Blar i Institutt for bygg- og miljøteknikk på forfatter "Nahavandchi, Hossein"
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On the Response of Polarimetric GNSS-Reflectometry to Sea Surface Roughness
Hoseini, Mostafa; Semmling, Maximilian; Nahavandchi, Hossein; Rennspiess, Erik; Ramatschi, Markus; Haas, Rüdiger; Strandberg, Joakim; Wickert, Jens (Journal article; Peer reviewed, 2021)Reflectometry of Global Navigation Satellite Systems (GNSS) signals from the ocean surface has provided a new source of observations to study the ocean-atmosphere interaction. We investigate the sensitivity and performance ... -
A Performance Assessment of Polarimetric GNSS-R Sea Level Monitoring in the Presence of Sea Surface Roughness
Rajabi, Mahmoud; Hoseini, Mostafa; Nahavandchi, Hossein; Semmling, Maximilian; Ramaschi, Markus; Goli, Mehdi; Hass, R ̈udiger; Wickert, Jens (Peer reviewed; Journal article, 2021)Monitoring coastal sea level has gained a large socioeconomic and environmental significance. Ground-based Global Navigation Satellite System Reflectometry (GNSS-R) offers various geophysical parameters including sea surface ... -
Persistent Scatterer Analysis Using Dual-Polarization Sentinel-1 Data: Contribution From VH Channel
Shamshiri, Roghayeh; Nahavandchi, Hossein; Motagh, Mahdi (Journal article; Peer reviewed, 2018)The regular acquisition and relatively short revisit time of Sentinel-1 satellite improve the capability of a persistent scatterer interferometric synthetic aperture radar (PS-InSAR) as a suitable geodetic method of choice ... -
Polarimetric GNSS-R Sea Level Monitoring using I/Q Interference Patterns at Different Antenna Configurations and Carrier Frequencies
Rajabi, Mahmoud; Hoseini, Mostafa; Nahavandchi, Hossein; Semmling, Maximillian; Ramatschi, Markus; Goli, Mehdi; Haas, Rudiger; Wickert, Jens (Peer reviewed; Journal article, 2021)Coastal sea level variation as an indicator of climate change is extremely important due to its large socioeconomic and environmental impacts. The ground-based global navigation satellite system (GNSS)-reflectometry (GNSS-R) ... -
The potential of spaceborne GNSS reflectometry for detecting ocean surface currents
Hoseini, Mostafa; Nahavandchi, Hossein (Peer reviewed; Journal article, 2022)The detectability of ocean surface currents in global navigation satellite system reflectometry (GNSS-R) observations is analyzed. We use a large dataset of spaceborne GNSS-R measurements from NASA cyclone GNSS (CYGNSS) ... -
Precise geoid determination over Sweden using the Stokes-Helmert method and improved topographic corrections
Nahavandchi, Hossein; Sjöberg, Lars Erik (Peer reviewed; Journal article, 2001)Four different implementations of Stokes's formula are employed for the estimation of geoid heights over Sweden: the Vincent and Marsh (1974) model with the high-degree reference gravity field but no kernel modifications; ... -
Quantifying groundwater exploitation induced subsidence in the Rafsanjan Plain, southeastern Iran, using InSAR time-series and in situ measurements
Motagh, Mahdi; Shamshiri, Roghayeh; Haghshenas-Haghighi, Mahmud; Wetzel, Hans-Ulrich; Akbari, Bahman; Nahavandchi, Hossein; Roessner, Sigrid; Arabi, Siavash (Journal article, 2017)Decades of groundwater overexploitation for agriculture and industrial development have resulted in substantial land subsidence in the Rafsanjan plain of southeastern Iran. This work presents the results of an InSAR time ... -
The Quest for a Precise Geoidal Height Model
Nahavandchi, Hossein (Peer reviewed; Journal article, 2004)The geoid is defined as an equipotential surface of the Earth�s actual gravity field inside the topographical masses on land (in most cases) and more or less coinciding with mean sea level at sea. Over the last decade, ... -
Recovery of marine gravity anomalies from ERS1, ERS2 and ENVISAT satellite altimetry data for geoid computations over Norway
Soltanpour, Ali; Nahavandchi, Hossein; Ghazavi, Kourosh (Peer reviewed; Journal article, 2007)Free-Air Anomalies (FAA) for the Norwegian marine area including some parts of the North Sea, the Norwegian Sea and the Barents Sea are computed from satellite altimetry data. A total of 84 cycles of ERS2 along-track data, ... -
Remote Sensing of Precipitation Using Reflected GNSS Signals: Response Analysis of Polarimetric Observations
Asgarimehr, Milad; Hoseini, Mostafa; Semmling, Maximilian; Ramatschi, Markus; Camps, Adriano; Nahavandchi, Hossein; Haas, Rüdiger; Wickert, Jens (Journal article; Peer reviewed, 2021)For the first time, rain effects on the polarimetric observations of the global navigation satellite system reflectometry (GNSS-R) are investigated. The physical feasibility of tracking the modifications in the surface ... -
Remote Sensing of Soil Moisture Using GNSS Reflectometry
Haneberg, Vegard; Rindal, Mads Engja (Master thesis, 2022)Forsterkende konsekvenser av klimaendringer fremhever behovet for overvåkning av jordens vannsykler over land, spesielt sett i sammenheng med økningen av naturkatastrofer som flom og tørke. Denne studien presenterer en ny ... -
Remote Sensing of Soil Moisture Using GNSS Reflectometry
Rindal, Mads Engja; Haneberg, Vegard (Master thesis, 2022)Forsterkende konsekvenser av klimaendringer fremhever behovet for overvåkning av jordens vannsykler over land, spesielt sett i sammenheng med økningen av naturkatastrofer som flom og tørke. Denne studien presenterer en ny ... -
Sammenligning av geoidens høyde utledet fra geopotensialmodellen EGM2008 med GPS/nivellementsdata i et testområde i Iran (Comparison of geoid heights from the EGM2008 geopotential model and GPS/levelling data in a study area in Iran)
Nahavandchi, Hossein; Mahdavipour, Hossein (Peer reviewed; Journal article, 2012)The global Earth Gravity Model EGM2008 is evaluated locally using Global Positioning System (GPS)/levelling data in a test area in Iran. The non-tidal release of the EGM2008 is used in the computations. An indirect approach ... -
Sea Ice Segmentation in Sentinel-1 Imagery using a Convolutional Neural Network
Ledsaak, Sigrid Marie Eie; Brask, Nora Strømberg (Master thesis, 2021)Den Arktiske havisen er avgjørende for det globale miljøet og representerer en betydelig utfordring for navigering i polare områder. Derfor har overvåking av havis blitt et viktig ansvar for statene som ligger innenfor ... -
Sea Ice Segmentation in Sentinel-1 Imagery using a Convolutional Neural Network
Ledsaak, Sigrid Marie Eie; Brask, Nora Strømberg (Master thesis, 2021)Den Arktiske havisen er avgjørende for det globale miljøet og representerer en betydelig utfordring for navigering i polare områder. Derfor har overvåking av havis blitt et viktig ansvar for statene som ligger innenfor ... -
Seasonal variation analysis of Greenland ice mass time-series
Shamshiri, Roghayeh; Nahavandchi, Hossein; Joodaki, Gholamreza (Journal article; Peer reviewed, 2017)We derive the mass balance of Greenland ice sheet from the Gravity Recovery and Climate Experiment (GRACE) for the period January 2003–October 2014. We have found an ice mass loss with peak amplitude of −15 cm/yr in the ... -
Seasonal variation analysis of Greenland ice mass time-series
Shamshiri, Roghayeh; Nahavandchi, Hossein; Joodaki, Gholamreza (Journal article, 2018)We derive the mass balance of Greenland ice sheet from the gravity recovery and climate experiment (GRACE) for the period January 2003 to October 2014. We find an ice mass loss with peak amplitude of -15 cm/year in the ... -
Steric sea level changes from ENVISAT and GRACE in the Nordic Seas
Joodaki, Gholamreza; Nahavandchi, Hossein; Ghazavi, Kourosh (Peer reviewed; Journal article, 2013)Steric sea level changes are estimated over the Nordic Seas using ENVISAT (Environmental Satellite) altimetry and GRACE (Gravity Recovery and Climate Experiment) gravity data. We have used altimetry data from the ENVISAT ... -
A Technical Note on Least Squares Mascon Fitting to GRACE Satellite Data to Estimate Total Water Storage Changes in the Middle East
Safdari, Zohreh; Joodaki, Gholamreza; Nahavandchi, Hossein (Chapter, 2022)Nowadays the twin satellite gravimetry missions, GRACE (Gravity Recovery and Climate Experiment) and GRACE -Follow On, provide a unique and alternative tool for monitoring and measuring Total Water Storage (TWS) changes ... -
The Application of Spaceborne GNSS-Reflectometry for the Study of Ocean Microplastics
Strand, Andreas Gaustadnes (Master thesis, 2021)Fra produksjonen av oksygen, mat og medisin til transport og maritim økonomi, spiller verdenshavene en avgjørende rolle i det menneskelige samfunn. Over flere tiår har fjernmåling satellitter overvåket havene ved hjelp av ...