3D Visualization for the Analysis of Forest Cover Change     

Matt D. Dunbar  L. Monika Moskal  Mark E. Jakubauskas 《国际地球制图》2013,28(2):103-112

Abstract

Visualization techniques have been developed to recreate natural landscapes, but little has been done to investigate their potential for illustrating land cover change using spatio‐temporal data. In this work, remote sensing, geographic information systems (GIS) and visualization techniques were applied to generate realistic computer visualizations depicting the dynamic nature of forested environments. High resolution digital imagery and aerial photography were classified using object‐oriented methods. The resulting classifications, along with preexisting land cover datasets, were used to drive the correct placement of vegetation in the visualized landscape, providing an accurate representation of reality at various points in time. 3D Nature's Visual Nature Studio was used to construct a variety of realistic images and animations depicting forest cover change in two distinct ecological settings. Visualizations from Yellowstone National Park focused on the dramatic impact of the 1988 fire upon the lodgepole pine forest. For a study area in Kansas, visualization techniques were used to explore the continuous human‐land interactions impacting the eastern deciduous forest and tallgrass prairie ecotone between 1941 and 2002. The resulting products demonstrate the flexibility and effectiveness of visualizations for representing spatio‐temporal patterns such as changing forest cover. These geographic visualizations allow users to communicate findings and explore new hypotheses in a clear, concise and effective manner.  相似文献   

High-precision measurement of oceanic 226Ra     

Peter Schlosser  Monika Rhein  Wolfgang Roether  Bernd Kromer 《Marine Chemistry》1984,15(3):203-216

A system capable of oceanic ²²⁶Ra measurements with a precision of ±1% is described, which represents an improvement of approximately a factor of three over existing techniques. ²²²Rn grown-in from ²²⁶Ra decay in 14-l seawater samples is quantitatively transferred to, and measured in, proportional gas counters. Errors other than counting statistics are estimated not to exceed ±0.5%, which is consistent with repeated ²²⁶Ra measurements on the same samples. A NE Atlantic ²²⁶Ra depth profile (2000–5000 m) is reported as an example. It is found that with the precision reported here, certain hitherto unresolved features of the ²²⁶Ra distribution in deep water become apparent.  相似文献   

Improvement of lithology and saturation determined from well logging using statistical methods     

Monika Kaźmierczuk  Jadwiga Jarzyna 《Acta Geophysica》2006,54(4):378-398

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The sipunculan fauna of Svalbard   总被引：2，自引：0，他引：2  

Monika K&#;dra  & Galena V. Murina 《Polar research》2007,26(1):37-47

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Shallow groundwater in a middle mountain catchment of Nepal: quantity and quality issues   总被引：1，自引：0，他引：1  

Bhawani S. Dongol  Juerg Merz  Monika Schaffner  Gopal Nakarmi  Pravakar B. Shah  Smita K. Shrestha  Pradeep M. Dangol  Madhav P. Dhakal 《Environmental Geology》2005,49(2):219-229

The use of shallow groundwater in middle mountain catchments of Nepal is a recent development. It was only in early 1998 that a number of dug wells had been constructed in the Jhikhu Khola catchment. But their numbers are rapidly increasing. While it seems to be a good way of accessing additional water resources both for domestic (current) and agricultural purposes (future), it is very important that the groundwater resources are not overexploited. Current dug wells are used to abstract groundwater, which is seasonally being recharged by the abundant monsoon rainfall. The water levels responded rapidly to the rainfall and differed according to the location of the well. The water quality parameters indicated that the water of most of the wells was not suitable for drinking purposes without prior treatment. Microbiological contamination is of particular concern, in addition to the high nitrate and phosphate levels. Some wells show elevated turbidity levels, indicating that there is an interaction between the muddy surface water and the water in the well.  相似文献   

Discharge and transport processes along the German Baltic Sea Coast     

Herbert Siegel  Torsten Seifert  Gerald Schernewski  Monika Gerth  Thomas Ohde  Jan Reißmann  Victor Podsetchine 《Ocean Dynamics》2005,55(1):47-66

The western Baltic Sea infront of the German coast is a highly variable dynamical system, dominated by a complex and small-scale morphometry, the water exchange between the Baltic and North Seas, and driven by local wind. Neither data collection, nor satellite images or model simulations alone were able to explain the observed spatial patterns and transport processes. Therefore, all these methods were combined to explain the dynamical features and to systematise them according to the typical local wind pattern and time series. The aim was to develop an instrument for regional authorities which supports the interpretation of coastal water monitoring data and forms a basis for an improved monitoring strategy. Satellite data of sea surface temperature and ocean colour from the sensors NOAA-AVHRR and SeaWiFS were applied for synoptic investigations in the entire region and Landsat-7-ETM+ for regional studies. Model simulations were performed for the western Baltic using a 3D model MOM-3 and for the Szczecin Lagoon using 2D model FEMFLOW. For the first time, regional particularities in the coastal dynamical features and processes are derived for the main wind directions and for transitions between dominant wind situations west and east as derived from wind statistics. The simulated transport of particles released from different coastal and open sea sources indicate the affected areas during changing forcing conditions. The results support the interpretation of acquired coastal monitoring data as well as the assessment and optimisation of the monitoring programme.  相似文献   

Measurements of Volatile Organic Compounds (VOC) During POPCORN 1994: Applying a New On-Line GC–MS-Technique     

Arno Wedel  Klaus-Peter Müller  Monika Ratte  Jochen Rudolph 《Journal of Atmospheric Chemistry》1998,31(1-2):73-103

Atmospheric concentrations of ca. 250 C6–C15 hydrocarb on and C4–C12 oxygenated volatile organic compounds (VOC) including alkanes, benzene and alkyl benzenes, monoterpenes and aldehydes were measured in August 1994 during the POPCORN campaign (POPCORN = Photo-Oxidant formation by Plant emitted Compounds and OH Radicals in North-Eastern Germany). About 80 substances together contributed 90% of the atmospheric carbon in this range of molecular weight. During this field campaign VOC-emissions from several crop and tree species and the ambient concentrations of CO, C2–C7 non-methane hydrocarbons (NMHC), C1 and C2 aldehydes, nitrogen oxides, ozone and hydroxyl-radicals (OH) were also measured. These data were used to interpret the VOC measurements presented here. The on-line GC–MS used for the VOC measurements combines adsorptive sampling with thermal desorption and GC–MS analysis in an automated system. Internal standards were used to quantify the measurements. Ozone was destroyed prior to the sample preconcentration through the gas phase reaction with NO. Aromatic compounds like benzene, toluene and xylenes were the most abundant compound class among the measured substances, -pinene and 3-carene, most probably originating from pineforests ca. 1 km away from the measuring site, were the most abundant monoterpenes. The highest mixing ratios of most compounds were measured in nights with strong inversion situations. The toluene mixing ratios then reached 630 pptv; -pinene mixing ratios went up to 430 pptv. The median of all toluene and -pinene measurements during the campaign was 125 pptv or 22 pptv, respectively. These values are on the lower end of ambient measurements reported for continental sites. In most samples also n-pentanal, n-hexananl, n-nonanal and n-undecanal were present. Median mixing ratios were 9, 16, 14 and 8 pptv, respectively. Emission studies indicate that these highly reactive compounds are most probably emitted from maize. It is shown by a simple first order approach that the potential for ozone formation during the POPCORN campaign was roughly equal for anthropogenic and biogenic VOC. From measured concentrations of ozone, OH-radicals, methane, CO, C2–C15 nonmethane hydrocarbons (NMHC) and C5–C11 aldehydes a photochemical production of ozone in the order of 3.5 ppb/h can be estimated. Apart from formaldehyde and acetaldehyde, which are at least partly products of VOC oxidation, the substance group with the largest contribution to the VOC turnover are the monoterpenes. They contribute ca. 30%. However, the mechanism of terpene oxidation is very complex and presently only partly understood. Thus the actual contribution of monoterpenes to ozone formation is very uncertain. Other measured compound classes such as light alkenes, alkanes, aromatics, and C5–C11 aldehydes contribute each between 10% and 15% to ozone formation. The measuring site was not influenced directly from strong biogenic or anthropogenic sources, and the results obtained during the POPCORN campaign can be regarded as a typical picture of a remote rural central European environment.  相似文献   

Transport of South Atlantic water through the passages south of Guadeloupe and across 16°N, 2000–2004   总被引：1，自引：1，他引：1  

Monika Rhein  Kerstin Kirchner  Christian Mertens  Reiner Steinfeldt  Maren Walter  Ulrich Fleischmann-Wischnath 《Deep Sea Research Part I: Oceanographic Research Papers》2005,52(12):2234-2249

CTD, vessel-mounted ADCP and LADCP measurements in the Caribbean passages south of Guadeloupe (three repeats) and along 16°N (five repeats) were carried out between December 2000 and July 2004. The CTD data were used to calculate the contribution of South Atlantic water (SAW) in the upper 1200 m between the isopycnals σ_θ=24.5 and 27.6. Northern and southern source water masses are defined and an isopycnal mixing approach is applied. The SAW fractions are then combined with the ADCP flow field to calculate the transport of SAW into the Caribbean and across 16°N. The SAW inflow into the Caribbean through the passages south of Guadeloupe ranges from 7.6 to 11.6 Sv, which is 50–75% of the total inflow. The mean (9.1±2.2 Sv) is in the range of previous estimates. Ambiguities in the northern and southern source water masses of the salinity maximum water permitted us only to calculate the contribution of SAW from the eastern source in this water mass. We estimated the additional SAW transport by the western source to be of the order of 1.9±0.7 Sv. The calculation of the SAW transport across 16°N was hampered by the presence of several anticyclonic rings from the North Brazil Current (NBC) retroflection region, some of the rings were subsurface intensified. Provided that the rings observed at 16°N are typical rings and that all rings which are annually produced in the NBC retroflection area (6.5–8.5 per year) reach 16°N, the SAW ring transport across 16°N is calculated to 5.3±0.7 Sv. From the 5 repeats at 16°N, only two showed a net northward flow, suggesting that the mean northward SAW transport is dominated by ring advection. The joint SAW transports of the Caribbean inflow (9.1 Sv) and the flow across 16°N (5.3 Sv) sum up to 14.4 Sv. The transport increases to 16.3 Sv if the additional SAW transport from the western source of SMW (1.9±0.7 Sv) is included. These transport estimates and the following implications depend strongly on the assumption that the surface water in the Caribbean inflow is of South Atlantic origin. The transport estimates are, however, in the range of the inverse model calculations for the net cross-hemispheric flow. About 30–40% of this transport is intermediate water from the South Atlantic, presumably supporting studies which found the contributions of intermediate and upper warm water to be of a comparable magnitude. For the upper warm water (σ_θ<27.1), the Caribbean inflow seems to be the major path (7.9±1.6 Sv), the ring induced transport across 16°N is about 30% of that value. The intermediate water transport across 16°N was calculated to be 2.3–3.6 Sv, the inflow into the Caribbean is slightly smaller (1.5–2.4 Sv).  相似文献   

Quality assessment of OpenStreetMap data using trajectory mining   总被引：1，自引：0，他引：1  

Anahid Basiri  Mike Jackson  Pouria Amirian  Amir Pourabdollah  Monika Sester  Adam Winstanley 《地球空间信息科学学报》2016,19(1):56-68

OpenStreetMap (OSM) data are widely used but their reliability is still variable. Many contributors to OSM have not been trained in geography or surveying and consequently their contributions, including geometry and attribute data inserts, deletions, and updates, can be inaccurate, incomplete, inconsistent, or vague. There are some mechanisms and applications dedicated to discovering bugs and errors in OSM data. Such systems can remove errors through user-checks and applying predefined rules but they need an extra control process to check the real-world validity of suspected errors and bugs. This paper focuses on finding bugs and errors based on patterns and rules extracted from the tracking data of users. The underlying idea is that certain characteristics of user trajectories are directly linked to the type of feature. Using such rules, some sets of potential bugs and errors can be identified and stored for further investigations.  相似文献   

New interpretations of the facies of the rhenish brown coal of West Germany     

Hans W. Hagemann  Monika Wolf 《International Journal of Coal Geology》1987,7(4)

New ideas concerning the understanding of the facies of the Rhenish brown coal of West Germany are discussed. These new interpretations are based on a significantly larger number of samples and refined procedures for analysis within the field of paleobotany, palynology, coal petrology and organic geochemistry than were available to P. W. Thomson and M. Teichmüller. The light and dark bands in the coal are mainly the result of different degrees of plant decomposition. The influence of the peat-forming plant communities plays a subordinate role in the petrographical composition of these particular strata of the Rhenish brown coal.  相似文献