نتایج جستجو برای: vegetation index
تعداد نتایج: 435690 فیلتر نتایج به سال:
Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 t...
Nairobi, Kenya exhibits a wide variety of micro-climates and heterogeneous surfaces. Paved roads and high-rise buildings interspersed with low vegetation typify the central business district, while large neighborhoods of informal settlements or "slums" are characterized by dense, tin housing, little vegetation, and limited access to public utilities and services. To investigate how heat varies ...
This paper reports the passive microwave radiometry application for regional assessment of crop growth in India. Brightness temperature (TB) of various vegetation classes observed at 37 GHz using special sensor microwave imager (SSMI) data. during Kharif season in 1 999 in India are analyzed. Vertical as well as hQrizontal polarization brightness temperature is used to derive microwave polariza...
Coverage rates of vegetation and exposed bedrock are two key indicators of karst rocky desertification. In this study, the abundances of vegetation and exposed rock were retrieved from a hyperspectral Hyperion image using linear spectral unmixing method. The results were verified using the spectral indices of karst rocky desertification (KRDSI) and an integrated LAI spectral index: modified chl...
Measurements of carbon ̄ uxes in Arctic tundra landscapes are generally obtained through intensive ® eld work and involve the use of chamber and/or micrometeorological tower techniques. However, ® ndings in a variety of nonArctic ecosystems have demonstrated the potential of remote sensing-based techniques (particularly spectral vegetation indices) to provide estimates of CO2 exchange in amore ...
Long-term global datasets of the Leaf Area Index (LAI) are important for monitoring global vegetation dynamics and are an important input for Earth system models (ESM). The comparison of long-term datasets is based on two recently available datasets both derived from AVHRR (Advanced Very High Resolution Radiometer) time series. The LAI3g dataset is developed from the new improved third generati...
Determining the potential of soil seed bank and its specific species is important for conservation goals and vegetation restoration of rangelands. In this study, the characteristics of soil seed bank and standing vegetation in Lazour mountain rangeland were investigated in order to estimate the rehabilitation ability of the study area in case of possible disturbances. In order to determine the ...
The SIGRI (Sistema Integrato per la Gestione del Rischio Incendi) pilot project, funded by ASI (the Italian Space Agency), aims at developing an Integrated System for the Management of the Wild Fire Events. The system should provide satellite based products capable of assisting all the phases of the fire contrasting activities: prevision, detection, and damage assessment/recovering. This paper ...
Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes > 35 N. Two distinct periods of increasing plant growth were apparent: 1982 to 1991 and 1992 to 1999, separated by a reduction from 1991 to 199...
The Qinghai-Tibetan Plateau (QTP) contains the largest permafrost area in a high-altitude region in the world, and the unique hydrothermal environments of the active layers in this region have an important impact on vegetation growth. Geographical locations present different climatic conditions, and in combination with the permafrost environments, these conditions comprehensively affect the loc...
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