نتایج جستجو برای: vegetation index
تعداد نتایج: 435690 فیلتر نتایج به سال:
Information about an area and its distribution of planted and harvested paddy rice field is essential for food security management, water resource management, and for the estimation of gas emissions. Rice field has specific coverage characteristics throughout its life time. Its coverage is mixed proportionally in accordance with its age, between water, soil, and rice vegetation. Landsat ETM+ ha...
In recent years, a close link between vegetation change and climate change has been established. Vegetation change can be detected with remotely sensed images, especially with normalized difference vegetation index time series records. We used change vector analysis, especially change vector magnitude (CV magnitude), as an indicator to better understand vegetation change. Twenty-one layers of C...
Current high spatial resolution satellite sensors lack the spectral resolution required for many quantitative remote sensing applications and, given the limited spectral resolution, they only allow the calculation of a limited number of vegetation indices and remote sensing products. Additionally if short revisit time is required for management applications, the cost of high resolution imagery ...
Unmanned Aerial Vehicles (UAV)-based remote sensing offers great possibilities to acquire in a fast and easy way field data for precision agriculture applications. This field of study is rapidly increasing due to the benefits and advantages for farm resources management, particularly for studying crop health. This paper reports some experiences related to the analysis of cultivations (vineyards...
Multiple endmember spectral mixture analysis (MESMA) has been widely applied for estimating fractional land covers from remote sensing imagery. MESMA has proven effective in addressing inter-class and intra-class endmember variability by allowing pixel-specific endmember combinations. This method, however, assumes that each land cover type has an equal probability of being included in the model...
[1] Lateral water flow in catchments can produce important patterns in water and nutrient fluxes and stores and also influences the long-term spatial development of forest ecosystems. Specifically, patterns of vegetation type and density along hydrologic flow paths can represent a signal of the redistribution of water and nitrogen mediated by lateral hydrologic flow. This study explores the use...
Drought is expected to increase in frequency and severity due to global warming, and its impacts on vegetation are typically extensively evaluated with climatic drought indices, such as multi-scalar Standardized Precipitation Evapotranspiration Index (SPEI). We analyzed the covariation between the SPEIs of various time scales and the anomalies of the normalized difference vegetation index (NDVI...
Ž In the last two decades, numerous investigators have proposed cumulative vegetation indices i.e., functions which . encode the cumulative effect of NDVI maximum value composite time-series into a single variable for net primary Ž . productivity NPP mapping and monitoring on a regional to continental basis. In this paper, we investigate the relationships among three of the most commonly used c...
Monitoring the post-burn recovery condition of chaparral vegetation in southern California is important for managers to determine the appropriate time to conduct controlled burns. Due to the di culty of monitoring post-® re recovery over large areas and the absence of detailed ® re records in many areas, we examined the possibility of using satellite observations to establish the post® re reco...
A land surface vegetation index, defined as the difference of microwave land surface emissivity at 19 and 37 GHz, was calculated for a heavily forested area in north central Massachusetts. The microwave emissivity difference vegetation index (EDVI) was estimated from satellite SSM/I measurements at the defined wavelengths and used to estimate land surface turbulent fluxes. Narrowband visible an...
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