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Quantifying local fire regimes using the Landsat data-archive:a conceptual framework to derive detailed fire pattern metrics from pixel-level information

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International Journal of Digital Earth 2019年第5期12卷 544-565页

作者： Ignacio San-Miguel David W.Andison nicholas c.coops Integrated Remote Sensing Studio Department of Forest Resources ManagementUniversity of British ColumbiaVancouverBCCanada Bandaloop Landscape-Ecosystem Services North VancouverBCCanada

Free and open access to the Landsat archive has enabled the detection and delineation of an unprecedented number of fire events across the *** the availability and potential of these data,few studies have analysed residual vegetation patterns and/or partial mortality of fire across the canadian boreal forest,and those available,are either incomplete or ***,they all differ in the methods and spatial language,which makes it difficult for managers to interpret fire patterns over large *** is an urgent need for methods to help unify fire pattern observations across the canadian boreal *** study explores the capacity of the Landsat data archive when coupled with a recently developed fire mapping approach and a robust spatial language to characterize and compare tree mortality patterns across the boreal plains ecozone,*** 507 fires 2.5 Mha mapped,this study represents the most comprehensive analysis of mortality patterns for study *** from this demonstration generated an accurate characterization of the fire patterns the various ecoregions based on seven key fire *** comparison between ecoregions revealed differences in the amount of residual vegetation,which in turn suggested various climate,topography and/or vegetation ecosystem drivers.

关键词： Fire emulation historical range of variability landscape metrics fire patterns disturbance-based management

Mapping tree canopies in urban environments using airborne laser scanning (ALS):a Vancouver case study

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Forest Ecosystems 2018年第4期5卷 429-437页

作者： Giona Matasci nicholas c.coops David A.R.Williams Nick Page Department of Forest Resource Management Unlversity of British Columbia2424Main MallVancouverBC V6T IZ4Canada Vancouver Board of Parks and Recreation 2099Beach AvenueVancouverBC V6G IZ4Canada

Background: The distribution of forest vegetation within urban environments is critically important as it influences urban environmental conditions and the energy exchange through the absorption of solar radiation and modulation of evapotranspiration. It also plays an important role filtering urban water systems and reducing storm water ***: We investigate the capacity of ALS data to individually detect, map and characterize large(taller than15 m) trees within the city of Vancouver. Large trees are critical for the function and character of Vancouver’s urban forest. We used an object-based approach for individual tree detection and segmentation to determine tree locations(position of the stem), to delineate the shape of the crowns and to categorize the latter either as coniferous or ***: Results indicate a detection rate of 76.6% for trees > 15 m with a positioning error of 2.11 m(stem location). Extracted tree heights possessed a RMSE of 2.60 m and a bias of-1.87 m, whereas crown diameter was derived with a RMSE of 3.85 m and a bias of-2.06 m. Missed trees are principally a result of undetected treetops occurring in dense, overlapping canopies with more accurate detection and delineation of trees in open ***: By identifying key structural trees across Vancouver’s urban forests, we can better understand their role in providing ecosystem goods and services for city residents.

关键词： Urban forest Large trees Light detection and ranging Airborne laser scanning

characterization of spatial relationships between three remotely sensed indirect indicators of biodiversity and climate:a 21years’data series review across the canadian boreal forest

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International Journal of Digital Earth 2016年第7期9卷 676-696页

作者： Liliana Perez Trisalyn Nelson nicholas c.coops Fabio Fontana c.Ronnie Drever Laboratory of Environmental Geosimulation(LEDGE) Department of GeographyUniversity of MontrealMontrealQCCanada Spatial Pattern Analysis&Research(SPAR)Lab Department of GeographyUniversity of VictoriaVictoriaBCCanada Department of Forest Resources Management University of British ColumbiaVancouverBCCanada The Nature conservancy OttawaONCanada

climate drives ecosystem processes and impacts *** patterns over large areas,such as canada’s boreal,can be monitored using indirect indicators derived from remotely sensed *** this paper,we characterized the historical space–time relationships between climate and a suite of indirect indicators of biodiversity,known as the Dynamic Habitat Index(DHI)to identify where climate variability is co-occurring with changes in biodiversity *** represented biodiversity using three indirect indicators generated from 1987 to 2007 National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer *** quantifying and clustering temporal variability in climate data,we defined eight homogeneous climate variability zones,where we then analyzed the *** identified unique areas of change in climate,such as the Hudson Plains,that explain significant variations in *** variability in temperatures and growing season index had a strong influence on observed vegetation productivity and seasonality changes throughout canada’s *** in precipitation,for most of the area,was not associated with DHI *** methodology presented here enables assessment of spatial–temporal relationships between biodiversity and climate variability and characterizes distinctive zones of variation that may be used for prioritization and planning to ensure long-term biodiversity conservation in canada.

关键词： climate change biodiversity boreal forest spatial–temporal analysis fPAR DHI

Satellite-observed changes in terrestrial vegetation growth trends across the Asia-Pacific region associated with land cover and climate from 1982 to 2011

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International Journal of Digital Earth 2016年第11期9卷 1055-1076页

作者： Baozhang chen Guang Xu nicholas c.coops Philippe ciais Ranga B.Myneni Key Laboratory of Soil and Water conservation and Desertification combating Ministry of EducationBeijing Forestry UniversityBeijingPeople’s Republic of China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhouPeople’s Republic of China Jiangsu center for collaborative Innovation in Geographic Information Resource Development and Application NanjingPeople’s Republic of China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China University of chinese Academy of Sciences BeijingPeople’s Republic of China Department of Forest Resource Management University of British ColumbiaVancouverBCCanada Laboratoire des Sciences du climat et de l’Environnement UnitéMixte de Recherche Commissariatàl’Energie AtomiqueCentre National de la Recherche ScientifiqueUniversitéde Versailles Saint-Quentin-en-YvelinesGif-sur-YvetteFrance Department of Earth and Environment Boston UniversityBostonMAUSA

The Asia-Pacific(AP)region has experienced faster warming than the global average in recent decades and has experienced more climate extremes,however little is known about the response of vegetation growth to these *** updated Global Inventory Modeling and Mapping Studies third-generation global satellite Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index dataset and gridded reanalysis climate data were used to investigate the spatiotemporal changes in both trends of vegetation dynamic indicators and climatic *** then further analyzed their relations associated with land cover across the AP *** main findings are threefold:(1)at continental scales the AP region overall experienced a gradual and significant increasing trend in vegetation growth during the last three decades,and this NDVI trend corresponded with an insignificant increasing trend in temperature;(2)vegetation growth was negatively and significantly correlated with the Pacific Decadal Oscillation index and the El Niño/Southern Oscillation(ENSO)in AP;and(3)at pixel scales,except for Australia,both vegetation growth and air temperature significantly increased in the majority of study regions and vegetation growth spatially correlated with temperature;In Australia and other water-limited regions vegetation growth positively correlated with precipitation.

关键词： Vegetation dynamics NDVI climate change land cover Asia-Pacific region

Mass data processing of time series Landsat imagery:pixels to data products for forest monitoring

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International Journal of Digital Earth 2016年第11期9卷 1035-1054页

作者： Txomin Hermosilla Michael A.Wulder Joanne c.White nicholas c.coops Geordie W.Hobart Lorraine B.campbella Integrated Remote Sensing Studio Department of Forest Resources ManagementUniversity of British ColumbiaVancouverBCCanada canadian Forest Service(Pacific Forestry centre) Natural Resources CanadaVictoriaBCCanada

Free and open access to the Landsat archive has enabled the implementation of national and global terrestrial monitoring ***,we summarize a project characterizing the change history of canada’s forested ecosystems with a time series of data representing *** the composite2change approach,we applied spectral trend analysis to annual best-available-pixel(BAP)surface reflectance image composites produced from Landsat TM and ETM+imagery.A total of 73,544 images were used to produce 29 annual image composites,generating∼400 TB of interim data products and resulting in∼25 TB of annual gap-free reflectance composites and change *** average,10%of pixels in the annual BAP composites were missing data,with 86%of pixels having data gaps in two consecutive years or *** detection overall accuracy was 89%.change attribution overall accuracy was 92%,with higher accuracy for standreplacing wildfire and *** were assigned to the correct year with an accuracy of 89%.Outcomes of this project provide baseline information and nationally consistent data source to quantify and characterize changes in forested *** methods applied and lessons learned build confidence in the products generated and empower others to develop or refine similar satellite-based monitoring projects.

关键词： Remote sensing big data forest change monitoring image processing

Environmental landscape determinants of maximum forest canopy height of boreal forests

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Journal of Plant Ecology 2019年第1期12卷 96-102页

作者： Lingfeng Mao christopher W.Bater John JStadt Barry White Piotr Tompalski nicholas c.coops Scott E.Nielsen Department of Renewable Resources University of AlbertaEdmontonAlberta T6G 2H1Canada Forest Management Branch Forestry DivisionAlberta Agriculture and ForestryEdmontonAlberta T5K 2M4Canada Department of Forest Resource Management University of British ColumbiaVancouverBritish Columbia V6T 1Z4Canada

Aims canopy height is a key driver of forest biodiversity and carbon *** estimates of canopy height are needed for assess-ing mechanisms relating to ecological patterns and processes of tree height *** global scales forest canopy height patterns are largely controlled by climate,while local variation at fine scales is due to differences in disturbance history and local patterns in envir-onmental *** relative effect of local environmental driv-ers on canopy height is poorly understood partly due to gaps in data on canopy height and methods for examining limiting ***,we used airborne laser scanning(ALS)data on vegetation structure of boreal forests to examine the effects of environmental factors on potential maximum forest canopy *** Relationships between maximum canopy height from ALS meas-ures and environmental variables were examined to assess factors limiting tree ***,we used quantile regression at the 0.90 quantile to relate maximum canopy height with environmental characteristics of climate(*** annual temperature[MAT]and mean annual precipitation),terrain(***)and depth-to-water(DTW)across a 33000 km2 multiple use boreal forest landscape in northeast Alberta,*** Findings Maximum canopy height was positively associated with MAT,ter-rain slope and terrain-derived DTW,collectively explaining 33.2%of the variation in *** strongest explanatory variable was DTW explaining 26%of canopy height variation with peatland forests having naturally shorter maximum canopy heights,but also more sites currently at their maximum potential *** con-trast,the most productive forests(*** to xeric upland forests)had the fewest sites at their potential maximum height,illustrating the effects of long-term forest management,wildfires and general anthropogenic footprints on reducing the extent and abundance of older,taller forest habitat in Alberta’s boreal forest.

关键词： forest succession vegetation structure quantile regression remote sensing airborne laser scanning(ALS)

Analytical model for predicting folding stable state of bistable deployable composite boom

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chinese Journal of Aeronautics 2024年第8期37卷 460-469页

作者： Tianwei LIU Jiangbo BAI nicholas FANTUZZI School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Jingdezhen Research Institute of Beihang University Jingdezhen 333000China DIcAM Department University of BolognaBologna 40136Italy

Bistable Deployable composite Boom(Bi-DcB)can achieve bistable function by storing and releasing strain energy,which has a good application prospect in space *** example,it serves as the main support section of deployable structures(e.g.,solar arrays and antennas).This paper investigates folding stable state of Bi-DcB through the analytical *** on Archimedes’helix and energy principle,an analytical model for predicting folding stable state of Bi-DcB was *** failure index of Bi-DcB in folding stable state were analyzed using the Tsai-Hill criterion and the maximum stress ***,a 2400 mm long Bi-DcB was fabricated using autoclave *** prediction results of the proposed model were compared with experiments and results of two other analytical *** is shown that the proposed model shows good prediction ***,the effect of geometric parameters on folding stable state of Bi-DcB was further investigated with the aid of the proposed model.

关键词： Bistable Deployable composite boom Solar arrays Antennas Archimedes’helix Folding Failure analysis

Design and synthesis of synthetic promoters for consistency of gene expression across growth phases and scale in ***

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Synthetic and Systems Biotechnology 2024年第2期9卷 330-339页

作者： Kristin V.Presnell Omar Melhem Sarah M.coleman nicholas J.Morse Hal S.Alper McKetta Department of chemical Engineering The University of Texas at Austin200E Dean Keeton St.Stop C0400AustinTX78712USA Institute for cellular and Molecular Biology The University of Texas at Austin2500 Speedway AvenueAustinTX78712USA

Metabolic engineering and synthetic biology endeavors benefit from promoters that perform consistently(or robustly)with respect to cellular growth phase(exponential and stationary)and fermentation scale(microtiter plates,tubes,flasks,and bioreactors).However,nearly all endogenous promoters(especially in Saccharomyces cerevisiae)do not perform in this *** this work,a hybrid promoter engineering strategy is leveraged to create novel synthetic promoters with robustness across these *** a multi-dimensional RNA-seq dataset,promoters with specific phase dependencies were *** enriched with functional transcription factors were identified using MEME *** motif-containing fragments could impart activity dependence in the opposing ***,we obtain two new promoters with high and consistent expression across both phases by increasing the exponential phase activity of the starting stationary-phase scaffold by 38 and 23-fold ***,we show that these promoters function consistently across various laboratory growth scales over time in a microtiter plate and in ***,this work presents and validates a new strategy for engineering promoters in *** with high levels of expression that are robust to cellular growth phase and the scale of the culture.

关键词： endogenous synthetic stationary

HDPairFinder:A data processing platform for hydrogen/deuterium isotopic labeling-based nontargeted analysis of trace-level amino-containing chemicals in environmental water

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Journal of Environmental Sciences 2024年第2期136卷 583-593页

作者： Tingting Zhao Kristin carroll caley B.craven nicholas J.P.Wawryk Shipei Xing Jian Guo Xing-Fang Li Tao Huan Department of chemistry Faculty of ScienceUniversity of British ColumbiaVancouver Campus2036 Main MallVancouverBritish ColumbiaV6T 1Z1Canada Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyFaculty of Medicine and DentistryUniversity of AlbertaEdmontonAlberta T6G 2G3Canada

The combination of hydrogen/deuterium(H/D)formaldehyde-based isotopic methyl labeling with solid-phase extraction and high-performance liquid chromatography–high resolution mass spectrometry(HPLc-HRMS)is a powerful analytical solution for nontargeted analysis of trace-level amino-containing chemicals in water *** the huge amount of chemical information generated in HPLc-HRMS analysis,identifying all possible H/Dlabeled amino chemicals presents a significant challenge in data *** address this,we designed a streamlined data processing pipeline that can automatically extract H/D-labeled amino chemicals from the raw HPLc-HRMS data with high accuracy and ***,we developed a cross-correlation algorithm to correct the retention time shift resulting from deuterium isotopic effects,which enables reliable pairing of H-and D-labeled ***,we implemented several bioinformatic solutions to remove false chemical features generated by in-source fragmentation,salt adduction,and natural13c ***,we used a data mining strategy to construct the AMINES library that consists of over 38,000 structure-disjointed primary and secondary amines to facilitate putative compound ***,we integrated these modules into a freely available R program,*** rationale of each module was justified and its performance tested using experimental H/D-labeled chemical standards and authentic water *** further demonstrated the application of HDPairFinder to effectively extract N-containing contaminants,thus enabling the monitoring of changes of primary and secondary N-compounds in authentic water *** is a reliable bioinformatic tool for rapid processing of H/D isotopic methyl labeling-based nontargeted analysis of water samples,and will facilitate a better understanding of N-containing chemical compounds in water.

关键词： Isotope labeling Nontargeted analysis Reactive N-compounds HPLc-HRMS Source water