Featured Images
Hurricane Season 2005: Rita
09.30.05
Rita Floods the Texas Gulf Coast
The Neches River flows 670 kilometers (416 miles) through Texas before pouring into Sabine Lake and then the Gulf of Mexico. In its final few kilometers, the river passes through Beaumont, Texas, one of the largest oil refining regions in East Texas. The river is an important conduit from the oil refineries to the Gulf of Mexico and the world. Beaumont and the Neches River were also almost directly in Hurricane Rita’s path when it came ashore on September 24, 2005.
There are some obvious signs of damage in the top image, collected by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite on September 27, 2005. Several permanent structures had been built in the bulge in the river shown here. The structures, probably related to the region’s oil industry, were tossed in Rita’s strong winds, heavy rains, and battering waves. Their positions have shifted compared to their locations on April 18, 2001, lower image. Some of the structures are clearly broken, with sections missing. Along the shore, dark flood water surrounds a series of circular buildings.
These ASTER images are shown in false color. Vegetation is red, and water is dark blue. The large images extend from Beaumont in the north to the Gulf of Mexico. Further flooding is evident near the Gulf in the large images. Credit: NASA images courtesy Jesse Allen, Earth Observatory, using data obtained courtesy of the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team
Rita Engulfs the Chandeleur Islands
The graceful curve of the Chandeleur Islands resembles a multi-boned spine connecting the Mississippi Gulf coast to the delta of the Mississippi River in Louisiana. Like all barrier islands, the Chandeleur Islands form a thin protective wall between the open sea and the mainland, in this case Louisiana’s St. Bernard Parish. The islands absorb the strongest waves, sheltering the mainland during large storms. It is no surprise, then, that barrier islands along the U.S. Gulf Coast changed dramatically in the wake of Hurricane Katrina, and no change is as dramatic as that seen in the Chandeleur Islands.
Hurricane Katrina’s strong winds, storm surge, and battering waves scoured the islands, leaving them reduced or gone altogether. These images of the islands were taken by the Landsat 5 satellite. The top image, taken on September 16, 2005, shows the Mississippi and Alabama coast line, including the line of islands that bore the brunt of Katrina’s fury. The lower images show the northern section of the Chandeleur Islands at full resolution. In the 11 months that passed between October 15, 2004, when the right image was taken, and September 16, 2005, when the left image was taken, the islands have wasted away.
Barrier islands like the Chandeleur Islands are constantly building, eroding, and shifting under the normal erosive and accretion actions of wind and waves. A powerful storm like Katrina can render change that otherwise may have taken many years, and most of the change seen here is probably a result of Katrina. Hurricane Dennis also gave the islands a glancing blow on July 10, 2005, and may be responsible for some of the change.
The other barrier islands shown in the top image were also scoured by Katrina. The large images show that the Ship Islands are now significantly smaller than they were in 2004, and Dauphin Island has been cut in two. To read more about Katrina’s impact on the Gulf Coast, please visit the United States Geological Survey’s Hurricane Katrina Impact Studies page. To learn how NASA technology is contributing to our understanding of coastal erosion, see “LIDAR: In the Wake of the Storm” on the Earth Observatory. Credit: NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of Laura Rocchio, NASA Landsat Project Science Office
Click on image to view animation
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NASA's TRMM spacecraft allows us to look under Hurricane Rita's clouds to see the rain structure on September 19, 2005 at 15Z. Spikes in the rain structure known as 'hot towers' indicate storm intensity. 'Hot Towers' refers to tall cumulonimbus clouds and has been seen as one of the mechanisms by which the intensity of a tropical cyclone is maintained. Because of the size (1-20 km) and short duration (30 minute to 2 hours) of these hot towers, studies of these events have been limited to descriptive studies from aircraft observations, although a few have attempted to use the presence of hot towers in a predictive capacity. Before TRMM, no data set existed that could show globally and definitively the presence of these hot towers in cyclone systems. Aircraft radar studies of individual storms lack global coverage. Global microwave or Infrared sensor observations do not provide the needed spatial resolution. With a ground resolution of 5 km, the TRMM Precipitation Radar provided the needed data set for examining the predictive value of hot towers in cyclone intensification.
At the time the data was taken, this storm was classified as a Tropical Storm with winds off 55 knots and a pressure of 994mb. The existence of these 18 km towers in the eye wall alerted researchers that this storm was going to rapidly intensify. Within 48 hours of this dataset, the storm was a very strong category 4 hurricane.
Credit: Lori Perkins/NASA
September 30, 2005 - 5:28 p.m. Eastern
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Image above: This dramatic image shows the structure of exceptionally tall rain clouds buried in the core of Tropical Storm Rita, as revealed by NASA's Tropical Rainfall Measurement Mission (TRMM) satellite. Red colors show the tallest heavy-rain producing "hot towers," two of which exceeded 60,000 feet in altitude. Heat energy released inside these giant clouds likely started to intensify Rita, which became a Category 5 hurricane soon thereafter.
September 28, 2005 - 2:28 p.m. Eastern
Click on image to view animation. Click here to view a high resolution version of the above image.
This animation shows rain accumulation from Hurricane Rita from September 18 through 25, 2005 based on data from the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis. Satellite cloud data from NOAA/GOES is overlaid for context. The accumulation is shown in colors ranging from green (less than 30 mm of rain) through red (80 mm or more). The TRMM satellite, using the world's only spaceborne rain radar and other microwave instruments, measures rainfall over the ocean.
Credit: NASA. Image and Animation produced by the Scientific Visualization Studio at NASA GSFC.
Click here to see higher resolution images of the Before image and the After image.
Hurricane Rita’s fifteen-foot storm surge and heavy rains caused widespread flooding along the Louisiana coastline. The storm came ashore near the Texas and Louisiana border on September 24, 2005, and the region was still flooded two days later, when the Moderate Resolution Imaging Spectroradiometer (MODIS) captured the bottom image. In the false color image, water is black or dark blue where it is colored with mud. The storm burst through levees lining canals, lakes and bayous throughout southeastern and central Louisiana. Water poured into low-lying areas, leaving much of the region flooded to such a degree that the large lakes that lined the coast are no longer distinguishable from each other. Though buildings and farms have largely been destroyed, the death toll remains low because most people evacuated before the storm struck.
As Rita moved inland, the storm’s heaviest rains fell on Louisiana. Rain-triggered flooding is obvious in the upper right corner of the bottom image. Bare farmland formed a tan grid in the area on September 21, upper image. On September 26, standing water has turned the fields blue.
Credit: NASA. Images courtesy of the MODIS Rapid Response Team at NASA GSFC.
Click on image to see higher resolution image.
After forming east of the Turks and Caicos, Rita moved west and sideswiped the Florida Keys before entering the Gulf of Mexico where it strengthend into the 3rd most powerful hurricane on record (in terms of central pressure). Rita eventually made landfall near the Texas-Louisiana border as a Category 3 storm. After making landfall, Rita weakened into a tropical depression and moved northeastward through central Arkansas and into southeast Missouri.
The image about shows the Multi-satellite Precipitation Analysis (MPA) rainfall totals due solely to Rita are shown for the period September 18-26, 2005 with storm symbols marking the storm track. The highest rainfall totals are over coastal Louisiana where a swath of 8 to 10 inch amounts (yellow and orange areas) extends eastward from the Texas border to near Morgan City. Parts of the Keys and far southwestern peninsular Florida received up to 5 inches from Rita (green areas). Overall, the inland rainfall totals across the central Mississippi valley were not very high, generally less than 4 inches (light green to blue), as Rita rather quickly moved off to the northeast.
The Tropical Rainfall Measuring Mission (TRMM) satellite has been measuring rainfall over the tropics since its launch in 1997. The TRMM-based, near-real time MPA at the NASA Goddard Space Flight Center provides estimates of rainfall over the global tropics.
TRMM is a joint mission between NASA and the Japanese space agency JAXA.
Credit: NASA. Image produced by Hal Pierce (SSAI/NASA GSFC) and captioned by Steve Lang (SSAI/NASA GSFC).
Click on image to view movie
Movie above: This movie of Hurricane Rita was compiled from satellite images from September 19-24, 2005. Like hurricane Katrina, the storm first organized from a group of thunderstorms in the Bahamas. It plowed across south Florida and grew rapidly in the very warm waters of the Gulf to category 5 storm on the Saffir-Simpson scale. Rita made landfall in the early morning hours of Saturday, September 24 on the Texas/Louisiana border, sparing Galveston and Houston from the full brunt of the storm. This movie is made using visible and infrared cloud images from the National Oceanic and Atmospheric Administration's (NOAA) (Geostationary Operational Environmental Satellite) GOES-12 satellite, overlaid on a color-coded map from NASA's Landsat satellite.
Credit: NASA-GSFC, data from NOAA GOES
Tropical Depression Rita Brings Rain to the North
On Monday, September 26, 2005 at 5 a.m. EDT, the once mighty Hurricane Rita has been downgraded to a tropical depression and her rains have stretched northward into the eastern U.S. At 5 a.m. EDT, the center of Tropical Depression Rita was located near latitude 40.8 north...and longitude 86.8 west...or 80 miles north northwest of Indianapolis, Indiana.
Maximum rainfall amounts from Tropical Depression Rita are expected to range from 1 to 2 inches over parts of the Ohio valley and the southeast.
Flood and flash flood watches are still in effect for portions of Mississippi, Alabama and the Florida panhandle as Rita's train of moisture pushes east.
The depression is now moving north northeast at 30 mph. This general motion is expected to continue. Rita will weaken and become absorbed by a frontal wave later this morning. Maximum sustained winds are 15 mph with higher gusts. The minimum central pressure was 1006 millibars or 29.71 inches.
Following are some of the highest rainfall totals measured in various states as of 3.a.m. EDT on September 26, 2005:
Alabama, town of Atmore: 4.30 inches (Camden: 4.28 inches)
Arkansas, town of Boughton: 5.88 inches (Hot Springs: 5.58 inches)
Illinois, Scott Air Force Base: 2.16 inches (Champaign/Urbana: 1.60 inches)
Indiana, Eagle Creek Airport: 2.26 inches (Terre Haute: 1.65 inches)
Kentucky, city of Paducah: 1.40 inches
Louisiana, town of Bunkie: 16.00 inches (LaPlace: 12.45 inches)
Mississippi, town of Greenville: 8.37 inches (Natchez: 7.80 inches)
Missouri, town of Myrtle: 2.15 inches
Texas, town of Center: 8.48 inches (Beaumont/Port Arthur: 8.89 inches)
Click here for more storm total rainfall amounts in inches through 3 a.m. EDT, from The National Weather Service's Hydrometeorological Prediction Center
Text Derived from the National Weather Service's Hydrometeorological Prediction Center report.
Credit: Rob Gutro, NASA Goddard Space Flight Center
The MODIS instrument on the Terra satellite captured this image of Hurricane Rita as it made landfall on the Gulf Coast on September 24, 2005. Credit: NASA image courtesy Jeff Schmaltz, from the MODIS Rapid Response Team at NASA GSFC
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The MODIS instrument on the Aqua satellite captured this image of Hurricane Rita as it started making landfall on the Gulf Coast on September 23, 2005. Credit: NASA image courtesy Jeff Schmaltz, from the MODIS Rapid Response Team at NASA GSFC
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The onslaught from the 2005 hurricane season continues with the arrival of Hurricane Rita, the second Category 5 storm to theaten the Gulf of Mexico in less than a month. As it was passing south of the Florida Keys on the afternoon of the September 20, 2005, Hurricane Rita was in the process of slowly intensifying from a Category 1 storm into a Category 2 storm. However, upon entering the Gulf of Mexico, Rita tapped into a deep layer of very warm water located in the southeast part of the Gulf associated with the loop current. This allowed Rita to undergo a process known as rapid deepening, which transformed it into a powerful Category 5 hurricane with the 3rd lowest pressure ever recorded in the Atlantic Basin.
The Tropical Rainfall Measuring Mission (TRMM) satellite is one of many satellites being used to monitor hurricanes and typhoons. Launched in November of 1997 to measure rainfall over the Tropics, TRMM has proven to be a valuable platform for observing tropical cyclones and can provide unique images and information on these storms. This first image was taken at 09:07 UTC (5:07 am EDT) 21 September 2005 and captures Rita during its period of rapid deeping in the southeastern Gulf of Mexico just before it became a Category 4 hurricane. The image shows the horizontal distribution of the rain intensity within Rita as detected by TRMM's sensors. Rain rates in the central portion of the swath are from the TRMM Precipitation Radar (PR), the only radar that can measure precipitation from space. The PR is able to provide fine resolution rainfall data and details on the storm's vertical structure. Rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). At the time of the image, Rita was still a Category 3 storm with maximum sustained winds reported at 105 knots (121 mph) by the National Hurricane Center (NHC). Although the center does not fall within the PR swath in this image, TRMM reveals that Rita has a well-defined, closed eye surrounded by a large inner ring of moderate to heavy rain (green and red areas). Combined with the distinct banding in the surrounding rain field (green arcs), these features observed by TRMM show that Rita is already a mature hurricane with a well-developed circulation. The heavy rain near the center of the storm indicates where condensational heating, associated with the phase change of water vapor into liquid water, is occuring within the storm. This heat release is what drives the storm's circulation. Rita would reach Category 4 intensity soon after this image was taken.
Rita continued to intensify into the evening of the 21 September, reaching Category 5 intensity with maximum sustained winds recorded at 175 mph. Hurricane hunter aircraft recorded a minimum central pressure of 897 mb, placing Rita behind only Hurricane Gilbert in 1988 and the Great Labor Day Hurricane of 1935 in terms of the lowest central pressure ever measured in the Atlantic Basin. This second image was taken by TRMM at 14:42 UTC (10:42 am EDT) on 22 September and provides a spectacular view of Rita courtesy of the TRMM PR, which passed directly over the eye. TRMM shows the inner details of a Category 5 Rita. The inner eyewall, visible as the innermost ring of moderate (green) to heavy (red) rain, is surrounded by an outer eyewall, the larger conentric ring of moderate (green) to heavy (red) rain. This double eyewall structure occurs in mature, intense tropical cyclones and is part of the eyewall replacement cycle wherein the an outer eyewall forms around the inner eyewall. The outer eyewall eventually contracts and replaces the inner eyewall. The third image was taken at the same time and shows a vivid 3D perspective of Rita. The vertical height of the isosurface (15 dBZ) is determined by the height of the precipitation-sized particles within the storm as detected by the TRMM PR. The northern half of the inner eyewall is visible by the tall towers (in red). These towers reach up to 15 km in height. The outer eyewall is also visible by the somewhat lower surrounding ring (light red tops). At the time of these images, Rita was a Category 5 storm with maximum sustained winds reported at 145 knots (167 mph) by NHC.
Fortunately, hurricanes do not maintain these extreme intensities for long. As Rita moved across the Gulf away from the loop current, it slowly began to weaken. The final image was taken by TRMM at 13:45 UTC (9:45 am EDT) on September 23 as Rita was passing just south of the central Louisiana coast. The center of the storm lies within the TMI swath. Areas of very heavy rain (dark red areas) associated with an outer rainband are approaching the the Louisiana coast. The eyewall is not as symmetrical as before and is a sign of weakening. Rita, however, was still a strong storm with sustained winds of 120 knots (138 mph) when this image was taken.
TRMM is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA). Credit: NASA. Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).
NASA Data Helps Track Heat Potential Fueling Rita
Tropical Cyclone Heat Potential field in the Gulf of Mexico during September 22, 2005. The path of Hurricane Rita is indicated with circles spaced every 3 hours with their size and color representing intensity (see legend). This hurricane intensified to category 5 as it traveled over the Loop Current and a warm core eddy (the finger of red and yellow). Rita diminished to category 3 as its path went over a region of lower TCHP (and cooler waters) outside the Loop Current and ring. The diamonds indicate the National Hurricane Center predicted track and intensity as it makes landfall, and are spaced by 24 hours. Altimeter data on NASA's Jason-1, the US Navy's GFO, and the European Envisat satellites provide sea surface height data used in generating the TCHP fields.
Image credit: NASA/JPL/NOAA/AOML
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Rita's Rainfall Rates as Measured by TRMM
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NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft observed this view of Hurricane Rita on September 23, 2005 at 12:52 pm EDT. At this time the storm was a category 4 hurricane with a minimum pressure of 924 mb, and sustained winds of 120 knots. The cloud cover is taken by TRMM's Visible and Infrared Scanner(VIRS) and the GOES spacecraft. The rain structure is taken by TRMM's Tropical Microwave Imager (TMI). It looks underneath of the storm's clouds to reveal the underlying rain structure. Blue represents areas with at least 0.25 inches of rain per hour. Green shows at least 0.5 inches of rain per hour. Yellow is at least 1.0 inches of rain and red is at least 2.0 inches of rain per hour. Click on image to view animation (no audio - 9.7 b) Credit: NASA
Map of Rita's Current Track and Speed
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This sea surface height map of the Gulf of Mexico, with the Florida peninsula on the right and the Texas-Mexico Gulf Coast on the left, is based on altimeter data from four satellites including NASA's Topex/Poseidon and Jason-1. Red indicates a strong circulation of much warmer waters, which can feed energy to a hurricane. This area stands 35 to 60 centimeters (about 13 to 23 inches) higher than the surrounding waters of the Gulf. The actual track of a hurricane (indicated by the black line on the image) is primarily dependent upon steering winds, which are forecasted through the use of atmospheric models. However, the interaction of the hurricane with the upper ocean is the primary source of energy for the storm. Hurricane intensity is therefore greatly affected by the upper ocean temperature structure and can exhibit explosive growth over warm ocean currents and eddies. Eddies are currents of water that run contrary to the direction of the main current. After gaining strength on its path across the warm waters of a Gulf of Mexico circulation feature called the Loop Current, the current forecasted track of the hurricane will continue past a warm-water eddy called the Eddy Vortex, located in the north central Gulf, south of Louisiana. Sustained wind speeds in MPH are indicated in white.
The Jason satellite carries a dual-frequency radar altimeter. This instrument beams microwave pulses-at 13.6 and 5.3 Gigahertz, respectively-downward toward the Earth. To determine the ocean's height, the instrument precisely measures the time it takes for the microwave pulses to bounce off the surface and return to the spacecraft. This measure, multiplied by the speed of light, gives the range from the satellite to the ocean surface.
The joint U.S.-French Topex/Poseidon mission is managed by the JPL for NASA's Earth Science Enterprise, NASA Headquarters, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. Research on Earth's oceans using Jason and other space-based capabilities is conducted by NASA's Earth Science Enterprise to better understand and protect our home planet. For more information on Topex/Poseidon, see http://topex-www.jpl.nasa.gov. Click on image to enlarge. Credit: NASA/JPL/University of Colorado
On September 22 at 1:30 a.m. C.T., Rita was a category 5 hurricane with sustained winds of 150 mph and a central pressure of 897 millibar at the time the data used to create these AIRS images were retrieved. Storm position is approximately 470 southeast of Galveston, Texas.
Click on image to view full resolution
The image above shows how the storm looks through an AIRS Infrared window channel. Window channels measure the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures in dark purple are associated with high, cold cloud tops that make up the top of the hurricane. The infrared signal does not penetrate through clouds, so the purple color indicates the cool cloud tops of the storm.
The infrared image reveals a very well developed eye at the center of the storm. The red at the center of the eye indicates medium altitude clouds are obscuring the eye, and the blue ring delineates the towering thunderstorms of the eye wall ring. In cloud-free areas, the infrared signal is retrieved at the Earth's surface, revealing warmer temperatures except over open water (which appears colder due to lower emissivity). Cooler areas are pushing to purple and warmer areas are pushing to red. Green generally indicates the presence of clouds. Notice that some high cold clouds as indicated in the infrared do not show up much in the microwave. Microwaves are strongly affected by rain and ice crystals, so some high clouds are almost certainly not raining and may be pretty thin (like cirrus).
Image credit: NASA
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In this image created from the AIRS microwave sensor, the large blue swath that previously extended into the Gulf is gone (refer to previous images below). The big blue swath was a relatively clear area ahead of Rita that was over the Gulf and the Atlantic. Now Rita has moved closer to land and all the area over the ocean is taken up by the storm. If there is clear air in front, it is over land and thus will show up hot because of the emissivity of the land. Green generally indicates the presence of clouds. The blue areas around the eye are indicative of very high, cold cloud tops crowned by ice. These cloud towers are indicative of strong convection and rain - these are strong high altitude thunderstorms in the eye wall.
Image credit: NASA
Rita Rides Closer to Texas
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The MODIS instrument on the Aqua satellite captured this image of Hurricane Rita on September 22, 2005 as it blasts across the warm waters of the Gulf of Mexico and heads for the coastline of Texas. Credit: NASA image courtesy Jeff Schmaltz, from the MODIS Rapid Response Team at NASA GSFC
Rita's Rising Waters Threaten the Gulf Coast
The Gulf Coast from the Mississippi Delta through the Texas coast is shown in this satellite image from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) overlain with data from the Shuttle Radar Topography Mission (SRTM), and the predicted storm track for Hurricane Rita. The prediction from the National Weather Service was published Sept. 22 at 4 p.m. Central Time, and shows the expected track center in black with the lighter shaded area indicating the range of potential tracks the storm could take.
Low-lying terrain along the coast has been highlighted using the SRTM elevation data, with areas within 15 feet of sea level shown in red, and within 30 feet in yellow. These areas are more at risk for flooding and the destructive effects of storm surge and high waves.
+Simulated view of potential floodingAbout the animation: This simulated view of the potential effects of storm surge flooding on Galveston and portions of south Houston was generated with data from the Shuttle Radar Topography Mission. Although it is protected by a 17-foot sea wall against storm surges, flooding due to storm surges caused by major hurricanes remains a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments.
Image and animation credit: NASA/JPL/NGA
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Hurricane Rita's Rainfall - September 22
Hurricane Rita is now a Category 5 storm and on Sept. 21, 2005, was declared the third strongest hurricane in recorded history. New 3-D satellite images show the rainfall distribution inside the storm and the surrounding warm water that continues to fuel this hurricane heat engine.
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NASA's Tropical Rainfall Measuring Mission (TRMM) satellite observed the distribution of rainfall inside Hurricane Rita on Sept. 22, 2005. At the time of observation, this Category 5 hurricane had a minimum pressure of 898 millibars, sustained winds of 170 mph and a 17-mile wide eye. Maximum rainfall, shown in red, equals two or more inches of rain per hour. Click on image above to view animation (no audio - 11.2 Mb). Credit: NASA/JAXA
This visualization shows the sea surface temperature from September 17 to September 21 when temperatures in the Gulf of Mexico remained one to two degrees warmer than the 82 degree minimum needed to sustain a hurricane. Every area in yellow, orange or red represents 82 degrees F or above. Temperature data is from the AMSR-E instrument on the Aqua satellite, while the cloud images of Hurricane Rita were taken by the Imager on the GOES-12 satellite. Click on image above to view animation (no audio - 3.7 Mb.) Credit: NASA
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Rita's Hot Towers
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NASA's Tropical Rainfall Measuring Mission (TRMM) satellite reveals a remarkable feature in this 3-D cat scan of Hurricane Rita - a pair of gigantic chimney clouds reaching more than 11 miles high. That is equivalent to 60,000 feet, or twice as high as a commercial airplane's cruising altitude. TRMM observed these hot towers in Hurricane Rita on September 19, 2005 during a period of brief intensification. Click on image to view animation (no audio - 6 Mb) Credit: NASA/JAXA
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Hurricane Roars Through a Warm Gulf - Updated Image
Image above: This sea surface height map of the Gulf of Mexico, with the Florida peninsula on the right and the Texas-Mexico Gulf Coast on the left, is based on altimeter data from four satellites including NASA's Topex/Poseidon and Jason. Red indicates a strong circulation of much warmer waters, which can feed energy to a hurricane. This area stands 35 to 60 centimeters (about 13 to 23 inches) higher than the surrounding waters of the Gulf.
The actual track of a hurricane is primarily dependent upon steering winds, which are forecasted through the use of atmospheric models. However, the interaction of the hurricane with the upper ocean is the primary source of energy for the storm. Hurricane intensity is therefore greatly affected by the upper ocean temperature structure and can exhibit explosive growth over warm ocean currents and eddies. Eddies are currents of water that run contrary to the direction of the main current.
According to the forecasted track through the Gulf of Mexico, Hurricane Rita will continue crossing the warm waters of a Gulf of Mexico circulation feature called the Loop Current and then pass near a warm-water eddy called the Eddy Vortex, located in the north central Gulf, south of Louisiana.
Image credit: NASA/JPL/University of Colorado
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Monster Rita Barrels Across the Gulf
Rita, now a Category 5 hurricane, was captured by the MODIS instrument on the Aqua satellite in this image from September 21, 2005. For the latest prediction information on Rita, consult the National Hurricane Center website.
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Rita's Rainfall Intensifies on September 21
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NASA's TRMM spacecraft is used to understand Hurricane Rita. TRMM observed this view of Hurricane Rita on September 21, 2005 at 0909Z. At this time the storm was a category 3 hurricane with a minimum pressure of 956mb, sustained winds of 105 knots, and a 25 nautical mile eye diameter. The cloud cover is taken by TRMM's Visible and Infrared Scanner(VIRS) and the GOES spacecraft. The rain structure is taken by TRMM's Tropical Microwave Imager (TMI). It looks underneath of the storm's clouds to reveal the underlying rain structure. Blue represents areas with at least 0.25 inches of rain per hour. Green shows at least 0.5 inches of rain per hour. Yellow is at least 1.0 inches of rain and red is at least 2.0 inches of rain per hour. Click on image to view animation (no audio - 9.7 Mb). Credit: NASA
Rita Roars Through a Warm Gulf
Image above: This sea surface height map of the Gulf of Mexico, with the Florida peninsula on the right and the Texas-Mexico Gulf Coast on the left, is based on altimeter data from four satellites including NASA's Topex/Poseidon and Jason. Red indicates a strong circulation of much warmer waters, which can feed energy to a hurricane. This area stands 35 to 60 centimeters (about 13 to 23 inches) higher than the surrounding waters of the Gulf.
The actual track of a hurricane is primarily dependent upon steering winds, which are forecasted through the use of atmospheric models. However, the interaction of the hurricane with the upper ocean is the primary source of energy for the storm. Hurricane intensity is therefore greatly affected by the upper ocean temperature structure and can exhibit explosive growth over warm ocean currents and eddies. Eddies are currents of water that run contrary to the direction of the main current.
According to the forecasted track through the Gulf of Mexico, Hurricane Rita will continue crossing the warm waters of a Gulf of Mexico circulation feature called the Loop Current and then pass near a warm-water eddy called the Eddy Vortex, located in the north central Gulf, south of Louisiana.
Image credit: NASA/JPL/University of Colorado
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At 6:05 a.m. EDT on Wednesday, September 21, Hurricane Rita's Category 4 hurricane force winds were observed by NASA’s QuikSCAT satellite. According to the latest report from the National Hurricane Center at 11 a.m. EDT, Hurricane Rita remains an extremely dangerous hurricane.
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, shown in purple, surround the center of the storm. The 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, giving scientists a way to monitor wind around the world.
At 11 a.m. EDT on Wednesday, September 21, the eye of Hurricane Rita was located near Latitude 24.3 north and longitude 85.9 west, or about 755 miles east-southeast of Corpus Christi, Texas. Rita is moving toward the west near 13 mph, and that motion is expected to continue for the next 12-24 hours. Image Credit: NASA JPL
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On Tuesday, September 20 at 2 p.m. ET, Hurricane Rita's sustained winds reached 100 miles per hour. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this image of Rita at 18:35 UTC or 2:35 p.m. ET.
At that time, a hurricane warning was in effect for all of the Florida Keys as well as from south of Florida City on the Florida southeast coast southward to East Cape Sable. The warning extended northward to Chokoloskee on the southwest Florida coast. The warning remained in effect for the Cuban provinces of Matanzas, ciudad de Habana, and La Hanaba.
At 2 p.m. ET, the center of Hurricane Rita was located near latitude 23.9 north and longitude 81.7 west or about 50 miles (80 km) south of Key West, Florida and about 65 miles (105 km) northeast of Havana, Cuba.Rita was moving westward near 15 mph, and the motion was expected to continue. The core of the hurricane was expected to move over the Florida Straits in the next 24 hours.
Less than 24 hours later, at 8 a.m. ET on Wednesday, September 21, satellite data suggests that Rita has strengthened into a Category 4 storm with sustained winds of 135 mph. She was located 195 miles west of Key West, Florida and moving on a westward track into the Gulf.
Storm surge flooding elsewhere in the Florida Keys and south Florida is expected to subside on Wednesday, September 21. Rita is expected to produce additional rainfall accumulations of 1 To 3 inches over portions of extreme southern Florida and the Florida keys. + High resolution image Credit: NASA images courtesy Jeff Schmaltz, from the MODIS Rapid Response Team at NASA GSFC
Rita Brushes the Florida Keys and Heads into the Gulf of Mexico
After the immense devastation brought by Hurricane Katrina, all eyes are on Hurricane Rita as it passes the Florida Keys and threatens the Gulf of Mexico. The Tropical Rainfall Measuring Mission (TRMM) satellite is one of a number of satellites being used to monitor Hurricane Rita and storms like it. Launched back in November of 1997 to measure rainfall over the Tropics, TRMM has proven itself to be a valuable platform for observing tropical cyclones, which include hurricanes and typhoons.
Rita formed from a tropical disturbance east of the Turks and Caicos Islands into a depression (TD #18) on evening of the 17 September 2005 (local time). The system moved west through the Caicos and strengthened into a tropical storm on the afternoon (local time) of the 18th before entering into the southern Bahamas. The first image (above) was taken by TRMM at 15:57 UTC (11:57 am EDT) on 19 September 2005 as Rita was passing through the southern Bahamas. The image shows the horizontal distribution of rain intensity within Rita as obtained from TRMM's sensors. Rain rates in the center part of the swath are from the TRMM Precipitation Radar (PR), the only radar capable of measuring precipitation from space. The PR can provide fine resolution rainfall data and details on the vertical structure. Rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). At the time of the image, Rita was a tropical storm with maximum sustained winds reported at 55 knots (63 mph) by the National Hurricane Center (NHC). A well-defined closed eye is not visible in this image as Rita is still in the process of organizing. However, there is evidence of banding in the rain features southwest and northeast of the center (green and blue arcs), and an area of heavy rain is present on the southwest side of Rita's center (red area). + High resolution image
The second image (above), which was taken at the same time, shows a 3D perspective of Rita courtesy of the TRMM PR. The 3D isosurface (defined by the 15 dBZ echo intensity) is color-coded to show the vertical height of precipitation-sized particles within the storm. An immense tower (in red) reaches up to 17 km near the center and is associated with the area of heavy rain shown in the previous image. Tall towers are often a sign of future intensification. As water vapor condenses into tiny cloud droplets, heat is released. This heat, known as latent heat, is what drives the storm's circulation. It is most effective when it occurs near the center of the storm. The cloud droplets form into rain, which can be detected by the radar. Click on image to view animation. + High resolution image
The last image was taken at 08:28 UTC (4:28 am EDT) on the 20th of September as Rita was passing through the Florida Straits. Although the center of Rita does not fall within the PR swath, it is obvious from TRMM that Rita is becoming better organized. A ragged eye is present surrounded by areas of moderate rain (green areas) with good banding in the outer rainbands, all signs that the storm's circulation is improving. Rita was still a tropical storm at the time of this image with sustained winds of 60 knots (69 mph), but by early afternoon the same day, Rita would become a Category 2 hurricane as it passed south of the Florida Keys headed for the Gulf of Mexico. + High resolution image TRMM is a joint mission between NASA and the Japanese space agency JAXA. Credit: NASA/Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).
A tropical depression formed in the Bahamas on September 17, 2005. Once it was organized enough to have winds of over 62 kilometers per hour (39 miles per hour), it was classified as a tropical storm and given the name Rita, becoming the 17th named storm system of the 2005 hurricane season. With the season not yet over, this makes 2005 already the 5th most active storm system since naming records were started in 1851. According to the National Hurricane Center, 21 tropical storms formed in 1933, 19 developed in 1995 and 1887, and 18 formed in 1969. Rita is also the earliest “R” named storm in a season.
Rita crossed the threshold to tropical storm status around 5 pm (local time) on September 18, 2005. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this image of Rita roughly fives hours earlier at 11:40 a.m. while the storm was still an organizing tropical depression. The classical spiral structure of a hurricane is not yet full formed, nor is there a well organized eye of the storm, but these nascent features of the developing system are apparent already.
Forecasters are particularly concerned about Rita as it is projected to pass through the Florida Key Islands as it is reaching hurricane strength. The storm track projections as of September 19 have it crossing the Gulf of Mexico to make landfall in the general vicinity of southern Texas, but forecasting hurricanes several days in advance is still an uncertain science and there are fears that Rita could turn in the Gulf and head into areas recently battered by Katrina. + High resolution image Credit: NASA image created by Jesse Allen, Earth Observatory, using data provided courtesy of the MODIS Rapid Response team.
