Results 81 to 90 of about 15,217 (172)

Globally Critical Infrastructure: The Unique Risks and Challenges

Risk Analysis, Volume 45, Issue 12, Page 4804-4817, December 2025.
ABSTRACT Critical infrastructure is typically identified at the national level. However, disruption to certain infrastructure systems, facilities, and assets can have negative consequences for global societies. Such globally critical infrastructure entails a distinct risk profile for both countries dependent on the infrastructure, and countries that ...
Zachary Kallenborn, Henry H. Willis
wiley   +1 more source

Quantitative analysis of the tropospheric delay difference using empirical mapping functions on VLBI stations

Frontiers in Astronomy and Space Sciences
Tropospheric delay is a major error source for the high-accuracy Very Long Baseline Interferometry (VLBI) technique due to rapid water vapor variations. The Niell mapping function (NMF) and Global Mapping Function (GMF) are extensively applied to convert
W. L. Zhou, W. L. Zhou, W. L. Zhou, W. L. Zhou, S. L. Song, S. L. Song, J. Jiang, J. Jiang, X. Hu, P. J. Li, P. J. Li, Z. B. Zhang, Z. B. Zhang, Z. B. Zhang   +13 more
doaj   +1 more source

Extragalactic VLBI at 89 GHZ [PDF]

Symposium - International Astronomical Union, 1984
Radio interferometry at 89 GHz with transcontinental baselines can probe the region of active galaxies and quasars where collimation of relativistic outflows occur on length scales of 1017–18cm. Three experiments have been conducted recently to demonstrate the feasability and importance of this investigation.
openaire   +1 more source

Integration of Statistical Models and Deep Learning: A CEEMDAN‐Based Hybrid Framework for Frequency‐Domain Prediction of Polar Motion

Earth and Space Science, Volume 12, Issue 10, October 2025.
Abstract High‐precision Earth Rotation Parameter (ERP) products often experience delays that range from several days to weeks. The use of precise forecasting models can effectively compensate for the impact of such delays. Based on a systematic analysis of the forecasting capabilities of the traditional harmonic least squares fitting and autoregressive
Chen Ren, Chen Wang, Zhenhong Li, Haoran Gong, Jialiang Liu   +4 more
wiley   +1 more source

Estimation and Attribution of Horizontal Land Motion Measured by the Greenland GNSS Network

Journal of Geophysical Research: Solid Earth, Volume 130, Issue 9, September 2025.
Abstract Horizontal land motion, as observed by geodetic techniques such as Global Navigation Satellite Systems (GNSS), is generally dominated by tectonic plate movement. However, in regions that are currently or formerly glaciated, such as Greenland, the deformation of the solid Earth due to surface loading complicates the separation of tectonic and ...
D. Longfors Berg, S. Adhikari, J. Hassan, R. Steffen, H. Steffen, M. Willis, S. A. Khan   +6 more
wiley   +1 more source

A Review of Machine Learning‐Based Ionospheric Spatial and Temporal Modeling

Journal of Geophysical Research: Machine Learning and Computation, Volume 2, Issue 3, September 2025.
Abstract The ionosphere introduces disturbances and errors in radio signals for satellite communication and navigation, requiring precise modeling to mitigate these effects. However, accurate ionospheric modeling faces challenges due to the complex spatio‐temporal variations caused by intricate coupling with the lower atmosphere and Earth's magnetic ...
Shuyin Mao, Manuel Hernández‐Pajares, Benedikt Soja   +2 more
wiley   +1 more source

VLBI observations

Eos, Transactions American Geophysical Union, 1983
From the centers of quasars calculated to have velocities 10 times greater than that of light—the Einsteinian constant of the universe—astronomers are finding explanations of Doppler effect red shifts of emission. Very long baseline interferometry (VLBI) arrays have been used to examine the cores of seven known radio sources in space that are ...
openaire   +1 more source

Linking Planetary Ephemeris Reference Frames to ICRF via Millisecond Pulsars

Universe
The positions of millisecond pulsars (MSPs) can be determined with sub-milliarcsecond (mas) accuracy using both Very Long Baseline Interferometry (VLBI) and timing, referenced to the International Celestial Reference Frame (ICRF) and planetary ...
Li Guo, Yueqi Song, Zhen Yan, Liang Li, Guangli Wang   +4 more
doaj   +1 more source

Wide-field VLBI imaging

New Astronomy Reviews, 1999
We discuss the technique of Wide-field imaging as it applies to Very Long Baseline Interferometry (VLBI). In the past VLBI data sets were usually averaged so severely that the field-of-view was typically restricted to regions extending a few hundred milliarcseconds from the phase centre of the field.
Garrett, M. A., Porcas, R. W., Pedlar, A., Muxlow, T. W. B., Garrington, S. T.   +4 more
openaire   +2 more sources

Geodetic Evidence of Shallow Slow‐Slip Phenomena Beneath the Southern Ryukyu Forearc

Geophysical Research Letters, Volume 52, Issue 13, 16 July 2025.
Abstract While slow slip events (SSEs) are recognized as a ubiquitous phenomenon in subduction zones, accurately tracking the spatiotemporal distribution of shallow SSEs remains challenging. Here, we investigate the potential occurrence of shallow SSEs in the southern Ryukyu forearc at the western boundary of the Philippine Sea plate using 25 years of ...
Chi‐Hsien Tang, Ya‐Ju Hsu, Yutaro Okada, Yusaku Ohta, Takeshi Sagiya, Pei‐Ru Jian, Yoshiaki Tamura, Takaaki Jike   +7 more
wiley   +1 more source