2.23.2006

DD3132

See if this dream has come true yet | Submit information for this dream

Expect a major change in the jets streams that circle the world this year, will dramatically change weather patterns.

3.9.2006

---

NASA Goes Back in Time to Find the Sources of the 1930s Dust Bowl

In 1931, the middle of the U.S. was hit by a long-term drought that brought fear in handfuls of dust. Rain stopped falling from the skies over the Great Plains, and crops died. Then, the "black blizzards" began, as dust from over-plowed and over-grazed fields blew across the land. By late spring of 1934, the Dust Bowl drought was named the worst in our country's history, severely drying out 27 states and three-fourths of the country. By the time it ended in 1939, the U.S. economy had been devastated.

While droughts like this are rare, it is important to understand why they occur. Now, a team of scientists from NASA Goddard Space Flight Center, headed by Siegfried Schubert, have an explanation. In a study published in the March 19th issue of Science, Schubert and colleagues used a NASA computer model developed with modern-era information from satellites to look back and reconstruct the climate of the past 100 years.

The study found cooler than normal tropical Pacific Ocean surface temperatures (blues in image and animation below) combined with warmer tropical Atlantic Ocean temperatures (red-orange in image and animation below) to create conditions in the atmosphere that turned America's breadbasket into a dust bowl for most of the 1930s.

These changes in sea surface temperatures contributed to a weakened low-level jet stream and changed its course. The jet stream, a ribbon of fast moving air near the Earth's surface, normally flows westward over the Gulf of Mexico and then turns northward pulling up moisture and dumping rain onto the Great Plains. As the low level jet stream weakened, it traveled farther south than normal. The Great Plains dried up and dust storms formed. This process is shown in the animation on the left.

"The 1930s drought was the major climatic event in the nation's history," Schubert said. "Just beginning to understand what occurred is really critical to understanding future droughts and the links to global climate change issues we're experiencing today," he said.

By discovering the causes behind U.S. droughts, especially severe episodes like the Plains' dry spell, scientists may recognize and possibly foresee future patterns that could create similar conditions. For example, La Ni񡳠are marked by cooler than normal tropical Pacific Ocean surface water temperatures, which impact weather globally, and also create dry conditions over the Great Plains.

The research sheds light on how tropical sea surface temperatures can have a remote response and control over weather and climate. The study also helps us understand droughts throughout the 20th century. Analysis of other major U.S. droughts of the 1900s suggests a cool tropical Pacific was a common factor. Schubert said simulating major events like the 1930s drought provides an excellent test for computer models. While the study finds no indication of a similar Great Plains drought in the near future, it is vital to continue studies relating to climate change.

 

• NASA looks at the 1930s

 

AccuWeather.com meteorologists are warning that oceanic conditions similar to those that triggered the ruinous "Dust Bowl" drought again appear to be in place. The exceptionally warm Atlantic waters that played a major role in the record-breaking 2005 hurricane season, coupled with cooler-than-normal Pacific waters, are weakening and changing the course of a low-level jet stream that normally channels moisture into the Great Plains. Effects are starting to be felt in "America's breadbasket," as the southern Great Plains region is already suffering from higher temperatures and a prolonged lack of precipitation.

Why could a new Dust Bowl drought occur?
The low-level jet stream-a fast-moving current of winds close to the Earth's surface-travels from east to west across the Atlantic, then typically curves northward as it crosses the Gulf of Mexico, bringing moisture to the Great Plains. Abnormal sea-surface temperatures have caused this low-level jet stream to continue westward and to weaken, which is preventing much-needed moisture from reaching the agriculturally critical region. The shift in the jet stream is also allowing a southerly flow from Mexico to bring much drier air northward into the Plains.

Besides dramatically reducing precipitation for the region, the changes brought about by the abnormal sea-surface temperatures will also result in higher surface temperatures in the Plains. "When surfaces are wet, energy from solar radiation both evaporates moisture and heats the ground," said AccuWeather.com Chief Meteorologist Elliot Abrams. "When no moisture is present, all that energy is channeled toward heating the ground, and the warmer ground heats the lower atmosphere. The combination of low moisture and higher temperatures would be a crippling one-two punch for the Great Plains should these conditions persist, much like what occurred during the Dust Bowl drought."


 

dream diary navigation

For the lasted information on my dreams, please visit my Dream Forum here, or see below for the very latest posts.

all dreams - dreams this year - this month - this week - last night - top 10 - correct - thumbnails - dream forum - dream cures - dreams about you -  tell-a-friend

Additional Site Information and Links

Click below to view my nightly Missing Persons TV Show and Dream Talk with Brian Ladd and Debra Brink - Click here to access my Dream Forum now.