Spatial Variability Research Papers - Academia.edu (original) (raw)

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- Earth Sciences, Biological Sciences, Sediment transport, Spatial Scale

The temporal evolution of nine daily precipitation indices over the northeastern Iberian Peninsula was analysed for the period 1955–2006, using data from 217 observatories. Cross-tabulation analysis enabled detection of statistically significant overlap among spatial distributions of trends in the study area. There was a general decrease in annual precipitation at most observatories, a decrease in the number of rainy days and precipitation intensity and an increase in the duration of dry spells. The frequency and contribution to annual precipitation of moderate and heavy rainfall events did not change at most observatories, or showed a decreasing trend in these events. There was very large spatial and seasonal variability, with implications for water management and risk assessment in the region. The decrease in precipitation was very marked in headwaters during winter and spring, potentially affecting reservoir management in the region. Heavy rainfall events generally decreased in the west of the region in winter, and in the east of the region in autumn, when these areas are more exposed to hazards related to extreme rainfall. Large differences in the sign and magnitude of trends occurred over very short distances, suggesting the need for dense networks of observatories to ensure reliable and robust detection of regional trends. Copyright © 2009 Royal Meteorological Society

- by Aira Windfeather
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- Environmental Engineering, Civil Engineering, Climatology, Atmospheric sciences
- by Kálmán Rajkai
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- Environmental Science, Scaling, Spatial Variability, Soil Hydraulic Properties
- by Agostino Ferrara
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- Time Series, Climate variability, Forest, Missing Data

Quantifying the relationship between mesozooplankton and water quality parameters identifies the factors that structure the mesozooplankton community and can be used to generate hypotheses regarding the mechanisms that control the mesozooplankton population and potentially the trophic network. To investigate this relationship, mesozooplankton and water quality data were collected in Florida Bay from 1994 to 2004. Three key characteristics were found in the mesozooplankton community structure: (1) there are significant differences between the four sub-regions of Florida Bay; (2) there is a break in May of 1997 with significant differences before and after this date; and (3) there is a positive correlation between mesozooplankton abundance and salinity. The latter two characteristics are closely correlated with predator abundance, indicating the importance of top-down control. Hypersaline periods appear to provide a refuge from predators, allowing mesozooplankton to increase in abundance despite the increased physiological stress.

- by Gary Hitchcock
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- Earth Sciences, Water quality, Biological Sciences, Environmental Sciences
- by John Silander
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- Climate Change, South Korea, East Asia, Global Warming
- by raffaele grasso
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- Oceanography, Sea surface temperature, Spatial Variability, Satellite Data
- by Mark White
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- Engineering, Mechanical Engineering, Aerospace Engineering, Visual perception
- by Jorg Imberger
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- Environmental Engineering, Water quality, Great Lakes, Seasonality
- by indra jaya
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- Geochemistry, Oceanography, Hydrography, Indian Ocean
- by Alexei Kouraev
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- Earth Sciences, Limnology, Lake Baikal, Biological Sciences
- by Asa Ferrier
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- Evolutionary Biology, Archaeology, Prehistoric Archaeology, Geology
- by Ana Barros
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- Geology, Natural Hazards, Seasonality, Altitudinal gradient
- by Joost Brouwer
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- Precision Agriculture, West Africa, Sensitivity Analysis, Environmental Sciences
- by Mary Christman and +2
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- Biological Sciences, Environmental Sciences, Water Temperature, Spatial Variability

The tidal migration, temporal and spatial patterns in feeding of the surface-swimming four-eyed fish Anableps anableps (Anablepidae) were studied in a macrotidal mangrove area in north Brazil to exemplify the ecology of a tropical intertidal fish. Visual censuses in the main channel showed that abundances were high at low water (LW) and low at high water (HW). Anableps anableps entered the intertidal creeks with the first flood rise. They fed in the inundated mangrove at HW and returned gradually after the ebb current maximum to concentrate again in the subtidal parts of the main channel at LW. This pattern occurred at neap, mid and spring tides throughout the year. The tidal migration was triggered by water level, not by time. In the study area the diet of A. anableps caught with block nets was dominated by intertidal red algae (Catanella sp.). Other important food items were Insecta and Grapsidae. The combination of high inundation and daylight (spring tide-day) provided the best foraging conditions, probably emphasizing the importance of the above-water eye. Darkness and low inundation was linked to poorest foraging conditions (neap tide-night). The quantity of food consumed by A. anableps was clearly influenced by the factors tide, time of day and creek location, but not by size and sex. The qualitative composition of the diet was not influenced by any of the factors, except for mud, which was only ingested at neap tides. The temporal and spatial variability in food consumption suggests that food web modelling in macrotidal areas may lead to misinterpretations of the overall systems dynamics if the spring and neap tide alternation and the diurnal cycle are not considered.

- by Uwe Krumme
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- Zoology, Ecology, System Dynamics, Fish Biology
- by Timo Vihma
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- Geology, Oceanography, Thermodynamics, Time Series
- by Angela Kent
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- Computational Biology, Multidisciplinary, Phylogeny, Gene Cloning
- by Alison McCarthy
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- Management, Engineering, Adaptive Control, Simulation
- by Anthony Purcell
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- Earth Sciences, Sea Level, Physical sciences, Spatial Variability

Studies on denudation rates can provide insight into the influence of climate change, tectonics, and human activities on landscape evolution. Research performed in Central Italy has shown considerable spatial variability of denudation rates in the major river basins. These studies have focused mainly on the Tyrrhenian side of the Italian peninsula, where Plio-Pleistocene marine deposits filling NW–SE elongated sedimentary basins have been uplifted during the Quaternary up to several hundreds of meters above present sea level. Small sub-catchments developed on clays are affected by sharp- and/or rounded-edged badlands (i.e. calanchi and biancane), representing denudation “hot spots” in the present-day morphoclimatic framework.In this paper, we analyze the relationships between indirectly estimated denudation rates at the catchment scale and field monitoring data at the hillslope scale. We attempt to better understand and quantify all hillslope processes that contribute to seasonal variability of denudation, to help with predicting the net input from “hot spots” to the overall estimated sediment yield at the basin outlets. At the hillslope scale, we discuss, in particular, the variability of denudation rates at calanchi and biancane badlands as a function of their different morphoevolution.

- by Marta Della Seta
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- Geology, Geomorphology, Climate Change, Sea Level

Chandra, S., Chhetri, P. and J. Corcoran (2009).Spatial patterns of urban compactness in Melbourne: an urban myth or a reality. In: Ostendorf B., Baldock, P., Bruce, D., Burdett, M. and P. Corcoran (eds.), Proceedings of the Surveying &... more

- by Prem Chhetri
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- Urban Planning, Urban form, Local governance, Count data

To detect soil changes related to vegetation and fertility restoration in a long fallow agricultural system of the Venezuelan Andes, 32 soil (A horizon, 0–15cm depth) and litter characteristics were studied in plots at different stages of the fallow-cultivation cycle. Four sectors of the valley were sampled, each one including seven plots: recently ploughed after a long fallow period; 1

- by Lina Sarmiento
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- Environmental Science, Carbon Cycle, Nitrogen Cycle, Potato
- by El-Sayed Omran
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- Groundwater, Heavy metals, Water Quality Index, Kriging

When this is written, the world holds its breath, waiting for the US to decide on a plan to save the countrys (and the worlds in prolongation) financial market. What and who will dictate growth and prosperity internationally in the future are at stake. This is also a moment for developing deeper understanding of underlying spatial prerequisites for the interdependency of local, regional and global knowledge driven economies. This paper introduces a proposed research project with an aim to analyse the relation between the spatial constitution of urban regions and their relative success in the international competition for talent, capital and investments. Spatial analysis will be conducted both on the macro level: the relation and accessibility between urban regional nodes and on the micro level: the spatial structure of the urban nodes themselves. The project is a trans-disciplinary collaboration between economic geography and urban morphology and has the following objectives: one, t...

- by Lars Marcus
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- Geography, Economic Geography, Spatial Analysis, Economic Growth
- by Eric Colhoun
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- Archaeology, Earth Sciences, Geology, Sedimentology
- by S.h.l.l. Gruijters
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- Geology, Geochemistry, Geophysics, Grain size distribution

Field experience has shown that soil conditions can have large effects on Ground Penetrating Radar (GPR) detection of landmines. We discuss available models for the prediction of the dielectric constant from soil physical properties including bulk density, soil texture, and water content. The soil dielectric constant determines the attenuation of the radar signal. The contrast between the dielectric constant of

- by Brian Borchers and +1
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- Ground Penetrating Radar, Field Experiment, Spatial Variability, Dielectric Constant
- by Axel Bronstert
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- Hydrology, Multidisciplinary, Soil moisture, Large River Ecology

Snow cover is a highly variable land surface condition that exerts a strong control on the heat and moisture budget of the overlying atmosphere. Modeling studies based on long integrations of global circulation models (GCM) are normally carried out at very low resolution (typically coarser than 100 km) due to their high computational demand. On local scales, snow cover plays an important socioeconomic role, ranging from water management applications to outdoor recreation. These latter applications vary in horizontal resolution from a few hundred meters to a few kilometers, where small scale topography, land cover and local circulation effects play a significant role. In this study our focus will be on horizontal scales ranging from typical GCM global climate modeling to high resolution global weather forecasts. In the land surface component of a GCM (land surface model - LSM), snow cover temporal and spatial variability is mainly determined by the overlying atmospheric conditions. However, once snowfall settles on the ground, the sub-grid scale variability associated with complex terrain and land cover variability (not resolved at the model resolution) is parameterized following simple physical and/or empirical relations. The present study intends to access the impact of horizontal resolution in the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface model (HTESSEL). HTESSEL is forced by the ECMWF operational weather forecasts since March 2006 to December 2009 (runs in offline/stand-alone mode). The control run is carried out at the horizontal resolution of the forecasts at TL799 (gaussian reduced grid N400 -about 25 km). Two lower horizontal resolutions are then tested: TL255 (gaussian reduced grid - about 80 km, same as the ERA-Interim reanalysis), and TL95 (gaussian reduced grid N48 - about 200 km). The length of the simulations is rather small (only 46 months), however global meteorological forcing at 25 km can only be accessed through the ECMWF recent weather forecasts. Such high resolution associated with the state of the art modeling and assimilation frameworks guarantees that the atmospheric conditions seen by the LSM are as close as possible to reality. To assure that the two lower horizontal resolution simulations have a good quality forcing, an energy/mass conserving remapping was applied when upscaling the forcing fields. Special care was taken for the upscaling of temperature, specific humidity, surface pressure and downward longwave radiation considering the changes in mean orography between resolutions. Snow cover simulations are validated against two daily observational products: 1) IMS Daily Northern Hemisphere Snow and Ice Analysis at 4 km resolution (National Snow and Ice Data Center) and 2) SNOWCLIM snow depth daily European domain at 0.1° resolution (German Weather Service). The present work is focused over Europe, namely in four domains: Alps, Central and Eastern Europe and Scandinavia, where conditional spatial sampling is performed in order to distinguish between complex versus flat terrain and forest versus exposed (low vegetation and bare ground) areas. The results are model dependent, but allow deriving important relations between resolution, orography and vegetation variability impacts on snow cover simulations.

- by Pedro Miranda
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- Eastern Europe, Outdoor Recreation, Atmospheric Modeling, Water Management
- by Juan Hidalgo
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- Environmental Engineering, Civil Engineering, Water resources, Groundwater

Deterioration of reinforced concrete and the reliability of deteriorating structures have been, and still are, widely researched fields. A critical aspect of this research effort is the integration of deterioration modelling with reliability assessment. This paper focuses on this issue and illustrates how the integration of these techniques can lead towards more realistic predictions of the time dependent performance of reinforced concrete bridge structures. The introduction of spatial random fields into the proposed approach facilitates the identification of the type and quantity of data required to update models and improve predictions. This is an essential step in the rational prioritisation of maintenance actions for such structures. However, there are still important gaps both in understanding and modelling the deterioration process, as well as in assessing its influence on bridge performance. In this respect, the methodology presented in the paper can be developed further, and...

- by Marios Chryssanthopoulos
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- Reliability, Spatial Variability, Bridges, Reinforced concrete
- by Stephen Herbert
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- Plant Biology, Spatial autocorrelation, Water Table, Coefficient of Variation
- by Jianye Xu
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- Earth Sciences, Biological Sciences, Eddy Covariance, Energy Balance

In agriculture, there is growing interest in determining field spatial variability for implementing differential management practices, which should generate economic and environmental benefits. To date, the majority of studies involving remote sensing and differential management have focused on optical sensor systems. Less attention has been paid to synthetic aperture radar (SAR), despite the advantages of "all-weather" acquisition enabling information to

- by Alistair Smith
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- Remote Sensing, Canadian, Seasonality, Optical Sensor
- by Lynn Gelhar
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- Environmental Engineering, Civil Engineering, Water resources, Stochastic analysis
- by Tamás Szentimrey
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- Environmental Engineering, Civil Engineering, Climatology, Time Series
- by Yahaya Nazoumou
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- Geophysics, Groundwater recharge, Applied Geophysics, Magnetic Resonance
- by Jennifer Richmond-bryant
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- Architecture, Indoor Air Quality, Computation Fluid Dynamics, Building
- by Timothy Milligan
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- Earth Sciences, Turbulence, Biological Sciences, Environmental Sciences
- by Aleksei Chechkin
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- Engineering, Computational Physics, Multidisciplinary, Numerical Method

... The distribution of riverine sediment stores and sinks, and the frequency with which sediment is added or removed from compartments, reflects the degree to which a river system is (dis)connected or (de)coupled (Caine and Swanson,... more

- by Kirstie Fryirs
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- Geology, Geomorphology, New South Wales, Spatial Distribution
- by Michel Mench
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- Phytoremediation, Bioremediation, Biodiversity, Plant Diversity