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Record W2974088068

INVESTIGATING THE OPTIMAL TEMPORAL RESOLUTION OF SATELLITE DATA TO DETECT CLIMATE-INDUCED GRASSLAND PHENOLOGY CHANGES

2019· dissertation· en· W2974088068 on OpenAlexaboutno aff
Tengfei Cui

Bibliographic record

VenueUniversity Library (University of Saskatchewan) · 2019
Typedissertation
Languageen
FieldEarth and Planetary Sciences
TopicGeology and Paleoclimatology Research
Canadian institutionsnot available
Fundersnot available
KeywordsPhenologyGrasslandSatelliteRemote sensingEnvironmental scienceClimate changeClimatologyTemporal resolutionGeographyEcologyGeologyEngineeringBiology
DOInot available

Abstract

fetched live from OpenAlex

Phenology is as an effective indicator of vegetation response to climate change and variability, and satellite remote sensing is a promising approach to monitoring large-scale phenology changes across grasslands and other terrestrial biomes. Most satellite data to detect land surface phenology are composited at coarse time intervals to minimize noise and cloud contamination. Trading detailed seasonal dynamics for higher data quality of satellite composite data may affect the accuracy of estimated phenology and its response to climate variability. However, not many studies have investigated this issue. The purpose of this research is to evaluate the effect of the temporal resolutions of satellite data on the estimated climate-induced changes in grassland phenology. The research was conducted in the Canadian prairie grasslands. Satellite vegetation indices (VIs) including AVHRR and MODIS VIs produced at a wide range of temporal resolutions were used to estimate the start of growing season (SOG), the end of greenness (EOG) and other phenological metrics and their response to climate variability. The near-surface PhenoCam phenology data were used to validate the satellite-based phenology due to the lack of in-situ grassland phenology measurement in the Canadian prairies. The results show that the prairie grassland SOG and EOG are sensitive to the variability of the preseason drought, precipitation and temperature. Also, the temporal resolutions of MODIS VIs were indicated to influence the quality of estimated phenological metrics and ability of MODIS VIs to depict the detailed grassland seasonal dynamics. Moreover, the results reveal the different response of prairie grassland SOG and EOG to climate variability measured by MODIS and PhenoCam and demonstrate the 10-day time interval is the optimal temporal resolution of MODIS EVI2 to predict the climate-induced changes in PhenoCam-based grassland phenology. This research addressed a critical gap in satellite-based phenology detection, investigating the uncertainties of land surface phenology and its response to climate variability related to the temporal resolution of input satellite data in the mixed prairie. This research also improves the understanding of the variability of biome functions in relation to climate variability.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.254
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.001
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0020.000
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.033
GPT teacher head0.217
Teacher spread0.184 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2019
Admission routes1
Has abstractyes

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