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Hurricane Season 2008: Charlotte (South Pacific Ocean)
01.13.09
 
Jan. 13, 2009

NASA Satellites See Flooded North Queensland, Australia - Charlotte Adds Rain

AIRS visible image of Charlotte on Jan. 13, 2009> Larger image
Credit: NASA JPL
Tropical Cyclone Charlotte's rains have added to an already serious episode of flooding in far north Queensland, Australia. Charlotte's rains in combination with a 3 meter (9.8 foot) "king tide" contributed to waist-deep waters in the region. A "kings tide" is an Australian term that means any high tide well above average height.

NASA's Aqua satellite captured this visible satellite image of Charlotte's clouds over the area on Jan. 12 at 4:11 UTC (Jan. 13 at 3:27 a.m. local time, Queensland), while NASA's Tropical Rainfall Measuring Mission satellite has measured the intense rainfall happening there since late December.

According to the Australian "Weekly Times Now" on-line news on Jan. 13 some towns are isolated by severe flooding and highways are under water. During the early morning hours (local time, Queensland) on Tuesday, Jan. 13, thousands of people were standing by to evacuate. The towns of Cairns, Port Douglas, Mossman and Innisfail recorded between 200mm and 400mm (7.8 to 15.7 inches) of rainfall on January 12. Cape Tribulation recorded 436mm (17.17 inches) on Sunday, Jan. 10, its highest January daily total in 28 years. Forecasters warn that coming monsoon rains are likely to flood a 500km (310 mile) stretch of coastline from Mossman to the Burdekin in the next few days.

Cyclone Charlotte weakened into a low on Jan. 11 over the southern path of Cape York.

TMPA rainfall totals are shown here for the 2 week period from December 24, 2008 to January 7, 2009 for Australia and the surrounding region.> Larger image
Credit: Hal Pierce, SSAI/NASA
NASA's TRMM Satellite Sees Heavy Rains, Flooding in Northern Australia

Over the past two weeks, torrential rains have brought both drought relief as well as severe flooding to parts of Queensland and the Northern Territory in northern Australia. The wet weather was due primarily to the start of the monsoon, a seasonal phenomenon wherein an area of low pressure forms over a large land mass, in this case the Australian continent, during local summer.

Because of the large heat capacity of water, land heats up much faster than water. This forces air to rise over the hotter land surface, which induces low pressure to form at the surface. The low pressure in turn then draws moist air in from the surrounding ocean, becoming a focus for shower and rain activity.

Armed with an array of active and passive sensors, the primary objective of the Tropical Rainfall Measuring Mission satellite (better known as TRMM) is to measure rainfall from space. For increased coverage, 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. monitors rainfall over the global Tropics.

TMPA rainfall totals are shown here for the 2-week period from December 24, 2008 to January 7, 2009 for Australia and the surrounding region. The most prominent feature is a northwest-southeast band of very heavy rain that lies just inland from the coast across central northern Australia. The band extends from the western edge of the Northern Territory in the west to the base of the York Peninsula in the east. Rainfall totals within this band are regularly in excess of 300 mm (~12 inches, shown in orange) with embedded areas of even higher amounts on the order of 400 mm (~16 inches, shown in red).

The last image shows TMPA rainfall anomalies for this same 2-week period in relation to the 10-year average for the same portion of the seasonal cycle.> Larger image
Image Credit: Hal Pierce, SSAI/NASA
In addition to the monsoon, there is another key phenomenon at work: La Niña, the counterpart to El Niño. Instead of above normal ocean temperatures in the central and eastern Pacific and below normal values in the western Pacific, La Niña brings the opposite. This results in enhanced rainfall over the western Pacific, Maritime Continent, and northern and eastern Australia as enhanced trade winds pile up even warmer waters in the West Pacific region.

The last image shows TMPA rainfall anomalies for this same 2-week period in relation to the 10-year average for the same portion of the seasonal cycle. Above average rainfall (shown in green and blue) extends from northern and eastern Australia northward towards the Maritime Continent. This pattern is consistent with the broad-scale rainfall signature for La Niña. The strong positive rain anomalies (shown in bright blue) indicate that this rain event is rather significant for this time of year.

For more information about NASA's Tropical Rainfall Measuring Mission satellite, visit: > TRMM Web site.

Text credit: Steve Lang (Aqua section: Rob Gutro)/SSAI / Goddard Space Flight Center


Jan. 12, 2009

Australia's Charlotte Makes a Brief, Yet Dramatic Appearance

AIRS infrared image of Tropical Cyclone Charlotte from Jan. 12, 2009> Larger image
Credit: NASA JPL/ Ed Olsen
Tropical Cyclone Charlotte formed in the early morning hour near the north central Australian coast on Sunday, January 11, about 37 miles north-northeast of Mornington Island. By Monday the 12th she had made landfall and was downgraded to a tropical low pressure area, while bringing heavy rain and winds to parts of north Queensland.

Early on the 11th after she formed, Charlotte crossed over the "top end" of Northern Territory which is the peninsula of the region. The Northern Territory surrounds Darwin and stretches east to the Arnhem Land, south to Kakadu and north to the Tiwi Islands.

Later on the 11th at 21:00 Zulu Time (4 p.m. EST), Charlotte she continued to track east and was about 90 miles east of Mornington Island, Australia. That's near 16.6 degrees south latitude and 141.4 east longitude. She then moved inland into Far North Queensland. Charlotte was the first cyclone in Queensland of the season, and she made land about 4 a.m. (local time, Australia) near the mouth of the Gilbert River. She's forecast to curve south then southwest into the outback part of Queensland and dissipate sometime on Jan. 13.

Just before Charlotte's center made landfall in the Gulf Country area of Far North Queensland, the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured Charlotte's cloud temperatures. AIRS produced this infrared image on Jan. 11 at 11:05 a.m. EST (16:05 UTC). Charlotte is depicted in this AIRS image as the round area of clouds in the center of this image.

The infrared image shows the frigid cloud top temperatures, giving forecasters a clue to the storm's strength. The coldest temperatures (and highest cloud tops) shown in purple are as cold as 220 degrees Kelvin or minus 63 degrees Fahrenheit (F) or colder. The lower clouds are depicted as the blue areas, which are around 240 degrees Kelvin, or minus 27F.

At that time, Charlotte's maximum sustained winds were near 35 knots (40 mph) with higher gusts. She was moving east near 6 knots (7 mph), but was already turning to the east-southeast.

Text credit: Rob Gutro/Goddard Space Flight Center