugia for a Habitat Specialist, the American Pika (Ochotona princeps)

NASA Astrophysics Data System (ADS)

Beers, A.; Ray, C.

2015-12-01

Climate change is likely to affect mountainous areas unevenly due to the complex interactions between topography, vegetation, and the accumulation of snow and ice. This heterogeneity will complicate relationships between species presence and large-scale drivers such as precipitation and make predicting habitat extent and connectivity much more difficult. We studied the potential for fine-scale variation in climate and habitat use throughout the year in the American pika (Ochotona princeps), a talus specialist of mountainous western North America known for strong microhabitat affiliation. Not all areas of talus are likely to be equally hospitable, which may reduce connectivity more than predicted by large-scale occupancy drivers. We used high resolution remotely sensed data to create metrics of the terrain and land cover in the Niwot Ridge (NWT) LTER site in Colorado. We hypothesized that pikas preferentially use heterogeneous terrain, as it might foster greater snow accumulation, and used radio telemetry to test this with radio-collared pikas. Pikas use heterogeneous terrain during snow covered periods and less heterogeneous area during the summer. This suggests that not all areas of talus habitat are equally suitable as shelter from extreme conditions but that pikas need more than just shelter from winter cold. With those results we created a predictive map using the same habitat metrics to model the extent of suitable habitat across the NWT area. These strong effects of terrain on pika habitat use and territory occupancy show the great utility that high resolution remotely sensed data can have in ecological applications. With increasing effects of climate change in mountainous regions, this modeling approach is crucial for quantifying habitat connectivity at both small and large scales and to identify potential refugia for threatened or isolated species.

Airflows and turbulent flux measurements in mountainous terrain: Part 1. Canopy and local effects

USGS Publications Warehouse

Turnipseed, Andrew A.; Anderson, Dean E.; Blanken, Peter D.; Baugh, William M.; Monson, Russell K.

2003-01-01

We have studied the effects of local topography and canopy structure on turbulent flux measurements at a site located in mountainous terrain within a subalpine, coniferous forest. Our primary aim was to determine whether the complex terrain of the site affects the accuracy of eddy flux measurements from a practical perspective. We observed displacement heights, roughness lengths, spectral peaks, turbulent length scales, and profiles of turbulent intensities that were comparable in magnitude and pattern to those reported for forest canopies in simpler terrain. We conclude that in many of these statistical measures, the local canopy exerts considerably more influence than does topographical complexity. Lack of vertical flux divergence and modeling suggests that the flux footprints for the site are within the standards acceptable for the application of flux statistics. We investigated three different methods of coordinate rotation: double rotation (DR), triple rotation (TR), and planar-fit rotation (PF). Significant variability in rotation angles at low wind speeds was encountered with the commonly used DR and TR methods, as opposed to the PF method, causing some overestimation of the fluxes. However, these differences in fluxes were small when applied to large datasets involving sensible heat and CO2 fluxes. We observed evidence of frequent drainage flows near the ground during stable, stratified conditions at night. Concurrent with the appearance of these flows, we observed a positive bias in the mean vertical wind speed, presumably due to subtle topographic variations inducing a flow convergence below the measurement sensors. In the presence of such drainage flows, advection of scalars and non-zero bias in the mean vertical wind speed can complicate closure of the mass conservation budget at the site.

Upper-level enhancement of microphysical processes in extratropical cyclones observed during OLYMPEX

NASA Astrophysics Data System (ADS)

Rowe, A.; McMurdie, L. A.; Houze, R.; Zagrodnik, J. P.; Schuldt, T.; Chaplin, M.

2017-12-01

Data collected during the Olympic Mountains Experiment (OLYMPEX) of fall 2015-winter 2016 offer a unique opportunity to document enhancement of precipitation on the windward side of a mountain range as mid-latitude cyclones encountered the complex terrain of the Olympic Mountains. During the campaign, extensive instrumentation was deployed, including ground-based dual-polarization Doppler radars on the windward and leeward sides of the mountains and research aircraft providing in situ microphysical measurements and triple-frequency radar data over the ground-based sites and highest elevations. These datasets provide unprecedented detail on microphysical and dynamical processes associated with precipitation enhancement. Previous studies of precipitation enhancement over mountains have focused on surface rainfall amounts. However, the airflow over the terrain affects precipitation throughout the vertical columns of the atmosphere passing over the mountains. The OLYMPEX data were collected in a way that allows the mechanisms leading to enhancement to be examined at all levels. In particular, NASA's S-band and the NSF/CSWR DOW6 X-band dual-polarization radars provided high-resolution vertical cross sections in sectors upwind and over the mountains. The degree of upper-level enhancement seen in these radar data was most pronounced when the integrated vapor transport was strong, stability was moist neutral, and melting levels were relatively high. These conditions were often found within the warm sectors of the mid-latitude cyclones observed in OLYMPEX. Within widespread stratiform echo, radar data revealed layers of enhanced differential reflectivity aloft in addition to the enhanced reflectivity. In situ microphysical probe data from the University of North Dakota Citation aircraft were obtained in the context of these ground-based radar observations, which along with observations from the APR3 radar aboard the DC8 research aircraft, provide a unique dataset for investigating these ice-based microphysical processes aloft, including over the high terrain. Insights from these coincident datasets include the role of generating cells in production of supercooled liquid water and riming aloft within the warm sector during a heavy rain event.

Geomorphological Mapping of Sputnik Planum and Surrounding Terrain on Pluto

NASA Astrophysics Data System (ADS)

White, O. L.; Stern, S. A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.; Young, L. A.; Moore, J. M.; Cheng, A. F.

2015-12-01

The New Horizons flyby of Pluto in July 2015 has provided the first few close-up images of the Kuiper belt object, which reveal it to have a highly diverse range of terrains, implying a complex geological history. The highest resolution images that have yet been returned are seven lossy 400 m/pixel frames that cover the majority of the prominent Plutonian feature informally named Sputnik Planum (all feature names are currently informal), and its surroundings. This resolution is sufficient to allow detailed geomorphological mapping of this area to commence. Lossless versions of all 15 frames that make up the mosaic will be returned in September 2015, and the map presented at AGU will incorporate the total area covered by these frames. Sputnik Planum, with an area of ~650,000 km2, is notable for its smooth appearance and apparent total lack of impact craters at 400 m/pixel resolution. The Planum actually displays a wide variety of textures across its expanse, which includes smooth and pitted plains to the south, polygonal terrain at its center (the polygons can reach tens of kilometers in size and are bounded by troughs that sometimes feature central ridges), and, to the north, darker polygonal terrain displaying patterns indicative of glacial flow. Within these plains there exist several well-defined outcrops of a mottled, light/dark unit that reach from several to tens of kilometers across. Separating Sputnik Planum from the dark, cratered equatorial terrain of Cthulhu Regio on its south-western margin is a unit of chaotically arranged mountains; similar mountainous units exist on the south and western margins. The northern margin is bounded by rugged, hilly, cratered terrain into which ice of Sputnik Planum appears to be intruding in places. Terrain of similar relief exists to the east, but is much brighter than that to the north. The southernmost extent of the mosaic features a unit of rough, undulating terrain that displays very few impact craters at 400 m/pixel resolution.

Automated algorithm for mapping regions of cold-air pooling in complex terrain

NASA Astrophysics Data System (ADS)

Lundquist, Jessica D.; Pepin, Nicholas; Rochford, Caitlin

2008-11-01

In complex terrain, air in contact with the ground becomes cooled from radiative energy loss on a calm clear night and, being denser than the free atmosphere at the same elevation, sinks to valley bottoms. Cold-air pooling (CAP) occurs where this cooled air collects on the landscape. This article focuses on identifying locations on a landscape subject to considerably lower minimum temperatures than the regional average during conditions of clear skies and weak synoptic-scale winds, providing a simple automated method to map locations where cold air is likely to pool. Digital elevation models of regions of complex terrain were used to derive surfaces of local slope, curvature, and percentile elevation relative to surrounding terrain. Each pixel was classified as prone to CAP, not prone to CAP, or exhibiting no signal, based on the criterion that CAP occurs in regions with flat slopes in local depressions or valleys (negative curvature and low percentile). Along-valley changes in the topographic amplification factor (TAF) were then calculated to determine whether the cold air in the valley was likely to drain or pool. Results were checked against distributed temperature measurements in Loch Vale, Rocky Mountain National Park, Colorado; in the Eastern Pyrenees, France; and in Yosemite National Park, Sierra Nevada, California. Using CAP classification to interpolate temperatures across complex terrain resulted in improvements in root-mean-square errors compared to more basic interpolation techniques at most sites within the three areas examined, with average error reductions of up to 3°C at individual sites and about 1°C averaged over all sites in the study areas.

Short-term Wind Forecasting at Wind Farms using WRF-LES and Actuator Disk Model

NASA Astrophysics Data System (ADS)

Kirkil, Gokhan

2017-04-01

Short-term wind forecasts are obtained for a wind farm on a mountainous terrain using WRF-LES. Multi-scale simulations are also performed using different PBL parameterizations. Turbines are parameterized using Actuator Disc Model. LES models improved the forecasts. Statistical error analysis is performed and ramp events are analyzed. Complex topography of the study area affects model performance, especially the accuracy of wind forecasts were poor for cross valley-mountain flows. By means of LES, we gain new knowledge about the sources of spatial and temporal variability of wind fluctuations such as the configuration of wind turbines.

Orographic Impacts on Liquid and Ice-Phase Precipitation Processes during OLYMPEX

NASA Astrophysics Data System (ADS)

Petersen, W. A.; Hunzinger, A.; Gatlin, P. N.; Wolff, D. B.

2017-12-01

The Global Precipitation Measurement (GPM) mission Olympic Mountains Experiment (OLYMPEX) focused on physical validation of GPM products in cold-season, mid-latitude frontal precipitation occurring over the Olympic Mountains of Washington State. Herein, we use data collected by the NASA S-band polarimetric radar (NPOL) to quantify and examine ice (IWP), liquid (LWP) and total water paths (TWP) relative to surface precipitation rates and column hydrometeor types for several cases occurring in different synoptic and/or Froude number regimes. These quantities are compared to coincident precipitation properties measured or estimated by GPM's Microwave Imager (GMI) and Dual-frequency Precipitation Radar (DPR). Because ice scattering is the dominant radiometric signature used by the GMI for estimating precipitation over land, and because the DPR is greatly affected by ground clutter in the lowest 1 - 2 km above ground, measurement limitations combined with orographic forcing may impact the degree to which DPR and/or GMI algorithms are able to adequately observe and estimate precipitation over and around orography.Preliminary case results suggest: 1) as expected, the Olympic Mountains force robust enhancements in the liquid and ice microphysical processes on windward slopes, especially in atmospheric river events; 2) localized orographic enhancements alter the balance of liquid and frozen precipitation contributions (IWP/TWP, LWP/TWP) to near surface rain rate, and for two cases examined thus far the balance seems to be sensitive to flow direction at specific intersections with the terrain orientation; and 3) GPM measurement limitations related to the depth of surface clutter impact for the DPR, and degree to which ice processes are coupled to the orographic rainfall process (DPR and GMI), especially along windward mountain slopes, may constrain the ability of retrieval algorithms to properly estimate near-surface precipitation quantities over complex terrain. Ongoing analysis of the OLMPEX dataset will better isolate controls on the orographic precipitation process, better define uncertainties in GPM measurements, and contribute to physically-based approaches for mitigating errors in estimation due to measurement and/or algorithm limitations over complex terrain.

Landscape structure control on soil CO2 efflux variability in complex terrain: Scaling from point observations to watershed scale fluxes

Treesearch

Diego A. Riveros-Iregui; Brian L. McGlynn

2009-01-01

We investigated the spatial and temporal variability of soil CO2 efflux across 62 sites of a 393-ha complex watershed of the northern Rocky Mountains. Growing season (83 day) cumulative soil CO2 efflux varied from ~300 to ~2000 g CO2 m-2, depending upon landscape position, with a median of 879.8 g CO2 m-2. Our findings revealed that highest soil CO2 efflux rates were...

Spatial Investigation of Columnar AOD and Near-Surface PM2.5 Concentrations During the 2013 American and Yosemite Rim Fires

NASA Astrophysics Data System (ADS)

Loria Salazar, S. M.; Holmes, H.; Arnott, W. P.; Moosmuller, H.; Liming, A.; Echevarria, B.

2014-12-01

The study of aerosol pollution transport and optical properties in the western U.S. is a challenge due to the complex terrain, bright surfaces, presence of anthropogenic and biogenic emissions, secondary organic aerosol formation, and smoke from wild fires. In addition, the complex terrain influences transport phenomena by recirculating mountain air from California to Nevada, where air pollution from the Sierra Nevada Mountains (SNM) is mixed with urban air from the Central Valley in California. Previous studies in Reno hypothesize that elevated aerosol concentrations aloft, above the convective boundary layer height, make air quality monitoring in Reno challenging with MODIS products. Here, we analyze data from August 2013 as a case study for wildfire smoke plumes in California and Nevada. During this time period, northern California was impacted by large wild fires known as the American and Yosemite Rim fires. Thousands of acres burned, generating large quantities of aerosol pollutants that were transported downwind. The aim of the present work is to investigate the fire plume behavior and transport phenomena using ground level PM2.5 concentrations from routine monitoring networks and aerosol optical properties from AERONET, both at multiple locations in California and Nevada. In addition, the accuracy of MODIS (Collection 6) and VIIRS aerosol satellite products will be evaluated. The multispectral photoacoustic instruments and reciprocal nephelometers located in Reno support the estimation of approximated aerosol height. The objectives are to investigate the impact of the vertical distribution of PM concentrations on satellite aerosol optical depth (AOD) retrievals; assess the ability to estimate ground level PM2.5 mass concentrations for wildfire smoke plumes from satellite remote sensing; and investigate the influence of complex terrain on the transport of pollutants, convective boundary layer depth, and aerosol optical height.

Terrain and landform influence on Tsuga canadensis (L.) Carriere (Eastern Hemlock) distribution in the southern Appalachian Mountains

Treesearch

G. Narayanaraj; P.V. Bolstad; K.J. Elliott; J.M. Vose

2010-01-01

We examined the relationships between hemlock distribution and abundance and terrain attributes for the Coweeta Basin in the southern Appalachian Mountains. Field measurements were combined with GIS mapping methods to develop predictive models of abundance and distribution of Tsuga canadensis (L.) Carriere (eastern hemlock) and evaluate the co-...

Rates and causes of accidents for general aviation aircraft operating in a mountainous and high elevation terrain environment.

PubMed

Aguiar, Marisa; Stolzer, Alan; Boyd, Douglas D

2017-10-01

Flying over mountainous and/or high elevation terrain is challenging due to rapidly changeable visibility, gusty/rotor winds and downdrafts and the necessity of terrain avoidance. Herein, general aviation accident rates and mishap cause/factors were determined (2001-2014) for a geographical region characterized by such terrain. Accidents in single piston engine-powered aircraft for states west of the US continental divide characterized by mountainous terrain and/or high elevation (MEHET) were identified from the NTSB database. MEHET-related-mishaps were defined as satisfying any one, or more, criteria (controlled flight into terrain/obstacles (CFIT), downdrafts, mountain obscuration, wind-shear, gusting winds, whiteout, instrument meteorological conditions; density altitude, dust-devil) cited as factors/causal in the NTSB report. Statistics employed Poisson distribution and contingency tables. Although the MEHET-related accident rate declined (p<0.001) 57% across the study period, the high proportion of fatal accidents showed little (40-43%) diminution (χ 2 =0.935). CFIT and wind gusts/shear were the most frequent accident cause/factor categories. For CFIT accidents, half occurred in degraded visibility with only 9% operating under instrument flight rules (IFR) and the majority (85%) involving non-turbo-charged engine-powered aircraft. For wind-gust/shear-related accidents, 44% occurred with a cross-wind exceeding the maximum demonstrated aircraft component. Accidents which should have been survivable but which nevertheless resulted in a fatal outcome were characterized by poor accessibility (60%) and shoulder harness under-utilization (41%). Despite a declining MEHET-related accident rate, these mishaps still carry an elevated risk of a fatal outcome. Airmen should be encouraged to operate in this environment utilizing turbo-charged-powered airplanes and flying under IFR to assure terrain clearance. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Investigation of Topography Modulated Low Level Moisture Convergence Patterns in the Southern Appalachians Using WRF

NASA Astrophysics Data System (ADS)

Wilson, A. M.; Duan, Y.; Barros, A.

2015-12-01

The Southern Appalachian Mountains (SAM) region is a biodiversity hot-spot that is vulnerable to land use/land cover changes due to its proximity to the rapidly growing population in the Southeast U.S. Persistent near surface moisture and associated microclimates observed in this region have been documented since the colonization of the area. The landform in this area, in particular in the inner mountain region, is highly complex with nested valleys and ridges. The geometry of the terrain causes distinct diurnal and seasonal local flow patterns that result in highly complex interactions of this low level moisture with meso- and synoptic-scale cyclones passing through the region. The Weather Research and Forecasting model (WRF) was used to conduct high resolution simulations of several case studies of warm season precipitation in the SAM with different synoptic-scale conditions to investigate this interaction between local and larger-scale flow patterns. The aim is to elucidate the microphysical interactions among these shallow orographic clouds and preexisting precipitating cloud systems and identify uncertainties in the model microphysics using in situ measurements. Findings show that ridge-valley precipitation gradients, in particular the "reverse" to the classical orographic effect observed in inner mountain valleys, is linked to horizontal heterogeneity in the vertical structure of low level cloud and precipitation promoted through landform controls on local flow. Moisture convergence patterns follow the peaks and valleys as represented by WRF terrain, and the topography effectively controls their timing and spatial structure. The simulations support the hypothesis that ridge-valley precipitation gradients, and in particular the reverse orographic enhancement effect in inner mountain valleys, is linked to horizontal heterogeneity in the vertical structure of low level clouds and precipitation promoted through landform controls on moisture convergence.

Evaluation of NWP-based Satellite Precipitation Error Correction with Near-Real-Time Model Products and Flood-inducing Storms

NASA Astrophysics Data System (ADS)

Zhang, X.; Anagnostou, E. N.; Schwartz, C. S.

2017-12-01

Satellite precipitation products tend to have significant biases over complex terrain. Our research investigates a statistical approach for satellite precipitation adjustment based solely on numerical weather simulations. This approach has been evaluated in two mid-latitude (Zhang et al. 2013*1, Zhang et al. 2016*2) and three topical mountainous regions by using the WRF model to adjust two high-resolution satellite products i) National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center morphing technique (CMORPH) and ii) Global Satellite Mapping of Precipitation (GSMaP). Results show the adjustment effectively reduces the satellite underestimation of high rain rates, which provides a solid proof-of-concept for continuing research of NWP-based satellite correction. In this study we investigate the feasibility of using NCAR Real-time Ensemble Forecasts*3 for adjusting near-real-time satellite precipitation datasets over complex terrain areas in the Continental United States (CONUS) such as Olympic Peninsula, California coastal mountain ranges, Rocky Mountains and South Appalachians. The research will focus on flood-inducing storms occurred from May 2015 to December 2016 and four satellite precipitation products (CMORPH, GSMaP, PERSIANN-CCS and IMERG). The error correction performance evaluation will be based on comparisons against the gauge-adjusted Stage IV precipitation data. *1 Zhang, Xinxuan, et al. "Using NWP simulations in satellite rainfall estimation of heavy precipitation events over mountainous areas." Journal of Hydrometeorology 14.6 (2013): 1844-1858. *2 Zhang, Xinxuan, et al. "Hydrologic Evaluation of NWP-Adjusted CMORPH Estimates of Hurricane-Induced Precipitation in the Southern Appalachians." Journal of Hydrometeorology 17.4 (2016): 1087-1099. *3 Schwartz, Craig S., et al. "NCAR's experimental real-time convection-allowing ensemble prediction system." Weather and Forecasting 30.6 (2015): 1645-1654.

Mini-Uav LIDAR for Power Line Inspection

NASA Astrophysics Data System (ADS)

Teng, G. E.; Zhou, M.; Li, C. R.; Wu, H. H.; Li, W.; Meng, F. R.; Zhou, C. C.; Ma, L.

2017-09-01

Light detection and ranging (LIDAR) system based on unmanned aerial vehicles (UAVs) recently are in rapid advancement, meanwhile portable and flexible mini-UAV-borne laser scanners have been a hot research field, especially for the complex terrain survey in the mountains and other areas. This study proposes a power line inspection system solution based on mini-UAV-borne LIDAR system-AOEagle, developed by Academy of Opto-Electronics, Chinese Academy of Sciences, which mounted on a Multi-rotor unmanned aerial vehicle for complex terrain survey according to real test. Furthermore, the point cloud data was explored to validate its applicability for power line inspection, in terms of corridor and line laser point clouds; deformation detection of power towers, etc. The feasibility and advantages of AOEagle have been demonstrated by the promising results based on the real-measured data in the field of power line inspection.

Wind Doesn't Just Stop at the Earth's Surface

NASA Astrophysics Data System (ADS)

Clifton, A. J.

2017-12-01

Wind turbines are increasingly being installed in complex terrain such as the pre-Alpine regions of Germany, Austria, and other European Alpine regions, mountainous regions across USA and Canada, and many other parts of the world. In these areas, the system of the atmosphere, terrain, geology, people, and power system has is deeply interconnected but couplings are not completely known. This leads to challenging development conditions, increased cost of energy compared to flat terrain, and sometimes to tensions between different stakeholders. In this presentation, an overview of the wind energy system will be presented, and the challenges of developing wind energy in complex terrain will be highlighted. Results from several recent measurement campaigns and associated modelling carried out by members of WindForS will be used as examples. WindForS is a southern Germany-based research consortium of more than 20 groups at higher education and research institutes, with strong links to government and industry. Finally, the new WindForS wind energy research facility in complex terrain will be introduced. The new test site will be located in the hilly, forested terrain of the Swabian Alps between Stuttgart and Germany, and will consist of two wind turbines with four meteorological towers. The test site will be used for accompanying ecological research and will also have mobile eddy covariance measurement stations as well as bird and bat monitoring systems. Seismic and noise monitoring systems are also planned. The large number of auxiliary measurements at this facility are intended to allow the complete atmosphere-wind turbine-environment-people system to be characterized. A major focus of the presentation will be on opportunities for interdisciplinary collaboration between the atmospheric science and geosciences communities and other stakeholders.

Bald Mountain Fire, Eagle Cap Wilderness Area, Wallowa-Whitman National Forest, FARSITE analysis

Treesearch

LaWen Hollingsworth

2012-01-01

While the Near Term Fire Behavior analysis option in WFDSS is similar to FARSITE, the advantage of using FARSITE lies in the ability to use gridded winds which produces more reliable fire behavior results in complex terrain. A couple of FARSITE simulations were completed to evaluate fire growth and fire behavior in relation to the values, notably Red's Horse Ranch...

Computation of times of sunrise, sunset, and twilight in or near mountainous terrain

Treesearch

Bill C. Ryan

1977-01-01

An electronic calculator with trigonometric functions can be used to compute times of sunrise, sunset, or twilight, or time of desired illumination at any location in mountainous terrain. The method is more convenient and versatile, and less cumbersome than using tables. Latitude, longitude, elevation, day of the year (1 to 366), and slope to the horizon at the...

Predicting Southern Appalachian overstory vegetation with digital terrain data

Treesearch

Paul V. Bolstad; Wayne Swank; James Vose

1998-01-01

Vegetation in mountainous regions responds to small-scale variation in terrain, largely due to effects on both temperature and soil moisture. However, there are few studies of quantitative, terrain-based methods for predicting vegetation composition. This study investigated relationships between forest composition, elevation, and a derived index of terrain shape, and...

Methodology to estimate variations in solar radiation reaching densely forested slopes in mountainous terrain.

PubMed

Sypka, Przemysław; Starzak, Rafał; Owsiak, Krzysztof

2016-12-01

Solar radiation reaching densely forested slopes is one of the main factors influencing the water balance between the atmosphere, tree stands and the soil. It also has a major impact on site productivity, spatial arrangement of vegetation structure as well as forest succession. This paper presents a methodology to estimate variations in solar radiation reaching tree stands in a small mountain valley. Measurements taken in three inter-forest meadows unambiguously showed the relationship between the amount of solar insolation and the shading effect caused mainly by the contour of surrounding tree stands. Therefore, appropriate knowledge of elevation, aspect and tilt angles of the analysed planes had to be taken into consideration during modelling. At critical times, especially in winter, the diffuse and reflected components of solar radiation only reached some of the sites studied as the beam component of solar radiation was totally blocked by the densely forested mountain slopes in the neighbourhood. The cross-section contours and elevation angles of all obstructions are estimated from a digital surface model including both digital elevation model and the height of tree stands. All the parameters in a simplified, empirical model of the solar insolation reaching a given horizontal surface within the research valley are dependent on the sky view factor (SVF). The presented simplified, empirical model and its parameterisation scheme should be easily adaptable to different complex terrains or mountain valleys characterised by diverse geometry or spatial orientation. The model was developed and validated (R 2  = 0.92 , σ = 0.54) based on measurements taken at research sites located in the Silesian Beskid Mountain Range. A thorough understanding of the factors determining the amount of solar radiation reaching woodlands ought to considerably expand the knowledge of the water exchange balance within forest complexes as well as the estimation of site productivity.

Further study of terrain effects on the mesoscale spectrum of atmospheric motions

NASA Technical Reports Server (NTRS)

Jasperson, W. H.; Nastrom, G. D.; Fritts, D. C.

1990-01-01

Wind and temperature data collected on commercial airliners are used to investigate the effects of underlying terrain on mesoscale variability. These results expand upon those of Nastrom et al., by including all available data from the Global Atmospheric Sampling Program (GASP) and by more closely focusing on the coupling of variance with the roughness of the underlying terrain over mountainous regions. The earlier results, showing that variances are larger over mountains than over oceans or plains, with greatest increases at wavelengths below about 80 km, are confirmed. Statistical tests are used to confirm that these differences are highly significant. Over mountainous regions the roughness of the underlying terrain was parameterized from topographic data and it was found that variances are highly correlated with roughness and, in the troposphere, with background windspeed. Average variances over the roughest terrain areas range up to about ten times larger than those over the oceans. These results are found to follow the scaling with stability predicted in the framework of linenar gravity wave theory. The implications of these results for vertical transports of momentum and energy, assuming they are due to gravity waves and considering the effects of intermittency and anisotroy, are also discussed.

Geomorphic Units on Titan

NASA Astrophysics Data System (ADS)

Lopes, R. M. C.; Malaska, M. J.; Schoenfeld, A.; Birch, S. P.; Hayes, A. G., Jr.

2014-12-01

The Cassini-Huygens mission has revealed the surface of Titan in unprecedented detail. The Synthetic Aperture Radar (SAR) mode on the Cassini Titan Radar Mapper is able to penetrate clouds and haze to provide high resolution (~350 m spatial resolution at best) views of the surface geology. The instrument's other modes (altimetry, scatterometry, radiometry) also provide valuable data for interpreting the geology, as do other instruments on Cassini, in particular, the Imaging Science Subsystem (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS). Continuing the initial work described in Lopes et al. (2010, Icarus, 212, 744-750), we have established the major geomorphologic unit classes on Titan using data from flybys Ta through T92 (October 2004-July 2013). We will present the global distribution of the major classes of units and, where there are direct morphological contacts, describe how these classes of units relate to each other in terms of setting and emplacement history. The classes of units are mountainous/hummocky terrains, plains, dunes, labyrinthic terrains and lakes. The oldest classes of units are the mountainous/hummocky and the labyrinthic terrains. The mountainous/hummocky terrains consist of mountain chains and isolated radar-bright terrains. The labyrinthic terrains consist of highly incised dissected plateaux with medium radar backscatter. The plains are younger than both mountainous/hummocky and labyrinthic unit classes. Dunes and lakes are the youngest unit classes on Titan; no contact is observed between the dunes and lakes but it is likely that both processes are still active. We have identified individual features such as craters, channels, and candidate cryovolcanic features. Characterization and comparison of the properties of the unit classes and the individual features with data from radiometry, ISS, and VIMS provides information on their composition and possible provenance. We can use these correlations to also infer global distribution on regions not covered by SAR. This is particularly important as SAR data will not provide complete coverage of Titan by the end of the Cassini mission.

The Geology of Titan as Revealed by Cassini

NASA Astrophysics Data System (ADS)

Lopes, Rosaly M.; Malaska, Michael; Solomonidou, Anezina; Cassini RADAR Team

2015-08-01

The Cassini-Huygens mission has revealed the surface of Titan in unprecedented detail, enabling us to discern the different geomorphic units on the surface and constrain the relative times of emplacement. We used a combined dataset of Cassini’s multiple instruments and instrument modes: Synthetic Aperture Radar (SAR-RADAR), altimetry, scatterometry, imaging (ISS) and hyperspectral imaging (VIMS) to provide information on Titan’s surface geology. Continuing the initial work described in Lopes et al. [1], we established the major geomorphologic unit classes on Titan using data from flybys Ta through T92 (October 2004-July 2013). We will present the global distribution of the major classes of units and, where there are direct morphological contacts, describe how these classes of units relate to each other in terms of setting and emplacement history. The classes of units are mountainous/hummocky terrains, plains, dunes, labyrinthic terrains and lakes. The oldest classes of units are the mountainous/hummocky and the labyrinthic terrains. The mountainous/hummocky terrains consist of mountain chains and isolated radar-bright terrains. The labyrinthic terrains consist of highly incised dissected plateaus with medium radar backscatter. The plains are younger than both mountainous/hummocky and labyrinthic unit classes. Dunes and lakes are the youngest unit classes on Titan; no contact is observed between them but it is likely that both processes are still active. We have identified individual features such as craters, channels, and candidate cryovolcanic features. Characterization and comparison of the properties of the unit classes and the individual features with data from radiometry, ISS, and VIMS provides information on their composition and possible provenance. We can use these correlations to also infer global distribution on regions not covered by SAR. This is particularly important, as SAR data will not provide complete coverage of Titan by the end of the Cassini mission.References: [1] Lopes, R.M.C., et al. Icarus, 212, 744-750, 2010.

Geomorphic Units on Titan

NASA Astrophysics Data System (ADS)

Lopes, Rosaly; Malaska, Michael; Schoenfeld, Ashley; Birch, Samuel; Hayes, Alexander; Solomonidou, Anezina; Radebaugh, Jani

2015-04-01

The Cassini-Huygens mission has revealed the surface of Titan in unprecedented detail. The Synthetic Aperture Radar (SAR) mode on the Cassini Titan Radar Mapper is able to penetrate clouds and haze to provide high resolution (~350 m spatial resolution at best) views of the surface geology. The instrument's other modes (altimetry, scatterometry, radiometry) also provide valuable data for interpreting the geology, as do other instruments on Cassini, in particular, the Imaging Science Subsystem (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS). Continuing the initial work described in Lopes et al. (2010, Icarus, 212, 744-750), we have established the major geomorphologic unit classes on Titan using data from flybys Ta through T92 (October 2004-July 2013). We will present the global distribution of the major classes of units and, where there are direct morphological contacts, describe how these classes of units relate to each other in terms of setting and emplacement history. The classes of units are mountainous/hummocky terrains, plains, dunes, labyrinthic terrains and lakes. The oldest classes of units are the mountainous/hummocky and the labyrinthic terrains. The mountainous/hummocky terrains consist of mountain chains and isolated radar-bright terrains. The labyrinthic terrains consist of highly incised dissected plateaux with medium radar backscatter. The plains are younger than both mountainous/hummocky and labyrinthic unit classes. Dunes and lakes are the youngest unit classes on Titan; no contact is observed between the dunes and lakes but it is likely that both processes are still active. We have identified individual features such as craters, channels, and candidate cryovolcanic features. Characterization and comparison of the properties of the unit classes and the individual features with data from radiometry, ISS, and VIMS provides information on their composition and possible provenance. We can use these correlations to also infer global distribution on regions not covered by SAR. This is particularly important as SAR data will not provide complete coverage of Titan by the end of the Cassini mission.

Transpirational water use and its regulation in the mountainous terrain of S. Korea

NASA Astrophysics Data System (ADS)

Otieno Dennis, O.; Eunyoung, J.; Sinkyu, K.; Tenhunen, J. D.

2009-12-01

Quantifying water use by forests growing on complex mountainous terrain is difficult and understanding of controls on water use by these forests a challenge. Yet mountains are crucial as water towers and better understanding of their hydrology and ecology is critical for sustainable management. Consequently, there is a growing need for new research approaches designed with attention to the particular needs and constraints of large-scale studies and that have the potential to generate reliable and accurate data. The use of a combination of different sapflow-measurement techniques provides a unique opportunity to monitor water use by the understory and canopy forest tree species at micro-scale, allowing for accurate estimation of total forest water use. The obtained data, in conjunction with intensively measured climatic variables, allow for better understanding and interpretation of transpiration results. A research initiative under the International Training Group: Complex Terrain and Ecological Heterogeneity (TERRECO) seeks to address pertinent issues related to forest water use and production in complex terrain. Stem Heat balance (SHB) and Heat Dissipation techniques have been employed to measure sapflow in the understory woody plants and tree branches and on stems of canopy trees respectively. Measurements have been stratified to account for differences in tree sizes and species diversity. To better understand the data, we are intensively monitoring soil moisture at 5, 10 and 30 cm depths, in addition to a range of micrometeorology sensors that have been set up below, within and above the canopy. These measurements have been planned, taking into account altitudinal/elevation gradient, aspect and within site differences in species composition and tree sizes and to generate data for large-scale modeling of the entire catchment. A total of 70 trees from 9 species growing in six different locations at varying elevations and aspects are being monitored. Peak daily water use by trees during mid summer amounts to 45 kg d-1 but varies significantly with sapwood area. Within a species, there is a consistent relationship between tree size (DBH) and sapwood area irrespective of elevation. We have also established a common trend in the relationship between wood density and sap flux density (Js) that transcends the boundaries of species differences. These initial findings are critical for our planned upscaling of water use by the forest catchment. In addition to soil moisture, vapor pressure deficit (VPD) and light play a crucial regulatory role on forest water use. We are at the stage of establishing a common link that brings together micrometeorology and transpiration that will allow for large scale modeling of forest water use.

Geomorphological Mapping of Sputnik Planum and Surrounding Terrain on Pluto

NASA Astrophysics Data System (ADS)

White, Oliver; Stern, Alan; Weaver, Hal; Olkin, Cathy; Ennico, Kimberly; Young, Leslie; Moore, Jeff

2015-11-01

The New Horizons flyby of Pluto in July 2015 has provided the first few close-up images of the Kuiper belt object, which reveal it to have a highly diverse range of terrains, implying a complex geological history. The highest resolution images that have yet been returned are seven lossy 400 m/pixel frames that cover the majority of the prominent Plutonian feature informally named Sputnik Planum (all feature names are currently informal), and its surroundings. This resolution is sufficient to allow detailed geomorphological mapping of this area to commence. Lossless versions of all 15 frames that make up the mosaic will be returned in September 2015, and the map presented at DPS will incorporate the total area covered by these frames.Sputnik Planum, with an area of ~650,000 km2, is notable for its smooth appearance and apparent total lack of impact craters at 400 m/pixel resolution. The Planum actually displays a wide variety of textures across its expanse, which includes smooth and pitted plains to the south, polygonal terrain at its center (the polygons can reach tens of kilometers in size and are bounded by troughs that sometimes feature central ridges), and, to the north, darker polygonal terrain displaying patterns indicative of glacial flow. Within these plains there exist several well-defined outcrops of a mottled, light/dark unit that reach from several to tens of kilometers across. Separating Sputnik Planum from the dark, cratered equatorial terrain of Cthulhu Regio on its south-western margin is a unit of chaotically arranged mountains (Hillary Montes); similar mountainous units exist on the south and western margins. The northern margin is bounded by rugged, hilly, cratered terrain (Cousteau Rupes) into which ice of Sputnik Planum appears to be intruding in places. Terrain of similar relief exists to the east, but is much brighter than that to the north. The southernmost extent of the mosaic features a unit of rough, undulating terrain (Pandemonium Dorsa) that displays very few impact craters at 400 m/pixel resolution.This work was supported by the NASA New Horizons project.

Response of rock-fissure seepage to snowmelt in Mount Taihang slope-catchment, North China.

PubMed

Cao, Jiansheng; Liu, Changming; Zhang, Wanjun

2013-01-01

The complex physiographic and hydrogeological systems of mountain terrains facilitate intense rock-fissure seepages and multi-functional ecological interactions. As mountain eco-hydrological terrains are the common water sources of river basins across the globe, it is critical to build sufficient understanding into the hydrological processes in this unique ecosystem. This study analyzes infiltration and soil/rock-fissure seepage processes from a 65 mm snowfall/melt in November 2009 in the typical granitic gneiss slope catchment in the Taihang Mountains. The snowfall, snowmelt and melt-water processes are monitored using soil-water time-domain reflectometry (TDR) probes and tipping bucket flowmeters. The results suggest that snowmelt infiltration significantly influences soil/rock water seepage in the 0-100 cm soil depth of the slope-catchment. It is not only air temperature that influences snowmelt, but also snowmelt infiltration and rock-fissure seepage. Diurnal variations in rock-fissure seepage are in close correlation with air temperature (R(2) > 0.7). Temperature also varies with soil/rock water viscosity, which element in turn influences soil/rock water flow. Invariably, water dynamics in the study area is not only a critical water supply element for domestic, industrial and agricultural uses, but also for food security and social stability.

Remote sensing for environmental protection of the eastern Mediterranean rugged mountainous areas, Lebanon

NASA Astrophysics Data System (ADS)

Khawlie, M.; Awad, M.; Shaban, A.; Bou Kheir, R.; Abdallah, C.

Lying along the eastern Mediterranean coast with elevated mountain chains higher than 2500 m straddling its terrain, Lebanon is a country of natural beauty and is thus attracting tourism. However, with a population density exceeding 800/km 2 and a rugged steep sloping land, problems abound in the country calling for holistic-approach studies. Only remote sensing, whose use is new in Lebanon can secure such needed studies within a scientific and pragmatic framework. The paper demonstrates for the concerned themes, the innovative use of remote sensing in such a difficult terrain, giving three examples of major environmental problems in the coastal mountains. Only few studies have so far focused on those mountains, notably application of remote sensing. The rugged mountainous terrain receives considerable rain, but the water is quickly lost running on the steep slopes, or infiltrating through fractures and the karstic conduits into the subsurface. Field investigations are difficult to achieve, therefore, remote sensing helps reveal various surface land features important in reflecting water feeding into the subsurface. Optical, radar and thermal infrared remotely sensed data cover a wide spectrum serving that purpose. A map of preferential groundwater accumulation potential is produced. It can serve for better water exploitation as well as protection. Because the terrain is karstic and rugged, the subsurface water flow is difficult to discern. Any pollution at a certain spot would certainly spread around. This constitutes the second example of environmental problems facing the mountainous areas in Lebanon. An integrated approach using remote sensing and geographic information systems (GIS) gives good results in finding out the likelihood of how pollution, or contaminants, can selectively move in the subsurface. A diagnostic analysis with a GIS-type software acts as a guide producing indicative maps for the above purpose. The third example given deals with the problem of losing soil, which is a very vital source in such mountainous land. With steep slopes, torrential rain and improper human interference, run-off is high and water-soil erosion is continuously deteriorating the land cover. Remote sensing can facilitate studying the factors enhancing the process, such as soil type, slope gradient, drainage, geology and land cover. Digital elevation models created from SAR imagery contribute significantly to assessing vulnerability of hydric-soil erosion over such a difficult terrain. GIS layers of the above factors are integrated with erosional criteria to produce a risk map of soil erosion. Results indicate that 36% of the Lebanese terrain is under threat of high-level erosion, and 52% of that is concentrated in the rugged mountainous regions.

Gravity Wave Breaking over the Central Alps: Role of Complex Terrain.

NASA Astrophysics Data System (ADS)

Jiang, Qingfang; Doyle, James D.

2004-09-01

The characteristics of gravity waves excited by the complex terrain of the central Alps during the intensive observational period (IOP) 8 of the Mesoscale Alpine Programme (MAP) is studied through the analysis of aircraft in situ measurements, GPS dropsondes, radiosondes, airborne lidar data, and numerical simulations.Mountain wave breaking occurred over the central Alps on 21 October 1999, associated with wind shear, wind turning, and a critical level with Richardson number less than unity just above the flight level (5.7 km) of the research aircraft NCAR Electra. The Electra flew two repeated transverses across the Ötztaler Alpen, during which localized turbulence was sampled. The observed maximum vertical motion was 9 m s-1, corresponding to a turbulent kinetic energy (TKE) maximum of 10.5 m2 s-2. Spectrum analysis indicates an inertia subrange up to 5-km wavelength and multiple energy-containing spikes corresponding to a wide range of wavelengths.Manual analysis of GPS dropsonde data indicates the presence of strong flow descent and a downslope windstorm over the lee slope of the Ötztaler Alpen. Farther downstream, a transition occurs across a deep hydraulic jump associated with the ascent of isentropes and local wind reversal. During the first transverse, the turbulent region is convectively unstable as indicated by a positive sensible heat flux within the turbulent portion of the segment. The TKE derived from the flight-level data indicates multiple narrow spikes, which match the patterns shown in the diagnosed buoyancy production rate of TKE. The turbulence is nonisotropic with the major TKE contribution from the -wind component. The convectively unstable zone is advected downstream during the second transverse and the turbulence becomes much stronger and more isotropic.The downslope windstorm, flow descent, and transition to turbulence through a hydraulic jump are captured by a real-data Coupled Ocean Atmosphere Mesoscale Predition System (COAMPS) simulation. Several idealized simulations are performed motivated by the observations of multiscale waves forced by the complex terrain underneath. The simulations indicate that multiscale terrain promotes wave breaking, increases mountain drag, and enhances the downslope winds and TKE generation.

Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program

DTIC Science & Technology

2017-05-09

resolution land-surface data with comparison to observations . These will be extended to higher resolution with the immersed boundary method when...To) 09/05/2017 Final 1 Jun 1 1 to 30 May 17 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER Mountain Terrain Atmospheric Modeling and Observations ...OF NOTRE DAME DU LAC REPORT NUMBER RESEARCH AND SPONSORED PROGRAMS Final 940 GRACE HALL NOTRE DAME, IN 46556-5602 9. SPONSORING/MONITORING AGENCY

Accuracy of retrieving temperature and humidity profiles by ground-based microwave radiometry in truly complex terrain

NASA Astrophysics Data System (ADS)

Massaro, G.; Stiperski, I.; Pospichal, B.; Rotach, M. W.

2015-03-01

Within the Innsbruck Box project, a ground-based microwave radiometer (RPG-HATPRO) was operated in the Inn Valley (Austria), in very complex terrain, between September 2012 and May 2013 to obtain temperature and humidity vertical profiles of the full troposphere with a specific focus on the valley boundary layer. The profiles obtained by the radiometer with different retrieval algorithms based on different climatologies, are compared to local radiosonde data. A retrieval that is improved with respect to the one provided by the manufacturer, based on better resolved data, shows a significantly smaller root mean square error (RMSE), both for the temperature and humidity profiles. The improvement is particularly substantial at the heights close to the mountaintop level and in the upper troposphere. Lower level inversions, common in an alpine valley, are resolved to a satisfactory degree. On the other hand, upper level inversions (above 1200 m) still pose a significant challenge for retrieval. For this purpose, specialized retrieval algorithms were developed by classifying the radiosonde climatologies into specialized categories according to different criteria (seasons, daytime, nighttime) and using additional regressors (e.g., measurements from mountain stations). The training and testing on the radiosonde data for these specialized categories suggests that a classification of profiles that reproduces meaningful physical characteristics can yield improved targeted specialized retrievals. A really new and very promising method of improving the profile retrieval in a mountain region is adding further information in the retrieval, such as the surface temperature at fixed levels along a topographic slope or from nearby mountain tops.

OLYMPEX: A Ground Validation Campaign on the Olympic Peninsula in the Pacific Northwest

NASA Astrophysics Data System (ADS)

McMurdie, L. A.; Houze, R.; Lettenmaier, D. P.; Lundquist, J. D.; Petersen, W. A.; Schwaller, M.

2013-12-01

The Global Precipitation Measurement (GPM) Mission is scheduled for launch in early 2014. It's primary objective is to measure rain and snow globally especially in areas lacking surface observations or ground-based radar coverage. The GPM satellites will need to be able to detect solid and liquid precipitation over a wide range of intensities, locations and regimes. The core satellite of GPM will carry a passive microwave radiometer, the GPM Microwave Imager (GMI) and the first space-borne Ku/Ka band Dual Frequency Precipitation Radar (DPR). To satisfy the GPM measurement requirements and to assess how remotely sensed precipitation can be applied to a range of data applications (e.g. determining storm structures and monitoring flooding events and droughts) ground validation (GV) field campaigns are vital. As such, the Olympic Mountains GV Experiment (OLYMPEX) is planned for November 2015 - February 2016. The Olympic Peninsula is an ideal location to conduct a GV campaign. It is situated in the northwest corner of Washington State within an active mid-latitude winter storm track. It receives among the highest annual precipitation amounts in North America ranging from over 2500 mm on the coast to 4000 mm in the mountainous interior. In one compact area, the Olympic peninsula ranges from ocean to coast to land to mountains. This unique venue will enable the field campaign to monitor both upstream precipitation characteristics and processes over the ocean and their modification over complex terrain. Measuring precipitation from space in coastal and mountainous regions is challenging; however, the unique characteristics of the Olympic Peninsula make OLYMPEX a unique and viable opportunity to address these challenges and quantify the sources of variability and uncertainty in coastal and complex terrain. The scientific goals of the OLYMPEX field campaign include physical validation of satellite algorithms, precipitation processes in complex terrain, hydrological applications and modeling studies. In order to address these goals, a wide variety of existing and new observations and instrumentation is planned. These include an in situ surface observing networks of meteorological stations, rain and snow gauges, surface microphysical measurements and snowpack surveys. Surface-based remote instrumentation will include the existing coastal radar at Langley, WA, the NOAA/ESRL Atmospheric River Observatory at Westport, WA, and planned additional radars such as the NASA N-Pol S-Band dual-polarimetric and NASA Dual-Frequency Dual-Polarimetric Doppler (D3R) scanning radars for PPI and RHI scanning over the west slopes of the Olympics, and other mobile vertically-pointing radars. Several instrumented aircraft are likely to participate. The NASA DC-8 will be equipped with a Ka-Ku band dual-frequency radar and passive microwave sensors that simulate those on the GPM Core satellite. The University of North Dakota Citation will measure in situ microphysics. The aircraft measurements will determine upstream thermodynamic and moisture conditions, sample particle types and sizes for comparison with those employed in the satellite algorithm, and act as a proxy for the satellite itself. The ground-based measurements will test how well the satellite proxy measurements determine the rain and snow over complex terrain.

Recent developments and assessment of a three-dimensional PBL parameterization for improved wind forecasting over complex terrain

NASA Astrophysics Data System (ADS)

Kosovic, B.; Jimenez, P. A.; Haupt, S. E.; Martilli, A.; Olson, J.; Bao, J. W.

2017-12-01

At present, the planetary boundary layer (PBL) parameterizations available in most numerical weather prediction (NWP) models are one-dimensional. One-dimensional parameterizations are based on the assumption of horizontal homogeneity. This homogeneity assumption is appropriate for grid cell sizes greater than 10 km. However, for mesoscale simulations of flows in complex terrain with grid cell sizes below 1 km, the assumption of horizontal homogeneity is violated. Applying a one-dimensional PBL parameterization to high-resolution mesoscale simulations in complex terrain could result in significant error. For high-resolution mesoscale simulations of flows in complex terrain, we have therefore developed and implemented a three-dimensional (3D) PBL parameterization in the Weather Research and Forecasting (WRF) model. The implementation of the 3D PBL scheme is based on the developments outlined by Mellor and Yamada (1974, 1982). Our implementation in the Weather Research and Forecasting (WRF) model uses a pure algebraic model (level 2) to diagnose the turbulent fluxes. To evaluate the performance of the 3D PBL model, we use observations from the Wind Forecast Improvement Project 2 (WFIP2). The WFIP2 field study took place in the Columbia River Gorge area from 2015-2017. We focus on selected cases when physical phenomena of significance for wind energy applications such as mountain waves, topographic wakes, and gap flows were observed. Our assessment of the 3D PBL parameterization also considers a large-eddy simulation (LES). We carried out a nested LES with grid cell sizes of 30 m and 10 m covering a large fraction of the WFIP2 study area. Both LES domains were discretized using 6000 x 3000 x 200 grid cells in zonal, meridional, and vertical direction, respectively. The LES results are used to assess the relative magnitude of horizontal gradients of turbulent stresses and fluxes in comparison to vertical gradients. The presentation will highlight the advantages of the 3D PBL scheme in regions of complex terrain.

Separating local topography from snow effects on momentum roughness in mountain regions

NASA Astrophysics Data System (ADS)

Diebold, M.; Katul, G. G.; Calaf, M.; Lehning, M.; Parlange, M. B.

2013-12-01

Parametrization of momentum surface roughness length in mountainous regions continues to be an active research topic given its application to improved weather forecasting and sub-grid scale representation of mountainous regions in climate models. A field campaign was conducted in the Val Ferret watershed (Swiss Alps) to assess the role of topographic variability and snow cover on momentum roughness. To this end, turbulence measurements in a mountainous region with and without snow cover have been analyzed. A meteorological mast with four sonic anemometers together with temperature and humidity sensors was installed at an elevation of 2500 m and data were obtained from October 2011 until May 2012. Because of the long-term nature of these experiments, natural variability in mean wind direction allowed a wide range of terrain slopes and snow depths to be sampled. A theoretical framework that accounted only for topographically induced pressure perturbations in the mean momentum balance was used to diagnose the role of topography on the effective momentum roughness height as inferred from the log-law. Surface roughness depended systematically on wind direction but was not significantly influenced by the presence of snow depth variation. Moreover, the wind direction and so the surface roughness influenced the normalized turbulent kinetic energy, which in theory should not depend on these factors in the near-neutral atmospheric surface layer. The implications of those findings to modeling momentum roughness heights and turbulent kinetic energy (e.g. in conventional K-epsilon closure) in complex terrain are briefly discussed.

Complex mountain terrain and disturbance history drive variation in forest aboveground live carbon density in the western Oregon Cascades, USA

PubMed Central

Zald, Harold S.J.; Spies, Thomas A.; Seidl, Rupert; Pabst, Robert J.; Olsen, Keith A.; Steel, E. Ashley

2016-01-01

Forest carbon (C) density varies tremendously across space due to the inherent heterogeneity of forest ecosystems. Variation of forest C density is especially pronounced in mountainous terrain, where environmental gradients are compressed and vary at multiple spatial scales. Additionally, the influence of environmental gradients may vary with forest age and developmental stage, an important consideration as forest landscapes often have a diversity of stand ages from past management and other disturbance agents. Quantifying forest C density and its underlying environmental determinants in mountain terrain has remained challenging because many available data sources lack the spatial grain and ecological resolution needed at both stand and landscape scales. The objective of this study was to determine if environmental factors influencing aboveground live carbon (ALC) density differed between young versus old forests. We integrated aerial light detection and ranging (lidar) data with 702 field plots to map forest ALC density at a grain of 25 m across the H.J. Andrews Experimental Forest, a 6369 ha watershed in the Cascade Mountains of Oregon, USA. We used linear regressions, random forest ensemble learning (RF) and sequential autoregressive modeling (SAR) to reveal how mapped forest ALC density was related to climate, topography, soils, and past disturbance history (timber harvesting and wildfires). ALC increased with stand age in young managed forests, with much greater variation of ALC in relation to years since wildfire in old unmanaged forests. Timber harvesting was the most important driver of ALC across the entire watershed, despite occurring on only 23% of the landscape. More variation in forest ALC density was explained in models of young managed forests than in models of old unmanaged forests. Besides stand age, ALC density in young managed forests was driven by factors influencing site productivity, whereas variation in ALC density in old unmanaged forests was also affected by finer scale topographic conditions associated with sheltered sites. Past wildfires only had a small influence on current ALC density, which may be a result of long times since fire and/or prevalence of non-stand replacing fire. Our results indicate that forest ALC density depends on a suite of multi-scale environmental drivers mediated by complex mountain topography, and that these relationships are dependent on stand age. The high and context-dependent spatial variability of forest ALC density has implications for quantifying forest carbon stores, establishing upper bounds of potential carbon sequestration, and scaling field data to landscape and regional scales. PMID:27041818

Stratified Turbulence Measurements in Complex Terrain Using Hot-film Probes and a Collocated Sonic Anemometer

NASA Astrophysics Data System (ADS)

Hocut, C.; Kit, E.; Liberzon, D.; Fernando, H. J. S.; Materhorn Team

2014-11-01

In the fall of 2012 and spring 2013, the Mountain Terrain Atmospheric Modeling and Observations Program (MATERHORN) conducted extensive field experiments at the Granite Mountain Atmospheric Science Testbed (GMAST), US Army Dugway Proving Grounds (DPG), Utah. This provided a unique opportunity to deploy tower mounted three-dimensional hot-film combo probes, consisting of sonic anemometers collocated with hot-film anemometers able to respond to the wind direction. The combo probes follow mean winds using a feedback control loop and use a Neural Network to calibrate the hot-films in-situ. Once calibrated, these probes can handle a vast range of background flow conditions and scales from mesoscale flow down to the Kolmogorov scale. Of particular interest are the observed variation in velocity spectra during the evenings. Sometimes the velocity spectra shows the turbulence is Kolmogorov and is isotropic at small scales while in other spectra there is evidence of turbulence production at finer scales. An explanation on different spectral shapes will be presented as well as the relevant length/time scales of the production events. Funded by ONR Grant N00014-11-1-0709.

Estimation of Solar Radiation on Building Roofs in Mountainous Areas

NASA Astrophysics Data System (ADS)

Agugiaro, G.; Remondino, F.; Stevanato, G.; De Filippi, R.; Furlanello, C.

2011-04-01

The aim of this study is estimating solar radiation on building roofs in complex mountain landscape areas. A multi-scale solar radiation estimation methodology is proposed that combines 3D data ranging from regional scale to the architectural one. Both the terrain and the nearby building shadowing effects are considered. The approach is modular and several alternative roof models, obtained by surveying and modelling techniques at varying level of detail, can be embedded in a DTM, e.g. that of an Alpine valley surrounded by mountains. The solar radiation maps obtained from raster models at different resolutions are compared and evaluated in order to obtain information regarding the benefits and disadvantages tied to each roof modelling approach. The solar radiation estimation is performed within the open-source GRASS GIS environment using r.sun and its ancillary modules.

The assessment of environmentally sensitive forest road construction in Calabrian pine forest areas of Turkey.

PubMed

Tunay, Metin

2006-07-01

Forest road construction by bulldozers in Calabrian Pine (Pinus brutia Ten.) forests on mountainous terrain of Turkey causes considerable damage to the environment and the forest standing alongside the road. This situation obliges a study of environmentally sound road construction in Turkey. This study was carried out in 4 sample sites of Antalya Forest Directorate in steep (34-50% gradient) and very steep terrain (51-70% gradient) conditions with bulldozer and excavator machine and direct damages to forest during road construction was determined, including forest area losses and damages to downhill trees in mountainous areas. It was determined that in steep terrain when excavators were used, less forest area (22.16%) was destroyed compared to bulldozers and 26.54% less area in very steep terrain. The proportion of damage on trees where bulldozer worked was nearly twofold higher than excavator was used. The results of this research show that the environmentally sensitive techniques applied for the road construction projects are considerably superior to the traditional use of bulldozers on steep slopes. The environmentally sound forest road construction by use of excavator must be considered an appropriate and reliable solution for mountainous terrain where areas of sensitive forest ecosystems are to be opened up.

Eddy covariance measurements of carbon dioxide, latent and sensible energy fluxes above a meadow on a mountain slope

PubMed Central

Hammerle, Albin; Haslwanter, Alois; Schmitt, Michael; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander; Wohlfahrt, Georg

2014-01-01

Carbon dioxide, latent and sensible energy fluxes were measured by means of the eddy covariance method above a mountain meadow situated on a steep slope in the Stubai Valley/Austria, based on the hypothesis that, due to the low canopy height, measurements can be made in the shallow equilibrium layer where the wind field exhibits characteristics akin to level terrain. In order to test the validity of this hypothesis and to identify effects of complex terrain in the turbulence measurements, data were subjected to a rigorous testing procedure using a series of quality control measures established for surface layer flows. The resulting high-quality data set comprised 36 % of the original observations, the substantial reduction being mainly due to a change in surface roughness and associated fetch limitations in the wind sector dominating during nighttime and transition periods. The validity of the high-quality data set was further assessed by two independent tests: i) a comparison with the net ecosystem carbon dioxide exchange measured by means of ecosystem chambers and ii) the ability of the eddy covariance measurements to close the energy balance. The net ecosystem CO2 exchange measured by the eddy covariance method agreed reasonably with ecosystem chamber measurements. The assessment of the energy balance closure showed that there was no significant difference in the correspondence between the meadow on the slope and another one situated on flat ground at the bottom of the Stubai Valley, available energy being underestimated by 28 and 29 %, respectively. We thus conclude that, appropriate quality control provided, the eddy covariance measurements made above a mountain meadow on a steep slope are of similar quality as compared to flat terrain. PMID:24465032

Io: Mountains and crustal extension

NASA Technical Reports Server (NTRS)

Heath, M. J.

1985-01-01

It is argued that there is good reason to conclude that mountains on Io, like those on Earth, are subject to growth and decay. The decay of mountains will be assisted by the ability of SO sub 2 to rot silicate rock and by explosive escape of sub-surface SO sub 2 from aquifers (Haemus Mons is seen to be covered by bright material, presumably fallout from a SO sub 2 rich plume which had been active on the mountain flanks). On the west side of the massif at 10 degrees S, 270 degrees W a rugged surface consists of long ridges running perpendicular to the downslope direction, suggesting tectonic denudation with crustal blocks sliding down the mountain flank. Tectonic denudation may be assisted, as in the case of the Bearpaw Mountains, Montana by overloading mountain flanks with volcanic products. The surfaces of some massifs exhibit a well developed, enigmatic corrugated terrain, consisting of complex ridge systems. Ridges may bifurcate, anastomose to form closed depressions and form concentric loops. Taken together, observations of morphology, heat flux, surface deposits and styles of volcanism may point to the existence of lithosphere domains with distinct compositions and tectonic regimes.

Characterizing the Linkages Between landform and Precipitation Regime in the Sierra Madre Meridional and in the Andes

NASA Astrophysics Data System (ADS)

Giovannettone, J. P.; Barros, A. P.

2005-12-01

Mountains play an important role in the hydrologic cycle in many parts of the world. About 25% of the world's population lives in mountainous terrain, and 60% of people rely on freshwater from mountainous regions for drinking water and other purposes. This is especially the case in the western US, in Central America and along the Andes. Whereas quantitative estimation of precipitation in mountainous regions is of critical importance, sparse raingauge networks and the operational difficulties of ground-based radar in the vicinity of high terrain, leave us without substantive observations to work with. By contrast, satellites provide a unique opportunity to look at large regions simultaneously and at high resolution. Although terrain complexity can also cause substantial uncertainty in the interpretation of remotely-sensed data, there is great value in the small-scale structure captured by high spatial resolution sensors. A comprehensive study including surface measurements, observations from the NASA TRMM satellite, and coupled land-atmosphere modeling to characterize the diurnal cycle of precipitation over the Sierra Madre Meridional (east of Mexico City) and over the Andes is currently under way. The objective of this work is to investigate the role of landform as the organizing principle of convective activity in mountainous regions and to determine whether this spatial organization can be linked to the diurnal cycle of rainfall. For this purpose, TRMM data were analyzed over the Sierra Madre and Andes Mountains using an algorithm developed by Nesbitt et al. (2000) to determine the location of precipitation features (PF's) over a time period extending from 1998 to 2004. The algorithm uses two types of data provided by the TRMM satellite: the near-surface precipitation radar (PR) and the TRMM Microwave Imager (TMI) polarization-corrected temperatures (PCT's) at 85.5 GHz. A PF is defined as an area of 75 km2 or greater in which reflectivities are greater than 20 dBZ and PCT's are less than 250 K. Diurnal, seasonal, and interannual variabilities in the number of PF's will be presented. Analyses over Mexico are performed during the summer season extending from May through September(i.e. the monsoon season), and those over South America are performed during their summer season from November to March. The results are compared to previous results over the Himalayas, and linkages between cloudiness, large-scale circulations, orography, and rainfall are proposed.

Scientific exploration of low-gravity planetary bodies using the Highland Terrain Hopper

NASA Astrophysics Data System (ADS)

Mège, D.; Grygorczuk, J.; Gurgurewicz, J.; Wiśniewski, Ł.; Rickman, H.; Banaszkiewicz, M.; Kuciński, T.; Skocki, K.

2013-09-01

Field geoscientists need to collect three-dimensional data in order characterise the lithologic succession and structure of terrains, recontruct their evolution, and eventually reveal the history of a portion of the planet. This is achieved by walking up and down mountains and valleys, interpreting geological and geophysical traverses, and reading measures made at station located at key sites on mountain peaks or rocky promontories. These activities have been denied to conventional planetary exploration rovers because engineering constraints for landing are strong, especially in terms of allowed terrain roughness and slopes. The Highland Terrain Hopper, a new, light and robust locomotion system, addresses the challenge of accessing most areas on low-gravity planetary body for performing scientific observations and measurements, alone or as part of a hopper commando. Examples of geological applications on Mars and the Moon are given.

Atmospheric stability effects on wind fields and scalar mixing within and just above a subalpine forest in sloping terrain

USGS Publications Warehouse

Burns, Sean P.; Sun, Jielun; Lenschow, D.H.; Oncley, S.P.; Stephens, B.B.; Yi, C.; Anderson, D.E.; Hu, Jiawen; Monson, Russell K.

2011-01-01

Air temperature Ta, specific humidity q, CO2 mole fraction ??c, and three-dimensional winds were measured in mountainous terrain from five tall towers within a 1 km region encompassing a wide range of canopy densities. The measurements were sorted by a bulk Richardson number Rib. For stable conditions, we found vertical scalar differences developed over a "transition" region between 0.05 < Rib < 0.5. For strongly stable conditions (Rib > 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability. The relationships q and ??c have with Rib are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO2 near the ground being 5-7 ??mol mol-1 larger than aloft, even with strong above-canopy winds (near-neutral conditions). We found Rib-binning to be a useful tool for evaluating vertical scalar mixing; however, additional information (e.g., pressure gradients, detailed vegetation/topography, etc.) is needed to fully explain the subcanopy wind patterns. Implications of our results for CO2 advection over heterogenous, complex terrain are discussed. ?? 2010 Springer Science+Business Media B.V.

Near-infrared spectral mapping of Titan's mountains and channels

USGS Publications Warehouse

Barnes, J.W.; Radebaugh, J.; Brown, R.H.; Wall, S.; Soderblom, L.; Lunine, J.; Burr, D.; Sotin, Christophe; Le, Mouelic S.; Rodriguez, S.; Buratti, B.J.; Clark, R.; Baines, K.H.; Jaumann, R.; Nicholson, P.D.; Kirk, R.L.; Lopes, R.; Lorenz, R.D.; Mitchell, Ken; Wood, C.A.

2007-01-01

We investigate the spectral reflectance properties of channels and mountain ranges on Titan using data from Cassini's Visual and Infrared Mapping Spectrometer (VIMS) obtained during the T9 encounter (26 December 2005). We identify the location of channels and mountains using synthetic aperture radar maps obtained from Cassini's RADAR instrument during the T13 (30 April 2006) flyby. Channels are evident even in VIMS imaging with spatial resolution coarser than the channel size. The channels share spectral characteristics with Titan's dark blue terrain (e.g., the Huygens landing site) that is consistent with an enhancement in water ice content relative to the rest of Titan. We use this fact to measure widths of ???1 km for the largest channels. Comparison of the data sets shows that in our study area within the equatorial bright spectral unit east of Xanadu, mountains are darker and bluer than surrounding smooth terrain. These results are consistent with the equatorial bright terrain possessing a veneer of material that is thinner in the regions where there are mountains and streambeds that have likely undergone more recent and extensive erosion. We suggest a model for the geographic relationship of the dark blue, dark brown, and equatorial bright spectral units based on our findings. Copyright 2007 by the American Geophysical Union.

Reference evapotranspiration from coarse-scale and dynamically downscaled data in complex terrain: Sensitivity to interpolation and resolution

NASA Astrophysics Data System (ADS)

Strong, Courtenay; Khatri, Krishna B.; Kochanski, Adam K.; Lewis, Clayton S.; Allen, L. Niel

2017-05-01

The main objective of this study was to investigate whether dynamically downscaled high resolution (4-km) climate data from the Weather Research and Forecasting (WRF) model provide physically meaningful additional information for reference evapotranspiration (E) calculation compared to the recently published GridET framework that uses interpolation from coarser-scale simulations run at 32-km resolution. The analysis focuses on complex terrain of Utah in the western United States for years 1985-2010, and comparisons were made statewide with supplemental analyses specifically for regions with irrigated agriculture. E was calculated using the standardized equation and procedures proposed by the American Society of Civil Engineers from hourly data, and climate inputs from WRF and GridET were debiased relative to the same set of observations. For annual mean values, E from WRF (EW) and E from GridET (EG) both agreed well with E derived from observations (r2 = 0.95, bias < 2 mm). Domain-wide, EW and EG were well correlated spatially (r2 = 0.89), however local differences ΔE =EW -EG were as large as +439 mm year-1 (+26%) in some locations, and ΔE averaged +36 mm year-1. After linearly removing the effects of contrasts in solar radiation and wind speed, which are characteristically less reliable under downscaling in complex terrain, approximately half the residual variance was accounted for by contrasts in temperature and humidity between GridET and WRF. These contrasts stemmed from GridET interpolating using an assumed lapse rate of Γ = 6.5 K km-1, whereas WRF produced a thermodynamically-driven lapse rate closer to 5 K km-1 as observed in mountainous terrain. The primary conclusions are that observed lapse rates in complex terrain differ markedly from the commonly assumed Γ = 6.5 K km-1, these lapse rates can be realistically resolved via dynamical downscaling, and use of constant Γ produces differences in E of order as large as 102 mm year-1.

Meso-beta scale numerical simulation studies of terrain-induced jet streak mass/momentum perturbations

NASA Technical Reports Server (NTRS)

Lin, Yuh-Lang; Kaplan, Michael L.

1992-01-01

Work performed during the report period is summarized. The first numerical experiment which was performed on the North Carolina Supercomputer Center's CRAY-YMP machine during the second half of FY92 involved a 36 hour simulation of the CCOPE case study. This first coarse-mesh simulation employed the GMASS model with a 178 x 108 x 32 matrix of grid points spaced approximately 24 km apart. The initial data was comprised of the global 2.5 x 2.5 degree analyses as well as all available North American rawinsonde data valid at 0000 UTC 11 July 1981. Highly-smoothed LFM-derived terrain data were utilized so as to determine the mesoscale response of the three-dimensional atmosphere to weak terrain forcing prior to including the observed highly complex terrain of the northern Rocky Mountain region. It was felt that the model should be run with a spectrum of terrain geometries, ranging from observed complex terrain to no terrain at all, to determine how crucial the terrain was in forcing the mesoscale phenomena. Both convection and stratiform (stable) precipitation were not allowed in this simulation so that their relative importance could be determined by inclusion in forth-coming simulations. A full suite of planetary boundary layer forcing was allowed in the simulation, including surface sensible and latent heat fluxes employing the Blakadar PBL formulation. The details of this simulation, which in many ways could be considered the control simulation, including the important synoptic-scale, meso-alpha scale, and meso-beta scale circulations is described. These results are compared to the observations diagnosed by Koch and his colleagues as well as hypotheses set forth in the project proposal for terrain-influences upon the jet stream and their role in the generation of mesoscale wave phenomenon. The fundamental goal of the analyses being the discrimination among background geostrophic adjustment, terrain influences, and shearing instability in the initiation and maintainance of mesoscale internal wave phenomena. Based upon these findings, FY93 plans are discussed. A review of linear theory and theoretical modeling of a geostrophic zonal wind anomaly is included.

Preliminary report on the geology and gold mineralization of the South Pass granite-greenstone terrain, Wind River Mountains, western Wyoming (US)

NASA Technical Reports Server (NTRS)

Hausel, W. D.

1986-01-01

The South Pass granite-greenstone terrain lies near the southern tip of the Wind River Mountains of western Wyoming. This Archean supracrustal pile has been Wyoming's most prolific source of gold and iron ore. From 1962 to 1983, more than 90 million tons of iron ore were recovered from oxide-facies banded iron formation, and an estimated 325,000 ounces of gold were mined from metagreywacke-hosted shears and associated placers. Precambrian rocks at South Pass are unconformably overlain by Paleozoic sediments along the northeast flank, and a Tertiary pediment buries Archean supracrustals on the west and south. To the northwest, the supracrustals terminate against granodiorite of the Louis Lake batholith; to the east, the supracrustals terminate against granite of the Granite Mountains batholith. The Louis Lake granodiorite is approximately 2,630 + or - 20 m.y. old, and the Granite Mountains granite averages 2,600 m.y. old. The geometry of the greenstone belt is best expressed as a synform that has been modified by complex faulting and folding. Metamorphism is amphibolite grade surrounding a small island of greenschist facies rocks. The younger of the Archean supracrustal successions is the Miners Delight Formation. This unit yielded a Rb-Sr isochron of 2,800 m.y. A sample of galena from the Snowbird Mine within the Miners Delight Formation yielded a model age averaging 2,750 m.y. The Snowbird mineralization appears to be syngenetic and is hosted by metavolcanics of calc-alkaline affinity. Discussion follows.

Observation and simulation of near-surface wind and its variation with topography in Urumqi, West China

NASA Astrophysics Data System (ADS)

Jin, Lili; Li, Zhenjie; He, Qing; Miao, Qilong; Zhang, Huqiang; Yang, Xinghua

2016-12-01

Near-surface wind measurements obtained with five 100-m meteorology towers, 39 regional automatic stations, and simulations by the Weather Research and Forecasting (WRF) model were used to investigate the spatial structure of topography-driven flows in the complex urban terrain of Urumqi, China. The results showed that the wind directions were mainly northerly and southerly within the reach of 100 m above ground in the southern suburbs, urban area, and northern suburbs, which were consistent with the form of the Urumqi gorge. Strong winds were observed in southern suburbs, whereas the winds in the urban, northern suburbs, and northern rural areas were weak. Static wind occurred more frequently in the urban and northern rural areas than in the southern suburbs. In the southern suburbs, wind speed was relatively high throughout the year and did not show significant seasonal variations. The average annual wind speed in this region varied among 1.9-5.5, 1.1-3.6, 1.2-4.3, 1.2-4.3, and 1.1-3.5 m s -1 within the reach of 100 m above ground at Yannanlijiao, Shuitashan, Liyushan, Hongguangshan, and Midong, respectively. The flow characteristics comprised more airflows around the mountain, where the convergence and divergence were dominated by the terrain in eastern and southwestern Urumqi. Further analysis showed that there was a significant mountain-valley wind in spring, summer, and autumn, which occurred more frequently in spring and summer for 10-11 h in urban and northern suburbs. During daytime, there was a northerly valley wind, whereas at night there was a southerly mountain wind. The conversion time from the mountain wind to the valley wind was during 0800-1000 LST (Local Standard Time), while the conversion from the valley wind to the mountain wind was during 1900-2100 LST. The influence of the mountain-valley wind in Urumqi City was most obvious at 850 hPa, according to the WRF model.

Understanding thermal circulations and near-surface turbulence processes in a small mountain valley

NASA Astrophysics Data System (ADS)

Pardyjak, E.; Dupuy, F.; Durand, P.; Gunawardena, N.; Thierry, H.; Roubin, P.

2017-12-01

The interaction of turbulence and thermal circulations in complex terrain can be significantly different from idealized flat terrain. In particular, near-surface horizontal spatial and temporal variability of winds and thermodynamic variables can be significant event over very small spatial scales. The KASCADE (KAtabatic winds and Stability over CAdarache for Dispersion of Effluents) 2017 conducted from January through March 2017 was designed to address these issues and to ultimately improve prediction of dispersion in complex terrain, particularly during stable atmospheric conditions. We have used a relatively large number of sensors to improve our understanding of the spatial and temporal development, evolution and breakdown of topographically driven flows. KASCADE 2017 consisted of continuous observations and fourteen Intensive Observation Periods (IOPs) conducted in the Cadarache Valley located in southeastern France. The Cadarache Valley is a relatively small valley (5 km x 1 km) with modest slopes and relatively small elevation differences between the valley floor and nearby hilltops ( 100 m). During winter, winds in the valley are light and stably stratified at night leading to thermal circulations as well as complex near-surface atmospheric layering. In this presentation we present results quantifying spatial variability of thermodynamic and turbulence variables as a function of different large -scale forcing conditions (e.g., quiescent conditions, strong westerly flow, and Mistral flow). In addition, we attempt to characterize highly-regular nocturnal horizontal wind meandering and associated turbulence statistics.

Boundary Layer Characterization during Perdigão Field Campaign 2017

NASA Astrophysics Data System (ADS)

Leo, L. S.; Salvadore, J. J.; Belo-Pereira, M.; Menke, R.; Gomes, S.; Krishnamurthy, R.; Brown, W. O. J.; Creegan, E.; Klein, P. M.; Wildmann, N.; Oncley, S.; Fernando, J.; Mann, J.

2017-12-01

The depth and structure of the atmospheric boundary layer (ABL) significantly impact the performances of wind farms located in complex terrain environments, since low-level jets and other flow structures in the proximity of hills and mountains determine the weather extremes, such as shear layer instabilities, lee/internal wave breaking, etc. which in turn profoundly modify the turbulence profile at wind turbine relevant heights.A suite of instruments was deployed covering a double-ridge in central Portugal near the town of Perdigão in 2016-2017, and they are used here to characterize the ABL structure over complex terrain during the Intensive Observational Period (IOP, May 1- June 15, 2017) of the research field program dubbed "Perdigão". Firstly, the methodology adopted in this work to estimate the BL height will be discussed; secondly, an overview of the BL depth and characteristics during Perdigão-IOP campaign will be provided, with emphasis on case studies of interest for both the wind-power and boundary-layer communities.

Volcanism in Northwest Ishtar Terra, Venus

NASA Astrophysics Data System (ADS)

Gaddis, Lisa R.; Greeley, Ronald

1990-10-01

Evidence is presented for a previously undocumented volcanic complex in the highlands of NW Ishtar Terra (74 deg N, 313 deg E). The proposed valcanic center is in mountainous banded terrain thought to have been formed by regional compression. Data used include Soviet Venera 15/16 radar images and topography (Fotokarta Veneri B-4, 1987). An attempt is made to assess the place of this feature in the framework of known volcanic landforms of the Lakshmi Planum and to examine the relationships between volcanism and tectonism in this region.

Evaluation of High Density Surface Observations in Complex Terrain and Their Contribution to the MM5 Model

DTIC Science & Technology

2007-03-01

westerly surface winds, the existence of a dry-adiabatic lapse rate, and often the appearance of wave cloud features (Oard, 1993). For a long time...indicate that a large-scale mountain wave feature was present across almost the entire western United States. The GFS indicates this was a standing 31... wave and not a propagating feature since it persisted with very little movement from about 0600 UTC 6 Mar until about 0000 UTC 7 Mar. A cross

Nowcasting in the FROST-2014 Sochi Olympic project

NASA Astrophysics Data System (ADS)

Bica, Benedikt; Wang, Yong; Joe, Paul; Isaac, George; Kiktev, Dmitry; Bocharnikov, Nikolai

2013-04-01

FROST (Forecast and Research: the Olympic Sochi Testbed) 2014 is a WMO WWRP international project aimed at development, implementation, and demonstration of capabilities of short-range numerical weather prediction and nowcasting technologies for mountainous terrain in winter season. Sharp weather contrasts and high spatial and temporal variability are typical for the region of the Sochi-2014 Olympics. Steep mountainous terrain and an intricate mixture of maritime sub-tropical and Alpine environments make weather forecasting in this region extremely challenging. Goals of the FROST-2014 project: • To develop a comprehensive information resource of Alpine winter weather observations; • To improve and exploit: o Nowcasting systems of high impact weather phenomena (precipitation type and intensity, snow levels, visibility, wind speed, direction and gusts) in complex terrain; o High-resolution deterministic and ensemble mesoscale forecasts in winter complex terrain environment; • To improve the understanding of physics of high impact weather phenomena in the region; • To deliver forecasts (Nowcasts) to Olympic weather forecasters and decision makers and assess benefits of forecast improvement. 46 Automatic Meteorological Stations (AMS) were installed in the Olympic region by Roshydromet, by owners of sport venues and by the Megafon corporation, provider of mobile communication services. The time resolution of AMS observations does not exceed 10 minutes. For a subset of the stations it is even equal to 1 min. Data flow from the new dual polarization Doppler weather radar WRM200 in Sochi was organized at the end of 2012. Temperature/humidity and wind profilers and two Micro Rain Radars (MRR) will supplement the network. Nowcasting potential of NWP models participating in the project (COSMO, GEM, WRF, AROME, HARMONIE) is to be assessed for direct and post-processed (e.g. Kalman filter, 1-D model, MOS) model forecasts. Besides the meso-scale models, the specialized nowcasting systems are expected to be used in the project - ABOM, CARDS, INCA, INTW, STEPS, MeteoExpert. FROST-2014 is intended as an 'end-to-end' project. Its products will be used by local forecasters for meteorological support of the Olympics and preceding test sport events. The project is open for new interested participants. Additional information is available at http://frost2014.meteoinfo.ru.

Analysing Surface Exposure to Climate Dynamics in the Himalayas to Adopt a Planning Framework for Landslide Risk Reduction

NASA Astrophysics Data System (ADS)

Tiwari, A.

2017-12-01

Himalayas rank first in the inventory of most densely populated and congested high altitude mountain regions of the planet. The region is mostly characterized by inadequate infrastructure, lack of mitigation tools along with constraints of terrain undermining the carrying capacity and resilience of urban ecosystems. Moreover, climate change has increased vulnerability of poor and marginalized population living in rapidly urbanizing mountain towns to increased frequency and severity of risks from extreme weather events. Such events pose multifold threat by easily translating to hazards, without the ability to respond and mitigate. Additionally, the recent extreme climate dynamics such as rainfall patterns have influenced the natural rate of surface/slope processes in the Himalaya. The aim of the study was to analyze the extent of interaction between climate dynamics and upland surface to develop participatory planning framework for landslide risk reduction using Integral Geographic Information System (integral GIS). At this stage, the study is limited to only rainfall triggered landslides (RTL). The study region lies in the middle Himalayan range (Himachal). Research utilized terrain analysis tools in integral GIS and identified risk susceptible surface without: 1.adding to its (often) complex fragmentation, and 2. Interference in surface/slope processes. Analysis covered most of the relevant surface factors including geology, slope instability, infrastructure development, natural and urban drainage system, land-cover and land-use as well. The outcome included an exposure-reduced model of existing terrain and the surface-process accommodated by it, with the use of local technical tools available among the poor and fragile mountain community. The final participatory planning framework successfully harmonized people's perception and adaptation knowledge, and incorporated priorities of local authorities. This research is significant as it rises above the fundamental challenges arising during management of the (often) conflicting perspectives, interests, and approaches of multiplicity of stakeholders thereby having vast potential to replicate/upscale in mountains beyond the study region as it ensures barrier free risk-communication through the most affordable and innovative tools.

Combat Operations in Mountainous Terrain: Are United States Army Light Infantry Divisions Preparing Properly?

DTIC Science & Technology

1987-06-05

Mountain Division, Charles Hauptman, Comeany I. 97th Mountain Infantry Regiment by CPT George Earle, and PFC Hugh Graves (1945), and 10th Mountain...training in this country is believed to depend primarily ’Albert H. Jackman , "The Tenth Mountain Division, A Successful Experiment," The Algine Journal...44-48. Houston, Charles S., Dr. "Altitude Sickness and the Army," 112zard. 2d Qtr 1986: n.p. Jackman , Albert H. "The Tenth Mountain Division, A

Performance of Precipitation Algorithms During IPHEx and Observations of Microphysical Characteristics in Complex Terrain

NASA Astrophysics Data System (ADS)

Erlingis, J. M.; Gourley, J. J.; Kirstetter, P.; Anagnostou, E. N.; Kalogiros, J. A.; Anagnostou, M.

2015-12-01

An Intensive Observation Period (IOP) for the Integrated Precipitation and Hydrology Experiment (IPHEx), part of NASA's Ground Validation campaign for the Global Precipitation Measurement Mission satellite took place from May-June 2014 in the Smoky Mountains of western North Carolina. The National Severe Storms Laboratory's mobile dual-pol X-band radar, NOXP, was deployed in the Pigeon River Basin during this time and employed various scanning strategies, including more than 1000 Range Height Indicator (RHI) scans in coordination with another radar and research aircraft. Rain gauges and disdrometers were also positioned within the basin to verify precipitation estimates and estimation of microphysical parameters. The performance of the SCOP-ME post-processing algorithm on NOXP data is compared with real-time and near real-time precipitation estimates with varying spatial resolutions and quality control measures (Stage IV gauge-corrected radar estimates, Multi-Radar/Multi-Sensor System Quantitative Precipitation Estimates, and CMORPH satellite estimates) to assess the utility of a gap-filling radar in complex terrain. Additionally, the RHI scans collected in this IOP provide a valuable opportunity to examine the evolution of microphysical characteristics of convective and stratiform precipitation as they impinge on terrain. To further the understanding of orographically enhanced precipitation, multiple storms for which RHI data are available are considered.

Accuracy of a high-resolution lidar terrain model under a conifer forest canopy

Treesearch

S.E. Reutebuch; R.J. McGaughey; H.-E. Andersen; W.W. Carson

2003-01-01

Airborne laser scanning systems can provide terrain elevation data for open areas with a vertical accuracy of 15 cm. In this study, a high-resolution digital terrain model (DTM) was produced from high-density lidar data. Vegetation in the 500-ha mountainous study area varied from bare ground to dense 70-year-old conifer forest. Conventional ground survey methods were...

Evaluation and parameterization of ATCOR3 topographic correction method for forest cover mapping in mountain areas

NASA Astrophysics Data System (ADS)

Balthazar, Vincent; Vanacker, Veerle; Lambin, Eric F.

2012-08-01

A topographic correction of optical remote sensing data is necessary to improve the quality of quantitative forest cover change analyses in mountainous terrain. The implementation of semi-empirical correction methods requires the calibration of model parameters that are empirically defined. This study develops a method to improve the performance of topographic corrections for forest cover change detection in mountainous terrain through an iterative tuning method of model parameters based on a systematic evaluation of the performance of the correction. The latter was based on: (i) the general matching of reflectances between sunlit and shaded slopes and (ii) the occurrence of abnormal reflectance values, qualified as statistical outliers, in very low illuminated areas. The method was tested on Landsat ETM+ data for rough (Ecuadorian Andes) and very rough mountainous terrain (Bhutan Himalayas). Compared to a reference level (no topographic correction), the ATCOR3 semi-empirical correction method resulted in a considerable reduction of dissimilarities between reflectance values of forested sites in different topographic orientations. Our results indicate that optimal parameter combinations are depending on the site, sun elevation and azimuth and spectral conditions. We demonstrate that the results of relatively simple topographic correction methods can be greatly improved through a feedback loop between parameter tuning and evaluation of the performance of the correction model.

Merging of an EET CInSAR DEM with the SRTM DEM

NASA Astrophysics Data System (ADS)

Wegmuller, Urs; Wiesmann, Andreas; Santoro, Maurizio

2010-03-01

Cross-interferometry (CInSAR) using ERS-2 and ENVISAT ASAR SAR data acquired in the ERS like mode IS2 at VV-polarization with perpendicular baselines of approximately 2 kilometers permits generation of digital elevation models (DEMs). Thanks to the long perpendicular baselines CInSAR has a good potential to generate accurate DEMs over relatively flat terrain. Over sloped terrain the topographic phase gradients get very high and the signals decorrelate if the carrier frequency difference and the baseline effects do not compensate any more. As a result phase unwrapping gets very difficult so that often no reliable solution is obtained for hilly terrain, resulting in DEMs with significant spatial gaps.Spatial gaps in ERS-2 ENVISAT Tandem (EET) CInSAR DEMs over hilly terrain are clearly an important limitation to the utility of these DEMs. On the other hand the high quality achieved over relatively flat terrain is of high interest. As an attempt to significantly improve the utility of the "good information" contained in the CInSAR DEM we developed a methodology to merge a CInSAR DEM with another available DEM, e.g. the SRTM DEM.The methodology was applied to an area in California, USA, including relatively flat terrain belonging to the Mohave desert as well as hilly to mountainous terrain of the San Gabriel and Tehachapi Mountains.

Estimating the probability of mountain pine beetle red-attack damage

Treesearch

Michael A Wulder; J. C. White; Barbara J Bentz; M. F. Alvarez; N. C. Coops

2006-01-01

Accurate spatial information on the location and extent of mountain pine beetle infestation is critical for the planning of mitigation and treatment activities. Areas of mixed forest and variable terrain present unique challenges for the detection and mapping of mountain pine beetle red-attack damage, as red-attack has a more heterogeneous distribution under these...

Distributed energy-balance modeling of snow-cover evolution and melt in rugged terrain: Tobacco Root Mountains, Montana, USA

USGS Publications Warehouse

Letsinger, S.L.; Olyphant, G.A.

2007-01-01

A distributed energy-balance model was developed for simulating snowpack evolution and melt in rugged terrain. The model, which was applied to a 43-km2 watershed in the Tobacco Root Mountains, Montana, USA, used measured ambient data from nearby weather stations to drive energy-balance calculations and to constrain the model of Liston and Sturm [Liston, G.E., Sturm, M., 1998. A snow-transport model for complex terrain. Journal of Glaciology 44 (148), 498-516] for calculating the initial snowpack thickness. Simulated initial snow-water equivalent ranged between 1 cm and 385 cm w.e. (water equivalent) with high values concentrated on east-facing slopes below tall summits. An interpreted satellite image of the snowcover distribution on May 6, 1998, closely matched the simulated distribution with the greatest discrepancy occurring in the floor of the main trunk valley. Model simulations indicated that snowmelt commenced early in the melt season, but rapid meltout of snow cover did not occur until after the average energy balance of the entire watershed became positive about 45 days into the melt season. Meltout was fastest in the lower part of the watershed where warmer temperatures and tree cover enhanced the energy income of the underlying snow. An interpreted satellite image of the snowcover distribution on July 9, 1998 compared favorably with the simulated distribution, and melt curves for modeled canopy-covered cells mimicked the trends measured at nearby snow pillow stations. By the end of the simulation period (August 3), 28% of the watershed remained snow covered, most of which was concentrated in the highest parts of the watershed where initially thick accumulations had been shaded by surrounding summits. The results of this study provide further demonstration of the critical role that topography plays in the timing and magnitude of snowmelt from high mountain watersheds. ?? 2006 Elsevier B.V. All rights reserved.

Evaluation of ERA-Interim precipitation data in complex terrain

NASA Astrophysics Data System (ADS)

Gao, Lu; Bernhardt, Matthias; Schulz, Karsten

2013-04-01

Precipitation controls a large variety of environmental processes, which is an essential input parameter for land surface models e.g. in hydrology, ecology and climatology. However, rain gauge networks provides the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. Reanalysis products (e.g. ERA-40 and NCEP-NCAR) as surrogate data are increasing applied in the past years. Although they are improving forward, previous studies showed that these products should be objectively evaluated due to their various uncertainties. In this study, we evaluated the precipitation data from ERA-Interim, which is a latest reanalysis product developed by ECMWF. ERA-Interim daily total precipitation are compared with high resolution gridded observation dataset (E-OBS) at 0.25°×0.25° grids for the period 1979-2010 over central Alps (45.5-48°N, 6.25-11.5°E). Wet or dry day is defined using different threshold values (0.5mm, 1mm, 5mm, 10mm and 20mm). The correspondence ratio (CR) is applied for frequency comparison, which is the ratio of days when precipitation occurs in both ERA-Interim and E-OBS dataset. The result shows that ERA-Interim captures precipitation occurrence very well with a range of CR from 0.80 to 0.97 for 0.5mm to 20mm thresholds. However, the bias of intensity increases with rising thresholds. Mean absolute error (MAE) varies between 4.5 mm day-1 and 9.5 mm day-1 in wet days for whole area. In term of mean annual cycle, ERA-Interim almost has the same standard deviation of the interannual variability of daily precipitation with E-OBS, 1.0 mm day-1. Significant wet biases happened in ERA-Interim throughout warm season (May to August) and dry biases in cold season (November to February). The spatial distribution of mean annual daily precipitation shows that ERA-Interim significant underestimates precipitation intensity in high mountains and northern flank of Alpine chain from November to March while pronounced overestimate in the southern flank of Alps. The poor topographical and flow related characteristic representation of ERA-Interim model is possibly responsible for the bias. Particularly, the mountain block effect of moisture is weak captured. The comparison demonstrates that ERA-Interim precipitation intensity needs bias correction for further alpine climate studies, although it reasonably captures precipitation frequency. This critical evaluation not only diagnosed the data quality of ERA-Interim, but also provided the evidence for reanalysis products downscaling and bias correction in complex terrain.

Integrating limnological characteristics of high mountain lakes into the landscape of a natural area

USGS Publications Warehouse

Larson, Gary L.; Wones, A.; McIntire, C.D.; Samora, B.

1994-01-01

A general conceptual watershed-lake model of the complex interactions among climatic conditions, watershed location and characteristics, lake morphology, and fish predation was used to evaluate limnological characteristics of high mountain lakes. Our main hypothesis was that decreasing elevation in mountainous terrain corresponds to an increase in diversity of watershed size and lake area, depth, temperature, nutrient concentrations, and productivity. A second hypothesis was that watershed location and aspect relative to climatic gradients within mountainous terrain influences the limnological characteristics of the lakes. We evaluated these hypotheses by examining watershed location, aspect and size; lake morphology; water quality; and phytoplankton and zooplankton community characteristics among high mountain forest and subalpine lakes in Mount Rainier National Park. Although many of the comparisons between all forest and subalpine lakes were statistically insignificant, the results revealed trends that were consistent with our hypotheses. The forest lake group included more lakes with larger watersheds, larger surface areas, greater depths, higher concentrations of nutrients, and higher algal biovolumes than did the group of subalpine lakes. Deep lakes, which were mostly of the forest lake type, exhibited thermal stratification and relatively high values of some of the water-quality variables near the lake bottoms. However, the highest near-surface water temperatures and phytoplankton densities and the taxonomic structures of the phytoplankton and zooplankton assemblages were more closely related to geographical location, which corresponded to a west-east climate gradient in the park, than to lake type. Some crustacean and rotifer taxa, however, were limited in distribution by lake type. Fish predation did not appear to play an important role in the structure of the crustacean zooplankton communities at the genus level with the exception of Mowich Lake, where crustacean taxa were absent from the zooplankton community. This was the only lake inhabited by a true zooplanktivourous species of fish.

OLYMPEX: A Global Precipitation Mission (GPM) Ground Validation Campaign on the Olympic Peninsula in the Pacific Northwest

NASA Astrophysics Data System (ADS)

McMurdie, L. A.; Houze, R.; Lundquist, J. D.; Mass, C.; Petersen, W. A.; Schwaller, M.

2014-12-01

The Global Precipitation Measurement (GPM) Mission was successfully launched at 1837 UTC 27 February 2014 with the first space-borne Ku/Ka band Dual Frequency Precipitation Radar and a passive microwave radiometer (channels ranging from 10-183 GHz). The primary objective of the Core satellite is to measure rain and snow globally, determine its 3D structure, and act as the calibration satellite for a constellation of GPM passive microwave satellites. In order to assess how remotely sensed precipitation can be applied to a range of data applications, ground validation (GV) field campaigns are crucial. As such, the Olympic Mountains Experiment (OLYMPEX) is planned for November 2015 - February 2016. The Olympic Peninsula in Washington State is an ideal location to conduct a GV campaign. It is situated within an active mid-latitude winter storm track and receives among the highest annual precipitation amounts in North America. In one compact area, the Olympic peninsula ranges from ocean to coast to land to mountains. It contains a permanent snowfield and numerous associated river basins. This unique venue will enable the field campaign to monitor both upstream precipitation characteristics and processes over the ocean and their modification over complex terrain. The scientific goals of the OLYMPEX field campaign include physical validation of satellite algorithms, precipitation mechanisms in complex terrain, hydrological applications, and modeling studies. In order to address these goals, a wide variety of existing and new observations are planned. These include surface observing networks of meteorological stations, rain and snow gauges, surface microphysical measurements, and snowpack surveys. Several radars will be deployed including the NASA S-Band dual-polarimetric and NASA Dual-Frequency Dual-Polarimetric Doppler radars, the Canadian x-band radar, and other mobile radars. Several instrumented aircraft are likely to participate such as the NASA DC-8 and the University of North Dakota Citation. The aircraft measurements will determine upstream thermodynamic and moisture conditions, sample particle types and sizes, and act as a proxy for the satellite itself. The ground-based measurements will test how well the satellite proxy measurements determine the rain and snow over complex terrain.

Airborne measurements of turbulent trace gas fluxes and analysis of eddy structure in the convective boundary layer over complex terrain

NASA Astrophysics Data System (ADS)

Hasel, M.; Kottmeier, Ch.; Corsmeier, U.; Wieser, A.

2005-03-01

Using the new high-frequency measurement equipment of the research aircraft DO 128, which is described in detail, turbulent vertical fluxes of ozone and nitric oxide have been calculated from data sampled during the ESCOMPTE program in the south of France. Based on airborne turbulence measurements, radiosonde data and surface energy balance measurements, the convective boundary layer (CBL) is examined under two different aspects. The analysis covers boundary-layer convection with respect to (i) the control of CBL depth by surface heating and synoptic scale influences, and (ii) the structure of convective plumes and their vertical transport of ozone and nitric oxides. The orographic structure of the terrain causes significant differences between planetary boundary layer (PBL) heights, which are found to exceed those of terrain height variations on average. A comparison of boundary-layer flux profiles as well as mean quantities over flat and complex terrain and also under different pollution situations and weather conditions shows relationships between vertical gradients and corresponding turbulent fluxes. Generally, NO x transports are directed upward independent of the terrain, since primary emission sources are located near the ground. For ozone, negative fluxes are common in the lower CBL in accordance with the deposition of O 3 at the surface. The detailed structure of thermals, which largely carry out vertical transports in the boundary layer, are examined with a conditional sampling technique. Updrafts mostly contain warm, moist and NO x loaded air, while the ozone transport by thermals alternates with the background ozone gradient. Evidence for handover processes of trace gases to the free atmosphere can be found in the case of existing gradients across the boundary-layer top. An analysis of the size of eddies suggests the possibility of some influence of the heterogeneous terrain in mountainous area on the length scales of eddies.

Technologies Render Views of Earth for Virtual Navigation

NASA Technical Reports Server (NTRS)

2012-01-01

On a December night in 1995, 159 passengers and crewmembers died when American Airlines Flight 965 flew into the side of a mountain while in route to Cali, Colombia. A key factor in the tragedy: The pilots had lost situational awareness in the dark, unfamiliar terrain. They had no idea the plane was approaching a mountain until the ground proximity warning system sounded an alarm only seconds before impact. The accident was of the kind most common at the time CFIT, or controlled flight into terrain says Trey Arthur, research aerospace engineer in the Crew Systems and Aviation Operations Branch at NASA s Langley Research Center. In situations such as bad weather, fog, or nighttime flights, pilots would rely on airspeed, altitude, and other readings to get an accurate sense of location. Miscalculations and rapidly changing conditions could contribute to a fully functioning, in-control airplane flying into the ground. To improve aviation safety by enhancing pilots situational awareness even in poor visibility, NASA began exploring the possibilities of synthetic vision creating a graphical display of the outside terrain on a screen inside the cockpit. How do you display a mountain in the cockpit? You have to have a graphics-powered computer, a terrain database you can render, and an accurate navigation solution, says Arthur. In the mid-1990s, developing GPS technology offered a means for determining an aircraft s position in space with high accuracy, Arthur explains. As the necessary technologies to enable synthetic vision emerged, NASA turned to an industry partner to develop the terrain graphical engine and database for creating the virtual rendering of the outside environment.

Mapping New Terrain: Climate Change and America's West. Report of the Consortium for Integrated Climate Research in Western Mountains (CIRMOUNT)

Treesearch

Henry F. CIRMOUNT Committee (Diaz; Constance I. Millar; Daniel R. Cayan; Michael D. Dettinger; Daniel B. Fagre; Lisa J. Graumlich; Greg Greenwood; Malcolm K. Hughes; David L. Peterson; Frank L. Powell; Kelly T. Redmond; Nathan L. Stephenson; Thomas W. Swetnam; Connie) Woodhouse

2006-01-01

Climate variability and sustained change presage far-reaching transformations across America’s West, an expanse dominated by immense mountain ranges and interspersed with important urban centers. These mountains provide the region’s life blood—water that courses through its streams and runs out its faucets, power that fuels its industries...

Volcanism in Northwest Ishtar Terra, Venus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaddis, L.R.; Greeley, R.

Evidence is presented for a previously undocumented volcanic complex in the highlands of NW Ishtar Terra (74 deg N, 313 deg E). The proposed valcanic center is in mountainous banded terrain thought to have been formed by regional compression. Data used include Soviet Venera 15/16 radar images and topography (Fotokarta Veneri B-4, 1987). An attempt is made to assess the place of this feature in the framework of known volcanic landforms of the Lakshmi Planum and to examine the relationships between volcanism and tectonism in this region. 38 refs.

Surface energy fluxes in complex terrain

NASA Technical Reports Server (NTRS)

Reiter, E. R.; Sheaffer, J. D.; Bossert, J. E.

1986-01-01

The emphasis of the 1985 NASA project activity was on field measurements of wind data and heat balance data. Initiatives included a 19 station mountaintop monitoring program, testing and refining the surface flux monitoring systems and packing and shipping equipment to the People's Republic of China in preparation for the 1986 Tibet Experiment. Other work included more extensive analyses of the 1984 Gobi Desert and Rocky Mountain observations plus some preliminary analyses of the 1985 mountaintop network data. Details of our field efforts are summarized and results of our data analyses are presented.

GIS for Predicting the Avalanche Zones in the Mountain Regions of Kazakhstan

NASA Astrophysics Data System (ADS)

Omirzhanova, Zh. T.; Urazaliev, A. S.; Aimenov, A. T.

2015-10-01

Foothills of Trans Ili Alatau is a recreational area with buildings and sports facilities and resorts, sanatoriums, etc. In summer and winter there are a very large number of skiers, climbers, tourists and workers of organizations which located in the mountains. In this regard, forecasting natural destructive phenomena using GIS software is an important task of many scientific fields. The formation of avalanches, except meteorological conditions, such as temperature, wind speed, snow thickness, especially affecting mountainous terrain. Great importance in the formation of avalanches play steepness (slope) of the slope and exposure. If steep slopes contribute to the accumulation of snow in some places, increase the risk of flooding of the slope, the various irregularities can delay an avalanche. According to statistics, the bulk of the avalanche is formed on the slopes steeper than 30°. In the course of research a 3D model of the terrain was created with the help of programs ArcGIS and Surfer. Identified areas with steep slopes, the exposure is made to the cardinal. For dangerous terrain location is divided into three groups: favorable zone, danger zone and the zone of increased risk. The range of deviations from 30-45° is dangerous, since the angle of inclination of more than 30°, there is a maximum thickness of sliding snow, water, the upper layer of the surface and there is an increase rate of moving array, and the mountain slopes at an angle 450 above are the area increased risk. Created on DTM data are also plotted Weather Service for the winter of current year. The resulting model allows to get information upon request and display it on map base, assess the condition of the terrain by avalanches, as well as to solve the problem of life safety in mountainous areas, to develop measures to prevent emergency situations and prevent human losses.

Airborne Lidar-Based Estimates of Tropical Forest Structure in Complex Terrain: Opportunities and Trade-Offs for REDD+

NASA Technical Reports Server (NTRS)

Leitold, Veronika; Keller, Michael; Morton, Douglas C.; Cook, Bruce D.; Shimabukuro, Yosio E.

2015-01-01

Background: Carbon stocks and fluxes in tropical forests remain large sources of uncertainty in the global carbon budget. Airborne lidar remote sensing is a powerful tool for estimating aboveground biomass, provided that lidar measurements penetrate dense forest vegetation to generate accurate estimates of surface topography and canopy heights. Tropical forest areas with complex topography present a challenge for lidar remote sensing. Results: We compared digital terrain models (DTM) derived from airborne lidar data from a mountainous region of the Atlantic Forest in Brazil to 35 ground control points measured with survey grade GNSS receivers. The terrain model generated from full-density (approx. 20 returns/sq m) data was highly accurate (mean signed error of 0.19 +/-0.97 m), while those derived from reduced-density datasets (8/sq m, 4/sq m, 2/sq m and 1/sq m) were increasingly less accurate. Canopy heights calculated from reduced-density lidar data declined as data density decreased due to the inability to accurately model the terrain surface. For lidar return densities below 4/sq m, the bias in height estimates translated into errors of 80-125 Mg/ha in predicted aboveground biomass. Conclusions: Given the growing emphasis on the use of airborne lidar for forest management, carbon monitoring, and conservation efforts, the results of this study highlight the importance of careful survey planning and consistent sampling for accurate quantification of aboveground biomass stocks and dynamics. Approaches that rely primarily on canopy height to estimate aboveground biomass are sensitive to DTM errors from variability in lidar sampling density.

Airborne lidar-based estimates of tropical forest structure in complex terrain: opportunities and trade-offs for REDD+

PubMed

Leitold, Veronika; Keller, Michael; Morton, Douglas C; Cook, Bruce D; Shimabukuro, Yosio E

2015-12-01

Carbon stocks and fluxes in tropical forests remain large sources of uncertainty in the global carbon budget. Airborne lidar remote sensing is a powerful tool for estimating aboveground biomass, provided that lidar measurements penetrate dense forest vegetation to generate accurate estimates of surface topography and canopy heights. Tropical forest areas with complex topography present a challenge for lidar remote sensing. We compared digital terrain models (DTM) derived from airborne lidar data from a mountainous region of the Atlantic Forest in Brazil to 35 ground control points measured with survey grade GNSS receivers. The terrain model generated from full-density (~20 returns m -2 ) data was highly accurate (mean signed error of 0.19 ± 0.97 m), while those derived from reduced-density datasets (8 m -2 , 4 m -2 , 2 m -2 and 1 m -2 ) were increasingly less accurate. Canopy heights calculated from reduced-density lidar data declined as data density decreased due to the inability to accurately model the terrain surface. For lidar return densities below 4 m -2 , the bias in height estimates translated into errors of 80-125 Mg ha -1 in predicted aboveground biomass. Given the growing emphasis on the use of airborne lidar for forest management, carbon monitoring, and conservation efforts, the results of this study highlight the importance of careful survey planning and consistent sampling for accurate quantification of aboveground biomass stocks and dynamics. Approaches that rely primarily on canopy height to estimate aboveground biomass are sensitive to DTM errors from variability in lidar sampling density.

Observational study of surface wind along a sloping surface over mountainous terrain during winter

NASA Astrophysics Data System (ADS)

Lee, Young-Hee; Lee, Gyuwon; Joo, Sangwon; Ahn, Kwang-Deuk

2018-03-01

The 2018 Winter Olympic and Paralympic Games will be held in Pyeongchang, Korea, during February and March. We examined the near surface winds and wind gusts along the sloping surface at two outdoor venues in Pyeongchang during February and March using surface wind data. The outdoor venues are located in a complex, mountainous terrain, and hence the near-surface winds form intricate patterns due to the interplay between large-scale and locally forced winds. During February and March, the dominant wind at the ridge level is westerly; however, a significant wind direction change is observed along the sloping surface at the venues. The winds on the sloping surface are also influenced by thermal forcing, showing increased upslope flow during daytime. When neutral air flows over the hill, the windward and leeward flows show a significantly different behavior. A higher correlation of the wind speed between upper- and lower-level stations is shown in the windward region compared with the leeward region. The strong synoptic wind, small width of the ridge, and steep leeward ridge slope angle provide favorable conditions for flow separation at the leeward foot of the ridge. The gust factor increases with decreasing surface elevation and is larger during daytime than nighttime. A significantly large gust factor is also observed in the leeward region.

Quantifying geological structures of the Nigde province in central Anatolia, Turkey using SRTM DEM data

NASA Astrophysics Data System (ADS)

Demirkesen, A. C.

2009-01-01

A digital terrain model and a 3D fly-through model of the Nigde province in central Anatolia, Turkey were generated and quantitatively analyzed employing the shuttle radar topographic mission (SRTM) digital elevation model (DEM). Besides, stream drainage patterns, lineaments and structural-geological features were extracted and analyzed. In the process of analyzing and interpreting the DEM for landforms, criteria such as color and color tones (attributes of heights), topography (shaded DEM and 3D fly-through model) and stream drainage patterns were employed to acquire geo-information about the land, such as hydrologic, geomorphologic, topographic and tectonic structures. In this study, the SRTM DEM data of the study region were experimentally used for both DEM classification and quantitative analysis of the digital terrain model. The results of the DEM classification are: (1) low plain including the plains of Bor and Altunhisar (20.7%); (2) high plain including the Misli (Konakli) plain (28.8%); (3) plateau plain including the Melendiz (Ciftlik) plateau plain (1.0%); (4) mountain including the Nigde massif (33.3%); and (5) high mountain (16.2%). High mountain areas include a caldera complex of Mt Melendiz, Mt Hasan and Mt Pozanti apart from the Ala mountains called Aladaglar and the Bolkar mountains called Bolkarlar in the study region (7,312 km2). Analysis of both the stream drainage patterns and the lineaments revealed that the Nigde province has a valley zone called Karasu valley zone (KVZ) or Nigde valley zone (NVZ), where settlements and agricultural plains, particularly the Bor plain in addition to settlements of the Bor town and the central city of Nigde have the most flooding risk when a heavy raining occurs. The study revealed that the NVZ diagonally divides the study region roughly into two equal parts, heading from northeast to southwest. According to the map created in this study, the right side of the NVZ has more mountainous area, where the Aladaglar is a wildlife national park consisting of many species of fauna and flora whereas the left side of the NVZ has more agricultural plain, with exception of a caldera complex of Mt Melendiz and volcanic Mt Hasan. The south of the study region includes the Bolkarlar. In addition, the Ecemis fault zone (EFZ) lying along the Ecemis rivulet, running from north to south at the west side of the Aladaglar, forms the most important and sensitive location in the region in terms of the tectonics.

How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change? (Invited)

NASA Astrophysics Data System (ADS)

Bond, B. J.; Peterson, K.; McKane, R.; Lajtha, K.; Quandt, D. J.; Allen, S. T.; Sell, S.; Daly, C.; Harmon, M. E.; Johnson, S. L.; Spies, T.; Sollins, P.; Abdelnour, A. G.; Stieglitz, M.

2010-12-01

We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site situated in Oregon’s central-western Cascade Range. Decades of long-term measurements and intensive research have revealed influences of topography on vegetation patterns, disturbance history, and hydrology. More recent research has shown surprising interactions between microclimates and synoptic weather patterns due to cold air drainage and pooling in mountain valleys. Using these data and insights, in addition to a recent LiDAR (Light Detection and Ranging) reconnaissance and a small sensor network, we are employing process-based models, including “SPA” (Soil-Plant-Atmosphere, developed by Mathew Williams of the University of Edinburgh), and “VELMA” (Visualizing Ecosystems for Land Management Alternatives, developed by Marc Stieglitz and colleagues of the Georgia Institute of Technology) to focus on two important features of mountainous landscapes: heterogeneity (both spatial and temporal) and connectivity (atmosphere-canopy-hillslope-stream). Our research questions include: 1) Do fine-scale spatial and temporal heterogeneity result in emergent properties at the basin scale, and if so, what are they? 2) How does connectivity across ecosystem components affect system responses to climate variability and change? Initial results show that for environmental drivers that elicit non-linear ecosystem responses on the plot scale, such as solar radiation, soil depth and soil water content, fine-scale spatial heterogeneity may produce unexpected emergent properties at larger scales. The results from such modeling experiments are necessarily a function of the supporting algorithms. However, comparisons based on models such as SPA and VELMA that operate at much different spatial scales (plots vs. hillslopes) and levels of biophysical organization (individual plants vs. aggregate plant biomass) can help us to understand how and why mountainous ecosystems may have distinctive responses to climate variability and climate change.

A contrast between nocturnal flow regimes: Observations and modeling simulations of katabatic intrusions in the Laramie Valley

NASA Astrophysics Data System (ADS)

Juliano, Timothy W.

Katabatic winds commonly occur in mountainous regions under statically stable conditions when a sufficient deficit exists in the net radiation budget. Observations of these stable boundary layer (SBL) downslope flows have extended back to the 1930s. Their interactions with other SBL processes, including cold air pools (CAPs) and mountain waves, are quite complex, however, and have only more recently been deeply investigated. The University of Wyoming (UW) wind tower (WT) and flux tower (WT), situated in the Laramie Valley, were utilized in examining a dataset spanning from 14 December 2011 to 12 September 2013. A set of criteria were developed to determine katabatic intrusion events, and establish a climatology of these events, at the WT. The 21-22 December 2012 nighttime period was then studied in detail using data from the aforementioned towers in addition to weather stations throughout the Laramie Valley and the Weather Research and Forecasting (WRF) model. Both observations and modeling results indicated a competition between two strongly contrasting flow regimes: synoptic and katabatic. The synoptic regime was characterized by strong, southwesterly winds, warm temperatures, and turbulent flow, while the katabatic regime featured weaker, southeasterly winds, cooler temperatures, and intermittently turbulent flow. Sonic and propeller anemometers on the WT elucidated the chaotic transition between the regimes. At the WT, it was found that between regimes the wind speed decreased by up to 60%, wind direction often shifted over 120°, and potential temperature usually decreased more than 2°C. The katabatic wind depth was postulated to be variable in time and space, with its head sloping towards the trailing CAP. Topographically generated mountain waves and local terrain forcing are suspected to play an integral role in the development and evolution of the katabatic wind in the Laramie Valley. Results from this research yield promising insight into the intricate relationships between various SBL processes in complex terrain.

A comparison of near-surface potential temperature variance budgets for unstable atmospheric flows over vegetated and non-vegetated flat surfaces and a gentle slope

NASA Astrophysics Data System (ADS)

Hang, C.; Nadeau, D.; Pardyjak, E.; Parlange, M. B.

2017-12-01

Over the past decades, researchers have made much progress toward a fundamental understanding of the budgets of turbulence variables over flat and homogeneous terrain, and only more recently over complex terrain. However, temperature variance budgets, which are parameterized in most meteorological models, are still poorly understood even under relatively idealized conditions. In this work, we rely on near-surface turbulence observations collected as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. Data collected in May 2013 in western Utah at three field sites subjected to similar large-scale forcing are analyzed: a desert playa (dry lakebed), characterized by a at surface devoid of vegetation; a vegetated site, characterized by at valley oor covered with greasewood vegetation, and a mountain terrain site with a slope angle of 2 -4° and covered by high-elevation vegetation. The analysis reveals the presence of a 5-m layer where the production and dissipation terms of potential temperature variance (θ2) drop rapidly below this level. During convective periods, vertical advection and turbulent transport of θ2 can often be non-negligible, in particular at Playa and Slope sites. In addition, within the 5-m layer, turbulent transport of θ2 acts as a sink term at all sites of interest. Neither the ratio of turbulent transport to production nor the ratio of production to dissipation show a stability dependence during the unstable periods studied. A short-period comparison of dissipation rates calculated using dissipation-scale resolving hot-wire/cold-wire anemometry and several common indirect methods using sonic anemometry is presented for data acquired at Playa site. The results indicates that the dissipation rates from all methods follow similar trends, however the magnitudes can differ by a factor of 2 - 3.

The Mesoscale Predictability of Terrain Induced Flows

DTIC Science & Technology

2009-09-30

simulations, we focus on assessing the predictability of winds, mountain waves and clear air turbulence ( CAT ) in the lee of the Sierra Nevada...complete description of the sensitivity of mountain waves, CAT and downslope to small variations in the initial conditions. WORK COMPLETED We...completed the analysis of the sensitivity of mountain waves, CAT and downslope winds to small perturbations in the upstream conditions. We also

Holocene erosion, sedimentation, and stratigraphy at Raven Fork, Southern Blue Ridge Mountains, USA

Treesearch

David S. Leigh; Paul A. Webb

2006-01-01

Holocene colluvial and alluvial stratigraphy and a radiocarbon chronology are presented for the valley of the lower three kilometers of Raven Fork, a mountain stream draining 194 km2 of high relief (1.3 km) terrain of the Southern Blue Ridge Mountains in western North Carolina, USA, which is in a region that lacks good chronological data. Lower hillslopes, alluvial/...

Development of a photo guide for fuels in the Southern Appalachian Mountains of Northeast Georgia and Western South Carolina

Treesearch

Sandra Rideout-Hanzak; Lucy Brudnak; Thomas A. Waldrop

2006-01-01

Current methods of assessing the characteristics of forest fuels are time-consuming, expensive, and impractical in the mountainous terrain of the southeastern United States. A photo guide to fuels is being developed. It will be a quick, inexpensive, and easy-to-use tool for various management applications in the Southern Appalachian Mountains. Fuels data and photos...

Aircraft accident report : uncontrolled flight into terrain, ABX Air (Airborne Express), Douglas DC-8-63, N827AX Narrows, Virginia, December 22, 1996

DOT National Transportation Integrated Search

1997-07-15

This report explains the accident involving a Douglas DC-8-63, operated by ABX Air Inc. (Airborne Express), that impacted mountainous terrain near Narrows, Virginia, while on a post-modification functional evaluation flight on December 22, 1996. Safe...

75 FR 71414 - Questa Ranger District, Carson National Forest; Taos County, NM; Taos Ski Valley's 2010 Master...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-23

... Development Plan (MDP). These proposed projects include: Adding new lifts to serve terrain that is currently only accessible by hiking; replacing old lifts; creating new gladed terrain; improving traffic... (snowtubing and snowshoeing trails); and a lift-served mountain biking trail. All proposed projects are within...

76 FR 60451 - Questa Ranger District, Carson National Forest; Taos County, NM; Taos Ski Valley's 2010 Master...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-29

... (TSV) 2010 Master Development Plan (MDP). The proposed projects include: Adding new lifts to serve terrain that is currently only accessible by hiking; replacing old lifts; creating new gladed terrain... Adventure Center (snowtubing and snowshoeing trails); and developing a lift-served mountain biking trail...

Comparison of methods for quantifying surface sublimation over seasonally snow-covered terrain

USGS Publications Warehouse

Sexstone, Graham A.; Clow, David W.; Stannard, David I.; Fassnacht, Steven R.

2016-01-01

Snow sublimation can be an important component of the snow-cover mass balance, and there is considerable interest in quantifying the role of this process within the water and energy balance of snow-covered regions. In recent years, robust eddy covariance (EC) instrumentation has been used to quantify snow sublimation over snow-covered surfaces in complex mountainous terrain. However, EC can be challenging for monitoring turbulent fluxes in snow-covered environments because of intensive data, power, and fetch requirements, and alternative methods of estimating snow sublimation are often relied upon. To evaluate the relative merits of methods for quantifying surface sublimation, fluxes calculated by the EC, Bowen ratio–energy balance (BR), bulk aerodynamic flux (BF), and aerodynamic profile (AP) methods and their associated uncertainty were compared at two forested openings in the Colorado Rocky Mountains. Biases between methods are evaluated over a range of environmental conditions, and limitations of each method are discussed. Mean surface sublimation rates from both sites ranged from 0.33 to 0.36 mm day−1, 0.14 to 0.37 mm day−1, 0.10 to 0.17 mm day−1, and 0.03 to 0.10 mm day−1 for the EC, BR, BF and AP methods, respectively. The EC and/or BF methods are concluded to be superior for estimating surface sublimation in snow-covered forested openings. The surface sublimation rates quantified in this study are generally smaller in magnitude compared with previously published studies in this region and help to refine sublimation estimates for forested openings in the Colorado Rocky Mountains.

Ecosystem function in complex mountain terrain: Combining models and long-term observations to advance process-based understanding

NASA Astrophysics Data System (ADS)

Wieder, William R.; Knowles, John F.; Blanken, Peter D.; Swenson, Sean C.; Suding, Katharine N.

2017-04-01

Abiotic factors structure plant community composition and ecosystem function across many different spatial scales. Often, such variation is considered at regional or global scales, but here we ask whether ecosystem-scale simulations can be used to better understand landscape-level variation that might be particularly important in complex terrain, such as high-elevation mountains. We performed ecosystem-scale simulations by using the Community Land Model (CLM) version 4.5 to better understand how the increased length of growing seasons may impact carbon, water, and energy fluxes in an alpine tundra landscape. The model was forced with meteorological data and validated with observations from the Niwot Ridge Long Term Ecological Research Program site. Our results demonstrate that CLM is capable of reproducing the observed carbon, water, and energy fluxes for discrete vegetation patches across this heterogeneous ecosystem. We subsequently accelerated snowmelt and increased spring and summer air temperatures in order to simulate potential effects of climate change in this region. We found that vegetation communities that were characterized by different snow accumulation dynamics showed divergent biogeochemical responses to a longer growing season. Contrary to expectations, wet meadow ecosystems showed the strongest decreases in plant productivity under extended summer scenarios because of disruptions in hydrologic connectivity. These findings illustrate how Earth system models such as CLM can be used to generate testable hypotheses about the shifting nature of energy, water, and nutrient limitations across space and through time in heterogeneous landscapes; these hypotheses may ultimately guide further experimental work and model development.

Analysis of the long-term surface wind variability over complex terrain using a high spatial resolution WRF simulation

NASA Astrophysics Data System (ADS)

Jiménez, Pedro A.; González-Rouco, J. Fidel; Montávez, Juan P.; García-Bustamante, E.; Navarro, J.; Dudhia, J.

2013-04-01

This work uses a WRF numerical simulation from 1960 to 2005 performed at a high horizontal resolution (2 km) to analyze the surface wind variability over a complex terrain region located in northern Iberia. A shorter slice of this simulation has been used in a previous study to demonstrate the ability of the WRF model in reproducing the observed wind variability during the period 1992-2005. Learning from that validation exercise, the extended simulation is herein used to inspect the wind behavior where and when observations are not available and to determine the main synoptic mechanisms responsible for the surface wind variability. A principal component analysis was applied to the daily mean wind. Two principal modes of variation accumulate a large percentage of the wind variability (83.7%). The first mode reflects the channeling of the flow between the large mountain systems in northern Iberia modulated by the smaller topographic features of the region. The second mode further contributes to stress the differentiated wind behavior over the mountains and valleys. Both modes show significant contributions at the higher frequencies during the whole analyzed period, with different contributions at lower frequencies during the different decades. A strong relationship was found between these two modes and the zonal and meridional large scale pressure gradients over the area. This relationship is described in the context of the influence of standard circulation modes relevant in the European region like the North Atlantic Oscillation, the East Atlantic pattern, East Atlantic/Western Russia pattern, and the Scandinavian pattern.

San Antonio Mountain Experiment (SAMEX).

NASA Astrophysics Data System (ADS)

McCutchan, Morris H.; Fox, Douglas G.; Furman, R. William

1982-10-01

The San Antonio Mountain Experiment (SAMEX) involves a 3325 m. conically shaped, isolated mountain in north-central New Mexico where hourly observations of temperature, relative humidity, wind speed, wind direction, and precipitation are being taken at nine locations over a three- to five-year period that began in 1980. The experiment is designed to isolate the effect of topography on these meteorological variables by using a geometric configuration sufficiently simple to lead to generalized results. One remote automatic weather station (RAWS) is located at the peak (3322 m); four are located at midslope (3033 m) on southwest, southeast, northeast, and northwest aspects; and four are at the base (2743 m) on southwest, southeast, northeast, and northwest aspects. The surface observations are supplemented by rawinsonde, pibal, tethersonde, and constant-level balloon observations at selected times during each year. The unique set of meteorological data collected in the experiment will be used to 1) determine the effect of elevation and aspect on the meteorological variables; 2) compare the temperature, humidity, and wind components on the mountain with observations and/or predictions of these variables in the free air nearby; and 3) validate temperature, humidity, and wind models in complex terrain.

MTCLIM: a mountain microclimate simulation model

Treesearch

Roger D. Hungerford; Ramakrishna R. Nemani; Steven W. Running; Joseph C. Coughlan

1989-01-01

A model for calculating daily microclimate conditions in mountainous terrain is presented. Daily air temperature, shortwave radiation, relative humidity, and precipitation are extrapolated form data measured at National Weather Service stations. The model equations are given and the paper describes how to execute the model. Model outputs are compared with observed data...

Scaling issues and spatio-temporal variability in ecohydrological modeling on mountain topography: Methods for improving the VELMA model

EPA Science Inventory

The interactions between vegetation and hydrology in mountainous terrain are difficult to represent in mathematical models. There are at least three primary reasons for this difficulty. First, expanding plot-scale measurements to the watershed scale requires finding the balance...

Mountainous terrain and violent conflict in the post-Soviet Caucasus.

NASA Astrophysics Data System (ADS)

Witmer, F. D. W.; Linke, A. M.; Holland, E.; O'Loughlin, J.

2015-12-01

What are the connections between mountainous terrain and violent conflict in the post-Soviet Caucasus? Political science and international relations research often use simplistic metrics to characterize terrain and its relation to conflict. We examine linkages between environmental conditions and conflict using fine-resolution spatially disaggregated data for violent events occurring in five wars in the broader Caucasus region: between the Russian state and separatists in Chechnya and the neighboring republics (1999-2002); the Russian state and Islamists in the North Caucasus (2002-2015); between Armenians and Azerbaijanis in Nagorno-Karabakh (1990-2015); and between Georgia and separatists in South Ossetia (1991-2008) and Abkhazia (1992-2008). For environmental conditions, we consider land use, elevation, and slope to identify profiles of violence intensity within each of the five cases. Data include forest cover derived from Landsat imagery, slope data calculated from a digital elevation model, and land cover derived from MODIS imagery. The Landsat imagery provide consistent 30 meter information on percent forest cover across the multiple study regions. We use GIS (buffers around conflict points) to create categorical summary statistics. The "operational costs of context" vary dramatically across regions within the study area and by the actor who initiates subsets of violent events. Our empirical focus is on Russia's south and the neighboring countries of the South Caucasus but we leverage comparisons between the five wars to generalize outward to other world regions and to contribute to research on conflict propensity in regions of rugged and mountainous terrain.

Watershed challenges for the 21st Century: A global perspective for mountainous terrain

Treesearch

Roy C. Sidle

2000-01-01

Three global challenges for watershed researchers in the 21st century are examined in this paper. These challenges are obtaining better assessments of terrain stability; understanding hydrologic responses at different watershed scales; and developing better methods for analyzing and assessing cumulative watershed effects. These topics are only a subset of the pressing...

Evaluating Precipitation Observed in Complex Terrain During GPM Field Campaigns with the SIMBA Data-Fusion Tool

NASA Astrophysics Data System (ADS)

Wingo, S. M.; Petersen, W. A.; Gatlin, P. N.; Marks, D. A.; Wolff, D. B.; Pabla, C. S.

2017-12-01

The versatile SIMBA (System for Integrating Multi-platform data to Build the Atmospheric column) precipitation data-fusion framework produces an atmospheric column data product with multi-platform observations set into a common 3-D grid, affording an efficient starting point for multi-sensor comparisons and analysis that can be applied to any region. Supported data sources include: ground-based scanning and profiling radars (S-, X-, Ku-, K-, and Ka-band), multiple types of disdrometers and rain gauges, the GPM Core Observatory's Microwave Imager (GMI, 10-183 GHz) and Dual-frequency Precipitation Radar (DPR, Ka/Ku-band), as well as thermodynamic soundings and the Multi-Radar/Multi-Sensor QPE product. SIMBA column data files provide a unique way to evaluate the complete vertical profile of precipitation. Two post-launch (GPM Core in orbit) field campaigns focused on different facets of the GPM mission: the Olympic Mountains Experiment (OLYMPEX) was geared toward winter season (November-February) precipitation in Pacific frontal systems and their transition from the coastal to mountainous terrain of northwest Washington, while the Integrated Precipitation and Hydrology Experiment (IPHEx) sampled warm season (April-June) precipitation and supported hydrologic applications in the southern Appalachians and eastern North Carolina. Both campaigns included multiple orographic precipitation enhancement episodes. SIMBA column products generated for select OLYMPEX and IPHEx events will be used to evaluate spatial variability and vertical profiles of precipitation and drop size distribution parameters derived and/or observed by space- and ground-based sensors. Results will provide a cursory view of how well the space-based measurements represent what is observed from the ground below and an indication to how the terrain in both regions impacts the characteristics of precipitation within the column and reaching the ground.

Evaluating Precipitation Observed in Complex Terrain During GPM Field Campaigns with the SIMBA Data-Fusion Tool

NASA Astrophysics Data System (ADS)

Wingo, S. M.; Petersen, W. A.; Gatlin, P. N.; Marks, D. A.; Wolff, D. B.; Pabla, C. S.

2016-12-01

The versatile SIMBA (System for Integrating Multi-platform data to Build the Atmospheric column) precipitation data-fusion framework produces an atmospheric column data product with multi-platform observations set into a common 3-D grid, affording an efficient starting point for multi-sensor comparisons and analysis that can be applied to any region. Supported data sources include: ground-based scanning and profiling radars (S-, X-, Ku-, K-, and Ka-band), multiple types of disdrometers and rain gauges, the GPM Core Observatory's Microwave Imager (GMI, 10-183 GHz) and Dual-frequency Precipitation Radar (DPR, Ka/Ku-band), as well as thermodynamic soundings and the Multi-Radar/Multi-Sensor QPE product. SIMBA column data files provide a unique way to evaluate the complete vertical profile of precipitation. Two post-launch (GPM Core in orbit) field campaigns focused on different facets of the GPM mission: the Olympic Mountains Experiment (OLYMPEX) was geared toward winter season (November-February) precipitation in Pacific frontal systems and their transition from the coastal to mountainous terrain of northwest Washington, while the Integrated Precipitation and Hydrology Experiment (IPHEx) sampled warm season (April-June) precipitation and supported hydrologic applications in the southern Appalachians and eastern North Carolina. Both campaigns included multiple orographic precipitation enhancement episodes. SIMBA column products generated for select OLYMPEX and IPHEx events will be used to evaluate spatial variability and vertical profiles of precipitation and drop size distribution parameters derived and/or observed by space- and ground-based sensors. Results will provide a cursory view of how well the space-based measurements represent what is observed from the ground below and an indication to how the terrain in both regions impacts the characteristics of precipitation within the column and reaching the ground.

Using noble gas tracers to constrain a groundwater flow model with recharge elevations: A novel approach for mountainous terrain

USGS Publications Warehouse

Doyle, Jessica M.; Gleeson, Tom; Manning, Andrew H.; Mayer, K. Ulrich

2015-01-01

Environmental tracers provide information on groundwater age, recharge conditions, and flow processes which can be helpful for evaluating groundwater sustainability and vulnerability. Dissolved noble gas data have proven particularly useful in mountainous terrain because they can be used to determine recharge elevation. However, tracer-derived recharge elevations have not been utilized as calibration targets for numerical groundwater flow models. Herein, we constrain and calibrate a regional groundwater flow model with noble-gas-derived recharge elevations for the first time. Tritium and noble gas tracer results improved the site conceptual model by identifying a previously uncertain contribution of mountain block recharge from the Coast Mountains to an alluvial coastal aquifer in humid southwestern British Columbia. The revised conceptual model was integrated into a three-dimensional numerical groundwater flow model and calibrated to hydraulic head data in addition to recharge elevations estimated from noble gas recharge temperatures. Recharge elevations proved to be imperative for constraining hydraulic conductivity, recharge location, and bedrock geometry, and thus minimizing model nonuniqueness. Results indicate that 45% of recharge to the aquifer is mountain block recharge. A similar match between measured and modeled heads was achieved in a second numerical model that excludes the mountain block (no mountain block recharge), demonstrating that hydraulic head data alone are incapable of quantifying mountain block recharge. This result has significant implications for understanding and managing source water protection in recharge areas, potential effects of climate change, the overall water budget, and ultimately ensuring groundwater sustainability.

An Efficient Ray-Tracing Method for Determining Terrain Intercepts in EDL Simulations

NASA Technical Reports Server (NTRS)

Shidner, Jeremy D.

2016-01-01

The calculation of a ray's intercept from an arbitrary point in space to a prescribed surface is a common task in computer simulations. The arbitrary point often represents an object that is moving according to the simulation, while the prescribed surface is fixed in a defined frame. For detailed simulations, this surface becomes complex, taking the form of real-world objects such as mountains, craters or valleys which require more advanced methods to accurately calculate a ray's intercept location. Incorporation of these complex surfaces has commonly been implemented in graphics systems that utilize highly optimized graphics processing units to analyze such features. This paper proposes a simplified method that does not require computationally intensive graphics solutions, but rather an optimized ray-tracing method for an assumed terrain dataset. This approach was developed for the Mars Science Laboratory mission which landed on the complex terrain of Gale Crater. First, this paper begins with a discussion of the simulation used to implement the model and the applicability of finding surface intercepts with respect to atmosphere modeling, altitude determination, radar modeling, and contact forces influencing vehicle dynamics. Next, the derivation and assumptions of the intercept finding method are presented. Key assumptions are noted making the routines specific to only certain types of surface data sets that are equidistantly spaced in longitude and latitude. The derivation of the method relies on ray-tracing, requiring discussion on the formulation of the ray with respect to the terrain datasets. Further discussion includes techniques for ray initialization in order to optimize the intercept search. Then, the model implementation for various new applications in the simulation are demonstrated. Finally, a validation of the accuracy is presented along with the corresponding data sets used in the validation. A performance summary of the method will be shown using the analysis from the Mars Science Laboratory's terminal descent sensing model. Alternate uses will also be shown for determining horizon maps and orbiter set times.

Mountain Biking with Groups: A "Safe" Activity?

ERIC Educational Resources Information Center

Allen, Terry

2001-01-01

A survey mailed to 200 British mountain bike leaders found that rates of cycling accidents and injuries were greater in forests and woodlands than on terrain where a license is required to lead groups of young cyclists. Excessive speed was mentioned in most accidents, coupled with poor use of breaks in many cases. (SV)

A Citizen Science Campaign to Validate Snow Remote-Sensing Products

NASA Astrophysics Data System (ADS)

Wikstrom Jones, K.; Wolken, G. J.; Arendt, A. A.; Hill, D. F.; Crumley, R. L.; Setiawan, L.; Markle, B.

2017-12-01

The ability to quantify seasonal water retention and storage in mountain snow packs has implications for an array of important topics, including ecosystem function, water resources, hazard mitigation, validation of remote sensing products, climate modeling, and the economy. Runoff simulation models, which typically rely on gridded climate data and snow remote sensing products, would be greatly improved if uncertainties in estimates of snow depth distribution in high-elevation complex terrain could be reduced. This requires an increase in the spatial and temporal coverage of observational snow data in high-elevation data-poor regions. To this end, we launched Community Snow Observations (CSO). Participating citizen scientists use Mountain Hub, a multi-platform mobile and web-based crowdsourcing application that allows users to record, submit, and instantly share geo-located snow depth, snow water equivalence (SWE) measurements, measurement location photos, and snow grain information with project scientists and other citizen scientists. The snow observations are used to validate remote sensing products and modeled snow depth distribution. The project's prototype phase focused on Thompson Pass in south-central Alaska, an important infrastructure corridor that includes avalanche terrain and the Lowe River drainage and is essential to the City of Valdez and the fisheries of Prince William Sound. This year's efforts included website development, expansion of the Mountain Hub tool, and recruitment of citizen scientists through a combination of social media outreach, community presentations, and targeted recruitment of local avalanche professionals. We also conducted two intensive field data collection campaigns that coincided with an aerial photogrammetric survey. With more than 400 snow depth observations, we have generated a new snow remote-sensing product that better matches actual SWE quantities for Thompson Pass. In the next phase of the citizen science portion of this project we will focus on expanding our group of participants to a larger geographic area in Alaska, further develop our partnership with Mountain Hub, and build relationships in new communities as we conduct a photogrammetric survey in a different region next year.

Influence of spatial resolution on precipitation simulations for the central Andes Mountains

NASA Astrophysics Data System (ADS)

Trachte, Katja; Bendix, Jörg

2013-04-01

The climate of South America is highly influenced by the north-south oriented Andes Mountains. Their complex structure causes modifications of large-scale atmospheric circulations resulting in various mesoscale phenomena as well as a high variability in the local conditions. Due to their height and length the terrain generates distinctly climate conditions between the western and the eastern slopes. While in the tropical regions along the western flanks the conditions are cold and arid, the eastern slopes are dominated by warm-moist and rainy air coming from the Amazon basin. Below 35° S the situation reverses with rather semiarid conditions in the eastern part and temperate rainy climate along southern Chile. Generally, global circulation models (GCMs) describe the state of the global climate and its changes, but are disabled to capture regional or even local features due to their coarse resolution. This is particularly true in heterogeneous regions such as the Andes Mountains, where local driving features, e. g. local circulation systems, highly varies on small scales and thus, lead to a high variability of rainfall distributions. An appropriate technique to overcome this problem and to gain regional and local scale rainfall information is the dynamical downscaling of the global data using a regional climate model (RCM). The poster presents results of the evaluation of the performance of the Weather Research and Forecasting (WRF) model over South America with special focus on the central Andes Mountains of Ecuador. A sensitivity study regarding the cumulus parametrization, microphysics, boundary layer processes and the radiation budget is conducted. With 17 simulations consisting of 16 parametrization scheme combinations and 1 default run a suitable model set-up for climate research in this region is supposed to be evaluated. The simulations were conducted in a two-way nested mode i) to examine the best physics scheme combination for the target and ii) to analyze the impact of spatial resolution and thus, the representation of the terrain on the result.

Experimental Modeling of the Effect of Terrain Slope on Marginal Burning

Treesearch

X. Zhou; S. Mahalingam; D. Weise

2005-01-01

A series of laboratory fire spread experiments were completed to analyze the effect of terrain slope on marginal burning behavior of live chaparral shrub fuels that grow in the mountains of southern California. We attempted to burn single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient conditions. Seventy-three (or 42...

Comparison of the sensitivity of landscape-fire-succession models to variation in terrain, fuel pattern, climate and weather.

Treesearch

Geoffrey J. Cary; Robert E. Keane; Robert H. Gardner; Sandra Lavorel; Mike D. Flannigan; Ian D. Davies; Chao Li; James M. Lenihan; T. Scott Rupp; Florent Mouillot

2006-01-01

The purpose of this study was to compare the sensitivity of nlodelled area burned to environmental factors across a range of independently-developed landscape-fire-succession models. The sensitivity of area burned to variation in four factors, namely terrain (flat, undulating and mountainous), fuel pattern (finely and coarsely clumped), climate (observed, warmer &...

Comparison of the sensitivity of landscape-fire-succession models to variation in terrain, fuel pattern, climate and weather

Treesearch

Geoffrey J. Cary; Robert E. Keane; Robert H. Gardner; Sandra Lavorel; Michael D. Flannigan; Ian D. Davies; Chao Li; James M. Lenihan; T. Scott Rupp; Florent Mouillot

2006-01-01

The purpose of this study was to compare the sensitivity of modelled area burned to environmental factors across a range of independently-developed landscape-fire-succession models. The sensitivity of area burned to variation in four factors, namely terrain (flat, undulating and mountainous), fuel pattern (finely and coarsely clumped), climate (observed, warmer &...

Detection of ground fog in mountainous areas from MODIS (Collection 051) daytime data using a statistical approach

NASA Astrophysics Data System (ADS)

Schulz, Hans Martin; Thies, Boris; Chang, Shih-Chieh; Bendix, Jörg

2016-03-01

The mountain cloud forest of Taiwan can be delimited from other forest types using a map of the ground fog frequency. In order to create such a frequency map from remotely sensed data, an algorithm able to detect ground fog is necessary. Common techniques for ground fog detection based on weather satellite data cannot be applied to fog occurrences in Taiwan as they rely on several assumptions regarding cloud properties. Therefore a new statistical method for the detection of ground fog in mountainous terrain from MODIS Collection 051 data is presented. Due to the sharpening of input data using MODIS bands 1 and 2, the method provides fog masks in a resolution of 250 m per pixel. The new technique is based on negative correlations between optical thickness and terrain height that can be observed if a cloud that is relatively plane-parallel is truncated by the terrain. A validation of the new technique using camera data has shown that the quality of fog detection is comparable to that of another modern fog detection scheme developed and validated for the temperate zones. The method is particularly applicable to optically thinner water clouds. Beyond a cloud optical thickness of ≈ 40, classification errors significantly increase.

Accuracy assessment of linear spectral mixture model due to terrain undulation

NASA Astrophysics Data System (ADS)

Wang, Tianxing; Chen, Songlin; Ma, Ya

2008-12-01

Mixture spectra are common in remote sensing due to the limitations of spatial resolution and the heterogeneity of land surface. During the past 30 years, a lot of subpixel model have developed to investigate the information within mixture pixels. Linear spectral mixture model (LSMM) is a simper and more general subpixel model. LSMM also known as spectral mixture analysis is a widely used procedure to determine the proportion of endmembers (constituent materials) within a pixel based on the endmembers' spectral characteristics. The unmixing accuracy of LSMM is restricted by variety of factors, but now the research about LSMM is mostly focused on appraisement of nonlinear effect relating to itself and techniques used to select endmembers, unfortunately, the environment conditions of study area which could sway the unmixing-accuracy, such as atmospheric scatting and terrain undulation, are not studied. This paper probes emphatically into the accuracy uncertainty of LSMM resulting from the terrain undulation. ASTER dataset was chosen and the C terrain correction algorithm was applied to it. Based on this, fractional abundances for different cover types were extracted from both pre- and post-C terrain illumination corrected ASTER using LSMM. Simultaneously, the regression analyses and the IKONOS image were introduced to assess the unmixing accuracy. Results showed that terrain undulation could dramatically constrain the application of LSMM in mountain area. Specifically, for vegetation abundances, a improved unmixing accuracy of 17.6% (regression against to NDVI) and 18.6% (regression against to MVI) for R2 was achieved respectively by removing terrain undulation. Anyway, this study indicated in a quantitative way that effective removal or minimization of terrain illumination effects was essential for applying LSMM. This paper could also provide a new instance for LSMM applications in mountainous areas. In addition, the methods employed in this study could be effectively used to evaluate different algorithms of terrain undulation correction for further study.

Assessing the competing roles of model resolution and meteorological forcing fidelity in hyperresolution simulations of snowpack and streamflow in the southern Rocky Mountains

NASA Astrophysics Data System (ADS)

Gochis, D. J.; Dugger, A. L.; Karsten, L. R.; Barlage, M. J.; Sampson, K. M.; Yu, W.; Pan, L.; McCreight, J. L.; Howard, K.; Busto, J.; Deems, J. S.

2017-12-01

Hydrometeorological processes vary over comparatively short length scales in regions of complex terrain such as the southern Rocky Mountains. Changes in temperature, precipitation, wind and solar radiation can vary significantly across elevation gradients, terrain landform and land cover conditions throughout the region. Capturing such variability in hydrologic models can necessitate the utilization of so-called `hyper-resolution' spatial meshes with effective element spacings of less than 100m. However, it is often difficult to obtain meteorological forcings of high quality in such regions at those resolutions which can result in significant uncertainty in fundamental in hydrologic model inputs. In this study we examine the comparative influences of meteorological forcing data fidelity and spatial resolution on seasonal simulations of snowpack evolution, runoff and streamflow in a set of high mountain watersheds in southern Colorado. We utilize the operational, NOAA National Water Model configuration of the community WRF-Hydro system as a baseline and compare against it, additional model scenarios with differing specifications of meteorological forcing data, with and without topographic downscaling adjustments applied, with and without experimental high resolution radar derived precipitation estimates and with WRF-Hydro configurations of progressively finer spatial resolution. The results suggest significant influence from and importance of meteorological downscaling techniques in controlling spatial distributions of meltout and runoff timing. The use of radar derived precipitation exhibits clear sensitivity on hydrologic simulation skill compared with the use of coarser resolution, background precipitation analyses. Advantages and disadvantages of the utilization of progressively higher resolution model configurations both in terms of computational requirements and model fidelity are also discussed.

Temperature-profile methods for estimating percolation rates in arid environments

USGS Publications Warehouse

Constantz, Jim; Tyler, Scott W.; Kwicklis, Edward

2003-01-01

Percolation rates are estimated using vertical temperature profiles from sequentially deeper vadose environments, progressing from sediments beneath stream channels, to expansive basin-fill materials, and finally to deep fractured bedrock underlying mountainous terrain. Beneath stream channels, vertical temperature profiles vary over time in response to downward heat transport, which is generally controlled by conductive heat transport during dry periods, or by advective transport during channel infiltration. During periods of stream-channel infiltration, two relatively simple approaches are possible: a heat-pulse technique, or a heat and liquid-water transport simulation code. Focused percolation rates beneath stream channels are examined for perennial, seasonal, and ephemeral channels in central New Mexico, with estimated percolation rates ranging from 100 to 2100 mm d−1 Deep within basin-fill and underlying mountainous terrain, vertical temperature gradients are dominated by the local geothermal gradient, which creates a profile with decreasing temperatures toward the surface. If simplifying assumptions are employed regarding stratigraphy and vapor fluxes, an analytical solution to the heat transport problem can be used to generate temperature profiles at specified percolation rates for comparison to the observed geothermal gradient. Comparisons to an observed temperature profile in the basin-fill sediments beneath Frenchman Flat, Nevada, yielded water fluxes near zero, with absolute values <10 mm yr−1 For the deep vadose environment beneath Yucca Mountain, Nevada, the complexities of stratigraphy and vapor movement are incorporated into a more elaborate heat and water transport model to compare simulated and observed temperature profiles for a pair of deep boreholes. Best matches resulted in a percolation rate near zero for one borehole and 11 mm yr−1 for the second borehole.

Detectability of change in winter precipitation within mountain landscapes: Spatial patterns and uncertainty

NASA Astrophysics Data System (ADS)

Silverman, N. L.; Maneta, M. P.

2016-06-01

Detecting long-term change in seasonal precipitation using ground observations is dependent on the representativity of the point measurement to the surrounding landscape. In mountainous regions, representativity can be poor and lead to large uncertainties in precipitation estimates at high elevations or in areas where observations are sparse. If the uncertainty in the estimate is large compared to the long-term shifts in precipitation, then the change will likely go undetected. In this analysis, we examine the minimum detectable change across mountainous terrain in western Montana, USA. We ask the question: What is the minimum amount of change that is necessary to be detected using our best estimates of precipitation in complex terrain? We evaluate the spatial uncertainty in the precipitation estimates by conditioning historic regional climate model simulations to ground observations using Bayesian inference. By using this uncertainty as a null hypothesis, we test for detectability across the study region. To provide context for the detectability calculations, we look at a range of future scenarios from the Coupled Model Intercomparison Project 5 (CMIP5) multimodel ensemble downscaled to 4 km resolution using the MACAv2-METDATA data set. When using the ensemble averages we find that approximately 65% of the significant increases in winter precipitation go undetected at midelevations. At high elevation, approximately 75% of significant increases in winter precipitation are undetectable. Areas where change can be detected are largely controlled by topographic features. Elevation and aspect are key characteristics that determine whether or not changes in winter precipitation can be detected. Furthermore, we find that undetected increases in winter precipitation at high elevation will likely remain as snow under climate change scenarios. Therefore, there is potential for these areas to offset snowpack loss at lower elevations and confound the effects of climate change on water resources.

Characterizing the physical-basis of orographic rainfall retrieval errors due to terrain artifacts on GPM-DPR reflectivity profiles

NASA Astrophysics Data System (ADS)

Arulraj, M.; Barros, A. P.

2017-12-01

GPM-DPR reflectivity profiles in mountainous regions are severely handicapped by low level ground-clutter artifacts which have different error characteristics depending on landform (upwind slopes of high mountains versus complex topography in middle-mountains) and precipitation regime. These artifacts result in high detection and estimation errors especially in mid-latitude and tropical mountain regions where low-level light precipitation and complex multi-layer clouds interact with incoming storms. Here, we present results assessment studies in the Southern Appalachian Mountains (SAM) and preliminary results over the eastern slopes of the Andes using ground-based observations from the long-term hydrometeorological networks and model studies toward developing a physically-based framework to systematically identify and attribute measurement errors. Specifically, the focus is on events when GPM-DPR Ka- and Ku- Band precipitation radar misses low-level precipitation with vertical altitude less than 2 km AGL (above ground level). For this purpose, ground-based MRR and Parsivel disdrometer observations near the surface are compared with the reflectivity profiles observed by the GPM-DPR overpasses, the raindrop-size spectra are used to classify the precipitation regime associated with different classes of detection and estimation errors. This information will be used along with a coupled rainfall dynamics and radar simulator model to 1) merge the low-level GPM-DPR measured reflectivity with the MRR reflectivities optimally under strict physically-based constraints and 2) build a library of reflectivity profile corrections. Finally, preliminary 4D analysis of the organization of reflectivity correction modes, microphysical regimes, topography and storm environment will be presented toward developing a general physically-based error model.

An assessment of differences in gridded precipitation datasets in complex terrain

NASA Astrophysics Data System (ADS)

Henn, Brian; Newman, Andrew J.; Livneh, Ben; Daly, Christopher; Lundquist, Jessica D.

2018-01-01

Hydrologic modeling and other geophysical applications are sensitive to precipitation forcing data quality, and there are known challenges in spatially distributing gauge-based precipitation over complex terrain. We conduct a comparison of six high-resolution, daily and monthly gridded precipitation datasets over the Western United States. We compare the long-term average spatial patterns, and interannual variability of water-year total precipitation, as well as multi-year trends in precipitation across the datasets. We find that the greatest absolute differences among datasets occur in high-elevation areas and in the maritime mountain ranges of the Western United States, while the greatest percent differences among datasets relative to annual total precipitation occur in arid and rain-shadowed areas. Differences between datasets in some high-elevation areas exceed 200 mm yr-1 on average, and relative differences range from 5 to 60% across the Western United States. In areas of high topographic relief, true uncertainties and biases are likely higher than the differences among the datasets; we present evidence of this based on streamflow observations. Precipitation trends in the datasets differ in magnitude and sign at smaller scales, and are sensitive to how temporal inhomogeneities in the underlying precipitation gauge data are handled.

Unsteady density-current equations for highly curved terrain

NASA Technical Reports Server (NTRS)

Sivakumaran, N. S.; Dressler, R. F.

1989-01-01

New nonlinear partial differential equations containing terrain curvature and its rate of change are derived that describe the flow of an atmospheric density current. Unlike the classical hydraulic-type equations for density currents, the new equations are valid for two-dimensional, gradually varied flow over highly curved terrain, hence suitable for computing unsteady (or steady) flows over arbitrary mountain/valley profiles. The model assumes the atmosphere above the density current exerts a known arbitrary variable pressure upon the unknown interface. Later this is specialized to the varying hydrostatic pressure of the atmosphere above. The new equations yield the variable velocity distribution, the interface position, and the pressure distribution that contains a centrifugal component, often significantly larger than its hydrostatic component. These partial differential equations are hyperbolic, and the characteristic equations and characteristic directions are derived. Using these to form a characteristic mesh, a hypothetical unsteady curved-flow problem is calculated, not based upon observed data, merely as an example to illustrate the simplicity of their application to unsteady flows over mountains.

Intensity of geomorphological processes in NW sector of Pacific rim marginal mountain belts

NASA Astrophysics Data System (ADS)

Lebedeva, Ekaterina; Shvarev, Sergey; Gotvansky, Veniamin

2014-05-01

Continental marginal mountains, including the mountain belts of Russian Far East, are characterized by supreme terrain contrast, mosaic structure of surface and crust, and rich complex of modern endogenous processes - volcanism, seismicity, and vertical movements. Unstable state of geomorphological systems and activity of relief forming processes here is caused also by deep dissected topography and the type and amount of precipitation. Human activities further stimulate natural processes and increase the risk of local disasters. So these territories have high intensity (or tension) of geomorphological processes. Intensity in the authors' understanding is willingness of geomorphological system to be out of balance, risk of disaster under external and internal agent, both natural and human. Mapping with quantitative accounting of intensity of natural and human potential impact is necessary for indication the areal distribution trends of geomorphological processes intensity and zones of potential risk of disasters. Methods of map drowning up are based on several criteria analyzing: 1) total terrain-form processes and their willingness to be a hazard-like, 2) existence, peculiarity and zoning of external agents which could cause extreme character of base processes within the territory, 3) peculiarity of terrain morphology which could cause hazard way of terrain-form processes. Seismic activity is one of the most important factors causing activation of geomorphological processes and contributing to the risk of dangerous situations. Earthquake even small force can provoke many catastrophic processes: landslides, mudslides, avalanches and mudflows, tsunami and others. Seismic gravitational phenomenons of different scale accompany almost all earthquakes of intensity 7-8 points and above, and some processes, such as avalanches, activated by seismic shocks intensity about 1-3 points. In this regard, we consider it important selection of high intensity seismic zones in marginal-continental mountain systems and also offer to give them extra points of tension, the number of which increases depending on the strength of the shock. Such approach allows to identify clearly the most potentially hazardous areas where there may be various, sometimes unpredictable scale catastrophic processes, provoked intense underground tremors. We also consider the impact of the depth of topography dissection and the total amount of precipitation. The marginal-continental mountain systems have often radically different moistening of coastal and inland slopes. And this difference can be 500, 1000 mm and more, that, undoubtedly, affects the course and intensity of geomorphological processes on slopes of different exposures. The total evaluation of intensity of geomorphologic processes exceeding 15 points is considered to be potentially catastrophic. At 10-15 points tension geomorphologic processes is extremely high, and at 5-10 points - high, less than 5 points - low. The maps of the key areas of the Russian Far East - Kamchatka and the north of Kuril Islands, Sakhalin and the Western Okhotsk region were compiled. These areas have differences in geodynamic regimes, landscape-climatic and anthropogenic conditions and highly significant in relation to the differentiated estimation of geomorphologic tension. The growth of intensity of geomorphological processes toward the Pacific Ocean was recorded: from 7-10 points in Western Okhotsk region to 10-13 at Sakhalin and to 13-15 points for Kamchatka.

Accuracy of retrieving temperature and humidity profiles by ground-based microwave radiometry in truly complex terrain

NASA Astrophysics Data System (ADS)

Massaro, G.; Stiperski, I.; Pospichal, B.; Rotach, M. W.

2015-08-01

Within the Innsbruck Box project, a ground-based microwave radiometer (RPG-HATPRO) was operated in the Inn Valley (Austria), in very complex terrain, between September 2012 and May 2013 to obtain temperature and humidity vertical profiles of the full troposphere with a specific focus on the valley boundary layer. In order to assess its performance in a deep alpine valley, the profiles obtained by the radiometer with different retrieval algorithms based on different climatologies are compared to local radiosonde data. A retrieval that is improved with respect to the one provided by the manufacturer, based on better resolved data, shows a significantly smaller root mean square error (RMSE), both for the temperature and humidity profiles. The improvement is particularly substantial at the heights close to the mountaintop level and in the upper troposphere. Lower-level inversions, common in an alpine valley, are resolved to a satisfactory degree. On the other hand, upper-level inversions (above 1200 m) still pose a significant challenge for retrieval. For this purpose, specialized retrieval algorithms were developed by classifying the radiosonde climatologies into specialized categories according to different criteria (seasons, daytime, nighttime) and using additional regressors (e.g., measurements from mountain stations). The training and testing on the radiosonde data for these specialized categories suggests that a classification of profiles that reproduces meaningful physical characteristics can yield improved targeted specialized retrievals. A novel and very promising method of improving the profile retrieval in a mountainous region is adding further information in the retrieval, such as the surface temperature at fixed levels along a topographic slope or from nearby mountaintops.

The Alpini Effect: Why the US Army Should Train Units for Mountain Warfare

DTIC Science & Technology

2014-05-22

than on training units and its leaders how to conduct mountain warfare.34 MOUNTAINS AND WHERE THEY ARE It is essential to understand what a...The first level is considered key terrain in counterinsurgencies, such as what the US Army has experienced in Afghanistan, because this is where...copyrighted. 40Andrew Young, “Distance to the Horizon,” San Diego State Department of Astronomy , http://mintaka.sdsu.edu/GF/explain/atmos_refr

Mountain permafrost, glacier thinning, and slope stability - a perspective from British Columbia (and Alaska)

NASA Astrophysics Data System (ADS)

Geertsema, Marten

2016-04-01

The association of landslides with thinning glaciers and mapped, or measured, mountain permafrost is increasing. Glacier thinning debuttresses slopes and promotes joint expansion. It is relatively easy to map. Permafrost, a thermal condition, is generally not visually detectible, and is difficult to map. Much mountain permafrost may have been overlooked in hazard analysis. Identifying, and characterizing mountain permafrost, and its influence on slope instability is crucial for hazard and risk analysis in mountainous terrain. Rock falls in mountains can be the initial event in process chains. They can transform into rock avalanches, debris flows or dam burst floods, travelling many kilometres, placing infrastructure and settlements at risk.

Predicting landslides related to clearcut logging, northwestern California, U.S.A.

Treesearch

David J. Furbish; Raymond M. Rice

1983-01-01

Abstract - Landslides related to clearcut logging are a significant source of erosion in the mountains of northwestern California. Forest managers, therefore, frequently must include assessments of landslide risk in their land-use plans. A quantitative method is needed to predict such risk over large areas of rugged mountainous terrain. From air photographs, data...

Using Digital Terrain Modeling to Predict Ecological Types in the Balsam Mountains of Western North Carolina

Treesearch

Richard H. Odom; W. Henry McNab

2000-01-01

Relationships between overstory composition and topographic conditions were studied in high-elevation (>1300 meters) forests in the Balsam Mountains of western North Carolina to determine whether models could be developed to predict the occurrence of number vegetative communities in relation to topographic variables (elevation, landscape position, surface geometry,...

High Resolution Wind Direction and Speed Information for Support of Fire Operations

Treesearch

B.W. Butler; J.M. Forthofer; M.A. Finney; L.S. Bradshaw; R. Stratton

2006-01-01

Computational Fluid Dynamics (CFD) technology has been used to model wind speed and direction in mountainous terrain at a relatively high resolution compared to other readily available technologies. The process termed “gridded wind” is not a forecast, but rather represents a method for calculating the influence of terrain on general wind flows. Gridded wind simulations...

Terrain forcing and thermal winds in a mountain pass

NASA Astrophysics Data System (ADS)

Clifton, A.; Daniels, M. H.; Lehning, M.

2010-12-01

As the European wind market matures, energy prospectors are increasingly looking to more challenging terrain and conditions, for example those found in the mountains and passes of the Alps. These locations present very different technical challenges to those found in the flatter plains of Northern Europe, the US midwest or offshore. There is little public data available on wind regimes in these areas, and what information there is is not often examined in conjunction with other data for the same area. Consequently it is difficult to estimate the effect of terrain or surface cover on the wind resource. We present selected data collected in a mountain pass during the winter of 2009 / 2010. Data were collected on site at 36, 54 and 77m above ground using sonic anemometers, and at the surface using small portable weather stations. Preliminary analysis of data from the sonic anemometers shows that flow in the pass is often low shear compared to an unconstrained boundary layer, although the log law using mean velocities does fit around half of the data that was collected. However, the applicability of the log law is questionable as calculated roughness lengths are of a similar order of magnitude to the measurement height. Further analysis of the sonic anemometer data does not suggest an equilibrium flux layer. Flow is generally along the major axis of the pass, indicating that the terrain acted to channel flow, compared to synoptic conditions. Larger-scale data from numerical weather prediction models is also available. These data are analysed in conjunction with simulations using the regional weather prediction model, ARPS, to show both the impact of terrain and surface heat fluxes on the wind profiles at different points in the pass. We use our data and results to show the potential effects on flow characteristics at typical wind turbine disk heights in the pass. We also suggest how future wind resource measurement and modeling campaigns in similar locations might be modified to help identify thermal and terrain effects on the wind resources.

Surface layer characteristics derived from fast-response micrometeorological observations over a mountain peak in the central Himalayas

NASA Astrophysics Data System (ADS)

Solanki, Raman; Dhaka, Surendra; Rajeev, Kunjukrishnapillai; Singh, Narendra; Nadimpally, Kirankumar

Diurnal evolution of atmospheric boundary layer over hilly terrains is highly complex and least understood. Fast-response micrometeorological observations carried out at Manora Peak, Nainital (29.2°N, 79.3°E, 1960 m ASL), a hill station located in the Central Himalayas during March-2013 to February-2014 has been used to investigate diurnal variations in the surface layer characteristics, energy budget and atmospheric circulation over complex terrains. This study mainly employs tower-based sonic anemometer observations (25 Hz) carried out at two levels (12 m and 27 m above the ground level) which are used to derive the variations of zonal, meridional and vertical winds, virtual temperature, momentum flux, turbulent kinetic energy, and Monin-Obukhov stability parameter during fair-weather conditions. In general, this station is manifested by warm and dry conditions as well as relatively high wind speed during pre-monsoon season (March-May); while highly moist conditions prevail during the summer monsoon season (June-September). The sensible heat flux (SHF) undergoes a prominent diurnal variation during winter and pre-monsoon seasons with peak values (200 to 400 Wm-2) occurring between 11-15 Local Time (LT) and weakly negative values (typically -20 Wm-2) during night, the latter indicating a downward transfer of heat from atmosphere to surface. The noon-time peak values systematically increases from winter to pre-monsoon season. Remarkably, the large noon-time values of SHF observed during the pre-monsoon season over this station (peak SHF of more than 400 Wm-2 during May) arise from the forced lifting of air masses, caused by the prevailing horizontal winds that blow perpendicular to the mountain. The intricate details of the surface layer parameters and fluxes over this site will assist in investigating how such a complex topography influences the flux generation process.

Comparisons of Rain Estimates from Ground Radar and Satellite Over Mountainous Regions

NASA Technical Reports Server (NTRS)

Lin, Xin; Kidd, Chris; Tao, Jing; Barros, Ana

2016-01-01

A high-resolution rainfall product merging surface radar and an enhanced gauge network is used as a reference to examine two operational surface radar rainfall products over mountain areas. The two operational rainfall products include radar-only and conventional-gauge-corrected radar rainfall products. Statistics of rain occurrence and rain amount including their geographical, seasonal, and diurnal variations are examined using 3-year data. It is found that the three surface radar rainfall products in general agree well with one another over mountainous regions in terms of horizontal mean distributions of rain occurrence and rain amount. Frequency of rain occurrence and fraction of rain amount also indicate similar distribution patterns as a function of rain intensity. The diurnal signals of precipitation over mountain ridges are well captured and joint distributions of coincident raining samples indicate reasonable correlations during both summer and winter. Factors including undetected low-level precipitation, limited availability of gauges for correcting the Z-R relationship over the mountains, and radar beam blocking by mountains are clearly noticed in the two conventional radar rainfall products. Both radar-only and conventional-gauge-corrected radar rainfall products underestimate the rain occurrence and fraction of rain amount at intermediate and heavy rain intensities. Comparison of PR and TMI against a surface radar-only rainfall product indicates that the PR performs equally well with the high-resolution radar-only rainfall product over complex terrains at intermediate and heavy rain intensities during the summer and winter. TMI, on the other hand, requires improvement to retrieve wintertime precipitation over mountain areas.

Wind Resource Assessment in Complex Terrain with a High-Resolution Numerical Weather Prediction Model

NASA Astrophysics Data System (ADS)

Gruber, Karin; Serafin, Stefano; Grubišić, Vanda; Dorninger, Manfred; Zauner, Rudolf; Fink, Martin

2014-05-01

A crucial step in planning new wind farms is the estimation of the amount of wind energy that can be harvested in possible target sites. Wind resource assessment traditionally entails deployment of masts equipped for wind speed measurements at several heights for a reasonably long period of time. Simplified linear models of atmospheric flow are then used for a spatial extrapolation of point measurements to a wide area. While linear models have been successfully applied in the wind resource assessment in plains and offshore, their reliability in complex terrain is generally poor. This represents a major limitation to wind resource assessment in Austria, where high-altitude locations are being considered for new plant sites, given the higher frequency of sustained winds at such sites. The limitations of linear models stem from two key assumptions in their formulation, the neutral stratification and attached boundary-layer flow, both of which often break down in complex terrain. Consequently, an accurate modeling of near-surface flow over mountains requires the adoption of a NWP model with high horizontal and vertical resolution. This study explores the wind potential of a site in Styria in the North-Eastern Alps. The WRF model is used for simulations with a maximum horizontal resolution of 800 m. Three nested computational domains are defined, with the innermost one encompassing a stretch of the relatively broad Enns Valley, flanked by the main crest of the Alps in the south and the Nördliche Kalkalpen of similar height in the north. In addition to the simulation results, we use data from fourteen 10-m wind measurement sites (of which 7 are located within valleys and 5 near mountain tops) and from 2 masts with anemometers at several heights (at hillside locations) in an area of 1600 km2 around the target site. The potential for wind energy production is assessed using the mean wind speed and turbulence intensity at hub height. The capacity factor is also evaluated, considering the frequency of wind speed between cut-in and cut-out speed and of winds with a low vertical velocity component only. Wind turbines do not turn on at wind speeds below cut-in speed. Wind turbines are taken off from the generator in the case of wind speeds higher than cut-out speed and inclination angles of the wind vector greater than 8o. All of these parameters were computed at each model grid point in the innermost domain in order to map their spatial variability. The results show that in complex terrain the annual mean wind speed at hub height is not sufficient to predict the capacity factor of a turbine; vertical wind speed and the frequency of horizontal wind speed out of the range of cut-in and cut-out speed contribute substantially to a reduction of the energy harvest and locally high turbulence may considerably raise the building costs.

Geophysical techniques for reconnaissance investigations of soils and surficial deposits in mountainous terrain

USGS Publications Warehouse

Olson, C.G.; Doolittle, J.A.

1985-01-01

Two techniques were assessed for their capabilities in reconnaissance studies of soil characteristics: depth to the water table and depth to bedrock beneath surficial deposits in mountainous terrain. Ground-penetrating radar had the best near-surface resolution in the upper 2 m of the profile and provided continuous interpretable imagery of soil profiles and bedrock surfaces. Where thick colluvium blankets side slopes, the GPR could not consistently define the bedrock interface. In areas with clayey or shaley sediments, the GPR is also more limited in defining depth and is less reliable. Seismic refraction proved useful in determining the elevation of the water table and depth to bedrock, regardless of thickness of overlying material, but could not distinguish soil-profile characteristics.-from Authors

Limitations of one-dimensional mesoscale PBL parameterizations in reproducing mountain-wave flows

DOE PAGES

Munoz-Esparza, Domingo; Sauer, Jeremy A.; Linn, Rodman R.; ...

2015-12-08

In this study, mesoscale models are considered to be the state of the art in modeling mountain-wave flows. Herein, we investigate the role and accuracy of planetary boundary layer (PBL) parameterizations in handling the interaction between large-scale mountain waves and the atmospheric boundary layer. To that end, we use recent large-eddy simulation (LES) results of mountain waves over a symmetric two-dimensional bell-shaped hill [Sauer et al., J. Atmos. Sci. (2015)], and compare them to four commonly used PBL schemes. We find that one-dimensional PBL parameterizations produce reasonable agreement with the LES results in terms of vertical wavelength, amplitude of velocitymore » and turbulent kinetic energy distribution in the downhill shooting flow region. However, the assumption of horizontal homogeneity in PBL parameterizations does not hold in the context of these complex flow configurations. This inappropriate modeling assumption results in a vertical wavelength shift producing errors of ≈ 10 m s–1 at downstream locations due to the presence of a coherent trapped lee wave that does not mix with the atmospheric boundary layer. In contrast, horizontally-integrated momentum flux derived from these PBL schemes displays a realistic pattern. Therefore results from mesoscale models using ensembles of one-dimensional PBL schemes can still potentially be used to parameterize drag effects in general circulation models. Nonetheless, three-dimensional PBL schemes must be developed in order for mesoscale models to accurately represent complex-terrain and other types of flows where one-dimensional PBL assumptions are violated.« less

Comparison and Analysis of Geometric Correction Models of Spaceborne SAR

PubMed Central

Jiang, Weihao; Yu, Anxi; Dong, Zhen; Wang, Qingsong

2016-01-01

Following the development of synthetic aperture radar (SAR), SAR images have become increasingly common. Many researchers have conducted large studies on geolocation models, but little work has been conducted on the available models for the geometric correction of SAR images of different terrain. To address the terrain issue, four different models were compared and are described in this paper: a rigorous range-doppler (RD) model, a rational polynomial coefficients (RPC) model, a revised polynomial (PM) model and an elevation derivation (EDM) model. The results of comparisons of the geolocation capabilities of the models show that a proper model for a SAR image of a specific terrain can be determined. A solution table was obtained to recommend a suitable model for users. Three TerraSAR-X images, two ALOS-PALSAR images and one Envisat-ASAR image were used for the experiment, including flat terrain and mountain terrain SAR images as well as two large area images. Geolocation accuracies of the models for different terrain SAR images were computed and analyzed. The comparisons of the models show that the RD model was accurate but was the least efficient; therefore, it is not the ideal model for real-time implementations. The RPC model is sufficiently accurate and efficient for the geometric correction of SAR images of flat terrain, whose precision is below 0.001 pixels. The EDM model is suitable for the geolocation of SAR images of mountainous terrain, and its precision can reach 0.007 pixels. Although the PM model does not produce results as precise as the other models, its efficiency is excellent and its potential should not be underestimated. With respect to the geometric correction of SAR images over large areas, the EDM model has higher accuracy under one pixel, whereas the RPC model consumes one third of the time of the EDM model. PMID:27347973

Controls on valley width in mountainous landscapes: the role of landsliding and implications for salmonid habitat

Treesearch

C. May; J. Roering; L.S. Eaton; K.M. Burnett

2013-01-01

A fundamental yet unresolved question in fluvial geomorphology is what controls the width of valleys in mountainous terrain. Establishing a predictive relation for valley floor width is critical for realizing links between aquatic ecology and geomorphology because the most productive riverine habitats often occur in low-gradient streams with broad floodplains. Working...

Predicting behavior and size of crown fires in the northern Rocky Mountains

Treesearch

Richard C. Rothermel

1991-01-01

Describes methods for approximating behavior and size of a wind-driven crown fire in mountainous terrain. Covers estimation of average rate of spread, energy release from tree crowns and surface fuel, fireline intensity, flame length, and unit area power of the fire and ambient wind. Plume-dominated fires, which may produce unexpectedly fast spread rates even with low...

Timber supply and demand assessment of the Green and White Mountain National Forests' market area

Treesearch

Chris B. LeDoux; Paul E. Sendak; William H. McWilliams; Neil Huyler; Thomas Malecek; Worthen Muzzey; Toni Jones

2001-01-01

This report describes a timber supply and demand assessment of the Green and White Mountain National Forests' market area using USDA Forest Service, Forest Inventory and Analysis data, production information provided by forest industry, and a stump-to-mill logging cost-prediction model. Nonavailable timberland that includes reserve and steep-terrain lands is...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Xuhui

This is the AmeriFlux version of the carbon flux data for the site US-GMF Great Mountain Forest. Site Description - The experimental site is in the Great Mountain Forest on moderately hilly terrain in Norfolk, Connecticut. The site is a naturally regenerating forest impacted by fires, logging, hurricanes, and cultivation over the past century. The site switched from a continuous measurement mode to a campaign mode on DOY 125, 2004.

Infantry Small-Unit Mountain Operations

DTIC Science & Technology

2011-02-01

expended to traverse it.  Unique sustainment solutions. Sustainment in a mountain environment is a challenging and time-consuming process . Terrain...a particular environment during the intelligence preparation of the battlefield (IPB) process and provide the analysis to the company. The IPB...consists of a four-step process that includes—  Defining the operational environment.  Describing environmental effects on operations.  Evaluating the

Charon Complexity

NASA Image and Video Library

2015-09-10

This image of Pluto's largest moon Charon, taken by NASA's New Horizons spacecraft 10 hours before its closest approach to Pluto on July 14, 2015 from a distance of 290,000 miles (470,000 kilometers), is a recently downlinked, much higher quality version of a Charon image released on July 15. Charon, which is 750 miles (1,200 kilometers) in diameter, displays a surprisingly complex geological history, including tectonic fracturing; relatively smooth, fractured plains in the lower right; several enigmatic mountains surrounded by sunken terrain features on the right side; and heavily cratered regions in the center and upper left portion of the disk. There are also complex reflectivity patterns on Charon's surface, including bright and dark crater rays, and the conspicuous dark north polar region at the top of the image. The smallest visible features are 2.9 miles 4.6 kilometers) in size. http://photojournal.jpl.nasa.gov/catalog/PIA19932

Assessment of integrated electrical resistivity data on complex aquifer structures in NE Nuba Mountains - Sudan

NASA Astrophysics Data System (ADS)

Mohamed, N. E.; Yaramanci, U.; Kheiralla, K. M.; Abdelgalil, M. Y.

2011-07-01

Two geophysical techniques were integrated to map the groundwater aquifers on complex geological settings, in the crystalline basement terrain in northeast Nuba Mountains. The water flow is structurally controlled by the northwest-southeast extensional faults as one of several in-situ deformational patterns that are attributed to the collision of the Pan-African oceanic assemblage of the Nubian shield against the pre-Pan African continental crust to the west. The structural lineaments and drainage systems have been enhanced by the remote sensing technique. The geophysical techniques used are: vertical electrical soundings (VES) and electrical resistivity tomography (ERT), in addition to hydraulic conductivity measurements. These measurements were designed to overlap in order to improve the producibility of the geophysical data and to provide a better interpretation of the hydrogeological setting of the aquifer complex structure. Smooth and Block inversion schemes were attempted for the observed ERT data to study their reliability in mapping the different geometries in the complex subsurface. The VES data was conducted where ERT survey was not accessible, and inverted smoothly and merged with the ERT in the 3D resistivity grid. The hydraulic conductivity was measured for 42 water samples collected from the distributed dug wells in the study area; where extremely high saline zones were recorded and have been compared to the resistivity values in the 3D model.

Flying Fast and High: Operational Flight Planning for Maximum Data Return for Airborne Snow Observatory Mountain Surveys

NASA Astrophysics Data System (ADS)

Berisford, D. F.; Painter, T. H.; Richardson, M.; Wallach, A.; Deems, J. S.; Bormann, K. J.

2017-12-01

The Airborne Snow Observatory (ASO - http://aso.jpl.nasa.gov) uses an airborne laser scanner to map snow depth, and imaging spectroscopy to map snow albedo in order to estimate snow water equivalent and melt rate over mountainous, hydrologic basin-scale areas. Optimization of planned flight lines requires the balancing of many competing factors, including flying altitude and speed, bank angle limitation, laser pulse rate and power level, flightline orientation relative to terrain, surface optical properties, and data output requirements. These variables generally distill down to cost vs. higher resolution data. The large terrain elevation variation encountered in mountainous terrain introduces the challenge of narrow swath widths over the ridgetops, which drive tight flightline spacing and possible dropouts over the valleys due to maximum laser range. Many of the basins flown by ASO exceed 3,000m of elevation relief, exacerbating this problem. Additionally, sun angle may drive flightline orientations for higher-quality spectrometer data, which may change depending on time of day. Here we present data from several ASO missions, both operational and experimental, showing the lidar performance and accuracy limitations for a variety of operating parameters. We also discuss flightline planning strategies to maximize data density return per dollar, and a brief analysis on the effect of short turn times/steep bank angles on GPS position accuracy.

High prevalence of cattle fascioliasis in coastal areas of Thua Thien Hue province, Vietnam.

PubMed

Nguyen, Nga Thi; LE, Thinh Cong; Vo, Minh Duc Co; VAN Cao, Hoang; Nguyen, Ly Thi; Ho, Khanh Thi; Nguyen, Quyet Ngoc; Tran, Vui Quang; Matsumoto, Yasunobu

2017-06-16

In Vietnam, especially central Vietnam, patients with fascioliasis are increasingly being reported. Since the fascioliasis is zoonotic, survey on the cattle fascioliasis should be informative for the control of human fascioliasis. In this study, the prevalence of cattle fascioliasis as well as the density of the intermediate host snails, Lymnaea swinhoei and L. viridis, were studied in Thua Thien Hue (TTH) province during 2014-2015. A total of 572 cattle feces were examined from 27 communes in 9 districts. Fasciola eggs were detected in cattle from 24 communes with an average prevalence of 23.4% (134/ 572). The highest prevalence was detected in cattle in the coastal plain terrain (31.0%) followed by plain (25.5%), mountain (21.7%), and low hilly (16.2%) terrains. The highest proportion of heavy infection (>200 EPG) was observed in the coastal plain terrain (36.1%), followed by mountains (20.0%), low hills (13.0%), and plains (8.9%). Low number of heavy infection, as well as relatively low prevalence in low hills and plains were associated with the extensive use of anti-fluke treatments. High number of intermediate host snails in low hilly and plain terrains also indicate high risk of fascioliasis. In this study, the density of Lymnaea snails in the coastal plain terrain was found to be very high (17.3 snails/m 2 ) compared to that in previous studies. This is the first report indicating the recent expansion of cattle fascioliasis in the coastal region in Vietnam.

Glaciated valleys in Europe and western Asia

PubMed Central

Prasicek, Günther; Otto, Jan-Christoph; Montgomery, David R.; Schrott, Lothar

2015-01-01

In recent years, remote sensing, morphometric analysis, and other computational concepts and tools have invigorated the field of geomorphological mapping. Automated interpretation of digital terrain data based on impartial rules holds substantial promise for large dataset processing and objective landscape classification. However, the geomorphological realm presents tremendous complexity and challenges in the translation of qualitative descriptions into geomorphometric semantics. Here, the simple, conventional distinction of V-shaped fluvial and U-shaped glacial valleys was analyzed quantitatively using multi-scale curvature and a novel morphometric variable termed Difference of Minimum Curvature (DMC). We used this automated terrain analysis approach to produce a raster map at a scale of 1:6,000,000 showing the distribution of glaciated valleys across Europe and western Asia. The data set has a cell size of 3 arc seconds and consists of more than 40 billion grid cells. Glaciated U-shaped valleys commonly associated with erosion by warm-based glaciers are abundant in the alpine regions of mid Europe and western Asia but also occur at the margins of mountain ice sheets in Scandinavia. The high-level correspondence with field mapping and the fully transferable semantics validate this approach for automated analysis of yet unexplored terrain around the globe and qualify for potential applications on other planetary bodies like Mars. PMID:27019665

Influences of Appalachian orography on heavy rainfall and rainfall variability associated with the passage of hurricane Isabel by ensemble simulations

NASA Astrophysics Data System (ADS)

Oldaker, Guy; Liu, Liping; Lin, Yuh-Lang

2017-12-01

This study focuses on the heavy rainfall event associated with hurricane Isabel's (2003) passage over the Appalachian mountains of the eastern United States. Specifically, an ensemble consisting of two groups of simulations using the Weather Research and Forecasting model (WRF), with and without topography, is performed to investigate the orographic influences on heavy rainfall and rainfall variability. In general, the simulated ensemble mean with full terrain is able to reproduce the key observed 24-h rainfall amount and distribution, while the flat-terrain mean lacks in this respect. In fact, 30-h rainfall amounts are reduced by 75% with the removal of topography. Rainfall variability is also significantly increased with the presence of orography. Further analysis shows that the complex interaction between the hurricane and terrain along with contributions from varied microphysics, cumulus parametrization, and planetary boundary layer schemes have a pronounced effect on rainfall and rainfall variability. This study follows closely with a previous study, but for a different TC case of Isabel (2003). It is an important sensitivity test for a different TC in a very different environment. This study reveals that the rainfall variability behaves similarly, even with different settings of the environment.

[Pecularities of organisation and health care delivery to military servicemen under conditions of mid- and high mountains].

PubMed

Khalimov, Yu Sh; Vetryakov, O V; Makiev, R G; Kuzmich, V G

2016-01-01

The authors present an analysis of adverse climatic factors mid- and high mountains, which have a significant negative impact on fighting facility and capacity for work in military servicemen that may cause an acute mountain sickness and severe complications (high altitude pulmonary edema and high-altitude cerebral edema). Complicated mechanisms of organism disorder are shown. Sophisticated medical and tactical factors of mountain theatre of war, defining the nature of actions of troops, require special approaches to organisation of medical support. One of the major tasks of the medical service and the commanders is the timely prevention of health disorders troops in mountainous terrain.

ED09-0290-32

NASA Image and Video Library

2009-10-01

The F-16D Automatic Collision Avoidance Technology aircraft tests of the Automatic Ground Collision Avoidance System, or Auto-GCAS, included flights in areas of potentially hazardous terrain, including canyons and mountains.

Stratified flows in complex terrain

NASA Astrophysics Data System (ADS)

Retallack, Charles

The focus of this dissertation is the study of stratified atmospheric flows in the presence of complex terrain. Two large-scale field study campaigns were carried out, each with a focus on a specific archetypal terrain. Each field study involved the utilization of remote and in-situ atmospheric monitoring devices to collect experimental data. The first of the two field studies focused on pollution transport mechanisms near an escarpment. The analysis aimed to determine the combined effect of the escarpment and ambient density stratification on the flow and aerosol pollution transport. It was found that under specific atmospheric conditions, the escarpment prompted the channeling, down-mixing, and trapping of aerosol pollutant plumes. The objective of the second field campaign was the study of stratified flows in a mountain valley. Analysis revealed that buoyancy driven katabatic currents originating on the surrounding valley slopes created a scenario in which a down-slope gravity current transitioned into an intrusive gravity current. The intrusive gravity current propagated near the interface of a density stratified lower ambient layer and a non-stratified upper ambient layer. A combination of shallow water theory and energy arguments is used to produce a model for the propagation of a gravity current moving along the interface of a homogeneous ambient layer and a linearly stratified layer. It is found that the gravity current propagating entirely within the homogeneous layer travels at the greatest speed. As the relative density of the gravity current is increased, the gravity current begins to slump below the interface of the two layers and the propagation speed decreases.

Vertical Accuracy Evaluation of Aster GDEM2 Over a Mountainous Area Based on Uav Photogrammetry

NASA Astrophysics Data System (ADS)

Liang, Y.; Qu, Y.; Guo, D.; Cui, T.

2018-05-01

Global digital elevation models (GDEM) provide elementary information on heights of the Earth's surface and objects on the ground. GDEMs have become an important data source for a range of applications. The vertical accuracy of a GDEM is critical for its applications. Nowadays UAVs has been widely used for large-scale surveying and mapping. Compared with traditional surveying techniques, UAV photogrammetry are more convenient and more cost-effective. UAV photogrammetry produces the DEM of the survey area with high accuracy and high spatial resolution. As a result, DEMs resulted from UAV photogrammetry can be used for a more detailed and accurate evaluation of the GDEM product. This study investigates the vertical accuracy (in terms of elevation accuracy and systematic errors) of the ASTER GDEM Version 2 dataset over a complex terrain based on UAV photogrammetry. Experimental results show that the elevation errors of ASTER GDEM2 are in normal distribution and the systematic error is quite small. The accuracy of the ASTER GDEM2 coincides well with that reported by the ASTER validation team. The accuracy in the research area is negatively correlated to both the slope of the terrain and the number of stereo observations. This study also evaluates the vertical accuracy of the up-sampled ASTER GDEM2. Experimental results show that the accuracy of the up-sampled ASTER GDEM2 data in the research area is not significantly reduced by the complexity of the terrain. The fine-grained accuracy evaluation of the ASTER GDEM2 is informative for the GDEM-supported UAV photogrammetric applications.

Monitoring Mountain Meteorology without Much Money (Invited)

NASA Astrophysics Data System (ADS)

Lundquist, J. D.

2009-12-01

Mountains are the water towers of the world, storing winter precipitation in the form of snow until summer, when it can be used for agriculture and cities. However, mountain weather is highly variable, and measurements are sparsely distributed. In order adequately sample snow and climate variables in complex terrain, we need as many measurements as possible. This means that instruments must be inexpensive and relatively simple to deploy. Here, we demonstrate how dime-sized temperature sensors developed for the refrigeration industry can be used to monitor air temperature (using evergreen trees as radiation shields) and snow cover duration (using the diurnal cycle in near-surface soil temperature). Together, these measurements can be used to recreate accumulated snow water equivalent over the prior year. We also demonstrate how buckets of water may be placed under networked acoustic snow depth sensors to provide an index of daily evaporation rates at SNOTEL stations. (a) Temperature sensor sealed for deployment in the soil. (b) Launching a temperature sensor into a tree. (c) Pulley system to keep sensor above the snow. (a) Photo of bucket underneath acoustic snow depth sensor. (b) Water depth in the bucket as calculated by the snow depth sensor and by a pressure sensor inside the bucket.

Landslides susceptibility change over time according to terrain conditions in a mountain area of the tropic region.

PubMed

Pineda, M C; Viloria, J; Martínez-Casasnovas, J A

2016-04-01

Susceptibility to landslides in mountain areas results from the interaction of various factors related to relief formation and soil development. The assessment of landslide susceptibility has generally taken into account individual events, or it has been aimed at establishing relationships between landslide-inventory maps and maps of environmental factors, without considering that such relationships can change in space and time. In this work, temporal and space changes in landslides were analysed in six different combinations of date and geomorphological conditions, including two different geological units, in a mountainous area in the north-centre of Venezuela, in northern South America. Landslide inventories from different years were compared with a number of environmental factors by means of logistic regression analysis. The resulting equations predicted landslide susceptibility from a range of geomorphometric parameters and a vegetation index, with diverse accuracy, in the study area. The variation of the obtained models and their prediction accuracy between geological units and dates suggests that the complexity of the landslide processes and their explanatory factors changed over space and time in the studied area. This calls into question the use of a single model to evaluate landslide susceptibility over large regions.

Stratigraphy of the Descartes region /Apollo 16/ - Implications for the origin of samples

NASA Technical Reports Server (NTRS)

Head, J. W.

1974-01-01

Analysis of terrain in the Apollo 16 Descartes landing region shows a series of features that form a stratigraphic sequence which dominates the history and petrogenesis at the site. An ancient 150-km diam crater centered on the Apollo 16 site is one of the earliest recognizable major structures. Nectaris ejecta was concentrated in a regional low at the base of the back slope of the Nectaris basin to form the Descartes Mountains. Subsequently, a 60-km diam crater formed in the Descartes Mountains centered about 25 km to the west of the site. This crater dominates the geology and petrogenetic history of the site. Stone and Smoky Mountains represent the degraded terraced crater walls, and the dark matrix breccias and metaclastic rocks derived from North and South Ray craters represent floor fallback breccias from this cratering event. The interpretation is developed that the stratigraphy of the Cayley and Descartes, and thus the historical record of the Apollo 16 region, documents the complex interaction of deposits and morphology of local and regional impact cratering events. Large local 60- to 150-km diam craters have had a dramatic and previously unrecognized effect on the history and petrology of the Apollo 16 site.

Snowfall less sensitive to warming in Karakoram than in Himalayas due to a unique seasonal cycle

USGS Publications Warehouse

Kapnick, Sarah B.; Delworth, Thomas L.; Ashfaq, Moetasim; Malyshev, Sergey; Milly, Paul C.D.

2014-01-01

The high mountains of Asia, including the Karakoram, Himalayas and Tibetan Plateau, combine to form a region of perplexing hydroclimate changes. Glaciers have exhibited mass stability or even expansion in the Karakoram region1, 2, 3, contrasting with glacial mass loss across the nearby Himalayas and Tibetan Plateau1, 4, a pattern that has been termed the Karakoram anomaly. However, the remote location, complex terrain and multi-country fabric of high-mountain Asia have made it difficult to maintain longer-term monitoring systems of the meteorological components that may have influenced glacial change. Here we compare a set of high-resolution climate model simulations from 1861 to 2100 with the latest available observations to focus on the distinct seasonal cycles and resulting climate change signatures of Asia’s high-mountain ranges. We find that the Karakoram seasonal cycle is dominated by non-monsoonal winter precipitation, which uniquely protects it from reductions in annual snowfall under climate warming over the twenty-first century. The simulations show that climate change signals are detectable only with long and continuous records, and at specific elevations. Our findings suggest a meteorological mechanism for regional differences in the glacier response to climate warming.

Mountain Heavy Rainfall Measurement Experiments in a Subtropical Monsoon Environment

NASA Astrophysics Data System (ADS)

Jong-Dao Jou, Ben; Chi-June Jung, Ultimate; Lai, Hsiao-Wei; Feng, Lei

2014-05-01

Quantitative rainfall measurement experiments have been conducted in Taiwan area for the past 5 years (since 2008), especially over the complex terrain region. In this paper, results from these experiments will be analyzed and discussed, especially those associated with heavy rain events in the summer monsoon season. Observations from s-band polarimetric radar (SPOL of NCAR) and also x-band vertically-pointing radar are analyzed to reveal the high resolution temporal and spatial variation of precipitation structure. May and June, the Meiyu season in the area, are months with subtropical frontal rainfall events. Mesoscale convective systems, i.e., pre-frontal squall lines and frontal convective rainbands, are very active and frequently produce heavy rain events over mountain areas. Accurate quantitative precipitation measurements are needed in order to meet the requirement for landslide and flood early warning purpose. Using ground-based disdrometers and vertically-pointing radar, we have been trying to modify the quantitative precipitation estimation in the mountain region by using coastal operational radar. In this paper, the methodology applied will be presented and the potential of its application will be discussed. *corresponding author: Ben Jong-Dao Jou, jouben43@gmail.com

A hybrid orographic plus statistical model for downscaling daily precipitation in Northern California

USGS Publications Warehouse

Pandey, G.R.; Cayan, D.R.; Dettinger, M.D.; Georgakakos, K.P.

2000-01-01

A hybrid (physical-statistical) scheme is developed to resolve the finescale distribution of daily precipitation over complex terrain. The scheme generates precipitation by combining information from the upper-air conditions and from sparsely distributed station measurements; thus, it proceeds in two steps. First, an initial estimate of the precipitation is made using a simplified orographic precipitation model. It is a steady-state, multilayer, and two-dimensional model following the concepts of Rhea. The model is driven by the 2.5?? ?? 2.5?? gridded National Oceanic and Atmospheric Administration-National Centers for Environmental Prediction upper-air profiles, and its parameters are tuned using the observed precipitation structure of the region. Precipitation is generated assuming a forced lifting of the air parcels as they cross the mountain barrier following a straight trajectory. Second, the precipitation is adjusted using errors between derived precipitation and observations from nearby sites. The study area covers the northern half of California, including coastal mountains, central valley, and the Sierra Nevada. The model is run for a 5-km rendition of terrain for days of January-March over the period of 1988-95. A jackknife analysis demonstrates the validity of the approach. The spatial and temporal distributions of the simulated precipitation field agree well with the observed precipitation. Further, a mapping of model performance indices (correlation coefficients, model bias, root-mean-square error, and threat scores) from an array of stations from the region indicates that the model performs satisfactorily in resolving daily precipitation at 5-km resolution.

Atmospheric studies in complex terrain: a planning guide for future studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orgill, M.M.

The objective of this study is to assist the US Department of Energy in Conducting its atmospheric studies in complex terrain (ASCOT0 by defining various complex terrain research systems and relating these options to specific landforms sites. This includes: (1) reviewing past meteorological and diffusion research on complex terrain; (2) relating specific terrain-induced airflow phenomena to specific landforms and time and space scales; (3) evaluating the technical difficulty of modeling and measuring terrain-induced airflow phenomena; and (4) avolving severdal research options and proposing candidate sites for continuing and expanding field and modeling work. To evolve research options using variable candidatemore » sites, four areas were considered: site selection, terrain uniqueness and quantification, definition of research problems and research plans. 36 references, 111 figures, 20 tables.« less

Weather observations on Whistler Mountain during five storms

NASA Astrophysics Data System (ADS)

Thériault, Julie M.; Rasmussen, Kristen L.; Fisico, Teresa; Stewart, Ronald E.; Joe, Paul; Gultepe, Ismail; Clément, Marilys; Isaac, George A.

2014-01-01

A greater understanding of precipitation formation processes over complex terrain near the west coast of British Colombia will contribute to many relevant applications, such as climate studies, local hydrology, transportation, and winter sport competition. The phase of precipitation is difficult to determine because of the warm and moist weather conditions experienced during the wintertime in coastal mountain ranges. The goal of this study is to investigate the wide range of meteorological conditions that generated precipitation on Whistler Mountain from 4-12 March 2010 during the SNOW-V10 field campaign. During this time period, five different storms were documented in detail and were associated with noticeably different meteorological conditions in the vicinity of Whistler Mountain. New measurement techniques, along with the SNOW-V10 instrumentation, were used to obtain in situ observations during precipitation events along the Whistler mountainside. The results demonstrate a high variability of weather conditions ranging from the synoptic-scale to the macro-scale. These weather events were associated with a variation of precipitation along the mountainside, such as events associated with snow, snow pellets, and rain. Only two events associated with a rain-snow transition along the mountainside were observed, even though above-freezing temperatures along the mountainside were recorded 90 % of the time. On a smaller scale, these events were also associated with a high variability of snowflake types that were observed simultaneously near the top of Whistler Mountain. Overall, these detailed observations demonstrate the importance of understanding small-scale processes to improve observational techniques, short-term weather prediction, and longer-term climate projections over mountainous regions.

Eddy covariance measurement of CO2 flux to the atmosphere from a area of high volcanogenic emissions, Mammoth Mountain, California

USGS Publications Warehouse

Anderson, D.E.; Farrar, C.D.

2001-01-01

Three pilot studies were performed to assess application of the eddy covariance micrometeorological method in the measurement of carbon dioxide (CO2) flux of volcanic origin. The selected study area is one of high diffuse CO2 emission on Mammoth Mountain, CA. Because terrain and source characteristics make this a complex setting for this type of measurement, added consideration was given to source area and upwind fetch. Footprint analysis suggests that the eddy covariance measurements were representative of an upwind elliptical source area (3.8 ?? 103 m2) which can vary with mean wind direction, surface roughness, and atmospheric stability. CO2 flux averaged 8-16 mg m-2 s-1 (0.7-1.4 kg m-2 day-1). Eddy covariance measurements of flux were compared with surface chamber measurements made in separate studies [Geophys. Res. Lett. 25 (1998a) 1947; EOS Trans. 79 (1998) F941.] and were found to be similar. ?? 2001 Elsevier Science B.V. All rights reserved.

Terrain feature recognition for synthetic aperture radar (SAR) imagery employing spatial attributes of targets

NASA Astrophysics Data System (ADS)

Iisaka, Joji; Sakurai-Amano, Takako

1994-08-01

This paper describes an integrated approach to terrain feature detection and several methods to estimate spatial information from SAR (synthetic aperture radar) imagery. Spatial information of image features as well as spatial association are key elements in terrain feature detection. After applying a small feature preserving despeckling operation, spatial information such as edginess, texture (smoothness), region-likeliness and line-likeness of objects, target sizes, and target shapes were estimated. Then a trapezoid shape fuzzy membership function was assigned to each spatial feature attribute. Fuzzy classification logic was employed to detect terrain features. Terrain features such as urban areas, mountain ridges, lakes and other water bodies as well as vegetated areas were successfully identified from a sub-image of a JERS-1 SAR image. In the course of shape analysis, a quantitative method was developed to classify spatial patterns by expanding a spatial pattern through the use of a series of pattern primitives.

Geomorphic Evolution of Sputnik Planum and Surrounding Terrain

NASA Astrophysics Data System (ADS)

Howard, A. D.; Moore, J. M.; White, O. L.; Umurhan, O. M.; Schenk, P.; Beyer, R. A.; McKinnon, W. B.; Singer, K. N.; Spencer, J. R.; Stern, A.; Weaver, H. A., Jr.; Young, L. A.; Ennico Smith, K.; Olkin, C.

2015-12-01

The informally-named Sputnik Planum is a vast expanse (about 835 km east-west and 1500 km north-south) of N2, CH4, and CO ices which appears craterless at current resolutions, but which gives evidence of both glacial and convective flow in the ices (Stern and the New Horizons Team, Science, 2015). This ice field is surrounded by uplands of varying morphology from hilly terrain to the northeast, plains of apparent ices interspersed with rough terrain to the east, and textured ice surrounding the mountainous terrain to the southwest. The morphology and composition of this bordering terrain will provide clues to the long-term evolution of Sputnik Planum as higher resolution visual and spectral imaging of this region are returned from the New Horizons spacecraft over the next few months. Interactions between Sputnik Planum and surrounding terrain may have involved glacial erosion and deposition. The geomorphic evolution of this region will be discussed in the context of newly-returned encounter data.

Using the SWAT model to improve process descriptions and define hydrologic partitioning in South Korea

NASA Astrophysics Data System (ADS)

Shope, C. L.; Maharjan, G. R.; Tenhunen, J.; Seo, B.; Kim, K.; Riley, J.; Arnhold, S.; Koellner, T.; Ok, Y. S.; Peiffer, S.; Kim, B.; Park, J.-H.; Huwe, B.

2014-02-01

Watershed-scale modeling can be a valuable tool to aid in quantification of water quality and yield; however, several challenges remain. In many watersheds, it is difficult to adequately quantify hydrologic partitioning. Data scarcity is prevalent, accuracy of spatially distributed meteorology is difficult to quantify, forest encroachment and land use issues are common, and surface water and groundwater abstractions substantially modify watershed-based processes. Our objective is to assess the capability of the Soil and Water Assessment Tool (SWAT) model to capture event-based and long-term monsoonal rainfall-runoff processes in complex mountainous terrain. To accomplish this, we developed a unique quality-control, gap-filling algorithm for interpolation of high-frequency meteorological data. We used a novel multi-location, multi-optimization calibration technique to improve estimations of catchment-wide hydrologic partitioning. The interdisciplinary model was calibrated to a unique combination of statistical, hydrologic, and plant growth metrics. Our results indicate scale-dependent sensitivity of hydrologic partitioning and substantial influence of engineered features. The addition of hydrologic and plant growth objective functions identified the importance of culverts in catchment-wide flow distribution. While this study shows the challenges of applying the SWAT model to complex terrain and extreme environments; by incorporating anthropogenic features into modeling scenarios, we can enhance our understanding of the hydroecological impact.

Improvements and Lingering Challenges with Modeling Low-Level Winds Over Complex Terrain during the Wind Forecast Improvement Project 2

NASA Astrophysics Data System (ADS)

Olson, J.; Kenyon, J.; Brown, J. M.; Angevine, W. M.; Marquis, M.; Pichugina, Y. L.; Choukulkar, A.; Bonin, T.; Banta, R. M.; Bianco, L.; Djalalova, I.; McCaffrey, K.; Wilczak, J. M.; Lantz, K. O.; Long, C. N.; Redfern, S.; McCaa, J. R.; Stoelinga, M.; Grimit, E.; Cline, J.; Shaw, W. J.; Lundquist, J. K.; Lundquist, K. A.; Kosovic, B.; Berg, L. K.; Kotamarthi, V. R.; Sharp, J.; Jiménez, P.

2017-12-01

The Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) are NOAA real-time operational hourly updating forecast systems run at 13- and 3-km grid spacing, respectively. Both systems use the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) as the model component of the forecast system. During the second installment of the Wind Forecast Improvement Project (WFIP 2), the RAP/HRRR have been targeted for the improvement of low-level wind forecasts in the complex terrain within the Columbia River Basin (CRB), which requires much finer grid spacing to resolve important terrain peaks in the Cascade Mountains as well as the Columbia River Gorge. Therefore, this project provides a unique opportunity to test and develop the RAP/HRRR physics suite within a very high-resolution nest (Δx = 750 m) over the northwestern US. Special effort is made to incorporate scale-aware aspects into the model physical parameterizations to improve RAP/HRRR wind forecasts for any application at any grid spacing. Many wind profiling and scanning instruments have been deployed in the CRB in support the WFIP 2 field project, which spanned 01 October 2015 to 31 March 2017. During the project, several forecast error modes were identified, such as: (1) too-shallow cold pools during the cool season, which can mix-out more frequently than observed and (2) the low wind speed bias in thermal trough-induced gap flows during the warm season. Development has been focused on the column-based turbulent mixing scheme to improve upon these biases, but investigating the effects of horizontal (and 3D) mixing has also helped improve some of the common forecast failure modes. This presentation will highlight the testing and development of various model components, showing the improvements over original versions for temperature and wind profiles. Examples of case studies and retrospective periods will be presented to illustrate the improvements. We will demonstrate that the improvements made in WFIP 2 will be extendable to other regions, complex or flat terrain. Ongoing and future challenges in RAP/HRRR physics development will be touched upon.

On the effects of scale for ecosystem services mapping

USGS Publications Warehouse

Grêt-Regamey, Adrienne; Weibel, Bettina; Bagstad, Kenneth J.; Ferrari, Marika; Geneletti, Davide; Klug, Hermann; Schirpke, Uta; Tappeiner, Ulrike

2014-01-01

Ecosystems provide life-sustaining services upon which human civilization depends, but their degradation largely continues unabated. Spatially explicit information on ecosystem services (ES) provision is required to better guide decision making, particularly for mountain systems, which are characterized by vertical gradients and isolation with high topographic complexity, making them particularly sensitive to global change. But while spatially explicit ES quantification and valuation allows the identification of areas of abundant or limited supply of and demand for ES, the accuracy and usefulness of the information varies considerably depending on the scale and methods used. Using four case studies from mountainous regions in Europe and the U.S., we quantify information gains and losses when mapping five ES - carbon sequestration, flood regulation, agricultural production, timber harvest, and scenic beauty - at coarse and fine resolution (250 m vs. 25 m in Europe and 300 m vs. 30 m in the U.S.). We analyze the effects of scale on ES estimates and their spatial pattern and show how these effects are related to different ES, terrain structure and model properties. ES estimates differ substantially between the fine and coarse resolution analyses in all case studies and across all services. This scale effect is not equally strong for all ES. We show that spatially explicit information about non-clustered, isolated ES tends to be lost at coarse resolution and against expectation, mainly in less rugged terrain, which calls for finer resolution assessments in such contexts. The effect of terrain ruggedness is also related to model properties such as dependency on land use-land cover data. We close with recommendations for mapping ES to make the resulting maps more comparable, and suggest a four-step approach to address the issue of scale when mapping ES that can deliver information to support ES-based decision making with greater accuracy and reliability.

On the Effects of Scale for Ecosystem Services Mapping

PubMed Central

Grêt-Regamey, Adrienne; Weibel, Bettina; Bagstad, Kenneth J.; Ferrari, Marika; Geneletti, Davide; Klug, Hermann; Schirpke, Uta; Tappeiner, Ulrike

2014-01-01

Ecosystems provide life-sustaining services upon which human civilization depends, but their degradation largely continues unabated. Spatially explicit information on ecosystem services (ES) provision is required to better guide decision making, particularly for mountain systems, which are characterized by vertical gradients and isolation with high topographic complexity, making them particularly sensitive to global change. But while spatially explicit ES quantification and valuation allows the identification of areas of abundant or limited supply of and demand for ES, the accuracy and usefulness of the information varies considerably depending on the scale and methods used. Using four case studies from mountainous regions in Europe and the U.S., we quantify information gains and losses when mapping five ES - carbon sequestration, flood regulation, agricultural production, timber harvest, and scenic beauty - at coarse and fine resolution (250 m vs. 25 m in Europe and 300 m vs. 30 m in the U.S.). We analyze the effects of scale on ES estimates and their spatial pattern and show how these effects are related to different ES, terrain structure and model properties. ES estimates differ substantially between the fine and coarse resolution analyses in all case studies and across all services. This scale effect is not equally strong for all ES. We show that spatially explicit information about non-clustered, isolated ES tends to be lost at coarse resolution and against expectation, mainly in less rugged terrain, which calls for finer resolution assessments in such contexts. The effect of terrain ruggedness is also related to model properties such as dependency on land use-land cover data. We close with recommendations for mapping ES to make the resulting maps more comparable, and suggest a four-step approach to address the issue of scale when mapping ES that can deliver information to support ES-based decision making with greater accuracy and reliability. PMID:25549256

A Case Study of the Mechanisms Modulating the Evolution of Valley Fog

NASA Astrophysics Data System (ADS)

Hang, C.; Nadeau, D. F.; Gultepe, I.; Hoch, S. W.; Román-Cascón, C.; Pryor, K.; Fernando, H. J. S.; Creegan, E. D.; Leo, L. S.; Silver, Z.; Pardyjak, E. R.

2016-09-01

We present a valley fog case study in which radiation fog is modulated by topographic effects using data obtained from a field campaign conducted in Heber Valley, Utah from January 7-February 1, 2015, as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. We use data collected on January 9, 2015 to gain insight into relationships between typical shallow radiation fog, turbulence, and gravity waves associated with the surrounding topography. A ≈ 10-30 m fog layer formed by radiative cooling was observed from 0720 to 0900 MST under cold air temperatures (≈-9 °C), near-saturated (relative humidity with respect to water ≈95 %), and calm wind (mostly <0.5 m s-1) conditions. Drainage flows were observed occasionally prior to fog formation, which modulated heat exchanges between air masses through the action of internal gravity waves and cold-air pool sloshing. The fog appeared to be triggered by cold-air advection from the south (≈200°) at 0700 MST. Quasi-periodic oscillations were observed before and during the fog event with a time period of about 15 min. These oscillations were detected in surface pressure, temperature, sensible heat flux, incoming longwave radiation, and turbulent kinetic energy measurements. We hypothesize that the quasi-periodic oscillations were caused by atmospheric gravity waves with a time period of about 10-20 min based on wavelet analysis. During the fog event, internal gravity waves led to about 1 °C fluctuations in air temperatures. After 0835 MST when net radiation became positive, fog started to dissipate due to the surface heating and heat absorption by the fog particles. Overall, this case study provides a concrete example of how fog evolution is modulated by very weak thermal circulations in mountainous terrain and illustrates the need for high density vertical and horizontal measurements to ensure that the highly spatially varying physics in complex terrain are sufficient for hypothesis testing.

On the effects of scale for ecosystem services mapping.

PubMed

Grêt-Regamey, Adrienne; Weibel, Bettina; Bagstad, Kenneth J; Ferrari, Marika; Geneletti, Davide; Klug, Hermann; Schirpke, Uta; Tappeiner, Ulrike

2014-01-01

Ecosystems provide life-sustaining services upon which human civilization depends, but their degradation largely continues unabated. Spatially explicit information on ecosystem services (ES) provision is required to better guide decision making, particularly for mountain systems, which are characterized by vertical gradients and isolation with high topographic complexity, making them particularly sensitive to global change. But while spatially explicit ES quantification and valuation allows the identification of areas of abundant or limited supply of and demand for ES, the accuracy and usefulness of the information varies considerably depending on the scale and methods used. Using four case studies from mountainous regions in Europe and the U.S., we quantify information gains and losses when mapping five ES - carbon sequestration, flood regulation, agricultural production, timber harvest, and scenic beauty - at coarse and fine resolution (250 m vs. 25 m in Europe and 300 m vs. 30 m in the U.S.). We analyze the effects of scale on ES estimates and their spatial pattern and show how these effects are related to different ES, terrain structure and model properties. ES estimates differ substantially between the fine and coarse resolution analyses in all case studies and across all services. This scale effect is not equally strong for all ES. We show that spatially explicit information about non-clustered, isolated ES tends to be lost at coarse resolution and against expectation, mainly in less rugged terrain, which calls for finer resolution assessments in such contexts. The effect of terrain ruggedness is also related to model properties such as dependency on land use-land cover data. We close with recommendations for mapping ES to make the resulting maps more comparable, and suggest a four-step approach to address the issue of scale when mapping ES that can deliver information to support ES-based decision making with greater accuracy and reliability.

High-resolution LIDAR and ground observations of snow cover in a complex forested terrain in the Sierra Nevada - implications for optical remote sensing of seasonal snow.

NASA Astrophysics Data System (ADS)

Kostadinov, T. S.; Harpold, A.; Hill, R.; McGwire, K.

2017-12-01

Seasonal snow cover is a key component of the hydrologic regime in many regions of the world, especially those in temperate latitudes with mountainous terrain and dry summers. Such regions support large human populations which depend on the mountain snowpack for their water supplies. It is thus important to quantify snow cover accurately and continuously in these regions. Optical remote-sensing methods are able to detect snow and leverage space-borne spectroradiometers with global coverage such as MODIS to produce global snow cover maps. However, snow is harder to detect accurately in mountainous forested terrain, where topography influences retrieval algorithms, and importantly - forest canopies complicate radiative transfer and obfuscate the snow. Current satellite snow cover algorithms assume that fractional snow-covered area (fSCA) under the canopy is the same as the fSCA in the visible portion of the pixel. In-situ observations and first principles considerations indicate otherwise, therefore there is a need for improvement of the under-canopy correction of snow cover. Here, we leverage multiple LIDAR overflights and in-situ observations with a distributed fiber-optic temperature sensor (DTS) to quantify snow cover under canopy as opposed to gap areas at the Sagehen Experimental Forest in the Northern Sierra Nevada, California, USA. Snow-off LIDAR overflights from 2014 are used to create a baseline high-resolution digital elevation model and classify pixels at 1 m resolution as canopy-covered or gap. Low canopy pixels are excluded from the analysis. Snow-on LIDAR overflights conducted by the Airborne Snow Observatory in 2016 are then used to classify all pixels as snow-covered or not and quantify fSCA under canopies vs. in gap areas over the Sagehen watershed. DTS observations are classified as snow-covered or not based on diel temperature fluctuations and used as validation for the LIDAR observations. LIDAR- and DTS-derived fSCA is also compared with retrievals from hyperspectral imaging spectroradiometer (AVIRIS) data. Initial evidence suggest fSCA was generally lower under canopy and that overall snow cover estimates were overestimated as a result. Implications for a canopy correction applicable to coarser-resolution sensors like MODIS are discussed, as are topography and view angle effects.

The landslide hazard in the San Francisco Bay region

USGS Publications Warehouse

Brabb, E.E.

1977-01-01

Development in hilly or mountainous terrain has resulted in much landslide damage. Areas susceptible to landsliding can be recognized. Practices for minimizing landslides are presented. ?? 1977 D. Reidel Publishing Company.

UAS applications in high alpine, snow-covered terrain

NASA Astrophysics Data System (ADS)

Bühler, Y.; Stoffel, A.; Ginzler, C.

2017-12-01

Access to snow-covered, alpine terrain is often difficult and dangerous. Hence parameters such as snow depth or snow avalanche release and deposition zones are hard to map in situ with adequate spatial and temporal resolution and with spatial continuous coverage. These parameters are currently operationally measured at automated weather stations and by observer networks. However such isolated point measurements are not able to capture the information spatial continuous and to describe the high spatial variability present in complex mountain topography. Unmanned Aerial Systems (UAS) have the potential to fill this gap by frequently covering selected high alpine areas with high spatial resolution down to ground resolutions of even few millimeters. At the WSL Institute for Snow and Avalanche Research SLF we test different photogrammetric UAS with visual and near infrared bands. During the last three years we were able to gather experience in more than 100 flight missions in extreme terrain. By processing the imagery applying state-of-the-art structure from motion (SfM) software, we were able to accurately document several avalanche events and to photogrammetrically map snow depth with accuracies from 1 to 20 cm (dependent on the flight height above ground) compare to manual snow probe measurements. This was even possible on homogenous snow surfaces with very little texture. A key issue in alpine terrain is flight planning. We need to cover regions at high elevations with large altitude differences (up to 1 km) with high wind speeds (up to 20 m/s) and cold temperatures (down to - 25°C). Only a few UAS are able to cope with these environmental conditions. We will give an overview on our applications of UAS in high alpine terrain that demonstrate the big potential of such systems to acquire frequent, accurate and high spatial resolution geodata in high alpine, snow covered terrain that could be essential to answer longstanding questions in avalanche and snow hydrology research.

Early-Morning Flow Transition in a Valley in Low-Mountain Terrain Under Clear-Sky Conditions

NASA Astrophysics Data System (ADS)

Brötz, Björn; Eigenmann, Rafael; Dörnbrack, Andreas; Foken, Thomas; Wirth, Volkmar

2014-07-01

We investigate the evolution of the early-morning boundary layer in a low-mountain valley in south-western Germany during COPS (convective and orographically induced precipitation study) in summer 2007. The term low-mountain refers to a mountainous region with a relief of gentle slopes and with an absolute altitude that remains under a specified height (usually 1,500 m a.s.l.). A subset of 23 fair weather days from the campaign was selected to study the transition of the boundary-layer flow in the early morning. The typical valley atmosphere in the morning hours was characterized by a stable temperature stratification and a pronounced valley wind system. During the reversal period—called the low wind period—of the valley wind system (duration of 1-2 h), the horizontal flow was very weak and the conditions for free convection were fulfilled close to the ground. Ground-based sodar observations of the vertical wind show enhanced values of upward motion, and the corresponding statistical properties differ from those observed under windless convective conditions over flat terrain. Large-eddy simulations of the boundary-layer transition in the valley were conducted, and statistical properties of the simulated flow agree with the observed quantities. Spatially coherent turbulence structures are present in the temporal as well as in the ensemble mean analysis. Thus, the complex orography induces coherent convective structures at predictable, specific locations during the early-morning low wind situations. These coherent updrafts, found in both the sodar observations and the simulation, lead to a flux counter to the gradient of the stably stratified valley atmosphere and reach up to the heights of the surrounding ridges. Furthermore, the energy balance in the surface layer during the low wind periods is closed. However, it becomes unclosed after the onset of the valley wind. The partition into the sensible and the latent heat fluxes indicates that missing flux components of sensible heat are the main reason for the unclosed energy balance in the considered situations. This result supports previously published investigations on the energy balance closure.

Thermal preconditioning of mountain permafrost towards instability

NASA Astrophysics Data System (ADS)

Hauck, Christian; Etzelmüller, Bernd; Hilbich, Christin; Isaksen, Ketil; Mollaret, Coline; Pellet, Cécile; Westermann, Sebastian

2017-04-01

Warming permafrost has been detected worldwide in recent years and is projected to continue during the next century as shown in many modelling studies from the polar and mountain regions. In mountain regions, this can lead to potentially hazardous impacts on short time-scales by an increased tendency for slope instabilities. However, the time scale of permafrost thaw and the role of the ice content for determining the strength and rate of permafrost warming and degradation (= development of talik) are still unclear, especially in highly heterogeneous terrain. Observations of permafrost temperatures near the freezing point show complex inter-annual responses to climate forcing due to latent heat effects during thawing and the influence of the snow-cover, which is formed and modulated by highly non-linear processes itself. These effects are complicated by 3-dimensional hydrological processes and interactions between snow melt, infiltration and drainage which may also play an important role in the triggering of mass movements in steep permafrost slopes. In this contribution we demonstrate for the first time a preconditioning effect within near-surface layers in mountain permafrost that causes non-linear degradation and accelerates permafrost thaw. We hypothesise that an extreme regional or global temperature anomaly, such as the Central European summers 2003 and 2015 or the Northern European summers 2006 and 2014, will enhance permafrost degradation if the active layer and the top of the permafrost layer are already preconditioned, i.e. have reduced latent heat content. This preconditioning can already be effectuated by a singular warm year, leading to exceptionally strong melting of the ground ice in the near-surface layers. On sloping terrain and in a context of quasi-continuous atmospheric warming, this ice-loss can be considered as irreversible, as a large part of the melted water will drain/evaporate during the process, and the build-up of an equivalent amount of ice in following cold years does not happen on similar time-scales as the melting. Joint thermal and geophysical observations from permafrost sites in the Swiss Alps and Scandinavia suggest that the above process applies mostly to sites with low to intermediate ice contents, where singular anomalies can lead to sustained ice loss even at larger depths.

Physically-based Canopy Reflectance Model Inversion of Vegetation Biophysical-Structural Information from Terra-MODIS Imagery in Boreal and Mountainous Terrain for Ecosystem, Climate and Carbon Models using the BIOPHYS-MFM Algorithm

NASA Astrophysics Data System (ADS)

Peddle, D. R.; Hall, F.

2009-12-01

The BIOPHYS algorithm provides innovative and flexible methods for the inversion of canopy reflectance models (CRM) to derive essential biophysical structural information (BSI) for quantifying vegetation state and disturbance, and for input to ecosystem, climate and carbon models. Based on spectral, angular, temporal and scene geometry inputs that can be provided or automatically derived, the BIOPHYS Multiple-Forward Mode (MFM) approach generates look-up tables (LUTs) that comprise reflectance data, structural inputs over specified or computed ranges, and the associated CRM output from forward mode runs. Image pixel and model LUT spectral values are then matched. The corresponding BSI retrieved from the LUT matches is output as the BSI results. BIOPHYS-MFM has been extensively used with agencies in Canada and the USA over the past decade (Peddle et al 2000-09; Soenen et al 2005-09; Gamon et al 2004; Cihlar et al 2003), such as CCRS, CFS, AICWR, NASA LEDAPS, BOREAS and MODIS Science Teams, and for the North American Carbon Program. The algorithm generates BSI products such as land cover, biomass, stand volume, stem density, height, crown closure, leaf area index (LAI) and branch area, crown dimension, productivity, topographic correction, structural change from harvest, forest fires and mountain pine beetle damage, and water / hydrology applications. BIOPHYS-MFM has been applied in different locations in Canada (six provinces from Newfoundland to British Columbia) and USA (NASA COVER, MODIS and LEDAPS sites) using 7 different CRM models and a variety of imagery (e.g. MODIS, Landsat, SPOT, IKONOS, airborne MSV, MMR, casi, Probe-1, AISA). In this paper we summarise the BIOPHYS-MFM algorithm and results from Terra-MODIS imagery from MODIS validation sites at Kananaskis Alberta in the Canadian Rocky Mountains, and from the Boreal Ecosystem Atmosphere Study (BOREAS) in Saskatchewan Canada. At the montane Rocky Mountain site, BIOPHYS-MFM density estimates were within ±380 stems/hectare (ha), with horizontal crown radius (HCR) ±0.4m, vertical crown radius (VCR) ±0.6m, and height (HGT) ±0.8m. At the BOREAS site, analysis of single-date MODIS imagery yielded density estimates within ±210 stems/ha, HCR ±0.3m, VCR ±0.5m, and HGT ±0.9m. Higher accuracies at BOREAS compared to the Rocky Mountain site were attributed primarily to the more complex terrain in the mountains, for which good results were obtained given the steep environmental, ecosystem, terrain and biophysical gradients. Further analysis of multiple BOREAS MODIS scenes with different view zenith angles provided convergence of BSI results, with improvements found for density (±42 stems/ha) and HCR (±0.2m). We concluded that good results from MODIS were obtained for both boreal and montane ecosystems. From this and other studies, BIOPHYS-MFM is well suited for large-area, multi-temporal applications involving multiple image sets and mosaics for assessing vegetation disturbance and quantifying vegetation dynamics for carbon and other models. It is also suitable for integration with forest inventory, monitoring and update needs, and other programs.

Characteristics of Forests in Western Sayani Mountains, Siberia from SAR Data

NASA Technical Reports Server (NTRS)

Ranson, K. Jon; Sun, Guoqing; Kharuk, V. I.; Kovacs, Katalin

1998-01-01

This paper investigated the possibility of using spaceborne radar data to map forest types and logging in the mountainous Western Sayani area in Siberia. L and C band HH, HV, and VV polarized images from the Shuttle Imaging Radar-C instrument were used in the study. Techniques to reduce topographic effects in the radar images were investigated. These included radiometric correction using illumination angle inferred from a digital elevation model, and reducing apparent effects of topography through band ratios. Forest classification was performed after terrain correction utilizing typical supervised techniques and principal component analyses. An ancillary data set of local elevations was also used to improve the forest classification. Map accuracy for each technique was estimated for training sites based on Russian forestry maps, satellite imagery and field measurements. The results indicate that it is necessary to correct for topography when attempting to classify forests in mountainous terrain. Radiometric correction based on a DEM (Digital Elevation Model) improved classification results but required reducing the SAR (Synthetic Aperture Radar) resolution to match the DEM. Using ratios of SAR channels that include cross-polarization improved classification and

Predicting forest height using the GOST, Landsat 7 ETM+, and airborne LiDAR for sloping terrains in the Greater Khingan Mountains of China

NASA Astrophysics Data System (ADS)

Gu, Chengyan; Clevers, Jan G. P. W.; Liu, Xiao; Tian, Xin; Li, Zhouyuan; Li, Zengyuan

2018-03-01

Sloping terrain of forests is an overlooked factor in many models simulating the canopy bidirectional reflectance distribution function, which limits the estimation accuracy of forest vertical structure parameters (e.g., forest height). The primary objective of this study was to predict forest height on sloping terrain over large areas with the Geometric-Optical Model for Sloping Terrains (GOST) using airborne Light Detection and Ranging (LiDAR) data and Landsat 7 imagery in the western Greater Khingan Mountains of China. The Sequential Maximum Angle Convex Cone (SMACC) algorithm was used to generate image endmembers and corresponding abundances in Landsat imagery. Then, LiDAR-derived forest metrics, topographical factors and SMACC abundances were used to calibrate and validate the GOST, which aimed to accurately decompose the SMACC mixed forest pixels into sunlit crown, sunlit background and shade components. Finally, the forest height of the study area was retrieved based on a back-propagation neural network and a look-up table. Results showed good performance for coniferous forests on all slopes and at all aspects, with significant coefficients of determination above 0.70 and root mean square errors (RMSEs) between 0.50 m and 1.00 m based on ground observed validation data. Higher RMSEs were found in areas with forest heights below 5 m and above 17 m. For 90% of the forested area, the average RMSE was 3.58 m. Our study demonstrates the tremendous potential of the GOST for quantitative mapping of forest height on sloping terrains with multispectral and LiDAR inputs.

High prevalence of cattle fascioliasis in coastal areas of Thua Thien Hue province, Vietnam

PubMed Central

NGUYEN, Nga Thi; LE, Thinh Cong; VO, Minh Duc Co; VAN CAO, Hoang; NGUYEN, Ly Thi; HO, Khanh Thi; NGUYEN, Quyet Ngoc; TRAN, Vui Quang; MATSUMOTO, Yasunobu

2017-01-01

In Vietnam, especially central Vietnam, patients with fascioliasis are increasingly being reported. Since the fascioliasis is zoonotic, survey on the cattle fascioliasis should be informative for the control of human fascioliasis. In this study, the prevalence of cattle fascioliasis as well as the density of the intermediate host snails, Lymnaea swinhoei and L. viridis, were studied in Thua Thien Hue (TTH) province during 2014–2015. A total of 572 cattle feces were examined from 27 communes in 9 districts. Fasciola eggs were detected in cattle from 24 communes with an average prevalence of 23.4% (134/ 572). The highest prevalence was detected in cattle in the coastal plain terrain (31.0%) followed by plain (25.5%), mountain (21.7%), and low hilly (16.2%) terrains. The highest proportion of heavy infection (>200 EPG) was observed in the coastal plain terrain (36.1%), followed by mountains (20.0%), low hills (13.0%), and plains (8.9%). Low number of heavy infection, as well as relatively low prevalence in low hills and plains were associated with the extensive use of anti-fluke treatments. High number of intermediate host snails in low hilly and plain terrains also indicate high risk of fascioliasis. In this study, the density of Lymnaea snails in the coastal plain terrain was found to be very high (17.3 snails/m2) compared to that in previous studies. This is the first report indicating the recent expansion of cattle fascioliasis in the coastal region in Vietnam. PMID:28458272

Inclinometer--time-domain reflectometry comparative study : executive summary report.

DOT National Transportation Integrated Search

2004-10-01

Slope stability is an ongoing issue in : hilly or mountainous terrains with clay : rich soil, constructed embankments, : fluctuating temperature, and changing : soil moisture conditions. Landslides : constitute a major geologic hazard, : occurring in...

Inclinometer - Time Domain Reflectometry Comparative Study : Executive Summary Report

DOT National Transportation Integrated Search

2004-10-01

Slope stability is an ongoing issue in : hilly or mountainous terrains with clay : rich soil, constructed embankments, : fluctuating temperature, and changing : soil moisture conditions. Landslides : constitute a major geologic hazard, : occurring in...

Western USA

Atmospheric Science Data Center

2014-05-15

... Terrain Elevation Model from the United States Geological Survey. Among the prominent features are the snow-capped Rocky Mountains ... is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, ...

Numerical simulation of terrain-induced mesoscale circulation in the Chiang Mai area, Thailand

NASA Astrophysics Data System (ADS)

Sathitkunarat, Surachai; Wongwises, Prungchan; Pan-Aram, Rudklao; Zhang, Meigen

2008-11-01

The regional atmospheric modeling system (RAMS) was applied to Chiang Mai province, a mountainous area in Thailand, to study terrain-induced mesoscale circulations. Eight cases in wet and dry seasons under different weather conditions were analyzed to show thermal and dynamic impacts on local circulations. This is the first study of RAMS in Thailand especially investigating the effect of mountainous area on the simulated meteorological data. Analysis of model results indicates that the model can reproduce major features of local circulation and diurnal variations in temperatures. For evaluating the model performance, model results were compared with observed wind speed, wind direction, and temperature monitored at a meteorological tower. Comparison shows that the modeled values are generally in good agreement with observations and that the model captured many of the observed features.

Even between-lap pacing despite high within-lap variation during mountain biking.

PubMed

Martin, Louise; Lambeth-Mansell, Anneliese; Beretta-Azevedo, Liane; Holmes, Lucy A; Wright, Rachel; St Clair Gibson, Alan

2012-09-01

Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain. A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean±SD age=27.2±5.0 y, stature=176.8±8.1 cm, mass=76.3±11.7 kg, VO2max=55.1±6.0 mL·kg(-1)·min1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation. There was no significant difference in lap times (P=.99) or lap velocity (P=.65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain. Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise.

Debris-flow initiation from large, slow-moving landslides

USGS Publications Warehouse

Reid, M.E.; Brien, D.L.; LaHusen, R.G.; Roering, J.J.; de la Fuente, J.; Ellen, S.D.; ,

2003-01-01

In some mountainous terrain, debris flows preferentially initiate from the toes and margins of larger, deeper, slower-moving landslides. During the wet winter of 1997, we began real-time monitoring of the large, active Cleveland Corral landslide complex in California, USA. When the main slide is actively moving, small, shallow, first-time slides on the toe and margins mobilize into debris flows and travel down adjacent gullies. We monitored the acceleration of one such failure; changes in velocity provided precursory indications of rapid failure. Three factors appear to aid the initiation of debris flows at this site: 1) locally steepened ground created by dynamic landslide movement, 2) elevated pore-water pressures and abundant soil moisture, and 3) locally cracked and dilated materials. This association between debris flows and large landslides can be widespread in some terrain. Detailed photographic mapping in two watersheds of northwestern California illustrates that the areal density of debris-flow source landsliding is about 3 to 7 times greater in steep geomorphically fresher landslide deposits than in steep ground outside landslide deposits. ?? 2003 Millpress.

Numerical simulation of distributed snow processes in complex terrain utilizing triangulated irregular networks (TINs)

NASA Astrophysics Data System (ADS)

Rinehart, A. J.; Vivoni, E. R.

2005-12-01

Snow processes play a significant role in the hydrologic cycle of mountainous and high-latitude catchments in the western United States. Snowmelt runoff contributes to a large percentage of stream runoff while snow covered regions remain highly localized to small portions of the catchment area. The appropriate representation of snow dynamics at a given range of spatial and temporal scales is critical for adequately predicting runoff responses in snowmelt-dominated watersheds. In particular, the accurate depiction of snow cover patterns is important as a range of topographic, land-use and geographic parameters create zones of preferential snow accumulation or ablation that significantly affect the timing of a region's snow melt and the persistence of a snow pack. In this study, we present the development and testing of a distributed snow model designed for simulations over complex terrain. The snow model is developed within the context of the TIN-based Real-time Integrated Basin Simulator (tRIBS), a fully-distributed watershed model capable of continuous simulations of coupled hydrological processes, including unsaturated-saturated zone dynamics, land-atmosphere interactions and runoff generation via multiple mechanisms. The use of triangulated irregular networks as a domain discretization allows tRIBS to accurately represent topography with a reduced number of computational nodes, as compared to traditional grid-based models. This representation is developed using a Delauney optimization criterion that causes areas of topographic homogeneity to be represented at larger spatial scales than the original grid, while more heterogeneous areas are represented at higher resolutions. We utilize the TIN-based terrain representation to simulate microscale (10-m to 100-m) snow pack dynamics over a catchment. The model includes processes such as the snow pack energy balance, wind and bulk redistribution, and snow interception by vegetation. For this study, we present tests from a distributed one-layer energy balance model as applied to a northern New Mexico hillslope in a ponderosa pine forest using both synthetic and real meteorological forcing. We also provide tests of the model's capability to represent spatial patterns within a small watershed in the Jemez Mountain region. Finally, we discuss the interaction of the tested snow process module with existing components in the watershed model and additional applications and capabilities under development.

The influence of terrain forcing on the initiation of deep convection over Mediterranean islands

NASA Astrophysics Data System (ADS)

Barthlott, Christian; Kirshbaum, Daniel

2013-04-01

The influence of mountainous islands on the initiation of deep convection is investigated using the Consortium for Small-scale Modeling (COSMO) model. The study day is 26 August 2009 on which moist convection occurred over both the Corsica and Sardinia island in the Mediterranean Sea. Sensitivity runs with systematically modified topography are explored to evaluate the relative importance of the land-sea contrast and the terrain height for convection initiation. Whereas no island precipitation is simulated when the islands are completely removed, all simulations that represent these land surfaces develop convective precipitation. Although convection initiates progressively earlier in the day over taller islands, the precipitation rates and accumulations do not show a fixed relationship with terrain height. This is due to the competing effects of different physical processes. First, whereas the forcing for low-level ascent increases over taller islands, the boundary-layer moisture supply decreases, which diminishes the conditional instability and precipitable water. Second, whereas taller islands enhance the inland propagation speeds of sea-breeze fronts, they also mechanically block these fronts and prevent them from reaching the island interior. As a result, the island precipitation is rather insensitive to island terrain height except for one particular case in which the island precipitation increases considerably due to an optimal superposition of the sea breeze and upslope flow. These results demonstrate the complexity of interactions between sea breezes and orography and reinforce that an adequate representation of detailed topographic features is necessary to account for thermally induced wind systems that initiate deep convection.

Topographic forcing and related uncertainties on glacier surface energy balance in High Mountain Asia

NASA Astrophysics Data System (ADS)

Olson, M.; Rupper, S.; Shean, D. E.

2017-12-01

Topography directly influences the amount of global radiation, as well as other key energy flux terms, arriving on a glacier surface. This is particularly important in regions of variable and complex topography such as High Mountain Asia (HMA). In this region surface energy and mass balance estimates often rely heavily on modeling, and thus require accurate accounting of topography through available remote sensing platforms. Our previous work shows that topographic shading from surrounding terrain can alter the mean daily potential direct shortwave radiation by upwards of 20% for some valley glaciers. In this work, we find in regions of high topographic relief that shading frequently dominates in the ablation zone rather than the accumulation zone, contrary to the findings of some previous studies. This however, is largely dependent on the valley aspect and relative relief of nearby terrain. In addition, we examine the impact of topography, primarily topographic shading, on components of surface energy balance for a large sample of glaciers across different regions in HMA. Our results show that while the impact of topographic shading is highly variable throughout HMA, the magnitude of influence can often be predicted based on simple characteristics such as latitude, valley aspect, and orientation of the immediate surrounding topography. We also explore the uncertainty in topographic shading and in calculated surface energy due to the spatial resolution and accuracy of DEMs. In particular, we compare the shading and energy balance results utilizing a suite of DEMs, including 2 m, 8 m, and 30 m World View DEMs, 30 m ASTER GDEM, 30 m SRTM DEM, and 30 m ALOS DEM. These results will help us improve glacier energy and mass balance modeling accuracy, and demonstrate limitations and uncertainties when modeling changes in surface energy fluxes due to surrounding topography for mountain glaciers.

Distribution and interplay of geologic processes on Titan from Cassini radar data

USGS Publications Warehouse

Lopes, R.M.C.; Stofan, E.R.; Peckyno, R.; Radebaugh, J.; Mitchell, K.L.; Mitri, Giuseppe; Wood, C.A.; Kirk, R.L.; Wall, S.D.; Lunine, J.I.; Hayes, A.; Lorenz, R.; Farr, Tom; Wye, L.; Craig, J.; Ollerenshaw, R.J.; Janssen, M.; LeGall, A.; Paganelli, F.; West, R.; Stiles, B.; Callahan, P.; Anderson, Y.; Valora, P.; Soderblom, L.

2010-01-01

The Cassini Titan Radar Mapper is providing an unprecedented view of Titan's surface geology. Here we use Synthetic Aperture Radar (SAR) image swaths (Ta-T30) obtained from October 2004 to December 2007 to infer the geologic processes that have shaped Titan's surface. These SAR swaths cover about 20% of the surface, at a spatial resolution ranging from ???350 m to ???2 km. The SAR data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth - volcanism, tectonism, impact cratering, and erosion and deposition by fluvial and aeolian activity. In this paper, we map geomorphological units from SAR data and analyze their areal distribution and relative ages of modification in order to infer the geologic evolution of Titan's surface. We find that dunes and hummocky and mountainous terrains are more widespread than lakes, putative cryovolcanic features, mottled plains, and craters and crateriform structures that may be due to impact. Undifferentiated plains are the largest areal unit; their origin is uncertain. In terms of latitudinal distribution, dunes and hummocky and mountainous terrains are located mostly at low latitudes (less than 30??), with no dunes being present above 60??. Channels formed by fluvial activity are present at all latitudes, but lakes are at high latitudes only. Crateriform structures that may have been formed by impact appear to be uniformly distributed with latitude, but the well-preserved impact craters are all located at low latitudes, possibly indicating that more resurfacing has occurred at higher latitudes. Cryovolcanic features are not ubiquitous, and are mostly located between 30?? and 60?? north. We examine temporal relationships between units wherever possible, and conclude that aeolian and fluvial/pluvial/lacustrine processes are the most recent, while tectonic processes that led to the formation of mountains and Xanadu are likely the most ancient. ?? 2009 Elsevier Inc.

Disribution and interplay of geologic processes on Titan from Cassini radar data

USGS Publications Warehouse

Lopes, R.M.C.; Stofan, E.R.; Peckyno, R.; Radebaugh, J.; Mitchell, K.L.; Mitri, Giuseppe; Wood, C.A.; Kirk, R.L.; Wall, S.D.; Lunine, J.I.; Hayes, A.; Lorenz, R.; Farr, Tom; Wye, L.; Craig, J.; Ollerenshaw, R.J.; Janssen, M.; LeGall, A.; Paganelli, F.; West, R.; Stiles, B.; Callahan, P.; Anderson, Y.; Valora, P.; Soderblom, L.

2010-01-01

The Cassini Titan Radar Mapper is providing an unprecedented view of Titan's surface geology. Here we use Synthetic Aperture Radar (SAR) image swaths (Ta-T30) obtained from October 2004 to December 2007 to infer the geologic processes that have shaped Titan's surface. These SAR swaths cover about 20% of the surface, at a spatial resolution ranging from ~350 m to ~2 km. The SAR data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth - volcanism, tectonism, impact cratering, and erosion and deposition by fluvial and aeolian activity. In this paper, we map geomorphological units from SAR data and analyze their areal distribution and relative ages of modification in order to infer the geologic evolution of Titan's surface. We find that dunes and hummocky and mountainous terrains are more widespread than lakes, putative cryovolcanic features, mottled plains, and craters and crateriform structures that may be due to impact. Undifferentiated plains are the largest areal unit; their origin is uncertain. In terms of latitudinal distribution, dunes and hummocky and mountainous terrains are located mostly at low latitudes (less than 30 degrees), with no dunes being present above 60 degrees. Channels formed by fluvial activity are present at all latitudes, but lakes are at high latitudes only. Crateriform structures that may have been formed by impact appear to be uniformly distributed with latitude, but the well-preserved impact craters are all located at low latitudes, possibly indicating that more resurfacing has occurred at higher latitudes. Cryovolcanic features are not ubiquitous, and are mostly located between 30 degrees and 60 degrees north. We examine temporal relationships between units wherever possible, and conclude that aeolian and fluvial/pluvial/lacustrine processes are the most recent, while tectonic processes that led to the formation of mountains and Xanadu are likely the most ancient.

Incoming longwave radiation to melting snow: observations, sensitivity and estimation in Northern environments

NASA Astrophysics Data System (ADS)

Sicart, J. E.; Pomeroy, J. W.; Essery, R. L. H.; Bewley, D.

2006-11-01

At high latitudes, longwave radiation can provide similar, or higher, amounts of energy to snow than shortwave radiation due to the low solar elevation (cosine effect and increased scattering due to long atmospheric path lengths). This effect is magnified in mountains due to shading and longwave emissions from the complex topography. This study examines longwave irradiance at the snow surface in the Wolf Creek Research Basin, Yukon Territory, Canada (60° 36N, 134° 57W) during the springs of 2002 and 2004. Incoming longwave radiation was estimated from standard meteorological measurements by segregating radiation sources into clear sky, clouds and surrounding terrain. A sensitivity study was conducted to detect the atmospheric and topographic conditions under which emission from adjacent terrain significantly increases the longwave irradiance. The total incoming longwave radiation is more sensitive to sky view factor than to the temperature of the emitting terrain surfaces. Brutsaert's equation correctly simulates the clear-sky irradiance for hourly time steps using temperature and humidity. Longwave emissions from clouds, which raised longwave radiation above that from clear skies by 16% on average, were best estimated using daily atmospheric shortwave transmissivity and hourly relative humidity. An independent test of the estimation procedure for a prairie site near Saskatoon, Saskatchewan, Canada, indicated that the calculations are robust in late winter and spring conditions. Copyright

Basin Hydrology and Substrate Controls on Mountain Stream Morphology: Highlands of Southeastern West Virginia

NASA Astrophysics Data System (ADS)

Burks, T. W.; Springer, G. S.

2004-12-01

Evolution of mountain drainage basins across a broad spectrum of geologic, tectonic, and climatic conditions is an active area of investigation in the field of fluvial geomorphology. Mountain streams are typified by steep channel gradients (>0.002), high channel roughness, rapid changes in drainage area, and high spatial and low temporal variability in channel morphology, leading to complexities in landscape modeling relative to their lowland counterparts. Factors driving this recent investigative trend are the refinement and generation of digital topographic data and terrain analysis software, and more importantly, the demand for a multidiscipline approach to the assessment, restoration, and management of entire watersheds. A significant volume of research has been conducted in mountain drainage basins of the western United States, with particular attention paid to tectonically active regions of the Pacific Northwest, which also contain federally listed threatened and endangered salmonid populations. Brook trout (Salvelinus fontinalis), native to the highlands of the eastern margin of the Appalachian Plateau are impacted by acid rain deposition; however, geomorphic research into landscape modeling, applicable to restoration and management of lotic ecosystems of the eastern United States, is comparatively lacking. This current research explores the potential for modeling channel morphology in mountain streams; specifically, how downstream trends in channel substrate resistance and unit stream power effect the partitioning of mountain stream morphology along and downstream of the fluvial/colluvial transition. In order to address this issue, two mountain drainage basins in the headwaters of the Gauley River watershed on the Appalachian Plateau of southeastern West Virginia were chosen. The westerly flowing Cranberry (250 sqkm) and Cherry (429 sqkm) rivers incise gently northwestward dipping Carboniferous-aged strata (shale, minor coal, siltstone, sandstone, and conglomerate), with a large percentage of both drainages managed as the Monongahela National Forest. A total of 68 reach-scale (10-20 channel widths) channel surveys were completed in which reach gradient, average bankfull channel widths, and bed surface grain size data were determined. This information was synthesized with data extracted from 10-meter digital elevation models using both RiverTools v. 2.4 and ArcGIS Desktop 8.3 terrain analysis software packages. Surveyed channel reach gradients range from (0.002-0.150 m/m) and are characterized by pool-riffle to cascade and step-pool morphologies, though observed morphology succession is atypical of an equilibrated system. Partitioning in channel morphology succession correlates with both changes in lithology (e.g. siltstone to conglomerate) and the extent of headwater debris flow activity, which reflects a shift in the balance between driving and resisting forces as stream size increases.

Testing and evaluation of a wearable augmented reality system for natural outdoor environments

NASA Astrophysics Data System (ADS)

Roberts, David; Menozzi, Alberico; Cook, James; Sherrill, Todd; Snarski, Stephen; Russler, Pat; Clipp, Brian; Karl, Robert; Wenger, Eric; Bennett, Matthew; Mauger, Jennifer; Church, William; Towles, Herman; MacCabe, Stephen; Webb, Jeffrey; Lupo, Jasper; Frahm, Jan-Michael; Dunn, Enrique; Leslie, Christopher; Welch, Greg

2013-05-01

This paper describes performance evaluation of a wearable augmented reality system for natural outdoor environments. Applied Research Associates (ARA), as prime integrator on the DARPA ULTRA-Vis (Urban Leader Tactical, Response, Awareness, and Visualization) program, is developing a soldier-worn system to provide intuitive `heads-up' visualization of tactically-relevant geo-registered icons. Our system combines a novel pose estimation capability, a helmet-mounted see-through display, and a wearable processing unit to accurately overlay geo-registered iconography (e.g., navigation waypoints, sensor points of interest, blue forces, aircraft) on the soldier's view of reality. We achieve accurate pose estimation through fusion of inertial, magnetic, GPS, terrain data, and computer-vision inputs. We leverage a helmet-mounted camera and custom computer vision algorithms to provide terrain-based measurements of absolute orientation (i.e., orientation of the helmet with respect to the earth). These orientation measurements, which leverage mountainous terrain horizon geometry and mission planning landmarks, enable our system to operate robustly in the presence of external and body-worn magnetic disturbances. Current field testing activities across a variety of mountainous environments indicate that we can achieve high icon geo-registration accuracy (<10mrad) using these vision-based methods.

Wind turbine wake measurement in complex terrain

NASA Astrophysics Data System (ADS)

Hansen, KS; Larsen, GC; Menke, R.; Vasiljevic, N.; Angelou, N.; Feng, J.; Zhu, WJ; Vignaroli, A.; W, W. Liu; Xu, C.; Shen, WZ

2016-09-01

SCADA data from a wind farm and high frequency time series measurements obtained with remote scanning systems have been analysed with focus on identification of wind turbine wake properties in complex terrain. The analysis indicates that within the flow regime characterized by medium to large downstream distances (more than 5 diameters) from the wake generating turbine, the wake changes according to local atmospheric conditions e.g. vertical wind speed. In very complex terrain the wake effects are often “overruled” by distortion effects due to the terrain complexity or topology.

Spatiotemporal patterns of precipitation inferred from streamflow observations across the Sierra Nevada mountain range

NASA Astrophysics Data System (ADS)

Henn, Brian; Clark, Martyn P.; Kavetski, Dmitri; Newman, Andrew J.; Hughes, Mimi; McGurk, Bruce; Lundquist, Jessica D.

2018-01-01

Given uncertainty in precipitation gauge-based gridded datasets over complex terrain, we use multiple streamflow observations as an additional source of information about precipitation, in order to identify spatial and temporal differences between a gridded precipitation dataset and precipitation inferred from streamflow. We test whether gridded datasets capture across-crest and regional spatial patterns of variability, as well as year-to-year variability and trends in precipitation, in comparison to precipitation inferred from streamflow. We use a Bayesian model calibration routine with multiple lumped hydrologic model structures to infer the most likely basin-mean, water-year total precipitation for 56 basins with long-term (>30 year) streamflow records in the Sierra Nevada mountain range of California. We compare basin-mean precipitation derived from this approach with basin-mean precipitation from a precipitation gauge-based, 1/16° gridded dataset that has been used to simulate and evaluate trends in Western United States streamflow and snowpack over the 20th century. We find that the long-term average spatial patterns differ: in particular, there is less precipitation in the gridded dataset in higher-elevation basins whose aspect faces prevailing cool-season winds, as compared to precipitation inferred from streamflow. In a few years and basins, there is less gridded precipitation than there is observed streamflow. Lower-elevation, southern, and east-of-crest basins show better agreement between gridded and inferred precipitation. Implied actual evapotranspiration (calculated as precipitation minus streamflow) then also varies between the streamflow-based estimates and the gridded dataset. Absolute uncertainty in precipitation inferred from streamflow is substantial, but the signal of basin-to-basin and year-to-year differences are likely more robust. The findings suggest that considering streamflow when spatially distributing precipitation in complex terrain may improve its representation, particularly for basins whose orientations (e.g., windward-facing) are favored for orographic precipitation enhancement.

Development of improved wildfire smoke exposure estimates for health studies in the western U.S.

NASA Astrophysics Data System (ADS)

Ivey, C.; Holmes, H.; Loria Salazar, S. M.; Pierce, A.; Liu, C.

2016-12-01

Wildfire smoke exposure is a significant health concern in the western U.S. because large wildfires have increased in size and frequency over the past four years due to drought conditions. The transport phenomena in complex terrain and timing of the wildfire emissions make the smoke plumes difficult to simulate using conventional air quality models. Monitoring data can be used to estimate exposure metrics, but in rural areas the monitoring networks are too sparse to calculate wildfire exposure metrics for the entire population in a region. Satellite retrievals provide global, spatiotemporal air quality information and are used to track pollution plumes, estimate human exposures, model emissions, and determine sources (i.e., natural versus anthropogenic) in regulatory applications. Particulate matter (PM) exposures can be estimated using columnar aerosol optical depth (AOD), where satellite AOD retrievals serve as a spatial surrogate to simulate surface PM gradients. These exposure models have been successfully used in health effects studies in the eastern U.S. where complex mountainous terrain and surface reflectance do not limit AOD retrival from satellites. Using results from a chemical transport model (CTM) is another effective method to determine spatial gradients of pollutants. However, the CTM does not adequately capture the temporal and spatial distribution of wildfire smoke plumes. By combining the spatiotemporal pollutant fields from both satellite retrievals and CTM results with ground based pollutant observations the spatial wildfire smoke exposure model can be improved. This work will address the challenge of understanding the spatiotemporal distributions of pollutant concentrations to model human exposures of wildfire smoke in regions with complex terrain, where meteorological conditions as well as emission sources significantly influence the spatial distribution of pollutants. The focus will be on developing models to enhance exposure estimates of elevated PM and ozone concentrations from wildfire smoke plumes in the western U.S.

An improved export coefficient model to estimate non-point source phosphorus pollution risks under complex precipitation and terrain conditions.

PubMed

Cheng, Xian; Chen, Liding; Sun, Ranhao; Jing, Yongcai

2018-05-15

To control non-point source (NPS) pollution, it is important to estimate NPS pollution exports and identify sources of pollution. Precipitation and terrain have large impacts on the export and transport of NPS pollutants. We established an improved export coefficient model (IECM) to estimate the amount of agricultural and rural NPS total phosphorus (TP) exported from the Luanhe River Basin (LRB) in northern China. The TP concentrations of rivers from 35 selected catchments in the LRB were used to test the model's explanation capacity and accuracy. The simulation results showed that, in 2013, the average TP export was 57.20 t at the catchment scale. The mean TP export intensity in the LRB was 289.40 kg/km 2 , which was much higher than those of other basins in China. In the LRB topographic regions, the TP export intensity was the highest in the south Yanshan Mountains and was followed by the plain area, the north Yanshan Mountains, and the Bashang Plateau. Among the three pollution categories, the contribution ratios to TP export were, from high to low, the rural population (59.44%), livestock husbandry (22.24%), and land-use types (18.32%). Among all ten pollution sources, the contribution ratios from the rural population (59.44%), pigs (14.40%), and arable land (10.52%) ranked as the top three sources. This study provides information that decision makers and planners can use to develop sustainable measures for the prevention and control of NPS pollution in semi-arid regions.

Last Glacial-Interglacial Transition ice dynamics in the Wicklow Mountains, Ireland

NASA Astrophysics Data System (ADS)

Knight, Lauren; Boston, Clare; Lovell, Harold; Pepin, Nick

2017-04-01

Understanding of the extent and dynamics of former ice masses in the Wicklow Mountains, Ireland, during the Last Glacial-Interglacial Transition (LGIT; 15-10 ka BP) is currently unresolved. Whilst it is acknowledged that the region hosted a local ice cap within the larger British-Irish Ice Sheet at the Last Glacial Maximum (LGM; 27 ka BP), there has been little consideration of ice cap disintegration to a topographically constrained ice mass during the LGIT. This research has produced the first regional glacial geomorphological map, through remote sensing (aerial photograph and digital terrain model interrogation) and field mapping. This has allowed both the style and extent of mountain glaciation and ice recession dynamics during the LGIT to be established. This geomorphological mapping has highlighted that evidence for local glaciation in the Wicklow Mountains is more extensive than previously recognised, and that small icefields and associated outlet valley glaciers existed during the LGIT following disintegration of the Wicklow Ice Cap. A relative chronology based on morphostratigraphic principles is developed, which indicates complex patterns of ice mass oscillation characterised by periods of both sustained retreat and minor readvance. Variations in the pattern of recession across the Wicklow Mountains are evident and appear to be influenced, in part, by topographic controls (e.g. slope, aspect, glacier hypsometry). In summary, this research establishes a relative chronology of glacial events in the region during the LGIT and presents constraints on ice mass extent, dynamics and retreat patterns, offering an insight into small ice mass behaviour in a warming climate.

Design and flight evaluation of an integrated navigation and near-terrain helicopter guidance system for night-time and adverse weather operations

NASA Technical Reports Server (NTRS)

Swenson, Harry N.; Zelenka, Richard E.; Dearing, Munro G.; Hardy, Gordon H.; Clark, Raymond; Davis, Tom; Amatrudo, Gary; Zirkler, Andre

1994-01-01

NASA and the U.S. Army have designed, developed, and flight evaluated a Computer Aiding for Low Altitude Helicopter Flight (CALAHF) guidance system. This system provides guidance to the pilot for near terrain covert helicopter operations. It automates the processing of precision navigation information, helicopter mission requirements, and terrain flight guidance. The automation is presented to the pilot through symbology on a helmet-mounted display. The symbology is a 'pilot-centered' design which preserves pilot flexibility and authority over the CALAHF system's automation. An extensive flight evaluation of the system has been conducted using the U.S. Army's NUH-60 STAR (Systems Testbed for Avionics Research) research helicopter. The evaluations were flown over a multiwaypoint helicopter mission in rugged mountainous terrain, at terrain clearance altitudes from 300 to 125 ft and airspeeds from 40 to 110 knots. The results of these evaluations showed that the pilots could precisely follow the automation symbology while maintaining a high degree of situational awareness.

Groundwater resources vulnerability due to melting glaciers in the Talgar alluvian fan, northern Tien-Shan

NASA Astrophysics Data System (ADS)

Saks, Tomas; Timuhins, Andrejs; Sennikovs, Juris; Ibraimov, Vitaliy; Sotnikov, Evgeniy; Salybekova, Valentina; Rahimov, Timur; Popovs, Konrads

2017-04-01

Alluvial fans on the mountain slopes in Central Asia are an important source of the groundwater, due to there capacity of storing large quantities of the fresh groundwater and due to the fact that most urban centres are situated in the mountainous terrain or along mountain slopes. The groundwater resources in the alluvial fans are replenished by the infiltration from the rivers, which drain the mountain catchments and by infiltration from the precipitation, and released on there lower reaches as a series of seasonal springs or infiltrated into the lower lying aquifers. The rivers with there catchments in the mountainous terrain are fed by the precipitation (with the peak in May-June due to snow melt) and glacier melt. The glacier meltwater constitutes up to 90% of the river runoff in July-August, due to peak in glacier melt and low precipitation, providing much needed freshwater for agriculture in the dry season. In this study an attempt to quantify the importance of the glacier meltwater on the groundwater resources through groundwater modelling in the Talgar alluvial fan, Ili-Alatau mountain range has been performed. The results suggest that glacier meltwater is a substantial portion of the groundwater resources in the Talgar alluvial fan, with up to 30m drop of the groundwater level, if the glaciers disappear, endangering existing groundwater supply. The transient simulations suggest that disappearance of the glaciers and highly variable annual precipitation would result in highly fluctuating groundwater levels, as well as disappearance of most of the springs at the foot of the alluvial fan. These results are especially relevant for the northern Tien-Shan, where glaciers have been rapidly retreating over last 50 years, and some of the glaciers could disappear in next decades.

OLYMPEX Data Workshop: GPM View

NASA Technical Reports Server (NTRS)

Petersen, W.

2017-01-01

OLYMPEX Primary Objectives: Datasets to enable: (1) Direct validation over complex terrain at multiple scales, liquid and frozen precip types, (a) Do we capture terrain and synoptic regime transitions, orographic enhancements/structure, full range of precipitation intensity (e.g., very light to heavy) and types, spatial variability? (b) How well can we estimate space/time-accumulated precipitation over terrain (liquid + frozen)? (2) Physical validation of algorithms in mid-latitude cold season frontal systems over ocean and complex terrain, (a) What are the column properties of frozen, melting, liquid hydrometeors-their relative contributions to estimated surface precipitation, transition under the influence of terrain gradients, and systematic variability as a function of synoptic regime? (3) Integrated hydrologic validation in complex terrain, (a) Can satellite estimates be combined with modeling over complex topography to drive improved products (assimilation, downscaling) [Level IV products] (b) What are capabilities and limitations for use of satellite-based precipitation estimates in stream/river flow forecasting?

Post-fire, rainfall intensity-peak discharge relations for three mountainous watersheds in the Western USA

USGS Publications Warehouse

Moody, J.A.; Martin, D.A.

2001-01-01

Wildfire alters the hydrologic response of watersheds, including the peak discharges resulting from subsequent rainfall. Improving predictions of the magnitude of flooding that follows wildfire is needed because of the increase in human population at risk in the wildland-urban interface. Because this wildland-urban interface is typically in mountainous terrain, we investigated rainfall-runoff relations by measuring the maximum 30 min rainfall intensity and the unit-area peak discharge (peak discharge divided by the area burned) in three mountainous watersheds (17-26.8 km2) after a wildfire. We found rainfall-runoff relations that relate the unit-area peak discharges to the maximum 30 min rainfall intensities by a power law. These rainfall-runoff relations appear to have a threshold value for the maximum 30 min rainfall intensity (around 10 mm h-1) such that, above this threshold, the magnitude of the flood peaks increases more rapidly with increases in intensity. This rainfall intensity could be used to set threshold limits in rain gauges that are part of an early-warning flood system after wildfire. The maximum unit-area peak discharges from these three burned watersheds ranged from 3.2 to 50 m3 s-1 km-2. These values could provide initial estimates of the upper limits of runoff that can be used to predict floods after wildfires in mountainous terrain. Published in 2001 by John Wiley and Sons, Ltd.

Train Generated Air Contaminants in the Train Crew's Working Environment

DOT National Transportation Integrated Search

1977-02-01

This document contains data on the levels of air contaminants in the train crew's working environment. Measurements were made in locomotive cabs and cabooses of freight trains travelling through long tunnels and over mountainous terrain. In addition,...

The importance of topographic corrections on magnetotelluric response data from rugged regions of Anatolia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerer, A.; Ilkisik, O.M.

1997-01-01

Topographic irregularities cause some distortions of magnetotelluric (MT) fields. In the vicinity of a topographic feature, the TM-mode distortion increases with the height and inclination of the slope. It is well-known that TM-mode topographic effects are much greater than TE-mode distortions. The authors have made a study of MT anomalies in TM-mode due to two-dimensional topography. In order to reduce these effects, the distortion tensor stripping technique was used. After corrections, the resulting data can be interpreted as if they were obtained over a flat surface and depend only on the subsurface structure. However, this technique sometimes causes some geometricalmore » distortions of the real subsurface structure. One of the aims is to overcome this failure. The authors have modified the correction coefficients by considering the actual one-dimensional geology. Model studies showed that this approach is especially useful in removing the terrain effects on complex 2D subsurface structures. The other purpose of this study is to emphasize the importance of a proper terrain correction for data from sites having mountainous topography over complex geology, e.g., strike-slip faults, suture zones and rift valleys. Some examples of MT data sets collected from the North Anatolian Fault Zone and from the thrust regions of the Western Taurides will be presented.« less

On the energy balance closure and net radiation in complex terrain

PubMed Central

Wohlfahrt, Georg; Hammerle, Albin; Niedrist, Georg; Scholz, Katharina; Tomelleri, Enrico; Zhao, Peng

2017-01-01

In complex, sloping terrain, horizontal measurements of net radiation are not reflective of the radiative energy available for the conductive and convective heat exchange of the underlying surface. Using data from a grassland site on a mountain slope characterised by spatial heterogeneity in inclination and aspect, we tested the hypothesis that a correction of the horizontal net radiation measurements which accounts for the individual footprint contributions of the various surfaces to the measured sensible and latent heat eddy covariance fluxes will yield more realistic slope-parallel net radiation estimates compared to a correction based on the average inclination and aspect of the footprint. Our main result is that both approaches led to clear, but very similar improvements in the phase between available energy and the sum of the latent and sensible heat fluxes. As a consequence the variance in the sum of latent and sensible heat flux explained by available radiation improved by >10 %, while energy balance closure improved only slightly. This is shown to be mainly due to the average inclination and aspect corresponding largely with the inclination and aspect of the main flux source area in combination with a limited sensitivity of the slope correction to small angular differences in, particularly, inclination and aspect. We conclude with a discussion of limitations of the present approach and future research directions. PMID:28066093

Image processing-based framework for continuous lane recognition in mountainous roads for driver assistance system

NASA Astrophysics Data System (ADS)

Manoharan, Kodeeswari; Daniel, Philemon

2017-11-01

This paper presents a robust lane detection technique for roads on hilly terrain. The target of this paper is to utilize image processing strategies to recognize lane lines on structured mountain roads with the help of improved Hough transform. Vision-based approach is used as it performs well in a wide assortment of circumstances by abstracting valuable information contrasted with other sensors. The proposed strategy processes the live video stream, which is a progression of pictures, and concentrates on the position of lane markings in the wake of sending the edges through different channels and legitimate thresholding. The algorithm is tuned for Indian mountainous curved and paved roads. A technique of computation is utilized to discard the disturbing lines other than the credible lane lines and show just the required prevailing lane lines. This technique will consequently discover two lane lines that are nearest to the vehicle in a picture as right on time as could reasonably be expected. Various video sequences on hilly terrain are tested to verify the effectiveness of our method, and it has shown good performance with a detection accuracy of 91.89%.

Geological remote sensing in Africa

NASA Technical Reports Server (NTRS)

Sabins, Floyd F., Jr.; Bailey, G. Bryan; Abrams, Michael J.

1987-01-01

Programs using remote sensing to obtain geologic information in Africa are reviewed. Studies include the use of Landsat MSS data to evaluate petroleum resources in sedimentary rock terrains in Kenya and Sudan and the use of Landsat TM 30-m resolution data to search for mineral deposits in an ophiolite complex in Oman. Digitally enhanced multispectral SPOT data at a scale of 1:62,000 were used to map folds, faults, diapirs, bedding attitudes, and stratigraphic units in the Atlas Mountains in northern Algeria. In another study, SIR-A data over a vegetated and faulted area of Sierra Leone were compared with data collected by the Landsat MSS and TM systems. It was found that the lineaments on the SIR-A data were more easily detected.

Complex terrain influences ecosystem carbon responses to temperature and precipitation

NASA Astrophysics Data System (ADS)

Reyes, W. M.; Epstein, H. E.; Li, X.; McGlynn, B. L.; Riveros-Iregui, D. A.; Emanuel, R. E.

2017-08-01

Terrestrial ecosystem responses to temperature and precipitation have major implications for the global carbon cycle. Case studies demonstrate that complex terrain, which accounts for more than 50% of Earth's land surface, can affect ecological processes associated with land-atmosphere carbon fluxes. However, no studies have addressed the role of complex terrain in mediating ecophysiological responses of land-atmosphere carbon fluxes to climate variables. We synthesized data from AmeriFlux towers and found that for sites in complex terrain, responses of ecosystem CO2 fluxes to temperature and precipitation are organized according to terrain slope and drainage area, variables associated with water and energy availability. Specifically, we found that for tower sites in complex terrain, mean topographic slope and drainage area surrounding the tower explained between 51% and 78% of site-to-site variation in the response of CO2 fluxes to temperature and precipitation depending on the time scale. We found no such organization among sites in flat terrain, even though their flux responses exhibited similar ranges. These results challenge prevailing conceptual framework in terrestrial ecosystem modeling that assumes that CO2 fluxes derive from vertical soil-plant-climate interactions. We conclude that the terrain in which ecosystems are situated can also have important influences on CO2 responses to temperature and precipitation. This work has implications for about 14% of the total land area of the conterminous U.S. This area is considered topographically complex and contributes to approximately 15% of gross ecosystem carbon production in the conterminous U.S.

Hydraulic risk assessment of bridges using UAV photogrammetry

NASA Astrophysics Data System (ADS)

Hackl, Jürgen; Adey, Bryan T.; Woźniak, Michał; Schümperlin, Oliver

2017-04-01

Road networks are essential for economic growth and development. Of the objects within a road network, bridges are of special interest, because their failure often results in relatively large interruptions to how the network is used, their replacement costs are generally large, and it usually takes a considerable amount of time to restore them once they have failed. Of the different types of bridges, bridges in mountainous regions are of special interest because their failure could cause severe societal consequences, for example, if it renders an area inaccessible. One of the main causes of the failure of bridges in mountainous regions is the occurrence of a hydraulic event, for example, flood waters above a certain level, scour below a certain depth or debris build up beyond a certain level. An assessment of risk related to a bridge in a mountainous region is challenging. The probability of occurrence of these events, and the resulting consequences, depend greatly on the characteristics (e.g. slope, soil, vegetation, precipitation, …) of the specific regions where the bridges are located. An indication of the effect of these characteristics can be seen in the sediment deposition during floods in mountain catchments. Additionally, there is often no, or no recent, topological information that can be used to develop terrain models to be used for realistic water flow simulations in mountain regions, and most hydrology and hydraulic models have been developed for lower gradient rivers and can often not be directly used to model water flow in mountain rivers. In an effort to improve the assessment of risk related to bridges in mountainous regions, using the setting for risk assessments established by Hackl et al. (2015) and Adey et al. (2016), an investigation was undertaken to determine whether unmanned aerial vehicles (UAVs) and photogrammetry could be used to generate the topological information required to run realistic water flow simulations. The process investigated includes: the use of geo-referenced images, taken by an UAV, the exportation of these images into a photogrammetric software, the creation of a 3D mesh of the terrain from these images, the conversion of the 3D mesh to a computational mesh, the use of the computational mesh to build a hydrodynamic model, and the use of the hydrodynamic model to run flow simulations. The process was used to estimate the complex water flow near a single span concrete bridge in the Canton of Grisons, Switzerland. The hydraulic events (abutment scour and overflow) predicted by the developed model were compared with with historical observations from a recent flood event in the region. The hydraulic events predicted by the developed model correspond with historical observations, indicating that the topological information collected in this way is sufficiently accurate to be used to simulate complex flow situations, which can be used in bridge risk assessments. Hackl, J., Adey, B.T., Heitzler, M., and Iosifescu Enescu, I. (2015). "An Overarching Risk Assessment Process to Evaluate the Risks Associated with Infrastructure Networks due to Natural Hazards." International Journal of Performability Engineering, 11(2), 153-168. Adey, B.T., Hackl, J., Lam, J.C., van Gelder, P., Prak, P., van Erp, N., Heitzler, M., Iosifescu Enescu, I., and Hurni, L. (2016). "Ensuring acceptable levels of infrastructure related risks due to natural hazards with emphasis on conducting stress tests." 1st International Symposium on Infrastructure Asset Management (SIAM2016), K. Kobayashi, ed., Kyoto, Japan, 19-29 (Jan).

Cattle site preference in northeastern Oregon

USDA-ARS?s Scientific Manuscript database

Free-roaming beef cattle naturally gravitate to locations on the landscape that provide them food, water, shelter, and security. In mountainous environments, animals are also sensitive to land physiography, generally preferring level terrain near established trails and travel routes. Our study was...

Vorticity and turbulence observations during a wildland fire on sloped terrain

NASA Astrophysics Data System (ADS)

Contezac, J.; Clements, C. B.; Hall, D.; Seto, D.; Davis, B.

2013-12-01

Fire-atmosphere interactions represent an atmospheric boundary-layer regime typically associated with complex circulations that interact with the fire front. In mountainous terrain, these interactions are compounded by terrain-driven circulations that often lead to extreme fire behavior. To better understand the role of complex terrain on fire behavior, a set of field experiments was conducted in June 2012 in the Coast Range of central California. The experiments were conducted on steep valley sidewalls to allow fires to spread upslope. Instrumentation used to measure fire-atmosphere interactions included three micrometeorological towers arranged along the slope and equipped with sonic anemometers, heat flux radiometers, and fine-wire thermocouples. In addition, a scanning Doppler lidar was used to measured winds within and above the valley, and airborne video imagery was collected to monitor fire behavior characteristics. The experimental site was located on the leeside of a ridge where terrain-induced flow and opposing mesoscale winds aloft interacted to create a zone of high wind shear. During the burn, the interaction between the fire and atmosphere caused the generation of several fire whirls that develop as a result of several environmental conditions including shear-generated vorticity and fire front geometry. Airborne video imagery indicated that upon ignition, the plume tilted in the opposite direction from the fire movement suggesting that higher horizontal momentum from aloft was brought to the surface, resulting in much slower fire spread rates due to opposing winds. However, after the fire front had passed the lowest tower located at the base of the slope, a shift in wind speed and direction caused a fire whirl to develop near an L-shaped kink in the fire front. Preliminary results indicate that at this time, winds at the bottom of the slope began to rotate with horizontal vorticity values of -0.2 s^-1. Increased heat flux values at this time indicated that winds were continuing to transport heat towards the slope. As the winds shifted with the fire whirl, heat flux values returned to ambient indicating the passage of the fire plume. A 0.15 hPa decrease in pressure was also observed at the first tower during this period. Further analyses to be presented include vorticity estimates from the Doppler lidar and turbulence kinetic energy measurements from the in situ towers.

2014 NASA Centennial Challenges Sample Return Robot Challenge

NASA Image and Video Library

2014-06-14

The NASA Centennial Challenges prize, level one, is presented to team Mountaineers for successfully completing level one of the NASA 2014 Sample Return Robot Challenge, from left, Ryan Watson, Team Mountaineers; Lucas Behrens, Team Mountaineers; Jarred Strader, Team Mountaineers; Yu Gu, Team Mountaineers; Scott Harper, Team Mountaineers; Dorothy Rasco, NASA Deputy Associate Administrator for the Space Technology Mission Directorate; Laurie Leshin, Worcester Polytechnic Institute (WPI) President; David Miller, NASA Chief Technologist; Alexander Hypes, Team Mountaineers; Nick Ohi,Team Mountaineers; Marvin Cheng, Team Mountaineers; Sam Ortega, NASA Program Manager for Centennial Challenges; and Tanmay Mandal, Team Mountaineers;, Saturday, June 14, 2014, at Worcester Polytechnic Institute (WPI) in Worcester, Mass. Team Mountaineers was the only team to complete the level one challenge. During the competition, teams were required to demonstrate autonomous robots that can locate and collect samples from a wide and varied terrain, operating without human control. The objective of this NASA-WPI Centennial Challenge was to encourage innovations in autonomous navigation and robotics technologies. Innovations stemming from the challenge may improve NASA's capability to explore a variety of destinations in space, as well as enhance the nation's robotic technology for use in industries and applications on Earth. Photo Credit: (NASA/Joel Kowsky)

2014 NASA Centennial Challenges Sample Return Robot Challenge

NASA Image and Video Library

2014-06-14

The NASA Centennial Challenges prize, level one, is presented to team Mountaineers for successfully completing level one of the NASA 2014 Sample Return Robot Challenge, from left, Ken Stafford, WPI Challenge technical advisor; Colleen Shaver, WPI Challenge Manager; Ryan Watson, Team Mountaineers; Marvin Cheng, Team Mountaineers; Alexander Hypes, Team Mountaineers; Jarred Strader, Team Mountaineers; Lucas Behrens, Team Mountaineers; Yu Gu, Team Mountaineers; Nick Ohi, Team Mountaineers; Dorothy Rasco, NASA Deputy Associate Administrator for the Space Technology Mission Directorate; Scott Harper, Team Mountaineers; Tanmay Mandal, Team Mountaineers; David Miller, NASA Chief Technologist; Sam Ortega, NASA Program Manager for Centennial Challenges, Saturday, June 14, 2014, at Worcester Polytechnic Institute (WPI) in Worcester, Mass. Team Mountaineers was the only team to complete the level one challenge. During the competition, teams were required to demonstrate autonomous robots that can locate and collect samples from a wide and varied terrain, operating without human control. The objective of this NASA-WPI Centennial Challenge was to encourage innovations in autonomous navigation and robotics technologies. Innovations stemming from the challenge may improve NASA's capability to explore a variety of destinations in space, as well as enhance the nation's robotic technology for use in industries and applications on Earth. Photo Credit: (NASA/Joel Kowsky)

Turbulence in breaking mountain waves and atmospheric rotors estimated from airborne in situ and Doppler radar measurements.

PubMed

Strauss, Lukas; Serafin, Stefano; Haimov, Samuel; Grubišić, Vanda

2015-10-01

Atmospheric turbulence generated in flow over mountainous terrain is studied using airborne in situ and cloud radar measurements over the Medicine Bow Mountains in southeast Wyoming, USA. During the NASA Orographic Clouds Experiment (NASA06) in 2006, two complex mountain flow cases were documented by the University of Wyoming King Air research aircraft carrying the Wyoming Cloud Radar. The structure of turbulence and its intensity across the mountain range are described using the variance of vertical velocity σw2 and the cube root of the energy dissipation rate ɛ 1/3 (EDR). For a quantitative analysis of turbulence from the cloud radar, the uncertainties in the Doppler wind retrieval have to be taken into account, such as the variance of hydrometeor fall speed and the contamination of vertical Doppler velocity by the horizontal wind. A thorough analysis of the uncertainties shows that 25% accuracy or better can be achieved in regions of moderate to severe turbulence in the lee of the mountains, while only qualitative estimates of turbulence intensity can be obtained outside the most turbulent regions. Two NASA06 events exhibiting large-amplitude mountain waves, mid-tropospheric wave breaking, and rotor circulations are examined. Moderate turbulence is found in a wave-breaking region with σw2 and EDR reaching 4.8 m 2 s -2 and 0.25 m 2/3 s -1 , respectively. Severe turbulence is measured within the rotor circulations with σw2 and EDR respectively in the ranges of 7.8-16.4 m 2 s -2 and 0.50-0.77 m 2/3 s -1 . A unique result of this study is the quantitative estimation of the intensity of turbulence and its spatial distribution in the interior of atmospheric rotors, provided by the radar-derived turbulence fields.

Secondary Generation of Mountain Waves in the Stratosphere

NASA Astrophysics Data System (ADS)

Woods, Bryan K.

Secondary generation of mountain waves was documented using in situ aircraft data from the Terrain-Induced Rotor Experiment (T-REX). Mountain waves propagating from the Sierra Nevada generated secondary waves due to stratospheric wave breaking. The seminal Eliassen and Palm (1961) relation of mountain wave energy and momentum fluxes is observationally verified for the first time. One case of reversed wave fluxes in the stratosphere is shown to be the result of multiscale secondary waves propagating down from the stratosphere. The Tropopause Inversion Layer (TIL) is shown to be capable of serving as a wave duct trapping such secondary waves. Simple idealized 2D simulations are shown to reproduce secondary wave patterns that bare striking resemblance to those observed in T-REX. However, 3D simulations are shown to fail to reproduce realistic secondary waves.

Medical Problems in High Mountain Environments. A Handbook for Medical Officers

DTIC Science & Technology

1994-02-01

include abdominal pain, nausea, abdominal distension , intestinal gas and frequent diarrhea. Acutely, symptoms may also include weakness, loss of...altitude terrain. As might be expected, the greatest effects are on aerobic activity while anaerobic exercise and muscular strength are virtually

Experimental project : use of shredded tires for lightweight fill.

DOT National Transportation Integrated Search

1991-02-01

Shredded rubber tires have been used as lightweight fill in repair of a landslide that occurred under a highway embankment in mountainous terrain on Highway US 42 (Oregon State route #35). The force driving the slide was decreased by removing the soi...

An Improved Method for Deriving Mountain Glacier Motion by Integrating Information of Intensity and Phase Based on SAR Images

NASA Astrophysics Data System (ADS)

Ruan, Z.; Yan, S.; Liu, G.; Guo, H.; LV, M.

2016-12-01

Glacier dynamic parameters, such as velocity fields and motion patterns, play a crucial role in the estimation of ice mass balance variations and in the monitoring of glacier-related hazards. Characterized by being independent of cloud cover and solar illumination, synthetic aperture radar (SAR) at long wavelength has provided an invaluable way to measure mountain glacier motion. Compared with optical imagery and in-situ surveys, it has been successfully exploited to detect glacier motion in many previous studies, usually with pixel-tracking (PT), differential interferometric SAR (D-InSAR) and multi-aperture interferometry (MAI) methods. However, the reliability of the extracted glacier velocities heavily depends on complex terrain topography and diverse glacial motion types. D-InSAR and MAI techniques are prone to fail in the case of mountain glaciers because of the steep terrain and their narrow sizes. PT method is considered to be the alternative way, although it is subject to a low accuracy.We propose an integrated strategy based on comprehensive utilization of the phase information (D-InSAR and MAI) and intensity information (PT) of SAR images, which is used to yield an accurate and detailed ice motion pattern for the typical glaciers in the West Kunlun Mountains, China, by fully exploiting the SAR imagery. In order to avoid the error introduced by the motion decomposition operation, the derived ice motion is presented in the SAR imaging dimension composed of the along-track and slant-range directions. The Shuttle Radar Topographic Mission (SRTM) digital elevation model (DEM) at 3 arc-sec resolution is employed to remove and compensate for the topography-related signal in the D-InSAR, MAI, and PT methods. Compared with the traditional SAR-based methods, the proposed approach can determine the ice motion over a widely varying range of ice velocities with a relatively high accuracy. Its capability is proved by the detailed ice displacement pattern with the average accuracy of 0.2 m covering the entire glacier surface, which shows a maximum ice movement of 4.9 m over 46 days. Therefore, the integrated approach could present us with a novel way to comprehensively and accurately understand glacier dynamics by overcoming the incoherence phenomenon, and has great potential for glaciology study.

Airsheds, Isotopes and Ecosystem Metabolism in Mountainous Terrain

NASA Astrophysics Data System (ADS)

Sulzman, E.; Barnard, H.; Bond, B. J.; Czarnomski, N. M.; Hauck, M.; Kayler, Z.; Mix, A. C.; Pypker, T.; Rugh, W.; Unsworth, M.

2005-12-01

At least 20% of the terrestrial surface of the earth is covered by mountains, which contain many of the world's most productive ecosystems. Interactions between vegetation and the physical environment are often very different in mountains than on flat land. However, few studies have addressed these unique interactions, and many of the tools used to measure and monitor ecosystem metabolism are difficult or impossible to use in complex, mountainous terrain. In a project we call the "Andrews Airshed study" located in western Oregon Cascades, we aim to identify and explore sources of variation in the isotopic composition of ecosystem respiration (δ13CR-eco) and airflow patterns in cold-air drainage, with the eventual aim of "inverting" this understanding so that we can use δ13CR-eco to monitor intra- and inter-annual variations in ecosystem metabolism on a basin scale. We are measuring patterns of airflow, quantifying the CO2 concentration in the flow, and measuring the carbon isotope composition of ecosystem-respired CO2 as well as soil-respired CO2 (δ13CR-soil), which accounts for more than half of δ13CR-eco. We have designed an automated air sampling device that we programmed to sample air at 10 ppm intervals from 30 m above the stream in our 100 ha, deeply-incised watershed. Samples are collected via Valco valves into stainless steel tubing that can be connected directly to an isotope ratio mass spectrometer. We also designed and installed soil gas sampling probes, which are located in five 10 m2 sampling plots from ridge top to valley floor to the opposite ridge top. Weekly samples (May-Sept, 2005) of air from soil and the nocturnal air flow show seasonal variation in δ13CR-eco over a 2 per mil range, with more enriched values corresponding to lower soil moisture. Soil-respired CO2 also reveal seasonality and are isotopically enriched compared with above-ground air. δ13CR-soil values from north- and south-facing slopes of the watershed differ by 1 per mil, with south-facing values consistently enriched relative to those of the north-facing slope. We are concurrently conducting studies to determine the appropriate footprint of respired CO2 in the nocturnal airstream, which will allow us to overlay the data properly.

A Mountain Range within Pluto Heart

NASA Image and Video Library

2015-07-21

A newly discovered mountain range lies near the southwestern margin of Pluto heart-shaped Tombaugh Regio Tombaugh Region, situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by NASA's New Horizons' Long Range Reconnaissance Imager (LORRI) on July 14, 2015, from a distance of 48,000 miles (77,000 kilometers) and sent back to Earth on July 20. Features as small as a half-mile (1 kilometer) across are visible. These frozen peaks are estimated to be one-half mile to one mile (1-1.5 kilometers) high, about the same height as the United States' Appalachian Mountains. The Norgay Montes (Norgay Mountains) discovered by New Horizons on July 15 more closely approximate the height of the taller Rocky Mountains The names of features on Pluto have all been given on an informal basis by the New Horizons team. http://photojournal.jpl.nasa.gov/catalog/PIA19842

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, John C.; Mallia, Derek V.; Wu, Dien

Despite the need for researchers to understand terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO 2 concentrations, knowledge of these fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where complex meteorology and lack of observations lead to large uncertainties in carbon fluxes. Yet mountainous regions are often where significant forest cover and biomass are found – i.e., areas that have the potential to serve as carbon sinks. As CO 2 observations are carried out in mountainous areas, it is imperative that they are properly interpreted to yield informationmore » about carbon fluxes. In this paper, we present CO 2 observations at three sites in the mountains of the western US, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes from the CO 2 observations, with emphasis on the observed and simulated diurnal cycles of CO 2. We show that atmospheric models can systematically simulate the wrong diurnal cycle and significantly misinterpret the CO 2 observations, due to erroneous atmospheric flows as a result of terrain that is misrepresented in the model. This problem depends on the selected vertical level in the model and is exacerbated as the spatial resolution is degraded, and our results indicate that a fine grid spacing of ~4 km or less may be needed to simulate a realistic diurnal cycle of CO 2 for sites on top of the steep mountains examined here in the American Rockies. In conclusion, in the absence of higher resolution models, we recommend coarse-scale models to focus on assimilating afternoon CO 2 observations on mountaintop sites over the continent to avoid misrepresentations of nocturnal transport and influence.« less

How can mountaintop CO 2 observations be used to constrain regional carbon fluxes?

DOE PAGES

Lin, John C.; Mallia, Derek V.; Wu, Dien; ...

2017-05-03

Despite the need for researchers to understand terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO 2 concentrations, knowledge of these fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where complex meteorology and lack of observations lead to large uncertainties in carbon fluxes. Yet mountainous regions are often where significant forest cover and biomass are found – i.e., areas that have the potential to serve as carbon sinks. As CO 2 observations are carried out in mountainous areas, it is imperative that they are properly interpreted to yield informationmore » about carbon fluxes. In this paper, we present CO 2 observations at three sites in the mountains of the western US, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes from the CO 2 observations, with emphasis on the observed and simulated diurnal cycles of CO 2. We show that atmospheric models can systematically simulate the wrong diurnal cycle and significantly misinterpret the CO 2 observations, due to erroneous atmospheric flows as a result of terrain that is misrepresented in the model. This problem depends on the selected vertical level in the model and is exacerbated as the spatial resolution is degraded, and our results indicate that a fine grid spacing of ~4 km or less may be needed to simulate a realistic diurnal cycle of CO 2 for sites on top of the steep mountains examined here in the American Rockies. In conclusion, in the absence of higher resolution models, we recommend coarse-scale models to focus on assimilating afternoon CO 2 observations on mountaintop sites over the continent to avoid misrepresentations of nocturnal transport and influence.« less

Idealised large-eddy-simulation of thermally driven flows over an isolated mountain range with multiple ridges

NASA Astrophysics Data System (ADS)

Lang, Moritz N.; Gohm, Alexander; Wagner, Johannes S.; Leukauf, Daniel; Posch, Christian

2014-05-01

Two dimensional idealised large-eddy-simulations are performed using the WRF model to investigate thermally driven flows during the daytime over complex terrain. Both the upslope flows and the temporal evolution of the boundary layer structure are studied with a constant surface heat flux forcing of 150 W m-2. In order to distinguish between different heating processes the flow is Reynold decomposed into its mean and turbulent part. The heating processes associated with the mean flow are a cooling through cold-air advection along the slopes and subsidence warming within the valleys. The turbulent component causes bottom-up heating near the ground leading to a convective boundary layer (CBL) inside the valleys. Overshooting potentially colder thermals cool the stably stratified valley atmosphere above the CBL. Compared to recent investigations (Schmidli 2013, J. Atmos. Sci., Vol. 70, No. 12: pp. 4041-4066; Wagner et al. 2014, manuscript submitted to Mon. Wea. Rev.), which used an idealised topography with two parallel mountain crests separated by a straight valley, this project focuses on multiple, periodic ridges and valleys within an isolated mountain range. The impact of different numbers of ridges on the flow structure is compared with the sinusoidal envelope-topography. The present simulations show an interaction between the smaller-scale upslope winds within the different valleys and the large-scale flow of the superimposed mountain-plain wind circulation. Despite a smaller boundary layer air volume in the envelope case compared to the multiple ridges case the volume averaged heating rates are comparable. The reason is a stronger advection-induced cooling along the slopes and a weaker warming through subsidence at the envelope-topography compared to the mountain range with multiple ridges.

How can mountaintop CO2 observations be used to constrain regional carbon fluxes?

NASA Astrophysics Data System (ADS)

Lin, John C.; Mallia, Derek V.; Wu, Dien; Stephens, Britton B.

2017-05-01

Despite the need for researchers to understand terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO2 concentrations, knowledge of these fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where complex meteorology and lack of observations lead to large uncertainties in carbon fluxes. Yet mountainous regions are often where significant forest cover and biomass are found - i.e., areas that have the potential to serve as carbon sinks. As CO2 observations are carried out in mountainous areas, it is imperative that they are properly interpreted to yield information about carbon fluxes. In this paper, we present CO2 observations at three sites in the mountains of the western US, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes from the CO2 observations, with emphasis on the observed and simulated diurnal cycles of CO2. We show that atmospheric models can systematically simulate the wrong diurnal cycle and significantly misinterpret the CO2 observations, due to erroneous atmospheric flows as a result of terrain that is misrepresented in the model. This problem depends on the selected vertical level in the model and is exacerbated as the spatial resolution is degraded, and our results indicate that a fine grid spacing of ˜ 4 km or less may be needed to simulate a realistic diurnal cycle of CO2 for sites on top of the steep mountains examined here in the American Rockies. In the absence of higher resolution models, we recommend coarse-scale models to focus on assimilating afternoon CO2 observations on mountaintop sites over the continent to avoid misrepresentations of nocturnal transport and influence.

Exploring a Variable-Resolution Approach for Simulating Regional Climate in the Rocky Mountain Region Using the VR-CESM

NASA Astrophysics Data System (ADS)

Wu, Chenglai; Liu, Xiaohong; Lin, Zhaohui; Rhoades, Alan M.; Ullrich, Paul A.; Zarzycki, Colin M.; Lu, Zheng; Rahimi-Esfarjani, Stefan R.

2017-10-01

The reliability of climate simulations and projections, particularly in the regions with complex terrains, is greatly limited by the model resolution. In this study we evaluate the variable-resolution Community Earth System Model (VR-CESM) with a high-resolution (0.125°) refinement over the Rocky Mountain region. The VR-CESM results are compared with observations, as well as CESM simulation at a quasi-uniform 1° resolution (UNIF) and Canadian Regional Climate Model version 5 (CRCM5) simulation at a 0.11° resolution. We find that VR-CESM is effective at capturing the observed spatial patterns of temperature, precipitation, and snowpack in the Rocky Mountains with the performance comparable to CRCM5, while UNIF is unable to do so. VR-CESM and CRCM5 simulate better the seasonal variations of precipitation than UNIF, although VR-CESM still overestimates winter precipitation whereas CRCM5 and UNIF underestimate it. All simulations distribute more winter precipitation along the windward (west) flanks of mountain ridges with the greatest overestimation in VR-CESM. VR-CESM simulates much greater snow water equivalent peaks than CRCM5 and UNIF, although the peaks are still 10-40% less than observations. Moreover, the frequency of heavy precipitation events (daily precipitation ≥ 25 mm) in VR-CESM and CRCM5 is comparable to observations, whereas the same events in UNIF are an order of magnitude less frequent. In addition, VR-CESM captures the observed occurrence frequency and seasonal variation of rain-on-snow days and performs better than UNIF and CRCM5. These results demonstrate the VR-CESM's capability in regional climate modeling over the mountainous regions and its promising applications for climate change studies.

The polycyclic Lausche Volcano (Lausitz Volcanic Field) and its message concerning landscape evolution in the Lausitz Mountains (northern Bohemian Massif, Central Europe)

NASA Astrophysics Data System (ADS)

Wenger, Erik; Büchner, Jörg; Tietz, Olaf; Mrlina, Jan

2017-09-01

The Tertiary Lausitz Volcanic Field covers a broad area encompassing parts of Eastern Saxony (Germany), Lower Silesia (Poland) and North Bohemia (Czech Republic). Volcanism was predominantly controlled by the volcano-tectonic evolution of the Ohře Rift and culminated in the Lower Oligocene. This paper deals with the highest volcano of this area, the Lausche Hill (792.6 m a.s.l.) situated in the Lausitz Mountains. We offer a reconstruction of the volcanic edifice and its eruptive history. Its complex genesis is reflected by six different eruption styles and an associated petrographic variety. Furthermore, the Lausche Volcano provides valuable information concerning the morphological evolution of its broader environs. The remnant of an alluvial fan marking a Middle Paleocene-Lower Eocene (62-50 Ma) palaeo-surface is preserved at the base of the volcano. The deposition of this fan can be attributed to a period of erosion of its nearby source area, the Lausitz Block that has undergone intermittent uplift at the Lausitz Overthrust since the Upper Cretaceous. The Lausche Hill is one of at least six volcanoes in the Lausitz Mountains which show an eminent low level of erosion despite their Oligocene age and position on elevated terrain. These volcanoes are exposed in their superficial level which clearly contradicts their former interpretation as subvolcanoes. Among further indications, this implies that the final morphotectonic uplift of the Lausitz Mountains started in the upper Lower Pleistocene ( 1.3 Ma) due to revived subsidence of the nearby Zittau Basin. It is likely that this neotectonic activity culminated between the Elsterian and Saalian Glaciation ( 320 ka). The formation of the low mountain range was substantially controlled by the intersection of the Lausitz Overthrust and the Ohře Rift.

Geographic location, network patterns and population distribution of rural settlements in Greece

NASA Astrophysics Data System (ADS)

Asimakopoulos, Avraam; Mogios, Emmanuel; Xenikos, Dimitrios G.

2016-10-01

Our work addresses the problem of how social networks are embedded in space, by studying the spread of human population over complex geomorphological terrain. We focus on villages or small cities up to a few thousand inhabitants located in mountainous areas in Greece. This terrain presents a familiar tree-like structure of valleys and land plateaus. Cities are found more often at lower altitudes and exhibit preference on south orientation. Furthermore, the population generally avoids flat land plateaus and river beds, preferring locations slightly uphill, away from the plateau edge. Despite the location diversity regarding geomorphological parameters, we find certain quantitative norms when we examine location and population distributions relative to the (man-made) transportation network. In particular, settlements at radial distance ℓ away from road network junctions have the same mean altitude, practically independent of ℓ ranging from a few meters to 10 km. Similarly, the distribution of the settlement population at any given ℓ is the same for all ℓ. Finally, the cumulative distribution of the number of rural cities n(ℓ) is fitted to the Weibull distribution, suggesting that human decisions for creating settlements could be paralleled to mechanisms typically attributed to this particular statistical distribution.

Monitoring Citrus Soil Moisture and Nutrients Using an IoT Based System.

PubMed

Zhang, Xueyan; Zhang, Jianwu; Li, Lin; Zhang, Yuzhu; Yang, Guocai

2017-02-23

Chongqing mountain citrus orchard is one of the main origins of Chinese citrus. Its planting terrain is complex and soil parent material is diverse. Currently, the citrus fertilization, irrigation and other management processes still have great blindness. They usually use the same pattern and the same formula rather than considering the orchard terrain features, soil differences, species characteristics and the state of tree growth. With the help of the ZigBee technology, artificial intelligence and decision support technology, this paper has developed the research on the application technology of agricultural Internet of Things for real-time monitoring of citrus soil moisture and nutrients as well as the research on the integration of fertilization and irrigation decision support system. Some achievements were obtained including single-point multi-layer citrus soil temperature and humidity detection wireless sensor nodes and citrus precision fertilization and irrigation management decision support system. They were applied in citrus base in the Three Gorges Reservoir Area. The results showed that the system could help the grower to scientifically fertilize or irrigate, improve the precision operation level of citrus production, reduce the labor cost and reduce the pollution caused by chemical fertilizer.

Meso-beta scale numerical simulation studies of terrain-induced jet streak mass/momentum perturbations

NASA Technical Reports Server (NTRS)

Lin, Yuh-Lang; Kaplan, Michael L.

1995-01-01

Mesoscale model simulations provide insight into the complex jet streak adjustments on 11-12 July 1981 that preceded the first of two significant gravity wave events to have been generated over the Rocky Mountains in Montana. Simulations employing a variety of terrain treatments indicate that prior to wave formation, geostrophic adjustment processes modified the structure of the mid-upper tropospheric jet streak by creating secondary jetlets to the southeast of the polar jet streak in proximity to the gravity wave generation region. This simulated restructuring of the mid-upper tropospheric jet streak is the result of a four stage process. During stage 1, the wind adjusts to the mass field as the jet streak exit region propagates into the inflection point between the upstream trough and downstream ridge in the height field. Stage 2 is initiated as the mass field is forced to adjust to the new ageostrophic wind field created during stage 1. Stage 3 is defined by a second geostrophic adjustment process occurring in a similar manner but to the south and east of the adjustment which occurs during stage 1. A low-level mesoscale jetlet is formed during stage 4 in response to the low-level pressure falls that are established during stage 3. The perturbation of this jetlet, caused by orographically-induced adiabatic and diabatic physical processes, is the likely mechanism responsible for the generation of the first and second episode of observed gravity waves. The dynamics responsible for this wave episode are discussed as differential surface sensible heating inducing an orographically-forced mountain-plains solenoid, resulting in the formation of additional mesoscale jetlets and internal gravity waves. Also discussed is how convective latent heating modifies the numerically simulated terrain-induced internal gravity waves, especially their amplitude and phase velocities, which provide better agreement with those wave characteristics observed in nature. Finally, the three-dimensional linear response of a zonally uniform barotropic flow in a vertically unbounded, continuously stratified, Boussinesq atmosphere which is perturbed from geostrophic equilibrium is investigated.

Evaluation of different digital elevation models for analyzing drainage morphometric parameters in a mountainous terrain: a case study of the Supin-Upper Tons Basin, Indian Himalayas.

PubMed

Das, Sayantan; Patel, Priyank Pravin; Sengupta, Somasis

2016-01-01

With myriad geospatial datasets now available for terrain information extraction and particularly streamline demarcation, there arises questions regarding the scale, accuracy and sensitivity of the initial dataset from which these aspects are derived, as they influence all other parameters computed subsequently. In this study, digital elevation models (DEM) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER V2), Shuttle Radar Topography Mission (SRTM V4, C-Band, 3 arc-second), Cartosat -1 (CartoDEM 1.0) and topographical maps (R.F. 1:250,000 and 1:50,000), have been used to individually extract and analyze the relief, surface, size, shape and texture properties of a mountainous drainage basin. Nestled inside a mountainous setting, the basin is a semi-elongated one with high relief ratio (>90), steep slopes (25°-30°) and high drainage density (>3.5 km/sq km), as computed from the different DEMs. The basin terrain and stream network is extracted from each DEM, whose morphometric attributes are compared with the surveyed stream networks present in the topographical maps, with resampling of finer DEM datasets to coarser resolutions, to reduce scale-implications during the delineation process. Ground truth verifications for altitudinal accuracy have also been done by a GPS survey. DEMs derived from the 1:50,000 topographical map and ASTER GDEM V2 data are found to be more accurate and consistent in terms of absolute accuracy, than the other generated or available DEM data products, on basis of the morphometric parameters extracted from each. They also exhibit a certain degree of proximity to the surveyed topographical map.

Transference of 3D accelerations during cross country mountain biking.

PubMed

Macdermid, Paul W; Fink, Philip W; Stannard, Stephen R

2014-06-03

Investigations into the work demands of Olympic format cross country mountain biking suggest an incongruent relationship between work done and physiological strain experienced by participants. A likely but unsubstantiated cause is the extra work demand of muscle damping of terrain/surface induced vibrations. The purpose of this study was to describe the relationship between vibration mechanics and their interaction with terrain, bicycle and rider during a race pace effort on a cross country mountain bike track, on both 26″ and 29″ wheels. Participants completed one lap of a cross country track using 26″ and 29″ wheels, at race pace. Power, cadence, speed, heart rate and geographical position were sampled and logged every second for control purposes. Tri-axial accelerometers located on the bicycle and rider, recorded accelerations (128Hz) and were used to quantify vibrations experienced during the whole lap and over terrain sections (uphill and downhill). While there were no differences in power output (p=0.3062) and heart rate (p=0.8423), time to complete the lap was significantly (p=0.0061) faster on the 29″ wheels despite increased vibrations in the larger wheels (p=0.0020). Overall accelerometer data (RMS) showed location differences (p<0.0001), specifically between the point of interface of bike-body compared to those experienced at the lower back and head. The reduction in accelerations at both the lower back and head are imperative for injury prevention and demonstrates an additional non-propulsive, muscular, challenge to riding. Stress was greatest during downhill sections as acceleration differences between locations were greater when compared to uphill sections, and thus possibly prevent the recovery processes that may occur during non-propulsive load. Copyright © 2014 Elsevier Ltd. All rights reserved.

Investigation of the 3-D actinic flux field in mountainous terrain

PubMed Central

Wagner, J.E.; Angelini, F.; Blumthaler, M.; Fitzka, M.; Gobbi, G.P.; Kift, R.; Kreuter, A.; Rieder, H.E.; Simic, S.; Webb, A.; Weihs, P.

2011-01-01

During three field campaigns spectral actinic flux was measured from 290–500 nm under clear sky conditions in Alpine terrain and the associated O3- and NO2-photolysis frequencies were calculated and the measurement products were then compared with 1-D- and 3-D-model calculations. To do this 3-D-radiative transfer model was adapted for actinic flux calculations in mountainous terrain and the maps of the actinic flux field at the surface, calculated with the 3-D-radiative transfer model, are given. The differences between the 3-D- and 1-D-model results for selected days during the campaigns are shown, together with the ratios of the modeled actinic flux values to the measurements. In many cases the 1-D-model overestimates actinic flux by more than the measurement uncertainty of 10%. The results of using a 3-D-model generally show significantly lower values, and can underestimate the actinic flux by up to 30%. This case study attempts to quantify the impact of snow cover in combination with topography on spectral actinic flux. The impact of snow cover on the actinic flux was ~ 25% in narrow snow covered valleys, but for snow free areas there were no significant changes due snow cover in the surrounding area and it is found that the effect snow-cover at distances over 5 km from the point of interest was below 5%. Overall the 3-D-model can calculate actinic flux to the same accuracy as the 1-D-model for single points, but gives a much more realistic view of the surface actinic flux field in mountains as topography and obstruction of the horizon are taken into account. PMID:26412915

Environmental drivers of spatial patterns of topsoil nitrogen and phosphorus under monsoon conditions in a complex terrain of South Korea

PubMed Central

Choi, Kwanghun; Spohn, Marie; Park, Soo Jin; Huwe, Bernd; Ließ, Mareike

2017-01-01

Nitrogen (N) and phosphorus (P) in topsoils are critical for plant nutrition. Relatively little is known about the spatial patterns of N and P in the organic layer of mountainous landscapes. Therefore, the spatial distributions of N and P in both the organic layer and the A horizon were analyzed using a light detection and ranging (LiDAR) digital elevation model and vegetation metrics. The objective of the study was to analyze the effect of vegetation and topography on the spatial patterns of N and P in a small watershed covered by forest in South Korea. Soil samples were collected using the conditioned latin hypercube method. LiDAR vegetation metrics, the normalized difference vegetation index (NDVI), and terrain parameters were derived as predictors. Spatial explicit predictions of N/P ratios were obtained using a random forest with uncertainty analysis. We tested different strategies of model validation (repeated 2-fold to 20-fold and leave-one-out cross validation). Repeated 10-fold cross validation was selected for model validation due to the comparatively high accuracy and low variance of prediction. Surface curvature was the best predictor of P contents in the organic layer and in the A horizon, while LiDAR vegetation metrics and NDVI were important predictors of N in the organic layer. N/P ratios increased with surface curvature and were higher on the convex upper slope than on the concave lower slope. This was due to P enrichment of the soil on the lower slope and a more even spatial distribution of N. Our digital soil maps showed that the topsoils on the upper slopes contained relatively little P. These findings are critical for understanding N and P dynamics in mountainous ecosystems. PMID:28837590

Simulating Canopy-Level Solar Induced Fluorescence with CLM-SIF 4.5 at a Sub-Alpine Conifer Forest in the Colorado Rockies

NASA Astrophysics Data System (ADS)

Raczka, B. M.; Bowling, D. R.; Lin, J. C.; Lee, J. E.; Yang, X.; Duarte, H.; Zuromski, L.

2017-12-01

Forests of the Western United States are prone to drought, temperature extremes, forest fires and insect infestation. These disturbance render carbon stocks and land-atmosphere carbon exchanges highly variable and vulnerable to change. Regional estimates of carbon exchange from terrestrial ecosystem models are challenged, in part, by a lack of net ecosystem exchange observations (e.g. flux towers) due to the complex mountainous terrain. Alternatively, carbon estimates based on light use efficiency models that depend upon remotely-sensed greenness indices are challenged due to a weak relationship with GPP during the winter season. Recent advances in the retrieval of remotely sensed solar induced fluorescence (SIF) have demonstrated a strong seasonal relationship between GPP and SIF for deciduous, grass and, to a lesser extent, conifer species. This provides an important opportunity to use remotely-sensed SIF to calibrate terrestrial ecosystem models providing a more accurate regional representation of biomass and carbon exchange across mountainous terrain. Here we incorporate both leaf-level fluorescence and leaf-to-canopy radiative transfer represented by the SCOPE model into CLM 4.5 (CLM-SIF). We simulate canopy level fluorescence at a sub-alpine forest site (Niwot Ridge, Colorado) and test whether these simulations reproduce remotely-sensed SIF from a satellite (GOME2). We found that the average peak SIF during the growing season (yrs 2007-2013) was similar between the model and satellite observations (within 15%); however, simulated SIF during the winter season was significantly greater than the satellite observations (5x higher). This implies that the fluorescence yield is overestimated by the model during the winter season. It is important that the modeled representation of seasonal fluorescence yield is improved to provide an accurate seasonal representation of SIF across the Western United States.

The Importance of Capturing Topographic Features for Modeling Groundwater Flow and Transport in Mountainous Watersheds

NASA Astrophysics Data System (ADS)

Wang, C.; Gomez-Velez, J. D.; Wilson, J. L.

2017-12-01

Groundwater plays a key role in runoff generation and stream water chemistry from reach to watershed scales. The spatial distribution of ridges and streams can influence the spatial patterns of groundwater recharge and drainage, specially in mountainous terrains where these features are more prominent. However, typical modeling efforts simplify or ignore some of these features due to computational limitations without a systematic investigation of the implications for flow and transport within the watershed. In this study, we investigate the effect of capturing key topographic features on modeled groundwater flow and transport characteristics in a mountainous watershed. We build model scenarios of different topographic complexity levels (TCLs) to capture different levels of representation of streams and ridges in the model. Modeled baseflow and groundwater mean residence time (MRT) are used to quantify the differences among TCLs. Our results show that capturing the streams and ridges has a significant influence on simulated groundwater flow and transport patterns. Topographic complexity controls the proportion of baseflow generated from local, intermediate, and regional flow paths, thus influencing the amount and MRT of basefow flowing into streams of different Horton-Strahler orders. We further simulate the concentration of solute exported into streams from subsurface chemical weathering. The concentration of chemical weathering products in streams is less sensitive to model TCL due to the thermodynamic constraint on the equilibrium concentration of the chemical weathering. We also tested the influence of geology on the effect of TCL. The effect of TCL is consistent under different geological conditions; however, it is enhanced in models with low hydraulic conductivity because more of the flow is forced into shallow and local flow paths. All of these changes can affect our ability to interpret environmental tracer data and predict bio- and geo-chemical evolution of stream water in mountainous watersheds.

High Resolution Simulations of Pollution Vertical Stratification over Santiago and its Transport to the Chilean Andes

NASA Astrophysics Data System (ADS)

Orfanoz-Cheuquelaf, A. P.; Gallardo, L.; Huneeus, N.; Lambert, F.

2015-12-01

Santiago, Chile (33.5 S, 70.5 W, 500 m.a.s.l., population 7 millions) is a large city situated in a basin surrounded by the Andes in the East and smaller mountain ranges to the North, West, and South. It is plagued by abnormally high pollution levels for its size due to climatological and topological features. To date, it is unclear how far the urban pollution plume reaches up the mountain. Here we explore the region's complex atmospheric circulation and particularly the transport of black carbon (BC) using a state of the art numerical model (WRF-Chem, Weather Research and Forecasting model).Observations indicate the presence of multiple layers within the boundary layer, as well as the occurrence of uncoupled layers above the boundary layer. Here we explore mechanisms within our simulation that may explain these features. Our results suggest that they may correspond to residual layers that are produced by recirculation along mountain slopes due to the complex terrain around the city.In late August 2013, a short multi-platform measuring campaign (DIVERSOL) took place in the Santiago basin, providing the first vertical profiles of BC, accompanied by meteorological soundings. We analyze the dispersion of a quasi-passive tracer (carbon monoxide) of black carbon in our simulation to improve our understanding of the governing mixing and transport processes. We also perform sensitivity studies with respect to vertical resolution and turbulence schemes, contrasting our results against DIVERSOL data. Our simulations suggest that pollutants emitted in Santiago could reach the high regions of Andes mountains during the afternoon circulation, thus affecting local glaciers. With an entire year of simulation we find that the stratification of pollutants within the basin displays a seasonal signal, as well as a capacity to reach the Chilean Andes and affect the Andean cryosphere.

Topographic changes and their driving factors after 2008 Wenchuan Earthquake

NASA Astrophysics Data System (ADS)

Li, C.; Wang, M.; Xie, J.; Liu, K.

2017-12-01

The Wenchuan Ms 8.0 Earthquake caused topographic change in the stricken areas because of the formation of numerous coseismic landslides. The emergence of new landslides and debris flows and movement of loose materials under the driving force of heavy rainfall could further shape the local topography. Dynamic topographic changes in mountainous areas stricken by major earthquakes have a strong linkage to the development and occurrence of secondary disasters. However, little attention has been paid to continuously monitoring mountain environment change after such earthquakes. A digital elevation model (DEM) is the main feature of the terrain surface, in our research, we extracted DEM in 2013 and 2015 of a typical mountainous area severely impacted by the 2008 Wenchuan earthquake from the ZY-3 stereo pair images with validation by field measurement. Combined with the elevation dataset in 2002 and 2010, we quantitatively assessed elevation changes in different years and qualitatively analyzed spatiotemporal variation of the terrain and mass movement across the study area. The results show that the earthquake stricken area experienced substantial elevation changes caused by seismic forces and subsequent rainfalls. Meanwhile, deposits after the earthquake are mainly accumulated on the river-channels and mountain ridges and deep gullies which increase the risk of other geo-hazards. And the heavy rainfalls after the earthquake have become the biggest driver of elevation reduction, which overwhelmed elevation increase during the major earthquake. Our study provided a better understanding of subsequent hazards and risks faced by residents and communities stricken by major earthquakes.

Multitemporal Snow Cover Mapping in Mountainous Terrain for Landsat Climate Data Record Development

NASA Technical Reports Server (NTRS)

Crawford, Christopher J.; Manson, Steven M.; Bauer, Marvin E.; Hall, Dorothy K.

2013-01-01

A multitemporal method to map snow cover in mountainous terrain is proposed to guide Landsat climate data record (CDR) development. The Landsat image archive including MSS, TM, and ETM+ imagery was used to construct a prototype Landsat snow cover CDR for the interior northwestern United States. Landsat snow cover CDRs are designed to capture snow-covered area (SCA) variability at discrete bi-monthly intervals that correspond to ground-based snow telemetry (SNOTEL) snow-water-equivalent (SWE) measurements. The June 1 bi-monthly interval was selected for initial CDR development, and was based on peak snowmelt timing for this mountainous region. Fifty-four Landsat images from 1975 to 2011 were preprocessed that included image registration, top-of-the-atmosphere (TOA) reflectance conversion, cloud and shadow masking, and topographic normalization. Snow covered pixels were retrieved using the normalized difference snow index (NDSI) and unsupervised classification, and pixels having greater (less) than 50% snow cover were classified presence (absence). A normalized SCA equation was derived to independently estimate SCA given missing image coverage and cloud-shadow contamination. Relative frequency maps of missing pixels were assembled to assess whether systematic biases were embedded within this Landsat CDR. Our results suggest that it is possible to confidently estimate historical bi-monthly SCA from partially cloudy Landsat images. This multitemporal method is intended to guide Landsat CDR development for freshwaterscarce regions of the western US to monitor climate-driven changes in mountain snowpack extent.

Topoclimatological and snowhydrological survey of Switzerland

NASA Technical Reports Server (NTRS)

Winiger, M. (Principal Investigator)

1980-01-01

The author has identified the following significant results. Low temperature zones depend on the topography and the terrain coverage type (besides the meteorological situation). The usual pattern of cold zones at the bottom of the valleys, warmer belts along the valley slopes, and cold mountain tops is modified by the terrain coverage type. Rural and forested areas normally have different surface temperatures, but along a vertical profile the temperature decrease (or increase) is often of the same order of magnitude. Because there is also a close correlation between the topography and terrain coverage (high percentage of forested areas at the valley slopes up to the timber line, much less along the valley floors), the surface temperature of the warm slope zone is increased compared to a valley profile with uniform coverage.

Potential problems on I-77 concrete culvert.

DOT National Transportation Integrated Search

1976-01-01

Along a section of Interstate 77 in Carroll County, it was necessary to construct a fill approximately 256 ft deep. The flow of a mountain stream had to be carried through this massive embankment and, because of the nature of the terrain, it was deci...

Tropical Cyclone Report

DTIC Science & Technology

1989-01-01

CHULALONGKORN UNIVERSITY, BANGKOK LOS ANGELES PUBLIC LIBRARY CHUNG CHENG INSTITUTE, TAIWAN MASS INST OF TECH CITIES SERVICES OIL GAS CORP MCAS FUTENMA CIUDAD ...reached the mountainous oceanic sensible and latent heat sources . The terrain of Laos. system was downgraded to a typhoon at 190600Z, and then to a

Hypsometry of Titan

NASA Astrophysics Data System (ADS)

Lorenz, Ralph D.; Turtle, Elizabeth P.; Stiles, Bryan; Le Gall, Alice; Hayes, Alexander; Aharonson, Oded; Wood, Charles A.; Stofan, Ellen; Kirk, Randy

2011-01-01

Cassini RADAR topography data are used to evaluate Titan's hypsometric profile, and to make comparisons with other planetary bodies. Titan's hypsogram is unimodal and strikingly narrow compared with the terrestrial planets. To investigate topographic extremes, a novel variant on the classic hypsogram is introduced, with a logarithmic abscissa to highlight mountainous terrain. In such a plot, the top of the terrestrial hypsogram is quite distinct from those of Mars and Venus due to the 'glacial buzz-saw' that clips terrestrial topography above the snowline. In contrast to the positive skew seen in other hypsograms, with a long tail of positive relief due to mountains, there is an indication (weak, given the limited data for Titan so far) that the Titan hypsogram appears slightly negatively skewed, suggesting a significant population of unfilled depressions. Limited data permit only a simplistic comparison of Titan topography with other icy satellites but we find that the standard deviation of terrain height (albeit at different scales) is similar to those of Ganymede and Europa.

Integrated Precipitation and Hydrology Experiment (IPHEx)/Orographic Precipitation Processes Study Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barros, A. P.; Petersen, W.; Wilson, A. M.

2016-04-01

Three Microwave Radiometers (two 3-channel and one 2-channel) were deployed in the Southern Appalachian Mountains in western North Carolina as part of the Integrated Precipitation and Hydrology Experiment (IPHEx), which was the first National Aeronautics and Space Administration (NASA) Global Precipitation Mission (GPM) Ground Validation (GV) field campaign after the launch of the GPM Core Satellite (Barros et al. 2014). The radiometers were used along with other instrumentation to estimate the liquid water content of low-level clouds and fog. Specifically, data from the radiometers were collected to help, with other instrumentation, to characterize fog formation, evolution, and dissipation in themore » region (by monitoring the liquid water path in the column) and observe the effect of that fog on the precipitation regime. Data were collected at three locations in the Southern Appalachians, specifically western North Carolina: a valley in the inner mountain region, a valley in the open mountain pass region, and a ridge in the inner region. This project contributes to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility mission by providing in situ observations designed to improve the understanding of clouds and precipitation processes in complex terrain. The end goal is to use this improved understanding of physical processes to improve remote-sensing algorithms and representations of orographic precipitation microphysics in climate and earth system models.« less

Spatial distribution of Qinghai spruce forests and the thresholds of influencing factors in a small catchment, Qilian Mountains, northwest China.

PubMed

Yang, Wenjuan; Wang, Yanhui; Wang, Shunli; Webb, Ashley A; Yu, Pengtao; Liu, Xiande; Zhang, Xuelong

2017-07-17

Forest restoration in dryland mountainous areas is extremely difficult due to dry climate, complex topography and accelerating climate change. Thus, exact identification of suitable sites is required. This study at a small watershed of Qilian Mountains, Northwest China, aimed to determine the important factors and their thresholds limiting the spatial distribution of forests of Qinghai spruce (Picea crassifolia), a locally dominant tree species. The watershed was divided into 342 spatial units. Their location, terrain and vegetation characteristics were recorded. Statistical analysis showed that the potential distribution area of Qinghai spruce forests is within an ellipse with the axes of elevation (from 2673.6 to 3202.2 m a.s.l.) and slope aspect (from -162.1° to 75.1° deviated from North). Within this ellipse, the forested sites have a soil thickness ≥40 cm, and slope positions of lower-slope, lower- or middle-slope, anywhere if the elevation is <2800, 2800-2900, >2900 m a.s.l, respectively. The corresponding mean annual air temperature at upper elevation boundary is -2.69 °C, while the mean annual precipitation at lower elevation boundary is 374 (331) mm within the small watershed (study area). The high prediction accuracy using these 4 factors can help to identify suitable sites and increase the success of afforestation.

Thermal circulation patterns and turbulent fluxes along steep mountain slopes

NASA Astrophysics Data System (ADS)

Nadeau, D. F.; Pardyjak, E.; Higgins, C. W.; Huwald, H.; Baerenbold, F.; Parlange, M. B.

2010-12-01

In hydrology, it is crucial to understand the atmospheric flow dynamics in mountainous terrain to predict turbulent exchanges of heat and moisture accurately at the regional scale. Under clear sky and weak synoptic conditions, these land-atmosphere interactions are driven by thermal circulations that take place over a strong diurnal cycle. During the day, winds travel up the mountain slopes and at night, they travel down toward to the bottom of the valley. Little is known about how the transition between these two regimes takes place over steep slopes. The Slope Experiment at La Fouly (SELF) in the Swiss Alps was designed to investigate these transition periods throughout summer 2010. In this paper, we will present the first results obtained from this field campaign. Data from a network of 16 wireless surface stations is used to define catchment wide micrometeorological processes such as slope and valley wind system development, while detailed measurements of the turbulent processes on a steep idealized slope (20 to 45 degrees) were also made. The slope was instrumented along a transect with four towers (including a surface energy budget station and 10 m tower with sonic anemometers), 13 surface temperature measurement stations and a tethered balloon system to capture the complex interplay between surface and atmosphere. Initial data presented will include basic circulation pattern development and measurements of the turbulent fluxes of water vapor, heat and momentum on the slope.

Large eddy simulation for atmospheric boundary layer flow over flat and complex terrains

NASA Astrophysics Data System (ADS)

Han, Yi; Stoellinger, Michael; Naughton, Jonathan

2016-09-01

In this work, we present Large Eddy Simulation (LES) results of atmospheric boundary layer (ABL) flow over complex terrain with neutral stratification using the OpenFOAM-based simulator for on/offshore wind farm applications (SOWFA). The complete work flow to investigate the LES for the ABL over real complex terrain is described including meteorological-tower data analysis, mesh generation and case set-up. New boundary conditions for the lateral and top boundaries are developed and validated to allow inflow and outflow as required in complex terrain simulations. The turbulent inflow data for the terrain simulation is generated using a precursor simulation of a flat and neutral ABL. Conditionally averaged met-tower data is used to specify the conditions for the flat precursor simulation and is also used for comparison with the simulation results of the terrain LES. A qualitative analysis of the simulation results reveals boundary layer separation and recirculation downstream of a prominent ridge that runs across the simulation domain. Comparisons of mean wind speed, standard deviation and direction between the computed results and the conditionally averaged tower data show a reasonable agreement.

Regional geomorphology and history of Titan's Xanadu province

USGS Publications Warehouse

Radebaugh, J.; Lorenz, R.D.; Wall, S.D.; Kirk, R.L.; Wood, C.A.; Lunine, J.I.; Stofan, E.R.; Lopes, R M.C.; Valora, P.; Farr, T.G.; Hayes, A.; Stiles, B.; Mitri, Giuseppe; Zebker, H.; Janssen, M.; Wye, L.; LeGall, A.; Mitchell, K.L.; Paganelli, F.; West, R.D.; Schaller, E.L.; ,

2011-01-01

Titan's enigmatic Xanadu province has been seen in some detail with instruments from the Cassini spacecraft. The region contains some of the most rugged, mountainous terrain on Titan, with relief over 2000 m. Xanadu contains evolved and integrated river channels, impact craters, and dry basins filled with smooth, radar-dark material, perhaps sediments from past lake beds. Arcuate and aligned mountain chains give evidence of compressional tectonism, yet the overall elevation of Xanadu is puzzlingly low compared to surrounding sand seas. Lineations associated with mountain fronts and valley floors give evidence of extension that probably contributed to this regional lowering. Several locations on Xanadu's western and southern margins contain flow-like features that may be cryovolcanic in origin, perhaps ascended from lithospheric faults related to regional downdropping late in its history. Radiometry and scatterometry observations are consistent with a water–ice or water–ammonia–ice composition to its exposed, eroded, fractured bedrock; both microwave and visible to near-infrared (v-nIR) data indicate a thin overcoating of organics, likely derived from the atmosphere. We suggest Xanadu is one of the oldest terrains on Titan and that its origin and evolution have been controlled and shaped by compressional and then extensional tectonism in the icy crust and ongoing erosion by methane rainfall.

Automated thematic mapping and change detection of ERTS-A images. [farmlands, cities, and mountain identification in Utah, Washington, Arizona, and California

NASA Technical Reports Server (NTRS)

Gramenopoulos, N. (Principal Investigator)

1974-01-01

The author has identified the following significant results. A diffraction pattern analysis of MSS images led to the development of spatial signatures for farm land, urban areas and mountains. Four spatial features are employed to describe the spatial characteristics of image cells in the digital data. Three spectral features are combined with the spatial features to form a seven dimensional vector describing each cell. Then, the classification of the feature vectors is accomplished by using the maximum likelihood criterion. It was determined that the recognition accuracy with the maximum likelihood criterion depends on the statistics of the feature vectors. It was also determined that for a given geographic area the statistics of the classes remain invariable for a period of a month, but vary substantially between seasons. Three ERTS-1 images from the Phoenix, Arizona area were processed, and recognition rates between 85% and 100% were obtained for the terrain classes of desert, farms, mountains, and urban areas. To eliminate the need for training data, a new clustering algorithm has been developed. Seven ERTS-1 images from four test sites have been processed through the clustering algorithm, and high recognition rates have been achieved for all terrain classes.

Interaction of Shallow Cold Surges with Topography on Scales of 100-1000 Kilometers.

NASA Astrophysics Data System (ADS)

Toth, James John

1987-09-01

A shallow cold air mass is defined as one not extending to the top of the mountain ridge with which it interacts. The structure of such an airmass is examined using both observational data and a hydrostatic version of the Colorado State University Regional Atmospheric Modeling System. The prime constraint on a shallow cold surge is that the flow must ultimately be parallel to the mountain ridge. It is found that the effects of this constraint are altered significantly by surface sensible heat flux. Cold surges are slowed during the daylight hours, a result consistent with previous observational studies in Colorado east of the Continental Divide. Two case studies are described in detail, and several other events are cited. Since observations alone do not provide a complete description of diversion of the cold air by the mountain range, numerical model simulations provide additional insight into important mechanisms. A case study on 14 June 1985 is described using observational and model data. The model development of a deep boundary layer within the frontal baroclinic zone is consistent with the observations for this and other cases. This development is due to strong surface heating. Turning off the model shortwave radiation is seen to produce a rapid southward acceleration of the surface front, with very shallow cold air behind the front. Model simulations with specified surface temperature differences confirm the importance of upward heat flux from the surface in slowing the southward movement of the cold surge. It is concluded that the slowing is not due simply to the thermal wind developing in response to the heating of higher terrain to the west. Since surface heating is distributed over a deeper layer on the warm side of the temperature discontinuity, there is frontolysis at the surface. But this modification would develop even over flat terrain. Sloping terrain introduces additional effects. Heating at the western, upslope side of the cold surge inhibits the development of pressure gradients favorable to northerly flow. A second contribution comes from westerly winds at ridgetop level. These winds are heated over the higher terrain and flow downslope, further retarding the progression of the cold air at the surface.

Influence of Terrain and Land Cover on the Isotopic Composition of Seasonal Snowpack in Rocky Mountain Headwater Catchments Affected by Bark Beetle Induced Tree Mortality

NASA Astrophysics Data System (ADS)

Kipnis, E. L.; Murphy, M.; Klatt, A. L.; Miller, S. N.; Williams, D. G.

2015-12-01

Session H103: The Hydrology-Vegetation-Climate Nexus: Identifying Process Interactions and Environmental Shifts in Mountain Catchments Influence of Terrain and Land Cover on the Isotopic Composition of Seasonal Snowpack in Rocky Mountain Headwater Catchments Affected by Bark Beetle Induced Tree Mortality Evan L Kipnis, Melanie A Murphey, Alan Klatt, Scott N Miller, David G Williams Snowpack accumulation and ablation remain difficult to estimate in forested headwater catchments. How physical terrain and forest cover separately and interactively influence spatial patterns of snow accumulation and ablation largely shapes the hydrologic response to land cover disturbances. Analysis of water isotopes in snowpack provides a powerful tool for examining integrated effects of water vapor exchange, selective redistribution, and melt. Snow water equivalence (SWE), δ2H, δ18O and deuterium excess (D-excess) of snowpack were examined throughout winter 2013-2014 across two headwater catchments impacted by bark beetle induced tree mortality. A USGS 10m DEM and a derived land cover product from 1m NAIP imagery were used to examine the effects of terrain features (e.g., elevation, slope, aspect) and canopy disturbance (e.g., live, bark-beetle killed) as predictors of D-excess, an expression of kinetic isotope effects, in snowpack. A weighting of Akaike's Information Criterion (AIC) values from multiple spatially lagged regression models describing D-excess variation for peak snowpack revealed strong effects of elevation and canopy mortality, and weaker, but significant effects of aspect and slope. Snowpack D-excess was lower in beetle-killed canopy patches compared to live green canopy patches, and at lower compared to high elevation locations, suggesting that integrated isotopic effects of vapor exchange, vertical advection of melted snow, and selective accumulation and redistribution varied systematically across the two catchments. The observed patterns illustrate the potential for using D-excess to identify origins and timing of snowmelt runoff in streams and assessing the relative magnitude of different accumulation and ablation processes in snowpack evolution.

Evaluation of wintertime precipitation forecasts over the Australian Snowy Mountains

NASA Astrophysics Data System (ADS)

Huang, Yi; Chubb, Thomas; Sarmadi, Fahimeh; Siems, Steven T.; Manton, Michael J.; Franklin, Charmaine N.; Ebert, Elizabeth

2018-07-01

This study evaluates the Australian Community Climate and Earth-System Simulator (ACCESS) Numerical Weather Prediction system in forecasting precipitation across the Australian Snowy Mountains for two cool seasons. Metrics based on seasonal accumulated and daily precipitation show that the model is able to reproduce the observed domain-mean accumulated precipitation reasonably well (with a slight overestimation), but this is, in part, due to a compensation of various errors. Both the frequency and intensity of the heavy precipitation days (domain-mean daily precipitation >5 mm day-1) are overrepresented, particularly over the complex terrain and high-elevation areas, whereas the frequency of the very light precipitation days (domain-mean daily precipitation <1 mm day-1) is underestimated, primarily over lower-elevation areas both upwind and downwind of the mountains. Most of the precipitation is forecasted by the grid-scale precipitation scheme, with appreciable snowfalls predicted over the high elevations. The model also demonstrates appreciable skill in reproducing the synoptic regimes. The proportion of the forecast precipitation for each regime is comparable to the observations, although the orographic enhancement over the western slopes of the mountains is more pronounced in the forecasts, particularly for the wetter regimes. An examination on the effect of the lower-atmosphere stability suggests that most of the precipitation (50-70% over the high elevations) is produced under the "unblocked" condition, which is diagnosed 31% of the time. The remainder is produced under the "blocked" condition. Combined with a case study, potential sources of error associated with the forecast precipitation biases are also discussed.

Aeromagnetic Survey of the Amargosa Desert, Nevada and California: A Tool for Understanding Near-Surface Geology and Hydrology

USGS Publications Warehouse

Blakely, Richard J.; Langenheim, V.E.; Ponce, David A.; Dixon, Gary L.

2000-01-01

A high-resolution aeromagnetic survey of the Amargosa Desert and surrounding areas provides insights into the buried geology of this structurally complex region. The survey covers an area of approximately 7,700 km2 (2,970 mi2), extending from Beatty, Nevada, to south of Shoshone, California, and includes parts of the Nevada Test Site and Death Valley National Park. Aeromagnetic flight lines were oriented east-west, spaced 400 m (0.25 mi) apart, and flown at an altitude of 150 m (500 ft) above terrain, or as low as permitted by safety considerations. Characteristic magnetic anomalies occur over volcanic terranes, such as Yucca Mountain and the Greenwater Range, and over Proterozoic basement rocks, such as Bare Mountain and the Black Mountains. Linear magnetic anomalies caused by offsets of volcanic rocks permit detailed mapping of shallow faults in volcanic terranes. Of particular interest are subtle anomalies that overlie alluvial deposits at Devils Hole and Pahrump Valley. Alignments of springs along magnetic anomalies at these locales suggest that these anomalies are caused by faults that cut the alluvium, displace magnetic rocks at depth, and eventually influence ground-water flow. Linear magnetic anomalies over the Funeral Mountains appear to coincide with a prominent set of north-northeast-striking faults that cut the Precambrian Stirling Quartzite, rocks that are typically nonmagnetic. The position and orientation of these anomalies with respect to springs north of Furnace Creek suggest that the faults may act as conduits for the flow of water from the north into Death Valley, but the mineralogical cause of the anomalies is unknown.

Identifying pathways for improving household food self-sufficiency outcomes in the hills of Nepal

USDA-ARS?s Scientific Manuscript database

Maintaining and improving food security in mountain regions is an ongoing challenge. There are many facets to the problem, including comparatively high levels of system diversity and crop-livestock integration, challenging terrain and transportation bottlenecks, declining labor availability due to o...

Soil erosion and significance for carbon fluxes in a mountainous Mediterranean-climate watershed.

PubMed

Smith, S V; Bullock, S H; Hinojosa-Corona, A; Franco-Vizcaíno, E; Escoto-Rodríguez, M; Kretzschmar, T G; Farfán, L M; Salazar-Ceseña, J M

2007-07-01

In topographically complex terrains, downslope movement of soil organic carbon (OC) can influence local carbon balance. The primary purpose of the present analysis is to compare the magnitude of OC displacement by erosion with ecosystem metabolism in such a complex terrain. Does erosion matter in this ecosystem carbon balance? We have used the Revised Universal Soil Loss Equation (RUSLE) erosion model to estimate lateral fluxes of OC in a watershed in northwestern Mexico. The watershed (4900 km2) has an average slope of 10 degrees +/- 9 degrees (mean +/- SD); 45% is >10 degrees, and 3% is >30 degrees. Land cover is primarily shrublands (69%) and agricultural lands (22%). Estimated bulk soil erosion averages 1350 Mg x km(-2) x yr(-1). We estimate that there is insignificant erosion on slopes < 2 degrees and that 20% of the area can be considered depositional. Estimated OC erosion rates are 10 Mg x km(-2) x yr(-1) for areas steeper than 2 degrees. Over the entire area, erosion is approximately 50% higher on shrublands than on agricultural lands, but within slope classes, erosion rates are more rapid on agricultural areas. For the whole system, estimated OC erosion is approximately 2% of net primary production (NPP), increasing in high-slope areas to approximately 3% of NPP. Deposition of eroded OC in low-slope areas is approximately 10% of low-slope NPP. Soil OC movement from erosional slopes to alluvial fans alters the mosaic of OC metabolism and storage across the landscape.

Design of a WSN for the Sampling of Environmental Variability in Complex Terrain

PubMed Central

Martín-Tardío, Miguel A.; Felicísimo, Ángel M.

2014-01-01

In-situ environmental parameter measurements using sensor systems connected to a wireless network have become widespread, but the problem of monitoring large and mountainous areas by means of a wireless sensor network (WSN) is not well resolved. The main reasons for this are: (1) the environmental variability distribution is unknown in the field; (2) without this knowledge, a huge number of sensors would be necessary to ensure the complete coverage of the environmental variability and (3) WSN design requirements, for example, effective connectivity (intervisibility), limiting distances and controlled redundancy, are usually solved by trial and error. Using temperature as the target environmental variable, we propose: (1) a method to determine the homogeneous environmental classes to be sampled using the digital elevation model (DEM) and geometric simulations and (2) a procedure to determine an effective WSN design in complex terrain in terms of the number of sensors, redundancy, cost and spatial distribution. The proposed methodology, based on geographic information systems and binary integer programming can be easily adapted to a wide range of applications that need exhaustive and continuous environmental monitoring with high spatial resolution. The results show that the WSN design is perfectly suited to the topography and the technical specifications of the sensors, and provides a complete coverage of the environmental variability in terms of Sun exposure. However these results still need be validated in the field and the proposed procedure must be refined. PMID:25412218

BLANCO MOUNTAIN AND BLACK CANYON ROADLESS AREAS, CALIFORNIA.

USGS Publications Warehouse

Diggles, Michael F.; Rains, Richard L.

1984-01-01

The mineral survey of the Blanco Mountain and Black Canyon Roadless Areas, California indicated that areas of probable and substantiated mineral-resource potential exist only in the Black Canyon Roadless Area. Gold with moderate amounts of lead, silver, zinc, and tungsten, occurs in vein deposits and in tactite. The nature of the geological terrain indicates little likelihood for the occurrence of energy resources in the roadless areas. Detailed geologic mapping might better define the extent of gold mineralization. Detailed stream-sediment sampling and analysis of heavy-mineral concentrations could better define tungsten resource potential.

Classification of vegetation communities in the Battle Mountain SE quadrangle, Nevada with MSS digital data

NASA Technical Reports Server (NTRS)

Ridd, M. K.; Ramsey, R. D.; Douglass, G. E.; Merola, J. A.

1984-01-01

LANDSAT MSS digital data were utilized to identify vegetation types in an area of Battle Mountain SE in northern Nevada. Ways in which terrain data may improve spectral classification were investigated. The basic data set was a CCT of LANDSAT scene 82233617450, dated 15 June 1981. Seventeen ecotypic classifications were identified in the study area on the basis of field investigations. The percent cover by life form and non-living material for the 17 classes is summarized along with the percent cover by species for the 17 classes.

Enhancement in secondary particulate matter production due to mountain trapping

NASA Astrophysics Data System (ADS)

Yao, Teng; Fung, J. C. H.; Ma, H.; Lau, A. K. H.; Chan, P. W.; Yu, J. Z.; Xue, J.

2014-10-01

As China's largest economic development zone, the Pearl River Delta (PRD) is subject to particulate matter (PM) and visibility deterioration problems. Due to high PM concentration, haze days impacting ambient visibility have occurred frequently in this region. Besides visibility impairment, PM pollution also causes a negative impact on public health. These negative impacts have heightened the need to improve our understanding of the PM pollution of the PRD region. One major cause of the PRD pollution problem is cold front passages in the winter; however, the mechanism of pollution formation stays unclear. In this study, the Comprehensive Air Quality Model (CAMx) is utilized to investigate the detailed PM production and transport mechanisms in the PRD. Simulated concentrations of PM2.5 species, which have a good correlation with observation, show that sulfate and nitrate are the dominant pollutants among different PM2.5 species. Before the cold front passage a large amount of gas-phase and particle-phase pollutants are transported to the mountainous regions in the north of the PRD, and become trapped by the terrain. Over the mountain regions, cloud driven by upwelling flow promotes aqueous-phase reactions including oxidations of PM precursors such as SO2 and NO2. By this process, production of secondary PM is enhanced. When the cold front continues to advance further south, PM is transported to the PRD cities, and suppressed into a thin layer near the ground by a low planetary boundary layer (PBL). Thus high PM concentration episodes take place in the PRD cities. After examining production and transportation pathways, this study presents that the complex terrain configuration would block pollutant dispersion, provide cloudy environment, and advance secondary PM production. Previous studies have pointed out that pollution emitted from outside this region largely influences the air quality in the PRD; however, this study shows that pollutants from the outside could be originated from the PRD and transported back resulting in significant increase of secondary PM concentration, and provides new insight into PM production and transport mechanism in the PRD.

Quantifying Heterogeneities in Soil Cover and Weathering in the Bitterroot and Sapphire Mountains, Montana: Implications for Glacial Legacies and their Morphologic Control on Soil Formation

NASA Astrophysics Data System (ADS)

Benjaram, S. S.; Dixon, J. L.

2017-12-01

To what extent is chemical weathering governed by a landscape's topography? Quantifying chemical weathering in both steep rocky landscapes and soil-mantled landscapes requires describing heterogeneity in soil and rock cover at local and landscape scales. Two neighboring mountain ranges in the northern Rockies of western Montana, USA, provide an ideal natural laboratory in which to investigate the relationship between soil chemical weathering, persistence of soil cover, and topography. We focus our work in the previously glaciated Bitterroot Mountains, which consist of steep, rock-dominated hillslopes, and the neighboring unglaciated Sapphire Mountains, which display convex, soil-mantled hillslopes. Soil thickness measurements, soil and rock geochemistry, and digital terrain analysis reveal that soils in the rock-dominated Bitterroot Mountains are only slightly less weathered than those in the Sapphire Mountains. However, these differences are magnified when adjusted for rock fragments at a local scale and bedrock cover at a landscape scale, using our newly developed metric, the rock-adjusted chemical depletion fraction (RACDF) and rock-adjusted mass transfer coefficient (RA τ). The Bitterroots overall are 30% less weathered than the Sapphires despite higher mean annual precipitation in the former, with an average rock-adjusted CDF of 0.38 in the postglacial Bitterroots catchment and 0.61 in the nonglacial Sapphire catchment, suggesting that 38% of rock mass is lost in the conversion to soil in the Bitterroots, whereas 61% of rock mass is lost in the nonglaciated Sapphires. Because the previously glaciated Bitterroots are less weathered despite being wetter, we conclude that the glacial history of this landscape exerts more influence on soil chemical weathering than does modern climate. However, while previous studies have correlated weathering intensity with topographic parameters such as slope gradient, we find little topographic indication of specific controls on weathering in these complex systems.

Discrepancy Between ASTER- and MODIS- Derived Land Surface Temperatures: Terrain Effects

PubMed Central

Liu, Yuanbo; Noumi, Yousuke; Yamaguchi, Yasushi

2009-01-01

The MODerate resolution Imaging Spectroradiometer (MODIS) and the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) are onboard the same satellite platform NASA TERRA. Both MODIS and ASTER offer routine retrieval of land surface temperatures (LSTs), and the ASTER- and MODIS-retrieved LST products have been used worldwide. Because a large fraction of the earth surface consists of mountainous areas, variations in elevation, terrain slope and aspect angles can cause biases in the retrieved LSTs. However, terrain-induced effects are generally neglected in most satellite retrievals, which may generate discrepancy between ASTER and MODIS LSTs. In this paper, we reported the terrain effects on the LST discrepancy with a case examination over a relief area at the Loess Plateau of China. Results showed that the terrain-induced effects were not major, but nevertheless important for the total LST discrepancy. A large local slope did not necessarily lead to a large LST discrepancy. The angle of emitted radiance was more important than the angle of local slope in generating the LST discrepancy. Specifically, the conventional terrain correction may be unsuitable for densely vegetated areas. The distribution of ASTER-to-MODIS emissivity suggested that the terrain correction was included in the generalized split window (GSW) based approach used to rectify MODIS LSTs. Further study should include the classification-induced uncertainty in emissivity for reliable use of satellite-retrieved LSTs over relief areas. PMID:22399955

Influence of Microclimate on Semi-Arid Montane Conifer Forest Sapflux Velocity in Complex Terrain

NASA Astrophysics Data System (ADS)

Thirouin, K. R.; Barnard, D. M.; Barnard, H. R.

2016-12-01

Microclimate variation in complex terrain is key to our understanding of large-scale climate change effects on montane ecosystems. Modern climate models forecast that semi-arid montane ecosystems in the western United States are to experience increases in temperature, number of extreme drought events, and decreases in annual snowpack, all of which will potentially influence ecosystem water, carbon, and energy balances. In this study, we developed response curves that describe the relationships between stem sapflux velocity, air temperature (Tair), incoming solar radiation (SWin), soil temperature (Tsoil), and soil moisture content (VWC) in sites of Pinus contorta and Pinus ponderosa distributed along an elevation and aspect gradient in the montane zone of the Central Rocky Mountains, Colorado, USA. Among sites we found sapflux velocity to be significantly correlated with all four environmental factors (p < 0.05), but most strongly with SWin and Tair. The response of sapflux velocity to SWin was logarithmic, whereas the response to Tair indicated a peak sapflux velocity at a site-specific temperature that declined with increasing Tair. Sapflux velocity also increased with increasing VWC, but decreased with increasing Tsoil. At south-facing sites, the initial increase in the logarithmic response curve for SWin leveled off at 150-250 W m-2, whereas for north-facing sites it leveled off at 50-125 W m-2. While the differences in the SWin response between aspects could be due to species physiological differences, the highest elevation south-facing P. contorta site behaved similarly to the south-facing P. ponderosa, suggesting that environmental drivers may dominate the response. In response to Tair, peak sapflux velocity occurred at 12-13 degrees C at all sites except the mid-slope north-facing P. contorta site, which also had the lowest Tsoil. The responses of stem sapflux velocity to climate drivers indicate that forest transpiration is regulated by microclimate gradients across small spatial scales in complex terrain, which need to be characterized in order to understand broader ecosystem dynamics and the role that large-scale climate change will play in these systems.

Trajectory and Relative Dispersion Case Studies and Statistics from the Green River Mesoscale Deformation, Dispersion, and Dissipation Program

NASA Astrophysics Data System (ADS)

Niemann, Brand Lee

A major field program to study beta-mesoscale transport and dispersion over complex mountainous terrain was conducted during 1969 with the cooperation of three government agencies at the White Sands Missile Range in central Utah. The purpose of the program was to measure simultaneously on a large number of days the synoptic and mesoscale wind fields, the relative dispersion between pairs of particle trajectories and the rate of small scale turbulence dissipation. The field program included measurements during more than 60 days in the months of March, June, and November. The large quantity of data generated from this program has been processed and analyzed to provide case studies and statistics to evaluate and refine Lagrangian variable trajectory models. The case studies selected to illustrate the complexities of mesoscale transport and dispersion over complex terrain include those with terrain blocking, lee waves, and stagnation, as well as those with large vertical wind shears and horizontal wind field deformation. The statistics of relative particle dispersion were computed and compared to the classical theories of Richardson and Batchelor and the more recent theories of Lin and Kao among others. The relative particle dispersion was generally found to increase with travel time in the alongwind and crosswind directions, but in a more oscillatory than sustained or even accelerated manner as predicted by most theories, unless substantial wind shears or finite vertical separations between particles were present. The relative particle dispersion in the vertical was generally found to be small and bounded even when substantial vertical motions due to lee waves were present because of the limiting effect of stable temperature stratification. The data show that velocity shears have a more significant effect than turbulence on relative particle dispersion and that sufficient turbulence may not always be present above the planetary boundary layer for "wind direction shear induced dispersion" to become effective horizontal dispersion by vertical mixing over the shear layer. The statistics of relative particle dispersion in the three component directions have been summarized and stratified by flow parameters for use in practical prediction problems.

Geology of Pluto and Charon Overview

NASA Astrophysics Data System (ADS)

Moore, J. M.; Stern, A.; Weaver, H. A., Jr.; Young, L. A.; Ennico Smith, K.; Olkin, C.

2015-12-01

Pluto's surface was found to be remarkably diverse in terms of its range of landforms, terrain ages, and inferred geological processes. There is a latitudinal zonation of albedo. The conspicuous bright albedo heart-shaped feature informally named Tombaugh Regio is comprised of several terrain types. Most striking is Texas-sized Sputnik Planum, which is apparently level, has no observable craters, and is divided by polygons and ovoids bounded by shallow troughs. Small smooth hills are seen in some of the polygon-bounding troughs. These hills could either be extruded or exposed by erosion. Sputnik Planum polygon/ovoid formation hypotheses range from convection to contraction, but convection is currently favored. There is evidence of flow of plains material around obstacles. Mountains, especially those seen south of Sputnik Planum, exhibit too much relief to be made of CH4, CO, or N2, and thus are probably composed of H2O-ice basement material. The north contact of Sputnik Planum abuts a scarp, above which is heavily modified cratered terrain. Pluto's large moon Charon is generally heavily to moderately cratered. There is a mysterious structure in the arctic. Charon's surface is crossed by an extensive system of rift faults and graben. Some regions are smoother and less cratered, reminiscent of lunar maria. On such a plain are large isolated block mountains surrounded by moats. At this conference we will present highlights of the latest observations and analysis.

Simulation and Analysis of Topographic Effect on Land Surface Albedo over Mountainous Areas

NASA Astrophysics Data System (ADS)

Hao, D.; Wen, J.; Xiao, Q.

2017-12-01

Land surface albedo is one of the significant geophysical variables affecting the Earth's climate and controlling the surface radiation budget. Topography leads to the formation of shadows and the redistribution of incident radiation, which complicates the modeling and estimation of the land surface albedo. Some studies show that neglecting the topography effect may lead to significant bias in estimating the land surface albedo for the sloping terrain. However, for the composite sloping terrain, the topographic effects on the albedo remain unclear. Accurately estimating the sub-topographic effect on the land surface albedo over the composite sloping terrain presents a challenge for remote sensing modeling and applications. In our study, we focus on the development of a simplified estimation method for land surface albedo including black-sky albedo (BSA) and white-sky albedo (WSA) of the composite sloping terrain at a kilometer scale based on the fine scale DEM (30m) and quantitatively investigate and understand the topographic effects on the albedo. The albedo is affected by various factors such as solar zenith angle (SZA), solar azimuth angle (SAA), shadows, terrain occlusion, and slope and aspect distribution of the micro-slopes. When SZA is 30°, the absolute and relative deviations between the BSA of flat terrain and that of rugged terrain reaches 0.12 and 50%, respectively. When the mean slope of the terrain is 30.63° and SZA=30°, the absolute deviation of BSA caused by SAA can reach 0.04. The maximal relative and relative deviation between the WSA of flat terrain and that of rugged terrain reaches 0.08 and 50%. These results demonstrate that the topographic effect has to be taken into account in the albedo estimation.

Fuels management in the Subtropical Mountains Division

Treesearch

James M. Guldin

2012-01-01

The heterogeneity of the forests west of the Mississippi River in the Southern United States is strongly influenced by physiography and topography. The west Gulf Coastal Plain of southern Arkansas, northwestern Louisiana, and eastern Texas features highly productive pine-dominated forests (Pinus spp.) on gentle terrain that are interspersed by major...

Innovative Roadway Design for Recreation Areas.

DTIC Science & Technology

1982-02-01

Volume Roadways by Terrain Condition (Kearney, 1979) DHV* Maximum Grade (M) ( vph ) Level Rolling Mountainous 100 7 10 12 100-400 7 9 10 400 6 7 9 * DHV...design hourly volume; vph = vehicles per hour. j. Design of the vertical alignment is also affected by using the reduced sight distances discussed

Site descriptions: Cypress Creek, Davis Canyon, Deaf Smith, Hanford Reference, Lavender Canyon, Richton Dome, Swisher, Vacherie Dome, Yucca Mountain. Revision

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1986-04-01

The following information is given about the various sites: location (state and county), terrain, climate, weather, endangered plants and animals; nearest town, population, nearest railway, nearest interstate highway, economy, density within 50 miles, owners, and historical sites. (LM)

Hydogeomorphic Processes in Mountainous Terrain: Effects of Land Management and Implications for Sustainability and Hazards

EPA Science Inventory

The evolving science of hydrogeomorphology encompasses the interaction of water with landforms in time and space. This includes the processes of surface and mass erosion as well as the effects of land management. These hydrogeomorphic processes and management effects are examined...

Investigation of techniques for inventorying forested regions. Volume 2: Forestry information system requirements and joint use of remotely sensed and ancillary data

NASA Technical Reports Server (NTRS)

Nalepka, R. F. (Principal Investigator); Cicone, R. C.; Malila, W. A.; Crist, E. P.

1977-01-01

The author has identified the following significant results. Effects of terrain topography in mountainous forested regions on LANDSAT signals and classifier training were found to be significant. The aspect of sloping terrain relative to the sun's azimuth was the major cause of variability. A relative insolation factor could be defined which, in a single variable, represents the joint effects of slope and aspect and solar geometry on irradiance. Forest canopy reflectances were bound, both through simulation, and empirically, to have nondiffuse reflectance characteristics. Training procedures could be improved by stratifying in the space of ancillary variables and training in each stratum. Application of the Tasselled-Cap transformation for LANDSAT data acquired over forested terrain could provide a viable technique for data compression and convenient physical interpretations.

Impact of spatial variation in snow water equivalent and snow ablation on spring snowcover depletion over an alpine ridge

NASA Astrophysics Data System (ADS)

Schirmer, Michael; Harder, Phillip; Pomeroy, John

2016-04-01

The spatial and temporal dynamics of mountain snowmelt are controlled by the spatial distribution of snow accumulation and redistribution and the pattern of melt energy applied to this snowcover. In order to better quantify the spatial variations of accumulation and ablation, Structure-from-Motion techniques were applied to sequential aerial photographs of an alpine ridge in the Canadian Rocky Mountains taken from an Unmanned Aerial Vehicle (UAV). Seven spatial maps of snow depth and changes to depth during late melt (May-July) were generated at very high resolutions covering an area of 800 x 600 m. The accuracy was assessed with over 100 GPS measurements and RMSE were found to be less than 10 cm. Low resolution manual measurements of density permitted calculation of snow water equivalent (SWE) and change in SWE (ablation rate). The results indicate a highly variable initial SWE distribution, which was five times more variable than the spatial variation in ablation rate. Spatial variation in ablation rate was still substantial, with a factor of two difference between north and south aspects and small scale variations due to local dust deposition. However, the impact of spatial variations in ablation rate on the snowcover depletion curve could not be discerned. The reason for this is that only a weak spatial correlation developed between SWE and ablation rate. These findings suggest that despite substantial variations in ablation rate, snowcover depletion curve calculations should emphasize the spatial variation of initial SWE rather than the variation in ablation rate. While there is scientific evidence from other field studies that support this, there are also studies that suggest that spatial variations in ablation rate can influence snowcover depletion curves in complex terrain, particularly in early melt. The development of UAV photogrammetry has provided an opportunity for further detailed measurement of ablation rates, SWE and snowcover depletion over complex terrain and UAV field studies are recommended to clarify the relative importance of SWE and melt variability on snowcover depletion in various environmental conditions.

Geomorphological Map of the South Belet Region of Titan: An Exploration of Mid-Latitude-to-Pole Transition Zones

NASA Astrophysics Data System (ADS)

Schoenfeld, A.; Lopes, R.; Malaska, M.; Solomonidou, A.

2017-12-01

We carried out detailed geomorphological mapping of Titan's mid-latitude region south of the Belet Sand Sea. We used radar data collected by Cassini's Synthetic Aperture Radar (SAR) as our basemap, supplemented by images from VIMS, ISS, SARtopo, and microwave emissivity datasets. We mapped at a scale of 1:800,000 in all areas of the South Belet region covered by SAR swaths, taking into consideration the 300 m/pixel resolution of the swaths. For the mid-latitudes, we have defined five broad classes of terrains following Malaska et al. (2015). These terrain classes are craters, hummocky/mountainous, labyrinth, plains, and dunes. We have found that the hummocky/mountainous terrains are the oldest, with a radiometric signature consistent with icy materials. Dunes are the youngest units and return a radiometric signature consistent with organic sediments. We find that the South Belet region is covered primarily by the dune and plain units typical of Titan's mid-latitudes (Malaska et al. 2015). Previous mapping efforts of the mid-latitude regions of Titan (Lopes et al. 2016; Malaska et al. 2015) have indicated that these regions are predominately modified and influenced by aeolian activities. A plains unit designated "scalloped plains" is prominently featured between the 50°S and 60°S latitudes of this region. In this area we also find a terrain unit designated "dark irregular plains" that has been interpreted as damp materials saturated with liquid hydrocarbons (Malaska et al 2015; Hayes et al. 2008). We also note a higher occurrence of fluvial channels starting at this latitude zone and extending poleward. We suggest that these features demark the transition zone between mid-latitude/equatorial aeolian-dominated processes and fluvial-dominated processes prevailing at the poles.

Preferential Deposition of Snow in Mountains Revisited

NASA Astrophysics Data System (ADS)

Lehning, M.; Comola, F.

2017-12-01

Inhomogeneous snow accumulation in mountainous terrain is caused by precipitation gradients, spatial deposition differences as well as snow transport. The effect of spatially varying deposition as a function of near-surface flow - particle interactions has had some attention in the last decade but different groups have found conflicting results on both the relative magnitude of the effect as well as the resulting snow distribution patterns. Since in the field and through measurements it is difficult to separate preferential deposition from the other two processes, the investigation needs to rely on modellig. We present a new and complete model of flow - particle dynamics, which combines large eddy flow field simulations (LES) with Lagrangian stochastic modelling (LSM) over topography of varying complexity. Using a non-dimensionalized formulation of flow - particle interactions, we present systematic investigations on how particle properties (inertia, shape), flow properties (wind speed) and topography (height, width) influence the magnitude and distribution pattern of snow deposition. It is shown that dependent on Froude and Stokes numbers, very different deposition patterns can result with maximum deposition either in the windward or lee of a ridge and that dendridic snow is behaving similar to inertialess tracers.

The T-REX valley wind intercomparison project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidli, J; Billings, B J; Burton, R

2008-08-07

An accurate simulation of the evolution of the atmospheric boundary layer is very important, as the evolution of the boundary layer sets the stage for many weather phenomena, such as deep convection. Over mountain areas the evolution of the boundary layer is particularly complex, due to the nonlinear interaction between boundary layer turbulence and thermally-induced mesoscale wind systems, such as the slope and valley winds. As the horizontal resolution of operational forecasts progresses to finer and finer resolution, more and more of the thermally-induced mesoscale wind systems can be explicitly resolved, and it is very timely to document the currentmore » state-of-the-art of mesoscale models at simulating the coupled evolution of the mountain boundary layer and the valley wind system. In this paper we present an intercomparison of valley wind simulations for an idealized valley-plain configuration using eight state-of-the-art mesoscale models with a grid spacing of 1 km. Different sets of three-dimensional simulations are used to explore the effects of varying model dynamical cores and physical parameterizations. This intercomparison project was conducted as part of the Terrain-induced Rotor Experiment (T-REX; Grubisic et al., 2008).« less

Mediterranean summer climate and the importance of Middle-East Topography

NASA Astrophysics Data System (ADS)

Simpson, Isla; Seager, Richard; Shaw, Tiffany; Ting, Mingfang

2015-04-01

In summer, the atmospheric circulation over the Mediterranean is characterized by localized intense subsidence and low level northerlies over the central- to eastern portion of the basin. Here, simulations with the Community Atmosphere Model, version 5 are used to investigate the influence of the elevated terrain of North Africa and the Middle East on this summertime circulation. This builds on previous work that recognized a role for North African topography in localizing the Mediterranean subsidence. By flattening the two regions of elevated terrain in the model it is demonstrated that, while they both conspire to produce about 30% of the summertime subsidence, contrary to previous work, the mountains of the Middle-East dominate in this topographic contribution by far. This topography, consisting primarily of the Zagros Mountain range, alters the circulation throughout the depth of the troposphere over the Mediterranean, and further East. The model results suggest that about 20% of the Mediterranean summertime moisture deficit can be attributed to this mountain induced circulation. This topography, therefore, plays an important role in the climate of the Mediterranean and the large scale circulation over the rest of Eurasia during the summer. Further stationary wave modelling reveals that the mountain influence is produced via mechanical forcing of the flow. The greatest influence of the topography occurs when the low level incident flow is easterly, as happens during the summer, primarily due to the presence of condensational heating over Asia. During other seasons, when the low level incident flow is westerly, the influence of Middle-East topography on the Mediterranean is negligible.

Mapping topographic plant location properties using a dense matching approach

NASA Astrophysics Data System (ADS)

Niederheiser, Robert; Rutzinger, Martin; Lamprecht, Andrea; Bardy-Durchhalter, Manfred; Pauli, Harald; Winkler, Manuela

2017-04-01

Within the project MEDIALPS (Disentangling anthropogenic drivers of climate change impacts on alpine plant species: Alps vs. Mediterranean mountains) six regions in Alpine and in Mediterranean mountain regions are investigated to assess how plant species respond to climate change. The project is embedded in the Global Observation Research Initiative in Alpine Environments (GLORIA), which is a well-established global monitoring initiative for systematic observation of changes in the plant species composition and soil temperature on mountain summits worldwide to discern accelerating climate change pressures on these fragile alpine ecosystems. Close-range sensing techniques such as terrestrial photogrammetry are well suited for mapping terrain topography of small areas with high resolution. Lightweight equipment, flexible positioning for image acquisition in the field, and independence on weather conditions (i.e. wind) make this a feasible method for in-situ data collection. New developments of dense matching approaches allow high quality 3D terrain mapping with less requirements for field set-up. However, challenges occur in post-processing and required data storage if many sites have to be mapped. Within MEDIALPS dense matching is used for mapping high resolution topography for 284 3x3 meter plots deriving information on vegetation coverage, roughness, slope, aspect and modelled solar radiation. This information helps identifying types of topography-dependent ecological growing conditions and evaluating the potential for existing refugial locations for specific plant species under climate change. This research is conducted within the project MEDIALPS - Disentangling anthropogenic drivers of climate change impacts on alpine plant species: Alps vs. Mediterranean mountains funded by the Earth System Sciences Programme of the Austrian Academy of Sciences.

Nomadic ecology shaped the highland geography of Asia's Silk Roads.

PubMed

Frachetti, Michael D; Smith, C Evan; Traub, Cynthia M; Williams, Tim

2017-03-08

There are many unanswered questions about the evolution of the ancient 'Silk Roads' across Asia. This is especially the case in their mountainous stretches, where harsh terrain is seen as an impediment to travel. Considering the ecology and mobility of inner Asian mountain pastoralists, we use 'flow accumulation' modelling to calculate the annual routes of nomadic societies (from 750 m to 4,000 m elevation). Aggregating 500 iterations of the model reveals a high-resolution flow network that simulates how centuries of seasonal nomadic herding could shape discrete routes of connectivity across the mountains of Asia. We then compare the locations of known high-elevation Silk Road sites with the geography of these optimized herding flows, and find a significant correspondence in mountainous regions. Thus, we argue that highland Silk Road networks (from 750 m to 4,000 m) emerged slowly in relation to long-established mobility patterns of nomadic herders in the mountains of inner Asia.

Nomadic ecology shaped the highland geography of Asia’s Silk Roads

NASA Astrophysics Data System (ADS)

Frachetti, Michael D.; Smith, C. Evan; Traub, Cynthia M.; Williams, Tim

2017-03-01

There are many unanswered questions about the evolution of the ancient ‘Silk Roads’ across Asia. This is especially the case in their mountainous stretches, where harsh terrain is seen as an impediment to travel. Considering the ecology and mobility of inner Asian mountain pastoralists, we use ‘flow accumulation’ modelling to calculate the annual routes of nomadic societies (from 750 m to 4,000 m elevation). Aggregating 500 iterations of the model reveals a high-resolution flow network that simulates how centuries of seasonal nomadic herding could shape discrete routes of connectivity across the mountains of Asia. We then compare the locations of known high-elevation Silk Road sites with the geography of these optimized herding flows, and find a significant correspondence in mountainous regions. Thus, we argue that highland Silk Road networks (from 750 m to 4,000 m) emerged slowly in relation to long-established mobility patterns of nomadic herders in the mountains of inner Asia.

[Mountain biking : Breezy ups and traumatic downs].

PubMed

Schueller, G

2010-05-01

For more than two decades the popularity of mountain biking as a national pastime as well as a competitive sport has been undiminished. However, its related risks are not monitored as closely as those, for example, of skiing. The injuries caused by mountain biking are specific and cannot be compared with those caused by other cycling sports. This is due not only to the characteristics of the terrain but also to the readiness to assume a higher risk compared to cycle racing.The particular value of radiology is in the acute trauma setting. Most often musculoskeletal lesions must be examined and digital radiography and MRI are the most useful techniques. Severe trauma of the cranium, face, spine, thorax and abdomen are primarily evaluated with CT, particularly in dedicated trauma centers. Therefore, radiology can play a role in the rapid diagnosis and optimal treatment of the trauma-related injuries of mountain biking. Thus, the unnecessarily high economical damage associated with mountain biking can be avoided.

Orographic Modification of Precipitation Processes in Hurricane Karl (2010)

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeHart, Jennifer C.; Houze, Robert A.

Airborne radar data collected within Hurricane Karl (2010) provide a high-resolution glimpse of variations in the vertical precipitation structure around complex terrain in eastern Mexico. Widespread precipitation north of Karl’s track traced the strong gradient of terrain, suggesting orographic enhancement. Although the airborne radar did not sample the period of peak precipitation, time series of surface rainfall at three locations near the inner core show greater precipitation where flow was oriented to rise over the terrain. In regions of upslope flow, radar observations reveal reflectivity enhancement within 1–2 km of the surface. The shallow nature of the enhancement points tomore » orographically generated cloud water accreted by falling drops as a mechanism consistent with prior studies, while the heterogeneous nature of the enhancement suggests shallow convection was playing a role. In contrast, regions of downslope flow were characterized by uniform reflectivity above the ground and fallstreaks originating above the melting level. Unlike most previously studied tropical cyclones passing over topography, Karl made landfall on a mountainous continent, not an island. As Karl weakened and decayed over land, the vertical structure of the radar echo deteriorated north of the storm center, and infrared satellite imagery revealed a strong reduction in the upper-level cloud coverage; however, a small region of intense convection appeared and produced locally heavy rainfall as Karl was close to dissipation. In conclusion, these results indicate that orographic modification processes in a landfalling tropical cyclone are not static, and surface precipitation is highly sensitive to the changes.« less

Orographic Modification of Precipitation Processes in Hurricane Karl (2010)

DOE PAGES

DeHart, Jennifer C.; Houze, Robert A.

2017-10-06

Airborne radar data collected within Hurricane Karl (2010) provide a high-resolution glimpse of variations in the vertical precipitation structure around complex terrain in eastern Mexico. Widespread precipitation north of Karl’s track traced the strong gradient of terrain, suggesting orographic enhancement. Although the airborne radar did not sample the period of peak precipitation, time series of surface rainfall at three locations near the inner core show greater precipitation where flow was oriented to rise over the terrain. In regions of upslope flow, radar observations reveal reflectivity enhancement within 1–2 km of the surface. The shallow nature of the enhancement points tomore » orographically generated cloud water accreted by falling drops as a mechanism consistent with prior studies, while the heterogeneous nature of the enhancement suggests shallow convection was playing a role. In contrast, regions of downslope flow were characterized by uniform reflectivity above the ground and fallstreaks originating above the melting level. Unlike most previously studied tropical cyclones passing over topography, Karl made landfall on a mountainous continent, not an island. As Karl weakened and decayed over land, the vertical structure of the radar echo deteriorated north of the storm center, and infrared satellite imagery revealed a strong reduction in the upper-level cloud coverage; however, a small region of intense convection appeared and produced locally heavy rainfall as Karl was close to dissipation. In conclusion, these results indicate that orographic modification processes in a landfalling tropical cyclone are not static, and surface precipitation is highly sensitive to the changes.« less

Ouachita Mountains, Oklahoma as seen from STS-58

NASA Image and Video Library

1993-10-30

STS058-91-058 (18 Oct-1 Nov 1993) --- In this unusually clear view, the Ouachita Mountains of southeastern Oklahoma are framed on the north by Lake Eufaula on the South Canadian River, and on the south by the Red River. Sandstone, shale and chert (similar to flint) deposited in a sea several thousand feet deep were squeezed up to form the mountains about 250 million years ago. During the ensuing time, erosion of the western end of the Ouachita Mountains has emphasized linear ridges of resistant rock in the plunging anticlines and synclines, causing relief of 800 meters (2,600 feet) or more. Clouds formed by upslope winds border both the north and south sides of one of the most dramatic plunging synclines (in a syncline the rock layers dip toward the center of the structure). Toward the west, densely forested mountains give way to gently rolling, less rocky terrain and a drier climate which is better suited to farming. The mountains centered on Broken Bow, in the lower right corner of the scene, display abundant timber clearcuts that are being regenerated.

Training in Innovative Technologies for Close-Range Sensing in Alpine Terrain

NASA Astrophysics Data System (ADS)

Rutzinger, M.; Bremer, M.; Höfle, B.; Hämmerle, M.; Lindenbergh, R.; Oude Elberink, S.; Pirotti, F.; Scaioni, M.; Wujanz, D.; Zieher, T.

2018-05-01

The 2nd international summer school "Close-range sensing techniques in Alpine terrain" was held in July 2017 in Obergurgl, Austria. Participants were trained in selected close-range sensing methods, such as photogrammetry, laser scanning and thermography. The program included keynotes, lectures and hands-on assignments combining field project planning, data acquisition, processing, quality assessment and interpretation. Close-range sensing was applied for different research questions of environmental monitoring in high mountain environments, such as geomorphologic process quantification, natural hazard management and vegetation mapping. The participants completed an online questionnaire evaluating the summer school, its content and organisation, which helps to improve future summer schools.

Pacific Northwest (PNW) Hydrologic Landscape (HL) polygons and HL code

EPA Pesticide Factsheets

A five-letter hydrologic landscape code representing five indices of hydrologic form that are related to hydrologic function: climate, seasonality, aquifer permeability, terrain, and soil permeability. Each hydrologic assessment unit is classified by one of the 81 different five-letter codes representing these indices. Polygon features in this dataset were created by aggregating (dissolving boundaries between) adjacent, similarly-coded hydrologic assessment units. Climate Classes: V-Very wet, W-Wet, M-Moist, D-Dry, S-Semiarid, A-Arid. Seasonality Sub-Classes: w-Fall or winter, s-Spring. Aquifer Permeability Classes: H-High, L-Low. Terrain Classes: M-Mountain, T-Transitional, F-Flat. Soil Permeability Classes: H-High, L-Low.

A Regional Atmospheric Continuous CO2 Network In The Rocky Mountains (Rocky RACCOON)

NASA Astrophysics Data System (ADS)

Stephens, B.; de Wekker, S.; Watt, A.; Schimel, D.

2005-12-01

We have established a continuous CO2 observing network in the Rocky Mountains, building on technological and modeling advances made during the Carbon in the Mountains Experiment (CME), to improve our understanding of regional carbon fluxes and to fill key gaps in the North American Carbon Program (NACP). We will present a description of the Rocky RACCOON network and early results from the first three sites. There are strong scientific and societal motivations for determining CO2 exchanges on regional scales. NACP aims to address these concerns through a dramatic expansion in observations and modeling capabilities over North America. Mountain forests in particular represent a significant potential net CO2 sink in the U.S. and are highly sensitive to land-use practices and climate change. However, plans for new continuous CO2 observing sites have omitted the mountain west. This resulted from expensive instrumentation in the face of limited resources, and a perception that current atmospheric transport models are not sophisticated enough to interpret CO2 measurements made in complex terrain. Through our efforts in CME, we have a new autonomous, inexpensive, and robust CO2 analysis system and are developing mountain CO2 modeling tools that will help us to overcome these obstacles. Preliminary observational and modeling results give us confidence that continuous CO2 observations from mountain top observatories will provide useful constraints on regional carbon cycling and will be valuable in the continental inverse modeling efforts planned for NACP. We began at three Colorado sites in August 2005 and hope to add three to six sites in other western states in subsequent years, utilizing existing observatories to the maximum extent possible. The first three sites are at Niwot Ridge, allowing us to have an ongoing intercomparison with flask measurements made by NOAA CMDL; at Storm Peak Laboratory near Steamboat Springs, allowing us to investigate comparisons between these two relatively nearby sites; and at Fraser Experimental Forest, allowing us to investigate nocturnal respiration rates across a large intermountain valley. Our data are available to the public on the internet in near real time to support quality control, local science, and larger scale synthesis efforts.

Lithology and structure within the basement terrain adjacent to Clark Mountains, California, mapped with calibrated data from the airborne visible/infrared imaging spectrometer

NASA Technical Reports Server (NTRS)

Green, Robert O.; Vane, Gregg

1989-01-01

The Clark Mountains in eastern California form a rugged, highly dissected area nearly 5000 ft above sea level, with Clark Mountain rising to 8000 ft. The rocks of the Clark Mountains and the Mescal Range just to the south are Paleozoic carbonate and clastic rocks, and Mesozoic clastic and volcanic rocks standing in pronounced relief above the fractured Precambrian gneisses to the east. The Permian Kaibab Limestone and the Triassic Moenkopi and Chinle Formations are exposed in the Mescal Range, which is the only place in California where these rocks, which are typical of the Colorado Plateau, are found. To the west, the mountains are bordered by the broad alluvial plains of Shadow Valley. Cima Dome, which is an erosional remnant carved on a batholithic intrusion of quartz monzonite, is found at the south end of the valley. To the east of the Clark and Mescal Mountains is found the Ivanpah Valley, in the center of which is located the Ivanpah Play. Studies of the Clark Mountains with the airborne visible/infrared imaging spectrometer are briefly described.

A computer simulation model to compute the radiation transfer of mountainous regions

NASA Astrophysics Data System (ADS)

Li, Yuguang; Zhao, Feng; Song, Rui

2011-11-01

In mountainous regions, the radiometric signal recorded at the sensor depends on a number of factors such as sun angle, atmospheric conditions, surface cover type, and topography. In this paper, a computer simulation model of radiation transfer is designed and evaluated. This model implements the Monte Carlo ray-tracing techniques and is specifically dedicated to the study of light propagation in mountainous regions. The radiative processes between sun light and the objects within the mountainous region are realized by using forward Monte Carlo ray-tracing methods. The performance of the model is evaluated through detailed comparisons with the well-established 3D computer simulation model: RGM (Radiosity-Graphics combined Model) based on the same scenes and identical spectral parameters, which shows good agreements between these two models' results. By using the newly developed computer model, series of typical mountainous scenes are generated to analyze the physical mechanism of mountainous radiation transfer. The results show that the effects of the adjacent slopes are important for deep valleys and they particularly affect shadowed pixels, and the topographic effect needs to be considered in mountainous terrain before accurate inferences from remotely sensed data can be made.

Hydromorphic soil development in the coastal temperate rainforest of Alaska

Treesearch

David V. D' Amore; Chien-Lu Ping; Paul A. Herendeen

2015-01-01

Predictive relationships between soil drainage and soil morphological features are essential for understanding hydromorphic processes in soils. The linkage between patterns of soil saturation, reduction, and reductimorphic soil properties has not been extensively studied in mountainous forested terrain. We measured soil saturation and reduction during a 4-yr period in...

Southern Appalachian Case Study

Treesearch

Charles C. van Sickle

1999-01-01

The Southern Appalachian study covers a region of 37.4 million acres. Its mountains, foothills, and valleys stretch from northern Virginia and northern West Virginia to northern Georgia and Alabama. When Native Americans came to the region, forests dominated the landscape and they still do, covering 70% of the land (Figure 32.1). Terrain characteristics are...

A Study of Bancroftian Filariasis on the Islands of Batan and Rapu Rapu, Philippines

DTIC Science & Technology

1988-06-01

difficult duefrom which cases of elephantiasis were to the mountainous terrain and absence of reported to have originated (pers. comm. Division of Disease...iis in each village exhibited elephantiasis . The local people attributed the cause to walking were infective with third-stage larvae, and in cool

49 CFR 350.309 - What activities are eligible for reimbursement under the MCSAP?

Code of Federal Regulations, 2013 CFR

2013-10-01

... an appropriate North American Standard Inspection and inspection report: (1) Enforcement of CMV size... steep grades or mountainous terrains where the weight of a CMV can significantly affect the safe.... (2) Detection of the unlawful presence of a controlled substance in a CMV or on the person of any...

49 CFR 350.309 - What activities are eligible for reimbursement under the MCSAP?

Code of Federal Regulations, 2014 CFR

2014-10-01

... an appropriate North American Standard Inspection and inspection report: (1) Enforcement of CMV size... steep grades or mountainous terrains where the weight of a CMV can significantly affect the safe.... (2) Detection of the unlawful presence of a controlled substance in a CMV or on the person of any...

49 CFR 350.309 - What activities are eligible for reimbursement under the MCSAP?

Code of Federal Regulations, 2012 CFR

2012-10-01

... an appropriate North American Standard Inspection and inspection report: (1) Enforcement of CMV size... steep grades or mountainous terrains where the weight of a CMV can significantly affect the safe.... (2) Detection of the unlawful presence of a controlled substance in a CMV or on the person of any...

A terrain-attribute based approach to assessing soil carbon sequestration in the Oregon Coast range mountains

EPA Science Inventory

Determining how to best mitigate Global Climate Change through the sequestration of atmospheric CO2 requires developing an understanding of potential ecosystem C sinks and the rates at which C can be sequestered in soils and vegetation under a variety of land uses. The largest g...

An Evaluation of Virtual Home Visits in Early Intervention: Feasibility of "Virtual Intervention"

ERIC Educational Resources Information Center

Olsen, Sue; Fiechtl, Barbara; Rule, Sarah

2012-01-01

The provision of consistent high quality home- and community-based services to children with disabilities living in rural and frontier areas is a challenge. Distance, weather, geographic terrain (mountains, canyons), and shortages of pediatric early interventionists are among the challenges to ensuring appropriate and equitable services.…

A Student-Centered Field Project Comparing NEXRAD and Rain Gauge Precipitation Values in Mountainous Terrain.

ERIC Educational Resources Information Center

Woltemade, Christopher J.; Stanitski-Martin, Diane

2002-01-01

Undergraduate students compared Next Generation Weather Radar (NEXRAD) estimates of storm total precipitation to measurements from a network of 20 rain gauges. Student researchers gained valuable experience in field data collection, global positioning systems (GPS), geographic information systems (GIS), Internet data access and downloading,…

Approximate Subgraph Isomorphism for Image Localization (Author’s Manuscript)

DTIC Science & Technology

2016-02-18

a working database for feature matching methods is nearly impossible to generate. In a proof of feasibility, Bansal et. al. [2] claim that overhead...of images in mountainous terrain. In Computer Vision–ECCV 2012, pages 517–530. Springer, 2012. 1 [2] M. Bansal , H. S. Sawhney, H. Cheng, and K

Optimal Use of TDOA Geo-Location Techniques Within the Mountainous Terrain of Turkey

DTIC Science & Technology

2012-09-01

Cross -Correlation TDOA Estimation Technique ................. 49 3. Standard Deviation...76 Figure 32. The Effect of Noise on Accuracy ........................................................ 77 Figure 33. The Effect of Noise to...finding techniques. In contrast, people have been using active location finding techniques, such as radar , for decades. When active location finding

Stump-to-truck cable logging cost equations for young-growth douglas-fir

Treesearch

Chris B. LeDoux; Roger D. Fight; Tom L. Ortman

1986-01-01

Logging cost simulators and data from logging cost studies have been assembled and converted into a series of equations that can be used to estimate the cost of logging young-growth coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) in mountainous terrain of the Pacific Northwest. These equations were...

Mountain Wave Analysis Using Fourier Methods

DTIC Science & Technology

2007-10-01

model for altitudes up to 18 km for the same location using the Hilo , Hawaii 1200 UTC rawinsonde for the background velocity and temperature profile... Hawaii terrain and atmosphere 46 for 12 Dec 2002 vii Tables 1...20 3. Three-Layer Model Specifications for Hawaii 12 December 2002 06 UTC 22 4. Three-Layer Model

Fourmile Canyon Fire Findings

Treesearch

Russell Graham; Mark Finney; Chuck McHugh; Jack Cohen; Dave Calkin; Rick Stratton; Larry Bradshaw; Ned Nikolov

2012-01-01

The Fourmile Canyon Fire burned in the fall of 2010 in the Rocky Mountain Front Range adjacent to Boulder, Colorado. The fire occurred in steep, rugged terrain, primarily on privately owned mixed ponderosa pine and Douglas-fir forests. The fire started on September 6 when the humidity of the air was very dry (¡Ö

Present and past glaciation on Pluto

NASA Astrophysics Data System (ADS)

Howard, Alan D.; Moore, Jeffrey M.; Umurhan, Orkan M.; White, Oliver L.; Anderson, Robert S.; McKinnon, William B.; Spencer, John R.; Schenk, Paul M.; Beyer, Ross A.; Stern, S. Alan; Ennico, Kimberly; Olkin, Cathy B.; Weaver, Harold A.; Young, Leslie A.; New Horizons Science Team

2017-05-01

Modern N2 ice glaciers flow from highlands to the east of the 750 × 1400 km2 lowland of Sputnik Planum [SP] and merge with the ices of similar composition on SP. We explore the possibility that glaciation may be fed by N2 sublimation from SP followed by redeposition on the highlands. The uplands to the northeast, north, and west of SP have been erosionally sculpted into a variety of dissected terrains that feature linear depressions (valleys), locally in dendritic networks. We interpret these dissected terrains to have been carved by N2 glaciers formerly covering the uplands. Depositional glacial landforms (moraines, eskers, outwash) have not been identified, however. N2 glaciation would have a different erosional manifestation because the substrate (porous water ice and CH4-rich mantles) probably has lower density than N2, and also because of the lack of freeze-thaw weathering. If sufficiently thick (1-4 km), N2 glaciers might have experienced basal melting. Past flow of N2 glaciers from the highlands into SP may have detached and transported the prominent mountainous water ice mountains along the western border of SP.

Quasi-analytical treatment of spatially averaged radiation transfer in complex terrain

NASA Astrophysics Data System (ADS)

Löwe, H.; Helbig, N.

2012-04-01

We provide a new quasi-analytical method to compute the topographic influence on the effective albedo of complex topography as required for meteorological, land-surface or climate models. We investigate radiative transfer in complex terrain via the radiosity equation on isotropic Gaussian random fields. Under controlled approximations we derive expressions for domain averages of direct, diffuse and terrain radiation and the sky view factor. Domain averaged quantities are related to a type of level-crossing probability of the random field which is approximated by longstanding results developed for acoustic scattering at ocean boundaries. This allows us to express all non-local horizon effects in terms of a local terrain parameter, namely the mean squared slope. Emerging integrals are computed numerically and fit formulas are given for practical purposes. As an implication of our approach we provide an expression for the effective albedo of complex terrain in terms of the sun elevation angle, mean squared slope, the area averaged surface albedo, and the direct-to-diffuse ratio of solar radiation. As an application, we compute the effective albedo for the Swiss Alps and discuss possible generalizations of the method.

Cloud and convection frequencies over the southeast United States as related to small-scale geographic features

NASA Technical Reports Server (NTRS)

Gibson, Harold M.; Vonder Haar, Thomas H.

1990-01-01

Based on relatively high spatial and temporal resolution satelite data collected at 0700 CST and at each hour from 1000 CST to 1700 CST during the summer of 1986, cloud and convection variations over the area from Mississippi east to Georgia and from the Gulf of Mexico north to Tennessee are discussed. The data analyses show an average maximum cloud frequency over the land areas at 1400 local time and a maximum of deep convection one hour later. Both cloudiness and deep convection are found to be at a maximum during the nocturnal hours over the Gulf of Mexico. Cloud frequency shows a strong relationship to small terrain features. Small fresh water bodies have cloud minima relative to the surroundings in the afternoon hours. Higher, steep terrain shows cloud maxima and the adjacent lower terrain exhibits afternoon cloud minima due to a divergence of mountain breeze caused by the valley.

A comparison of methods for computing the sigma-coordinate pressure gradient force for flow over sloped terrain in a hybrid theta-sigma model

NASA Technical Reports Server (NTRS)

Johnson, D. R.; Uccellini, L. W.

1983-01-01

In connection with the employment of the sigma coordinates introduced by Phillips (1957), problems can arise regarding an accurate finite-difference computation of the pressure gradient force. Over steeply sloped terrain, the calculation of the sigma-coordinate pressure gradient force involves computing the difference between two large terms of opposite sign which results in large truncation error. To reduce the truncation error, several finite-difference methods have been designed and implemented. The present investigation has the objective to provide another method of computing the sigma-coordinate pressure gradient force. Phillips' method is applied for the elimination of a hydrostatic component to a flux formulation. The new technique is compared with four other methods for computing the pressure gradient force. The work is motivated by the desire to use an isentropic and sigma-coordinate hybrid model for experiments designed to study flow near mountainous terrain.

Digital structural interpretation of mountain-scale photogrammetric 3D models (Kamnik Alps, Slovenia)

NASA Astrophysics Data System (ADS)

Dolžan, Erazem; Vrabec, Marko

2015-04-01

From the earliest days of geological science, mountainous terrains with their extreme topographic relief and sparse to non-existent vegetation were utilized to a great advantage for gaining 3D insight into geological structure. But whereas Alpine vistas may offer perfect panoramic views of geology, the steep mountain slopes and vertical cliffs make it very time-consuming and difficult (if not impossible) to acquire quantitative mapping data such as precisely georeferenced traces of geological boundaries and attitudes of structural planes. We faced this problem in mapping the central Kamnik Alps of northern Slovenia, which are built up from Mid to Late Triassic succession of carbonate rocks. Polyphase brittle tectonic evolution, monotonous lithology and the presence of temporally and spatially irregular facies boundary between bedded platform carbonates and massive reef limestones considerably complicate the structural interpretation of otherwise perfectly exposed, but hardly accessible massif. We used Agisoft Photoscan Structure-from-Motion photogrammetric software to process a series of overlapping high-resolution (~0.25 m ground resolution) vertical aerial photographs originally acquired by the Geodetic Authority of the Republic of Slovenia for surveying purposes, to derive very detailed 3D triangular mesh models of terrain and associated photographic textures. Phototextures are crucial for geological interpretation of the models as they provide additional levels of detail and lithological information which is not resolvable from geometrical mesh models alone. We then exported the models to Paradigm Gocad software to refine and optimize the meshing. Structural interpretation of the models, including mapping of traces and surfaces of faults and stratigraphic boundaries and determining dips of structural planes, was performed in MVE Move suite which offers a range of useful tools for digital mapping and interpretation. Photogrammetric model was complemented by georeferenced geological field data acquired along mountain trail transects, mainly using the MVE Field Move software application. In our experience, vertical aerophotos were sufficient to generate precise surface models in all but the steepest mountain cliffs. Therefore, using existing vertical photoimagery (where available) is a very cost-effective alternative to organizing shooting campaigns with rented aircraft. For handling reasonably large models (cca 3 x 3 km, up to 10 million triangles), a low-end computer workstation with mid-range professional 3D graphic card is sufficient. The biggest bottleneck is the photogrammetric processing step which is time-consuming (10s of hrs) and has large RAM requirements, although those can be offset by dividing models into smaller parts. The major problem with geological modeling software like Gocad or Move is that it at present does not handle well projecting of phototextures. Whereas Photoscan-generated orthophotos can be vertically projected onto mesh models, this results in unacceptable distortions and gaps in subvertical or overhanging parts of the mountain cliff models. A real 3D UV texture mapping method, such as implemented in Photoscan, would be required to realistically model such areas. This limitations notwithstanding, digital geological mapping of photogrammetric models of mountains is a very promising, cost- and time-effective method for rapid structural interpretation and mapping of barren mountainous terrains, particularly when it is complemented by field measurements and observations.

Earth observations Cape Town, South Africa taken during the STS-97 mission

NASA Image and Video Library

2000-12-10

STS097-711-069 (30 Nov. - 11 Dec. 2000) This view featuring Cape Town and the Western Cape Province in the Republic of South Africa was provided by one of the STS-97 astronauts using a 70mm handheld camera aboard the Earth-orbiting Space Shuttle Endeavour. The capital and largest city of Western Cape Province, Cape Town (1995 population in the urban and suburban area shows in excess of 1.9 million), is visible between False Bay (large, U-shaped bay) and a smaller bay along the Atlantic coast of the peninsula. Within the urban built-up area some of the infrastructure of Cape Town, including the city center and the harbor and waterfront facilities, can be identified near the small bay (middle left edge of the image). Table Mountain elevation of 3563 feet (1086 meters above sea level) separates the city center (north of the mountain) from the southern suburbs of Cape Town. The Cape of Good Hope, long famous as the gateway from the Atlantic Ocean to the Indian Ocean, is located at the southern tip of the claw-shaped peninsula. False Bay is a popular recreational region for the local residents of the greater Cape Town region, as well as a tourist attraction for people who live beyond the borders of South Africa. The lighter-colored terrain, mainly north of Cape Town, shows a landscape of large, cultivated field patterns. These coastal plains are separated from the interior by a chain of folded mountain ranges that include the Cedarberg (dark, linear, north/south aligned feature in the upper right corner) and the more complex, folded Herrivierberge Mountains (dark structure, right middle) that are located northeast of Cape Town.

A Comparison between Airborne and Mountaintop Cloud Microphysics

NASA Astrophysics Data System (ADS)

David, R.; Lowenthal, D. H.; Hallar, A. G.; McCubbin, I.; Avallone, L. M.; Mace, G. G.; Wang, Z.

2014-12-01

Complex terrain has a large impact on cloud dynamics and microphysics. Several studies have examined the microphysical details of orographically-enhanced clouds from either an aircraft or from a mountain top location. However, further research is needed to characterize the relationships between mountain top and airborne microphysical properties. During the winter of 2011, an airborne study, the Colorado Airborne Mixed-Phase Cloud Study (CAMPS), and a ground-based field campaign, the Storm Peak Lab (SPL) Cloud Property Validation Experiment (StormVEx) were conducted in the Park Range of the Colorado Rockies. The CAMPS study utilized the University of Wyoming King Air (UWKA) to provide airborne cloud microphysical and meteorological data on 29 flights totaling 98 flight hours over the Park Range from December 15, 2010 to February 28, 2011. The UWKA was equipped with instruments that measured both cloud droplet and ice crystal size distributions, liquid water content, total water content (vapor, liquid, and ice), and 3-dimensional wind speed and direction. The Wyoming Cloud Radar and Lidar were also deployed during the campaign. These measurements are used to characterize cloud structure upwind and above the Park Range. StormVEx measured cloud droplet, ice crystal, and aerosol size distributions at SPL, located on the west summit of Mt. Werner at 3220m MSL. The observations from SPL are used to determine mountain top cloud microphysical properties at elevations lower than the UWKA was able to sample in-situ. Comparisons showed that cloud microphysics aloft and at the surface were consistent with respect to snow growth processes while small crystal concentrations were routinely higher at the surface, suggesting ice nucleation near cloud base. The effects of aerosol concentrations and upwind stability on mountain top and downwind microphysics are considered.

Values of Deploying a Compact Polarimetric Radar to Monitor Extreme Precipitation in a Mountainous Area: Mineral County, Colorado

NASA Astrophysics Data System (ADS)

Cheong, B. L.; Kirstetter, P. E.; Yu, T. Y.; Busto, J.; Speeze, T.; Dennis, J.

2015-12-01

Precipitation in mountainous regions can trigger flash floods and landslides especially in areas affected by wildfire. Because of the small space-time scales required for observation, they remain poorly observed. A light-weighted X-band polarimetric radar can rapidly respond to the situation and provide continuous rainfall information with high resolution for flood forecast and emergency management. A preliminary assessment of added values to the operational practice in Mineral county, Colorado was performed in Fall 2014 and Summer 2015 with a transportable polarimetric radar deployed at the Lobo Overlook. This region is one of the numerous areas in the Rocky Mountains where the WSR-88D network does not provide sufficient weather coverage due to blockages, and the limitations have impeded forecasters and local emergency managers from making accurate predictions and issuing weather warnings. High resolution observations were collected to document the precipitation characteristics and demonstrate the added values of deploying a small weather radar in such context. The analysis of the detailed vertical structure of precipitation explain the decreased signal sampled by the operational radars. The specific microphysics analyzed though polarimetry suggest that the operational Z-R relationships may not be appropriate to monitor severe weather over this wildfire affected region. Collaboration with the local emergency managers and the National Weather Service shows the critical value of deploying mobile, polarimetric and unmanned radars in complex terrain. Several selected cases are provided in this paper for illustration.

Introduction Wind farms in complex terrains: an introduction.

PubMed

Alfredsson, P H; Segalini, A

2017-04-13

Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas-locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

Assessing the Genetic Influence of Ancient Sociopolitical Structure: Micro-differentiation Patterns in the Population of Asturias (Northern Spain)

PubMed Central

Pardiñas, Antonio F.; Roca, Agustín; García-Vazquez, Eva; López, Belén

2012-01-01

The human populations of the Iberian Peninsula are the varied result of a complex mixture of cultures throughout history, and are separated by clear social, cultural, linguistic or geographic barriers. The stronger genetic differences between closely related populations occur in the northern third of Spain, a phenomenon commonly known as “micro-differentiation”. It has been argued and discussed how this form of genetic structuring can be related to both the rugged landscape and the ancient societies of Northern Iberia, but this is difficult to test in most regions due to the intense human mobility of previous centuries. Nevertheless, the Spanish autonomous community of Asturias shows a complex history which hints of a certain isolation of its population. This, joined together with a difficult terrain full of deep valleys and steep mountains, makes it suitable for performing a study of genetic structure, based on mitochondrial DNA and Y-Chromosome markers. Our analyses do not only show that there are micro-differentiation patterns inside the Asturian territory, but that these patterns are strikingly similar between both uniparental markers. The inference of barriers to gene flow also indicates that Asturian populations from the coastal north and the mountainous south seem to be relatively isolated from the rest of the territory. These findings are discussed in light of historic and geographic data and, coupled with previous evidence, show that the origin of the current genetic patterning might indeed lie in Roman and Pre-Roman sociopolitical divisions. PMID:23209673

Large eddy simulation modeling of particle-laden flows in complex terrain

NASA Astrophysics Data System (ADS)

Salesky, S.; Giometto, M. G.; Chamecki, M.; Lehning, M.; Parlange, M. B.

2017-12-01

The transport, deposition, and erosion of heavy particles over complex terrain in the atmospheric boundary layer is an important process for hydrology, air quality forecasting, biology, and geomorphology. However, in situ observations can be challenging in complex terrain due to spatial heterogeneity. Furthermore, there is a need to develop numerical tools that can accurately represent the physics of these multiphase flows over complex surfaces. We present a new numerical approach to accurately model the transport and deposition of heavy particles in complex terrain using large eddy simulation (LES). Particle transport is represented through solution of the advection-diffusion equation including terms that represent gravitational settling and inertia. The particle conservation equation is discretized in a cut-cell finite volume framework in order to accurately enforce mass conservation. Simulation results will be validated with experimental data, and numerical considerations required to enforce boundary conditions at the surface will be discussed. Applications will be presented in the context of snow deposition and transport, as well as urban dispersion.

Sustainable land cover and terrain modification to enhance convection and precipitation in the arid region of the United Arab Emirates

NASA Astrophysics Data System (ADS)

Wulfmeyer, V.; Branch, O.; Adebabseh, A.; Temimi, M.

2017-12-01

Irrigated plantations and modified terrain can provide a sustainable means of enhancing convective rainfall in arid regions like the United Arab Emirates, or UAE, and can be used to aid ongoing cloud seeding operations through the geographic-localization of seedable cloud formation. The first method, the planting of vast irrigated plantations of hardy desert shrubs, can lead to wind convergence and vertical mixing through increased roughness and modified radiative balances. When upper-air atmospheric instability is present, these phenomena can initiate convection. The second method, increasing the elevation of moderate-sized mountains, is based on the correlation between elevation and the number of summertime convection initiation events observed in the mountains of the UAE and Oman. This augmentation of existing orographic features should therefore increase the likelihood and geographic range of convection initiation events. High-resolution simulations provide a powerful means of assessing the likely impacts of land surface modifications. Previous convection-permitting simulations have yielded some evidential support for these hypotheses, but higher resolutions down to 1 km provide more detail regarding convective processes and land surface representation. Using seasonal simulations with the WRF-NOAHMP land-atmosphere model at a 2.5 km resolution, we identify frequent zones of convergence and atmospheric instability in the UAE and select interesting cases. Using these results, as well as an agricultural feasibility study, we identify optimal plantation positions within the UAE. We then run realistic plantation scenarios for single case studies at 1 km resolution. Using the same cases, we simulate the impact of augmenting mountain elevations on convective processes, with the augmentation being achieved through GIS-based modification of the terrain data. For both methods, we assess the impacts quantitatively and qualitatively, and assess key processes and dependencies. If we can demonstrate that convective rainfall would be enhanced through feasible agricultural and engineering methods, then land surface-based weather modification deserves serious consideration as a solution for water scarcity and anthropogenic climate change.

Galle Crater

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 19 June 2002) The Science This image is of part of Galle Crater, located at 51.9S, 29.5W. This image was taken far enough south and late enough into the southern hemisphere fall to catch observe water ice clouds partially obscuring the surface. The most striking aspect of the surface is the dissected layered unit to the left in the image. Other areas also appear to have layering, but they are either more obscured by clouds or are less well defined on the surface. The layers appear to be mostly flat lying and layer boundaries appear as topographic lines would on a map, but there are a few areas where it appears that these layers have been deformed to some level. Other areas of the image contain rugged, mountainous terrain as well as a separate pitted terrain where the surface appears to be a separate unit from the mountains and the layered terrain. The Story Galle Crater is officially named after a German astronomer who, in 1846, was the first to observe the planet Neptune. It is better known, however, as the 'Happy Face Crater.' The image above focuses on too small an area of the crater to see its beguiling grin, but you can catch the rocky line of a 'half-smile' in the context image to the right (to the left of the red box). While water ice clouds make some of the surface harder to see, nothing detracts from the fabulous layering at the center left-hand edge of the image. If you click on the above image, the scalloped layers almost look as if a giant knife has swirled through a landscape of cake frosting. These layers, the rugged, mountains near them, and pits on the surface (upper to middle section of the image on the right-hand side) all create varying textures on the crater floor. With such different features in the same place, geologists have a lot to study to figure out what has happened in the crater since it formed.

Delineation, characterization, and classification of topographic eminences

NASA Astrophysics Data System (ADS)

Sinha, Gaurav

Topographic eminences are defined as upwardly rising, convex shaped topographic landforms that are noticeably distinct in their immediate surroundings. As opposed to everyday objects, the properties of a topographic eminence are dependent not only on how it is conceptualized, but is also intrinsically related to its spatial extent and its relative location in the landscape. In this thesis, a system for automated detection, delineation and characterization of topographic eminences based on an analysis of digital elevation models is proposed. Research has shown that conceptualization of eminences (and other landforms) is linked to the cultural and linguistic backgrounds of people. However, the perception of stimuli from our physical environment is not subject to cultural or linguistic bias. Hence, perceptually salient morphological and spatial properties of the natural landscape can form the basis for generically applicable detection and delineation of topographic eminences. Six principles of cognitive eminence modeling are introduced to develop the philosophical foundation of this research regarding eminence delineation and characterization. The first step in delineating eminences is to automatically detect their presence within digital elevation models. This is achieved by the use of quantitative geomorphometric parameters (e.g., elevation, slope and curvature) and qualitative geomorphometric features (e.g., peaks, passes, pits, ridgelines, and valley lines). The process of eminence delineation follows that of eminence detection. It is posited that eminences may be perceived either as monolithic terrain objects, or as composites of morphological parts (e.g., top, bottom, slope). Individual eminences may also simultaneously be conceived as comprising larger, higher order eminence complexes (e.g., mountain ranges). Multiple algorithms are presented for the delineation of simple and complex eminences, and the morphological parts of eminences. The proposed eminence detection and delineation methods are amenable to intuitive parameterization such that they can easily capture the multitude of eminence conceptualizations that people develop due to differences in terrain type and cultural and linguistic backgrounds. Eminence delineation is an important step in object based modeling of the natural landscape. However, mere 'geocoding' of eminences is not sufficient for modeling how people intuitively perceive and reason about eminences. Therefore, a comprehensive eminence parameterization system for characterizing the perceptual properties of eminences is also proposed in this thesis. Over 40 parameters are suggested for measuring the commonly perceived properties of eminences: size, shape, topology, proximity, and visibility. The proposed parameters describe different aspects of naive eminence perception. Quantitative analysis of eminence parameters using cluster analysis, confirms that not only can eminences be parameterized as individual terrain objects, but that eminence (dis)similarities can be exploited to develop intuitive eminence classification systems. Eminence parameters are also shown to be essential for exploring the relationships between extracted eminences and natural language terms (e.g., hill, mount, mountain, peak) used commonly to refer to different types of eminences. The results from this research confirm that object based modeling of the landscape is not only useful for terrain information system design, but is also essential for understanding how people commonly conceptualize their observations of and interactions with the natural landscape.

An interdisciplinary swat ecohydrological model to define catchment-scale hydrologic partitioning

NASA Astrophysics Data System (ADS)

Shope, C. L.; Maharjan, G. R.; Tenhunen, J.; Seo, B.; Kim, K.; Riley, J.; Arnhold, S.; Koellner, T.; Ok, Y. S.; Peiffer, S.; Kim, B.; Park, J.-H.; Huwe, B.

2013-06-01

Land use and climate change have long been implicated in modifying ecosystem services, such as water quality and water yield, biodiversity, and agricultural production. To account for future effects on ecosystem services, the integration of physical, biological, economic, and social data over several scales must be implemented to assess the effects on natural resource availability and use. Our objective is to assess the capability of the SWAT model to capture short-duration monsoonal rainfall-runoff processes in complex mountainous terrain under rapid, event-driven processes in a monsoonal environment. To accomplish this, we developed a unique quality-control gap-filling algorithm for interpolation of high frequency meteorological data. We used a novel multi-location, multi-optimization calibration technique to improve estimations of catchment-wide hydrologic partitioning. We calibrated the interdisciplinary model to a combination of statistical, hydrologic, and plant growth metrics. In addition, we used multiple locations of different drainage area, aspect, elevation, and geologic substrata distributed throughout the catchment. Results indicate scale-dependent sensitivity of hydrologic partitioning and substantial influence of engineered features. While our model accurately reproduced observed discharge variability, the addition of hydrologic and plant growth objective functions identified the importance of culverts in catchment-wide flow distribution. The results of this study provide a valuable resource to describe landscape controls and their implication on discharge, sediment transport, and nutrient loading. This study also shows the challenges of applying the SWAT model to complex terrain and extreme environments. By incorporating anthropogenic features into modeling scenarios, we can greatly enhance our understanding of the hydroecological impacts on ecosystem services.

Spatial variability of shortwave radiative fluxes in the context of snowmelt

NASA Astrophysics Data System (ADS)

Pinker, Rachel T.; Ma, Yingtao; Hinkelman, Laura; Lundquist, Jessica

2014-05-01

Snow-covered mountain ranges are a major source of water supply for run-off and groundwater recharge. Snowmelt supplies as much as 75% of surface water in basins of the western United States. Factors that affect the rate of snow melt include incoming shortwave and longwave radiation, surface albedo, snow emissivity, snow surface temperature, sensible and latent heat fluxes, ground heat flux, and energy transferred to the snowpack from deposited snow or rain. The net radiation generally makes up about 80% of the energy balance and is dominated by the shortwave radiation. Complex terrain poses a great challenge for obtaining the needed information on radiative fluxes from satellites due to elevation issues, spatially-variable cloud cover, rapidly changing surface conditions during snow fall and snow melt, lack of high quality ground truth for evaluation of the satellite based estimates, as well as scale issues between the ground observations and the satellite footprint. In this study we utilize observations of high spatial resolution (5-km) as available from the Moderate Resolution Imaging Spectro-radiometer (MODIS) to derive surface shortwave radiative fluxes in complex terrain, with attention to the impact of slopes on the amount of radiation received. The methodology developed has been applied to several water years (January to July during 2003, 2004, 2005 and 2009) over the western part of the United States, and the available information was used to derive metrics on spatial and temporal variability in the shortwave fluxes. It is planned to apply the findings from this study for testing improvements in Snow Water Equivalent (SWE) estimates.

Landscape analysis of methane flux across complex terrain

NASA Astrophysics Data System (ADS)

Kaiser, K. E.; McGlynn, B. L.; Dore, J. E.

2014-12-01

Greenhouse gas (GHG) fluxes into and out of the soil are influenced by environmental conditions resulting in landscape-mediated patterns of spatial heterogeneity. The temporal variability of inputs (e.g. precipitation) and internal redistribution (e.g. groundwater flow) and dynamics (e.g. microbial communities) make predicating these fluxes challenging. Complex terrain can provide a laboratory for improving understanding of the spatial patterns, temporal dynamics, and drivers of trace gas flux rates, requisite to constraining current GHG budgets and future scenarios. Our research builds on previous carbon cycle research at the USFS Tenderfoot Creek Experimental Forest, Little Belt Mountains, Montana that highlighted the relationships between landscape position and seasonal CO2 efflux, induced by the topographic redistribution of water. Spatial patterns and landscape scale mediation of CH4 fluxes in seasonally aerobic soils have not yet been elucidated. We measured soil methane concentrations and fluxes across a full range of landscape positions, leveraging topographic and seasonal gradients, to examine the relationships between environmental variables, hydrologic dynamics, and CH4 production and consumption. We determined that a threshold of ~30% VWC distinguished the direction of flux at individual time points, with the riparian area and uplands having distinct source/sink characteristics respectively. Riparian locations were either strong sources or fluctuated between sink and source behavior, resulting in near neutral seasonal flux. Upland sites however, exhibited significant relationships between sink strength and topographic/energy balance indices. Our results highlight spatial and temporal coherence to landscape scale heterogeneity of CH4 dynamics that can improve estimates of landscape scale CH4 balances and sensitivity to change.

Validation of satellite daily rainfall estimates in complex terrain of Bali Island, Indonesia

NASA Astrophysics Data System (ADS)

Rahmawati, Novi; Lubczynski, Maciek W.

2017-11-01

Satellite rainfall products have different performances in different geographic regions under different physical and climatological conditions. In this study, the objective was to select the most reliable and accurate satellite rainfall products for specific, environmental conditions of Bali Island. The performances of four spatio-temporal satellite rainfall products, i.e., CMORPH25, CMORPH8, TRMM, and PERSIANN, were evaluated at the island, zonation (applying elevation and climatology as constraints), and pixel scales, using (i) descriptive statistics and (ii) categorical statistics, including bias decomposition. The results showed that all the satellite products had low accuracy because of spatial scale effect, daily resolution and the island complexity. That accuracy was relatively lower in (i) dry seasons and dry climatic zones than in wet seasons and wet climatic zones; (ii) pixels jointly covered by sea and mountainous land than in pixels covered by land or by sea only; and (iii) topographically diverse than uniform terrains. CMORPH25, CMORPH8, and TRMM underestimated and PERSIANN overestimated rainfall when comparing them to gauged rain. The CMORPH25 had relatively the best performance and the PERSIANN had the worst performance in the Bali Island. The CMORPH25 had the lowest statistical errors, the lowest miss, and the highest hit rainfall events; it also had the lowest miss rainfall bias and was relatively the most accurate in detecting, frequent in Bali, ≤ 20 mm day-1 rain events. Lastly, the CMORPH25 coarse grid better represented rainfall events from coastal to inlands areas than other satellite products, including finer grid CMORPH8.

Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000/UMTS System through Terrain Diffraction at S-Band

NASA Technical Reports Server (NTRS)

Ho, Christian M.; Sue, Miles K.; Peng, Ted K.; Smith, Ernest K.

2002-01-01

This study evaluates the possible interference from DSN Robledo 70-m transmitter with Madrid IMT-2000/UMTS wireless users in Spain as both systems will share the same frequency band. Using the effective earth radius, the 50 km terrain profile between Robledo and Madrid is modified and reconstructed. The diffraction propagation losses due to mountain peaks are calculated for the receivers in Madrid urban area. The mountains along the path are simplified into a rounded knife-edge and a rounded obstacle. The results show that for a near surface receiver (1.5 m above the ground) in Madrid, interference signal powers received are less than -135 dBm, which is far below the -109 dBm, the IMT-2000 wireless phone threshold. When a receiver is located at about 40 m above the ground (e.g., the top of Clock Tower of Cibeles Palace), diffraction will generate interference power less than -115 dBm. We find that our calculation results are basically consistent with those from the Longley-Rice model, while the latter has smaller loss because of the low resolution terrain profile used. As a comparison, we also find that the measurements of interference powers of -121.2 dBm at the top of Clock tower is in the range of the estimation. We conclude that the interference through the diffraction mechanism will not cause any problem to IMT-2000/UMTS users at near the surface of Madrid urban area.

Geology of Pluto and Charon Overview

NASA Technical Reports Server (NTRS)

Moore, Jeffrey Morgan

2015-01-01

Pluto's surface was found to be remarkably diverse in terms of its range of landforms, terrain ages, and inferred geological processes. There is a latitudinal zonation of albedo. The conspicuous bright albedo heart-shaped feature informally named Tombaugh Regio is comprised of several terrain types. Most striking is Texas-sized Sputnik Planum, which is apparently level, has no observable craters, and is divided by polygons and ovoids bounded by shallow troughs. Small smooth hills are seen in some of the polygon-bounding troughs. These hills could either be extruded or exposed by erosion. Sputnik Planum polygon/ovoid formation hypotheses range from convection to contraction, but convection is currently favored. There is evidence of flow of plains material around obstacles. Mountains, especially those seen south of Sputnik Planum, exhibit too much relief to be made of CH4, CO, or N2, and thus are probably composed of H2O-ice basement material. The north contact of Sputnik Planum abuts a scarp, above which is heavily modified cratered terrain. Pluto's large moon Charon is generally heavily to moderately cratered. There is a mysterious structure in the arctic. Charon's surface is crossed by an extensive system of rift faults and graben. Some regions are smoother and less cratered, reminiscent of lunar maria. On such a plain are large isolated block mountains surrounded by moats. At this conference we will present highlights of the latest observations and analysis. This work was supported by NASA's New Horizons project

Orographic Modification of Precipitation Processes in a Tropical Cyclone Moving over a Continental Mountain Range

NASA Astrophysics Data System (ADS)

DeHart, Jennifer C.

Airborne radar reflectivity data and numerical simulations are examined to determine how tropical cyclone precipitation processes are impacted by landfall over a continental mountain range. Analysis of the high-resolution radar data collected within Hurricane Karl (2010) during the Genesis and Rapid Intensification Processes (GRIP) shows that radar reflectivity enhancement in regions of upslope flow is constrained to low-levels. Reflectivity enhancement is not uniform and discrete regions of enhanced precipitation are embedded within a broad echo. In conjunction with an upstream dropsonde that exhibits weak instability, the radar data suggest a mix of gentle ascent and shallow convection occur. Regions of downslope flow are characterized by precipitation originating further aloft with little modification near low levels. Satellite data further indicate that deep convection develops after the high clouds dissipate, indicating that the evolving thermodynamic environment favors orographic modification processes beyond collection of orographically-generated cloud water. Numerical simulations examine how modification processes controlling precipitation are affected by the height of an idealized plateau. When terrain is minimal, the tropical cyclone decays slowly, the upper-level warm core remains robust, the moist neutral environment persists, and precipitation processes are largely concentrated within the eyewall and rainband. Movement over a tall topographic barrier induces rapid decay, which erodes the warm core and moist neutral environment. A mix of forced ascent and buoyant motions contribute to enhanced warm rain processes over the terrain. Overall, all microphysical quantities are greater for the tall plateau storm, but concentrations within the innermost core decay rapidly along with the storm. It is shown that the simulated tropical cyclone precipitation is heavily influenced by overestimated graupel production, which is a common problem of microphysical schemes. Surface precipitation is comparable between the two experiments, suggesting that strong decay of the storm affects the upper limit of precipitation. Similar precipitation patterns between the observations and tall plateau simulation suggest that the model obtains realistic precipitation through incorrect microphysical processes, but a lack of microphysical observations prevent full assessment of that hypothesis. Overall, this dissertation demonstrates that decay due to landfall over complex terrain affects the inner core thermodynamic and kinematic environment, which in turn affects the type and organization of precipitation processes that occur.

High resolution simulations of orographic flow over a complex terrain on the Southeast coast of Brazil

NASA Astrophysics Data System (ADS)

Chou, S. C.; Zolino, M. M.; Gomes, J. L.; Bustamante, J. F.; Lima-e-Silva, P. P.

2012-04-01

The Eta Model is used operationally by CPTEC to produce weather forecasts over South America since 1997. The model has gone through upgrades. In order to prepare the model for operational higher resolution forecasts, the model is configured and tested over a region of complex topography located near the coast of Southeast Brazil. The Eta Model was configured, with 2-km horizontal resolution and 50 layers. The Eta-2km is a second nesting, it is driven by Eta-15km, which in its turn is driven by Era-Interim reanalyses. The model domain includes the two Brazilians cities, Rio de Janeiro and Sao Paulo, urban areas, preserved tropical forest, pasture fields, and complex terrain and coastline. Mountains can rise up to about 700m. The region suffers frequent events of floods and landslides. The objective of this work is to evaluate high resolution simulations of wind and temperature in this complex area. Verification of model runs uses observations taken from the nuclear power plant. Accurate near-surface wind direction and magnitude are needed for the plant emergency plan and winds are highly sensitive to model spatial resolution and atmospheric stability. Verification of two cases during summer shows that model has clear diurnal cycle signal for wind in that region. The area is characterized by weak winds which makes the simulation more difficult. The simulated wind magnitude is about 1.5m/s, which is close to observations of about 2m/s; however, the observed change of wind direction of the sea breeze is fast whereas it is slow in the simulations. Nighttime katabatic flow is captured by the simulations. Comparison against Eta-5km runs show that the valley circulation is better described in the 2-km resolution run. Simulated temperatures follow closely the observed diurnal cycle. Experiments improving some surface conditions such as the surface temperature and land cover show simulation error reduction and improved diurnal cycle.

Modelling vertical error in LiDAR-derived digital elevation models

NASA Astrophysics Data System (ADS)

Aguilar, Fernando J.; Mills, Jon P.; Delgado, Jorge; Aguilar, Manuel A.; Negreiros, J. G.; Pérez, José L.

2010-01-01

A hybrid theoretical-empirical model has been developed for modelling the error in LiDAR-derived digital elevation models (DEMs) of non-open terrain. The theoretical component seeks to model the propagation of the sample data error (SDE), i.e. the error from light detection and ranging (LiDAR) data capture of ground sampled points in open terrain, towards interpolated points. The interpolation methods used for infilling gaps may produce a non-negligible error that is referred to as gridding error. In this case, interpolation is performed using an inverse distance weighting (IDW) method with the local support of the five closest neighbours, although it would be possible to utilize other interpolation methods. The empirical component refers to what is known as "information loss". This is the error purely due to modelling the continuous terrain surface from only a discrete number of points plus the error arising from the interpolation process. The SDE must be previously calculated from a suitable number of check points located in open terrain and assumes that the LiDAR point density was sufficiently high to neglect the gridding error. For model calibration, data for 29 study sites, 200×200 m in size, belonging to different areas around Almeria province, south-east Spain, were acquired by means of stereo photogrammetric methods. The developed methodology was validated against two different LiDAR datasets. The first dataset used was an Ordnance Survey (OS) LiDAR survey carried out over a region of Bristol in the UK. The second dataset was an area located at Gador mountain range, south of Almería province, Spain. Both terrain slope and sampling density were incorporated in the empirical component through the calibration phase, resulting in a very good agreement between predicted and observed data (R2 = 0.9856 ; p < 0.001). In validation, Bristol observed vertical errors, corresponding to different LiDAR point densities, offered a reasonably good fit to the predicted errors. Even better results were achieved in the more rugged morphology of the Gador mountain range dataset. The findings presented in this article could be used as a guide for the selection of appropriate operational parameters (essentially point density in order to optimize survey cost), in projects related to LiDAR survey in non-open terrain, for instance those projects dealing with forestry applications.

[Applications of 2D and 3D landscape pattern indices in landscape pattern analysis of mountainous area at county level].

PubMed

Lu, Chao; Qi, Wei; Li, Le; Sun, Yao; Qin, Tian-Tian; Wang, Na-Na

2012-05-01

Landscape pattern indices are the commonly used tools for the quantitative analysis of landscape pattern. However, the traditional 2D landscape pattern indices neglect the effects of terrain on landscape, existing definite limitations in quantitatively describing the landscape patterns in mountains areas. Taking the Qixia City, a typical mountainous and hilly region in Shandong Province of East China, as a case, this paper compared the differences between 2D and 3D landscape pattern indices in quantitatively describing the landscape patterns and their dynamic changes in mountainous areas. On the basis of terrain structure analysis, a set of landscape pattern indices were selected, including area and density (class area and mean patch size), edge and shape (edge density, landscape shape index, and fractal dimension of mean patch), diversity (Shannon's diversity index and evenness index) , and gathering and spread (contagion index). There existed obvious differences between the 3D class area, mean patch area, and edge density and the corresponding 2D indices, but no significant differences between the 3D landscape shape index, fractal dimension of mean patch, and Shannon' s diversity index and evenness index and the corresponding 2D indices. The 3D contagion index and 2D contagion index had no difference. Because the 3D landscape pattern indices were calculated by using patch surface area and surface perimeter whereas the 2D landscape pattern indices were calculated by adopting patch projective area and projective perimeter, the 3D landscape pattern indices could be relative accurate and efficient in describing the landscape area, density and borderline, in mountainous areas. However, there were no distinct differences in describing landscape shape, diversity, and gathering and spread between the 3D and 2D landscape pattern indices. Generally, by introducing 3D landscape pattern indices to topographic pattern, the description of landscape pattern and its dynamic change would be relatively accurate.

A bioclimatic characterization of high elevation habitats in the Alborz mountains of Iran.

PubMed

Noroozi, Jalil; Körner, Christian

2018-01-01

The Alborz mountains in N-Iran at 36° N rise from the Caspian Sea to 5671 m a.s.l., with warm-temperate, winter-deciduous forests in the lower montane belt in northern slopes, and vast treeless terrain at higher elevation. A lack of rainfall (ca. 550 mm at high elevations) cannot explain the absence of trees. Hence, it is an open question, which parts of these mountains belong to the alpine belt. Here we use bioclimatic data to estimate the position of the potential climatic treeline, and thus, define bioclimatologically, what is alpine and what is not. We employed the same miniature data loggers and protocol that had been applied in a Europe-wide assessment of alpine climates and a global survey of treeline temperatures. The data suggest a potential treeline position at ca. 3300 m a.s.l., that is ca. 900 m above the upper edge of the current oak forest, or 450 m above its highest outposts. The alpine terrain above the climatic treeline position shows a temperature regime comparable to sites in the European Alps. At the upper limit of angiosperm life, at 4850 m a.s.l., the growing season lasted 63 days with a seasonal mean root zone temperature of 4.5 °C. We conclude that (1) the absence of trees below 2850 m a.s.l. is clearly due to millennia of land use. The absence of trees between 2850 and 3300 m a.s.l. is either due to the absence of suitable tree taxa, or the only potential regional taxon for those elevations, Juniperus excelsa , had been eradicated by land use as well. (2) These continental mountains provide thermal life conditions in the alpine belt similar to other temperate mountains. (3) Topography and snow melt regimes play a significant role for the structure of the alpine vegetation mosaics.

Regulation of Post-Logging N Turnover and Mobile N by Solar Insolation in a Steep Rocky Mountain Watershed

NASA Astrophysics Data System (ADS)

Stewart, D. M.; Silins, U.; Emelko, M.; Stone, M.

2016-12-01

While forest harvesting effects on nitrogen (N) cycling and watershed nitrogen export are generally well documented, the factors that govern variation in post-disturbance watershed export of N after forest disturbance across different hydro-climatic regions as less well understood. Factors that regulate the coupling of N dynamics on hillslopes with receiving streams are not well understood in steeper mountainous terrain where strong spatial variation in radiation, temperature, and nutrient turnover potentially govern post-disturbance catchment exports of N. Objectives of this study were to explore the relative influence of variation in hillslope position (upper vs lower) and radiation load among contrasting south- and north-facing hillslope positions in regulating soil nitrogen turnover and mobile nitrogen (NO-3) after clear-cut logging in the Rocky Mountains of south-west Alberta, Canada. A combined approach employing replicated measurement of key soil N species in soil solution (available N, using ion exchange membranes) and shallow hillslope pore water N (using suction lysimeters) was used to explore how variation in hillslope position and radiation load (S/N facing) after clear-cut logging of a Lodgepole pine dominated Rocky Mountain watershed in southwest Alberta. These were compared to parallel measurements in unharvested (reference) hillslopes in the same watershed. Logging was completed in 2015 with measurements of soil and shallow groundwater N at 6 week intervals from April to Oct. 2016. Compared to other types of forest disturbance (i.e. wildfire) common in this region, clear-cut harvesting did not produce a large impact on both surface and deeper available N for reference and harvested stands. In particular, early season available NO-3 is enriched in upper stands, while other factors showed less of an effect. Overall, results provide important insights into how disturbance effects on mobile N among hillslopes of contrasting energy gain, soil moisture, and thermal regimes interact in driving post-disturbance N export in steep, mountainous terrain.

Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal--A Systematic Synthesis of Literature.

PubMed

Dhimal, Meghnath; Ahrens, Bodo; Kuch, Ulrich

2015-01-01

Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change. A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December 2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines. We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies. Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant.

Nonturbulent dispersion processes in complex terrain

Treesearch

Michael A. Fosberg; Douglas G. Fox; E.A. Howard; Jack D. Cohen

1976-01-01

Mass divergence influences on plume dispersion modify classic Gaussian calculations by as much as a factor of two in complex terrain. The Gaussian plume was derived in flux form to include this process.Authors' response to comments and criticism received following this publication:

Wasatch and Uinta Mountains Ecoregion: Chapter 9 in Status and trends of land change in the Western United States--1973 to 2000

USGS Publications Warehouse

Brooks, Mark S.

2012-01-01

The Wasatch and Uinta Mountains Ecoregion covers approximately 44,176 km2 (17, 057 mi2) (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). With the exception of a small part of the ecoregion extending into southern Wyoming and southern Idaho, the vast majority of the ecoregion is located along the eastern mountain ranges of Utah. The ecoregion is situated between the Wyoming Basin and Colorado Plateaus Ecoregions to the east and south and the Central Basin and Range Ecoregion to the west; in addition, the Middle Rockies, Snake River Basin, and Northern Basin and Range Ecoregions are nearby to the north. Considered the western front of the Rocky Mountains, the two major mountain ranges that define the Wasatch and Uinta Mountains Ecoregion include the north-south-trending Wasatch Range and east-west- trending Uinta Mountains. Both mountain ranges have been altered by multiple mountain building and burial cycles since the Precambrian era 2.6 billion years ago, and they have been shaped by glacial processes as early as 1.6 million years ago. The terrain is defined by sharp ridgelines, glacial lakes, and narrow canyons, with elevations ranging from 1,829 m in the lower canyons to 4,123 m at Kings Peak, the highest point in Utah (Milligan, 2010).

New Insight into the Role of Tectonics versus Gravitational Deformation in Development of Surface Ruptures along the Ragged Mountain Fault, Katalla, Alaska USA: Applications of High-Resolution Three-Dimensional Terrain Models

NASA Astrophysics Data System (ADS)

Heinlein, S. N.; Pavlis, T. L.; Bruhn, R. L.; McCalpin, J. P.

2017-12-01

This study evaluates a surface structure using 3D visualization of LiDAR and aerial photography then analyzes these datasets using structure mapping techniques. Results provide new insight into the role of tectonics versus gravitational deformation. The study area is located in southern Alaska in the western edge of the St. Elias Orogen where the Yakutat microplate is colliding into Alaska. Computer applications were used to produce 3D terrain models to create a kinematic assessment of the Ragged Mountain fault which trends along the length of the east flank of Ragged Mountain. The area contains geomorphic and structural features which are utilize to determine the type of displacement on the fault. Previous studies described the Ragged Mountain fault as a very shallow (8°), west-dipping thrust fault that reactivated in the Late Holocene by westward-directed gravity sliding and inferred at least 180 m of normal slip, in a direction opposite to the (relative) eastward thrust transport of the structure inferred from stratigraphic juxtaposition. More recently this gravity sliding hypothesis has been questioned and this study evaluates one of these alternative hypotheses; that uphill facing normal fault-scarps along the Ragged Mountain fault trace represent extension above a buried ramp in a thrust and is evaluated with a fault-parallel flow model of hanging-wall folding and extension. Profiles across the scarp trace were used to illustrate the curvature of the topographic surfaces adjacent to the scarps system and evaluate their origin. This simple kinematic model tests the hypothesis that extensional fault scarps at the surface are produced by flexure above a deeper ramp in a largely blind thrust system. The data in the context of this model implies that the extensional scarp structures previously examined represent a combination of erosionally modified features overprinted by flexural extension above a thrust system. Analyses of scarp heights along the structure are combined with the model to suggest a decrease in Holocene slip from south to north along the Ragged Mountain fault from 11.3 m to 0.2 m, respectively.

High Tech in Small Places

ERIC Educational Resources Information Center

Shah, Nirvi

2010-01-01

Across a giant swath of desert and mountain terrain southeast of Tucson, one yellow school bus has been carrying an extra passenger since last fall. Along with dozens of students, the bus rolls through the Vail School District's most far-flung portions equipped with a wireless router. It delivers the Internet to students for as many as three hours…

Terrain and vegetation structural influences on local avian species richness in two mixed-conifer forests

Treesearch

Jody C. Vogeler; Andrew T. Hudak; Lee A. Vierling; Jeffrey Evans; Patricia Green; Kerri T. Vierling

2014-01-01

Using remotely-sensed metrics to identify regions containing high animal diversity and/or specific animal species or guilds can help prioritize forest management and conservation objectives across actively managed landscapes. We predicted avian species richness in two mixed conifer forests, Moscow Mountain and Slate Creek, containing different management contexts and...

Radio telemetry methods for studying spotted owls in the Pacific Northwest.

Treesearch

J.H. Guetterman; J.A. Burns; J.A. Reid; R.B. Horn; C.C. Foster

1991-01-01

The paper is a practical guide to field methodology for conducting a radio telemetry study of spotted owls (Strix occidentalis) in mountainous terrain. It begins with a synopsis of spotted owl biology and basic telemetry. The criteria used to select which owls will carry transmitters are discussed as are location and capture methods. Instructions...

Alternative Fuels Data Center: Alternative Fuel Vehicles Beat the Heat,

Science.gov Websites

standard for biodiesel, American Society for Testing Materials (ASTM) D675 fuel. "E85 is widely maintenance, Roaring Fork Transit Authority, Aspen, Colorado When thinking about buying an alternative fuel Gas Vehicles in Subzero Temps Up in the high terrain of the Colorado mountains, the Roaring Fork

Climate change in the Hawaiian Islands

Treesearch

Christian Giardina; Frank Hays; Jim Jacobi; Randall Kosaki; Loyal Mehrhoff; Stephen Miller

2008-01-01

In Hawai‘i, the seasonal and geographic distribution of rainfall and temperature has combined with steep, mountainous terrain to produce a wide array of island-scale climate regimes. These varying regimes in turn have supported the diversification of Hawai‘i native plants and animals. Increasing amounts of anthropogenic greenhouse gases will likely alter the...

Cable logging production rate equations for thinning young-growth Douglas-fir

Treesearch

Chris B. LeDoux; Lawson W. Starnes

1986-01-01

A cable logging thinning simulation model and field study data from cable thinning production studies have been assembled and converted into a set of simple equations. These equations can be used to estimate the hourly production rates of various cable thinning machines operating in the mountainous terrain of western Oregon and western Washington. The equations include...

49 CFR 350.309 - What activities are eligible for reimbursement under the MCSAP?

Code of Federal Regulations, 2010 CFR

2010-10-01

... a level at least equal to the average level of such activities conducted in the State in fiscal...: (a) The five national program elements listed in § 350.109 of this part. (b) Sanitary food... steep grades or mountainous terrains where the weight of a CMV can significantly affect the safe...

Fires and forest succession in the Bitterroot Mountains of northern Idaho

Treesearch

J. A. Larsen

1929-01-01

Foresters have recently begun to seek a more intimate knowledge of the natural, successional stages by which forests regain terrain lost by extensive fires or other pronounced denuding agencies. Studies in this field lead to a closer understanding of the factors which control the distribution, composition and density of the present forest, the silvical requirements of...

Simplified methods for evaluating road prism stability

Treesearch

William J. Elliot; Mark Ballerini; David Hall

2003-01-01

Mass failure is one of the most common failures of low-volume roads in mountainous terrain. Current methods for evaluating stability of these roads require a geotechnical specialist. A stability analysis program, XSTABL, was used to estimate the stability of 3,696 combinations of road geometry, soil, and groundwater conditions. A sensitivity analysis was carried out to...

Techniques for the wheeled-skidder operator

Treesearch

Robert L. Hartman; Harry G. Gibson; Harry G. Gibson

1970-01-01

How much production a logger gets from a logging job may depend heavily on his skidder operators. They are key men on any logging job. This is one conclusion that forestry engineers at the USDA Forest Service's Forestry Sciences Laboratory at Morgantown, West Virginia, came to after studying the operation of u-heeled skidders in mountainous Appalachian terrain....

Numerical and Experimental Methods for Wake Flow Analysis in Complex Terrain

NASA Astrophysics Data System (ADS)

Castellani, Francesco; Astolfi, Davide; Piccioni, Emanuele; Terzi, Ludovico

2015-06-01

Assessment and interpretation of the quality of wind farms power output is a non-trivial task, which poses at least three main challenges: reliable comprehension of free wind flow, which is stretched to the limit on very complex terrains, realistic model of how wake interactions resemble on the wind flow, awareness of the consequences on turbine control systems, including alignment patterns to the wind and, consequently, power output. The present work deals with an onshore wind farm in southern Italy, which has been a test case of IEA- Task 31 Wakebench project: 17 turbines, with 2.3 MW of rated power each, are sited on a very complex terrain. A cluster of machines is investigated through numerical and experimental methods: CFD is employed for simulating wind fields and power extraction, as well as wakes, are estimated through the Actuator Disc model. SCADA data mining techniques are employed for comparison between models and actual performances. The simulations are performed both on the real terrain and on flat terrain, in order to disentangle the effects of complex flow and wake effects. Attention is devoted to comparison between actual alignment patterns of the cluster of turbines and predicted flow deviation.

Chaotic Mountain Blocks in Pluto’s Sputnik Planitia

NASA Astrophysics Data System (ADS)

Singer, Kelsi N.; Knight, Katherine I.; Stern, S. Alan; Olkin, Catherine; Grundy, William M.; McKinnon, William B.; Moore, Jeffrey M.; Schenk, Paul M.; Spencer, John R.; Weaver, Harold A.; Young, Leslie; Ennico, Kimberly; New Horizons Geology, Geophysics and Imaging Science Theme Team, The New Horizons Surface Composition Science Theme Team

2017-10-01

One of the first high-resolution Pluto images returned by New Horizons displayed a collection of tall, jagged peaks rising out of the large nitrogen ice sheet informally known as Sputnik Planitia (SP). This mountain range was later revealed to be one of several along the western edge of SP. The mountains are several hundred broken-up blocks of Pluto’s primarily water ice lithosphere and some retain surface terrains similar to the nearby intact crust surrounding SP. Water ice with some fractures or porosity is likely >5% less dense than solid N2 ice at Pluto’s temperatures. Thus it is possible the blocks are, or were, floating icebergs or at least partially suspended to the point that some blocks appear to be tilted as if they have faltered (Moore et al., 2016, Science, 351, 1284-1293).We analyze four mountain ranges on the western edge of SP and compare to chaotic terrains on Europa and Mars. The blocks on Pluto have angular planforms but we characterize their size using block surface area converted to an equivalent circular diameter. Topography was used to define block extents. The blocks range in size from 3-30 km in diameter, with a mode of ~8-10 km. Blocks range from 0.2-3.8 km in height, and block height generally increases with block diameter. One or more dark layers can be identified in a few scarp faces, and are at a similar depth to each other and to layers seen in fault and crater walls elsewhere on Pluto. A large N-S trending fault system runs tangential to SP and may be the source of crustal disruption on the western side.On Europa and Mars block sizes vary greatly between different chaos regions, but Conamara Chaos has an average block size of ~5 km in diameter, smaller than that typically seen on Pluto. Also the blocks often transition into fractured terrain still connected to the surround lithosphere at the periphery of the chaos regions. The source regions for the blocks are more obvious on Europa and Mars. Additionally the block heights on Europa and Mars generally do not increase with block size. Thus, the main mechanism of crustal breakup is likely different between these bodies.

Enhanced Orographic Tropical Rainfall: An Study of the Colombia's rainfall

NASA Astrophysics Data System (ADS)

Peñaranda, V. M.; Hoyos Ortiz, C. D.; Mesa, O. J.

2015-12-01

Convection in tropical regions may be enhanced by orographic barriers. The orographic enhancement is an intensification of rain rates caused by the forced lifting of air over a mountainous structure. Orographic heavy rainfall events, occasionally, comes along by flooding, debris flow and substantial amount of looses, either economics or human lives. Most of the heavy convective rainfall events, occurred in Colombia, have left a lot of victims and material damages by flash flooding. An urgent action is required by either scientific communities or society, helping to find preventive solutions against these kind of events. Various scientific literature reports address the feedback process between the convection and the local orographic structures. The orographic enhancement could arise by several physical mechanism: precipitation transport on leeward side, convection triggered by the forcing of air over topography, the seeder-feeder mechanism, among others. The identification of the physical mechanisms for orographic enhancement of rainfall has not been studied over Colombia. As far as we know, orographic convective tropical rainfall is just the main factor for the altitudinal belt of maximum precipitation, but the lack of detailed hydro-meteorological measurements have precluded a complete understanding of the tropical rainfall in Colombia and its complex terrain. The emergence of the multifractal theory for rainfall has opened a field of research which builds a framework for parsimonious modeling of physical process. Studies about the scaling behavior of orographic rainfall have found some modulating functions between the rainfall intensity probability distribution and the terrain elevation. The overall objective is to advance in the understanding of the orographic influence over the Colombian tropical rainfall based on observations and scaling-analysis techniques. We use rainfall maps, weather radars scans and ground-based rainfall data. The research strategy is the analysis of rainfall fields via first-order statistical properties, scaling functions, structure functions and spectral analysis, taking into account cloud-motion directions over mountainous slopes (windward/leeward side) and timing of the diurnal cycle. The analysis is developed for some Colombia's locations.

Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundquist, K A

Mesoscale models, such as the Weather Research and Forecasting (WRF) model, are increasingly used for high resolution simulations, particularly in complex terrain, but errors associated with terrain-following coordinates degrade the accuracy of the solution. Use of an alternative Cartesian gridding technique, known as an immersed boundary method (IBM), alleviates coordinate transformation errors and eliminates restrictions on terrain slope which currently limit mesoscale models to slowly varying terrain. In this dissertation, an immersed boundary method is developed for use in numerical weather prediction. Use of the method facilitates explicit resolution of complex terrain, even urban terrain, in the WRF mesoscale model.more » First, the errors that arise in the WRF model when complex terrain is present are presented. This is accomplished using a scalar advection test case, and comparing the numerical solution to the analytical solution. Results are presented for different orders of advection schemes, grid resolutions and aspect ratios, as well as various degrees of terrain slope. For comparison, results from the same simulation are presented using the IBM. Both two-dimensional and three-dimensional immersed boundary methods are then described, along with details that are specific to the implementation of IBM in the WRF code. Our IBM is capable of imposing both Dirichlet and Neumann boundary conditions. Additionally, a method for coupling atmospheric physics parameterizations at the immersed boundary is presented, making IB methods much more functional in the context of numerical weather prediction models. The two-dimensional IB method is verified through comparisons of solutions for gentle terrain slopes when using IBM and terrain-following grids. The canonical case of flow over a Witch of Agnesi hill provides validation of the basic no-slip and zero gradient boundary conditions. Specified diurnal heating in a valley, producing anabatic winds, is used to validate the use of flux (non-zero) boundary conditions. This anabatic flow set-up is further coupled to atmospheric physics parameterizations, which calculate surface fluxes, demonstrating that the IBM can be coupled to various land-surface parameterizations in atmospheric models. Additionally, the IB method is extended to three dimensions, using both trilinear and inverse distance weighted interpolations. Results are presented for geostrophic flow over a three-dimensional hill. It is found that while the IB method using trilinear interpolation works well for simple three-dimensional geometries, a more flexible and robust method is needed for extremely complex geometries, as found in three-dimensional urban environments. A second, more flexible, immersed boundary method is devised using inverse distance weighting, and results are compared to the first IBM approach. Additionally, the functionality to nest a domain with resolved complex geometry inside of a parent domain without resolved complex geometry is described. The new IBM approach is used to model urban terrain from Oklahoma City in a one-way nested configuration, where lateral boundary conditions are provided by the parent domain. Finally, the IB method is extended to include wall model parameterizations for rough surfaces. Two possible implementations are presented, one which uses the log law to reconstruct velocities exterior to the solid domain, and one which reconstructs shear stress at the immersed boundary, rather than velocity. These methods are tested on the three-dimensional canonical case of neutral atmospheric boundary layer flow over flat terrain.« less

Precipitation Processes and their Modulation by Synoptic Conditions and Complex Terrain Observed during the GPM Ground Validation Olympic Mountains Experiment (OLYMPEX)

NASA Astrophysics Data System (ADS)

McMurdie, L. A.; Houze, R.; Zagrodnik, J.; Rowe, A.; DeHart, J.; Barnes, H.

2016-12-01

Successful and sustainable coupling of human societies and natural systems requires effective governance, which depends on the existence of proper infrastructure (both hard and soft). In recent decades, much attention has been paid to what has allowed many small-scale self-organized coupled natural-human systems around the world to persist for centuries, thanks to a large part to the work by Elinor Ostrom and colleagues. In this work, we mathematically operationalize a conceptual framework that is developed based on this body of work by way of a stylized model. The model captures the interplay between replicator dynamics within the population, dynamics of natural resources, and threshold characteristics of public infrastructure. The model analysis reveals conditions for long-term sustainability and collapse of the coupled systems as well as other tradeoffs and potential pitfalls in governing these systems.

Vertical Transport of Aerosol Particles across Mountain Topography near the Los Angeles Basin

NASA Astrophysics Data System (ADS)

Murray, J. J.; Schill, S.; Freeman, S.; Bertram, T. H.; Lefer, B. L.

2015-12-01

Transport of aerosol particles is known to affect air quality and is largely dependent on the characteristic topography of the surrounding region. To characterize this transport, aerosol number distributions were collected with an Ultra-High Sensitivity Aerosol Spectrometer (UHSAS, DMT) during the 2015 NASA Student Airborne Research Program (SARP) in and around the Los Angeles Basin in Southern California. Increases in particle number concentration and size were observed over mountainous terrain north of Los Angeles County. Chemical analysis and meteorological lagrangian trajectories suggest orographic lifting processes, known as the "chimney effect". Implications for spatial transport and distribution will be discussed.

Airflows and turbulent flux measurements in mountainous terrain: Part 2: Mesoscale effects

USGS Publications Warehouse

Turnipseed, A.A.; Anderson, D.E.; Burns, S.; Blanken, P.D.; Monson, Russell K.

2004-01-01

The location of the Niwot Ridge Ameriflux site within the rocky mountains subjects it to airflows which are common in mountainous terrain. In this study, we examine the effects of some of these mesoscale features on local turbulent flux measurements; most notably, the formation of valley/mountain flows and mountain lee-side waves. The valley/mountain flows created local non-stationarities in the wind flow caused by the passage of a lee-side convergence zone (LCZ) in which upslope and downslope flows met in the vicinity of the measurement tower. During June-August, 2001, possible lee-side convergences were flagged for ???26% of all half-hour daytime flux measurement periods. However, there was no apparent loss of flux during these periods. On some relatively stable, summer nights, turbulence (designated via ??w), and scalar fluctuations (temperature and CO2, for example) exhibited periodicities that appeared congruent with passage of low frequency gravity waves (?? ??? 20 min). Spectral peaks at 0.0008 Hz (20 min) in both vertical velocity and scalar spectra were observed and indicated that 25-50% of the total scalar covariances were accounted for by the low frequency waves. During some periods of strong westerly winds (predominantly in winter), large mountain gravity waves were observed to form. Typically, the flux tower resided within a region of downslope "shooting flow", which created high turbulence, but had no detrimental effect on local flux measurements based on valid turbulence statistics and nearly complete energy budget closure. Periodically, we found evidence for re-circulating, rotor winds in the simultaneous time series of wind data from the Ameriflux tower site and a second meteorological site situated 8 km upslope and to the West. Only 14% of the half-hour time periods that we examined for a 4 month period in the winter of 2000-2001 indicated the possible existence of rotor winds. On average, energy budget closure was ???20% less during periods with rotor occurrence compared to those without. Results from this study demonstrate that the potential exists for relatively rare, yet significant influences of mesoscale wind flow patterns on the local half-hour flux measurements at this site. Occurrence of these events could be detected through examination of normal turbulence statistical parameters. ?? 2004 Elsevier B.V. All rights reserved.

Near-Surface Wind Predictions in Complex Terrain with a CFD Approach Optimized for Atmospheric Boundary Layer Flows

NASA Astrophysics Data System (ADS)

Wagenbrenner, N. S.; Forthofer, J.; Butler, B.; Shannon, K.

2014-12-01

Near-surface wind predictions are important for a number of applications, including transport and dispersion, wind energy forecasting, and wildfire behavior. Researchers and forecasters would benefit from a wind model that could be readily applied to complex terrain for use in these various disciplines. Unfortunately, near-surface winds in complex terrain are not handled well by traditional modeling approaches. Numerical weather prediction models employ coarse horizontal resolutions which do not adequately resolve sub-grid terrain features important to the surface flow. Computational fluid dynamics (CFD) models are increasingly being applied to simulate atmospheric boundary layer (ABL) flows, especially in wind energy applications; however, the standard functionality provided in commercial CFD models is not suitable for ABL flows. Appropriate CFD modeling in the ABL requires modification of empirically-derived wall function parameters and boundary conditions to avoid erroneous streamwise gradients due to inconsistences between inlet profiles and specified boundary conditions. This work presents a new version of a near-surface wind model for complex terrain called WindNinja. The new version of WindNinja offers two options for flow simulations: 1) the native, fast-running mass-consistent method available in previous model versions and 2) a CFD approach based on the OpenFOAM modeling framework and optimized for ABL flows. The model is described and evaluations of predictions with surface wind data collected from two recent field campaigns in complex terrain are presented. A comparison of predictions from the native mass-consistent method and the new CFD method is also provided.

Arizona/New Mexico Mountains Ecoregion: Chapter 10 in Status and trends of land change in the Western United States--1973 to 2000

USGS Publications Warehouse

Ruhlman, Jana; Gass, Leila; Middleton, Barry

2012-01-01

As the name suggests, the Arizona/New Mexico Mountains Ecoregion includes much of the mountainous regions of these two states, plus a very small part in the Guadalupe Mountains of northwestern Texas. Several isolated areas of higher terrain in Arizona and New Mexico are also included in the ecoregion, which occupies approximately 108,432 km2 (41,866 mi2) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is bounded on the south by the Sonoran Basin and Range, Madrean Archipelago, and Chihuahuan Deserts Ecoregions; to the north, the ecoregion is both bounded and surrounded by the Arizona/New Mexico Plateau Ecoregion (fig. 1). The ecoregion encompasses the largest contiguous ponderosa pine (Pinus ponderosa) forest in the United States (Strom and Fulé, 2007), which stretches from Williams, Arizona, along the Mogollon Rim, Arizona, into southwestern New Mexico, north and west of Silver City, New Mexico.

Mapping snow avalanche risk using GIS technique and 3D modeling in Ceahlau Mountain

NASA Astrophysics Data System (ADS)

Covasnianu, A.; Grigoras, I. R.; State, L. E.; Balin, D.; Hogas, S.; Balin, I.

2009-04-01

This study consisted in a precise mapping project (GPS field campaign and on-screen digitization of the topographic maps at 1:5.000 scale) of the Ceahlau mountain area in Romanian Carpathians in order to address the snow avalanche risk management, surveying and monitoring. Thus we considered the slope, aspect, altitude, landforms and roughness derived from a high resolute numerical terrain model (31 km2 at 1: 5.000 scale resulted in a spatial resolution of 3 m by the help of Topo to Raster tool). These parameters were classified according to a model applied into Tatra Mountains and used over Ceahlau Massive. The results were adapted and interpreted considering to the European Avalanche Hazard Scale. This work was made in the context of the elaboration of Risk Map and is directly concerning both the security of tourism activities but also the management of the Natural Park Ceahlau. The extension of this method to similar mountain areas is ongoing.

Data gathering and simulation of climate change impacts in mountainous areas

NASA Astrophysics Data System (ADS)

Bachelet, D.; Baker, B.; Hicke, J.; Conklin, D.; McKelvey, K.

2007-12-01

High mountains include species most at risk in a warming environment and are a critical link in the water supply chain for both human and natural systems. Scientists are monitoring and simulating these systems as snowpack depth changes, snowmelt timing changes, frozen soils melt and destabilize, and low elevation populations migrate upslope. Natural climate cycles and human activities interact with climate change trends and complicate the interpretation of the signal we observe. For ex. over the past 4 years in Yunnan (China), we documented that herbaceous alpine meadows are contracting as forest tree line advances and alpine shrub biomass increases. This is a result of interactions between human land use alteration and observed shifts in climate. In North America as snowpack decreases, wolverines and lynx denning conditions are jeopardized as human pressure reduces their extent. Coarse scale vegetation shift models using downscaled future climate scenarios fail to capture complex terrain features and microclimatic conditions that can either ensure critical habitat for the in-situ survival of threatened species or make things worse (ex. rockfalls) for climate migrants. Recent simulation efforts focus on high resolution models that address aspect, slope, soil types, and microclimate variations that affect local and migrating plants, their associated pollinators and insect herbivores, modifying habitat availability for birds and mammals

Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA

USGS Publications Warehouse

Jenkins, S.E.; Hull, Sieg C.; Anderson, D.E.; Kaufman, D.S.; Pearthree, P.A.

2011-01-01

Long-term fire history reconstructions enhance our understanding of fire behaviour and associated geomorphic hazards in forested ecosystems. We used 14C ages on charcoal from fire-induced debris-flow deposits to date prehistoric fires on Kendrick Mountain, northern Arizona, USA. Fire-related debris-flow sedimentation dominates Holocene fan deposition in the study area. Radiocarbon ages indicate that stand-replacing fire has been an important phenomenon in late Holocene ponderosa pine (Pinus ponderosa) and ponderosa pine-mixed conifer forests on steep slopes. Fires have occurred on centennial scales during this period, although temporal hiatuses between recorded fires vary widely and appear to have decreased during the past 2000 years. Steep slopes and complex terrain may be responsible for localised crown fire behaviour through preheating by vertical fuel arrangement and accumulation of excessive fuels. Holocene wildfire-induced debris flow events occurred without a clear relationship to regional climatic shifts (decadal to millennial), suggesting that interannual moisture variability may determine fire year. Fire-debris flow sequences are recorded when (1) sufficient time has passed (centuries) to accumulate fuels; and (2) stored sediment is available to support debris flows. The frequency of reconstructed debris flows should be considered a minimum for severe events in the study area, as fuel production may outpace sediment storage. ?? IAWF 2011.

Landscape Heterogeneity mapping for Access to Tribal health care in Nilgiris District of Tamil Nadu, India

NASA Astrophysics Data System (ADS)

Brindha, B.; Prashanthi Devi, M.

2014-11-01

The Nilgiris district in Tamilnadu has a rich biodiversity in terms of flora, fauna and ethnic population. The district is basically a mountainous region, situated at an elevation of 2000 to 2,600 meters above MSL and constituting of several hill and Steep Mountain valleys. This region houses six tribes who are mainly forest dwellers and live in close settlements depending on the forest resources for their livelihood. The Tribes of Nilgiris have been diagnosed and monitored for Sickle cell Anemia which is a disease of major concern among these ethnic populations. This genetic disorder developed due to the sickling of Red Blood Cells has increased during the past few decades. The Tribes, as they live in close encounter with the forest regions and have strict social cultural barriers, face difficulty in availing treatment or counseling from the Sickle Cell Research Center (SCRC) and other NGOs like NAWA and AHWINI in the region. It was observed that many factors such as landscape terrain, climatic conditions and improper roads tend to hinder the access to appropriate health care. The SCRC in Gudalur region is a facility established to monitor the disease cases inspite of these influencing factors. On analyzing the year bound age wise classification among male and female patients, certain dropouts in cases were observed which may be due to inaccessible condition or migration of the patient. In our study, Landscape heterogeneity mapping for different climatic seasons was done in ArcGIS 10.1. For this, contour and terrain maps, road networks and villages were prepared and factors that determine Terrain Difficulty were assessed. Vegetation mapping using IRS satellite images for the study region was attempted and associated with the landscape map. A risk analysis was proposed based on terrain difficulty and access to the nearest Health care Center. Based on this, the above factors alternate routes were suggested to access the difficult areas.

Numerical simulations of windblown dust over complex terrain: the Fiambalá Basin episode in June 2015

NASA Astrophysics Data System (ADS)

Mingari, Leonardo A.; Collini, Estela A.; Folch, Arnau; Báez, Walter; Bustos, Emilce; Soledad Osores, María; Reckziegel, Florencia; Alexander, Peter; Viramonte, José G.

2017-06-01

On 13 June 2015, the London Volcanic Ash Advisory Centre (VAAC) warned the Buenos Aires VAAC about a possible volcanic eruption from the Nevados Ojos del Salado volcano (6879 m), located in the Andes mountain range on the border between Chile and Argentina. A volcanic ash cloud was detected by the SEVIRI instrument on board the Meteosat Second Generation (MSG) satellites from 14:00 UTC on 13 June. In this paper, we provide the first comprehensive description of this event through observations and numerical simulations. Our results support the hypothesis that the phenomenon was caused by wind remobilization of ancient pyroclastic deposits (ca. 4.5 ka Cerro Blanco eruption) from the Bolsón de Fiambalá (Fiambalá Basin) in northwestern Argentina. We have investigated the spatiotemporal distribution of aerosols and the emission process over complex terrain to gain insight into the key role played by the orography and the condition that triggered the long-range transport episode. Numerical simulations of windblown dust were performed using the ARW (Advanced Research WRF) core of the WRF (Weather Research and Forecasting) model (WRF-ARW) and FALL3D modeling system with meteorological fields downscaled to a spatial resolution of 2 km in order to resolve the complex orography of the area. Results indicate that favorable conditions to generate dust uplifting occurred in northern Fiambalá Basin, where orographic effects caused strong surface winds. According to short-range numerical simulations, dust particles were confined to near-ground layers around the emission areas. In contrast, dust aerosols were injected up to 5-6 km high in central and southern regions of the Fiambalá Basin, where intense ascending airflows are driven by horizontal convergence. Long-range transport numerical simulations were also performed to model the dust cloud spreading over northern Argentina. Results of simulated vertical particle column mass were compared with the MSG-SEVIRI retrieval product. We tested two numerical schemes: with the default configuration of the FALL3D model, we found difficulties to simulate transport through orographic barriers, whereas an alternative configuration, using a numerical scheme to more accurately compute the horizontal advection in abrupt terrains, substantially improved the model performance.

Air pollution modeling over very complex terrain: An evaluation of WRF-Chem over Switzerland for two 1-year periods

NASA Astrophysics Data System (ADS)

Ritter, Mathias; Müller, Mathias D.; Tsai, Ming-Yi; Parlow, Eberhard

2013-10-01

The fully coupled chemistry module (WRF-Chem) within the Weather Research and Forecasting (WRF) model has been implemented over a Swiss domain for the years 2002 and 1991. The very complex terrain requires a high horizontal resolution (2 × 2 km2), which is achieved by nesting the Swiss domain into a coarser European one. The temporal and spatial distribution of O3, NO2 and PM10 as well as temperature and solar radiation are evaluated against ground-based measurements. The model performs well for the meteorological parameters with Pearson correlation coefficients of 0.92 for temperature and 0.88-0.89 for solar radiation. Temperature has root mean square errors (RMSE) of 3.30 K and 3.51 K for 2002 and 1991 and solar radiation has RMSEs of 122.92 and 116.35 for 2002 and 1991, respectively. For the modeled air pollutants, a multi-linear regression post-processing was used to eliminate systematic bias. Seasonal variations of post-processed air pollutants are represented correctly. However, short-term peaks of several days are not captured by the model. Averaged daily maximum and daily values of O3 achieved Pearson correlation coefficients of 0.69-0.77 whereas averaged NO2 and PM10 had the highest correlations for yearly average values (0.68-0.78). The spatial distribution reveals the importance of PM10 advection from the Po valley to southern Switzerland (Ticino). The absolute errors are ranging from - 10 to 15 μg/m3 for ozone, - 9 to 3 μg/m3 for NO2 and - 4 to 3 μg/m3 for PM10. However, larger errors occur along heavily trafficked roads, in street canyons or on mountains. We also compare yearly modeled results against a dedicated Swiss dispersion model for NO2 and PM10. The dedicated dispersion model has a slightly better statistical performance, but WRF-Chem is capable of computing the temporal evolution of three-dimensional data for a variety of air pollutants and meteorological parameters. Overall, WRF-Chem with the application of post-processing algorithms can produce encouraging statistical values over very complex terrain which are competitive with similar studies.

Proceedings of a workshop on slope stability: problems and solutions in forest management; Seattle, Washington; February 6-8, 1984.

Treesearch

Doug Swanston

1985-01-01

mountainous areas of the western United States, Canada, and Alaska is severely restricted by unstable terrain that is susceptible to soil movement varying from surface creep to catastrophic landslides. Management practices that might trigger or increase such disturbance are increasingly subject to public scrutiny.Land management-planning as required by the...

Evaluation of methods for delineating riparian zones in a semi-arid montane watershed

Treesearch

Jessica A. Salo; David M. Theobald; Thomas C. Brown

2016-01-01

Riparian zones in semi-arid, mountainous regions provide a disproportionate amount of the available wildlife habitat and ecosystem services. Despite their importance, there is little guidance on the best way to map riparian zones for broad spatial extents (e.g., large watersheds) when detailed maps from field data or high-resolution imagery and terrain data...

A probabilistic model of debris-flow delivery to stream channels, demonstrated for the Coast Range of Oregon, USA

Treesearch

Daniel J. Miller; Kelly M. Burnett

2008-01-01

Debris flows are important geomorphic agents in mountainous terrains that shape channel environments and add a dynamic element to sediment supply and channel disturbance. Identification of channels susceptible to debris-flow inputs of sediment and organic debris, and quantification of the likelihood and magnitude of those inputs, are key tasks for characterizing...

Root distribution and seasonal water status in weathered granitic bedrock under chaparral

Treesearch

P. D. Sternberg; M. A. Anderson; R. C. Graham; J. L. Beyers; K. R. Tice

1996-01-01

Soils in mountainous terrain are often thin and unable to store sufficient water to support existing vegetation through dry seasons. This observation has led to speculation about the role of bedrock in supporting plant growth in natural ecosystems, since weathered bedrocks often have appreciable porosity and, like soil, can store and transmit water. This study, within...

Alaska research natural areas: 2. Limestone jags.

Treesearch

G.P. Juday

1989-01-01

The 2083-hectare Limestone Jags Research Natural Area in the White Mountains National Recreation Area of central Alaska contains old limestone terrain features––caves, natural bridges, disappearing streams, and cold springs in a subarctic setting. A limestone dissolution joint-type cave in the area is one of the largest reported in high-latitude North America. A...

A resource at the crossroads: a history of the central hardwoods

Treesearch

Ray R., Jr. Hicks

1997-01-01

The Central Hardwood Forest is an oak dominated deciduous forest that stretches from Massachusetts to Arkansas and occurs in hilly to mountainous terrain. It is the largest and most extensive temperate deciduous forest in the world. During the past 20 million years or so, angiosperms have been gradually replacing gymnosperms as the dominant plant form on earth, and...

Late winter and early spring home range and habitat use of the endangered Carolina northern flying squirrel in western North Carolina

Treesearch

W. Mark Ford; Christine A. Kelly; Jane L. Rodrigue; Richard H. Odom; Douglas Newcomb; L. Michelle Gilley; Corrine A. Diggins

2014-01-01

The Carolina northern flying squirrel Glaucomys sabrinus coloratus is an endangered subspecies that is restricted to high elevation forests in the southern Appalachian Mountains. Owing to rugged terrain and nocturnal habits, the subspecies' natural history, home range characteristics and habitat preferences are poorly known. We radio-tracked 3...

Topology and the Lay of the Land: A Mathematician on the Topographer's Turf.

ERIC Educational Resources Information Center

Shubin, Mikhail

1992-01-01

Presents a proof of Euler's Theorem on polyhedra by relating the theorem to the field of modern topology, specifically to the topology of relief maps. An analogous theorem involving the features of mountain summits, basins, and passes on a terrain is proved and related to the faces, vertices, and edges on a convex polyhedron. (MDH)

F-16 MMC Strafe in Mountainous Terrain

DTIC Science & Technology

2016-04-01

19 Figure 10. Steep fast (480 KIAS ) high-angle strafe...a fast (480 KIAS in this example) approach varies from the recovery radius (4000 feet in this case) and down track range prior to recovery initiation...Steep fast (480 KIAS ) high-angle strafe Alternate Analysis The F-16 community, to some extent, has adopted high-angle strafe as the de facto strafe

An old-growth definition for xeric pine and pine-oak woodlands

Treesearch

Paul A. Murphy; Gregory J. Nowacki

1997-01-01

The old-growth characteristics of xeric pine and pine-oak woodlands are summarized from a survey of the available scientific literature. This type occurs throughout the South and is usually found as small inclusions on ridgetops and south-facing slopes in the mountains or on excessively drained, sandy uplands in gentle terrain. Historically, this type has had frequent...

Erosion control on logging roads in the Appalachians

Treesearch

James N. Kochenderfer; James N. Kochenderfer

1970-01-01

In the steep terrain of the Appalachian Mountains much damage to forest streams is caused by erosion on logging roads. Muddy water that is unsuitable for fish, swimming, or human consumption often can be traced to these eroding roads. This paper has been prepared to sum up what land managers know about preventing and controlling erosion on logging roads in the...

Effects of off-road recreation on mule deer and elk.

Treesearch

Michael J. Wisdom; Alan A. Ager; Haiganoush K. Preisler; Norman J. Cimon; Bruce K. Johnson

2004-01-01

Off-road recreation is increasing rapidly in the United States, especially on public land (Havlick 2002, U.S. Department of Agriculture Forest Service 2004). An expansive network of roads provides easy access to much public land, which facilitates off-road uses in the form of all-terrain vehicles (ATVs), horses, mountain bikes and foot traffic. No research, however,...

Home destruction examination: Grass Valley Fire, Lake Arrowhead, California

Treesearch

Jack D. Cohen; Richard D. Stratton

2008-01-01

The Grass Valley Fire started October 22, 2007 at approximately 0508, one-mile west of Lake Arrowhead in the San Bernardino Mountains. Fuel and weather conditions were extreme due to drought, dry Santa Ana winds, and chaparral and conifer vegetation on steep terrain. The fire proceeded south through the Grass Valley drainage one-mile before impacting an area of dense...

Ergonomic factors and production target evaluation in eucalyptus timber harvesting operations in mountainous terrains.

PubMed

de Souza, Amaury Paulo; Minette, Luciano José; Sanches, André Luis Petean; da Silva, Emília Pio; Rodrigues, Valéria Antônia Justino; de Oliveira, Luciana Aparecida

2012-01-01

There are several forest operations involved in Eucalyptus timber harvesting. This study was carried out during brush-cutting; tree felling, bucking, delimbing, piling and manual extraction operations, with the following objectives: a) analyzing, ergonomically, two systems of brush-cutting: one manual and the other semi-mechanized, using two different machines; b) ergonomically evaluating three different brands of pruner machines used in delimbing felled trees. c) determining the feasible target of productivity as a function of ergonomic factors relevant to establish the time of resting pauses for workers in manual and semi-mechanized timber harvesting systems in mountainous terrain. Brush-cutting, either manual or semimechanized, is an activity carried out prior to timber harvesting. It is usually a hard work, with low productivity when compared with mechanized systems. Pruner machines have been used by forest companies, due to the great possibilities to improve productivity, quality and the health of workers. Ergonomics is a discipline that promotes the adequacy of work to the physical and mental characteristics of human beings, seeking to design production systems and products considering relevant aspects, including social, organizational and environmental factors. Companies should consider the ergonomic factor in the determination of daily worker production targets.

Application of digital terrain data to quantify and reduce the topographic effect on LANDSAT data

NASA Technical Reports Server (NTRS)

Justice, C. O.; Wharton, S. W.; Holben, B. N. (Principal Investigator)

1980-01-01

Integration of LANDSAT multispectral scanner (MSS) data with 30 m U.S. Geological Survey (USGS) digital terrain data was undertaken to quantify and reduce the topographic effect on imagery of a forested mountain ridge test site in central Pennsylvania. High Sun angle imagery revealed variation of as much as 21 pixel values in data for slopes of different angles and aspects with uniform surface cover. Large topographic effects were apparent in MSS 4 and 5 was due to a combination of high absorption by the forest cover and the MSS quantization. Four methods for reducing the topographic effect were compared. Band ratioing of MSS 6/5 and MSS 7/5 did not eliminate the topographic effect because of the lack of variation in MSS 4 and 5 radiances. The three radiance models examined to reduce the topographic effect required integration of the digital terrain data. Two Lambertian models increased the variation in the LANDSAT radiances. The nonLambertian model considerably reduced (86 per cent) the topographic effect in the LANDSAT data. The study demonstrates that high quality digital terrain data, as provided by the USGS digital elevation model data, can be used to enhance the utility of multispectral satellite data.

The First Six Months of Iapetus Observations by the Cassini ISS Camera

NASA Technical Reports Server (NTRS)

Denk, T.; Neukum, G.; Helfenstein, P.; Thomas, P. C.; Turtle, E. P.; McEwen, A. S.; Roatsch, T.; Veverka, J.

2005-01-01

Since Saturn arrival in June 2004, Iapetus has been studied intensively by the Cassini ISS camera [1] at various ranges. The first of two relatively close flybys in the primary mission occurred on Dec 31, 2004 at an altitude of approx.123,400 km over the northern leading hemisphere, resulting in images with a minimum pixel scale of 740 m. Detailed results of this flyby are given in [2], while this abstract covers the observations obtained earlier. Among the most important discoveries are: (a) Four giant impact basins with diameters between 390 and 550 km were detected, three of them are located in the dark terrain [3]. (b) Data revealed a >1300 km long ridge that marks exactly Iapetus' equator within the dark terrain. Individual mountains within the western part of the ridge reach heights of approx.20 km over surrounding terrain [3]. (c) Impact craters were confirmed to be the main geological feature within the dark terrain and at high southern latitudes. (d) There are numerous craters with dark walls roughly facing towards the central parts of the dark hemisphere [3]. (e) Almost all parts of Iapetus have been imaged at least at low resolution (< 60 km/pxl).

Quasi-analytical treatment of spatially averaged radiation transfer in complex terrain

NASA Astrophysics Data System (ADS)

LöWe, H.; Helbig, N.

2012-10-01

We provide a new quasi-analytical method to compute the subgrid topographic influences on the shortwave radiation fluxes and the effective albedo in complex terrain as required for large-scale meteorological, land surface, or climate models. We investigate radiative transfer in complex terrain via the radiosity equation on isotropic Gaussian random fields. Under controlled approximations we derive expressions for domain-averaged fluxes of direct, diffuse, and terrain radiation and the sky view factor. Domain-averaged quantities can be related to a type of level-crossing probability of the random field, which is approximated by long-standing results developed for acoustic scattering at ocean boundaries. This allows us to express all nonlocal horizon effects in terms of a local terrain parameter, namely, the mean-square slope. Emerging integrals are computed numerically, and fit formulas are given for practical purposes. As an implication of our approach, we provide an expression for the effective albedo of complex terrain in terms of the Sun elevation angle, mean-square slope, the area-averaged surface albedo, and the ratio of atmospheric direct beam to diffuse radiation. For demonstration we compute the decrease of the effective albedo relative to the area-averaged albedo in Switzerland for idealized snow-covered and clear-sky conditions at noon in winter. We find an average decrease of 5.8% and spatial patterns which originate from characteristics of the underlying relief. Limitations and possible generalizations of the method are discussed.

Boundary-layer processes: key findings from MATERHORN-X field campaigns

NASA Astrophysics Data System (ADS)

Di Sabatino, Silvana; Leo, Laura S.; Pardyjak, Eric R.; Fernando, Harindra JS

2017-04-01

Understanding of atmospheric boundary-layer processes in complex terrain continues to be an active area of research considering its profound implications on numerical weather prediction (WP). It is largely recognized that nocturnal circulation, non-stationary processes involved in evening and morning transitions as well gusty conditions near mountains are poorly captured by current WP models. The search for novel understanding of boundary-layer phenomena especially in critical conditions for WP models has been one of the goals of the interdisciplinary Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program (2011-2016). The program developed with four main pillars: modelling (MATERHORN-M), experiments (MATERHORN-X), technology (MATERHORN-T), and parameterizations (MATERHORN-P), all synergistically working to meet new scientific challenges, address them effectively through dedicated field and laboratory studies, and transfer the acquired knowledge for model improvements. Specifically, MATERHORN-X is at the core of the MATERHORN program. It was built upon two major field experiments carried out in 31 September-October 2012 and in May 2013 at the Granite Mountain Atmospheric Science Testbed 32 (GMAST) of the Dugway Proving Ground (DPG). In this talk we will focus on results of data analyses from MATERHORN-X with emphasis on several aspects of the nocturnal circulation under low synoptic forcing when stable stratification occurs. The first part of the talk will discuss the evolution of nocturnal flows including both evening transitions on slopes and valleys as well as the occurrence of isolated flow bursts under very stable conditions. As far as the former is concerned we report on our latest understanding of mechanisms leading to evening transitions (e.g. shadow front, slab flow, and transitional front). As far as the latter is concerned, it is hypothesized that a link exists between isolated bursts in turbulent kinetic energy and low-level jets structure, a feature which is commonly found in the first 50-100 m from the ground. The second part of the talk will discuss the interaction between an isolated hill and an approaching (undisturbed) stably-stratified flow with emphasis on the dividing streamline concept. The hill was located northwest of and close to the Granite Mountain, and was approximately 60m in height. A suite of (smoke) flow-visualization, remote sensing and in-situ measurement assets were deployed. At small Froude numbers (Fr<1), a stratified flow approaching the hill either possesses sufficient kinetic energy to pass over the summit or else flows around the sides, with the dividing streamline separating the two scenarios. By applying a logarithmic approach velocity profile to the well-known Sheppard's formula based on simple energetics, an explicit representation for the dividing streamline height was derived and a new set of parameters were identified to determine the dividing streamline height. The analysis shows that there will always be a dividing streamline for real atmospheric stratified shear flows. This has relevant implications for modelling air-flow and dispersion in mountainous regions.

Relations between basin characteristics and stream water chemistry in alpine/subalpine basins in Rocky Mountain National Park, Colorado

USGS Publications Warehouse

Clow, David W.; Sueker, Julie K.

2000-01-01

Relations between stream water chemistry and topographic, vegetative, and geologic characteristics of basins were evaluated for nine alpine/subalpine basins in Rocky Mountain National Park, Colorado, to identify controlling parameters and to better understand processes governing patterns in stream water chemistry. Fractional amounts of steep slopes (≥30°), unvegetated terrain, and young surficial debris within each basin were positively correlated to each other. These terrain features, which commonly occur on steep valley side slopes underlain by talus, were negatively correlated with concentrations of base cations, silica, and alkalinity and were positively correlated with nitrate, acidity, and runoff. These relations might result from the short residence times of water and limited soil development in the talus environment, which limit chemical weathering and nitrogen uptake. Steep, unvegetated terrains also tend to promote high Ca/Na ratios in stream water, probably because physical weathering rates in those areas are high. Physical weathering exposes fresh bedrock that contains interstitial calcite, which weathers relatively quickly. The fractional amounts of subalpine meadow and, to a lesser extent, old surficial debris in the basins were positively correlated to concentrations of weathering products and were negatively correlated to nitrate and acidity. These relations may reflect more opportunities for silicate weathering and nitrogen uptake in the lower‐energy environments of the valley floor, where soils are finer‐grained, older, and better developed and slopes are relatively flat. These results indicate that in alpine/subalpine basins, slope, vegetation (or lack thereof), and distribution and age of surficial materials are interrelated and can have major effects on stream water chemistry.

Multi-scale curvature for automated identification of glaciated mountain landscapes

NASA Astrophysics Data System (ADS)

Prasicek, Günther; Otto, Jan-Christoph; Montgomery, David; Schrott, Lothar

2014-05-01

Automated morphometric interpretation of digital terrain data based on impartial rule sets holds substantial promise for large dataset processing and objective landscape classification. However, the geomorphological realm presents tremendous complexity in the translation of qualitative descriptions into geomorphometric semantics. Here, the simple, conventional distinction of V-shaped fluvial and U-shaped glacial valleys is analyzed quantitatively using the relation of multi-scale curvature and drainage area. Glacial and fluvial erosion shapes mountain landscapes in a long-recognized and characteristic way. Valleys incised by fluvial processes typically have V-shaped cross-sections with uniform and moderately steep slopes, whereas glacial valleys tend to have U-shaped profiles and topographic gradients steepening with distance from valley floor. On a DEM, thalweg cells are determined by a drainage area cutoff and multiple moving window sizes are used to derive per-cell curvature over a variety of scales ranging from the vicinity of the flow path at the valley bottom to catchment sections fully including valley sides. The relation of the curvatures calculated for the user-defined minimum scale and the automatically detected maximum scale is presented as a novel morphometric variable termed Difference of Minimum Curvature (DMC). DMC thresholds determined from typical glacial and fluvial sample catchments are employed to identify quadrats of glaciated and non-glaciated mountain landscapes and the distinctions are validated by field-based geological and geomorphological maps. A first test of the novel algorithm at three study sites in the western United States and a subsequent application to Europe and western Asia demonstrate the transferability of the approach.

The first Australian gravimetric quasigeoid model with location-specific uncertainty estimates

NASA Astrophysics Data System (ADS)

Featherstone, W. E.; McCubbine, J. C.; Brown, N. J.; Claessens, S. J.; Filmer, M. S.; Kirby, J. F.

2018-02-01

We describe the computation of the first Australian quasigeoid model to include error estimates as a function of location that have been propagated from uncertainties in the EGM2008 global model, land and altimeter-derived gravity anomalies and terrain corrections. The model has been extended to include Australia's offshore territories and maritime boundaries using newer datasets comprising an additional {˜ }280,000 land gravity observations, a newer altimeter-derived marine gravity anomaly grid, and terrain corrections at 1^' ' }× 1^' ' } resolution. The error propagation uses a remove-restore approach, where the EGM2008 quasigeoid and gravity anomaly error grids are augmented by errors propagated through a modified Stokes integral from the errors in the altimeter gravity anomalies, land gravity observations and terrain corrections. The gravimetric quasigeoid errors (one sigma) are 50-60 mm across most of the Australian landmass, increasing to {˜ }100 mm in regions of steep horizontal gravity gradients or the mountains, and are commensurate with external estimates.

Objective high Resolution Analysis over Complex Terrain with VERA

NASA Astrophysics Data System (ADS)

Mayer, D.; Steinacker, R.; Steiner, A.

2012-04-01

VERA (Vienna Enhanced Resolution Analysis) is a model independent, high resolution objective analysis of meteorological fields over complex terrain. This system consists of a special developed quality control procedure and a combination of an interpolation and a downscaling technique. Whereas the so called VERA-QC is presented at this conference in the contribution titled "VERA-QC, an approved Data Quality Control based on Self-Consistency" by Andrea Steiner, this presentation will focus on the method and the characteristics of the VERA interpolation scheme which enables one to compute grid point values of a meteorological field based on irregularly distributed observations and topography related aprior knowledge. Over a complex topography meteorological fields are not smooth in general. The roughness which is induced by the topography can be explained physically. The knowledge about this behavior is used to define the so called Fingerprints (e.g. a thermal Fingerprint reproducing heating or cooling over mountainous terrain or a dynamical Fingerprint reproducing positive pressure perturbation on the windward side of a ridge) under idealized conditions. If the VERA algorithm recognizes patterns of one or more Fingerprints at a few observation points, the corresponding patterns are used to downscale the meteorological information in a greater surrounding. This technique allows to achieve an analysis with a resolution much higher than the one of the observational network. The interpolation of irregularly distributed stations to a regular grid (in space and time) is based on a variational principle applied to first and second order spatial and temporal derivatives. Mathematically, this can be formulated as a cost function that is equivalent to the penalty function of a thin plate smoothing spline. After the analysis field has been divided into the Fingerprint components and the unexplained part respectively, the requirement of a smooth distribution is applied to the latter component only (the Fingerprint field is rough by definition). In order to obtain the final analysis field, the unexplained component has to be combined with the weighted Fingerprint patterns. Operationally, VERA is carried out at our Department on an hourly basis analyzing temperature measurements, pressure, wind and precipitation observations for several domains of the whole world. VERA analyses are used for nowcasting purposes, for establishing climate databases and model verification. Furthermore, VERA can be interesting for everyone who possesses a PC but does not have access to a complex data assimilation system which is in general only available at numerical weather prediction centers.

Soil Temperature Variability in Complex Terrain measured using Distributed a Fiber-Optic Distributed Temperature Sensing

NASA Astrophysics Data System (ADS)

Seyfried, M. S.; Link, T. E.

2013-12-01

Soil temperature (Ts) exerts critical environmental controls on hydrologic and biogeochemical processes. Rates of carbon cycling, mineral weathering, infiltration and snow melt are all influenced by Ts. Although broadly reflective of the climate, Ts is sensitive to local variations in cover (vegetative, litter, snow), topography (slope, aspect, position), and soil properties (texture, water content), resulting in a spatially and temporally complex distribution of Ts across the landscape. Understanding and quantifying the processes controlled by Ts requires an understanding of that distribution. Relatively few spatially distributed field Ts data exist, partly because traditional Ts data are point measurements. A relatively new technology, fiber optic distributed temperature system (FO-DTS), has the potential to provide such data but has not been rigorously evaluated in the context of remote, long term field research. We installed FO-DTS in a small experimental watershed in the Reynolds Creek Experimental Watershed (RCEW) in the Owyhee Mountains of SW Idaho. The watershed is characterized by complex terrain and a seasonal snow cover. Our objectives are to: (i) evaluate the applicability of fiber optic DTS to remote field environments and (ii) to describe the spatial and temporal variability of soil temperature in complex terrain influenced by a variable snow cover. We installed fiber optic cable at a depth of 10 cm in contrasting snow accumulation and topographic environments and monitored temperature along 750 m with DTS. We found that the DTS can provide accurate Ts data (+/- .4°C) that resolves Ts changes of about 0.03°C at a spatial scale of 1 m with occasional calibration under conditions with an ambient temperature range of 50°C. We note that there are site-specific limitations related cable installation and destruction by local fauna. The FO-DTS provide unique insight into the spatial and temporal variability of Ts in a landscape. We found strong seasonal trends in Ts variability controlled by snow cover and solar radiation as modified by topography. During periods of spatially continuous snow cover Ts was practically homogeneous throughout. In the absence of snow cover, Ts is highly variable, with most of the variability attributable to different topographic units defined by slope and aspect. During transition periods when snow melts out, Ts is highly variable within the watershed and within topographic units. The importance of accounting for these relatively small scale effects is underscored by the fact that the overall range of Ts in study area 600 m long is similar to that of the much large RCEW with 900 m elevation gradient.

Predicting Individual Tree and Shrub Species Distributions with Empirically Derived Microclimate Surfaces in a Complex Mountain Ecosystem in Northern Idaho, USA

NASA Astrophysics Data System (ADS)

Holden, Z.; Cushman, S.; Evans, J.; Littell, J. S.

2009-12-01

The resolution of current climate interpolation models limits our ability to adequately account for temperature variability in complex mountainous terrain. We empirically derive 30 meter resolution models of June-October day and nighttime temperature and April nighttime Vapor Pressure Deficit (VPD) using hourly data from 53 Hobo dataloggers stratified by topographic setting in mixed conifer forests near Bonners Ferry, ID. 66%, of the variability in average June-October daytime temperature is explained by 3 variables (elevation, relative slope position and topographic roughness) derived from 30 meter digital elevation models. 69% of the variability in nighttime temperatures among stations is explained by elevation, relative slope position and topographic dissection (450 meter window). 54% of variability in April nighttime VPD is explained by elevation, soil wetness and the NDVIc derived from Landsat. We extract temperature and VPD predictions at 411 intensified Forest Inventory and Analysis plots (FIA). We use these variables with soil wetness and solar radiation indices derived from a 30 meter DEM to predict the presence and absence of 10 common forest tree species and 25 shrub species. Classification accuracies range from 87% for Pinus ponderosa , to > 97% for most other tree species. Shrub model accuracies are also high with greater than 90% accuracy for the majority of species. Species distribution models based on the physical variables that drive species occurrence, rather than their topographic surrogates, will eventually allow us to predict potential future distributions of these species with warming climate at fine spatial scales.

Lithologic Effects on Landscape Response to Base Level Changes: A Modeling Study in the Context of the Eastern Jura Mountains, Switzerland

NASA Astrophysics Data System (ADS)

Yanites, Brian J.; Becker, Jens K.; Madritsch, Herfried; Schnellmann, Michael; Ehlers, Todd A.

2017-11-01

Landscape evolution is a product of the forces that drive geomorphic processes (e.g., tectonics and climate) and the resistance to those processes. The underlying lithology and structural setting in many landscapes set the resistance to erosion. This study uses a modified version of the Channel-Hillslope Integrated Landscape Development (CHILD) landscape evolution model to determine the effect of a spatially and temporally changing erodibility in a terrain with a complex base level history. Specifically, our focus is to quantify how the effects of variable lithology influence transient base level signals. We set up a series of numerical landscape evolution models with increasing levels of complexity based on the lithologic variability and base level history of the Jura Mountains of northern Switzerland. The models are consistent with lithology (and therewith erodibility) playing an important role in the transient evolution of the landscape. The results show that the erosion rate history at a location depends on the rock uplift and base level history, the range of erodibilities of the different lithologies, and the history of the surface geology downstream from the analyzed location. Near the model boundary, the history of erosion is dominated by the base level history. The transient wave of incision, however, is quite variable in the different model runs and depends on the geometric structure of lithology used. It is thus important to constrain the spatiotemporal erodibility patterns downstream of any given point of interest to understand the evolution of a landscape subject to variable base level in a quantitative framework.

Significant effect of topographic normalization of airborne LiDAR data on the retrieval of plant area index profile in mountainous forests

NASA Astrophysics Data System (ADS)

Liu, Jing; Skidmore, Andrew K.; Heurich, Marco; Wang, Tiejun

2017-10-01

As an important metric for describing vertical forest structure, the plant area index (PAI) profile is used for many applications including biomass estimation and wildlife habitat assessment. PAI profiles can be estimated with the vertically resolved gap fraction from airborne LiDAR data. Most research utilizes a height normalization algorithm to retrieve local or relative height by assuming the terrain to be flat. However, for many forests this assumption is not valid. In this research, the effect of topographic normalization of airborne LiDAR data on the retrieval of PAI profile was studied in a mountainous forest area in Germany. Results show that, although individual tree height may be retained after topographic normalization, the spatial arrangement of trees is changed. Specifically, topographic normalization vertically condenses and distorts the PAI profile, which consequently alters the distribution pattern of plant area density in space. This effect becomes more evident as the slope increases. Furthermore, topographic normalization may also undermine the complexity (i.e., canopy layer number and entropy) of the PAI profile. The decrease in PAI profile complexity is not solely determined by local topography, but is determined by the interaction between local topography and the spatial distribution of each tree. This research demonstrates that when calculating the PAI profile from airborne LiDAR data, local topography needs to be taken into account. We therefore suggest that for ecological applications, such as vertical forest structure analysis and modeling of biodiversity, topographic normalization should not be applied in non-flat areas when using LiDAR data.

Adding Complex Terrain and Stable Atmospheric Condition Capability to the OpenFOAM-based Flow Solver of the Simulator for On/Offshore Wind Farm Applications (SOWFA): Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churchfield, M. J.; Sang, L.; Moriarty, P. J.

This paper describes changes made to NREL's OpenFOAM-based wind plant aerodynamics solver such that it can compute the stably stratified atmospheric boundary layer and flow over terrain. Background about the flow solver, the Simulator for Off/Onshore Wind Farm Applications (SOWFA) is given, followed by details of the stable stratification/complex terrain modifications to SOWFA, along with somepreliminary results calculations of a stable atmospheric boundary layer and flow over a simply set of hills.

Adding Complex Terrain and Stable Atmospheric Condition Capability to the Simulator for On/Offshore Wind Farm Applications (SOWFA) (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churchfield, M. J.

This presentation describes changes made to NREL's OpenFOAM-based wind plant aerodynamics solver so that it can compute the stably stratified atmospheric boundary layer and flow over terrain. Background about the flow solver, the Simulator for Off/Onshore Wind Farm Applications (SOWFA) is given, followed by details of the stable stratification/complex terrain modifications to SOWFA, along with some preliminary results calculations of a stable atmospheric boundary layer and flow over a simple set of hills.

Nocturnal Reversed Flows Above Parallel Ridges in Perdigão, Portugal

NASA Astrophysics Data System (ADS)

Krishnamurthy, R.; Fernando, H. J.; Leo, L. S.; Vassallo, D.; Hocut, C. M.; Creegan, E.; Rodriguez, C. V.; Palma, J. L.

2017-12-01

Prediction of topographically forced or induced wind events is extremely important for dispersion modeling and wind energy studies in complex terrain. To improve the current understanding of micro-scale processes over complex terrain, a large-scale field experiment was conducted in Perdigão, Portugal from May 1st, 2017 to June 15th, 2017. Measurements over a periodic valley were performed using 52 meteorological met-masts, 30 Doppler Lidars (scanning & vertical profilers), 2 tethered lifting systems and other remote sensing instruments (Sodar-rass, wind profilers & radiometer), and radiosondes were released every 6 hours over the period of study. The observations showed several cases of flow reversals confined to a thin layer of 70 - 100 m above the ridge under stably stratified conditions. These flow reversals were mostly observed during the lee wave formation over the periodic valley. It was observed that the flow reversal occurs predominantly under two atmospheric conditions: a) presence of large recirculation zones on the lee side of the hill causing a pressure gradient between the lee-side floor and the mountain ridge, and b) local change in the horizontal pressure gradient due to differential heating rates of the neighboring valley atmospheres. Microscale flow simulations could capture these observed flow reversals. Based on the network of tower instruments and remote sensing devices, the development, structure and occurrences of the flow reversals are being analyzed and quantified. Since these flow reversals are observed within the rotor swept area of modern wind turbines, they would drastically increase the fatigue loads on wind turbine blades. This presentation will include reversed flow observations from several synchronized scanning Doppler Lidars and meteorological towers and a theoretical framework for reverse flow over parallel valleys.

Local Climate Changes Forced by Changes in Land Use and topography in the Aburrá Valley, Colombia.

NASA Astrophysics Data System (ADS)

Zapata Henao, M. Z.; Hoyos Ortiz, C. D.

2017-12-01

One of the challenges in the numerical weather models is the adequate representation of soil-vegetation-atmosphere interaction at different spatial scales, including scenarios with heterogeneous land cover and complex mountainous terrain. The interaction determines the energy, mass and momentum exchange at the surface and could affect different variables including precipitation, temperature and wind. In order to quantify the long-term climate impact of changes in local land use and to assess the role of topography, two numerical experiments were examined. The first experiment allows assessing the continuous growth of urban areas within the Aburrá Valley, a complex terrain region located in Colombian Andes. The Weather Research Forecast model (WRF) is used as the basis of the experiment. The basic setup involves two nested domains, one representing the continental scale (18 km) and the other the regional scale (2 km). The second experiment allows drastic topography modification, including changing the valley configuration to a plateau. The control run for both experiments corresponds to a climatological scenario. In both experiments the boundary conditions correspond to the climatological continental domain output. Surface temperature, surface winds and precipitation are used as the main variables to compare both experiments relative to the control run. The results of the first experiment show a strong relationship between land cover and the variables, specially for surface temperature and wind speed, due to the strong forcing land cover imposes on the albedo, heat capacity and surface roughness, changing temperature and wind speed magnitudes. The second experiment removes the winds spatial variability related with hill slopes, the direction and magnitude are modulated only by the trade winds and roughness of land cover.

Topographic View of Ceres Mountain

NASA Image and Video Library

2015-09-30

This view, made using images taken by NASA's Dawn spacecraft, features a tall conical mountain on Ceres. Elevations span a range of about 5 miles (8 kilometers) from the lowest places in this region to the highest terrains. Blue represents the lowest elevation, and brown is the highest. The white streaks seen running down the side of the mountain are especially bright parts of the surface. The image was generated using two components: images of the surface taken during Dawn's High Altitude Mapping Orbit (HAMO) phase, where it viewed the surface at a resolution of about 450 feet (140 meters) per pixel, and a shape model generated using images taken at varying sun and viewing angles during Dawn's lower-resolution Survey phase. The image of the region is color-coded according to elevation, and then draped over the shape model to give this view. http://photojournal.jpl.nasa.gov/catalog/PIA19976

Pluto Majestic Mountains, Frozen Plains and Foggy Hazes

NASA Image and Video Library

2015-09-17

Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA's New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto's horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights more than a dozen layers of haze in Pluto's tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide. http://photojournal.jpl.nasa.gov/catalog/PIA19948

How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change?

EPA Science Inventory

We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site...

Digital mapping of mountain snowcover under European conditions. [Dischma Valley and Landwasser, Davos-Grisons, Switzerland

NASA Technical Reports Server (NTRS)

Haefner, H. (Principal Investigator)

1980-01-01

The author has identified the following significant results. A method for monitoring the snow cover in high mountain terrain such as the Swiss Alps includes the rapid classification of multitemporal data for small watersheds with very high accuracy. In addition to LANDSAT channels 4,5,6 and 7 an artificial channel was created containing the average altitude information of each pixel and allowing a subdivision of the watershed in accordance to the requirements of the runoff model. Even in very small watersheds of about 40 sq km the results achieved from LANDSAT data are at least as accurate as the ones gained from measurements of orthophotographs.

A MacCormack-TVD finite difference method to simulate the mass flow in mountainous terrain with variable computational domain

NASA Astrophysics Data System (ADS)

Ouyang, Chaojun; He, Siming; Xu, Qiang; Luo, Yu; Zhang, Wencheng

2013-03-01

A two-dimensional mountainous mass flow dynamic procedure solver (Massflow-2D) using the MacCormack-TVD finite difference scheme is proposed. The solver is implemented in Matlab on structured meshes with variable computational domain. To verify the model, a variety of numerical test scenarios, namely, the classical one-dimensional and two-dimensional dam break, the landslide in Hong Kong in 1993 and the Nora debris flow in the Italian Alps in 2000, are executed, and the model outputs are compared with published results. It is established that the model predictions agree well with both the analytical solution as well as the field observations.

New distributed radar technology based on UAV or UGV application

NASA Astrophysics Data System (ADS)

Molchanov, Pavlo A.; Contarino, Vincent M.

2013-05-01

Regular micro and nano radars cannot provide reliable tracking of low altitude low profile aerial targets in urban and mountain areas because of reflection and re-reflections from buildings and terrain. They become visible and vulnerable to guided missiles if positioned on a tower or blimp. Doppler radar cannot distinguish moving cars and small low altitude aerial targets in an urban area. A new concept of pocket size distributed radar technology based on the application of UAV (Unmanned Air Vehicles), UGV (Unmanned Ground Vehicles) is proposed for tracking of low altitude low profile aerial targets at short and medium distances for protection of stadium, camp, military facility in urban or mountain areas.

Waste management outlook for mountain regions: Sources and solutions.

PubMed

Semernya, Larisa; Ramola, Aditi; Alfthan, Björn; Giacovelli, Claudia

2017-09-01

Following the release of the global waste management outlook in 2015, the United Nations Environment Programme (UN Environment), through its International Environmental Technology Centre, is elaborating a series of region-specific and thematic waste management outlooks that provide policy recommendations and solutions based on current practices in developing and developed countries. The Waste Management Outlook for Mountain Regions is the first report in this series. Mountain regions present unique challenges to waste management; while remoteness is often associated with costly and difficult transport of waste, the potential impact of waste pollutants is higher owing to the steep terrain and rivers transporting waste downstream. The Outlook shows that waste management in mountain regions is a cross-sectoral issue of global concern that deserves immediate attention. Noting that there is no 'one solution fits all', there is a need for a more landscape-type specific and regional research on waste management, the enhancement of policy and regulatory frameworks, and increased stakeholder engagement and awareness to achieve sustainable waste management in mountain areas. This short communication provides an overview of the key findings of the Outlook and highlights aspects that need further research. These are grouped per source of waste: Mountain communities, tourism, and mining. Issues such as waste crime, plastic pollution, and the linkages between exposure to natural disasters and waste are also presented.

Local-scale stratigraphy of grooved terrain on Ganymede

NASA Technical Reports Server (NTRS)

Murchie, Scott L.; Head, James W.; Helfenstein, Paul; Plescia, Jeffrey B.

1987-01-01

The surface of the Jovian satellite, Ganymede, is divided into two main units, dark terrain cut by arcuate and subradial furrows, and light terrain consisting largely of areas with pervasive U-shaped grooves. The grooved terrain may be subdivided on the basis of pervasive morphology of groove domains into four terrain types: (1) elongate bands of parallel grooves (groove lanes); (2) polygonal domains of parallel grooves (grooved polygons); (3) polygonal domains of two orthogonal groove sets (reticulate terrain); and (4) polygons having two to several complexly cross-cutting groove sets (complex grooved terrain). Reticulate terrain is frequently dark and not extensively resurfaced, and grades to a more hummocky terrain type. The other three grooved terrain types have almost universally been resurfaced by light material during their emplacement. The sequence of events during grooved terrain emplacement has been investigated. An attempt is made to integrate observed geologic and tectonic patterns to better constrain the relative ages and styles of emplacement of grooved terrain types. A revised model of grooved terrain emplacement is proposed and is tested using detailed geologic mapping and measurement of crater density.

Stump-to-mill timber production cost equations for cable logging eastern hardwoods

Treesearch

Chris B. LeDoux; Chris B. LeDoux

1985-01-01

Logging cost simulators and data from logging cost studies have been assembled and converted into a series of equations that can be used to estimate the stump-to-mill cost of cable logging in mountainous terrain in the Eastern United States. These equations include the use of two small and four mediumsize cable yarders and are appropriate for harvested trees ranging in...

Emergency watershed protection measures in highly unstable terrain on the Blake Fire, Six Rivers National Forest, 1987

Treesearch

Mark E. Smith; Kenneth A. Wright

1989-01-01

The Blake Fire burned about 730 ha of mature timber on the west slope of South Fork Mountain in northwestern California. Many steep innergorge and landslide headwall areas burned very hot, killing most large trees and consuming much of the large organic debris in unstable drainages. This created a potential for adverse effects on downstream fisheries from landsliding...

Weather in Mountainous Terrain (Overcoming Scientific Barriers to Weather Support)

DTIC Science & Technology

2011-02-15

been more effective. Similarly, profiler data is more effective than surface observations. The satellite data are potentially valuable as an... Satellite data can play an important role in model validation, but accuracy has been an issue. Turbulence 1. The classical parameterizations for... data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this

Advanced Structural Concepts for Weapons Storage - Flat and Mountainous Terrains.

DTIC Science & Technology

1983-06-01

be required in the Maintenance Area. 7. WATER AND WASTE WATER. Water supply and wastewater collection systems are assumed to be available. It is...Ufceooa w aWdoo.amwa.. ,FC.hc OU 0 coos a (Peoi...sa dooedhI "- llcrnIT ENmca46t 0 Coos c I de odk BLACK A VEATCH 0oevLU Soedly _______ ONAgmagO 0 . 1 5

Errors in terrain-based model preditions caused by altered forest inventory plot locations in the Southern Appalachian Mountains, USA.

Treesearch

Huei-Jin Wang; Stephen Prisley; Philip Radtke; John Coulston

2012-01-01

Forest modeling applications that cover large geographic area can benefit from the use of widely-held knowledge about relationships between forest attributes and topographic variables. A noteworthy example involved the coupling of field survey data from the Forest Inventory Analysis (FIA) program of USDA Forest Service with digital elevation model (DEM) data in...

WindWizard: A New Tool for Fire Management Decision Support

Treesearch

Bret W. Butler; Mark Finney; Larry Bradshaw; Jason Forthofer; Chuck McHugh; Rick Stratton; Dan Jimenez

2006-01-01

A new software tool has been developed to simulate surface wind speed and direction at the 100m to 300 m scale. This tool is useful when trying to estimate fire behavior in mountainous terrain. It is based on widely used computational fluid dynamics technology and has been tested against measured wind flows. In recent years it has been used to support fire management...

Structures linking physical and biological processes in headwater streams of the Maybeso watershed, Southeast Alaska

Treesearch

Mason D. Bryant; Takashi Gomi; Jack J. Piccolo

2007-01-01

We focus on headwater streams originating in the mountainous terrain of northern temperate rain forests. These streams rapidly descend from gradients greater than 20% to less than 5% in U-shaped glacial valleys. We use a set of studies on headwater streams in southeast Alaska to define headwater stream catchments, link physical and biological processes, and describe...

Application of Remotely Piloted Vehicle (RPV) in monitoring and detecting watershed land use change and problem areas

Treesearch

Long-Ming Huang

2000-01-01

Improper cultivation of steep mountainous areas in Taiwan contributes to serious erosion and landslides. Regular patrol, detection, and administration of these problem areas has been an extremely difficult due to the steep and dangerous terrain of many of the forested watersheds in Taiwan. A remotely piloted vehicle (RPV) has been developed for various civil and...

Route choice in mountain navigation, Naismith's rule, and the equivalence of distance and climb.

PubMed

Scarf, Philip

2007-04-01

In this paper, I consider decision making about routes in mountain navigation. In particular, I discuss Naismith's rule, a method of calculating journey times in mountainous terrain, and its use for route choice. The rule is essentially concerned with the equivalence, in terms of time duration, between climb or ascent and distance travelled. Naismith himself described a rule that is purported to be based on trigonometry and simple assumptions about rate of ascent; his rule with regard to hill-walking implies that 1 m of ascent is equivalent to 7.92 m of horizontal travel (1:7.92). The analysis of data on fell running records presented here supports Naismith's rule and it is recommended that male runners and walkers use a 1:8 equivalence ratio and females a 1:10 ratio. The present findings are contrasted with those based on the analysis of data relating to treadmill running experiments (1:3.3), and with those based on the analysis of times for a mountain road-relay (1:4.4). Analysis of cycling data suggests a similar rule (1:8.2) for cycling on mountainous roads and tracks.

Evaluation of the Operational Multi-scale Environment model with Grid Adaptivity (OMEGA) for use in Wind Energy Applications in the Great Basin of Nevada

NASA Astrophysics Data System (ADS)

King, Kristien C.

In order to further assess the wind energy potential for Nevada, the accuracy of a computational meteorological model, the Operational Multi-scale Environment model with Grid Adaptivity (OMEGA), was evaluated by comparing simulation results with data collected from a wind monitoring tower near Tonopah, NV. The state of Nevada is characterized by high mountains and low-lying valleys, therefore, in order to determine the wind potential for the state, meteorological models that predict the wind must be able to accurately represent and account for terrain features and simulate topographic forcing with accuracy. Topographic forcing has a dominant role in the development and modification of mesoscale flows in regions of complex terrain, like Tonopah, especially at the level of wind turbine blade heights (~80 m). Additionally, model factors such as horizontal resolution, terrain database resolution, model physics, time of model initialization, stability regime, and source of initial conditions may each affect the ability of a mesoscale model to forecast winds correctly. The observational tower used for comparison was located at Stone Cabin, Nevada. The tower had both sonic anemometers and cup anemometers installed at heights of 40 m, 60 m, and 80 m above the surface. During a previous experiment, tower data were collected for the period February 9 through March 10, 2007 and compared to model simulations using the MM5 and WRF models at a number of varying horizontal resolutions. In this previous research, neither the MM5 nor the WRF showed a significant improvement in ability to forecast wind speed with increasing horizontal grid resolution. The present research evaluated the ability of OMEGA to reproduce point winds as compared to the observational data from the Stone Cabin Tower at heights of 40 m, 60 m, and 80 m. Unlike other mesoscale atmospheric models, OMEGA incorporates an unstructured triangular adaptive grid which allows for increased flexibility and accuracy in characterizing areas of complex terrain. Model sensitivity to horizontal grid resolution, initial conditions, and time of initialization were tested. OMEGA was run over three different horizontal grid resolutions with minimum horizontal edge lengths of: 18 km, 6 km, and 2 km. For each resolution, the model was initialized using both the Global Forecasting System (GFS) and North American Regional Reanalysis (NARR) to determine model sensitivity to initial conditions. For both the NARR and GFS initializations, the model was started at both 0000 UTC and 1200 UTC to determine the effect of start time and stability regime on the performance of the model. An additional intensive study into the model's performance was also conducted by a detailed evaluation of model results during two separate 24-hour periods, the first a period where the model performed well and the second a period where the model performed poorly, to determine which atmospheric factors most affect the predictive ability of the OMEGA model. The statistical results were then compared with the results from the MM5 and WRF simulations to determine the most appropriate model for wind energy potential studies in complex terrain.

Voyager 2 Color Image of Enceladus, Almost Full Disk

NASA Technical Reports Server (NTRS)

1990-01-01

This color Voyager 2 image mosaic shows the water-ice-covered surface of Enceladus, one of Saturn's icy moons. Enceladus' diameter of just 500 km would fit across the state of Arizona, yet despite its small size Enceladus exhibits one of the most interesting surfaces of all the icy satellites. Enceladus reflects about 90% of the incident sunlight (about like fresh-fallen snow), placing it among the most reflective objects in the Solar System. Several geologic terrains have superposed crater densities that span a factor of at least 500, thereby indicating huge differences in the ages of these terrains. It is possible that the high reflectivity of Enceladus' surface results from continuous deposition of icy particles from Saturn's E-ring, which in fact may originate from icy volcanoes on Enceladus' surface. Some terrains are dominated by sinuous mountain ridges from 1 to 2 km high (3300 to 6600 feet), whereas other terrains are scarred by linear cracks, some of which show evidence for possible sideways fault motion such as that of California's infamous San Andreas fault. Some terrains appear to have formed by separation of icy plates along cracks, and other terrains are exceedingly smooth at the resolution of this image. The implication carried by Enceladus' surface is that this tiny ice ball has been geologically active and perhaps partially liquid in its interior for much of its history. The heat engine that powers geologic activity here is thought to be elastic deformation caused by tides induced by Enceladus' orbital motion around Saturn and the motion of another moon, Dione.

Terrain Classification of Norwegian Slab Avalanche Accidents

ERIC Educational Resources Information Center

Hallandvik, Linda; Aadland, Eivind; Vikene, Odd Lennart

2016-01-01

It is difficult to rely on snow conditions, weather, and human factors when making judgments about avalanche risk because these variables are dynamic and complex; terrain, however, is more easily observed and interpreted. Therefore, this study aimed to investigate (1) the type of terrain in which historical fatal snow avalanche accidents in Norway…

Pluto: Pits and mantles on uplands north and east of Sputnik Planitia

NASA Astrophysics Data System (ADS)

Howard, Alan D.; Moore, Jeffrey M.; White, Oliver L.; Umurhan, Orkan M.; Schenk, Paul M.; Grundy, William M.; Schmitt, Bernard; Philippe, Sylvain; McKinnon, William B.; Spencer, John R.; Beyer, Ross A.; Stern, S. Alan; Ennico, Kimberly; Olkin, Cathy B.; Weaver, Harold A.; Young, Leslie A.; New Horizons Science Team

2017-09-01

The highlands region north and east of Sputnik Planitia can be subdivided into seven terrain types based on their physiographic expression. The northern rough uplands are characterized by jagged uplands and broad troughs, and it may contain a deeply-eroded ancient mantle. Dissected terrain has been interpreted to have been eroded by paleo-glaciation. The smooth uplands and pits terrain contains broad, rolling uplands surrounding complexes of pits, some of which contain smooth floors. The uplands are mantled by smooth-surfaced deposits possibly derived from adjacent pits through low-power explosive cryovolcanism or through slow vapor condensation. The eroded smooth uplands appear to have originally been smooth uplands and pits terrain modified by small-scale sublimation pitting. The bright pitted uplands features intricate texturing by reticulate ridges that may have originated by sublimation erosion, volatile condensation, or both. The bladed terrain is characterized by parallel ridges oriented north-south and is discussed in a separate paper. The dark uplands are mantled with reddish deposits that may be atmospherically deposited tholins. Their presence has affected long-term landform evolution. Widespread pit complexes occur on most of the terrain units. Most appear to be associated with tectonic lineations. Some pits are floored by broad expanses of ices, whereas most feature deep, conical depressions. A few pit complexes are enclosed by elevated rims of uncertain origin.

Integrating remote sensing and terrain data in forest fire modeling

NASA Astrophysics Data System (ADS)

Medler, Michael Johns

Forest fire policies are changing. Managers now face conflicting imperatives to re-establish pre-suppression fire regimes, while simultaneously preventing resource destruction. They must, therefore, understand the spatial patterns of fires. Geographers can facilitate this understanding by developing new techniques for mapping fire behavior. This dissertation develops such techniques for mapping recent fires and using these maps to calibrate models of potential fire hazards. In so doing, it features techniques that strive to address the inherent complexity of modeling the combinations of variables found in most ecological systems. Image processing techniques were used to stratify the elements of terrain, slope, elevation, and aspect. These stratification images were used to assure sample placement considered the role of terrain in fire behavior. Examination of multiple stratification images indicated samples were placed representatively across a controlled range of scales. The incorporation of terrain data also improved preliminary fire hazard classification accuracy by 40%, compared with remotely sensed data alone. A Kauth-Thomas transformation (KT) of pre-fire and post-fire Thematic Mapper (TM) remotely sensed data produced brightness, greenness, and wetness images. Image subtraction indicated fire induced change in brightness, greenness, and wetness. Field data guided a fuzzy classification of these change images. Because fuzzy classification can characterize a continuum of a phenomena where discrete classification may produce artificial borders, fuzzy classification was found to offer a range of fire severity information unavailable with discrete classification. These mapped fire patterns were used to calibrate a model of fire hazards for the entire mountain range. Pre-fire TM, and a digital elevation model produced a set of co-registered images. Training statistics were developed from 30 polygons associated with the previously mapped fire severity. Fuzzy classifications of potential burn patterns were produced from these images. Observed field data values were displayed over the hazard imagery to indicate the effectiveness of the model. Areas that burned without suppression during maximum fire severity are predicted best. Areas with widely spaced trees and grassy understory appear to be misrepresented, perhaps as a consequence of inaccuracies in the initial fire mapping.

Introduction Wind farms in complex terrains: an introduction

PubMed Central

Alfredsson, P. H.; Segalini, A.

2017-01-01

Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas—locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field. This article is part of the themed issue ‘Wind energy in complex terrains’. PMID:28265020

A sightability model for mountain goats

USGS Publications Warehouse

Rice, C.G.; Jenkins, K.J.; Chang, W.-Y.

2009-01-01

Unbiased estimates of mountain goat (Oreamnos americanus) populations are key to meeting diverse harvest management and conservation objectives. We developed logistic regression models of factors influencing sightability of mountain goat groups during helicopter surveys throughout the Cascades and Olympic Ranges in western Washington during summers, 20042007. We conducted 205 trials of the ability of aerial survey crews to detect groups of mountain goats whose presence was known based on simultaneous direct observation from the ground (n 84), Global Positioning System (GPS) telemetry (n 115), or both (n 6). Aerial survey crews detected 77 and 79 of all groups known to be present based on ground observers and GPS collars, respectively. The best models indicated that sightability of mountain goat groups was a function of the number of mountain goats in a group, presence of terrain obstruction, and extent of overstory vegetation. Aerial counts of mountain goats within groups did not differ greatly from known group sizes, indicating that under-counting bias within detected groups of mountain goats was small. We applied HorvitzThompson-like sightability adjustments to 1,139 groups of mountain goats observed in the Cascade and Olympic ranges, Washington, USA, from 2004 to 2007. Estimated mean sightability of individual animals was 85 but ranged 0.750.91 in areas with low and high sightability, respectively. Simulations of mountain goat surveys indicated that precision of population estimates adjusted for sightability biases increased with population size and number of replicate surveys, providing general guidance for the design of future surveys. Because survey conditions, group sizes, and habitat occupied by goats vary among surveys, we recommend using sightability correction methods to decrease bias in population estimates from aerial surveys of mountain goats.

Meta-image navigation augmenters for GPS denied mountain navigation of small UAS

NASA Astrophysics Data System (ADS)

Wang, Teng; ćelik, Koray; Somani, Arun K.

2014-06-01

We present a novel approach to use mountain drainage patterns for GPS-Denied navigation of small unmanned aerial systems (UAS) such as the ScanEagle, utilizing a down-looking fixed focus monocular imager. Our proposal allows extension of missions to GPS-denied mountain areas, with no assumption of human-made geographic objects. We leverage the analogy between mountain drainage patterns, human arteriograms, and human fingerprints, to match local drainage patterns to Graphics Processing Unit (GPU) rendered parallax occlusion maps of geo-registered radar returns (GRRR). Details of our actual GPU algorithm is beyond the subject of this paper, and is planned as a future paper. The matching occurs in real-time, while GRRR data is loaded on-board the aircraft pre-mission, so as not to require a scanning aperture radar during the mission. For recognition purposes, we represent a given mountain area with a set of spatially distributed mountain minutiae, i.e., details found in the drainage patterns, so that conventional minutiae-based fingerprint matching approaches can be used to match real-time camera image against template images in the training set. We use medical arteriography processing techniques to extract the patterns. The minutiae-based representation of mountains is achieved by first exposing mountain ridges and valleys with a series of filters and then extracting mountain minutiae from these ridges/valleys. Our results are experimentally validated on actual terrain data and show the effectiveness of minutiae-based mountain representation method. Furthermore, we study how to select landmarks for UAS navigation based on the proposed mountain representation and give a set of examples to show its feasibility. This research was in part funded by Rockwell Collins Inc.

Analysing wind farm efficiency on complex terrains

NASA Astrophysics Data System (ADS)

Castellani, Francesco; Astolfi, Davide; Terzi, Ludovico; Schaldemose Hansen, Kurt; Sanz Rodrigo, Javier

2014-06-01

Actual performances of onshore wind farms are deeply affected both by wake interactions and terrain complexity: therefore monitoring how the efficiency varies with the wind direction is a crucial task. Polar efficiency plot is therefore a useful tool for monitoring wind farm performances. The approach deserves careful discussion for onshore wind farms, where orography and layout commonly affect performance assessment. The present work deals with three modern wind farms, owned by Sorgenia Green, located on hilly terrains with slopes from gentle to rough. Further, onshore wind farm of Nprrekffir Enge has been analysed as a reference case: its layout is similar to offshore wind farms and the efficiency is mainly driven by wakes. It is shown and justified that terrain complexity imposes a novel and more consistent way for defining polar efficiency. Dependency of efficiency on wind direction, farm layout and orography is analysed and discussed. Effects of atmospheric stability have been also investigated through MERRA reanalysis data from NASA satellites. Monin-Obukhov Length has been used to discriminate climate regimes.

Topological Landscapes: A Terrain Metaphor for ScientificData

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weber, Gunther H.; Bremer, Peer-Timo; Pascucci, Valerio

2007-08-01

Scientific visualization and illustration tools are designed to help people understand the structure and complexity of scientific data with images that are as informative and intuitive as possible. In this context, the use of metaphors plays an important role, since they make complex information easily accessible by using commonly known concepts. In this paper we propose a new metaphor, called 'Topological Landscapes', which facilitates understanding the topological structure of scalar functions. The basic idea is to construct a terrain with the same topology as a given dataset and to display the terrain as an easily understood representation of the actualmore » input data. In this projection from an n-dimensional scalar function to a two-dimensional (2D) model we preserve function values of critical points, the persistence (function span) of topological features, and one possible additional metric property (in our examples volume). By displaying this topologically equivalent landscape together with the original data we harness the natural human proficiency in understanding terrain topography and make complex topological information easily accessible.« less

Linking aboveground net primary productivity to soil carbon and dissolved organic carbon in complex terrain

Treesearch

F.S. Peterson; K. Lajtha

2013-01-01

Factors influencing soil organic matter (SOM) stabilization and dissolved organic carbon (DOC) content in complex terrain, where vegetation, climate, and topography vary over the scale of a few meters, are not well understood. We examined the spatial correlations of lidar and geographic information system-derived landscape topography, empirically measured soil...

Constraining the Surface Energy Balance of Snow in Complex Terrain

NASA Astrophysics Data System (ADS)

Lapo, Karl E.

Physically-based snow models form the basis of our understanding of current and future water and energy cycles, especially in mountainous terrain. These models are poorly constrained and widely diverge from each other, demonstrating a poor understanding of the surface energy balance. This research aims to improve our understanding of the surface energy balance in regions of complex terrain by improving our confidence in existing observations and improving our knowledge of remotely sensed irradiances (Chapter 1), critically analyzing the representation of boundary layer physics within land models (Chapter 2), and utilizing relatively novel observations to in the diagnoses of model performance (Chapter 3). This research has improved the understanding of the literal and metaphorical boundary between the atmosphere and land surface. Solar irradiances are difficult to observe in regions of complex terrain, as observations are subject to harsh conditions not found in other environments. Quality control methods were developed to handle these unique conditions. These quality control methods facilitated an analysis of estimated solar irradiances over mountainous environments. Errors in the estimated solar irradiance are caused by misrepresenting the effect of clouds over regions of topography and regularly exceed the range of observational uncertainty (up to 80Wm -2) in all regions examined. Uncertainty in the solar irradiance estimates were especially pronounced when averaging over high-elevation basins, with monthly differences between estimates up to 80Wm-2. These findings can inform the selection of a method for estimating the solar irradiance and suggest several avenues of future research for improving existing methods. Further research probed the relationship between the land surface and atmosphere as it pertains to the stable boundary layers that commonly form over snow-covered surfaces. Stable conditions are difficult to represent, especially for low wind speed values and coupled land-atmosphere models have difficulty representing these processes. We developed a new method analyzing turbulent fluxes at the land surface that relies on using the observed surface temperature, which we called the offline turbulence method. We used this method to test a number of stability schemes as they are implemented within land models. Stability schemes can cause small biases in the simulated sensible heat flux, but these are caused by compensating errors, as no single method was able to accurately reproduce the observed distribution of the sensible heat flux. We described how these turbulence schemes perform within different turbulence regimes, particularly noting the difficulty representing turbulence during conditions with faster wind speeds and the transition between weak and strong wind turbulence regimes. Heterogeneity in the horizontal distribution of surface temperature associated with different land surface types likely explains some of the missing physics within land models and is manifested as counter-gradient fluxes in observations. The coupling of land and atmospheric models needs further attention, as we highlight processes that are missing. Expanding on the utility of surface temperature, Ts, in model evaluations, we demonstrated the utility of using surface temperature in snow models evaluations. Ts is the diagnostic variable of the modeled surface energy balance within physically-based models and is an ideal supplement to traditional evaluation techniques. We demonstrated how modeling decisions affect Ts, specifically testing the impact of vertical layer structure, thermal conductivity, and stability corrections in addition to the effect of uncertainty in forcing data on simulated Ts. The internal modeling decisions had minimal impacts relative to uncertainty in the forcing data. Uncertainty in downwelling longwave was found to have the largest impact on simulated Ts. Using Ts, we demonstrated how various errors in the forcing data can be identified, noting that uncertainty in downwelling longwave and wind are the easiest to identify due to their effect on night time minimum Ts.

Assessing the utility of passive microwave data for Snow Water Equivalent (SWE) estimation in the Sutlej River Basin of the northwestern Himalaya

NASA Astrophysics Data System (ADS)

Brandt, T.; Bookhagen, B.; Dozier, J.

2014-12-01

Since 1978, space based passive microwave (PM) radiometers have been used to comprehensively measure Snow Water Equivalent (SWE) on a global basis. The ability of PM radiometers to directly measure SWE at high temporal frequencies offers some distinct advantages over optical remote sensors. Nevertheless, in mountainous terrain PM radiometers often struggle to accurately measure SWE because of wet snow, saturation in deep snow, forests, depth hoar and stratigraphy, variable relief, and subpixel heterogeneity inherent in large pixel sizes. The Himalaya, because of their high elevation and high relief—much above tree line—offer an opportunity to examine PM products in the mountains without the added complication of trees. The upper Sutlej River basin— the third largest Himalayan catchment—lies in the western Himalaya. The river is a tributary of the Indus River and seasonal snow constitutes a substantial part of the basin's hydrologic budget. The basin has a few surface stations and river gauges, which is unique for the region. As such, the Sutlej River basin is a good location to analyze the accuracy and effectiveness of the current National Snow and Ice Data Center's (NSIDC) standard AMSR-E/Aqua Daily SWE product in mountainous terrain. So far, we have observed that individual pixels can "flicker", i.e. fluctuate from day to day, over large parts of the basin. We consider whether this is an artifact of the algorithm or whether this is embedded in the raw brightness temperatures themselves. In addition, we examine how well the standard product registers winter storms, and how it varies over heavily glaciated pixels. Finally, we use a few common measures of algorithm performance (precision, recall and accuracy) to test how well the standard product detects the presence of snow, using optical imagery for validation. An improved understanding of the effectiveness of PM imagery in the mountains will help to clarify the technology's limits.

Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal – A Systematic Synthesis of Literature

PubMed Central

Dhimal, Meghnath; Ahrens, Bodo; Kuch, Ulrich

2015-01-01

Background Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change. Methodology A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines. Principal Findings We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies. Conclusion Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant. PMID:26086887

Convective initiation in the vicinity of the subtropical Andes

NASA Astrophysics Data System (ADS)

Rasmussen, K. L.; Houze, R.

2014-12-01

Extreme convection tends to form in the vicinity of mountain ranges, and the Andes in subtropical South America help spawn some of the most intense convection in the world. An investigation of the most intense storms for 11 years of TRMM Precipitation Radar (PR) data shows a tendency for squall lines to initiate and develop in this region with the canonical leading convective line/trailing stratiform structure. The synoptic environment and structures of the extreme convection and MCSs in subtropical South America are similar to those found in other regions of the world, especially the United States. In subtropical South America, however, the topographical influence on the convective initiation and maintenance of the MCSs is unique. A capping inversion in the lee of the Andes is important in preventing premature triggering. The Andes and other mountainous terrain of Argentina focus deep convective initiation in a narrow region. Subsequent to initiation, the convection often evolves into propagating mesoscale convective systems similar to those seen over the Great Plains of the U. S. and produces damaging tornadoes, hail, and floods across a wide agricultural region. Numerical simulations conducted with the NCAR Weather Research and Forecasting (WRF) Model extend the observational analysis and provide an objective evaluation of storm initiation, terrain effects, and development mechanisms. The simulated mesoscale systems closely resemble the storm structures seen by the TRMM Precipitation Radar as well as the overall shape and character of the storms shown in GOES satellite data. A sensitivity experiment with different configurations of topography, including both decreasing and increasing the height of the Andes Mountains, provides insight into the significant influence of orography in focusing convective initiation in this region. Lee cyclogenesis and a strong low-level jet are modulated by the height of the Andes Mountains and directly affect the character, intensity, and spatial distribution of the convective systems. A new conceptual model for convective initiation in subtropical South America that integrates the results of the topographic sensitivity experiments will be presented.

Interactions between Shrubs and Permafrost in the Torngat Mountains, Northern Labrador, Canada

NASA Astrophysics Data System (ADS)

Lewkowicz, A.; Way, R. G.; Hermanutz, L.; Trant, A.; Siegwart Collier, L.; Whitaker, D.

2017-12-01

Discontinuous permafrost is acutely sensitive to climate warming and vegetation dynamics. Shrub height is positively correlated with accumulation of snow in the tundra resulting in warming of the ground in winter, and greater shading and lower surface temperatures in summer. Rapid greening due to climate warming has been observed throughout northeastern Canada and particularly in the coastal mountainous terrain of the Torngat Mountains National Park. Our research examines how this shrubification in the Torngat Mountains is modifying permafrost characteristics using observations which extend over a 100 km south-north transect from the sporadic zone (Saglek, Torr Bay) to where permafrost is widespread (Nakvak Brook, Kangalaksiorvik Lake) and potentially continuous (Komaktorvik River). We use air and ground temperature monitoring, vegetation surveys, dendrochronology, frost probing and electrical resistivity tomography (ERT) to describe the complex interactions between shrub growth, geomorphology, climate and permafrost in a region where climate warming is rapidly altering the landscape. Preliminary analysis of field data shows low resistivity anomalies in the ERT profiles at some sites with thin permafrost, interpreted as unfrozen zones correlated with areas of tall shrubs (Alnus spp., Salix spp. and Betula glandulosa; ranging from prostrate to 2 m). Elsewhere, high resistivities extend to the base of the ERT profiles, indicating thicker permafrost, and no obvious impact of medium to low-prostrate shrubs (Salix spp., Betula glandulosa, Rhododendron spp., and Vaccinium spp.; up to 50 cm). Permafrost is interpreted to be present at most sites with low or prostrate shrubs, except where hydrological conditions favour warmer ground temperatures. We infer that the net impact of increasing shrub heights on the active layer and permafrost depends on antecedent ground temperatures and surficial geology. Increasing shrub heights may cause permafrost degradation at sites where mean ground temperatures are close to 0°C and rising due to climate warming. A deeper active layer or loss of permafrost in turn could affect hydrological conditions, potentially influencing shrub size and species composition.

Toward Reducing Uncertainties in Biospheric Carbon Uptake in the American West: An Atmospheric Perspective

NASA Astrophysics Data System (ADS)

Lin, J. C.; Stephens, B. B.; Mallia, D.; Wu, D.; Jacobson, A. R.

2015-12-01

Despite the need for an understanding of terrestrial biospheric carbon fluxes to account for carbon cycle feedbacks and predict future CO2 concentrations, knowledge of such fluxes at the regional scale remains poor. This is particularly true in mountainous areas, where lack of observations combined with difficulties in their interpretation lead to significant uncertainties. Yet mountainous regions are also where significant forest cover and biomass are found—areas that have the potential to serve as carbon sinks. In particular, understanding carbon fluxes in the American West is of critical importance for the U.S. carbon budget, as the large area and biomass indicate potential for carbon sequestration. However, disturbances such as drought, insect outbreak, and wildfires in this region can introduce significant perturbations to the carbon cycle and thereby affect the amount of carbon sequestered by vegetation in the Rockies. To date, there have been few atmospheric CO2 observations in the American Rockies due to a combination of difficulties associated with logistics and interpretation of the measurements in the midst of complex terrain. Among the few sites are those associated with NCAR's Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON). As CO2 observations in mountainous areas increase in the future, it is imperative that they can be properly interpreted to yield information about biospheric carbon fluxes. In this paper, we will present CO2 observations from RACCOON, along with atmospheric simulations that attempt to extract information about biospheric carbon fluxes in the Western U.S. from these observations. We show that atmospheric models can significantly misinterpret the CO2 observations, leading to large errors in the retrieved biospheric fluxes, due to erroneous atmospheric flows. Recommendations for ways to minimize such errors and properly link the CO2 concentrations to biospheric fluxes are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joe, Paul; Scott, Bill; Doyle, Chris

Abstract—An innovative monitoring network was implemented to support the operational and science programs for the Vancouver 2010 Winter Olympics. It consisted of in situ weather stations on custom-designed platforms. The sensors included an HMP45C for temperature, humidity and pressure, a tipping bucket rain gauge, an acoustic snow depth sensor, a Pluvio 1 precipitation gauge and an anemometer placed at gauge height and at 10 m height. Modifications to commercial automated precipitation gauges were necessary for the heavy snowfall conditions. Advanced or emerging technologies were deployed to support scientific and nowcasting studies into precipitation intensity, typing, visibility and wind. The sensorsmore » included an FD12P visibility and precipitation sensor, a precipitation occurrence sensing system (POSS) present weather sensor, a Hotplate precipitation sensor and a Parsivel disdrometer. Data were collected at 1 min sampling intervals. A Doppler weather radar was deployed in a valley location and provided critical detailed low-level data. An X-band dual-polarized radar was deployed by the National Oceanic and Atmospheric Administration to monitor Vancouver and Cypress Mountain. Three remote sensing stations for vertical profiling were established. At the base of Whistler Mountain, a micro-rain radar, a 22-channel radiometer, a ceilometer, a Parsivel and a POSS were installed. At the base of Cypress Mountain, a micro-rain radar, a ceilometer, a low cost rain sensor (LCR by ATTEX) and a POSS were installed. At Squamish, a wind profiler and a POSS were installed. Weather sensors were mounted on the Whistler Village Gondola and on the Peak to Peak gondola. Sites were established along the Whistler Mountain slope and at other key locations. The combination of sites and instruments formed a comprehensive network to provide observations appropriate for nowcasting in winter complex terrain and investigate precipitation, visibility and wind processes. The contribution provides a detailed description of the network, their sensors, the innovations and some examples.« less

Interactions between Shrubs and Permafrost in the Torngat Mountains, Northern Labrador, Canada

NASA Astrophysics Data System (ADS)

Lewkowicz, A.; Way, R. G.; Hermanutz, L.; Trant, A.; Siegwart Collier, L.; Whitaker, D.

2016-12-01

Discontinuous permafrost is acutely sensitive to climate warming and vegetation dynamics. Shrub height is positively correlated with accumulation of snow in the tundra resulting in warming of the ground in winter, and greater shading and lower surface temperatures in summer. Rapid greening due to climate warming has been observed throughout northeastern Canada and particularly in the coastal mountainous terrain of the Torngat Mountains National Park. Our research examines how this shrubification in the Torngat Mountains is modifying permafrost characteristics using observations which extend over a 100 km south-north transect from the sporadic zone (Saglek, Torr Bay) to where permafrost is widespread (Nakvak Brook, Kangalaksiorvik Lake) and potentially continuous (Komaktorvik River). We use air and ground temperature monitoring, vegetation surveys, dendrochronology, frost probing and electrical resistivity tomography (ERT) to describe the complex interactions between shrub growth, geomorphology, climate and permafrost in a region where climate warming is rapidly altering the landscape. Preliminary analysis of field data shows low resistivity anomalies in the ERT profiles at some sites with thin permafrost, interpreted as unfrozen zones correlated with areas of tall shrubs (Alnus spp., Salix spp. and Betula glandulosa; ranging from prostrate to 2 m). Elsewhere, high resistivities extend to the base of the ERT profiles, indicating thicker permafrost, and no obvious impact of medium to low-prostrate shrubs (Salix spp., Betula glandulosa, Rhododendron spp., and Vaccinium spp.; up to 50 cm). Permafrost is interpreted to be present at most sites with low or prostrate shrubs, except where hydrological conditions favour warmer ground temperatures. We infer that the net impact of increasing shrub heights on the active layer and permafrost depends on antecedent ground temperatures and surficial geology. Increasing shrub heights may cause permafrost degradation at sites where mean ground temperatures are close to 0°C and rising due to climate warming. A deeper active layer or loss of permafrost in turn could affect hydrological conditions, potentially influencing shrub size and species composition.

Mars: Fretted and chaotic terrains

NASA Technical Reports Server (NTRS)

Sharp, R. P.

1973-01-01

Fretted Martian terrain is characterized by smooth, flat, lowland areas separated from a cratered upland by abrupt escarpments of complex planimetric configuration and a maximum estimated height approaching 1 to 2 km. It is the product of some unusual erosive or abstractive process that has created steep escarpments. Chaotic terrain differs from fretted terrain in having a rough floor topography featuring a haphazard jumble of large angular blocks, and by arc-shaped slump blocks on its bounding escarpments. Its existence has now been confirmed by Mariner 9 pictures, and the characteristics, location, and areal extent of chaotic terrain have been more accurately and completely defined.

Formation of a katabatic induced cold front at the east Andean slopes

NASA Astrophysics Data System (ADS)

Trachte, K.; Nauss, T.,; Rollenbeck, R.; Bendix, J.

2009-04-01

Within the DFG research unit 816, climate dynamics in a tropical mountain rain forest in the national reserve of the Reserva Biósfera de San Francisco in South Ecuador are investigated. Precipitation measurements in the mountain environment of the Estación Científica de San Francisco (ECSF) with a vertical rain radar profiler have been made over the last seven years. They reveal unexpected constant early morning rainfall events. On the basis of cloud top temperatures from corresponding GOES satellite imageries, a Mesoscale Convective System could be derived. Its formation region is located south-east of the ECSF in the Peruvian Amazon basin. The generation of the MCS is assumed to results from an interaction of both local and mesoscale conditions. Nocturnal drainage air from the Andean slopes and valleys confluences in the Amazon basin due to the concave lined terrain. This cold air converges with the warm-moist air of the Amazon inducing a local cold front. This process yields to deep convection resulting in a MCS. With the numerical model ARPS the hypothesized formation of a cloud cluster due to a katabatic induced cold front is shown in an ideal case study. Therefor an ideal terrain model representing the features of the Andes in the target area has been used. The simplification of the oprography concerns a concave lined slope and a valley draining into the basin. It describes the confluence of the cold drainage air due to the shape of the terrain. Inside the basin the generation of a local cold front is shown, which triggers the formation of a cloud cluster.

High-resolution regional gravity field modelling in a mountainous area from terrestrial gravity data

NASA Astrophysics Data System (ADS)

Bucha, Blažej; Janák, Juraj; Papčo, Juraj; Bezděk, Aleš

2016-11-01

We develop a high-resolution regional gravity field model by a combination of spherical harmonics, band-limited spherical radial basis functions (SRBFs) and the residual terrain model (RTM) technique. As the main input data set, we employ a dense terrestrial gravity database (3-6 stations km-2), which enables gravity field modelling up to very short spatial scales. The approach is based on the remove-compute-restore methodology in which all the parts of the signal that can be modelled are removed prior to the least-squares adjustment in order to smooth the input gravity data. To this end, we utilize degree-2159 spherical harmonic models and the RTM technique using topographic models at 2 arcsec resolution. The residual short-scale gravity signal is modelled via the band-limited Shannon SRBF expanded up to degree 21 600, which corresponds to a spatial resolution of 30 arcsec. The combined model is validated against GNSS/levelling-based height anomalies, independent surface gravity data, deflections of the vertical and terrestrial vertical gravity gradients achieving an accuracy of 2.7 cm, 0.53 mGal, 0.39 arcsec and 279 E in terms of the RMS error, respectively. A key aspect of the combined approach, especially in mountainous areas, is the quality of the RTM. We therefore compare the performance of two RTM techniques within the innermost zone, the tesseroids and the polyhedron. It is shown that the polyhedron-based approach should be preferred in rugged terrain if a high-quality RTM is required. In addition, we deal with the RTM computations at points located below the reference surface of the residual terrain which is known to be a rather delicate issue.

A framework for WRF to WRF-IBM grid nesting to enable multiscale simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiersema, David John; Lundquist, Katherine A.; Chow, Fotini Katapodes

With advances in computational power, mesoscale models, such as the Weather Research and Forecasting (WRF) model, are often pushed to higher resolutions. As the model’s horizontal resolution is refined, the maximum resolved terrain slope will increase. Because WRF uses a terrain-following coordinate, this increase in resolved terrain slopes introduces additional grid skewness. At high resolutions and over complex terrain, this grid skewness can introduce large numerical errors that require methods, such as the immersed boundary method, to keep the model accurate and stable. Our implementation of the immersed boundary method in the WRF model, WRF-IBM, has proven effective at microscalemore » simulations over complex terrain. WRF-IBM uses a non-conforming grid that extends beneath the model’s terrain. Boundary conditions at the immersed boundary, the terrain, are enforced by introducing a body force term to the governing equations at points directly beneath the immersed boundary. Nesting between a WRF parent grid and a WRF-IBM child grid requires a new framework for initialization and forcing of the child WRF-IBM grid. This framework will enable concurrent multi-scale simulations within the WRF model, improving the accuracy of high-resolution simulations and enabling simulations across a wide range of scales.« less

Metabolic Costs of Military Load Carriage over Complex Terrain.

PubMed

Looney, David P; Santee, William R; Karis, Anthony J; Blanchard, Laurie A; Rome, Maxwell N; Carter, Alyssa J; Potter, Adam W

2018-05-31

Dismounted military operations often involve prolonged load carriage over complex terrain, which can result in excessive metabolic costs that can directly impair soldiers' performance. Although estimating these demands is a critical interest for mission planning purposes, it is unclear whether existing estimation equations developed from controlled laboratory- and field-based studies accurately account for energy costs of traveling over complex terrain. This study investigated the accuracy of the following equations for military populations when applied to data collected over complex terrain with two different levels of load carriage: American College of Sports Medicine (2002), Givoni and Goldman (1971), Jobe and White (2009), Minetti et al (2002), Pandolf et al (1977), and Santee et al (2003). Nine active duty military personnel (age 21 ± 3 yr; height 1.72 ± 0.07 m; body mass 83.4 ± 12.9 kg; VO2 max 47.8 ± 3.9 mL/kg/min) were monitored during load carriage (with loads equal to 30% and 45% of body mass) over a 10-km mixed terrain course on two separate test days. The course was divided into four 2.5-km laps of 40 segments based on distance, grade, and/or surface factors. Timing gates and radio-frequency identification cards (SportIdent; Scarborough Orienteering, Huntington Beach, CA) were used to record completion times for each course segment. Breath-by-breath measures of energy expenditure were collected using portable oxygen exchange devices (COSMED Sri., Rome, Italy) and compared model estimates. The Santee et al equation performed best, demonstrating the smallest estimation bias (-13 ± 87 W) and lowest root mean square error (99 W). Current predictive equations underestimate the metabolic cost of load carriage by military personnel over complex terrain. Applying the Santee et al correction factor to the Pandolf et al equation may be the most suitable approach for estimating metabolic demands in these circumstances. However, this work also outlines the need for improvements to these methods, new method development and validation, or the use of a multi-model approach to account for mixed terrain.

Piloted Simulation of Various Synthetic Vision Systems Terrain Portrayal and Guidance Symbology Concepts for Low Altitude En-Route Scenario

NASA Technical Reports Server (NTRS)

Takallu, M. A.; Glaab, L. J.; Hughes, M. F.; Wong, D. T.; Bartolone, A. P.

2008-01-01

In support of the NASA Aviation Safety Program's Synthetic Vision Systems Project, a series of piloted simulations were conducted to explore and quantify the relationship between candidate Terrain Portrayal Concepts and Guidance Symbology Concepts, specific to General Aviation. The experiment scenario was based on a low altitude en route flight in Instrument Metrological Conditions in the central mountains of Alaska. A total of 18 general aviation pilots, with three levels of pilot experience, evaluated a test matrix of four terrain portrayal concepts and six guidance symbology concepts. Quantitative measures included various pilot/aircraft performance data, flight technical errors and flight control inputs. The qualitative measures included pilot comments and pilot responses to the structured questionnaires such as perceived workload, subjective situation awareness, pilot preferences, and the rare event recognition. There were statistically significant effects found from guidance symbology concepts and terrain portrayal concepts but no significant interactions between them. Lower flight technical errors and increased situation awareness were achieved using Synthetic Vision Systems displays, as compared to the baseline Pitch/Roll Flight Director and Blue Sky Brown Ground combination. Overall, those guidance symbology concepts that have both path based guidance cue and tunnel display performed better than the other guidance concepts.

Bayes classification of interferometric TOPSAR data

NASA Technical Reports Server (NTRS)

Michel, T. R.; Rodriguez, E.; Houshmand, B.; Carande, R.

1995-01-01

We report the Bayes classification of terrain types at different sites using airborne interferometric synthetic aperture radar (INSAR) data. A Gaussian maximum likelihood classifier was applied on multidimensional observations derived from the SAR intensity, the terrain elevation model, and the magnitude of the interferometric correlation. Training sets for forested, urban, agricultural, or bare areas were obtained either by selecting samples with known ground truth, or by k-means clustering of random sets of samples uniformly distributed across all sites, and subsequent assignments of these clusters using ground truth. The accuracy of the classifier was used to optimize the discriminating efficiency of the set of features that was chosen. The most important features include the SAR intensity, a canopy penetration depth model, and the terrain slope. We demonstrate the classifier's performance across sites using a unique set of training classes for the four main terrain categories. The scenes examined include San Francisco (CA) (predominantly urban and water), Mount Adams (WA) (forested with clear cuts), Pasadena (CA) (urban with mountains), and Antioch Hills (CA) (water, swamps, fields). Issues related to the effects of image calibration and the robustness of the classification to calibration errors are explored. The relative performance of single polarization Interferometric data classification is contrasted against classification schemes based on polarimetric SAR data.

Feasibility of using S-191 infrared spectra for geological studies from space

NASA Technical Reports Server (NTRS)

Lyon, R. J. P.

1976-01-01

Use of the S-191 spectrometer system aboard the SKYLAB(SL3) mission shows that geologically meaningful spectra can be extracted from the data by which terrain target can be differentiated. The Si-O bond in all silicates (which form most surface rocks) produced an emission minimum which is characteristic of a mineral, or a set of minerals, in a rock. The underflight RB57 mission was far more successful, primarily because of its much slower velocity allowing a higher signal/noise, and hence better spectral resolution for any given area terrain. With the RB57 spectra, areas can be differentiated and significant differences in rock targets demonstrated. The geological provenance of some alluvial outwash in the nearby mountains over which the aircraft also flew its flight strip can be indicated.

Preliminary geological mapping of Io

NASA Technical Reports Server (NTRS)

Masursky, H.; Schaber, G. G.; Soderblom, L. A.; Strom, R. G.

1979-01-01

A preliminary summary of information gained by Voyager 1 on the colored, terrain and landform surface units of Io and their global distribution is presented. Colored units are classified as white to bluish-white regions which may be sulfur or sulfur dioxide deposits, red, orange, or yellow regions thought to contain various sublimates or alterations of sulfur, brownish regions limited to the polar areas and dark brown areas surrounding some vents. Terrain features observed include plains broken by scarps, isolated mountainous regions and volcanic vents resembling terrestrial caldera or pit craters. Maps of the distribution of these features, compiled by photogeological mapping techniques developed for terrestrial volcanic mapping, are presented, and the implications of the surface unit distributions for the volcanology, crustal composition, internal convection patterns and surface age of Io are discussed.

Shortwave radiation parameterization scheme for subgrid topography

NASA Astrophysics Data System (ADS)

Helbig, N.; LöWe, H.

2012-02-01

Topography is well known to alter the shortwave radiation balance at the surface. A detailed radiation balance is therefore required in mountainous terrain. In order to maintain the computational performance of large-scale models while at the same time increasing grid resolutions, subgrid parameterizations are gaining more importance. A complete radiation parameterization scheme for subgrid topography accounting for shading, limited sky view, and terrain reflections is presented. Each radiative flux is parameterized individually as a function of sky view factor, slope and sun elevation angle, and albedo. We validated the parameterization with domain-averaged values computed from a distributed radiation model which includes a detailed shortwave radiation balance. Furthermore, we quantify the individual topographic impacts on the shortwave radiation balance. Rather than using a limited set of real topographies we used a large ensemble of simulated topographies with a wide range of typical terrain characteristics to study all topographic influences on the radiation balance. To this end slopes and partial derivatives of seven real topographies from Switzerland and the United States were analyzed and Gaussian statistics were found to best approximate real topographies. Parameterized direct beam radiation presented previously compared well with modeled values over the entire range of slope angles. The approximation of multiple, anisotropic terrain reflections with single, isotropic terrain reflections was confirmed as long as domain-averaged values are considered. The validation of all parameterized radiative fluxes showed that it is indeed not necessary to compute subgrid fluxes in order to account for all topographic influences in large grid sizes.

Measurements of car-body lateral vibration induced by high-speed trains negotiating complex terrain sections under strong wind conditions

NASA Astrophysics Data System (ADS)

Liu, Dongrun; Lu, Zhaijun; Zhong, Mu; Cao, Tianpei; Chen, Dong; Xiong, Yupu

2018-02-01

Assessment of the vibration of high-speed trains negotiating complex sections of terrain under strong wind conditions is very important for research into the operation safety and comfort of passengers on high-speed trains. To assess the vibration of high-speed trains negotiating complex sections of terrain under strong wind conditions, we performed a field measurement when the train passes through typical sections of complex terrain along the Lanzhou-Xinjiang high-speed railway in China. We selected the lateral vibration conditions, including the roll angle and lateral displacement of car-body gravity centre through two typical representative sections (embankment-tunnel-embankment and embankment-rectangular transition-cutting) for analysis. The results show that the severe car-swaying phenomenon occurs when the high-speed train moves through the test section, and the car-body lateral vibration characteristic is related significantly to the state of the terrain and topography along the railway. The main causes for this car-swaying phenomenon may be the transitions between different windproof structures, and the greater the scale of the transition region between different windproof structures or landform changes, the more obvious the car-swaying phenomenon becomes. The lateral vibration of the car-body is relatively steady when the train is running through terrain with minor changes in topography, such as the windbreak installed on the bridge and embankment, but the tail car sways more violently than the head car. When the vehicle runs from the windbreak installed on the embankment into the tunnel (or in the opposite direction), the tail car sways more intensely than the head car, and the head car runs relatively stable in the tunnel.

Applications of a stump-to-mill computer model to cable logging planning

Treesearch

Chris B. LeDoux

1986-01-01

Logging cost simulators and data from logging cost studies have been assembled and converted into a series of simple equations that can be used to estimate the stump-to-mill cost of cable logging in mountainous terrain of the Eastern United States. These equations are based on the use of two small and four medium-sized cable yarders and are applicable for harvests of...

Mountain Warfare and Cold Weather Operations

DTIC Science & Technology

2016-04-29

military purposes, cold regions are defined as any region where cold temperatures , unique terrain, and snowfall have a significant effect on military...because of the wind’s effect on the body’s perceived temperature . Wet cold leads to hypothermia, frost bite, and trench foot. Wet cold conditions are...combined cooling effect of ambient temperature and wind (wind chill) experienced by their troops (see Figure 1-5). The Environment ATP 3-90.97

Airpower in Mountains

DTIC Science & Technology

2012-06-01

Soviet Union to the most recent operations of the United States. The British presence in the region dates back to the nineteenth century. The British...lost several dozen men. Maj N. G. Ten’kov Introduction The Soviet Union occupied Afghanistan for nine years from the end of 1979 to 1989...terrain, transport aircraft flew in supplies from the Soviet Union , as well as missions to supply isolated posts and surrounded garrisons.26 They

Fires in South Africa, snow in Lesotho

NASA Technical Reports Server (NTRS)

2002-01-01

The precipitation that brought snow fall to the Drakensberg Mountains in Lesotho in southern Africa was not enough to quench the numerous fires (marked with red dots) burning throughout the Republic of South Africa. These Moderate Resolution Imaging Spectroradiometer (MODIS) images from June 18, 2002, and July 2, 2002, show the snowfall in landlocked Lesotho contrasting sharply with the country's brown, mountainous terrain. (In the false-color image, vegetation is bright green, bare soil is brown, and burned areas are reddish-brown. In northeast Republic of South Africa, right along the border with Mozambique, the smooth, gray-brown terrain shows the boundaries of Kruger National Park. The Park was established in the late 1800s to protect game species, such as elephants, antelope, and bison, which were being hunted in great numbers. In this image, dark brown patches reveal the location of previous fires. The vegetation has yet to come back, and the landscape is virtually bare. NASA scientists study fire behavior in Kruger as part of the SAFARI field campaign. Running southward through Mozambique and into the Indian Ocean is the muddy Limpopo River--known to many through Rudyard Kipling's 'Just-so' story about how the elephant got its trunk. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

High-resolution digital elevation models from single-pass TanDEM-X interferometry over mountainous regions: A case study of Inylchek Glacier, Central Asia

NASA Astrophysics Data System (ADS)

Neelmeijer, Julia; Motagh, Mahdi; Bookhagen, Bodo

2017-08-01

This study demonstrates the potential of using single-pass TanDEM-X (TDX) radar imagery to analyse inter- and intra-annual glacier changes in mountainous terrain. Based on SAR images acquired in February 2012, March 2013 and November 2013 over the Inylchek Glacier, Kyrgyzstan, we discuss in detail the processing steps required to generate three reliable digital elevation models (DEMs) with a spatial resolution of 10 m that can be used for glacial mass balance studies. We describe the interferometric processing steps and the influence of a priori elevation information that is required to model long-wavelength topographic effects. We also focus on DEM alignment to allow optimal DEM comparisons and on the effects of radar signal penetration on ice and snow surface elevations. We finally compare glacier elevation changes between the three TDX DEMs and the C-band shuttle radar topography mission (SRTM) DEM from February 2000. We introduce a new approach for glacier elevation change calculations that depends on the elevation and slope of the terrain. We highlight the superior quality of the TDX DEMs compared to the SRTM DEM, describe remaining DEM uncertainties and discuss the limitations that arise due to the side-looking nature of the radar sensor.

Global Topography of Titan from Cassini RADAR Data (Invited)

NASA Astrophysics Data System (ADS)

Lorenz, R. D.; Cassini RADAR Team

2010-12-01

Cassini RADAR data are used to construct a global, albeit sparsely-sampled, topography map, and to generate a hypsometric profile to compare with other planetary bodies. Titan’s hypsogram is unimodal and strikingly narrow compared with the terrestrial planets. To investigate topographic extremes, a novel variant on the classic hypsogram is introduced, with a logarithmic abscissa to highlight mountainous terrain. In such a plot, the top of the terrestrial hypsogram is quite distinct from those of Mars and Venus due to the ‘glacial buzz-saw’ that clips terrestrial topography above the snowline. In contrast to the positive skew seen in other hypsograms, with a long tail of positive relief due to mountains, there is an indication (weak, given the limited data for Titan so far) that the Titan hypsogram appears slightly negatively skewed, suggesting a significant population of unfilled depressions. Limited data permit only a simplistic comparison of Titan topography with other icy satellites but we find that the standard deviation of terrain height (albeit at different scales) is similar to those of Ganymede and Europa. The topography of terrestrial planets is sampled with the same coverage that we have for Titan to gauge what as-yet-undiscovered topographic surprises may yet be hidden by Titan’s haze.

KRISSY: user's guide to modeling three-dimensional wind flow in complex terrain

Treesearch

Michael A. Fosberg; Michael L. Sestak

1986-01-01

KRISSY is a computer model for generating three-dimensional wind flows in complex terrain from data that were not or perhaps cannot be collected. The model is written in FORTRAN IV This guide describes data requirements, modeling, and output from an applications viewpoint rather than that of programming or theoretical modeling. KRISSY is designed to minimize...

Geologic map of the Providence Mountains in parts of the Fountain Peak and adjacent 7.5' quadrangles, San Bernardino County, California

USGS Publications Warehouse

Stone, Paul; Miller, David M.; Stevens, Calvin H.; Rosario, Jose J.; Vazquez, Jorge A.; Wan, Elmira; Priest, Susan S.; Valin, Zenon C.

2017-03-22

IntroductionThe Providence Mountains are in the eastern Mojave Desert about 60 km southeast of Baker, San Bernardino County, California. This range, which is noted for its prominent cliffs of Paleozoic limestone, is part of a northeast-trending belt of mountainous terrain more than 100 km long that also includes the Granite Mountains, Mid Hills, and New York Mountains. Providence Mountains State Recreation Area encompasses part of the range, the remainder of which is within Mojave National Preserve, a large parcel of land administered by the National Park Service. Access to the Providence Mountains is by secondary roads leading south and north from Interstate Highways 15 and 40, respectively, which bound the main part of Mojave National Preserve.The geologic map presented here includes most of Providence Mountains State Recreation Area and land that surrounds it on the north, west, and south. This area covers most of the Fountain Peak 7.5′ quadrangle and small adjacent parts of the Hayden quadrangle to the north, the Columbia Mountain quadrangle to the northeast, and the Colton Well quadrangle to the east. The map area includes representative outcrops of most of the major geologic elements of the Providence Mountains, including gneissic Paleoproterozoic basement rocks, a thick overlying sequence of Neoproterozoic to Triassic sedimentary rocks, Jurassic rhyolite that intrudes and overlies the sedimentary rocks, Jurassic plutons and associated dikes, Miocene volcanic rocks, and a variety of Quaternary surficial deposits derived from local bedrock units. The purpose of the project was to map the area in detail, with primary emphasis on the pre-Quaternary units, to provide an improved stratigraphic, structural, and geochronologic framework for use in land management applications and scientific research.

[Study on extraction method of Panax notoginseng plots in Wenshan of Yunnan province based on decision tree model].

PubMed

Shi, Ting-Ting; Zhang, Xiao-Bo; Guo, Lan-Ping; Huang, Lu-Qi

2017-11-01

The herbs used as the material for traditional Chinese medicine are always planted in the mountainous area where the natural environment is suitable. As the mountain terrain is complex and the distribution of planting plots is scattered, the traditional survey method is difficult to obtain accurate planting area. It is of great significance to provide decision support for the conservation and utilization of traditional Chinese medicine resources by studying the method of extraction of Chinese herbal medicine planting area based on remote sensing and realizing the dynamic monitoring and reserve estimation of Chinese herbal medicines. In this paper, taking the Panax notoginseng plots in Wenshan prefecture of Yunnan province as an example, the China-made GF-1multispectral remote sensing images with a 16 m×16 m resolution were obtained. Then, the time series that can reflect the difference of spectrum of P. notoginseng shed and the background objects were selected to the maximum extent, and the decision tree model of extraction the of P. notoginseng plots was constructed according to the spectral characteristics of the surface features. The results showed that the remote sensing classification method based on the decision tree model could extract P. notoginseng plots in the study area effectively. The method can provide technical support for extraction of P. notoginseng plots at county level. Copyright© by the Chinese Pharmaceutical Association.

Distribution and Variability of Satellite-Derived Signals of Isolated Convection Initiation Events Over Central Eastern China

NASA Astrophysics Data System (ADS)

Huang, Yipeng; Meng, Zhiyong; Li, Jing; Li, Wanbiao; Bai, Lanqiang; Zhang, Murong; Wang, Xi

2017-11-01

This study combined measurements from the Chinese operational geostationary satellite Fengyun-2E (FY-2E) and ground-based weather radars to conduct a statistical survey of isolated convection initiation (CI) over central eastern China (CEC). The convective environment in CEC is modulated by the complex topography and monsoon climate. From May to August 2010, a total of 1,630 isolated CI signals were derived from FY-2E using a semiautomated method. The formation of these satellite-derived CI signals peaks in the early afternoon and occurs with high frequency in areas with remarkable terrain inhomogeneity (e.g., mountain, water, and mountain-water areas). The high signal frequency areas shift from northwest CEC (dry, high altitude) in early summer to southeast CEC (humid, low altitude) in midsummer along with an increasing monthly mean frequency. The satellite-derived CI signals tend to have longer lead times (the time difference between satellite-derived signal formation and radar-based CI) in the late morning and afternoon than in the early morning and night. During the early morning and night, the distinction between cloud top signatures and background terrestrial radiation becomes less apparent, resulting in delayed identification of the signals and thus short and even negative lead times. A decline in the lead time is observed from May to August, likely due to the increasing cloud growth rate and warm-rain processes. Results show increasing lead times with increasing landscape elevation, likely due to more warm-rain processes over the coastal sea and plain, along with a decreasing cloud growth rate from hill and mountain to the plateau.

Quantifying the changes in the High Mountain Asia snow hydrology

NASA Astrophysics Data System (ADS)

Yoon, Y.; Kumar, S.; Mocko, D. M.; Rosenberg, R. I.; Kwon, Y.; Forman, B. A.; Zaitchik, B. F.

2017-12-01

The melting of snow and glaciers in the High Mountain Asia (HMA) provides the water needs of approximately 1.3 billion people in the region. Increasing temperatures have large effects on the hydrologic cycle, influencing snowmelt, snowpack, stream flow, and water runoff, which can impact all aspects of water security, such as water allocation, conservation, efficiency and land-use planning. Most mountain regions, however, remain ungauged without in-situ measurement of precipitation or snowpack due to the complex terrain, and thus it is difficult to understand the regional water balance and assess how it might change in the future. In this study, we focus on characterizing the spatiotemporal patterns of snowpack states and fluxes over the last 30+ years (1980 - present) and assessing the relationship between snowmelt and runoff. The Noah land surface model with multi-parameterization options, version 3.6 (Noah-MP.3.6) in the NASA Land Information System (LIS) is used to establish a high resolution (1 km) modeling environment over the HMA. Combining information from satellite observations and the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) is used to provide an effective way to develop spatially and temporally continuous estimates of changes. To improve the spatial representativeness of the precipitation field for modeling at 1km resolution, the input field is downscaled using a stochastic downscaling method with the monthly WorldClim data. The other meteorological inputs (e.g., air temperature, humidity, pressure, wind, and downward shortwave and longwave) are corrected for elevation through lapse-rate and slope-aspect methods. Evaluation of the model estimates is presented using satellite-derived data (e.g., MODIS and GRACE) and reanalysis products (e.g., CMC and ERA-interim).

Snow cover distribution over elevation zones in a mountainous catchment

NASA Astrophysics Data System (ADS)

Panagoulia, D.; Panagopoulos, Y.

2009-04-01

A good understanding of the elevetional distribution of snow cover is necessary to predict the timing and volume of runoff. In a complex mountainous terrain the snow cover distribution within a watershed is highly variable in time and space and is dependent on elevation, slope, aspect, vegetation type, surface roughness, radiation load, and energy exchange at the snow-air interface. Decreases in snowpack due to climate change could disrupt the downstream urban and agricultural water supplies, while increases could lead to seasonal flooding. Solar and longwave radiation are dominant energy inputs driving the ablation process. Turbulent energy exchange at the snow cover surface is important during the snow season. The evaporation of blowing and drifting snow is strongly dependent upon wind speed. Much of the spatial heterogeneity of snow cover is the result of snow redistribution by wind. Elevation is important in determining temperature and precipitation gradients along hillslopes, while the temperature gradients determine where precipitation falls as rain and snow and contribute to variable melt rates within the hillslope. Under these premises, the snow accumulation and ablation (SAA) model of the US National Weather Service (US NWS) was applied to implement the snow cover extent over elevation zones of a mountainous catchment (the Mesochora catchment in Western-Central Greece), taking also into account the indirectly included processes of sublimation, interception, and snow redistribution. The catchment hydrology is controlled by snowfall and snowmelt and the simulated discharge was computed from the soil moisture accounting (SMA) model of the US NWS and compared to the measured discharge. The elevationally distributed snow cover extent presented different patterns with different time of maximization, extinction and return during the year, producing different timing of discharge that is a crucial factor for the control and management of water resources systems.

Investigation of geophysical fields in pyrite deposits under mountainous conditions

NASA Astrophysics Data System (ADS)

Khesin, B. E.; Alexeyev, V. V.; Eppelbaum, L. V.

1993-05-01

Geophysical surveys under mountainous conditions are generally complicated by various noises, primarily by rugged topography effects. A rational integration of mobile geophysical methods (gravity prospecting, magnetic prospecting and VLF technique has been substantiated and effective methods of interpretation have been developed for copper pyrite deposits of a Kuroko type (an important source of non-ferrous and noble metals) not infrequently occurring in mountainous regions. A special scheme for obtaining the Bouguer anomalies has been employed to suppress the terrain relief effects dampening the anomaly effects from the objects of prospecting. The scheme is based on calculating the difference between the free-air anomaly ( Δg F.a) and the field determined from a 3-D model of a uniform medium with a real topography. This scheme almost doubled the accuracy of the Δg B chart. The further interpretation includes the following basic steps: (1) singling out the object of search using summation of the amounts of information obtained in various fields; (2) revision of the geological section using the methods specially devised for quantitative interpretation of anomalies under conditions of a rugged topography, inclined polarization and an unknown level of the normal field; and (3) physical-geological simulation realized as man-computer selection with the use of an effective algorithm for solving a direct 3-D problem of gravity and magnetic prospecting under the conditions of complex mediums and rugged observation surfaces. The method has been successfully tested at various stages of geophysical investigation under a variety of geological conditions, including saturated prospecting on the Kuroko-type Kyzylbulakh deposit (Lesser Caucasus) which has been thoroughly investigated by mining and drilling operations.

Evaluating and Improving Wind Forecasts over South China: The Role of Orographic Parameterization in the GRAPES Model

NASA Astrophysics Data System (ADS)

Zhong, Shuixin; Chen, Zitong; Xu, Daosheng; Zhang, Yanxia

2018-06-01

Unresolved small-scale orographic (SSO) drags are parameterized in a regional model based on the Global/Regional Assimilation and Prediction System for the Tropical Mesoscale Model (GRAPES TMM). The SSO drags are represented by adding a sink term in the momentum equations. The maximum height of the mountain within the grid box is adopted in the SSO parameterization (SSOP) scheme as compensation for the drag. The effects of the unresolved topography are parameterized as the feedbacks to the momentum tendencies on the first model level in planetary boundary layer (PBL) parameterization. The SSOP scheme has been implemented and coupled with the PBL parameterization scheme within the model physics package. A monthly simulation is designed to examine the performance of the SSOP scheme over the complex terrain areas located in the southwest of Guangdong. The verification results show that the surface wind speed bias has been much alleviated by adopting the SSOP scheme, in addition to reduction of the wind bias in the lower troposphere. The target verification over Xinyi shows that the simulations with the SSOP scheme provide improved wind estimation over the complex regions in the southwest of Guangdong.

Three-dimensional information extraction from GaoFen-1 satellite images for landslide monitoring

NASA Astrophysics Data System (ADS)

Wang, Shixin; Yang, Baolin; Zhou, Yi; Wang, Futao; Zhang, Rui; Zhao, Qing

2018-05-01

To more efficiently use GaoFen-1 (GF-1) satellite images for landslide emergency monitoring, a Digital Surface Model (DSM) can be generated from GF-1 across-track stereo image pairs to build a terrain dataset. This study proposes a landslide 3D information extraction method based on the terrain changes of slope objects. The slope objects are mergences of segmented image objects which have similar aspects; and the terrain changes are calculated from the post-disaster Digital Elevation Model (DEM) from GF-1 and the pre-disaster DEM from GDEM V2. A high mountain landslide that occurred in Wenchuan County, Sichuan Province is used to conduct a 3D information extraction test. The extracted total area of the landslide is 22.58 ha; the displaced earth volume is 652,100 m3; and the average sliding direction is 263.83°. The accuracies of them are 0.89, 0.87 and 0.95, respectively. Thus, the proposed method expands the application of GF-1 satellite images to the field of landslide emergency monitoring.

Occlusion-free animation of driving routes for car navigation systems.

PubMed

Takahashi, Shigeo; Yoshida, Kenichi; Shimada, Kenji; Nishita, Tomoyuki

2006-01-01

This paper presents a method for occlusion-free animation of geographical landmarks, and its application to a new type of car navigation system in which driving routes of interest are always visible. This is achieved by animating a nonperspective image where geographical landmarks such as mountain tops and roads are rendered as if they are seen from different viewpoints. The technical contribution of this paper lies in formulating the nonperspective terrain navigation as an inverse problem of continuously deforming a 3D terrain surface from the 2D screen arrangement of its associated geographical landmarks. The present approach provides a perceptually reasonable compromise between the navigation clarity and visual realism where the corresponding nonperspective view is fully augmented by assigning appropriate textures and shading effects to the terrain surface according to its geometry. An eye tracking experiment is conducted to prove that the present approach actually exhibits visually-pleasing navigation frames while users can clearly recognize the shape of the driving route without occlusion, together with the spatial configuration of geographical landmarks in its neighborhood.

Subtropical Dust Storms and Downslope Wind Events

NASA Astrophysics Data System (ADS)

Pokharel, Ashok Kumar; Kaplan, Michael L.; Fiedler, Stephanie

2017-10-01

We performed detailed mesoscale observational analyses and Weather Research and Forecasting (WRF) model simulations to study the terrain-induced downslope winds that generated dust-emitting winds at the beginning of three strong subtropical dust storms in three distinctly different regions of North Africa and the Arabian Peninsula. We revisit the Harmattan dust storm of 2 March 2004, the Saudi dust storm of 9 March 2009, and the Bodélé Depression dust storm of 8 December 2011 and use high-resolution WRF modeling to assess the dynamical processes during the onset of the storms in more depth. Our results highlight the generation of terrain-induced downslope winds in response to the transition of the atmospheric flow from a subcritical to supercritical state in all three cases. These events precede the unbalanced adjustment processes in the lee of the mountain ranges that produced larger-scale dust aerosol mobilization and transport. We see that only the higher-resolution data sets can resolve the mesoscale processes, which are mainly responsible for creating strong low-level terrain-induced downslope winds leading to the initial dust storms.

Collaborative Project. 3D Radiative Transfer Parameterization Over Mountains/Snow for High-Resolution Climate Models. Fast physics and Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liou, Kuo-Nan

2016-02-09

Under the support of the aforementioned DOE Grant, we have made two fundamental contributions to atmospheric and climate sciences: (1) Develop an efficient 3-D radiative transfer parameterization for application to intense and intricate inhomogeneous mountain/snow regions. (2) Innovate a stochastic parameterization for light absorption by internally mixed black carbon and dust particles in snow grains for understanding and physical insight into snow albedo reduction in climate models. With reference to item (1), we divided solar fluxes reaching mountain surfaces into five components: direct and diffuse fluxes, direct- and diffuse-reflected fluxes, and coupled mountain-mountain flux. “Exact” 3D Monte Carlo photon tracingmore » computations can then be performed for these solar flux components to compare with those calculated from the conventional plane-parallel (PP) radiative transfer program readily available in climate models. Subsequently, Parameterizations of the deviations of 3D from PP results for five flux components are carried out by means of the multiple linear regression analysis associated with topographic information, including elevation, solar incident angle, sky view factor, and terrain configuration factor. We derived five regression equations with high statistical correlations for flux deviations and successfully incorporated this efficient parameterization into WRF model, which was used as the testbed in connection with the Fu-Liou-Gu PP radiation scheme that has been included in the WRF physics package. Incorporating this 3D parameterization program, we conducted simulations of WRF and CCSM4 to understand and evaluate the mountain/snow effect on snow albedo reduction during seasonal transition and the interannual variability for snowmelt, cloud cover, and precipitation over the Western United States presented in the final report. With reference to item (2), we developed in our previous research a geometric-optics surface-wave approach (GOS) for the computation of light absorption and scattering by complex and inhomogeneous particles for application to aggregates and snow grains with external and internal mixing structures. We demonstrated that a small black (BC) particle on the order of 1 μm internally mixed with snow grains could effectively reduce visible snow albedo by as much as 5–10%. Following this work and within the context of DOE support, we have made two key accomplishments presented in the attached final report.« less

Stably stratified canopy flow in complex terrain

NASA Astrophysics Data System (ADS)

Xu, X.; Yi, C.; Kutter, E.

2015-07-01

Stably stratified canopy flow in complex terrain has been considered a difficult condition for measuring net ecosystem-atmosphere exchanges of carbon, water vapor, and energy. A long-standing advection error in eddy-flux measurements is caused by stably stratified canopy flow. Such a condition with strong thermal gradient and less turbulent air is also difficult for modeling. To understand the challenging atmospheric condition for eddy-flux measurements, we use the renormalized group (RNG) k-ϵ turbulence model to investigate the main characteristics of stably stratified canopy flows in complex terrain. In this two-dimensional simulation, we imposed persistent constant heat flux at ground surface and linearly increasing cooling rate in the upper-canopy layer, vertically varying dissipative force from canopy drag elements, buoyancy forcing induced from thermal stratification and the hill terrain. These strong boundary effects keep nonlinearity in the two-dimensional Navier-Stokes equations high enough to generate turbulent behavior. The fundamental characteristics of nighttime canopy flow over complex terrain measured by the small number of available multi-tower advection experiments can be reproduced by this numerical simulation, such as (1) unstable layer in the canopy and super-stable layers associated with flow decoupling in deep canopy and near the top of canopy; (2) sub-canopy drainage flow and drainage flow near the top of canopy in calm night; (3) upward momentum transfer in canopy, downward heat transfer in upper canopy and upward heat transfer in deep canopy; and (4) large buoyancy suppression and weak shear production in strong stability.

Irregular-Mesh Terrain Analysis and Incident Solar Radiation for Continuous Hydrologic Modeling in Mountain Watersheds

NASA Astrophysics Data System (ADS)

Moreno, H. A.; Ogden, F. L.; Alvarez, L. V.

2016-12-01

This research work presents a methodology for estimating terrain slope degree, aspect (slope orientation) and total incoming solar radiation from Triangular Irregular Network (TIN) terrain models. The algorithm accounts for self shading and cast shadows, sky view fractions for diffuse radiation, remote albedo and atmospheric backscattering, by using a vectorial approach within a topocentric coordinate system and establishing geometric relations between groups of TIN elements and the sun position. A normal vector to the surface of each TIN element describes slope and aspect while spherical trigonometry allows computingunit vector defining the position of the sun at each hour and day of the year. Thus, a dot product determines the radiation flux at each TIN element. Cast shadows are computed by scanning the projection of groups of TIN elements in the direction of the closest perpendicular plane to the sun vector only in the visible horizon range. Sky view fractions are computed by a simplified scanning algorithm from the highest to the lowest triangles along prescribed directions and visible distances, useful to determine diffuse radiation. Finally, remotealbedo is computed from the sky view fraction complementary functions for prescribed albedo values of the surrounding terrain only for significant angles above the horizon. The sensitivity of the different radiative components is tested a in a moutainuous watershed in Wyoming, to seasonal changes in weather and surrounding albedo (snow). This methodology represents an improvement on the current algorithms to compute terrain and radiation values on triangular-based models in an accurate and efficient manner. All terrain-related features (e.g. slope, aspect, sky view fraction) can be pre-computed and stored for easy access for a subsequent, progressive-in-time, numerical simulation.

Precipitation Estimate Using NEXRAD Ground-Based Radar Images: Validation, Calibration and Spatial Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xuesong

2012-12-17

Precipitation is an important input variable for hydrologic and ecological modeling and analysis. Next Generation Radar (NEXRAD) can provide precipitation products that cover most of the continental United States with a high resolution display of approximately 4 × 4 km2. Two major issues concerning the applications of NEXRAD data are (1) lack of a NEXRAD geo-processing and geo-referencing program and (2) bias correction of NEXRAD estimates. In this chapter, a geographic information system (GIS) based software that can automatically support processing of NEXRAD data for hydrologic and ecological models is presented. Some geostatistical approaches to calibrating NEXRAD data using rainmore » gauge data are introduced, and two case studies on evaluating accuracy of NEXRAD Multisensor Precipitation Estimator (MPE) and calibrating MPE with rain-gauge data are presented. The first case study examines the performance of MPE in mountainous region versus south plains and cold season versus warm season, as well as the effect of sub-grid variability and temporal scale on NEXRAD performance. From the results of the first case study, performance of MPE was found to be influenced by complex terrain, frozen precipitation, sub-grid variability, and temporal scale. Overall, the assessment of MPE indicates the importance of removing bias of the MPE precipitation product before its application, especially in the complex mountainous region. The second case study examines the performance of three MPE calibration methods using rain gauge observations in the Little River Experimental Watershed in Georgia. The comparison results show that no one method can perform better than the others in terms of all evaluation coefficients and for all time steps. For practical estimation of precipitation distribution, implementation of multiple methods to predict spatial precipitation is suggested.« less

Multi-Scale Observation and Modelling of Energy and Matter Exchange in the Atmospheric Boundary-Layer (ScaleX Campaigns)

NASA Astrophysics Data System (ADS)

Zeeman, M. J.; Wolz, K.; Adler, B.; Brenner, C.; De Roo, F.; Emeis, S.; Kalthoff, N.; Mauder, M.; Schäfer, K.; Wohlfahrt, G.; Zhao, P.

2016-12-01

We investigated biosphere-atmosphere exchange processes in relation to the atmospheric boundary-layer (ABL) flow in a shallow valley. Land-use heterogeneity and topography can force local atmospheric flow patterns, including local circulations. Such flow patterns can impair current techniques for the quantification and source attribution of surface-exchange fluxes due to flux-divergence, advection and decoupling. Wind field, temperature and humidity structures in the ABL were observed in high resolution with spatially distributed observations in a 1 km3 experimental domain. Remote-sensing observations of wind, temperature and particles in the ABL (Raman-lidar; RASS; ceilometer; microwave radiometer; 3D Doppler-lidar) were combined with a high-resolution network of in-situ observations that included vertical and horizontal profiles of wind, temperature, carbon dioxide, methane and water vapor concentrations. The experiments were co-located with the long-term eddy covariance (EC) observatory Fendt (DE-Fen; ICOS, TERENO) and were part of international cooperative efforts in 2015 and 2016 (the ScaleX campaigns). The gathered experimental data offers a scale-transcending insight in local flow patterns in mountainous terrain and their influence on surface-exchange fluxes of energy and matter as observed by EC and flux-gradient methodology. In addition, the data is used for validation of Large-Eddy Simulations in complex terrain using PALM-LES. Within this modelling framework, virtual measurements are conducted to further assess the importance of three-dimensional advective and horizontal turbulent transport terms.

A Laboratory Study of Slope Flows Dynamics

NASA Astrophysics Data System (ADS)

Capriati, Andrea; Cenedese, Antonio; Monti, Paolo

2003-11-01

Slope flows currents can contribute significantly in the diurnal circulation and air quality of complex terrain regions (mountains, valleys, etc.). During the daytime, solar heating warms the valley sides, causing up-slope (or anabatic) winds. In contrast, radiative cooling of the valley sides results in cold down-slope (drainage or katabatic) flows, characterized by small vertical extensions (usually 10-200 m) and with the typical features of dense gravity currents. In this paper, some preliminary results on slope flows obtained by means of a series of experiments conducted in the laboratory using a temperature controlled water tank are shown. Rakes of thermocouples are used to determine the temperature structure and particle tracking velocimetry is used for the velocity measurements. A simple slope consisting of a plate in which the temperature is forced via a set of Peltier Cells is used. The analysis is performed considering different slope angles, background thermal stratifications and surface heat fluxes as well. Comparisons with theoretical and empirical laws found in literature are reported.

Carbon dioxide transport over complex terrain

USGS Publications Warehouse

Sun, Jielun; Burns, Sean P.; Delany, A.C.; Oncley, S.P.; Turnipseed, A.; Stephens, B.; Guenther, A.; Anderson, D.E.; Monson, R.

2004-01-01

The nocturnal transport of carbon dioxide over complex terrain was investigated. The high carbon dioxide under very stable conditions flows to local low-ground. The regional drainage flow dominates the carbon dioxide transport at the 6 m above the ground and carbon dioxide was transported to the regional low ground. The results show that the local drainage flow was sensitive to turbulent mixing associated with local wind shear.

Inferring the contribution of advection to total ecosystem scalar fluxes over a tall forest in complex terrain

Treesearch

K. Novick; S. Brantley; C. Ford Miniat; J. Walker; J.M. Vose

2014-01-01

Multiple data streams from a new flux tower located in complex and heterogeneous terrain at theCoweeta Hydrologic Laboratory (North Carolina, USA) were integrated to identify periods of advectiveflow regimes. Drainage flows were expected a priori, due to the location of the measurement site at thebase of a long, gently-sloping valley. Drainage flow was confirmed by...

The assessment of EUMETSAT HSAF Snow Products for mountainuos areas in the eastern part of Turkey

NASA Astrophysics Data System (ADS)

Akyurek, Z.; Surer, S.; Beser, O.; Bolat, K.; Erturk, A. G.

2012-04-01

Monitoring the snow parameters (e.g. snow cover area, snow water equivalent) is a challenging work. Because of its natural physical properties, snow highly affects the evolution of weather from daily basis to climate on a longer time scale. The derivation of snow products over mountainous regions has been considered very challenging. This can be done by periodic and precise mapping of the snow cover. However inaccessibility and scarcity of the ground observations limit the snow cover mapping in the mountainous areas. Today, it is carried out operationally by means of optical satellite imagery and microwave radiometry. In retrieving the snow cover area from satellite images bring the problem of topographical variations within the footprint of satellite sensors and spatial and temporal variation of snow characteristics in the mountainous areas. Most of the global and regional operational snow products use generic algorithms for flat and mountainous areas. However the non-uniformity of the snow characteristics can only be modeled with different algorithms for mountain and flat areas. In this study the early findings of Satellite Application Facilities on Hydrology (H-SAF) project, which is financially supported by EUMETSAT, will be presented. Turkey is a part of the H-SAF project, both in product generation (eg. snow recognition, fractional snow cover and snow water equivalent) for mountainous regions for whole Europe, cal/val of satellite-derived snow products with ground observations and cal/val studies with hydrological modeling in the mountainous terrain of Europe. All the snow products are operational on a daily basis. For the snow recognition product (H10) for mountainous areas, spectral thresholding methods were applied on sub pixel scale of MSG-SEVIRI images. The different spectral characteristics of cloud, snow and land determined the structure of the algorithm and these characteristics were obtained from subjective classification of known snow cover features in the MSG/SEVIRI images. The fractional snow cover area (H12) algorithm is based on a sub-pixel reflectance model applied on METOP-AVHRR data. Knowing the effects of topography on satellite-measured radiances for rough terrain, the sun zenith and azimuth angles, as well as direction of observation relative to these are taken into account in estimating the target reflectances from the satellite images. The values of SWE products (H13) were obtained using an assimilation process based on the Helsinki University of Technology model using Advanced Microwave Scanning Radiometer for EOS (AMSR-E) daily brightness-temperature values. The validation studies for three products have been performed for the water years 2010 and 2011. Average values of 70% of probability of detection for snow recognition product, 60% of overall accuracy for the fractional snow cover product and 45 mm RMSE for the snow water equivalent product have been obtained from the validation studies. Final versions of these three products will be presented and discussed. Key words: snow, satellite images, mountain, HSAF, snow cover, snow water equivalent