Space Physics and Aeronomy, Upper Atmosphere Dynamics and Energetics
Wenbin Wang, Yongliang Zhang, Wenbin Wang
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Space Physics and Aeronomy, Upper Atmosphere Dynamics and Energetics
Wenbin Wang, Yongliang Zhang, Wenbin Wang
About This Book
A comprehensive overview of the structure and variability of the upper atmosphere
Earth's upper atmosphere is an open system that is strongly influencedby energy and momentum inputs from both above and below. New observation and modeing techniques have provided insights into dynamics, energetics, and chemical processes in the upper atmosphere.
Upper Atmosphere Dynamics and Energetics presents an overview of keyresearch advances in upper atmospheric physics, and measurement and modeling techniques, along with remaining challenges for understanding the state and variability of the upper atmospheric system.
Volume highlights include:
- Insights into the interconnections between different areas of upper atmospheric science
- Appreciation of the dynamics and complexity of the global upper atmospheric system
- Techniques for observing and measuring the upper atmosphere
- Responses of the upper atmosphere to external drivers
The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.
Find out more about the Space Physics and Aeronomy collection in this Q&A with the Editors in Chief
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Part I
Energetics and Dynamics of the Upper Atmosphere
1
Joule Heating in the Thermosphere
ABSTRACT
Highâlatitude Joule heating is an important energy source for thermospheric dynamics and composition. It is influenced by winds, plasma turbulence, variable electric fields, and conductivity modifications by strong electric fields. The heightâintegrated heating can be estimated from the Poynting flux above the ionosphere. Most energy is deposited near the morning and afternoon/evening sides of the auroral oval and in the cusp region. Multiâinstrument data assimilation can help quantify complex spatial/temporal variations of Joule heating. Rapid changes of heating launch gravity waves that propagate globally. Within several hours, a global circulation sets up that reduces horizontal variations of the pressure scale height, causing spatial correlation between the temperature and the mean molecular mass. The distributions of temperature and density in the upper thermosphere often show little relation to the distribution of Joule heating. Vertical winds decrease the O/N2 ratio in regions of heating and increase the ratio in regions of subsidence. The upper thermosphere is affected more strongly by the fraction of Joule heating deposited above 150 km than by the larger amount of Joule heating deposited below 150 km.