Results 21 to 30 of about 150 (111)

Calibration and Validation for the Surface Biology and Geology (SBG) Mission Concept: Recommendations for a Multi‐Sensor System for Imaging Spectroscopy and Thermal Imagery

Journal of Geophysical Research: Biogeosciences, Volume 128, Issue 9, September 2023., 2023
Abstract The primary objective of the National Aeronautics and Space Administration (NASA) Surface Biology and Geology (SBG) mission is to measure biological, physical, chemical, and mineralogical features of the Earth's surface, realizing a key conceptual component of the envisioned NASA Earth System Observatory (ESO).
Kevin R. Turpie, Kimberly A. Casey, Christopher J. Crawford, Liane S. Guild, Hugh Kieffer, Guoqing (Gary) Lin, Raymond Kokaly, Alok K. Shrestha, Cody Anderson, Shankar N. Ramaseri Chandra, Robert Green, Simon Hook, Constantine Lukashin, Kurt Thome   +13 more
wiley   +1 more source

COVID‐19 and income profile: How communities in the United States responded to mobility restrictions in the pandemic's early stages

Regional Science Policy &Practice, Volume 15, Issue 3, Page 541-558, April 2023., 2023
Abstract Mobility interventions in communities play a critical role in containing a pandemic at an early stage. The real‐world practice of social distancing can enlighten policymakers and help them implement more efficient and effective control measures. A lack of such research using real‐world observations initiates this article.
Qianqian Sun, Weiyi Zhou, Aliakbar Kabiri, Aref Darzi, Songhua Hu, Hannah Younes, Lei Zhang   +6 more
wiley   +1 more source

Neural ODE Differential Learning and Its Application in Polar Motion Prediction

Journal of Geophysical Research: Solid Earth, Volume 127, Issue 11, November 2022., 2022
Abstract This paper introduces a new learning algorithm for accurate, physically driven time series prediction. The fundamental assumption behind the method is that the phenomena follow Ordinary Differential Equations. We investigate the general case where the time series follows an ODE of degree .
Mostafa Kiani Shahvandi, Matthias Schartner, Benedikt Soja   +2 more
wiley   +1 more source

Estimation of Earth Rotation Parameters and Prediction of Polar Motion Using Hybrid CNN–LSTM Model

Remote Sensing, 2023
The Earth rotation parameters (ERPs), including polar motion (PMX and PMY) and universal time (UT1-UTC), play a central role in functions such as monitoring the Earth’s rotation and high-precision navigation and positioning.
Kehao Yu, Kai Yang, Tonghui Shen, Lihua Li, Haowei Shi, Xu Song   +5 more
doaj   +1 more source

Deriving Ionospheric Total Electron Content by VLBI Global Observing System Data Analysis During the CONT17 Campaign

Radio Science, Volume 57, Issue 9, September 2022., 2022
Abstract This article focuses on the new generation of geodetic very long baseline interferometry (VLBI), the VLBI global observing system (VGOS), and measurements carried out during the CONT17 campaign. It uses broadband technology that increases both the number and precision of observations.
Sanam Motlaghzadeh, M. Mahdi Alizadeh, Roger Cappallo, Robert Heinkelmann, Harald Schuh   +4 more
wiley   +1 more source

Improving Atmospheric Angular Momentum Forecasts by Machine Learning

Earth and Space Science, Volume 8, Issue 12, December 2021., 2021
Abstract Earth angular momentum forecasts are naturally accompanied by forecast errors that typically grow with increasing forecast length. In contrast to this behavior, we have detected large quasi‐periodic deviations between atmospheric angular momentum wind term forecasts and their subsequently available analysis.
R. Dill, J. Saynisch‐Wagner, C. Irrgang, M. Thomas   +3 more
wiley   +1 more source

Scale Factors of the Thermospheric Density: A Comparison of Satellite Laser Ranging and Accelerometer Solutions

Journal of Geophysical Research: Space Physics, Volume 126, Issue 12, December 2021., 2021
Abstract A major problem in the precise orbit determination (POD) of satellites at altitudes below 1,000 km is the modeling of the aerodynamic drag which mainly depends on the thermospheric density and causes the largest non‐gravitational acceleration. Typically, empirical thermosphere models are used to calculate density values at satellite positions ...
Lea Zeitler, Armin Corbin, Kristin Vielberg, Sergei Rudenko, Anno Löcher, Mathis Bloßfeld, Michael Schmidt, Jürgen Kusche   +7 more
wiley   +1 more source

Geodetic Datum Realization Using SLR‐GNSS Co‐Location Onboard Galileo and GLONASS

Journal of Geophysical Research: Solid Earth, Volume 126, Issue 10, October 2021., 2021
Abstract Modern satellites of Global Navigation Satellite Systems (GNSS) are equipped with laser retroreflector arrays for Satellite Laser Ranging (SLR). Laser range observations to GNSS satellites allow for the co‐location of two space geodetic techniques onboard navigation satellites.
G. Bury, K. Sośnica, R. Zajdel, D. Strugarek, U. Hugentobler   +4 more
wiley   +1 more source

Polar Coordinates and UT1 - UTC from PZT Observations [PDF]

Symposium - International Astronomical Union, 1979
Use of new techniques (Doppler, laser, VLBI) has yielded such results that many astronomers believe that in the near future these techniques will replace classical instruments for observations of the Earth's rotation. None of the modern techniques has furnished observational series which demonstrate that systematic errors in the polar coordinates and ...
openaire   +1 more source

Precise real‐time navigation of LEO satellites using GNSS broadcast ephemerides

NAVIGATION, Volume 68, Issue 2, Page 419-432, Summer 2021., 2021
Abstract The availability of orbit information with high precision and low latency is a key requirement for many Earth‐observation missions, predominantly in the field of radio occultation. Traditionally, precise orbit determination solutions of low‐Earth orbit (LEO) satellites are obtained offline on ground after downloading GNSS measurements and ...
André Hauschild, Oliver Montenbruck
wiley   +1 more source