Anders Carlström

Influence of ice and snow properties on ice ridge mapping by SAR

Anders Carlström, Lars M. H. Ulander, Wolfgang Dierking

Effects of different ice and snow properties on the signature of ice ridges in ERS-1 SAR images are investigated. Scattering models based on the physical optics approximation are applied to surface backscatter from ice ridges and frozen brash ice. In situ ice …

Advancing GNSS-RO Detection of Ionospheric Irregularities Using Refined Back Propagation and GOLD Data

Carles Quilis Alfonso, Vinícius Ludwig‐Barbosa, Joel Rasch, Anders Carlström et autres

This paper investigates on the detection and localization of ionospheric irregularities using GNSS Radio Occultation (GNSS-RO).We propose a new segmented phase screen (PS) approach to improve vertical and horizontal localization and remove the presence of outliers.The study focused on the May 2024 …

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The GRAS-2 radio occultation mission

Joel Rasch, Anders Carlström, Jacob Højgaard Christensen, Thomas Liljegren

The second generation of the Global navigation satellite system Receiver for Atmospheric Sounding (GRAS-2) is a radio occultation (RO) instrument which is capable of providing 2000 atmospheric profiles per day. The instrument is hosted on all satellites in the MetOp Second Generation …

Back Propagation Method for the Determination of the Vertical Location of Ionospheric Irregularities

Carles Quilis Alfonso, Vinícius Ludwig‐Barbosa, Joel Rasch, Anders Carlström et autres

This study presents a new back-propagation (BP) method to determine the vertical location of ionospheric irregularities using GNSS Radio Occultation (GNSS-RO) signals. GNSS-RO employs signals from GNSS satellites intercepted by Low Earth Orbit (LEO) satellites to gather data about different atmospheric layers, …

The GRAS-2 Radio Occultation Mission

Joel Rasch, Anders Carlström, Jacob Højgaard Christensen, Thomas Liljegren

Abstract. The second generation of the Global navigation satellite system Receiver for Atmospheric Sounding (GRAS-2) is a Radio Occultation (RO) instrument which is capable of providing 2000 atmospheric profiles per day. The instrument is hosted on all satellites in the Metop Second …

Location of Ionospheric Irregularities in Extended GNSS-RO Measurements Using Back Propagation Method

Vinícius Ludwig‐Barbosa, Joel Rasch, Anders Carlström, Jacob Højgaard Christensen et autres

Besides providing electron density profiles (EDP), GNSS Radio Occultation (GNSS-RO) measurements allow monitoring the frequency and the areas where ionospheric scintillations occur. In this work, RO measurements composing an experimental data set are processed with the back propagation (BP) method to estimate …

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Sea Surface Roughness Determination from Grazing Angle GPS Ocean Observations and Scatterometry Simulations

Per Høeg, Anders Carlström

Measurements of grazing angle GNSS-R ocean reflections combined with meteorological troposphere data are used for retrieval of ocean wave heights and surface roughness parameters. The observational results are compared to multiphase screen simulations for the same atmosphere conditions. The retrieved data from …

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Detection and localization of F-layer ionospheric irregularities with the back-propagation method along the radio occultation ray path

Vinícius Ludwig‐Barbosa, Joel Rasch, Thomas Sievert, Anders Carlström et autres

The back-propagation (BP) method consists of diffractive integrals computed over a trajectory path, projecting a signal to different planes. It unwinds the diffraction and multipath, resulting in minimum disturbance to the BP amplitude when the auxiliary plane coincides with the region causing …

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Detection and Localization of F-layer Ionospheric Irregularities with Back Propagation Method Along Radio Occultation Ray Path

Vinícius Ludwig‐Barbosa, Joel Rasch, Thomas Sievert, Anders Carlström et autres

Abstract. The back propagation (BP) method consists of diffractive integrals computed over a trajectory path, projecting a signal to different planes. It unwinds the diffraction and multipath, resulting in minimum disturbance on the BP amplitude when the auxiliary plane coincides with the …

se (code pays fourni par la source)

Supervised Detection of Ionospheric Scintillation in Low-Latitude Radio Occultation Measurements

Vinícius Ludwig‐Barbosa, Thomas Sievert, Anders Carlström, Mats Ingemar Pettersson et autres

Global Navigation Satellite System (GNSS) Radio Occultation (RO) has provided high-quality atmospheric data assimilated in Numerical Weather Prediction (NWP) models and climatology studies for more than 20 years. In the satellite–satellite GNSS-RO geometry, the measurements are susceptible to ionospheric scintillation depending on …

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Using A Sliding Window Phase Matching Method for Imaging of GNSS Radio Occultation Signals

Thomas Sievert, Joel Rasch, Anders Carlström, Vinícius Ludwig‐Barbosa et autres

Global Navigation Satellite System Radio Occultation (GNSS-RO) is a technique used to sound the atmosphere and derive vertical profiles of refractivity. Signals from GNSS satellites are received in a low-Earth orbit, and they are then processed to produce bending angle profiles, from …

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Evaluation of Ionospheric Scintillation in GNSS Radio Occultation Measurements and Simulations

Vinícius Ludwig‐Barbosa, Thomas Sievert, Joel Rasch, Anders Carlström et autres

Abstract Like any other system relying on transionospheric propagation, Global Navigation Satellite System (GNSS) Radio Occultation (GNSS‐RO) is affected by ionospheric conditions during measurements. Regions of plasma irregularities in F region create abrupt gradients in the distribution of ionized particles. Radio signals …

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