NOAA's National Weather Service will use a new hurricane scale this season called the Saffir-Simpson Hurricane Wind Scale. The scale keeps the same wind speed ranges as the original Saffir-Simpson Scale for each of the five hurricane categories, but no longer ties specific storm surge and flooding effects to each category.

Herbert Saffir, a consulting engineer, and Robert Simpson, who was director of the National Hurricane Center from 1967 through 1973, developed the original scale which was a useful tool to convey the threats of tropical cyclones. Changes were made to the Saffir-Simpson Scale because storm surge values and associated flooding are dependent on a combination of the storm's intensity, size, motion and barometric pressure, as well as the depth of the near-shore waters and local topographical features. As a result, storm surge values can be significantly outside the ranges suggested in the original scale.

For example, Hurricane Ike in 2008 was a very large storm that made landfall on the upper Texas coast as a Category 2 hurricane with a peak storm surge of 15 to 20 feet. In contrast, Hurricane Charley struck Southwest Florida in 2004 as a Category 4 hurricane, but produced a peak storm surge of just 6 to 7 feet.

Storm surge forecasts will continue to be included in hurricane advisories and statements issued by the National Hurricane Center and local National Weather Service forecast offices. Beginning with the 2009 hurricane season this information has been expressed in terms of height above ground level giving residents a better understanding of the potential for flooding at their location.

The decision to implement the Saffir-Simpson Hurricane Wind Scale was based, in part, on an assessment of the responses received during a 2009 public comment period. The descriptions of wind impacts in the new scale were updated with assistance from highly respected wind scientists from academia and industry.

"I applaud the NOAA decision to decouple storm surge predictions from the Saffir-Simpson scale," said Al Goodman, Floodplain Management Bureau director, Mississippi Emergency Management Agency. Goodman noted that while Hurricane Katrina hit the Gulf Coast with top winds of Category 3 strength, its expected and actual storm surge was associated with a higher Category of storm when ranked on the original Saffir-Simpson Scale.

Source: NOAA

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Since ancient times and probably long before people knew how to write and read, humans have been watching the moon; now you can do the same, but with a little help to make your moon watching sessions even better.

Other planets have scores of moons; Jupiter, Saturn, Uranus have many; even Mars ahs two but sadly one of them will get destroyed in a few centuries due to gravitational tides. But ours is special. The moon has accompanied us for thousands of years and it is really hard to believe that it is actually changing: It is known for a fact that the moon is going farther from the Earth, at a rate of approximately three centimetres each year. History also records some spectacular events that took place in the moon and were witnessed by people here on Earth without, in some cases, knowing exactly what was going on, like giant meteor hits on the moon's surface.

The moon was also one of the first objects of study of astrologists, astronomers and spiritual leaders. For many cultures, the moon is a god, or more often, a goddess. Coincidences of moon cycles - or not - with the human menstrual cycle provoked a lot of debates in past times that even had to do a lot with pretended justification for gender discrimination. Moon cycles were used for important decisions such as the departure of hunting or fishing expeditions, wars, peace treaties and so on. So there are additional, cultural dimensions to the moon other than astronomy, which, by the way, is no small or simple field of study at all.

Fortunately for the amateur astronomer or simply any moon watcher, our natural satellite is quite close to us and relatively easy to observe even with the naked eye. The question is not just to watch it, but to know what one is actually watching and in this regard, an atlas would be very handy and practical.

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Source: Andinia.com

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A new collection of selected Landsat earth images worldwide, Global Land Survey 2005 (GLS2005), is now available for free download to any user around the globe.

Under a long-term partnership, the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA) periodically select and process thousands of the best-available Landsat satellite images, or "scenes," into a Global Land Survey, recording baseline conditions across the Earth's land surface such as forest cover, urban sprawl, cropland areas, glacier size, regional snow cover, drought status, wildfire scars, and coastal features. User demand for GLS data has been increasing steadily, with many scientists claiming these data sets are invaluable for global-change and climate-change research.

Nearly 10,000 satellite images, each covering approximately 100 X 100 miles, are now available from the recently completed 2005 data set. Previous sets include GLS1975, GLS1990, and GLS2000. All GLS images can be previewed and downloaded for free at either of two USGS web sites: Glovis or Earth Explorer.

The earliest GLS data sets, GLS1975 and GLS1990, were drawn from U.S. and international partner receiving-station archives of images captured by earlier Landsat satellites that could image regions all over the world but did not have the capacity to record full global coverage and return it to the U.S. archive. Due to this limitation, plus persistent cloud cover in some parts of the world, these GLS data sets include images from years on either side of their nominal date.

Landsat 7, launched in 1999, was the first satellite capable of recording and returning entire seasonal data collections on a global scale, which enabled creation of the GLS2000 data set from a single satellite over a relatively short time period. However, due to a technical malfunction in 2003, wherein 22% of the pixels in each Landsat 7 image are lost, plus the availability of excellent data from two other Landsat sensors, the GLS2005 collection includes: Landsat 7 scenes with missing pixels filled in from images captured over the same site shortly before or after the selected GLS scene; Landsat 5 images of some areas; and images of islands and reefs captured by the Landsat-prototype sensor onboard NASA's Earth Observing 1 (EO-1) satellite.

Fuller descriptions of the GLS data sets can be found at the web sites mentioned above. Other questions or comments can be directed to custserv@usgs.gov.

Source: USGS

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