Skip to main content

page search

Issuesland coverLandLibrary Resource
There are 2, 240 content items of different types and languages related to land cover on the Land Portal.
Displaying 769 - 780 of 2218

Application of a Bayesian network for land-cover classification from a Landsat 7 ETM+ image

Journal Articles & Books
December, 2011
Eswatini

This article describes the use of a Bayesian network (BN) for the classification of land cover from satellite imagery in northern Swaziland. The main objective of this work was to apply and evaluate the efficacy of a BN for land-cover classification using gap-filled and terrain-corrected Landsat 7 Enhanced Thematic Mapper Plus (ETM+) imagery acquired on 15 May 2007. The posterior probabilities (parameters) were estimated using the expectation-maximization (EM) and conjugate gradient descent (CGD) algorithms.

Land-cover changes and potential impacts on soil erosion in the Nan watershed, Thailand

Journal Articles & Books
December, 2011
Thailand

The expansion of built environments and agriculture land in the Nan watershed, Thailand, to support the rapid increase of the national population has resulted in deforestation, thus affecting the ecological balance. This deforestation, especially in high mountainous areas, has led to serious environmental degradation. Recent reports reveal an increasing soil-erosion problem in the watershed. This study analyses land-use and land-cover (LULC) changes and their potential impact on soil erosion during a study period between 1995 and 2005.

Scale-dependent relations in land cover biophysical dynamics

Journal Articles & Books
December, 2011
Italy

The exploration of the relationships between plant biotic dynamics and scale can reveal important information on ecosystem spatial organization by addressing preservation of information integrity in upscaling/downscaling procedures of land-surface parameterization for environmental modeling applications. Scale-dependent relations of vegetation dynamics are investigated in this study by using emergent biophysical characteristics obtained through a predictive multidimensional model of vegetation anomalies derived from remote-sensing observations.

Assessing vegetation response to precipitation in northwest Morocco during the last decade: an application of MODIS NDVI and high resolution reanalysis data

Journal Articles & Books
December, 2016
Morocco

Understanding vegetation dynamics provides information on changes in land cover that can directly be related to regional changes in the climate system. In data-sparse regions, i.e. northwest Morocco studies are limited by the availability of comprehensive information on precipitation.

Upper Washita River Experimental Watersheds: Reservoir, Groundwater, and Stream Flow Data

Journal Articles & Books
December, 2014

Surface and groundwater quantity and quality data are essential in many hydrologic applications and to the development of hydrologic and water quality simulation models. We describe the hydrologic data available in the Little Washita River Experimental Watershed (LWREW) of the Southern Great Plains Research Watershed (SGPRW) and Fort Cobb Reservoir Experimental Watershed (FCREW), both located in southwest Oklahoma.

Spatial and Temporal Variability of Soil Organic Carbon in the Corn Belt of Northeastern China, 1980s–2005: A Case Study in Four Counties

Journal Articles & Books
December, 2014
China

Estimates of changes and possible causes of regional soil organic carbon (SOC) are critical for evaluation of potential responses of terrestrial biosphere to global changes. A total of 382 soil samples, collected in the 1980s from four counties in the Corn Belt of northeastern China, and of 1,514 samples collected in 2005 from the same area, were examined for SOC concentrations. Spatial and temporal SOC concentrations were evaluated after the 25-year interval using geostatistics and kriging interpolation method.

Land Ownership and Land‐Cover Change in the Southern Appalachian Highlands and the Olympic Peninsula

Journal Articles & Books
December, 1996

Social and economic considerations are among the most important drivers of landscape change, yet few studies have addressed economic and environmental influences on landscape structure, and how land ownership may affect landscape dynamics. Watersheds in the Olympic Peninsula, Washington, and the southern Appalachian highlands of western North Carolina were studied to address two questions: (1) Does landscape pattern vary among federal, state, and private lands?

model to predict stream water temperature across the conterminous USA

Journal Articles & Books
December, 2015
United States of America

Stream water temperature (tₛ) is a critical water quality parameter for aquatic ecosystems. However, tₛrecords are sparse or nonexistent in many river systems. In this work, we present an empirical model to predict tₛat the site scale across the USA. The model, derived using data from 171 reference sites selected from the Geospatial Attributes of Gages for Evaluating Streamflow database, describes the linear relationship between monthly mean air temperature (tₐ) and tₛ.

Watershed-Scale AMC Selection for Hydrologic Modeling

Journal Articles & Books
December, 2003

The Natural Resources Conservation Service curve–number (CN) method commonly uses three discrete levels (1, 2, and 3) of antecedent moisture condition (AMC) to describe soil moisture at the time of a runoff event. However, this may not adequately represent soil water conditions for watershed modeling purposes. The objectives of this study were to evaluate the use of individual–event watershed–scale AMC values to adjust field–scale CN, and to assess which hydrologic parameters would provide the best estimate of individual–event AMC.

influence of land cover composition and groundwater on thermal habitat availability for brook charr (Salvelinus fontinalis) populations in the United States of America

Journal Articles & Books
December, 2011
United States of America

- Brook charr (Salvelinus fontinalis) is a sentinel fish species that requires clean, cold water habitats generally resulting from landscapes that allow for surface water flows devoid of sediment and contaminants and high groundwater discharge of cold water. As such, brook charr are impacted by land cover changes that alter stream temperature regimes. We evaluated brook charr populations across their eastern and midwestern range in the United States with reference to thermal habitat availability in relationship to land cover and per cent baseflow.

Nitrogen isotope tracer acquisition in low and tall birch tundra plant communities: a 2� year test of the snow–shrub hypothesis

Journal Articles & Books
December, 2014

Deciduous shrub density and landcover are increasing across many areas of the Arctic. Shrub growth may be promoted by a snow–shrub feedback whereby relatively tall shrubs accumulate deeper snow, raising winter soil temperature minima, increasing microbial activity, and enhancing soil solution nitrogen (N). Although there is good evidence for the above components of the hypothesis, it has not yet been determined if shrubs can access the elevated N pool generated by deepened snow.

Land subsidence and declining water resources in Quetta Valley, Pakistan

Journal Articles & Books
December, 2013
Pakistan
Afghanistan

Extensive groundwater withdrawals in urban areas may cause water shortages, land subsidence, and water quality problems. The Quetta Valley is the largest population center in Balochistan province in western Pakistan. This area is arid and groundwater is the main water source for domestic and agricultural use. This work presents global positioning system (GPS) data and assessment of spatial and temporal variations in water levels. GPS data from two stations from mid-2006 to the beginning of 2009 show subsidence rate of 10� cm\year.