Task Groups
From CAWSES
CAWSES II is organized around Task Groups
Task 1: What are the solar influences on the Earth’s climate?
Solar variability drives geo-space and the atmosphere on time scales ranging from minutes to millennia. Feedbacks are inherent in the Earth system and may amplify the direct forcing effects from the Sun. The influence of this solar variability on Earth’s climate is a key issue of the Intergovernmental Panel on Climate Change, and one that continues to be highlighted by policy makers, climate change skeptics, and the media.
Task 2: How will geospace respond to an altered climate?
Radiative, chemical, and dynamical forcing from below contributes to disturbances of the upper atmosphere. In response to rising greenhouse gas concentrations, cooling in the middle atmosphere will alter the complex physical and chemical processes of this region. Patterns of cooling and contraction of the upper atmosphere are emerging from model studies and observations, consistent with a strong connection to changes in the lower atmosphere. Recent changes in noctilucent cloud distributions, now observed on a global scale by the AIM satellite (see figure above), are thought to be symptomatic of cooling temperatures in the upper atmosphere. Rising greenhouse gas concentrations alter the ionosphere in a variety of ways and could be transmitted to the magnetosphere. These changes may have unforeseen consequences for space-related technologies and societal infrastructures.
Task 3: How does short-term solar variability affect the geospace environment?
Solar variations such as solar flares, energetic particle bursts, coronal mass ejections, and high-speed solar wind streams directly alter space weather on short time scales. Electromagnetic radiation drives the ionosphere, while solar particulate outputs penetrate through space, interact with the magnetosphere and upper-middle atmospheres, and even produce disturbances at Earth’s surface. A systems approach is crucial to understand and forecast space weather.
Task 4: What is the geospace response to variable waves from the lower atmosphere?
A variety of new evidence suggests that tropospheric weather is an important ingredient in space weather. Equatorial ionospheric densities are modulated by atmospheric waves driven by persistent tropical rainstorms. The figure (right) shows enhanced airglow from these regions of elevated density. Radio waves generated by lightning strokes in the rainstorms interact with radiation belt particles to clear a "safe" zone between the inner and outer belts in the magnetosphere. Gravity waves generated by hurricanes and typhoons may seed plasma bubbles in the low latitude ionosphere. The extent to which the effects of this quiescent atmospheric variability are transmitted to the magnetosphere is yet to be resolved.
