Spectral Comparison Research Articles

The effect of mass spectrometry tuning frequency and criteria on ion relative abundances of cathinones and cannabinoids

Gas chromatography mass spectrometry is the most common instrument used for compound identification in untargeted seized drug analysis. Compound identification using this technique relies on mass spectra where the relative abundances (RAs) of all m/z values are compared manually or searched against a library database. An often-unappreciated aspect to any mass spectral comparison or search is the inherent variation in RAs. To address this, decades ago the Environmental Protection Agency (EPA) established tune check compounds as a means to control variation across vendor platforms. The goal of this study was to evaluate whether the DFTPP criteria, as defined by the EPA, could be used to reduce the RA variation in mass spectra produced by novel psychoactive substances (NPSs). Instruments from two vendors were used to analyze 6 NPSs: 4 cannabinoids and 2 cathinones. Each NPS was analyzed 100 times per instrument; 10 replicates per tune repeated under 10 different tunes. Results showed that passing a DFTPP tune check was not correlated with reduced RA variation. Tuning algorithm differences between vendors impacted variation, but the frequency of instrument tuning was found to be the most critical factor for controlling RA variation. The results of this work suggest that forensic laboratories should develop quantitative metrics to evaluate autotuning results and define how these metrics will be used to dictate maintenance. This practice, coupled with tuning before each analytical batch, will reduce the variation of %RA values as much as practicable.

A Spectral Comparison of Jarosites Using Techniques Relevant to the Robotic Exploration of Biosignatures on Mars.

The acidic sulfate-rich waters of the Meridiani Planum region were potentially a habitable environment for iron-oxidizing bacteria on ancient Mars. If life existed in this ancient martian environment, jarosite minerals precipitating in these waters may record evidence of this biological activity. Since the Meridiani jarosite is thermodynamically stable at the martian surface, any biosignatures preserved in the jarosites may be readily available for analysis in the current surface sediments during the ongoing robotic exploration of Mars. However, thermal decomposition experiments indicate that organic compound detection of sediments containing jarosite may be challenging when using pyrolysis experiments; the instrument commonly used to assess organic matter in martian samples. So, here, we assess if the biogenicity of the Meridiani-type jarosites can be determined using complimentary spectroscopic techniques also utilized during the robotic exploration of Mars, including the upcoming ExoMars2020 rover mission. An abiotic jarosite, synthesized following established protocols, and a biological jarosite counterpart, derived from a microbial enrichment culture of Rio Tinto river sediments, were used to compare four spectroscopy techniques employed in the robotic exploration of Mars (Raman spectroscopy, mid-infrared (IR) spectroscopy, visible near-infrared reflectance (VNIR) spectroscopy and Mössbauer spectroscopy) to determine if the complimentary information obtained using these instruments can help elucidate the biological influence of Meridiani-type jarosites. Raman spectral differences might be due to the presence of unreacted reagents in the synthetic spectra and not biological contributions. Reflectance (IR/VNIR) spectra might exhibit minor organic absorption contributions, but are observed in both sample spectra, and do not represent a biosignature. Mössbauer spectra show minor differences in fit parameters that are related to crystal morphology and are unrelated to the biological (i.e., organic) component of the system. Results of this study suggest that the identification of biosignatures in Meridiani-type jarosites using the in situ robotic exploration on Mars may be possible but will be challenging. Our work provides additional insight into extraterrestrial biosignature detection and data interpretation for Mars exploration and indicates that sample return missions are likely required to unequivocally resolve the possible biogenicity of the Meridiani sediments or other jarosite-containing sediments.

Mineral identification in LWIR hyperspectral imagery applying sparse-based clustering

ABSTRACTAn assessment of mineral identification applying hyperspectral infrared imagery in laboratory conditions is presented here and strives to identify nine different minerals (biotite, diopside, epidote, goethite, kyanite, scheelite, smithsonite, tourmaline, quartz). A hyperspectral camera in Long-Wave Infrared (LWIR, 7.7–11.8 m) with a LW-macro lens, an infragold plate, and a heating source are instruments used in the experiment. For automated identification, a Sparse Principal Component Analysis (Sparse PCA)-based K-means clustering is employed to categorise all pixel-spectra in different groups. Then the best representatives of each cluster (using spectral averaging) are chosen to compare these spectra to ASTER spectral library of JPL/NASA through spectral comparison techniques. Spectral angle mapper (SAM) and Normalized Cross Correlation (NCC) are two of such techniques, which are used herein to measure the spectral difference. In order to evaluate robustness of clustering results among the minerals spectra, we have added three levels of Gaussian and salt&pepper noise, , and , to input spectra which dropped the accuracy percentage from more than 84.73, for 0 added noise, to 44.57, for 2 average of both additive noise, and 22.21, for 4 additive noise. The results conclusively indicate a promising performance but noise sensitive behaviour of the proposed approach.

Comparison of tri-, tetra- and pentacyclic caged hydrocarbons in Australian crude oils and condensates

Thermally stable and biodegradation resistant, the tricyclic and pentacyclic diamondoid caged hydrocarbons are commonly used as source and maturity indicators of oils and potential source-rocks, but similar tetracyclic structures appear to have received much less attention. Using two-dimensional (2D) gas chromatography – time of flight mass spectrometry (GC × GC-TOFMS), 29 Australian crude oils and condensates were analysed for the presence of caged C12H18 tetracyclics such as ethanoadamantane and iceane. The thermodynamically more stable 2,4-ethanoadamantane was identified by comparison with a synthesised authentic standard. Three of its bridgehead methyl-substituted isomers, 6-methylethanoadamantane (6-ME), 1-ME and 2-ME, were tentatively assigned based on mass spectral comparison and relative elution order. Further series of non-bridgehead methyl isomers, plus dimethyl isomers, were also inferred based on mass spectra and 2D elution positions. The tri-, tetra and pentacyclic caged hydrocarbons and their methyl-substituted homologues were semi-quantified in the Australian oils. The potential of a novel index, the methylethanoadamantane index (MEI), based on the ratio of the more stable bridgehead isomers divided by the sum of all the methyl substituted isomers (MEI = Σ(6-ME + 1-ME + 2-ME)/ΣTotal methylethanoadamantanes), was explored. A significant positive association was found between the MEI and MAI (r2 = 0.203, p < 0.05) and a significant negative association was found between MEI and MDI (r2 = 0.246, p < 0.05). Stronger relationships were found for other commonly applied diamondoid ratio indices, including Σ Methyl Adamantanes/Σ Methyl Diamantanes (ΣMA/ΣMD) versus ΣMA/ΣME (r2 = 0.781, p < 0.0001, n = 26). The relatively low volatility of the ethanoadamantanes compared to the adamantanes and their likely greater resistance to microbial attack than the ethyladamantanes, may make analysis of these compounds a useful addition to the commonly measured diamondoids.

Withanolides and 26-Hydroxylated Derivatives with Anti-Inflammatory Property from Solanum Capsicoide

Abstract A phytochemical investigation of the leaves of Solanum capsicoides resulted in the isolation and characterization of five new withanolide-type steroids, capsisteroids G–K (1–5), along with three known analogues (6–8). Their structures were identified by interpretation of the NMR and HRESIMS data as well as by spectral data comparison with known analogues. The isolated steroids were found to be not cytotoxic against a limited panel of cancer cell lines. The ability of the isolated steroids to suppress superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophils was also evaluated and displayed variable activities.

Spectral comparison of diffuse PAR irradiance under different tree and shrub shading conditions and in cloudy days

Spectral Solar Photosynthetically Photon Flux Density (PPFD) (380 to 780 nm) reaching the surface of a plant in different lighting conditions has been analyzed in order to better understand the different photosynthetic performance of plants depending on their spatial situation and the vegetation surrounding.A comparison between the shadow of several trees in a sunny day and the case of a cloudy day in an open space has been studied. Three isolated trees (a palm tree, an olive tree and a shrub oleander) and a tipuana grove have been studied.The study has been developed in Valencia (Spain) during January and February 2017. A portable Asensetek Standard ALP-01 spectrometer with a measurement wavelength range of 380 to 780 nm, has been used. Conditions with higher PPFD received are found to be, apart from those of a sunny day, those for cloudy day (with a spectral maximum in the Green region of the spectrum), and those for individual trees and shrub shadows in a sunny day (with a spectral maximum in the Blue region). The case in which less amount of PPFD is received is that under the shadow of tipuana grove (with a spectral maximum in the Infrared region of the spectrum). In fact the order of magnitude in which the PPFD in a cloudy day exceeds the PPFD under the tipuana grove shade is up to 20.

Terahertz spectroscopic imaging with discriminant analysis for detecting foreign materials among sausages

The accurate and rapid detection of foreign materials in food products is essential for ensuring food safety and quality. Terahertz (THz) imaging is an emerging technology for non-destructive detection in food industrial with the advantages of non-ionization and spectroscopic fingerprinting. In this study, we have attempted to explore the effectiveness of THz spectroscopic imaging for foreign material detection in food with complicated compositions. The feasibility of locating contaminations in sausages were demonstrated through typical spectral comparison, spectral classification assisted by principal component analysis and discriminant analysis methods, and one-dimensional scanning spectral analysis. Our imaging results indicated THz spectroscopic imaging has the ability to locate metal contaminations in sausages no matter what part of sausages is as the food matrix. This study will provide new knowledge about foreign material detection in food with complicated compositions and a basis for parameters selection of continuous-wave THz imaging for contamination detection in this case.

Bifurcation analysis of coexistent state in a delayed two-species predator-prey model

ABSTRACTIn this paper, we consider a delayed two-species predator-prey model with general functional response under the homogeneous Neumann boundary condition. We discuss the stability of the trivial and semi-trivial solutions and obtain the spatially nonhomogeneous bifurcation solutions stemming from the semi-trivial trivial solutions and . Besides, the stability and some results of Hopf bifurcation at the spatially nonhomogeneous bifurcation steady-state solutions are investigated by analyzing the distribution of the eigenvalues. The method we applied here is mainly based on spectral analysis, comparison principle, Lyapunov-Schmidt reduction, and bifurcation theory.

Comparison of variable selection methods prior to linear discriminant analysis classification of synthetic phenethylamines and tryptamines

Identification of emerging synthetic designer drugs is challenging in the absence of reference materials for subsequent mass spectral comparison. In this work, linear discriminant analysis (LDA) models were developed and validated for the characterization of compounds according to structural class based on mass spectral features. A set of synthetic phenethylamines and tryptamines was analyzed by gas chromatography-mass spectrometry (GC–MS) and the resulting spectra were probed to identify characteristic variables (m/z values) for model development. Two approaches were used to select characteristic variables. First, ions known to be characteristic of each compound class were selected, resulting in a total of 13 variables that were used to develop an LDA model. Following cross validation of the model, a test set of phenethylamines and tryptamines was classified, resulting in a successful classification rate of 93%. In the second approach, principal components analysis (PCA) was used as a more objective method for variable selection. With this approach, a total of 9 variables were selected and the resulting LDA model generated a successful classification rate of 86%.While the classification success of each LDA model was similar, the PCA method for variable selection is substantially less time consuming than the more detailed approach that requires probing mass spectra for characteristic features. Classification models such as those reported here have potential utility for the class characterization of emerging analogs for which reference materials are not yet available.

Remote sensing evidence for a possible 10 kilometer in diameter impact structure in north-central Niger

Remote sensing investigations of West Africa reveal a roughly 10 km in diameter, circular feature in north-central Niger. The circular feature is located within Early Devonian fluvio-marine sedimentary strata about 100 km to the north of a suite of igneous ring dikes located in the Aïr Massif. Whether the circular feature is related to the ring dikes, structural doming, or an impact crater can be evaluated from earlier geologic mapping (Black, 1967) and image analyses. Previous mapping indicates that the circular feature is defined by outcrops of Devonian Idekel sandstone and the Late Proterozoic, weakly-metamorphosed molasse of the Proche-Ténéré Formation. Absent in published lithologic descriptions of these sedimentary and metasedimentary rocks are diapiric evaporite deposits that could produce the observed circular morphologies. Lithologies that define the circular feature are confirmed by classification techniques using the ENVI software platform and band ratios/math from Landsat 8 and Sentinel 2A data. Spectral profile comparisons between the igneous intrusive rocks exposed in the Aïr Massif, outcrops of sedimentary rock that are proximal to the circular feature, and desert sand confirm that the sedimentary rocks mapped by Black (1967) define the circular feature. The shallow subsurface structure, revealed through Spaceborne Imaging Radar-C data, and 3-D modeling using Sentinel 1A data, is also not consistent with nearby ring dike structures. These data suggest that the circular feature did not likely form as a magmatic intrusion close to the time of sedimentary rock deposition. We propose that the circular feature formed from either a meteorite impact after deposition of the host sedimentary units or by some other, but less likely, geologic process. Confirmation of an impact explanation for the circular feature would require sample analysis and inspection for shock-metamorphosed materials.

A Prediction-Based Spatial-Spectral Adaptive Hyperspectral Compressive Sensing Algorithm.

In order to improve the performance of storage and transmission of massive hyperspectral data, a prediction-based spatial-spectral adaptive hyperspectral compressive sensing (PSSAHCS) algorithm is proposed. Firstly, the spatial block size of hyperspectral images is adaptively obtained according to the spatial self-correlation coefficient. Secondly, a k-means clustering algorithm is used to group the hyperspectral images. Thirdly, we use a local means and local standard deviations (LMLSD) algorithm to find the optimal image in the group as the key band, and the non-key bands in the group can be smoothed by linear prediction. Fourthly, the random Gaussian measurement matrix is used as the sampling matrix, and the discrete cosine transform (DCT) matrix serves as the sparse basis. Finally, the stagewise orthogonal matching pursuit (StOMP) is used to reconstruct the hyperspectral images. The experimental results show that the proposed PSSAHCS algorithm can achieve better evaluation results—the subjective evaluation, the peak signal-to-noise ratio, and the spatial autocorrelation coefficient in the spatial domain, and spectral curve comparison and correlation between spectra-reconstructed performance in the spectral domain—than those of single spectral compression sensing (SSCS), block hyperspectral compressive sensing (BHCS), and adaptive grouping distributed compressive sensing (AGDCS). PSSAHCS can not only compress and reconstruct hyperspectral images effectively, but also has strong denoise performance.

Power alternator simulation models for diagnostic purposes

Park models, also known as dq-models, are a simple and very efficient way to obtain a faithful image of the behaviour of a machine in transient and steady-state operating conditions to deal with control issues. Their precision is based on the use of saturated direct and quadrature reactances that truly represent the dynamics and the magnitude of the electrical signals at nominal operating point. However, these constant parameters are not sufficient to accurately take into account the saliency of the machine and, therefore, to precisely simulate the harmonic contents of these signals: the latter point can be very problematic for diagnostic purposes. This paper uses simulation results and experimental measurements on a Leroy-Somer 27kVA alternator to clearly show the lack of coherence between the simulated spectra from a dq-model and the experimental data retrieved from a real power alternator. For that reason, a new methodology of machine modelling consisting of a co-simulation process between Flux2D and Matlab software is presented. The use of finite elements enables a fine identification of the inductances of the system. These take into account the geometrical specificities of both the exciter and the main generator and are then used in an analytical model developed in the Matlab environment. Spectral comparisons with experimental data demonstrate the improved accuracy of this new modelling method compared to dq-models in terms of harmonic contents.

Pulse‐like versus non‐pulse‐like ground motion records: Spectral shape comparisons and record selection strategies

SummaryPulse‐like records are well recognized for their potential to impose higher demands on structures when compared with ordinary records. The increased severity of the structural response usually caused by pulse‐like records is commonly attributed to the spectral increment around the pulse period. By comparing the building response to sets of spectrally equivalent pulse‐like and ordinary records, we show that there are characteristics of pulse‐like records beyond the shape of the acceleration response spectrum that affect the results of nonlinear dynamic analysis. Nevertheless, spectral shape together with the ratio of pulse period to the first‐mode structural period, Tp/T1, are confirmed as “sufficient” predictors for deformation and acceleration response metrics in a building, conditioned on the seismic intensity. Furthermore, the average spectral acceleration over a period range, AvgSA, is shown to incorporate to a good proxy for spectral shape, and together with Tp/T1, form an efficient and sufficient intensity measure for response prediction to pulse‐like ground motions. Following this latter route, we propose a record selection scheme that maintains the consistency of Tp with the hazard of the site but uses AvgSA to account for the response sensitivity to spectral shape.

CCN Spectral Shape and Stratus Cloud and Drizzle Microphysics

AbstractThe shapes of high‐resolution cloud condensation nucleus (CCN) spectra are compared with cloud and precipitation characteristics observed in the Marine Stratus/Stratocumulus Experiment. These high‐resolution spectra often revealed bimodality that is usually caused by in‐cloud processing. Bimodal CCN spectra were associated with clouds that had as much as double the concentrations of droplets with narrower distributions and as much as an order of magnitude less drizzle than clouds associated with the most extreme unimodal CCN spectra. We introduce objective CCN spectral metrics: (1) CCN concentration differences between the two modes, unprocessed (Aitken, Nu) and processed (accumulation, Np), and (2) slopes of cumulative CCN spectra. Both of these CCN spectral shape classifications show similar cloud droplet concentration (Nc) trends to that of an earlier subjective modal rating system. When there are two modes, they are separated either by minimal concentrations or concentration inflections. Enhancement of Nc is traced to greater CCN bimodality that causes narrower droplet spectra that suppress drizzle. These effects could augment indirect aerosol effects and can only be revealed by high‐resolution CCN spectral shape comparisons with cloud and drizzle microphysics.

Spectral, spatial, and temporal characteristics of underwater ambient noise in the Beaufort Sea in 1994 and 2016

Climate induced changes in the Arctic Ocean have severely impacted underwater acoustic communication and navigation; understanding underwater noise characteristics is critical to improving the performance of these operations. Ambient noise from the Beaufort Sea recorded in experiments more than 20 years apart (SIMI94 and ICEX16) are compared to determine differences that may be attributed to the region's rapidly changing environment. Both datasets are collected at spring time under packed ice conditions with 32 element vertical line arrays. Spectral comparison shows noise within 20–300 Hz band is 30–40 dB louder in 1994 than 2016, suggesting the ice cover during SIMI94 was more acoustically active. Beamforming results show ambient noise vertical directionality is focused near the horizontal during SIMI94 but more spread in elevation during ICEX16, with a robust noise notch at the horizontal. Numerical modeling demonstrates that this difference may be attributed to ambient noise during ICEX16 being dominated by surface noise sources at discrete ranges rather than the historical assumption of a continuous and uniform distribution of sources. Temporal statistics of transient ice events show more transient activity during SIMI94 and appear to support the new proposed surface source distribution for ICEX16. [Work supported by ONR and DARPA STO.]

A spectral synergy method to retrieve martian water vapor column-abundance and vertical distribution applied to Mars Express SPICAM and PFS nadir measurements

Up to now, all attempts to retrieve martian water vapor from nadir observations have focused their analysis on a single spectral domain and comparison between the results of various experiments showed the difficulty to reconcile the water vapor datasets together. Inspired by a methodology recently developed for the analysis of Earth observations, a spectral synergy approach has been tested on the water vapor extraction from the measurements of two instruments onboard Mars Express. These instruments cover near-infrared (NIR) and thermal infrared (TIR) domains within which water vapor possesses diagnostic absorption/emission signatures. Since the two instruments have operated concomitantly around Mars, co-located measurements could be selected and processed to create a dataset exploitable by synergy. The synergy relies on a Bayesian inference algorithm to find the best fitting values of water vapor and other parameters (e.g. atmospheric and surface temperature, dust opacity) simultaneously for both NIR and TIR intervals. Results demonstrate that synergy augments the information content about water vapor by up to >50% compared to traditional non-synergistic methods. Not only does the synergy provide an unbiased estimate of the total column abundance of H2O but it also provides a correspondingly unbiased estimate of H2O abundance in the first 5 km of the boundary layer, an atmospheric region long remained unexplored although being known for hosting key mechanisms controlling the fate of volatiles on Mars. Using synergy, the scientific return of nadir observations of current and future missions at Mars (such as the ExoMars Trace Gas Orbiter) can be fully optimized.

The first high-resolution observations of 37.7-, 38.3- and 38.5-GHz methanol masers

We have used the Australia Telescope Compact Array (ATCA) to undertake the first high angular resolution observations of 37.7-GHz ($7_{-2} - 8_{-1}E$) methanol masers towards a sample of eleven high-mass star formation regions which host strong 6.7-GHz methanol masers. The 37.7-GHz methanol sites are coincident to within the astrometric uncertainty (0.4 arcseconds) with the 6.7-GHz methanol masers associated with the same star formation region. However, spatial and spectral comparison of the 6.7- and 37.7-GHz maser emission within individual sources shows that the 37.7-GHz masers are less often, or to a lesser degree co-spatial than are the 12.2-GHz and 6.7-GHz masers. We also made sensitive, high angular resolution observations of the 38.3- and 38.5-GHz class II methanol transitions ($6_{2} - 5_{3}A^{-}$ and $6_{2} - 5_{3}A^{+}$, respectively) and the 36.2-GHz ($4_{-1} - 3_{0}E$) class I methanol transition towards the same sample of eleven sources. The 37.7-, 38.3- and 38.5-GHz methanol masers are unresolved in the current observations, which implies a lower limit on the brightness temperature of the strongest masers of more than $10^6$K. We detected the 38.3-GHz methanol transition towards 7 sources, 5 of which are new detections and detected the 38.5-GHz transition towards 6 sources, 4 of which are new detections. We detected 36.2-GHz class I methanol masers towards all eleven sources, 6 of these are new detections for this transition, of which 4 sources do not have previously reported class I methanol masers from any transition.

The Largest Electron Differential Energy Flux Observed at Mars by the Mars Express Spacecraft, 2004-2016.

The goal of this paper is to understand the processes by which solar wind electrons are energized in the Martian magnetosphere and how this compares to processes at Venus and Earth. Each is unique in the source of its magnetic field topology and how this influences electron energization. To achieve this goal, 24 million spectra spanning 13 years have been examined using the electron spectrometer from the Mars Express spacecraft between about 12,000 km and about 250 km altitude, and from all latitudes and local times. The top 10 largest differential energy flux at energies above the differential energy flux peak have been found: seven spectra from the magnetosheath near noon, three from the dark tail (the largest two from the middle and ionospheric edge of the magnetosheath). Spectral comparisons show a decade range in the peak of the electron distributions; however, all distributions show a similar energy maximum dictated by solar wind/planet interaction. Similarly derived, the largest Venus spectrum occurred near the magnetosheath bow shock and had the same shape as the most intense Mars inner magnetosheath spectrum. The Mars and Venus dayside spectra compared to the Mars nightside spectrum that included an enhanced optical signal attributed to discrete “auroral” precipitation show a similar shape. These spectra are also compared to a selected auroral zone electron spectra from the Earth. The Mars and Venus results suggest that there is no more energy needed to generate electrons forming the nightside precipitation than is gained during the solar wind/planet interaction.

Comparison results for splitting iterations for solving multi-linear systems

It is known that the spectral radius of the iterative tensor can be seen as an approximate convergence rate for solving multi-linear systems by tensor splitting iterative methods. So in this paper, first we give some spectral radius comparisons between two different iterative tensors. Then, we propose the preconditioned tensor splitting method for solving multi-linear systems, which provides an alternative algorithm with the choice of a preconditioner. In particular, also we give some spectral radius comparisons between the preconditioned iterative tensor and the original one. Numerical examples are given to demonstrate the efficiency of the proposed preconditioned methods.

Evaluation of phenospectral dynamics with Sentinel-2A using a bottom-up approach in a northern ombrotrophic peatland

Peatlands cover very large extents in northern regions and play a significant role in the global carbon cycle by functioning as a carbon sink. Large-scale satellite based monitoring systems, such as the Sentinel-2 Multispectral Instrument (MSI), are necessary to improve our understanding of how these ecosystems respond to climate change by providing verifiable land products. For instance, satellite-based land product validation approaches can benefit from airborne hyperspectral imagery and in-situ data, which provide higher spatial and spectral resolution baselines, ideal for measuring vegetation changes (e.g. phenology, LAI) at local scales. Here, we assessed the short-term phenospectral dynamics (spectral changes indicated by specific spectral features as a function of phenology) of five ombrotrophic peatland vegetation physiognomies over four dates at the Mer Bleue bog in Canada. We took advantage of a unique remote sensing data acquisition campaign aiming to validate Sentinel-2A land products, and analyzed three spatially and spectrally distinctive datasets (i.e. field spectra, VISNIR airborne hyperspectral imagery (HSI) and Sentinel-2A imagery) over the first half of the 2016 growing season. By implementing a bottom-up approach, first we assessed the airborne HSI's capability to detect phenological changes as compared to in-situ acquired field spectroscopy measurements in a 10 ha area at Mer Bleue and evaluated the spectral features characteristic of these phenological changes. Second, over the entire Mer Bleue area (28,000 ha), we compared a series of four Sentinel-2A images to four airborne HSI mosaics (spatially and spectrally resampled to Sentinel-2A) to assess the utility of Sentinel-2A for detecting small spectral variations due to phenological changes (i.e. greening). In addition, for this second comparison, three spectral vegetation indices were derived from the Sentinel-2A images and the airborne HSI mosaics. The spectral comparisons between the airborne HSI and the field spectroscopy data revealed clear phenological changes from the airborne HSI. For instance, a closer agreement between reflectance measured by the field spectrometer and the airborne HSI spectral response was found in the visible region (450–680 nm). A greater difference however, was consistently seen in the near-infrared region (681–866 nm) across the four dates. Narrow spectral features in three regions of the visible range (global minima, red absorption, green peak), indicating changes in vegetation colour, were consistent for both datasets and with expected phenological patterns at Mer Bleue. At the landscape level, Sentinel-2A mirrored the spectral changes depicted by the resampled HSI data. However, band level, pair-wise comparisons showed significant differences (p < 0.001) in reflectance for each band, with Sentinel-2A exhibiting higher reflectance values than the HSI for the first three dates. Only for the last date (June 23rd) did the airborne HSI have higher reflectance values or no significant difference with the Sentinel-2A data. Overall, our three datasets captured the short-term phenological changes at Mer Bleue and have provided promising results in terms of using the Sentinel-2A MSI sensor to monitor these changes at the landscape level.