Blar i NTNU Open på forfatter "Nahavandchi, Hossein"
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Greenland ice mass balance using GRACE gravity data
Schwartz, Vegar (Master thesis, 2014)The mass balance of Greenland has been assessed with data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Monthly data has been used through the time span of the study; January 2003 - December ... -
Greenland ice-melt spread into Northwest Coast revealed by GRACE (GRACE data viser at issmeltingen på Grønland sprer seg til nordvestkysten)
Nahavandchi, Hossein; Joodaki, Gholamreza (Peer reviewed; Journal article, 2012)We examine the extent and magnitude of Greenland ice sheet surface melting between 2002 and 2010. We show that the well documented Greenland ice mass loss in the southern region spread to northwest Greenland in the period ... -
Greenland mass balance estimation from satellite gravity measurements
Joodaki, Gholamreza; Nahavandchi, Hossein (Peer reviewed; Journal article, 2010)The Gravity Recovery and Climate Experiment (GRACE) data is used to estimate the secular trend and periodic variations of ice mass variability over Greenland. To do this, we use 92 monthly GRACE level 2 Release-04 (RL04) ... -
Groundwater Level Monitoring across Iran’s Main Water Basins Using Temporal Satellite Gravity Solutions and Well Data
Safdari, Zohreh (Doctoral theses at NTNU;2021:377, Doctoral thesis, 2021)Water is an essential resource for life on the earth; no life can exist without water. During recent decades, because of growth in population and technologies, demands for water resources have been increasing. Due to ... -
Improved determination of heights using a conversion surface by combining gravimetric quasi-geoid/geoid and GPS-levelling height differences
Nahavandchi, Hossein; Soltanpour, Ali (Peer reviewed; Journal article, 2006)The quasi-geoid/geoid can be determined from the Global Positioning System (GPS) ellipsoidal height and the normal/orthometric heights derived from levelling (GPS-levelling). In this study a gravimetric quasigeoid and ... -
Improving tropospheric corrections on large-scale Sentinel-1 interferogramsusing a machine learning approach for integration with GNSS-derived zenithtotal delay (ZTD)
Shamshiri, Roghayeh; Motagh, Mahdi; Nahavandchi, Hossein; Haghshenas, Mahmud; Hoseini, Mostafa (Peer reviewed; Journal article, 2020)Sentinel-1 mission with its wide spatial coverage (250 km), short revisit time (6 days), and rapid data dissemination opened new perspectives for large-scale interferometric synthetic aperture radar (InSAR) analysis. ... -
Increasing the Accuracy of Positioning in Mobile Mapping Systems - A method supported by Simultaneous Localization And Mapping
Løvås, Marianne (Master thesis, 2017)In areas where GNSS satellite signals become weak or unavailable a period of time, accuracy of the positioning of mobile mapping systems based in aided inertial navigation can be drastically reduced. This can be problematic ... -
Investigating Positional Accuracies from unsynchronized independent measurements for autonomous cooperative intelligent transportation systems
Lange, David Sebastian (Master thesis, 2018)Positional real-time data is an important part of a cooperative intelligent transportation system (C-ITS). In order to maneuver and control such an environment safely and efficiently, each autonomous traffic participant ... -
Local ionospheric modelling of GPS code and carrier phase observations
Nahavandchi, Hossein; Soltanpour, Ali (Peer reviewed; Journal article, 2008)A limiting factor for successful ambiguity resolution in precise GPS positioning is the existence of un-modelled ionospheric errors in both the carrier phase and the pseudorange measurements. In this study, the ionospheric ... -
Mass balance and mass loss acceleration of the Greenland ice sheet (2002 – 2011) from GRACE gravity data
Joodaki, Gholamreza; Nahavandchi, Hossein (Journal article; Peer reviewed, 2012)We examine the magnitude and acceleration of the Greenland ice sheet mass loss between 2002 and 2011. We use monthly observations of time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellite ... -
Mass loss of the Greenland ice sheet from GRACE time-variable gravity measurements
Joodaki, Gholamreza; Nahavandchi, Hossein (Peer reviewed; Journal article, 2012)The Gravity Recovery and Climate Experiment (GRACE) satellite data is used to estimate the rate of ice mass variability over Greenland. To do this, monthly GRACE level 2 Release-04 (RL04) data from three different processing ... -
Mean Sea Surface and ocean circulation in North Atlantic and the Arctic Sea
Ghazavi, Kourosh; Nahavandchi, Hossein (Journal article; Peer reviewed, 2011)High resolution Mean Sea Surface (MSS) model and its error estimation over the study region (56°N -
Modeling and Prediction of Regular Ionospheric Variations and Deterministic Anomalies
Rajabi, Mahmoud; Amiri‐Simkooei, Alireza; Nahavandchi, Hossein; Nafisi, Vahad (Journal article; Peer reviewed, 2020)Knowledge on the ionospheric total electron content (TEC) and its prediction are of great practical importance and engineering relevance in many scientific disciplines. We investigate regular ionospheric anomalies and TEC ... -
Multi-sensor InSAR analysis of surface displacement over coastal urban city of Trondheim
Shamshiri, Roghayeh; Nahavandchi, Hossein; Motagh, Mahdi; Haghshenas, Mahmud (Peer reviewed; Journal article, 2016)In this study, we present maps of ground surface displacement of the coastal urban city of Trondheim in central Norway using observations from interferometry synthetic aperture radar (InSAR). We used 98 SAR images including ... -
Multi-temporal interferometry (MTI) techniques for ground deformation mapping using Sentinel-1 SAR data
Shamshiri, Roghayeh (Doctoral theses at NTNU;2019:153, Doctoral thesis, 2019)The multi-temporal interferometry (MTI) techniques, such as persistent scatterer interferometric synthetic aperture radar (PS-InSAR) and small baseline (SBAS) have proved to be powerful geodetic tools to measure deformations ... -
A new strategy for the atmospheric gravity effect in gravimetric geoid determination
Nahavandchi, Hossein (Journal article; Peer reviewed, 2004)Prior to Stokes integration, the gravitational effect of atmospheric masses must be removed from the gravity anomaly g. One theory for the atmospheric gravity effect on the geoid is the well-known International Association ... -
Ocean Wave Measurement Using GPS Buoys
Joodaki, Gholamreza; Nahavandchi, Hossein; Cheng, Kevin (Journal article; Peer reviewed, 2013)The observation of ocean wave parameters is necessary to improve forecasts of ocean wave conditions. In this paper, we investigate the viability of using a single GPS receiver to measure ocean-surface waves, and present a ... -
On some methods of downward continuation of mean free-air gravity anomaly
Nahavandchi, Hossein (Journal article, 1998)This paper investigates four methods of downward continuation of free-air gravity anomalies to sea-level, an iterative process based on the Poisson's integral, a linear simple formula, a method based on the Pellinen ... -
On the Feasibility of Real-time Sea Level Monitoring using Ground-based GNSS-Reflectometry Measurements
Leikvoll, Magnus (Master thesis, 2020)GNSS Reflektometri (GNSS-R) er en fjernmålingsteknikk som har fått mye oppmerksomhet i nyere tid. I denne avhandlingen blir teorien bak GNSS reflektometri presentert, og et eksperiment er gjennomført for å vurdere mulighetene ... -
On the Remote Sensing of the Atmosphere and Ocean Using Direct and Reflected GNSS Signals
Hoseini, Mostafa (Doctoral thesis, 2022)The Global Navigation Satellite Systems (GNSS) signals have shown great potential for remote sensing applications. The ubiquitous GNSS signals in direct or reflected geometry can be processed to retrieve different geophysical ...