نتایج جستجو برای: modis و avhrr
تعداد نتایج: 768857 فیلتر نتایج به سال:
The measurement of sea surface temperature (SST) is utmost importance in the realm oceanography. increasing utilization satellite data SST research has highlighted crucial need to compare and evaluate various sources. Using iQuam2 situ data, this study aims assess accuracy datasets obtained from three polar-orbiting satellites (AVHRR, Modis-Aqua, Modis-Terra) one geostationary (Himawari-8) Boha...
Abstract Alaska’s Yukon–Kuskokwim Delta (YKD) is among the Arctic’s warmest, most biologically productive regions, but regional decline of normalized difference vegetation index (NDVI) has been a striking feature spaceborne Advanced High Resolution Radiometer (AVHRR) observations since 1982. This contrast with “greening” prevalent elsewhere in low Arctic raises questions concerning climatic and...
Vegetation phenology is the chronology of periodic phases of development. It constitutes an efficient bio-indicator of impacts of climate changes and a key parameter for understanding and modelling vegetation-climate interactions and their implications on carbon cycling. Numerous studies were devoted to the remote sensing of vegetation phenology. Most of these were carried out using data acquir...
The Normalized Difference Vegetation Index (NDVI) time-series data derived from Advanced Very High Resolution Radiometer (AVHRR) have been extensively used for studying inter-annual dynamics of global and regional vegetation. However, there can be significant uncertainties in the data due to incomplete atmospheric correction and orbital drift of the satellites through their active life. Access ...
Abstract The Advanced Very High Resolution Radiometers (AVHRR), which have been flying on National Oceanic and Atmospheric Administration’s (NOAA) polar-orbiting weather satellites since 1978, provide the longest global record of Earth observations from a visible–infrared imager. Experience gained through AVHRRs has integral to development new-generation sensors such as Moderate Imaging Spectro...
Analysis of the Phenology in the Mongolian Plateau by Inter-Comparison of Global Vegetation Datasets
This study evaluates the performances of three global satellite datasets (Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Satellite pour l’ observation de la Terre (SPOT) of the Mongolian Plateau, where in situ observation is insufficient to assess vegetation dynamics on terrestrial systems. We give a comprehensive assessment of the hi...
Accurately modeling the land surface phenology based on satellite data is very important to the study of vegetation ecological dynamics and the related ecosystem process. In this study, we developed a Sigmoid curve (S-curve) function by integrating an asymmetric Gaussian function and a logistic function to fit the leaf area index (LAI) curve. We applied the resulting asymptotic lines and the cu...
Past studies of the NOAA AVHRR/2 and GOES I-M imagery (e.g., Setvák et al., 1996) have shown that frozen tops of deep convective storms occasionally exhibit significant increase of cloud top reflectivity when observed in the 3.7 or 3.9 μm spectral bands. Similar storm top features have been documented in the NOAA-KLM AVHRR/3 1.6 μm spectral band (Setvák et al., 2003). Consequently, cross-compar...
On the basis of AVHRR GIMMS NDVI and MODIS NDVI, we constructed monthly NDVI sequences covering Northeast China from 1982 to 2009 using a per-pixel unary linear regression model. The expanded NDVI passed the consistency check and were well used for analysis. The monthly NDVI trends were highly correlated with climatic changes. Spatially averaged NDVI in summer exhibited a downward trend with
This study introduces a new geographic framework, phenological classification, for the conterminous United States based on Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) time-series data and a digital elevation model. The resulting pheno-class map is comprised of 40 phenoclasses, each having unique phenological and topographic characteristics...
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