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Wyszukujesz frazę "spectral indices" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Remote sensing techniques to assess chlorophyll lfuorescence in support of crop monitoring in Poland
Autorzy:
Gurdak, Radosław
Bartold, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/1955011.pdf
Data publikacji:
2021-12-10
Wydawca:
Uniwersytet Warszawski. Wydział Geografii i Studiów Regionalnych
Tematy:
spectral vegetation indices
land surface temperature
JECAM
Sentinel satellites
Opis:
The increase in demand for food and the need to predict the impact of a warming climate on vegetation makes it critical that the best tools for assessing crop production are found. Chlorophyll fluorescence (ChlF) has been proposed as a direct indicator of photosynthesis and plant condition. The aim of this paper is to study the feasibility of estimating ChlF from spectral vegetation indices derived from Sentinel-2, in order to monitor crop stress and investigate ChlF changes in response to surface temperatures and meteorological observations. The regressions between thirty three Sentinel-2-derived VIs, and ChlF measured on the ground were evaluated in order to estimate the best predictors of ChlF. The r-Pearson correlation and polynomial linear regression were used. For maize, the highest correlation between ChlF and VIs were found for NDII (r=0.65) and for SIPI (r=-0.68). The weakest relationship between VIs and ChlF were found for sugar beets. Despite this, it should be noted that the highest correlation for sugar beets appeared for EVI (r=0.45) and S2REP (r=0.43). The results of this study indicate the need for a synergy of low and high resolution satellite data that will enable a more detailed analysis for estimating fluorescence and its relation to climatic conditions, environmental aspects, and VIs derived from satellite images.
Źródło:
Miscellanea Geographica. Regional Studies on Development; 2021, 25, 4; 226-237
0867-6046
2084-6118
Pojawia się w:
Miscellanea Geographica. Regional Studies on Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial mapping of the leaf area index using remote sensing and ground measurements – the Biebrza National Park case study
Autorzy:
Ignar, Stefan
Szporak-Wasilewska, Sylwia
Gregorczyk, Małgorzata
Powiązania:
https://bibliotekanauki.pl/articles/36062944.pdf
Data publikacji:
2023
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
leaf area index
wetlands
remote sensing
spectral vegetation indices
Biebrza
Opis:
The purpose of the described research was an attempt to estimate the leaf area index (LAI) parameter describing the structure of the vegetation based on the Landsat 5TM satellite imagery and field measurements made with the use of an optical plant canopy analyzer. The study was carried out in north-eastern Poland in the Biebrza river valley within the boundaries of the Biebrza National Park during the growing season of the year 2007. There were 13 spectral indices given in the literature known to be correlated with the LAI. The highest coefficient of determination and the highest correlation coefficient were obtained for the normalized difference vegetation index (NDVI) and the soil adjusted vegetation index (SAVI) indices for the wetland areas in the Biebrza river valley. The field measurements of the leaf area index and its spatial representation on satellite image show that the vegetation of natural river valleys is characterized by high spatial and seasonal variability. The study of the LAI on such large natural areas that are extensively used also requires knowledge of the methods of land use and the application of individual agrotechnical measures.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2023, 32, 2; 175-185
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of spectral characteristics on parameters describing CO2 exchange between crop species and the atmosphere
Autorzy:
Uździcka, Bogna
Stróżecki, Marcin
Urbaniak, Marek
Juszczak, Radosław
Powiązania:
https://bibliotekanauki.pl/articles/972951.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
spectral vegetation indices
net ecosystem
productivity
gross ecosystem productivity
crops
dynamic chambers
multispectral sensors
Opis:
The aim of this paper is to demonstrate that spectral vegetation indices are good indicators of parameters describing the intensity of CO2 exchange between crops and the atmosphere. Measurements were conducted over 2011-2013 on plots of an experimental arable station on winter wheat, winter rye, spring barley, and potatoes. CO2 fluxes were measured using the dynamic closed chamber system, while spectral vegetation indices were determined using SKYE multispectral sensors. Based on spectral data collected in 2011 and 2013, various models to estimate net ecosystem productivity and gross ecosystem productivity were developed. These models were then verified based on data collected in 2012. The R2 for the best model based on spectral data ranged from 0.71 to 0.83 and from 0.78 to 0.92, for net ecosystem productivity and gross ecosystem productivity, respectively. Such high R2 values indicate the utility of spectral vegetation indices in estimating CO2 fluxes of crops. The effects of the soil background turned out to be an important factor decreasing the accuracy of the tested models.
Źródło:
International Agrophysics; 2017, 31, 3
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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