Monday, February 22, 2010

Stratospheric Water Vapor is a Global Warming Wild Card

A 10 percent drop in water vapor ten miles above Earth's surface has had a big impact on global warming, say researchers in a study published online January 28 in the journal Science. The findings might help explain why global surface temperatures have not risen as fast in the last ten years as they did in the 1980s and 1990s.

Observations from satellites and balloons show that stratospheric water vapor has had its ups and downs lately, increasing in the 1980s and 1990s, and then dropping after 2000. The authors show that these changes occurred precisely in a narrow altitude region of the stratosphere where they would have the biggest effects on climate.
Water vapor is a highly variable gas and has long been recognized as an important player in the cocktail of greenhouse gases- carbon dioxide, methane, halocarbons, nitrous oxide, and others- that affect climate.

"Current climate models do a remarkable job on water vapor near the surface. But this is different - it's a thin wedge of the upper atmosphere that packs a wallop from one decade to the next in a way we didn't expect," says Susan Solomon, NOAA senior scientist and first author of the study.

Since 2000, water vapor in the stratosphere decreased by about 10 percent. The reason for the recent decline in water vapor is unknown. The new study used calculations and models to show that the cooling from this change caused surface temperatures to increase about 25 percent more slowly than they would have otherwise, due only to the increases in carbon dioxide and other greenhouse gases.



An increase in stratospheric water vapor in the 1990s likely had the opposite effect of increasing the rate of warming observed during that time by about 30 percent, the authors found.

The stratosphere is a region of the atmosphere from about eight to 30 miles above the Earth's surface. Water vapor enters the stratosphere mainly as air rises in the tropics. Previous studies suggested that stratospheric water vapor might contribute significantly to climate change. The new study is the first to relate water vapor in the stratosphere to the specific variations in warming of the past few decades.

Thursday, February 11, 2010

Water Supply is Great Shape in Phoenix

You may have seen the 2008 water supply ratings recently reported by Sustain Lane. They did not give Phoenix a favorable rating for reliability of water supplies. They are mistaken.

Although we should use water wisely, Phoenix has ample water supplies for years to come:

  • Phoenix does not depend upon the rainfall that occurs in the Valley for its water. Over one hundred years, the City has developed multiple water sources to create a diversified water portfolio.
  • In recent years, water conservation efforts, efficient use of reclaimed water for non-potable use, extensive groundwater management, and aggressive leak detection have stretched our available water supplies.
  • The City conducts effective drought management planning that ensures reliable supplies.

In the last 20 years, Phoenix's per person usage of water has dropped 20 percent. Total water use in Phoenix is no higher today than ten years ago.

Phoenix has gone even further than the sustainability requirements of the State of Arizona. The city has reduced its groundwater use to a minimum and is planning for a sustainable yield, as well as its assured 100 year supply, under conditions of long-term drought and global climate change — not just under normal conditions. And, Phoenix recycles 90 percent of its wastewater, using it in agriculture, energy production, urban irrigation of golf courses and cemeteries, aquifer recharge and riparian wetland maintenance.

Water conservation is promoted as a lifestyle, asking customers to think about water every time they use it.

Through these efforts, Phoenix water supplies have kept pace with demand. The City continues to plan for future growth.

Tuesday, February 2, 2010

NASA Radar Captures its 1st Haiti Image

JPL’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) captured this false-color composite image of the city of Port-au-Prince, Haiti, and the surrounding region on Jan. 27, 2010. Port-au-Prince is visible near the center of the image. The large dark line running east-west near the city is the main airport. UAVSAR left NASA’s Dryden Flight Research Center in Edwards, Calif., Jan. 25, 2010, aboard a modified NASA Gulfstream III aircraft on a three-week campaign that will also take it to Central America.



For more info http://www.nasa.gov/topics/earth/features/haiti20100201.html