scholarly journals Wind and temperature effects on thermosphere mass density response to the November 2004 geomagnetic storm

2010 ◽  
Vol 115 (A5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jiuhou Lei ◽  
Jeffrey P. Thayer ◽  
Alan G. Burns ◽  
Gang Lu ◽  
Yue Deng
Keyword(s):  
Geomagnetic Storm ◽  
Temperature Effects ◽  
Mass Density ◽  
Density Response

scholarly journals Correction to “Wind and temperature effects on thermosphere mass density response to the November 2004 geomagnetic storm”

2010 ◽  
Vol 115 (A6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Jiuhou Lei ◽  
Jeffrey P. Thayer ◽  
Alan G. Burns ◽  
Gang Lu ◽  
Yue Deng
Keyword(s):  
Geomagnetic Storm ◽  
Temperature Effects ◽  
Mass Density ◽  
Density Response

scholarly journals Effect of Temperature on Stiffness of Sandstones from the Deep North Sea Basin

2020 ◽  
Author(s):  
Tobias Orlander ◽  
Katrine Alling Andreassen ◽  
Ida Lykke Fabricius
Keyword(s):  
North Sea ◽  
Temperature Effects ◽  
Mass Density ◽  
Thermal Strain ◽  
High Stress ◽  
Testing Temperature ◽  
Effect Of Temperature ◽  
Stress Regime ◽  
The North

Abstract Development of high-pressure, high-temperature (HPHT) petroleum reservoirs situated at depths exceeding 5 km and in situ temperature of 170 °C increases the demand for theories and supporting experimental data capable of describing temperature effects on rock stiffness. With the intention of experimentally investigating temperature effects on stiffness properties, we investigated three sandstones from the deep North Sea Basin. As the North Sea Basin is presently undergoing substantial subsidence, we assumed that studied reservoir sandstones have never experienced higher temperature than in situ. We measured ultrasonic velocities in a low- and high-stress regime, and used mass density and stress–strain curves to derive, respectively, dynamic and static elastic moduli. We found that in both regimes, the dry sandstones stiffens with increasing testing temperature and assign expansion of minerals as a controlling mechanism. In the low-stress regime with only partial microcrack closure, we propose closure of microcracks as the stiffening mechanism. In the high-stress regime, we propose that thermal expansion of constituting minerals increases stress in grain contacts when the applied stress is high enough for conversion of thermal strain to thermal stress, thus leading to higher stiffness at in situ temperature. We then applied an extension of Biot’s effective stress equation including a non-isothermal term from thermoelastic theory and explain test results by adding boundary conditions to the equations.

Analysis of a severe geomagnetic storm on August 26, 2018 and the related effects on the GRACE-FO mission

2020 ◽  
Author(s):  
Sandro Krauss ◽  
Manuela Temmer ◽  
Saniya Behzadpour ◽  
Christoph Lhotka
Keyword(s):  
Geomagnetic Storm ◽  
Mass Density ◽  
Field Measurements ◽  
Major Axis ◽  
Satellite Mission ◽  
Interplanetary Coronal Mass Ejections ◽  
Semi Major Axis ◽  
Solar Observations ◽  
Magnetic Field Measurements ◽  
Orbit Decay

<p>On August 20, 2018 a complex interplanetary coronal mass ejections (ICME) occurred on the Sun, which subsequently triggered an unexpected large geomagnetic storm on August 25. We present a detailed analysis of the ICME eruption and explore the occurred perturbation of the neutral mass density in the upper Earth's atmosphere. The analysis is based on accelerometer observations from the satellite mission GRACE Follow-On as well as interplanetary magnetic field measurements by the DSCOVR and ACE spacecraft. Through the evaluation of solar observations by the SECCHI instrument on-board of the STEREO-A satellite in form of white-light, the early evolution of the ICME can be aptly illustrated. Furthermore, due to the heating and the subsequent expansion of the thermosphere also the drag force acting on the spacecraft is enhanced. This leads to an additional storm induced orbit decay, which we calculate by means of variations in the semi-major axis. The findings are compared with predictions from our preliminary thermospheric forecasting tool, which is based on the study by Krauss et al. 2018.</p>

Sign in / Sign up

Export Citation Format

Share Document