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2022 IEEE International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea), 3-5 October 2022, Milazzo, Italy.-- © 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.-- 5 pages, 6 figures, In this study, wind speed is estimated from COSMO-SkyMed (CSK) Synthetic Aperture Radar (SAR) imagery using two approaches, which both exploit the X-band Geophysical Model Function (GMF) XMOD2 developed for the German TerraSAR-X SAR mission. The first approach uses external wind direction information provided by collocated ASCAT scatterometer measurements; the second one incorporates wind direction derived from the SAR scene using the Continuous Wavelet Transform (CWT). Experimental results, obtained using a relatively small collocated CSK data set, show the robustness of the wind estimation from the CSK imagery that result in accurate enough estimates under a range of incidence angles that span between 30° and 50°. The CWT approach allows reliable wind estimates on a 1km spatial grid, We thank to the Italian Space Agency (ASI) for funding the APPLICAVEMARS project (ASI contract n. 2021-4-U.0) within the framework of the call DC-UOT-2019-017

In this study, a new antenna pattern deconvolution method to enhance the spatial resolution of multi -channel microwave radiometer (MWR) measurements is developed. This technique, based on a conventional gradient-like iterative method, utilizes the information contained in a high-frequency channel to enhance the spatial resolution of the lower-frequency channel in a data-fusion fashion. The physical idea consists of initializing the gradient -like inversion scheme using higher frequency details that are filtered out by the system measurement function. Experiments, performed on a dataset that includes both simulated and actual radiometer measurements, show that the proposed technique allows outperforming the conventional gradient method, while being very robust with respect to artifacts that could be induced by the higher frequency channel.

In this paper, we introduce a novel approach to enhance the spatial resolution of single-pass microwave data collected by mesoscale sensors. The proposed rationale is based on an $L^{p}$ -minimization approach with a variable $p$ exponent. The algorithm automatically adapts the $p$ exponent to the region of the image to be reconstructed. This approach allows taking benefit of the advantages of both the regularization in Hilbert ( $p = 2$ ) and Banach ( $1 ) spaces. Experiments are undertaken considering the microwave radiometer and refer to both actual and simulated data collected by the special sensor microwave imager (SSM/I). Results demonstrate the benefits of the proposed method in reconstructing abrupt discontinuities and smooth gradients with respect to conventional approaches in Hilbert or Banach spaces.

An enhanced spatial resolution brightness temperature product is proposed for future conical scan microwave radiometers. The technique is developed for Copernicus Imaging Microwave Radiometer (CIMR) measurements that are simulated using the CIMR antenna pattern at the L-band and the measurement geometry proposed in the Phase A study led by Airbus. An inverse antenna pattern reconstruction method is proposed. Reconstructions are obtained using two CIMR configurations, namely, using measurements collected at L-band by the forward (FWD) scans only, and combining forward and backward (FWD+BWD) scans. Two spatial grids are adopted, namely, 3km × 3 km and 36km × 36km. Simulation results, referred to synthetic and realistic reference brightness fields, demonstrate the soundness of the proposed scheme that provides brightness temperature fields reconstructed at a spatial resolution up to ~1.9 times finer than the measured field when using the FWD+BWD combination., This work has been produced for the European Space Agency (ESA) in the frame of the Copernicus programme as a partnership between ESA and the European Commission.

In this study, a method to improve the reconstruction performance of antenna-pattern deconvolution based on the gradient iterative regularization scheme is proposed. The method exploits microwave measurements acquired by a multichannel radiometer to enhance their native spatial resolution. The proposed rationale consists of using the information carried on a high-frequency (finer spatial resolution) channel to ameliorate the spatial resolution of the lowest resolution radiometer channel. Experiments performed using both synthetic and real special sensor microwave/imager (SSM/I) radiometer data demonstrate that an enhanced spatial resolution 19.35-GHz channel can be obtained by ingesting in the algorithm information coming from 37.0-GHz channel. This multichannel spatial resolution method is also shown to outperform the conventional gradient-like regularization scheme in terms of both observation of smaller targets and reduction of ringings and fluctuations.

This study addresses the spatial resolution enhancement of synthetic microwave radiometer observations obtained by the Soil Moisture Active Passive (SMAP) L-Band Radiometer. An antenna pattern deconvolution method is used together with an iterative regularization scheme to reconstruct the brightness field at enhanced spatial resolution. Results obtained processing both synthetic and actual SMAP measurements show that sharper edges and coastlines can be reconstructed in a very effective way.

In this letter, a new approach is proposed to ameliorate the performance of iterative gradient-like regularization schemes aimed at enhancing the spatial resolution of microwave radiometer measurements in the Hilbert space. The approach consists of preconditioning the ill-conditioned discrete problem to let the iterative gradient-based inversion technique be more computer-time effective. Experiments undertaken on the simulated radiometer brightness profiles demonstrate the soundness of the proposed rationale that outperforms conventional gradient-like methods in terms of both computer-time effectiveness and accuracy in reconstructing spot-like discontinuities while resulting in larger fluctuations over the background.

This study addresses the spatial resolution enhancement of synthetic microwave radiometer observations as obtained by the forthcoming Copernicus Imaging Microwave Radiometer (CIMR). An antenna pattern deconvolution scheme is used to exploit the actual L-band CIMR antenna pattern together with a regularization scheme to reconstruct the brightness field at enhanced spatial resolution. Simulation results, referred to synthetic and realistic reference brightness fields, demonstrate the soundness of the proposed scheme that provides brightness fields reconstructed at a spatial resolution up to 1.5 times finer than the measured field.

Here we present a detailed analysis of the properties and evolution of different dwarf galaxies, candidate to host the coalescence of black hole binary systems (BHB) generating GW150914-like events. By adopting a novel theoretical framework coupling the binary population synthesis code \texttt{SeBa} with the Galaxy formation model \texttt{GAMESH}, we can investigate the detailed evolution of these objects in a well resolved cosmological volume of 4~cMpc, having a Milky Way-like (MW) galaxy forming at its center. We identify three classes of interesting candidate galaxies: MW progenitors, dwarf satellites and dwarf galaxies evolving in isolation. We find that: (i) despite differences in individual histories and specific environments the candidates reduce to only nine representative galaxies; (ii) among them, $\sim44\%$ merges into the MW halo progenitors by the redshift of the expected signal, while the remaining dwarfs are found as isolated or as satellites of the MW and their evolution is strongly shaped by both peculiar dynamical history and environmental feedback; (iii) a stringent condition for the environments where GW150914-like binaries can form comes from a combination of the accretion history of their DM halos and the radiative feedback in the high redshift universe; (iv) by comparing with the observed catalogues from DGS and ALLSMOG surveys we find two observed dwarfs respecting the properties predicted by our model. We finally note how the present analysis opens the possibility to build future strategies for host galaxy identification., MNRAS in press. Replaced with correct captions in figures A1 and A2 of the Appendix

In this study, the performance of antenna-pattern inversion methods is analysed focusing on applications related to the enhancement of the spatial resolution of passive microwave radiometer measurements. In particular, the projection of the reference field onto the kernel of the system function is analysed assuming different radiometer measurements configurations. The analysis shows that one can a priori obtain informations on the performance achievable using antenna pattern deconvolution techniques by analysing the projection of the reference field on the kernel associated to the system function. This allows understanding the role played by the constraints on the sought solution.

Spatial resolution enhancement of microwave radiometer measurements is addressed using a new method that is based on an $L^{p}$ penalisation approach with a variable $p$ exponent. The key idea is letting $p$ to vary in the range 1.2 - 2 to take benefit of both Hilbert (i.e. $p=2)$ and Banach (i.e. $p=1.2)$ advantages. Results, obtained processing both simulated and actual Special Sensor Microwave Imager (SSM/I) measurements, demonstrate the benefits of the proposed approach in reconstructing abrupt discontinuities and smooth gradients with respect to approaches in Hilbert and Banach spaces.

Plastic pollution in world oceans is estimated to have reached 270.000 tones, or 5.25 trillion pieces. This plastic is now ubiquitous, however due to ocean circulation patterns, it accumulates in the ocean gyres, creating “garbage patches”. This plastic debris is colonized by microorganisms which can create unique surfactants and bio-film ecosystems. Microbial colonization is the first step towards disintegration and degradation of plastic materials: a process that releases metabolic by-products from energy synthesis. These byproducts include the release of short-chain and more complex carbon molecules in the form of surfactants, which we hypothesize will affect the fluid dynamic properties of waves (change in viscosity and surface tension) and make them detectable by the SAR sensor. In this study we used Sentinel-1A and COSMO-SkyMed SAR images in selected sites of the North Pacific and North Atlantic oceans, close to the ocean gyres and away from the coastal interference. Together with SAR processing we conducted contextual image analysis, using ocean geophysical products of the sea surface temperature, surface wind, chlorophyll, wave heights and wave spectrum of the ocean surface. In addition, we started lab experiments under controlled conditions to test the behaviour of microbes colonizing the two most common marine pollutants, polyethylene (PE) and polyethylene terephthalate (PET) microplastics. The analysis of the SAR images had shown that a combination of surface wind speed and Langmuir cells- ocean circulation pattern is the main controlling factor in creating the distinct appearance of the surfactants, sea-slicks and microbial bio-films. The preliminary conclusion of our study is that SAR remote sensing may be able to detect plastic pollution in the open oceans and this method can be extended to other areas.

We present a novel approach to enhance the spatial resolution of microwave data collected by meso-scale sensors. The proposed rationale is based on an LP-penalization approach with a variable exponent p, ranging in the interval [1.5,2]. This allows taking benefits of the advantages of both Hilbert and Banach spaces. Preliminary experiments undertaken using simulated and actual radiometer data confirm the effective improvement in the signal reconstruction by using this approach with respect to conventional Hilbert and Banach-space methods.

We present a novel theoretical model to characterize the formation and coalescence sites of compact binaries in a cosmological context. This is based on the coupling between the binary population synthesis code SeBa with a simulation following the formation of a Milky Way-like halo in a well resolved cosmic volume of 4 cMpc, performed with the GAMESH pipeline. We have applied this technique to investigate when and where systems with properties similar to the recently observed LIGO/VIRGO events are more likely to form and where they are more likely to reside when they coalesce. We find that more than 70% of GW151226 and LVT151012-like systems form in galaxies with stellar mass M* > 10^8 Msun in the redshift range [0.06 - 3] and [0.14 - 11.3], respectively. All GW150914-like systems form in low-metallicity dwarfs with M* < 5 10^6 Msun at 2.4 < z < 4.2. Despite these initial differences, by the time they reach coalescence the observed events are most likely hosted by star forming galaxies with M* > 10^{10} Msun. Due to tidal stripping and radiative feedback, a non negligible fraction of GW150914-like candidates end-up in galaxies with properties similar to dwarf spheroidals and ultra-faint satellites., 6 pages, 3 figures, accepted by MNRAS after minor changes to the original version