Boundary Between Earth’s Upper Atmosphere And Space Has Moved To Extraordinarily Low Altitudes, NASA Instruments Document
Recent measurements by NASA instruments indicate that the “transition between the ionosphere and space was found to be at about 260 miles (420 km) altitude during the nighttime, barely rising above 500 miles (800 km) during the day. These altitudes were extraordinarily low compared with the more typical values of 400 miles (640 km) during the nighttime and 600 miles (960 km) during the day.”
The Physical Environment Link – Atmospheric Structure
Abrupt Climate Change: Will It Happen This Century?
A new USGS report indicates that the United States faces the potential for abrupt climate change in the 21st century. The report is based on an assessment of the published science literature and came to the following conclusions:
- Climate model simulations and observations suggest that rapid and sustained September arctic sea ice loss is likely in the 21st century.
- The southwestern United States may be beginning an abrupt period of increased drought.
- It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25-30 percent. However, it is very unlikely that this circulation will collapse or that the weakening will occur abruptly during the 21st century and beyond.
- An abrupt change in sea level is possible, but predictions are highly uncertain due to shortcomings in existing climate models.
- There is unlikely to be an abrupt release of methane, a powerful greenhouse gas, to the atmosphere from deposits in the earth. However, it is very likely that the pace of methane emissions will increase.
Article at USGS Newsroom
The Physical Environment Link – Climate Systems
Changes ‘amplify Arctic warming’
The BBC is reporting on a presentation made by Julienne Stroeve of the US National Snow and Ice Data Center to the American Geophysical Union that decreasing sea ice is amplifying the temperature changes in the northern polar regions. This seems to validate what computer models have long predicted.
Article at BBC News
The Physical Environment Link – Climate Change: Global Warming
Drillers Accidentally Create First Live Magma Observatory
Drillers accidentally punctured a pocket of magma underneath a geothermal field in Hawaii giving geologists a look into a live magma chamber.
Article at Wired Science
The Physical Environment Link: Features of Volcanoes