One of the strongest La Niña events in the past half century

[neufer]

TRMM rainfall anomalies: Nov. 23 to Dec. 23, 2010.

---

Australia Greens After Record Rains

---

One of the strongest La Niña events in the past half century

---

<<Peruvian fisherman named El Niño (Spanish for “the boy child”) after the Christ child because the climate phenomenon usually shows up around Christmastime. But its counterpart, La Niña, is the gift giver, bringing cold, nutrient-rich water to the equatorial Pacific off South America. Those nutrients are a boon to marine life, supporting a larger fish population and increasing the fishermen's catch. Fishermen might expect a good year ahead, as a strong La Niña is now dominating the Pacific Ocean.

“This is one of the strongest La Niña events in the past half century, and will likely persist into the northern hemisphere summer,” says Bill Patzert, an oceanographer and climatologist at NASA’s Jet Propulsion Laboratory. “Climatic impacts include heavy rains and flooding, which has damaged crops and flooded mines in Australia and Asia. It also has resulted in flooding in northern South America and drought conditions in Argentina. This powerful little lady is spreading her curses and blessings across the planet. She’s the real deal.”

La Niña’s cold water signal is strong in the top two images. The left image shows ocean surface temperatures on December 15, 2010, as measured by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA’s Aqua satellite. In December 2010, sea surface temperatures were colder than average across the equatorial Pacific.

The right image depicts the heat content of the ocean surface between December 14 and 16, 2010, as observed by the U.S.-French Ocean Surface Topography Mission (OSTM)/Jason-2 satellite. Water expands as it warms, so warmer water has a higher surface elevation than cooler water. The blue valley streaking across the middle of the sea surface height image is the signature of La Niña. The intensity of the cold water and the depth and extent of the valley point to an intense event.

Like El Niño, La Niña comes from changes in both the ocean and the atmosphere. High pressure usually dominates the atmosphere over the eastern Pacific, while low pressure tends to reign in the west. The pressure difference creates the trade winds, which blow surface water across the equatorial Pacific to a pool of warm water in the west. Cooler deep water wells up to replace the surface water. During La Niña events, the pressure difference and the resulting trade winds are stronger. The more intense winds push more water west, where it builds up north of Australia. Meanwhile, more cold water wells up in the central and eastern Pacific.

La Niña occurs only when both the ocean and the atmosphere change together, and in 2010, they have, says oceanographer David Adamec of NASA’s Goddard Space Flight Center. The unusual ocean temperatures and imbalance in air pressures alter weather patterns across the world.

The far right images shows some of the unusual weather La Niña brought in December 2010, as observed by the Tropical Rainfall Measuring Mission (TRMM) between November 23 and December 23, 2010. The image shows rainfall totals compared to average rainfall for the period, with above-average rain in blue and less-than-average rainfall in brown. “Weather effects are strong in the western Pacific,” says Adamec. “Australia is flooding in many areas.” La Niña rainfall patterns are also evident in the stark horseshoe-shaped region of unusually dry weather in the central Pacific.

La Niña typically affects weather patterns in North America beginning in January. “For ‘normal’ effects in the U.S., look for cold in the Upper Plains, dry and warm weather in California, dry weather in the southeast, especially Florida, and unusually soggy weather in the Northwest,“ says Adamec. Because such a wide swath of the Pacific is cold, La Niña tends to keep a lid on global temperatures. 2010, however, was still shaping up to be the hottest year on record in spite of La Niña, according to scientists from NASA Goddard Institute for Space Studies.>>

[geckzilla]

Estivating frogs of Australia approve.

[neufer]

Estivating frogs of Australia approve.

And God knows how big the geckos are growing!

<<Estivation or aestivation (from Latin aestas, summer), also known as "summer sleep", is a state of animal dormancy somewhat similar to hibernation. It takes place during times of heat and dryness, the hot dry season, which is often but not necessarily the summer months.

Invertebrate and vertebrate animals are known to enter this state to avoid damage from high temperatures and the risk of desiccation. Both terrestrial and aquatic animals undergo estivation.

The Water-holding Frog has an estivation cycle. It buries itself in sandy ground in a secreted, water-tight, mucus cocoon during periods of hot, dry weather. Australian Aborigines discovered a means to take advantage of this by digging up one of these frogs and gently squeezing it, causing the frog to release some of the fresh water it stores for itself in its bladder and skin pockets. This water can be drunk by the aborigine, who then releases the frog.

Introduced Theba pisana snails aestivating on a row of fence posts in Kadina, South Australia

---

Gastropoda: Some air-breathing land snails, including species in the genera Helix, Cernuella, Helicella and Otala, commonly estivate during periods of heat. Some species move into shaded vegetation or rubble. Others climb up tall plants, including bushes and trees, and will also climb man-made structures such as posts, fences, etc., to escape intense ground heat.

The habit of climbing vegetation to estivate has caused more than one introduced snail species to be declared an agricultural nuisance.

To seal the opening to their shell to prevent water loss, pulmonate land snails secrete a membrane of dried mucus called an epiphragm. In certain species, such as Helix pomatia, this barrier is reinforced with calcium carbonate, and thus it superficially resembles an operculum, except that it has a tiny hole to allow some oxygen exchange.

Insecta: Lady beetles (Coccinellidae) have been reported to estivate.

Non-mammalian animals that estivate include North American desert tortoises, crocodiles, salamander. Some amphibians (e.g. the cane toad and greater siren) estivate during the hot dry season by moving underground where it is cooler and more humid. The California red-legged frog may estivate to conserve energy when its food and water supply is low.

Until recently no primate, and no tropical mammal, was known to estivate. However, animal physiologist Kathrin Dausmann of Philipps University of Marburg, Germany, and coworkers presented evidence in the 24 June 2004 edition of Nature that the Malagasy fat-tailed dwarf lemur hibernates or estivates in a small cricket hollow for seven months of the year.>>

[neufer]

Click to play embedded YouTube video.

Click to play embedded YouTube video.

[neufer]

Click to view full size image 1 or image 2

<<Rivers in Australia’s Fitzroy Basin were swollen when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured the top image on January 4, 2011. The lower image, taken on December 14, 2010, shows the basin before the flooding started. The contrast between the two images indicates the severity of the flooding.

Both images were made with true color and infrared light, in a combination that highlights the presence of water on the ground. Water is usually black in this type of image, but the rivers here are tainted blue by thick sediment. The most extreme flooding occurs where the Mackenzie and Dawson rivers flow together to form the Fitzroy River.

Damaging floods hit the city of Rockhampton, the pale tan area that spans the Fitzroy. The river’s straight, well-defined channel through the city indicates some measure of flood control. North of the city, however, the river burst its bank and surrounded Rockhampton on the northwest. Similar flooding appears to be happening south of the city, but clouds (turquoise and white) obscure the view. As of January 5, the swollen river had closed the airport and a highway south of the city, and forced about 500 people to evacuate flooded neighborhoods, reported the Australian Broadcasting Corporation News.

According to the Australian Bureau of Meteorology, the Fitzroy River reached a peak of 9.2 meters in the city of Rockhampton on January 4, and maintained that level through January 5. The river is considered flooded when it reaches 7 meters. Forecasters expected the river to remain at 9.2 meters through January 6, and above the “major flood” level of 8.5 meters for another week. The floods are part of a larger event in Queensland, where the Australian Bureau of Meteorology had issued flood warnings for eight rivers. Floods throughout Queensland affected more than 200,000 people in 40 communities. Unusually heavy La Niña rains caused the floods, but they also allowed the country to green up after a multi-year drought.>>

[neufer]

Rockhampton, January 7, 2011

---

<<Though water levels had started to subside, the Australian city of Rockhampton was still inundated when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite took this image on January 7, 2011. The image includes both thermal-infrared and visible light to increase the contrast between muddy floodwater and brown earth. Reflective surfaces on buildings make the city shine white against a background of plant-covered land (which shows up as red). Sediment-loaded water is brown, while clearer water is black. Brown water covers rectangular blocks, particularly in southern Rockhampton. Tiny white flecks within the flooded area are buildings. Approximately 300 homes are believed to be flooded, reported the Australia Broadcasting Corporation.

The river has isolated Rockhampton both by land and air. The airport is flooded, with one runway dry and the other underwater. Airport buildings appear to be surrounded by the flood. The Bruce Highway leaving the city to the south is also under water. The Fitzroy River was at 30 feet on Friday, January 7, (7 feet above flood stage). The river peaked at 30.2 feet on Wednesday, and forecasters expect the river to recede very slowly over the next week.>>

[neufer]

Click to view full size image

[youtube]http://www.youtube.com/watch?v=P1JxXzVM ... r_embedded[/youtube]

[neufer]

Heavy Rains in Queensland

---

<<Torrential rain pounded southeast Queensland, Australia, on January 10, 2011, bringing devastating flash floods to several communities just west of Brisbane. This image, made from the Multi-Satellite Precipitation Analysis (MPA) based on data from the Tropical Rainfall Measuring Mission (TRMM), shows the intense rain on January 10.

The storm was relatively concentrated, with the highest rainfall west and northwest of Brisbane. In the darkest blue regions, the TRMM MPA recorded rainfall totals greater than 200 millimeters (8 inches) for the day. Weather stations on the ground reported similar totals.

The rain fell on already saturated ground, said the Australian Bureau of Meteorology. With nowhere to go, the water formed intense flash floods that ripped through the Lockyer Valley, killing ten people and leaving 78 missing, according to news reports. The water drained east, pushing several rivers past major flood stage. Queensland’s largest city and capital, Brisbane, and the nearby city of Ipswich, expected the floods to affect some 45,000 homes by January 12, said Brisbane’s Courier Mail.

The storm continued a trend of rainy weather linked to La Niña. According to the Australian Bureau of Meteorology, Queensland had the wettest December on record in 2010, while the continent as a whole experienced its third wettest year in 2010. The extreme rain triggered widespread flooding across Queensland and New South Wales in December and January.>>