James Malcher , David Robertson , Galen Holt , Rebecca E. Lester
{"title":"Quantification and attribution of spectral variation in irrigated perennial tree crops","authors":"James Malcher , David Robertson , Galen Holt , Rebecca E. Lester","doi":"10.1016/j.rsase.2025.101524","DOIUrl":null,"url":null,"abstract":"<div><div>Satellite reflectance data are used for crop classification models globally, yet research on their robustness under varying temporal and spatial conditions is limited. We examined the effects of space, time, water availability and ontogeny on crop spectral distributions cross a large, heterogenous landscape, Australia's Murray-Darling Basin. We aimed for broad generality of our findings, and so used a large ground-truthed dataset from 2015, 2018, and 2021, covering multiple catchments and 12 crops. We characterised spectral distributions for each crop in each year and catchment before testing for differences due to space and time, and associated with the amount of water available from irrigation and rainfall. We also tested bareness metrics (as a surrogate for perennial crop ages) in almond plantations. We found that crop type explained the most variation, confirming the utility of satellite imagery for crop classification. Catchment and year both explained small but significant variation, emphasising the need for data collected over a range of spatial and temporal contexts. Water availability explained a significant but small proportion of variation in the data set (<1 %), suggesting that crops were receiving sufficient water across the observed range or that spectral signatures did not vary much as a result. The effect of bareness metrics suggested possible significant variation caused by ontogeny. This study affirms the validity of spectral imagery for crop classification studies, whilst underscoring the importance of spatial, hydrologic and ontogenetic context. Future studies in crop classification should consider these factors to enhance the robustness of their models.</div></div>","PeriodicalId":53227,"journal":{"name":"Remote Sensing Applications-Society and Environment","volume":"38 ","pages":"Article 101524"},"PeriodicalIF":3.8000,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Remote Sensing Applications-Society and Environment","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2352938525000771","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Satellite reflectance data are used for crop classification models globally, yet research on their robustness under varying temporal and spatial conditions is limited. We examined the effects of space, time, water availability and ontogeny on crop spectral distributions cross a large, heterogenous landscape, Australia's Murray-Darling Basin. We aimed for broad generality of our findings, and so used a large ground-truthed dataset from 2015, 2018, and 2021, covering multiple catchments and 12 crops. We characterised spectral distributions for each crop in each year and catchment before testing for differences due to space and time, and associated with the amount of water available from irrigation and rainfall. We also tested bareness metrics (as a surrogate for perennial crop ages) in almond plantations. We found that crop type explained the most variation, confirming the utility of satellite imagery for crop classification. Catchment and year both explained small but significant variation, emphasising the need for data collected over a range of spatial and temporal contexts. Water availability explained a significant but small proportion of variation in the data set (<1 %), suggesting that crops were receiving sufficient water across the observed range or that spectral signatures did not vary much as a result. The effect of bareness metrics suggested possible significant variation caused by ontogeny. This study affirms the validity of spectral imagery for crop classification studies, whilst underscoring the importance of spatial, hydrologic and ontogenetic context. Future studies in crop classification should consider these factors to enhance the robustness of their models.
期刊介绍:
The journal ''Remote Sensing Applications: Society and Environment'' (RSASE) focuses on remote sensing studies that address specific topics with an emphasis on environmental and societal issues - regional / local studies with global significance. Subjects are encouraged to have an interdisciplinary approach and include, but are not limited by: " -Global and climate change studies addressing the impact of increasing concentrations of greenhouse gases, CO2 emission, carbon balance and carbon mitigation, energy system on social and environmental systems -Ecological and environmental issues including biodiversity, ecosystem dynamics, land degradation, atmospheric and water pollution, urban footprint, ecosystem management and natural hazards (e.g. earthquakes, typhoons, floods, landslides) -Natural resource studies including land-use in general, biomass estimation, forests, agricultural land, plantation, soils, coral reefs, wetland and water resources -Agriculture, food production systems and food security outcomes -Socio-economic issues including urban systems, urban growth, public health, epidemics, land-use transition and land use conflicts -Oceanography and coastal zone studies, including sea level rise projections, coastlines changes and the ocean-land interface -Regional challenges for remote sensing application techniques, monitoring and analysis, such as cloud screening and atmospheric correction for tropical regions -Interdisciplinary studies combining remote sensing, household survey data, field measurements and models to address environmental, societal and sustainability issues -Quantitative and qualitative analysis that documents the impact of using remote sensing studies in social, political, environmental or economic systems