scholarly journals Using Satellite-Borne Remote Sensing Data in Generating Local Warming Maps with Enhanced Resolution

2018 ◽  
Vol 7 (10) ◽  
pp. 398 ◽  
Author(s):  
Khan Rubayet Rahaman ◽  
M. Razu Ahmed ◽  
Quazi K. Hassan

Warming, i.e., increments of temperature, is evident at the global, regional, and local level. However, understanding the dynamics of local warming at high spatial resolution remains challenging. In fact, it is very common to see extremely variable land cover/land use within built-up environments that create micro-climatic conditions. To address this issue, our overall goal was to generate a local warming map for the period 1961–2010 at 15 m spatial resolution over the southern part of the Canadian province of Alberta. Our proposed methods consisted of three distinct steps. These were the: (i) construction of high spatial resolution enhanced vegetation index (EVI) and normalized difference vegetation index (NDVI) maps; (ii) conversion of air temperature (Ta) normal (i.e., 30 years average) at higher spatial resolution using vegetation indices (VI); and (iii) generation of a local warming map at 15m spatial resolution. In order to execute this study, we employed MODIS-driven air temperature data, EVI and NDVI data, and Landsat-driven vegetation indices. The study uncovered that around 58% (up to positive 1 °C) of areas in the considered study region were experiencing increased temperature; whereas only about 4% of areas underwent a cooling trend (more than negative 0.25 °C). The remaining 38% did not exhibit significant change in temperature. We concluded that remote sensing technology could be useful to enhance the spatial resolution of local warming maps, which would be useful for decision-makers considering efficient decisions in the face of increments in local temperature.

2017 ◽  
Vol 35 (1) ◽  
pp. 82-91
Author(s):  
Cesar Edwin García ◽  
David Montero ◽  
Hector Alberto Chica

The main objective of the research carried out in the sugar productive sector in Colombia is to improve crop productivity of sugarcane. The rise of RPAS, together with the use of multispectral cameras, which allows for high spatial resolution images and spectral information outside the visible spectrum, has generated an alternative nondestructive technological approach to monitoring crop sugarcane that must be evaluated and adapted to the specific conditions of Colombia's sugar productive sector. In this context, this paper assesses the potential of a modified camera (NIR) to discriminate three varieties of sugarcane, as well as three doses of fertilization and estimating the sugarcane yield at an early stage, for the three varieties through multiple vegetation indices. In this study, no significant differences were found by vegetation index between fertilization doses, and only significant differences between varieties were found when the fertilization was normal or high. Likewise, multiple regressions between scores derived from vegetation indices after applying PCA and productivity produced determinations of up to 56%.


2020 ◽  
Vol 40 (10) ◽  
pp. 1028001
Author(s):  
陈世涵 Chen Shihan ◽  
李玲 Li Ling ◽  
蒋弘凡 Jiang Hongfan ◽  
居伟杰 Ju Weijie ◽  
张曼玉 Zhang Manyu ◽  
...  

2021 ◽  
Vol 13 (14) ◽  
pp. 2674
Author(s):  
Tingting Lv ◽  
Xiang Zhou ◽  
Zui Tao ◽  
Xiaoyu Sun ◽  
Jin Wang ◽  
...  

Remote sensing (RS)-derived vegetation indices (VIs) with medium and high spatial resolution have emerged as a promising dataset for fine-scale ecosystem modeling and agricultural monitoring at local or global scales. Before they can be used as reliable inputs for other research, conducting in situ measurements for validation is very critical. However, the spatial heterogeneity due to the diversity of land cover and its spatial organization in the landscape increases the uncertainty of validation, so design of optimal sampling is an important basis for the reliability of the validation. In this paper, we propose an integrative stratified sampling strategy (INTEG-STRAT) based on normalized difference vegetation index (NDVI) data as prior knowledge. The basic idea is to realize a sampling optimization by determining the optimal combination of the spatial sampling method (e.g., simple random sampling (SRS), spatial system sampling (SYS), stratified sampling, generalized random tessellation stratified (GRTS), balanced acceptance sampling (BAS)) and spatial stratification scheme with an objective rule. The objective rule in this paper is to minimize the root mean square error (RMSE) of 10-fold cross validation between estimated values (sample are not included) and the corresponding values on prior knowledge. Relative precision, correlation coefficient, and RMSE are used to compare the effectiveness of the proposed sampling strategy with each sampling method without considering sampling optimization. After comparing, we find that the INTEG-STRAT requires fewer samples to become stable and has higher accuracy. At site 1, when the correlation coefficient between NDVI image and the simulated NDVI surface reached 80%, INTEG-STRAT needed only 70 sampling points while other methods require more sampling points. At the same time, INTEG-STRAT strategy has a smaller RMSE between the estimated values and the corresponding values on prior knowledge image. In general, INTEG-STRAT is an effective method in the selection of representative samples to support the validation of vegetation indices products with medium and high spatial resolution.


2021 ◽  
Vol 36 (1) ◽  
pp. 111-122
Author(s):  
Felipe de Souza Nogueira Tagliarini ◽  
Mikael Timóteo Rodrigues ◽  
Bruno Timóteo Rodrigues ◽  
Yara Manfrin Garcia ◽  
Sérgio Campos

IMAGENS DE VEÍCULO AÉREO NÃO TRIPULADO APLICADAS NA OBTENÇÃO DO ÍNDICE DE VEGETAÇÃO POR DIFERENÇA NORMALIZADA   FELIPE DE SOUZA NOGUEIRA TAGLIARINI1, MIKAEL TIMÓTEO RODRIGUES2-3, BRUNO TIMÓTEO RODRIGUES1; YARA MANFRIN GARCIA1 E SÉRGIO CAMPOS1   1 Departamento de Engenharia Rural, Faculdade de Ciências Agronômicas (FCA) - Universidade Estadual Paulista (UNESP), Avenida Universitária, nº 3780, Altos do Paraíso, CEP: 18610-034, Botucatu, São Paulo, Brasil. E-mail: [email protected]; [email protected]; [email protected]; [email protected] 2 Centro Universitário Dinâmica das Cataratas (UDC), Rua Castelo Branco, nº 440, Centro, CEP: 85852-010, Foz do Iguaçu, Paraná, Brasil. E-mail: [email protected] 3 Parque Tecnológico Itaipu (PTI), Avenida Tancredo Neves, nº 6731, Jardim Itaipu, Caixa Postal: 2039, CEP: 85867-900, Foz do Iguaçu, Paraná, Brasil. E-mail: [email protected].   RESUMO: O advento dos Veículos Aéreos Não Tripulados (VANT) como ferramenta no sensoriamento remoto possibilitou uma plataforma atuante em diferentes áreas para o mapeamento com elevada precisão e resolução. O objetivo deste estudo consistiu na análise do Índice de Vegetação por Diferença Normalizada (NDVI) para elaboração de mapa temático por meio de aerofotogrametria e fotointerpretação, com maior detalhamento da vegetação devido à altíssima resolução espacial alcançada com o uso de imagens coletadas por VANT em trecho do rio Lavapés, dentro dos limites da Fazenda Experimental Lageado no município de Botucatu-SP. As imagens foram obtidas por meio dos sensores MAPIR Survey3W RGB e Survey3W NIR/InfraRED, embarcados em VANT multirrotor 3DR SOLO. Para construção dos ortomosaicos RGB e NDVI, as imagens foram processadas no software Pix4Dmapper 3.0. O resultado do NDVI proporcionou transição bem nítidas entre os alvos bióticos (vegetação) e os alvos abióticos (corpo d'água, solo e edificações), e também entre a própria vegetação, possibilitando a distinção da vegetação de porte arbóreo, com maior vigor vegetativo, em relação a vegetação de porte herbáceo. As imagens com elevada resolução espacial coletadas por VANT, demonstraram flexibilidade de utilização, possuindo elevado potencial para o mapeamento de dinâmica da paisagem e a resposta espectral da vegetação.   Palavras-chaves: drone, índice radiométrico, sensoriamento remoto   IMAGES OF UNMANNED AERIAL VEHICLE APPLIED TO OBTAIN THE NORMALIZED DIFFERENCE VEGETATION INDEX   ABSTRACT: The advent of Unmanned Aerial Vehicle (UAV) as a tool in remote sensing has enabled a platform acting in different areas for mapping with high precision and resolution. This study aimed to analyze the Normalized Difference Vegetation Index (NDVI) for the elaboration of thematic map through aerophotogrammetry and photointerpretation, with greater detail of vegetation due to high spatial resolution achieved with the use of images collected by UAV in a stretch of Lavapés river, inside the domains of Lageado Experimental Farm in the municipality of Botucatu-SP. The images were obtained through MAPIR Survey3W RGB and Survey3W NIR/InfraRED sensors, aboard a 3DR SOLO multirotor UAV. For constructing RGB and NDVI orthomosaics, the images were processed using Pix4Dmapper 3.0 software. The NDVI result provided a clear transition among biotic targets (vegetation) and abiotic targets (water, soil and buildings), and among the vegetation itself, with greater vegetative vigor, making possible the distinction of arboreal vegetation, in relation to herbaceous vegetation. The images with high spatial resolution collected by UAV demonstrated the flexibility of use, having high potential to mapping landscape dynamics and the spectral response of vegetation.   Keywords: drone, radiometric index, remote sensing.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 286
Author(s):  
Sang-Jin Park ◽  
Seung-Gyu Jeong ◽  
Yong Park ◽  
Sang-hyuk Kim ◽  
Dong-kun Lee ◽  
...  

Climate change poses a disproportionate risk to alpine ecosystems. Effective monitoring of forest phenological responses to climate change is critical for predicting and managing threats to alpine populations. Remote sensing can be used to monitor forest communities in dynamic landscapes for responses to climate change at the species level. Spatiotemporal fusion technology using remote sensing images is an effective way of detecting gradual phenological changes over time and seasonal responses to climate change. The spatial and temporal adaptive reflectance fusion model (STARFM) is a widely used data fusion algorithm for Landsat and MODIS imagery. This study aims to identify forest phenological characteristics and changes at the species–community level by fusing spatiotemporal data from Landsat and MODIS imagery. We fused 18 images from March to November for 2000, 2010, and 2019. (The resulting STARFM-fused images exhibited accuracies of RMSE = 0.0402 and R2 = 0.795. We found that the normalized difference vegetation index (NDVI) value increased with time, which suggests that increasing temperature due to climate change has affected the start of the growth season in the study region. From this study, we found that increasing temperature affects the phenology of these regions, and forest management strategies like monitoring phenology using remote sensing technique should evaluate the effects of climate change.


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