نتایج جستجو برای: vegetation cover maps
تعداد نتایج: 249983 فیلتر نتایج به سال:
The vegetation outlook (VegOut) is a geospatial tool for predicting general vegetation condition patterns across large areas. VegOut predicts a standardized seasonal greenness (SSG) measure, which represents a general indicator of relative vegetation health. VegOut predicts SSG values at multiple time steps (two to six weeks into the future) based on the analysis of “historical patterns” (i.e.,...
The factors that influence tephra layer taphonomy are poorly understood, but vegetation cover is likely to play a role in the preservation of terrestrial tephra deposits. The impact of vegetation on tephra layer preservation is important because: 1) the morphology of tephra layers could record key characteristics of past land surfaces and 2) vegetation-driven variability in tephra thickness cou...
Field surveys often show that high water turbidity limits cover of aquatic vegetation, while many small-scale experiments show that vegetation can reduce turbidity by decreasing water flow, stabilizing sediments, and competing with phytoplankton for nutrients. Here we bridged these two views by exploring the direction and strength of causal relationships between aquatic vegetation and turbidity...
the aim of this study was to investigate relationships between soil properties and plant species to determine the most effective factors separating vegetation communities in rineh rangeland. three stratifying variables were selected including slop, aspect and elevation. the study area was partitioned by combining these classes to generate homogenous units. 1m2 quadrates were located at sampling...
We investigate the response of a climate system model to two different methods for estimating snow cover fraction. In the control case, snow cover fraction changes gradually with snow depth; in the alternative scenarios (one with prescribed vegetation and one with dynamic vegetation), snow cover fraction initially increases with snow depth almost twice as fast as the control method. In cases wh...
In Australia, remotely sensed Landsat TM data is routinely used for mapping and monitoring the change in extent of woody perennial vegetation cover providing information for conservation, land management and for modelling carbon flux and water use. For a variety of reasons including land cover definitions and sensor spectral limitations, studies have tended to focus on reporting changes in land...
Detecting land cover change over semi-arid rangeland is important for monitoring vegetation responses to drought, population expansion, and changing agricultural practices. Such change can be detected using vegetation indices, but these do not represent non-green vegetation and are dominated by seasonal changes. An alternative is to observe spatial changes in thermal emissivities, a measure tha...
negative impacts of gully erosion in marly areas are severe due to improper landuse practices such as irrigation, tillage, overgrazing and degradation of vegetation cover. the objective of this research was to evaluate gully thresholds related to plant vegetation cover and landuse change in the agriculture (ag), fair rangeland (fr) and weak rangeland (wr) areas of ghaasr-e-shirin, kermanshah, i...
the aim of this study was providing plant species predictive habitat models by using logisticregression method. for this purpose, study area conducted in north east rangelands of semnanmodeling vegetation data in addition to site condition in formation including topography, and soil wasprepared. sampling was done within each unit of sampling parallel transects and 1 vertical transectwith 750m l...
It is generally believed that there is an inverse relationship between population growth and vegetation cover. However, reports about vegetation protection and reforestation around the World have been continuously increasing in recent decades, which seems to indicate that this relationship may not be true. In this paper, we have taken 21 cities in Guangdong Province, China as the study area to ...
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