Canopy leaf area index (LAI) is an important structural parameter of the vegetation controlling pollutant uptake by terrestrial ecosystems. This paper presents a computationally efficient algorithm for retrieval of vegetation LAI and canopy clumping factor from satellite data using observed Simple Ratios (SR) of near-infrared to red reflectance. The method employs numerical inversion of a physics-based analytical canopy radiative transfer model that simulates the bi-directional reflectance distribution function (BRDF). The algorithm is independent of ecosystem type. The method is applied to 1-km resolution AVHRR satellite images to retrieve a geo-referenced data set of monthly LAI values for the conterminous USA. Satellite-based LAI estimates are compared against independent ground LAI measurements over a range of ecosystem types. Verification results suggest that the new algorithm represents a viable approach to LAI retrieval at continental scale, and can facilitate spatially explicit studies of regional pollutant deposition and trace gas exchange.
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http://dx.doi.org/10.1016/j.envpol.2005.08.059 | DOI Listing |
Soil moisture is a key parameter for the exchange of substance and energy at the land-air interface, timely and accurate acquisition of soil moisture is of great significance for drought monitoring, water resource management, and crop yield estimation. Synthetic aperture radar (SAR) is sensitive to soil moisture, but the effects of vegetation on SAR signals poses challenges for soil moisture retrieval in areas covered with vegetation. In this study, based on Sentinel-1 SAR and Sentinel-2 optical remote sensing data, a coupling approach was employed to retrieval surface soil moisture over dense vegetated areas.
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December 2024
School of Biological and Environmental Sciences, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK.
Camera traps offer enormous new opportunities in ecological studies, but current automated image analysis methods often lack the contextual richness needed to support impactful conservation outcomes. Integrating vision-language models into these workflows could address this gap by providing enhanced contextual understanding and enabling advanced queries across temporal and spatial dimensions. Here, we present an integrated approach that combines deep learning-based vision and language models to improve ecological reporting using data from camera traps.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Indian Institute of Technology, Madras, Chennai, Tamil Nadu, India.
Rapid urbanization has altered land use and land cover to accommodate the growing population. This shift towards urbanization has resulted in the UHI effect, where the inner urban core is notably warmer than its surroundings. Existing research on UHI has primarily focused on major cities at the regional scale, leaving a gap in addressing the effect of extreme UHI zones within a city.
View Article and Find Full Text PDFPlants (Basel)
November 2024
State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Timely and accurate monitoring of above-ground biomass (AGB) is of great significance for indicating crop growth status, predicting yield, and assessing carbon dynamics. Compared with the traditional time-consuming and laborious method through destructive sampling, UAV remote sensing provides a timely and efficient strategy for estimating biomass. However, the universality of remote sensing retrieval models with multi-feature fusion under different management practices and cultivars are unknown.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
Department of Water Resource Development & Management, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India, 247667.
The accurate retrieval of soil moisture plays a pivotal role in agriculture, particularly in effective irrigation water management, as it significantly affects crop growth and yield. The present study mainly focuses on the robustly investigated capability of dual-polarized Sentinel-1 SAR-derived vegetation descriptors in the water cloud model (WCM) in surface soil moisture (SSM) retrieval over wheat crops. The vegetation descriptors used in the study are radar vegetation index (RVI), backscattering ratio, polarimetric radar vegetation index (PRVI), dual polarization SAR vegetation index (DPSVI), and dual polarimetric radar vegetation index (DpRVI).
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