Meteorologists investigate Airborne jet streams bringing both floods and drought relief

A satellite image showing water-vapour concentration reveals an atmospheric river (yellow) streaming northeast across the Pacific Ocean.

Californians call it the Pineapple Express: a weather pattern that zips across the Pacific Ocean from Hawaii, delivering not baskets of tropical fruit, but buckets of rain and snow.

In meteorological terms, the Pineapple Express is an atmospheric river, a narrow band of air that carries huge amounts of moisture.

For the next six weeks, meteorologists will be plying the eastern Pacific by air and sea, in the hope of catching several atmospheric rivers barrelling towards the coast.

It is the biggest push yet to understand these phenomena, which have received serious scientific attention only in the past decade.

Atmospheric rivers get their start over warm tropical waters; they then flow eastwards and towards the poles a kilometre or two above the ocean surface.

They may stretch for thousands of kilometres, but are only a few hundred kilometres wide. When they hit land, they start to drop their moisture in torrential downpours or blizzards.

“When we have too many atmospheric rivers, floods can occur, and when we don’t have enough we gradually fall into drought,” says Marty Ralph, a meteorologist at the Scripps Institution of Oceanography in La Jolla, California, and a leader of the field campaign.

In Europe, atmospheric rivers affect mostly the western part of the continent, but they can be felt as far inland as Poland.

In North America, the entire west coast is affected, and parts of the central and eastern United States occasionally feel the effects of atmospheric rivers that develop over the Gulf of Mexico.

The moisture is often welcome, bringing up to half of the year’s water supply in affected areas1.

A 2013 study found that as many as three-quarters of all droughts in the Pacific Northwest between 1950 and 2010 had been brought to an end by atmospheric-river storms2.

California has been stricken by drought for years (Nature 512, 121–122; 2014), but last month, an atmospheric river dropped enough rain to erase one-third of the water deficit of one major reservoir in just two days.

Climate change may bring stronger and more frequent atmospheric rivers, because the warmer the atmosphere is, the more water it can hold, says David Lavers, a meteorologist at Scripps who is not involved in the project.

“The more you know about how the atmosphere behaves,” he says, “the better position you’re in to prepare for extreme events.”

Read the full article on Nature website - Nature 517, 424–425 (22 January 2015) doi:10.1038/517424a

Texas drought exposes doomed NASA Shuttle Columbia debris

The prolonged drought in Texas has revealed what NASA says is a tank from the space shuttle Columbia, which broke apart over east Texas as it re-entered the atmosphere in 2003.

Greg Sowell, a police sergeant in the city of Nacogdoches, which is located about 160 miles (250 kilometers) northeast of Houston, said the waters of Lake Nacogdoches, which are falling due to the record drought which has gripped the state, revealed an unexpected object.

"We found a large, about four-foot-diameter, round, what appears to be a tank of some sort," Sowell said Tuesday. "We have reason to believe this may be a part of the Columbia space shuttle."

The police department sent photos of the object to NASA for review, and experts at the space agency confirmed that the object was a power reactant storage and distribution tank. Such tanks are used aboard the shuttle to store cryogenic fuel for electrical power during flight.

Lisa Malone, a spokeswoman at NASA's Kennedy Space Center in Florida, told msnbc.com that Columbia carried 18 of the tanks for its 16-day mission.

Columbia broke apart upon re-entry into the atmosphere on Feb. 1, 2003, killing the seven crew members on board. Debris from the spacecraft, which disintegrated over a wide area of east Texas, has been found in about 2,000 locations across eastern Texas and western Louisiana, including in Nacogdoches.

"Due to the drought, Lake Nacogdoches is at an approximately 9-foot low," Sowell said. "There has been an unusually large area of the lake which is normally underwater which has been exposed."

Sowell noted that space shuttle debris is considered government property, and that tampering with such objects is a criminal offense.

Malone said NASA and local authorities were working out a plan for recovering the tank and bringing it to Kennedy Space Center's Vehicle Assembly Building, where previously recovered pieces from Columbia — including other fuel-cell tanks — are being stored under climate-controlled conditions.

ESA SMOS: Horn of Africa drought visible from space

The animation, derived from SMOS satellite data, shows soil moisture in the Horn of Africa from April to mid-July 2011.

The orange and yellow colouring depicts little to no moisture, while green and blue depict higher levels of soil moisture.

Credits: CESBIO/ESA

ESA: Horn of Africa drought seen from space - images

Kenya Drought: The true cost of Global Catastrophe

Farmers in drought-stricken Kenya are cutting their losses by selling their dying livestock for meat at places like the Kenya Meat Commission.