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Hurricane Season 2007: Krosa (Western Pacific)
10.04.07
 
Tropical Depression Krosa Dissipating Off the Coast of China

Satellite image of Krosa
Click image for enlargement.

Once a mighty "Super Typhoon" with sustained winds near 149 mph, three days later on Oct. 8, Krosa weakened to a tropical depression. Krosa is the Cambodian word for crane.

The last bulletin on Krosa was issued by the Joint Typhoon Warning Center on Monday, Oct. 8 at 18:00 UTC (2:00 p.m. EDT) when Krosa's center was located near 29.7 degrees north latitude and 123.0 degrees east longitude, or approximately 120 nautical miles southeast of Shanghai, China.

At that time, Krosa's sustained winds were down to 25 knots (28 mph) with gusts to 35 knots (40 mph), and it was moving east-northeast near 10 knots (11 mph). Minimum central pressure was 1009 millibars. Krosa is forecast to continue tracking east-northeastward and is forecast to dissipate as a tropical system but is expected to remain a weak extra-tropical low in the East China Sea.

The storm took a jog to the southwest just as it hit Taiwan, so that the eye passed south of Taipei. This infrared image from Oct 7 at 5:05 UTC (1:05 a.m. EDT), when peak sustained winds were near 45 knots (51 mph), was created by data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite. At this time, Krosa was on the coastline of China, between the cities of Fuzhou and Ningbo.

The Xinhua news agency reported that more than 1.4 million people were evacuated from the China's southeast coast. Krosa hit the Zhejiang and Fujian provinces on Sunday, Oct. 7, which was a national holiday in China.

Satellite image of Krosa
Click image for enlargement.

This AIRS image from Oct. 5 depicts Krosa when it was a Super Typhoon, and the eye is even visible (in yellow).

These AIRS images show the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the tops of Tropical Storm Krosa. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). This infrared image shows large areas of strong convection surrounding the core of the storm (in purple), particularly seen in Tropical Storm Krosa.

NASA's CloudSat Gives a Clear Look at Krosa's Clouds from Different Angles

Satellite image of Krosa
Click image for enlargement.

NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Typhoon Krosa on Friday, Oct. 5 at 5:22 UTC (1:22 a.m. EDT) when it was a powerful "Super Typhoon" with peak sustained winds of 130 knots (149 mph). That made it a category four typhoon on the Saffir-Simpson hurricane scale.

The top image is from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite (GOES), and the image was supplied through the U.S. Naval Research Laboratory.

The image on the bottom is from NASA's CloudSat satellite. The red line through the GOES satellite image shows the vertical cross section of radar, basically what Krosa's clouds looked like sideways. The colors indicate the intensity of the reflected radar energy. The top of Krosa's clouds reach almost up to 15 kilometers, or approximately 9.3 miles high. These high cloud tops indicate a strong storm.

The blue areas along the top of the clouds indicates cloud ice, while the wavy blue lines on the bottom center of the image indicate intense rainfall. Notice that the solid line along the bottom of the panel, which is the ground, disappears in this area of intense precipitation. It is likely that in the area the precipitation rate exceeds 30mm/hr (1.18 inches/hour) based on previous studies.

Rob Gutro
Goddard Space Flight Center
Images credit: NASA/JPL; NASA/JPL; NASA/JPL/Colorado State University/Naval Research Laboratory-Monterey




Super Typhoon Krosa Headed for Taiwan and China

Satellite image of Super Typhoon Krosa
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Typhoon Krosa is a powerful category four typhoon on the Saffir-Simpson scale with peak winds of 130 knots, making it a "Super Typhoon."

Krosa has already brushed by Luzon, and will cross at the Northern tip of Taiwan/Taipei and then deliver a left hook to Fuzhou, Ningbo, Shanghai and Nanjing, China. It is forecast to remain a category 4 typhoon for another 24 hours and then drop to a category 3 for another 24 hours beyond that. Thereafter, it should continue to weaken, but only after it impacts China.

On Oct. 5 at 12:00 UTC (8:00 a.m. EDT), Super Typhoon Krosa was packing maximum sustained winds near 130 knots (149 mph), and powerful gusts to 160 knots (184 mph)! It was centered near 21.8 degrees north latitude and 124.8 degrees west longitude, moving north-northwest near 8 knots (9 mph).

The National Hurricane Center notes that Category Four storms can create storm surges generally 13-18 feet above normal. They also note that terrain lower than 10 feet above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 km). It's likely that China will call for large-scale evacuations as Krosa nears.

Satellite image of Super Typhoon Krosa
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Both the visible image and this infrared image from Oct. 5 at 5:17 UTC (1:17 a.m. EDT or 1:17 p.m. local time) was created by data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the tops of Typhoon Krosa. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). This infrared image shows large areas of strong convection surrounding the core of the storm (in purple), particularly seen in Typhoon Krosa. Krosa's eye is also clearly visible in this image as the yellow area in the middle of the purple region.

Rob Gutro
Goddard Space Flight Center
Images credit: NASA/JPL




Typhoons Lekima, Krosa Menace Western Pacific

There are two active typhoons in the West Pacific region: Lekima and Krosa. Lekima made landfall in central Vietnam as a Category 1 typhoon; Krosa is a Category 4 storm packing 138 mph winds and is expected to affect Taiwan. These images were captured by the Tropical Rainfall Measuring Mission (TRMM) satellite.

Satellite Measurements Show Rain Intensity in Typhoon Lekima

Satellite image of Typhoon Lekima
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This image shows Typhoon Lekima just as the center was bearing down on the coast of Vietnam. The image was taken at 3:05 UTC (10:05 am local time) on Oct. 3, 2007, and shows the horizontal pattern of rain intensity within the storm. Rain rates in the center of the swath are from the TRMM PR, and those in the outer swath come from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM reveals that Lekima still has a closed eye as it nears land although most of the heavy rain (indicated by the dark red areas) is south of the center along the coast. At the time this image was taken, Lekima's sustained winds were estimated at 70 knots (81 mph) by the Joint Typhoon Warning Center. So far, Lekima is being blamed for up to nine deaths in the Philippines and three in Vietnam.

Typhoon Krosa Passes Near Philippines

Satellite image of Typhoon Krosa
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This image shows Typhoon Krosa as it passed through the west-central Philippine Sea about 500 miles northeast of the Philippines in the general direction of Taiwan. The image was taken at 01:33 UTC on Oct. 3, 2007. There are some similarities between Krosa and Lekima: Most of the heavy rain is just south of the center (dark reds) and the maximum sustained winds are comparable, about 75 knots (86 mph). Krosa, however, does not yet have a closed eye in the rain field as it did earlier in its development. But, with plenty of warm open water ahead, the storm still had the potential to intensify, which it did. Less than a day after this image was taken, Krosa's maximum sustained winds had increased to an estimated 120 knots (138 mph).

The Tropical Rainfall Measuring Mission (TRMM) satellite was placed into its low-earth orbit in November 1997. Its primary mission is to measure rainfall from space; however, it has also served as a valuable platform for monitoring tropical cyclones, especially over remote parts of the open ocean. TRMM is a joint mission between NASA and the Japanese space agency, JAXA.

Steve Lang
SSAI/NASA Goddard Space Flight Center
Images credit: Hal Pierce, SSAI/NASA Goddard




NASA's Aqua Satellite Captures Typhoons Lekima and Krosa

Satellite image of storms Krosa and Lekima
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The western Pacific Ocean was a very active place on October 4, 2007. Typhoon Lekima made landfall in Vietnam and was raining on Cambodia, Laos and Thailand. Meanwhile, Typhoon Krosa swirled in the Phillippine Sea with its clouds extending from the Phillippines to Japan's Ryukyu Islands.

This infrared image from Oct. 4 at 4:35 UTC (12:35 a.m. EDT) was created by data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite. Lekima is circular blue area on the left side of this satellite image, and Krosa is depicted on the right side.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the tops of Typhoon Krosa and Lekima. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). This infrared image shows large areas of strong convection surrounding the core of the storm (in purple), particularly seen in Typhoon Krosa. Krosa's eye is also clearly visible in this image as the yellow area in the middle of the purple region.

Powerful Typhoon Krosa in the Open Ocean

On October 4 at 1200 UTC (8:00 a.m. EDT) Krosa was a Category Four Typhoon on the Saffir-Simpson Scale with maximum sustained winds of 120 knots(138 mph), and gusts to 145 knots(166 mph). Krosa was located near 19.9 degrees north latitude and 126.6 degrees east longitude. It's moving to the northwest near 10 knots (11 mph) and is expected to continue moving northwestward. Forecasters noted that the diameter of the eye has increased over the previous six hours from 30 to 35 nautical miles.

Several computer forecast models including those known as the "GFDN, EGRR, ECMWF," and Japanese computer forecast models suggest the storm will make landfall over southeastern China within 4 days.

Lekima Dissipating Over Land

Typhoon Lekima, named after a fruit in Vietnam, landfall late Tuesday in south China's island province of Hainan and made final landfall over north Vietnam in the evening of Oct. 3. It was dissipating as a tropical cyclone over land on Oct. 4.

When Lekima came ashore with sustained winds of 75 mph, it brought heavy rains and flooding. Reports indicated flooded roadways, crop damage and three fatalities. By early morning on Oct. 4, the center of Lekima was located over Laos.

Rob Gutro
Goddard Space Flight Center
Image credit: NASA/JPL




Typhoon Krosa Forms, Strengthens, Heads for Taiwan

Satellite image of Typhoon Krosa
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Tropical cyclone 17 W, meaning the 17th tropical depression in the western Pacific, formed as a tropical depression early on Oct. 2, and strengthened into a Category One typhoon in 12 hours, getting the name "Krosa."

NASA's Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite captured this visible image of Krosa, in the early morning hours of Oct. 2.

On Oct. 2 at 1200 Zulu Time or 8:00 a.m. EDT Krosa's center was near 17.0 north latitude and 131.1 east longitude or 575 miles south-southeast of Okinawa, Japan. Krosa is moving northwest at 4 knots (5 mph) with maximum sustained winds of 65 knots (74 mph) and gusts to 80 knots (92 mph). Forecasters predict that Krosa should continue to track northwestward toward northern Taiwan.

NASA's Aqua Satellite Peers at Krosa's Cloud Tops

Satellite image of Typhoon Krosa
Click image for enlargement.

On Oct. 2 this infrared image taken at 4:41 UTC (12:41 a.m.), created by data from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite captured the cold temperatures of Typhoon Krosa.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm's remnants. The infrared signal does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red). This infrared image shows an area of strong convection (rapidly rising air) in purple.

NASA's QuikSCAT Captures Krosa's Winds

Satellite image of Typhoon Krosa
Click image for enlargement.

This satellite image from the QuikSCAT satellite on was taken Oct. 2 at 9:48 UTC (5:48 a.m. EDT) and depicts the wind speeds in Typhoon Krosa. The center of Krosa is indicated by the purple color. This image depicts wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, around the eye, are shown in purple.

QuikSCAT measurements of the wind strength of Krosa and other tropical cyclones can be slower than actual wind speeds. QuikSCAT’s scatterometer sends pulses of microwave energy through the atmosphere to the ocean surface and measures the energy that bounces back from the wind-roughened surface. The energy of the microwave pulses changes depending on wind speed and direction.

Rob Gutro
Goddard Space Flight Center
Images credit: NASA/JPL