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Hurricane Season 2009: Kujira (Western Pacific Ocean)
05.07.09
 
May 7, 2009

AIRS image of Kurija's cold clouds as it becomes extratropical. AIRS image of Kurija's cold clouds as it becomes extratropical.
Credit: NASA JPL, Ed Olsen
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Kujira's Swan Song Plays as it Heads Northeast in Open Ocean

Typhoon Kujira's days are numbered. The U.S. Navy's Joint Typhoon Warning Center is the organization that forecasts tropical cyclones in the western Pacific, and they've just issued their last warning on Cyclone Kujira.

During the day on Thursday, May 7 the center of Kujira passed to the east of the island of Chichi Jima, Japan. At 0300 Zulu Time, or 11 p.m. EDT on May 6, Kujira was 150 nautical miles east-northeast of Iwo To (formely, Iwo Jima) near 27.2 north and 144.6 east. At that time it had sustained winds near 50 knots (57 mph) that were waning.

Forecasters at the Joint Typhoon Warning Center noticed that Kujira had "rapidly lost its vertical organization and is beginning to take on frontal characteristics, indicative of an extratropical system." By 15:00 Zulu Time (11 a.m. EDT) today, it completed the transition to an extra-tropical storm in the open waters of the western Pacific Ocean.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of Kujira on May 6 at 16:23 Zulu Time (12:23 p.m. EDT). The image, showing cold (purple and blue) temperatures in the clouds of the storm appear as a sideways crescent moon with tails of clouds going northeast and southwest.

The infrared image shows a large temperature differences between icy cloudtops and the warm ocean temperatures. In this image, the orange temperatures are 80F (300 degrees Kelvin) or warmer. 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.

What Does "Conversion to an Extratropical Storm" Mean?

A conversion to "extratropical" status means that the area of low pressure (Kurjia) loses its warm core and becomes a cold-core system. During the time it is becoming extratropical the cyclone's primary energy source changes from the release of latent heat from condensation (from thunderstorms near the storm's center) to baroclinic (temperature and air pressure) processes. When a cyclone becomes extratropical it will usually connect with nearby fronts and or troughs (extended areas of low pressure) consistent with a baroclinic (pressure) system. When that happens it appears the system grows larger while the core weakens.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



May 6, 2009

Killer Cyclone Kujira Passing Japanese Island of Iwo To

satellite image of Kujira Infrared image of Typhoon Kujira from NASA's AIRS instrument. Purple indicates coldest clouds and strongest thunderstorms. Credit: NASA JPL/Ed Olsen
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Kujira had deadly reputation before moving toward the Japanese island of Iwo To (formerly known as Iwo Jima), and fortunately it appears that it will stay to the island's east. Twenty-five deaths were reported in the eastern Philippines from floods and landslides when cyclone Kujira developed there earlier this week.

The center of Kujira is expected to remain about 115 miles east of Iwo To, bringing thunderstorms and winds only up to 22 mph on Thursday, May 7 during the day and nighttime. After it passes Iwo To, it will head toward the island of Chichi Jima, Japan. It will then progress on a northeasterly track, avoiding the Japan mainland. Kujira continues to move into battering wind shear and cooler waters and is expected to weaken as a result of them.

On May 6 at 1500 Zulu Time (11 a.m. EDT), Typhoon Kujira was packing maximum sustained winds near 97 mph (85 knots), making it a Category 2 typhoon on the Saffir-Simpson hurricane scale. It was located about 110 nautical miles south-southeast of Iwo To, Japan near 23.6 north and 142.4 east. It was moving 23 mph in a northeasterly direction while creating waves up to 23 feet high.

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 and caught Kujira on its northeasterly track.

The infrared image, taken on May 6 at 12:11 a.m. EDT (04:11 UTC) shows the cold cloud temperatures in Typhoon Kujira. There's a large temperature difference between typhoon's cloudtops and the warmer ocean waters. The lowest temperatures (in purple) are associated with high, cold cloud tops in Kujira. 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.

Because the AIRS infrared signal doesn't penetrate through clouds areas of clear skies show 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 Joint Typhoon Warning Center noted in their recent update "Environmental analysis indicates vertical wind shear (winds blowing at different heights in the atmosphere that can tear a storm apart) over the typhoon's track has increased to over 46 mph (40 knots) and sea surface temperatures, now below 75 F (24 C), continue to decrease as the system accelerates. "

Text credit: Rob Gutro, NASA's Goddard Space Flight Center



May 5, 2009

Image from TRMM that shows what would later become Kujira just after it had formed into a tropical depression Credit: NASA/SSAI, Hal Pierce
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Philippines Feel the Effects of Typhoon Kujira

Kujira became the first typhoon of the year in the northern West Pacific as it pulled away from the east-central Philippines early on the afternoon (local time) of May 4, 2009. The Philippines, which are frequently influenced by tropical cyclones, felt the effects of Kujira (known locally as "Dante") while it was still just a tropical storm.

A tropical depression formed from a stationary area of low pressure on the afternoon (local time) of May 1st near the southeastern tip of Luzon along the eastern side of the central Philippines. Later that same day the depression was upgraded to a minimal tropical storm and was named Kujira.

The Tropical Rainfall Measuring Mission satellite (commonly known as TRMM) has been providing valuable images and information on tropical cyclones around the tropics for over 11 years now since its launch back in November of 1997. Armed with a combination of passive microwave and active radar sensors, TRMM can provide unique images of tropical cyclones.

The first image from TRMM shows what would later become Kujira just after it had formed into a tropical depression. The image was taken at 6:28 UTC (2:28 pm local time) on May 2. It shows the horizontal pattern of rain intensity (top down view) within the depression. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), a unique space-borne precipitation radar, while those in the outer swath are from the TRMM Microwave Imager (TMI). These rain rates are overlaid on visible and infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS).

At the time of this image, the system was a new depression with sustained winds estimated at just 30 knots (35 mph) by the Joint Typhoon Warning Center. The center of circulation, located just to the south of Catanduanes Island, is apparent from the banding (curvature) in the rain pattern. Light to moderate rain (blue and green areas, respectively) with locally heavier rates (red areas, which are often associated with areas of deep convection) are located near and just to the east of the center over land. Despite its relatively weak intensity, the system was able to generate a substantial amount of rainfall due primarily to its slow movement.

Rainfall totals associated with Kujira are shown for the period April 27 to May 4, 2009 Rainfall totals associated with this system are shown for the period April 27 to May 4, 2009.
Credit: NASA/SSAI, Hal Pierce
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Besides its own estimates, TRMM can be used to calibrate rainfall estimates from other satellites for increased coverage. The TRMM-based, near-real time Multi-satellite Precipitation Analysis (TMPA) at the NASA Goddard Space Flight Center is used to monitor rainfall over the global Tropics. TMPA rainfall totals associated with this system are shown for the period April 27 to May 4, 2009.

The analysis shows extremely heavy amounts of rain on the order of 750 mm or more (~30 inches, shown by the lighter shade of brown) over southeastern Luzon and Catanduanes Island just to the east. Just over 12 hours after the previous TRMM snapshot of the depression was taken, a landslide in Sorsogon province in far southeastern Luzon killed 17 people when their houses were swept away in a village of Magallanes town. So far a total of 23 persons are reported to have died in the region on account of the storm, mainly due to flooding and landslides.


Kujira has a small, well-defined core with almost entirely of a complete eyewall containing moderate to intense rain Kujira has a small, well-defined core with almost entirely of a complete eyewall containing moderate to intense rain.
Credit: NASA/SSAI, Hal Pierce
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On Sunday May 3rd, Kujira finally began to move off to the northeast away from the islands and into the northern Philippine Sea. In the process, it also gained strength. This last image from TRMM was taken at 20:25 UTC on the 3rd of May (4:25 am, May 4 local time) as it was moving northeast away from the Philippines; at that time it was a strong tropical storm with sustained winds estimated at 55 knots (~63 mph). In this image, Kujira has a small but well-defined core made up almost entirely of a complete eyewall containing moderate to intense rain (continuous circular area of green and red, respectively). Kujira would go on to become a strong Category 3 typhoon with sustained winds estimated at 100 knots (115 mph) by the following afternoon. The storm is expected to strengthen slightly before weakening in the northwest Pacific well south of Japan.

On May 5 at 0900 Zulu Time (5 a.m. EDT), Kujira was located about 555 miles southwest of Iwo To, Japan. That's near 18.4 degrees north latitude and 134.0 degrees east longitude. Kujira had sustained winds near 105 knots (120 mph) and was moving east-northeast near 15 knots (17 mph).

TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Steve Lang, SSAI/Goddard Space Flight Center


May 4, 2009

Infrared image of Kujira Credit: NASA/JPL, Ed Olsen
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Tropical Cyclone Kurija Bolts Out of the Philippines and Intensifies

Weekends seem to breed tropical cyclones, and this past weekend was no different. Tropical Cyclone Kurija developed near the Philippines, and Tropical Storm Chan-hom formed south of Vietnam.

Kurija was a tropical storm with maximum sustained winds near 55 knots (63 mph) over the weekend, but has now reached cyclone strength while bolting out of the Philippines.

On Sunday, May 3, Kurija was tracking through the Philippines, where the storm was also known as "Dante," and warnings were posted for the Camarines Norte and Sur, Albay, Masbate, Burias Island, Polillo Island and Southern Quezon. All of those warnings were dropped on Monday, May 4 as Kurija continued to move in a northeasterly direction at 15 mph (13 knots) out of the area.

Residents in the Philippines are relieved that Kurija didn't strengthen to its current strength before it departed the area. On Monday, May 4 at 1200 Zulu Time (8 a.m. EDT), Kurija had reached Category Three status on the Saffir-Simpson Scale with maximum sustained winds near 100 knots (115 mph) and higher gusts. The storm is creating waves as high as 15 feet.

Kurija was located near 16.8 degrees north and 129.6 degrees east, or about 585 nautical miles south of Okinawa, Japan. Forecasters believe that Kurija will track parallel to the main island of Japan and remain at sea over the next several days.

NASA's Aqua satellite flew over the storm on May 4, at 12:23 a.m. EDT, and the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite captured an infrared image of the eastern side of the storm. The rectangle with the orange, yellow, purple and blue is the data from the satellite as it flew overhead. Everything outside of that rectangle wasn't under the satellite's flight path.

The AIRS infrared image shows the temperature of Kujira's cloud tops and the surface of the Earth (where there are no clouds). The coldest cloud temperatures are in purple (where the strongest convection is occurring). Those areas in purple have some of the strongest thunderstorms. The second coolest temperatures are in blue, which make up the clouds outside of the center of circulation. The warmer temperatures of the ocean and land are shown orange and red.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center