In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone. There is so much oxygen in our atmosphere, that these high-energy ultraviolet rays are completely absorbed in the stratosphere.
On the stage of global change, ozone plays the role of both hero and villain. This brief document discusses about the tracking of Tropospheric Ozone, where ozone forms and where it travels have become key concerns for international health and economic policy-making.
This feature article provides a summary of study about the role of clouds in the balance. Until recently, scientists were uncertain whether clouds had an overall net cooling or heating effect on the Earth's climate. But recent studies show that, in the tropics, a "near cancellation" between shortwave cooling and longwave warming exists, which indicates that the amount of incoming radiant energy is roughly equal to the amount of outgoing radiation. However, small changes in tropical cloudiness can disrupt this precarious balance.
The amount and distribution of ozone molecules in the stratosphere varies greatly over the globe. Ozone molecules are transported around the stratosphere much as water clouds are transported in the troposphere. Therefore, scientists observing ozone fluctuations over just one spot could not know whether a change in local ozone levels meant an alteration in global ozone levels, or simply a fluctuation in the concentration over that particular spot. Satellites have given scientists the ability to overcome this problem because they provide a picture of what is happening daily over the entire Earth.
Large fires can be blamed for some polluted air. In addition to ash and smoke, fires release carbon monoxide into the atmosphere as they burn. This false-color image shows the atmospheric column of carbon monoxide, with yellow and red indicating high levels of pollution. (The gray areas show where no data were taken, likely due to cloud cover.) The data were taken by the Measurements Of Pollution In The Troposphere (MOPITT) instrument aboard NASA's Terra satellite for the period October 26-31, 2003.
Remarks by NASA Administrator Sean O'Keefe at the 2003 Earth Observation Summit in Washington, DC. The purpose of the summit was to promote the development of a comprehensive, coordinated, and sustained Earth observation system or systems among governments and the international community to understand and address global environmental and economic challenges, and also to begin a process to develop a conceptual framework and implementation plan for building this integrated Earth observation system. When the space age dawned it was clear that the ability to propel robotic spacecraft and humans beyond the gravity of our home planet would open up untold avenues of exploration and discovery throughout the Solar System and beyond. What was not understood at the time was how comprehensive observations of the Earth system from space would lead to a significant new field of scientific inquiry.
Researchers at NASA and the University of Maryland, Baltimore County (UMBC), studying changes in tropical precipitation patterns, have noted a higher frequency of El Niños and La Niñas over the last 21 years. In addition, when either of those events occur, the world can expect more months with unusually high or low precipitation with droughts more common than floods over land areas.