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Hurricane Season 2009: Ellie (Southern Pacific)
02.04.09
 
Feb. 04, 2009

Ellie Now Off-shore, May Regenerate and a Second Low Being Watched

Cyclone Ellie's rainfall rates Credit: NASA/SSAI, Hal Pierce
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On Feb. 4, 2009 the residents of northern Queensland, Australia were thinking they were out of the woods from more flooding and heavy rainfall as former Cyclone Ellie's center had moved off-shore. Elllie had moved into the southeast Gulf of Carpentaria, where forecasters are now keeping a close eye on her for possible regeneration and a second landfall.

Meanwhile there's another low pressure system that may add to the flooding in the region. That low is located in the Coral Sea near the town of Cairns, and forecasters think that it may turn into a cyclone as soon as Friday, Feb. 6.

Designed to measure rainfall from space, the Tropical Rainfall Measuring Mission satellite (better known as TRMM) has been in service for over 10 years now and continues to provide valuable images and information on tropical cyclones around the Tropics using a combination of passive microwave and active radar sensors. TRMM captured this image of Cyclone Ellie at 05:25 UTC (3:25 pm AEST) February 2, 2009, about 15 hours after it made landfall. The image shows the horizontal distribution of rain rates as seen from the low-earth orbit perspective of the TRMM satellite. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), the first precipitation radar in space, and those in the outer part of the swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS).

Map of Cyclone Ellie over Australia Credit: NASA/SSAI, Hal Pierce
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As tropical cyclones quickly weaken over land, it is not surprising that Ellie, which was a weak system to begin with, appears only loosely organized. There is no evidence of an eye or eyewall or intense convection near the center; however, large bands (or arcs) of light to moderate intensity rain (blue and green areas, respectively) spiral inwards towards the center in a clockwise fashion, indicating the presence of a broad low-pressure circulation associated with the remnants of Ellie. In addition to the rainshowers directly linked with storm, this circulation can pump additional moist air inland over Queensland.

TRMM can be used to calibrate rainfall estimates from other additional satellites. The TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center, Greenbelt, Md. is used to monitor rainfall over the global Tropics. TMPA rainfall totals are shown here for the period January 27 to February 3, 2009. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

The storm has caused widespread flooding across the region because rainfall from tropical cyclones is heavily dependent on how long they persist over a given area rather than their intensity, and Ellie has been a slow- moving system.

Text credit: Steve Lang / Rob Gutro/NASA Goddard Space Flight Center / SSAI


Feb. 03, 2009

NASA's TRMM Rainfall Map Shows Cyclone Ellie's Serious Flooding Rains

TRMM image of Tropical Cyclone Ellie> Larger image
Credit: NASA
The North Queensland region of Australia was recently inundated with heavy rains from Tropical Cyclone Ellie, and a NASA satellite-generated rainfall map captured the extent of the deluge showing rainfall from 4 to 20 inches.

This image from NASA's Tropical Rainfall Measuring Mission (TRMM) satellite provides rainfall data from its perch in orbit above the Earth. TRMM has been called a "rain gauge in space" and can provide accurate measurements of rainfall in tropical and sub-tropical areas around the world.

TRMM can be used to calibrate rainfall estimates from other additional satellites. The TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center, Greenbelt, Md. is used to monitor rainfall over the global Tropics. TMPA rainfall totals are shown here for the period January 27 to February 3, 2009. The Queensland region in northeastern Australia is the area with the point on the top right part of the continent. TRMM rainfall indicates that between 100-500 millimeters (mm) of rain (4-20 inches) of rain have recently fallen there. The yellow-green area on the rainfall map is around 100 mm, red is between 300-400 mm, while the purple indicates almost 500 mm of rainfall.

This product was developed in the Laboratory for Atmospheres of the NASA Goddard Space Flight Center, Greenbelt, Md. by the TRMM precipitation research team.

Global accumulation of rainfall map from TRMM > Larger image
This is a close-up view of the heavy rainfall from Tropical Cyclone Ellie on Feb. 3, 2009. The purple area indicates as much as 20 inches of rainfall. Credit: NASA

The Courier Mail Newspaper of Australia reported on Feb. 3 that the worst-hit area was Ingham, between Cairns and Townsville. There were at least 20 homes flooded and evacuated as the nearby Herbert River peaked at 12.2 meters (40 feet). That was its highest level in 20 years. Roads were flooded out, and water covered part of the runway at Ingham airport. North and south of the town of Ingham, the Bruce Highway is flooded, cutting it off to vehicles and making it only accessible by boat or helicopter.

The Australian Weather Bureau reported early on Feb. 3 that more than 400mm of rain had fallen in the area over two days, and the Environmental Protection Agency issued a warning for people in flooded areas to be wary of snakes and crocodiles.

Elsewhere, in the Gulf country, evacuation plans are in place if the nearby Norman River levels rise past 8 meters (26 feet). However, the Courier reports that homes are already flooded, and many cars are already submerged from floodwaters. It is estimated that thousands of square kilometers (hundreds of square miles) of cattle country are underwater now.

David Grant, from Australia's Tropical Cyclone Warning Centre, said 282mm (11.1 inches) of rain fell at Ingham, while Innisfail recorded 226mm (8.89 inches). Forecasters are expecting Tropical Depression Ellie to continue raining on north Queensland for the next few days, adding to the flooding.

For more information about how TRMM looks at rainfall, visit NASA's TRMM website at: http://trmm.gsfc.nasa.gov/. TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Rob Gutro/NASA Goddard Space Flight Center


Feb. 02, 2009

AIRS image of Tropical Cyclone Ellie> Larger image
Credit: NASA/JPL
Ellie Forms Quickly, Hits Northeast Australia

Australia has been experiencing a heat wave, and now another tropical cyclone has formed and made a quick landfall in the Queensland region of the country. NASA's Aqua satellite not only captured the cold clouds of the storm, but also the scorching hot ground of the southern half of the continent from the heatwave.

Ellie, or Tropical Cyclone 12P, made landfall in northeastern Australia on Sunday, February 1 and weakened below tropical cyclone strength. The Queensland region of Australia is in the northeastern part of the country. Because she is forecast to recurve out to sea by Tuesday, forecasters are keeping a close eye on her for signs of regeneration. On Feb. 1 at 2100 UTC (4 p.m. EST), Ellie was 85 miles south of the town of Cairns, moving southwest near 7 knots (8 mph). Her maximum sustained winds were down to 30 knots (34 mph).

Ellie formed late on Saturday, January 31 offshore about 100 miles east of Cairns, Queensland, Australia, and began moving towards the Queensland coast. Her maximum sustained winds reached a peak speed of 40 knots (46 mph). Since her development, her winds have continued to weaken. Before her landfall, a cyclone warning from the Australian Government was in force for coastal and island communities from Cairns to Townsville.

NASA's AIRS Shows Icy Clouds and Scorching Earth The infrared imagery of the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite is used to identify the cloud temperatures in tropical cyclones. It captured this image of Ellie on Feb. 2 at 4:29 Zulu Time (Feb. 1 at 11:29 p.m. EST) after she made landfall.

The infrared image also shows a large temperature difference between the tops of the clouds in a tropical cyclone and the scorching hot land in southern Australia where the heatwave continues.

In the storm's clouds, the lowest temperatures (in purple) are associated with high, cold cloud tops. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F.

AIRS infrared signal doesn't penetrate through clouds, so where there are clear skies AIRS reads the infrared (heat) signal from the ocean and land surfaces, revealing warmer temperatures (colored in orange and red). The orange temperatures are 80F (300 degrees Kelvin) or greater (the darker they are, the warmer they are). The dark red temperatures are greater than 310 Kelvin, or greater than 99 degrees Fahrenheit!

AIRS generates infrared, microwave and visible images. The AIRS infrared data creates an accurate 3-D map of atmospheric temperature, water vapor and clouds, all of which are helpful to forecasters.

Text credit: Rob Gutro/NASA Goddard Space Flight Center