نتایج جستجو برای: models of phenology

تعداد نتایج: 21225267  

Journal: :Remote Sensing 2015
Martin Karlson Madelene Ostwald Heather Reese Josias Sanou Boalidioa Tankoano Eskil Mattsson

Accurate and timely maps of tree cover attributes are important tools for environmental research and natural resource management. We evaluate the utility of Landsat 8 for mapping tree canopy cover (TCC) and aboveground biomass (AGB) in a woodland landscape in Burkina Faso. Field data and WorldView-2 imagery were used to assemble the reference dataset. Spectral, texture, and phenology predictor ...

2007
Jeremy I. Fisher John F. Mustard

Phenological records constructed from global mapping satellite platforms (e.g. AVHRR and MODIS) hold the potential to be valuable tools for monitoring vegetation response to global climate change. However, most satellite phenology products are not validated, and field checking coarse scale (≥500 m) data with confidence is a difficult endeavor. In this research, we compare phenology from Landsat...

Journal: :Global change biology 2016
Kevin R Ford Constance A Harrington Sheel Bansal Peter J Gould J Bradley St Clair

Under climate change, the reduction of frost risk, onset of warm temperatures and depletion of soil moisture are all likely to occur earlier in the year in many temperate regions. The resilience of tree species will depend on their ability to track these changes in climate with shifts in phenology that lead to earlier growth initiation in the spring. Exposure to warm temperatures ('forcing') ty...

Journal: :Ecology letters 2010
Louie H Yang V H W Rudolf

Climate change is altering the phenology of many species and the timing of their interactions with other species, but the impacts of these phenological shifts on species interactions remain unclear. Classical approaches to the study of phenology have typically documented changes in the timing of single life-history events, while phenological shifts affect many interactions over entire life hist...

Journal: :journal of crop protection 2015
guillermo heit walter sione pablo cortese

lobesia botrana (denis & schiffermüller) (lepidoptera: tortricidae), is an important vineyard-pest in the european and mediterranean areas and it was recently described in argentina and chile. since knowledge on the l. botrana phenology on argentina is still limited, the objective of this study was to develop a phenological model to predict voltinism of l. botrana in argentina through a reg...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه - پژوهشکده ادبیات 1393

testing plays a vital role in any language teaching program. it allows teachers and stakeholders, including program administrators, parents, admissions officers and prospective employers to be assured that the learners are progressing according to an accepted standard (douglas, 2010). the problems currently facing language testers have both practical and theoretical implications but the first i...

Journal: :Remote Sensing 2016
Erica L. Garroutte Andrew J. Hansen Rick L. Lawrence

The Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) have gained considerable attention in ecological research and management as proxies for landscape-scale vegetation quantity and quality. In the Greater Yellowstone Ecosystem (GYE), these indices are especially important for mapping spatiotemporal variation in the forage available to migratory elk (Cervus e...

2015
James R Bell Lynda Alderson Daniela Izera Tracey Kruger Sue Parker Jon Pickup Chris R Shortall Mark S Taylor Paul Verrier Richard Harrington

Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. Our ma...

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