Category: Earth Observation

Image credit: ESA

The European Space Agency is helping to track the movement of Hurricane Isabel using its ERS-2 spacecraft, and released this photo of the storm Thursday morning as it menaced the East Coast of the US. ERS-2 has also been gathering other information about the storm, including sea surface temperatures, wind and rainfall levels. Isabel is a Category 2 hurricane, and expected to make landfall in the early afternoon on Thursday in North Carolina.

As Hurricane Isabel converges on the US East Coast, a veteran ESA spacecraft has provided meteorologists with crucial insights into the underlying pressure system powering the storm.

An entire flotilla of satellites is being kept busy tracking Hurricane Isabel in visible and infrared light, as well as gathering additional measurements of local sea surface temperature, wind and rainfall levels. ESA spacecraft ERS-2 has made the picture more detailed still by discerning the wind speed and direction around the hurricane’s cloud and rain-wracked heart.

ERS-2 instruments include a C-band scatterometer, which works by sending a high-frequency radar pulse down to the ocean, then analysing the pattern of backscatter reflected back again. Scatterometers are particularly useful in measuring wind speed and direction at the sea surface, by detecting signature scatter from ripples on the water caused by wind.

ERS-2’s scatterometer is less sensitive than comparable space-based instrumentsto rain or bad weather, and can gather data both day and night. This makes it invaluable as an early detector of Atlantic storms ? especially in the current hurricane season.

The Isabel data was obtained mid-afternoon Wednesday at one of ESA?s ground stations in Gatineau Canada, then rapidly delivered to meteorology offices worldwide. At the Reading-based European Centre for Medium-Range Weather Forecasts (ECMWF), it was analysed against the surface wind pattern predicted by their existing software simulation of Isabel, run on powerful supercomputers.

“The ERS wind data is very valuable to us,” said Hans Hersbach of ECMWF. “It shows differences with our analysis, for instance a lack of inward wind flow into the centre. By assimilating the data into our analysis we improve our forecasting skills.

“The ESA scatterometer data was routinely assimilated into our analysis after 1997, until it become no longer available early this century. Now the service has been resumed we are making use of it once more.”

ESA’s ERS-2 has been in orbit since 1995, but the service from the scatterometer was interrupted in 2001. A degradation in attitude control prevented access to the data. Meteorologists lost a valuable window on the weather ? until this summer, when after two-and-a-half-years of effort, new processing software developed by the Belgian Royal Military Academy (RMA) compensated for the degradation and regained access to scatterometer measurements.

The software algorithm was installed in ground stations at Kiruna in Sweden, Maspalomas in the Canary Islands Gatineau in Canada as well as Frascati in Italy, with an additional installation planned for West Freugh in Scotland. The new service began at the end of August, just in time for Hurricane Isabel’s dramatic arrival.

To maintain future continuity of scatterometer coverage, a new more advanced scatterometer instrument called ASCAT is part of the payload for ESA?s MetOp mission, currently due to launch in 2005.

Inside a hurricane
Hurricanes are large powerful storms that rotate around a central area of extreme low pressure. They arise in warm tropical waters that transfer their heat to the air. The warmed air rises rapidly, in the process creating low pressure at the water surface. Winds begin rushing inwards and upwards around this low-pressure zone.

Currently classed at Category Two on the five-point Saffir-Simpson Hurricane scale, Isabel originated in the eastern Atlantic last week. It is currently moving northwest at only about 24 kilometres an hour but winds within it are rotating at about 160 km per hour. Meteorologists forecast the hurricane will make landfall in North Carolina on Thursday.

Original Source: ESA News Release

Astronauts on board the International Space Station captured several images of Hurricane Isabel on Saturday as they flew over at an altitude of 386 kilometres. At the time, it was a category 5 storm but it has since weakened to category 2. It still packs a punch, though, and East Coast residents of the United States are preparing the for the storm’s landfall some time on Thursday.

Image credit: NASA

NASA’s Aqua satellite took this overhead view of Hurricane Isabel on September 14, 2003 while it was 650 km north of Puerto Rico. The image was acquired using Aqua’s Moderate Resolution Imaging Spectroradiometer (MODIS). Isabel is currently a category 4 hurricane, with winds as high as 220 km/h – this is about 15 km/h slower than they were on the weekend. Residents, businesses, and even the military are taking precautions in case Isabel doesn’t lose strength and hits the coast of the North America.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard NASA’s Aqua satellite captured this image of Hurricane Isabel September 14, 2003. In this image Hurricane Isabel is approximately 400 mi north of Puerto Rico.

*** Note: We’re tracking more satellite photos of the hurricane in the Universe Today forums. Click here to see the updates each day.

Image credit: ESA

The European Space Agency’s Envisat environmental satellite captured this image of a burning oil pipeline in northern Iraq. The immense black cloud stretched over thousands of square kilometres in the valley between the Tigris and Euphrates rivers. The pipeline transfers oil from Kirkuk to Baija, and another photo from Envisat shows how the area looked before the fire.

A burning oil pipeline in northern Iraq produced an immense cloud of black smoke that stretched across thousands of square kilometres, in this image acquired by Envisat?s Medium Resolution Imaging Spectrometer.

The smoke cloud is visible in the centre of this image of the alluvial plain occupied by the valley of the river Tigris (flowing from the top centre of the image) and the Euphrates (flowing from the top left corner).

The Medium Resolution Imaging Spectrometer (MERIS) on ESA?s Envisat environmental satellite acquired the image on 30 August, the same day as the media reported a fire affecting a segment of oil pipeline near the town of Hawija.

The pipeline transports crude oil from the oil-rich city of Kirkuk ? seen here in grey, on the Tigris River – to Baija, where the country?s largest oil refinery is located. For comparison the second MERIS image shows the same area three days earlier, before the pipeline had been damaged.

The dense cloud of smoke has an extent comparable to the Iranian lake Urmia (which has an area of 4700 square kilometres), seen in turquoise colour towards the top right of the image. Authorities stated it took two days to bring the fire under control.

These three-band MERIS images have a resolution of 1200 metres and were processed by Hamburg-based Brockmann Consult.

Original Source: ESA News Release

Image credit: NASA

Weather forecasters are turning to data from a fleet of satellites to help predict how conditions might turn into hurricanes that could ravage the coastal areas of Eastern North America. Tropical storms typically appear off the coast of Africa from June to November; some of these will turn into hurricanes depending on many factors. Satellites can now spot many of the warning signs, including a sea surface temperature of at least 27.8 degrees Celsius, rotating winds above the ocean, air temperature, humidity, and finally rainfall intensity.

Every year, from June 1 to November 30, the Atlantic Ocean becomes a meteorological mixing bowl, replete with all the needed ingredients for a hurricane recipe. Forecasters who seek to monitor and understand hurricanes are increasingly turning to a cadre of NASA satellites and instruments, including several from NASA’s Jet Propulsion Laboratory, Pasadena, Calif., that serve up a feast of information on these awesome storms.

Typically, during the peak of hurricane season, from late August to mid-September, tropical cyclones of interest to U.S. coastal regions form around the Cape Verde Islands off Africa. NASA satellites are critical for helping forecasters determine if all of the ingredients are coming together to create a hurricane. If a hurricane forms, it is critical to know how strong it may be, and which coastal communities or sea lanes will be at risk.

NASA provides researchers and forecasters with space-based observations, data assimilation and computer climate modeling. NASA-sponsored measurements and modeling of global sea surface temperature, precipitation, winds and sea surface height have also improved understanding of El Ni?o and La Ni?a events, which respectively tend to suppress and enhance Atlantic and Gulf hurricane development.

Thirty years ago, meteorologists were unable to see the factors in hurricane formation and could only spot a hurricane with still pictures from the Television Infrared Operational Satellite – Next-generation (Tiros-N) spacecraft. Over the past 10 years, visible and infrared satellite sensors were the workhorses for monitoring hurricanes. Today, multiple NASA satellites exploit everything from radar pulses to microwaves for the purpose of enhancing forecasts, providing data to researchers several times a day.

The first ingredient in the hurricane recipe is a sea surface temperature of at least 27.8 degrees Celsius (82 degrees Fahrenheit). Unlike traditional infrared satellite instruments, the Aqua satellite’s Advanced Microwave Scanning Radiometer E and the Tropical Rainfall Measuring Mission’s microwave imager can detect sea surface temperatures through clouds. This valuable information can help determine if a tropical cyclone is likely to strengthen or weaken. The joint U.S.-French Jason-1 satellite altimeter, managed by JPL, provides data on sea surface height, a key measurement of ocean energy available to encourage and sustain hurricanes.

Another necessary ingredient is rotating winds over the ocean’s surface, precursors to tropical cyclone development. The NASA-provided and JPL-built and managed SeaWinds instruments aboard Japan’s Midori 2, and NASA’s Quick Scatterometer (QuikScat) satellites can detect these winds before other instruments, providing even earlier notice of developing storms to forecasters and scientists.

Air temperature and humidity are also important factors. The JPL-managed Atmospheric Infrared Sounder experiment suite aboard the Aqua satellite obtains measurements of global temperature and humidity throughout the atmosphere. This may lead to improved weather forecasts, improved determination of cyclone intensity, location and tracks, and the severe weather associated with storms, such as damaging winds.

Rainfall intensity is the final ingredient, and the precipitation radar provided by Japan for the Tropical Rainfall Measuring Mission satellite provides computed tomography (CAT) scan-like views of rainfall in the massive thunderstorms of hurricanes. The mission’s instruments probe young tropical systems for rainfall intensity and the likelihood of storm development. The mission also sees “hot towers” or vertical columns of rapidly rising air that indicate very strong thunderstorms. These towers are like powerful pistons that convert energy from water vapor into a powerful wind- and rain-producing engine. Once a storm develops, the mission provides an inside view of how organized and tightly spiraled rain bands are, key indicators of storm intensity.

The Tropical Rainfall Measuring Mission provides tropical cyclone intensity information from the safe distance of space, allowing the National Oceanic and Atmospheric Administration’s National Hurricane Center and the Department of Defense Joint Typhoon Warning Center to turn to it, QuikScat and other NASA satellites for early assessment of storms in the open ocean.

The hurricane monitoring capabilities enabled by these satellites are funded by NASA’s Earth Science Enterprise, which is dedicated to understanding Earth as an integrated system and applying Earth system science to improve prediction of climate, weather and natural hazards using the unique vantage point of space.

Original Source: NASA/JPL News Release. Here are some hurricanes pictures.

Image credit: ESA

As the weather is starting to cool in Europe after a particularly hot summer, the European Space Agency snapped this picture of the continent with pretty much cloudless skies. The composite image was built up from a series of pictures snapped by the ESA’s Meteosat Second Generation 1 (MSG-1). The satellite was launched almost exactly a year ago and is positioned above Europe in geostationary orbit.

As most Europeans breathe a sigh of relief as this record-breaking summer draws to a close, the extreme weather conditions experienced in recent weeks have given us a rare view of an almost cloud-free Europe, taken by Europe?s weather satellite MSG-1, launched a year ago this week.

This enhanced composite image was taken on 10 August 2003, at midday (12:00 UT) and shows a virtually cloud-free Europe. Only the UK and Finland are partially obscured by cloud. Meteosat Second Generation 1 (MSG-1) is the first of a new generation of weather satellites, developed in close cooperation between the European Space Agency (ESA) and EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites.

Built by ESA and operated by EUMETSAT, MSG-1 was launched by Ariane, a year ago on 28 August at 22:45 UT, from Europe?s spaceport in French Guiana. MSG-1 is positioned in geostationary orbit, at 10.5?W 36 000 kilometres above the Earth. This image illustrates the excellent performance of the innovative radiometer carried by MSG-1.

The MSG system will provide an essential service for weather experts for at least the next 12 years. This continuity of service is important not only to make short-term forecasts, but also to investigate global weather trends in the longer term.

Original Source: ESA News Release

Image credit: NASA

NASA has released a new image of the entire Earth based on images taken during the Shuttle Radar Topography Mission. The global data set greatly improves maps of the Earth’s surface between 60-degrees North and South of the equator – 80% of the globe. Previous maps of the United States have a similar resolution as the SRTM30 data – about 1 km – but the rest of the world is often inaccurate. SRTM is capable of producing even higher-resolution maps, down to 30 metres.

A brand new look and understanding of the place we call home. That’s what you’ll get in a complete global topographic data set generated by NASA and the National Imagery and Mapping Agency (NIMA).

Produced by the Shuttle Radar Topography Mission, the global data set, called “SRTM30,” greatly improves maps of Earth’s land mass located between 60 degrees north and 60 degrees south of the equator. That’s roughly from the southern tip of Greenland to below the southern tip of South America.

Until now, the primary source of digital elevation data for scientists and analysts involved in global studies has been the U.S. Geological Survey’s “GTOPO30,” published in 1996, it consists of elevation measurements spaced every 30-arc-seconds. An arc-second is a measure of latitude and longitude used by geographers that corresponds to about 30.9 meters, or 101.4 feet, at the equator. This allows identification of features roughly the size of Disneyland in California. The SRTM30 map matches the GTOPO30 resolution, but with its seamless quality, the map represents a leap in global-scale accuracy.

“SRTM30 is a powerful demonstration of the benefits which accrue from NASA’s human space flight program and satellite radar mapping technology,” said John LaBrecque, manager, Solid Earth and Natural Hazards Program, NASA Headquarters, Washington.

“The quality of previous maps of the Earth varied considerably, because they were compiled from various data gathered by generations of explorers and surveyors. In some places these maps are inaccurate. Using NASA technology, six Space Shuttle astronauts mapped 80 percent of Earth’s land surface in just 10 days to produce the first 3-D map of the Earth’s surface at a known and uniform accuracy,” he said.

The need for accurate topographic maps is everywhere from planning a hike to building a new highway. Knowing the exact shape and location of mountain peaks and river valleys is as important to the safe and efficient flight of aircraft as it is to the management of water resources and the control of forest fires.

Newly released images, representing the new SRTM30 data products, depict Earth in two ways: as an image with all the continents shown (a common map-making method known as a Mercator projection); and as three globe images of Earth as viewed from points in space centered over the Americas, Africa and the western Pacific. Two visualization methods were combined to produce the images: shading and color-coding of topographic height. The shaded image was derived by computing topographic slope in the northwest-southeast direction, so northwest slopes appear bright and southeast slopes appear dark. Color-coding depicts the lowest elevations in green, rising through yellow and tan, to white at the highest elevations.

The SRTM30 map is one of a series of land surface products emerging from the very successful Shuttle Radar Topography Mission (SRTM). SRTM has produced more detailed topographic data for North and South America that resolves features approximately 90 feet square, or 10 times the global SRTM30 database.

The SRTM data were processed at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., into research-quality digital elevation data. NIMA is providing additional processing to develop official mapping products. The U.S. Geological Survey Earth Resources Observation Systems Data Center in Sioux Falls, S.D. provides final archiving and distribution of the SRTM data products.

The SRTM mission is a cooperative project of NASA, NIMA, German and Italian space agencies. The project is part of NASA’s mission to understand and protect our home planet.

The new images are available on the JPL Planetary Photojournal at:

http://photojournal.jpl.nasa.gov/catalog/PIA03394

http://photojournal.jpl.nasa.gov/catalog/PIA03395

http://photojournal.jpl.nasa.gov/catalog/PIA03396
Information about the Shuttle Radar Topography Mission is available at:

http://www.jpl.nasa.gov/srtm/

Original Source: NASA News Release

Image credit: NASA

New software developed at NASA’s Jet Propulsion Laboratory may give firefighters a new tool for spotting forest fires before they get a chance to really get going. The software will link various NASA Earth science satellites together into a virtual web of sensors. If one satellite spots a blaze, it can instruct the other satellites to take more detailed photographs of the area. Controllers can then report the fire to officials as well as scientists interested in how early forest fires behave. Similar software is being considered for other natural events, like floods.

If a forest catches fire and no one is around to see it, can it call for help? The forest cannot call, but thanks to new technology developed by NASA, firefighters may get the word faster through new, high-tech eyes in the sky.

New software developed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif., helps link NASA’s Earth science satellites together to form a virtual web of sensors with the ability to monitor the globe far better than individual satellites. An imaging instrument flying on one satellite can detect a fire or other hazard, and automatically instruct a different satellite that has the ability to take more detailed pictures to take a closer look. If the images show that a potential hazard does exist, the responding satellite provides data to ground controllers, who then report the fire to forest officials and to an interested science team.

“Essentially, we are adding the response mechanism to the detection process,” said Dr. Steve Chien, JPL principal scientist in artificial intelligence. “This is a first step to enabling users of satellite remote sensing data to specify the kind of data they want, such as forest fires or floods, rather than the traditional request to, say, look at northern Montana.”

One of the core components in this collaborative effort is the Science Goal Monitor system being developed at NASA’s Goddard Space Flight Center, Greenbelt, Md. The system enables scientists to specify what to look for and how to react in descriptive rather than technical terms. Then the system monitors science streams of data to identify occurrences of the key events previously specified by the scientist.

“When an event occurs, the system autonomously coordinates the execution of the scientist’s desired reactions between different observatories or satellites,” said Jeremy Jones, Goddard’s task leader for the monitor system. “This is designed to be adaptable to many different types of phenomena and supports a wide variety of sensor web configurations.”

Using the sensor web method, investigators no longer have to rely on after-the-fact data analysis to determine what happened. The information can be used to rapidly respond to hazardous events such as forest fires.

For example, moderate-resolution imaging instruments that fly on both NASA’s Terra and Aqua spacecraft observe the entire globe every day. The instruments’ data are automatically processed on the ground within hours of acquisition by the Rapid Response System at the Goddard Space Flight Center. If this processing detects a hot spot, scientific criteria can be used to automatically redirect the Earth Observing 1 satellite to provide high-resolution images. When that information comes back to a scientist for interpretation, it is made available to forest officials to determine the appropriate response. All this can happen in 24 to 48 hours, compared to a typical lead time of 14 days for preplanned observations.

The satellite sensor web demonstration is a collaborative effort between JPL and the Goddard Space Flight Center. The Rapid Response project is a joint Goddard Space Flight Center effort with the University of Maryland, College Park, led by Dr. Chris Justice.

Original Source: NASA/JPL News Release

The National Oceanic and Atmospheric Administration posted satellite images online that showed the extent of the power blackout that affected more than 50 million people late last week. The photos show the areas both before and after the lights went out and demonstrate the dramatic change in power. The images were acquired by the agency’s Defense Meteorological Satellite Program (DMSP) on August 14 at 9:03 pm EDT.

Image credit: ESA

China’s Three Gorges Dam was recently photographed from above by the European Space Agency’s CHRIS instrument on the Proba satellite. Since the sluice gates were closed in June, the water levels have risen 135 metres, and the dam will begin generating its first commercial electricity in August. More than 600,000 people were forced to abandon their homes, and the same number again will have to leave before the waters reach their planned 175 metre depth.

Water churns through diversion holes in the world?s largest dam – China?s Three Gorges project on the Yangtze River, imaged here by ESA?s Proba satellite this week. Seen to the left, the waters behind the dam have risen to a level of 135 metres since the sluice gates were first closed in early June, and in August Three Gorges is due to generate its first commercial hydroelectricity.

The Three Gorges project is set to create a new 600-km-long body of water on the face of the 21st century Earth: the thick concrete dam walls stand 190 metres tall and already they hold back an estimated 10 billion cubic metres of water. More than 600,000 people have had to abandon their homes to the rising reservoir, and as many again will have to relocate before the waters reach their final planned level of 175 metres.

Water flows through dam diversion holes
It can be clearly seen in the image how the river has burst its banks and is inundating the land upriver of the dam. The waters of the world?s third-longest river appear brown in colour because they are heavy with sediment.

Many environmentalists have campaigned against the ?20 billion-plus Three Gorges project due to the drowning of multiple cultural heritage sites, the fear that reservoir will collect industrial pollution and sewage that cannot now be washed to the sea, and the risk posed to downstream populations if the dam should ever break. But the Chinese government says the project will tame the flood-prone Yangtze River and generate much-needed electricity for economic development.

This 18-metre resolution image was acquired by the CHRIS sensor onboard Proba on 30 July 2003.

About Proba
Proba (Project for On Board Autonomy) is a micro-satellite the size of a small box, launched by ESA in October 2001 and operated from ESA’s Redu Ground Station (Belgium). Orbiting 600 km above the Earth?s surface, Proba was designed to be a one-year technology demonstration mission but has since had its lifetime extended as an Earth Observation mission. It now routinely provides scientists with detailed environmental images thanks to CHRIS – a Compact High Resolution Imaging Spectrometer developed by UK-based Sira Electro-Optics Ltd – the main payload on the 100 kg spacecraft.

Proba boasts an ?intelligent? payload, has the ability to observe the same spot on Earth from a number of different angles and can record images of an 18.6 km square area to a resolution of 18 m. More than 60 scientific teams across Europe are making use of Proba data. A follow-on mission, Proba-2, is due to be deployed by ESA around 2005.

Original Source: ESA News Release