Ports are under increased pressure to reduce their negative climate and environmental impacts. Their roles and functions in transportation systems and the economy make them a key industry in ...promoting sustainability. In particular, small- and medium-sized ports (SMSPs) should serve as lighthouses or flagships of environmental and digital transformation, allowing access to remote locations and integrating peripheral regions. Their sustainability planning faces significant challenges in this context, such as limited resources, access to technical expertise, and stakeholder involvement. Sustainable planning strives for long-term viability, while balancing economic, social, and environmental goals. Ports can ensure that they are cost-effective, environmentally sustainable, and capable of satisfying local people’s and companies’ long-term demands by applying sustainable planning methods. This research aims to assist stakeholders in designing and implementing activities that will optimize the sustainability of SMSPs, promote the sustainable development of the neighboring communities, and encourage the sustainable use of coastal and marine resources.
Abstract
We describe an algorithm for application of the classic “drizzle” technique to produce 3D spectral cubes using data obtained from the slicer-type integral field unit (IFU) spectrometers on ...board the James Webb Space Telescope. This algorithm relies upon the computation of overlapping volume elements (composed of two spatial dimensions and one spectral dimension) between the 2D detector pixels and the 3D data cube voxels, and is greatly simplified by treating the spatial and spectral overlaps separately at the cost of just 0.03% in spectrophotometric fidelity. We provide a matrix-based formalism for the computation of spectral radiance, variance, and covariance from arbitrarily dithered data and comment on the performance of this algorithm for the Mid-Infrared Instrument’s Medium Resolution IFU Spectrometer. We derive a series of simplified scaling relations to account for covariance between cube spaxels in spectra extracted from such cubes, finding multiplicative factors ranging from 1.5–3 depending on the wavelength range and kind of data cubes produced. Finally, we discuss how undersampling produces periodic amplitude modulations in the extracted spectra in addition to those naturally produced by fringing within the instrument; reducing such undersampling artifacts below 1% requires a four-point dithering strategy and spectral extraction radii of 1.5 times the point-spread function FWHM or greater.
Context.
The Mid-Infrared Instrument (MIRI) onboard the
James Webb
Space Telescope (JWST) will provide imaging, coronagraphy, low-resolution spectroscopy, and medium-resolution spectroscopy at ...unprecedented sensitivity levels in the mid-infrared wavelength range. The Medium Resolution Spectrometer (MRS) of MIRI is an integral field spectrograph that provides diffraction-limited spectroscopy between 4.9 and 28.3 μm, within a field of view (FOV) varying from ∼13 to ∼56 arcsec square. The design for MIRI MRS conforms with the goals of the JWST mission to observe high redshift galaxies and to study cosmology as well as observations of galactic objects, and stellar and planetary systems.
Aims.
From ground testing, we calculate the physical parameters essential for general observers and calibrating the wavelength solution and resolving power of the MRS which is critical for maximizing the scientific performance of the instrument.
Methods.
We have used ground-based observations of discrete spectral features in combination with Fabry-Perot etalon spectra to characterize the wavelength solution and spectral resolving power of the MRS. We present the methodology used to derive the MRS spectral characterization, which includes the precise wavelength coverage of each MRS sub-band, computation of the resolving power as a function of wavelength, and measuring slice-dependent spectral distortions.
Results.
The ground calibration of the MRS shows that it will cover the wavelength ranges from 4.9 to 28.3 μm, divided in 12 overlapping spectral sub-bands. The resolving power is
R
≳ 3500 in channel 1,
R
≳ 3000 in channel 2,
R
≳ 2500 in channel 3, and
R
≳ 1500 in channel 4. The MRS spectral resolution optimizes the sensitivity for detection of spectral features with a velocity width of ∼100 km s
−1
which is characteristic of most astronomical phenomena JWST aims to study in the mid-infrared. Based on the ground test data, the wavelength calibration accuracy is estimated to be below one-tenth of a pixel (0.1 nm at 5 μm and 0.4 at 28 μm), with small systematic shifts due to the target position within a slice for unresolved sources that have a maximum amplitude of about 0.25 spectral resolution elements. The absolute wavelength calibration is presently uncertain at the level of 0.35 nm at 5 μm and 46 nm at 28 μm, and it will be refined using in-flight commissioning observations.
Conclusions.
Based on ground test data, the MRS complies with the spectral requirements for both the
R
and wavelength accuracy for which it was designed. We also present the commissioning strategies and targets that will be followed to update the spectral characterization of the MRS.
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•Infrastructure and waste management are the major problems in the creation of a sustainable port.•Women are more positively inclined towards the development of such a port.•The labour force (group ...18–64) considers a green port positive.•Environmental and economic variables are assessed lower as the respondents’ age increases.•Citizens with a lower educational level have lower-rated social variables in relation to environment and economy with educational level.
As global maritime trade continues to soar, there is a growing demand for a sustainable balance between economic, social, and environmental performance. Thus, transparent assessment, strengthening the governance and scientific cooperation, as well as developing comprehensive communication are required amongst all interested parties to create realistic plans to meet sustainable development goals. This case study research thoroughly analyzes a Mediterranean port to find challenges and possible solutions to creating a sustainable port. The goal is to provide a methodology for policymakers to develop their future strategies for optimizing sustainable multi-objective design indicators. In addition, it addresses relative purposes for the sustainability of maritime transportation, such as improving energy efficiency, improving the quality of marine waters, and employing green technologies. Initially, key performance indicators were used to solve the multi-objective optimization problem. Then, using Statistical Package for Social Sciences (SPSS) software, the correlation of different criteria about specific demographics was studied. A factor analysis was applied by reducing the variables while maintaining as much information as possible. The methodology provides both quantitative and qualitative tools for policymakers to develop their future strategies to optimize environmental (i.e., new technological tools for reducing/eliminating pollution, recycling), social (i.e., motivations for social participation), and economic (i.e., willingness to pay) sustainability. The results indicated that the responders attributed low scores to road quality, traffic, and waste management but assessed positive indicators such as renewable energy resources, air quality, noise, and dust. Besides, a strong relationship was revealed between gender, age, and educational level with sustainability issues such as social acceptance, environmental awareness, and economic contribution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Context
. The Medium-Resolution Spectrometer (MRS) provides one of the four operating modes of the Mid-Infrared Instrument (MIRI) on board the
James Webb
Space Telescope (JWST). The MRS is an ...integral field spectrometer, measuring the spatial and spectral distributions of light across the 5–28 µm wavelength range with a spectral resolving power between 3700 and 1300.
Aims
. We present the MRS’s optical, spectral, and spectro-photometric performance, as achieved in flight, and we report on the effects that limit the instrument’s ultimate sensitivity.
Methods
. The MRS flight performance has been quantified using observations of stars, planetary nebulae, and planets in our Solar System. The precision and accuracy of this calibration was checked against celestial calibrators with well-known flux levels and spectral features.
Results
. We find that the MRS geometric calibration has a distortion solution accuracy relative to the commanded position of 8 mas at 5 µm and 23 mas at 28 µm. The wavelength calibration is accurate to within 9 km s
−1
at 5 µm and 27 km s
−1
at 28 µm. The uncertainty in the absolute spectro-photometric calibration accuracy was estimated at 5.6 ± 0.7%. The MIRI calibration pipeline is able to suppress the amplitude of spectral fringes to below 1.5% for both extended and point sources across the entire wavelength range. The MRS point spread function (PSF) is 60% broader than the diffraction limit along its long axis at 5 µm and is 15% broader at 28 µm.
Conclusions
. The MRS flight performance is found to be better than prelaunch expectations. The MRS is one of the most subscribed observing modes of JWST and is yielding many high-profile publications. It is currently humanity’s most powerful instrument for measuring the mid-infrared spectra of celestial sources and is expected to continue as such for many years to come.
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Context.
As is common for infrared spectrometers, the constructive and destructive interference in different layers of the
James Webb
Space Telescope (JWST) Mid-Infrared Instrument (MIRI) detector ...arrays modulate the detected signal as a function of wavelength. The resulting “fringing” in the Medium-Resolution Spectrometer (MRS) spectra varies in amplitude between 10% and 30% of the spectral baseline. A common method for correcting for fringes relies on dividing the data by a fringe flat. In the case of MIRI MRS, the fringe flat is derived from measurements of an extended, spatially homogeneous source acquired during the thermal-vacuum ground verification of the instrument. While this approach reduces fringe amplitudes of extended sources below the percent level, at the detector level, point source fringe residuals vary in a systematic way across the point spread function. The effect could hamper the scientific interpretation of MRS observations of unresolved sources, semi-extended sources, and point sources in crowded fields.
Aims.
We find MIRI MRS point source fringes to be reproducible under similar observing conditions. We want to investigate whether a generic and accurate correction can be determined. Therefore, we want to identify the variables, if they exist, that would allow for a parametrization of the signal variations induced by point source fringe modulations.
Methods.
We determine the point source fringe properties by analyzing MRS detector plane images acquired on the ground. We extracted the fringe profile of multiple point source observations and studied the amplitude and phase of the fringes as a function of field position and pixel sampling of the point spread function of the optical chain.
Results.
A systematic variation in the amplitude and phase of the point source fringes is found over the wavelength range covered by the test sources (4.9 − 5.8
μ
m). The variation depends on the fraction of the point spread function seen by the detector pixel. We identify the non-uniform pixel illumination as the root cause of the reported systematic variation. This new finding allows us to reconcile the point source and extended source fringe patterns observed in test data during ground verification. We report an improvement after correction of 50% on the 1
σ
standard deviation of the spectral continuum. A 50% improvement is also reported in line sensitivity for a benchmark test with a spectral continuum of 100 mJy. The improvement in the shape of weak lines is illustrated using a T Tauri model spectrum. Consequently, we verify that fringes of extended sources and potentially semi-extended sources and crowded fields can be simulated by combining multiple point source fringe transmissions. Furthermore, we discuss the applicability of this novel fringe-correction method to the MRS data (and the data of other instruments).
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Context.
The Mid-Infrared Instrument (MIRI) on board the
James Webb
Space Telescope (JWST) uses three Si:As impurity band conduction (IBC) detector arrays. The output voltage level of each MIRI ...detector pixel is digitally recorded by sampling up the ramp. For uniform or low-contrast illumination, the pixel ramps become nonlinear in a predictable way, but in areas of high contrast, the nonlinearity curve becomes much more complex. The origin of the effect is poorly understood and currently not calibrated out of the data.
Aims.
We provide observational evidence of the brighter-fatter effect (BFE) in MIRI conventional and high-contrast coronagraphic imaging, low-resolution spectroscopy, and medium-resolution spectroscopy data, and we investigate the physical mechanism that gives rise to the effect on the MIRI detector pixel raw voltage integration ramps.
Methods.
We used public data from the JWST/MIRI commissioning and Cycle 1 phase. We also developed a numerical electrostatic model of the MIRI detectors using a modified version of the public
Poisson_CCD
code.
Results.
We find that the physical mechanism behind the BFE manifesting in MIRI data is fundamentally different to that of charge-coupled devices and photodiode arrays such as the Hawaii-XRG near-infrared detectors used by the NIRISS, NIRCam, and NIRSpec instruments on board JWST. Observationally, the BFE makes the JWST MIRI data yield 10–25% larger point sources and spectral line profiles as a function of the relative level of de-biasing of neighboring detector pixels. This broadening impacts the MIRI absolute flux calibration, time-series observations of faint companions, and point spread function modeling and subtraction. We also find that the intra-pixel 2D profile of the shrinking Si:As IBC detector depletion region directly impacts the accuracy of the pixel ramp nonlinearity calibration model.
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Context
. The Medium Resolution Spectrometer (MRS) is one of the four observing modes of JWST/MIRI. Using JWST in-flight data of unresolved (point) sources, we can derive the MRS absolute spectral ...response function (ASRF) starting from raw data. Spectral fringing, caused by coherent reflections inside the detector arrays, plays a critical role in the derivation and interpretation of the MRS ASRF. The fringe corrections implemented in the current pipeline are not optimal for non-extended sources, and a high density of molecular features particularly inhibits an accurate correction.
Aims
. In this paper, we present an alternative way to calibrate the MIRI/MRS data. Firstly, we derive a fringe correction that accounts for the dependence of the fringe properties on the MIRI/MRS pupil illumination and detector pixel sampling of the point spread function. Secondly, we derive the MRS ASRF using an absolute flux calibrator observed across the full 5–28 µm wavelength range of the MRS. Thirdly, we apply the new ASRF to the spectrum of a G dwarf and compare it with the output of the JWST/MIRI default data reduction pipeline. Finally, we examine the impact of the different fringe corrections on the detectability of molecular features in the G dwarf and K giant.
Methods
. The absolute flux calibrator HD 163466 (A-star) was used to derive tailored point source fringe flats at each of the default dither locations of the MRS. The fringe-corrected point source integrated spectrum of HD 163466 was used to derive the MRS ASRF using a theoretical model for the stellar continuum. A cross-correlation was run to quantify the uncertainty on the detection of CO, SiO, and OH in the K giant and CO in the G dwarf for different fringe corrections.
Results
. The point-source-tailored fringe correction and ASRF are found to perform at the same level as the current corrections, beating down the fringe contrast to the sub-percent level in the G dwarf in the longer wavelengths, whilst mitigating the alteration of real molecular features. The same tailored solutions can be applied to other MRS unresolved targets. Target acquisition is required to ensure the pointing is accurate enough to apply this method. A pointing repeatability issue in the MRS limits the effectiveness of the tailored fringe flats is at short wavelengths. Finally, resulting spectra require no scaling to make the sub-bands match, and a dichroic spectral leak at 12.2 µm is removed.
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