Earth Observation Archives

January 15, 2010April 26, 2016 by Nicholos Wethington

India Launched 11 Rockets to Monitor Eclipse

India launched a small fleet of rockets to monitor the effects of the annular solar eclipse that occurred today. A total of 11 Rohini sounding rockets – suborbital rockets designed for scientific experiments – were launched from several different sites, including the Satish Dhawan Space Centre (SDSC) in Sriharikota. These rockets, launched by the Indian Space Research Organization (ISRO), carried instruments to measure the effect the eclipse had on the Earth’s atmosphere.

The eclipse – which lasted 11 minutes and 8 seconds at its peak, was visible to observers in Africa, southern Asian countries, India and China. This was an annular eclipse, meaning that the Moon blocked the Sun’s light enough for a bright ring to be seen around the silhouette of the Moon, and was the longest such eclipse of the millennium.

There are several phenomena that take place in the lessening of the Sun’s rays during an eclipse. When the solar radiation drops during an eclipse, the ionization that occurs in the atmosphere is temporarily lowered, causing disruptions in the Equatorial Electrojet – a ribbon of electric current that flows east to west near the equator.

The temperature and wind of the atmosphere are also altered by the cessation of sunlight, and were measured by the rockets. India launched five rockets yesterday to record pre-eclipse data, and then six more were launched today to measure the changes after the eclipse, which peaked at 1:15pm local time. Over 90% of the Sun’s light was blocked near the Thumba Equatorial Rocket Launching Station (TERLS), which lies on the southern tip of India, and was well-placed to measure the eclipse.

“Results of these experiments will coordinate ground-based eclipse observations with in situ space measurements. Interpretation of eclipse data together with space data is expected to give new insights to the earlier eclipse observations,” the ISRO wrote in a press release.

Sounding rockets have been used by other space agencies to monitor the ionosphere and the role of the Sun in atmospheric phenomenon. In 1994, NASA cooperated with Brazil on the Guara Campaign, named after the Guara bird that is native to Brazil. In August-October of that year, NASA launched a total of 33 rockets with various experiments to measure the photochemistry and plasma of the atmosphere near the equator. All of the rockets were launched from the Alcantara launch range in Brazil.

Source: ISRO press release

January 14, 2010December 24, 2015 by Nancy Atkinson

Latest GeoEye Satellite Imagery of Haiti Devastation Now Available on Google Earth

Before-and-after screenshots of the Presidential Palace and an area of Port-au-Prince. Credit: Google, GeoEye

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The folks at Google Earth and the satellite imaging company GeoEye have teamed up to make available the most recent Haiti photos — taken at approximately 10:27am EST on January 13, 2010. It is available as a KML overlay for Google Earth, and you can download the KML here and open it in Google Earth. You can also open the file in Google Maps. As you’ll see, the imagery shows a powerful glimpse into the destruction in Haiti. Above are before-and-after screenshots of the Presidential Palace and an area of Port-au-Prince.

Google said they will continue to automatically update the layer (you’ll only need to download it once) to make more imagery and data available.

If you don’t have Google Earth (what!) you can go to this page and see the images in an embedded KML viewer.

Google also has a listing of how you can help the relief efforts in Haiti.

Source: Google Lat Long Blog

January 13, 2010December 24, 2015 by Nancy Atkinson

Maps of Earthquake and Aftershocks in Haiti

Caption: NASA Earth Observatory image by Jesse Allen

At 21:53 UTC on January 12, 2010 an earthquake with a magnitude 7.0 struck the Caribbean nation of Haiti. The US Geological Survey (USGS) says that it was the most violent earthquake to strike the impoverished country in a century, and death tolls are reported to be rising into the hundreds of thousands. “Porte-au-Prince is probably one of the worst constructed cities in the world, and even the presidential palace collapsed,” said Roger Bilham, from the University of Colorado-Boulder. “This is an earthquake many of us were expecting to occur sooner or later.”

Map of earthquake and aftershocks in Haiti. Credit: USGS

This image from the USGS shows all the seismic activity in the region, including areas in the ocean.

Dennis Mileti, also from CU-Boulder said three factors contributed to the severity of the Haitian event: the shallow location of the earth quake (only 8.3 kilometers or 5.2 miles underground) resulting in high shaking intensity; the low-quality construction of structures in the area; and the lack of earthquake preparedness and increased vulnerability resulting from Haiti being a poor country.

The epicenter of the earthquake was just 15 kilometers (10 miles) southwest of the Haitian capital of Port-au-Prince. Besides its strong magnitude, the earthquake’s shallow depth ensured that the densely populated capital would suffer violent shaking. More than 30 aftershocks rocked the area.

Reports say a majority if the infrastructure has collapsed, including schools, hospitals, government buildings – such as the presidential palace and the main prison — aid centers, and shantytowns.

The top map shows the region surrounding the 7.0-magnitude earthquake and the aftershock. Earthquake magnitudes are measures of earthquake size calculated from ground motion recorded on seismographs.

Ocean areas appear in shades of blue, and land areas appear in shades of brown. Both in water and on land, higher elevation appears in lighter colors. Black circles mark earthquake locations determined by the USGS, and circle sizes correspond with quake magnitudes. Black lines indicate fault lines.

The map was created using earthquake and plate tectonics data from the USGS Earthquake Hazard Program, elevation data from the Shuttle Radar Topography Mission (SRTM) courtesy of the University of Maryland’s Global Land Cover Facility, and ocean bathymetry data from the British Oceanogprahic Data Centre’s (BODC) General Bathymetric Chart of the Oceans (GEBCO).

This “shake” map from the USGS shows the intensity of shaking felt across the region in Haiti.

The USGS said the earthquakes occurred along the boundary between the Caribbean and North America plates. This area is characterized as a strike-slip fault where the Caribbean plate moves eastward with respect to the North America plate.

But Haiti wasn’t the only place an earthquake has taken place recently. Check out this intriguing map of earthquakes in the past week.

Sources: NASA Earth Observatory, USGS, University of Colorado-Boulder, Nature,

January 7, 2010December 24, 2015 by Nancy Atkinson

UK’s Big Snowfall, As Seen From Space

Great Britain, as seen on Jan. 7, 2010 by the Terra Satellies. Credit: NASA

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This satellite image taken by NASA’s Terra satellite shows the entire island of Great Britain blanketed by heavy snowfall, with some areas seeing the most snow in 50 years. It looks pretty from space, but frigid temperatures followed snowfall, leaving roads and sidewalks treacherously icy, according to news reports. As of January 7, overnight temperatures had plunged to -18 degrees Celsius (-0.4 degrees Fahrenheit) in isolated spots, with more widespread temperatures of -10 degrees Celsius (14 degrees Fahrenheit). The heavy snowfall downed power lines, leaving several thousand homes in southern England without electricity.

North America is also experiencing heavy snows and cold temperatures. NASA’s Earth Observatory website says that a possible contributor to the persistent cold and snow across much of the Northern Hemisphere’s mid-latitudes in December 2009 and January 2010 could be the fact that the atmosphere was in an extreme negative phase of the Arctic Oscillation (AO). The AO is a seesawing strengthening and weakening of semi-permanent areas of low and high atmospheric pressure in the Arctic and the mid-latitudes. One consequence of the oscillation’s negative phase is cold, snowy weather in Eurasia and North America during the winter months. The extreme negative dip of the Arctic Oscillation Index in December 2009 was the lowest monthly value observed for the past six decades.

Source: Earth Observatory

December 30, 2009December 24, 2015 by Nancy Atkinson

Mayon Volcano Threatens Major Eruption

Satellite image of Mayon Volcano in the Phillipines from Dec. 28, 2009.

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Mayon Volcano, on the Philippine island of Luzon, has been exhibiting activity suggesting a major eruption is imminent. Described as an “intense level of unrest” by the Philippine Institute of Volcanology and Seismology, Mayon exhibited 7 ash explosions, dozens of earthquakes related to the movement of magma beneath the volcano, over 100 rock falls from the summit, and 3 active lava flows. The Philippine government is enforcing evacuations in a danger zone extending 7 kilometers (4 miles) north and 8 kilometers (5 miles) south of the summit. Tens of thousands of people living within the danger zone (up to 8 kilometers away) of Mayon Volcano in the Philippines were forced to evacuate to emergency shelters in mid-December 2009.

The satellite image above shows Mayon emitting a thin volcanic plume on Dec. 28. Ash obscures the summit crater and clouds hide lava flows on the volcano’s flanks. The natural-color image was acquired by the Advanced Land Imager (ALI) aboard the NASA Earth Observing-1 (EO-1) satellite.

Below, the image from Dec. 15 shows how close a major populated area is to the volcano.

The volcano has been noticeably active for several weeks, and officials say “magma is close to the crater and hazardous explosive eruption is imminent.”

Source: NASA Earth Observatory

December 21, 2009December 24, 2015 by Nancy Atkinson

Record Setting US Snowstorm as Seen From Space

A record-setting snowstorm that blanketed the US Atlantic coast snarled both road and air traffic as holiday travelers and shoppers were forced to stay home. In all, the National Climatic Data Center (NCDC) reported 66 daily snow records in the northeastern United States were tied or broken over the weekend. Additionally, 21 monthly snow total records were tied or broken. Snowfall totals from 30 – 60 cm (1 to 2 feet) were commonplace.

This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite shows the Chesapeake Bay area cloaked in white on December 21, 2009, the first day of northern hemisphere winter. The winter solstice occurred Monday at 16:47 GMT (11:47 am EST). Learn more about the solstice on today’s 365 Days of Astronomy podcast, “December Solstice, Celebrating the Light” by Dr. Judith Young.

The image above encompasses about 480 km (300 miles) lengthwise. The two big rivers near the center are the Susquehanna (north) and Potomac rivers, which flow into the Chesapeake Bay. Washington, D.C., sits alongside the Potomac, just north of the river’s hook-shaped curve. The inlet to the north is Delaware Bay.

Source: NASA’s Earth Observatory

December 17, 2009December 24, 2015 by Nancy Atkinson

Earth’s Upper Atmosphere is Cooling

New measurements from a NASA satellite show a dramatic cooling in the upper atmosphere that correlates with the declining activity of the current solar cycle. For the first time, researchers can show a timely link between the Sun and the climate of Earth’s thermosphere, the region above 100 km, an essential step in making accurate predictions of climate change in the high atmosphere. This finding also correlates with a fundamental prediction of climate change theory that says the upper atmosphere will cool in response to increasing carbon dioxide.

Earth’s thermosphere and mesosphere have been the least explored regions of the atmosphere, in fact some have called it the “ignorosphere.” The NASA Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission was developed to explore the Earth’s atmosphere above 60 km altitude and was launched in December 2001. One of four instruments on the TIMED mission, the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, was specifically designed to measure the energy budget of the mesosphere and lower thermosphere. The SABER dataset now covers eight years of data and has already provided some basic insight into the heat budget of the thermosphere on a variety of timescales.

The extent of current solar minimum conditions has created a unique situation for recent SABER datasets. The end of solar cycle 23 has offered an opportunity to study the radiative cooling in the thermosphere under exceptionally quiescent conditions.

“The Sun is in a very unusual period,” said Marty Mlynczak, SABER associate principal investigator and senior research scientist at NASA Langley. “The Earth’s thermosphere is responding remarkably — up to an order of magnitude decrease in infrared emission/radiative cooling by some molecules.”

The TIMED measurements show a decrease in the amount of ultraviolet radiation emitted by the Sun. In addition, the amount of infrared radiation emitted from the upper atmosphere by nitric oxide molecules has decreased by nearly a factor of 10 since early 2002. These observations imply that the upper atmosphere has cooled substantially since then. The research team expects the atmosphere to heat up again as solar activity starts to pick up in the next year.

While this warming has no implications for climate change in the troposphere, a fundamental prediction of climate change theory is that the upper atmosphere will cool in response to increasing carbon dioxide. Emissions of carbon dioxide may warm the lower atmosphere, but they cool the upper atmosphere, because of the density of the atmospheric layer.

As the atmosphere cools the density will increase, which ultimately may impact satellite operations through increased drag over time.

The SABER dataset is the first global, long-term, and continuous record of the Nitric oxide (NO) and Carbon dioxide (CO2) emissions from the thermosphere.

“We suggest that the dataset of radiative cooling of the thermosphere by NO and CO2 constitutes a first climate data record for the thermosphere,” says Mlynczak.

The TIMED data provide a fundamental climate data record for validation of upper atmosphere climate models which is an essential step in making accurate predictions of climate change in the high atmosphere. SABER provides the first long-term measurements of natural variability in key terms of the upper atmosphere climate. As the TIMED mission continues, these data derived from SABER will become important in assessing long term changes due to the increase of carbon dioxide in the atmosphere.

The findings were presented at the American Geophysical Union fall meeting in San Francisco.

Source: NASA Langley

December 16, 2009December 24, 2015 by Nancy Atkinson

Giant Iceberg Still Heading for Australia (Satellite Images)

Iceberg B17-B Adrift Off the Southwestern Coast of Australia as seen on Dec. 11, 2009. Credit: NASA Earth Observatory

A city-sized iceberg that has been making its way towards Australia’s southwestern coast is now breaking up into hundreds of smaller icebergs as it drifts into warmer waters. This is creating potentially hazardous conditions for ships trying to navigate the region. The iceberg, known as B17B, was spotted last week on satellite imaging about 1,100 miles (1,700 kilometers) off Western Australia state, prompting Australia’s Bureau of Meteorology to issue a shipping alert. When first observed, B17B was a whopping 140 square kilometers (54 square miles). Now, it is about 115 square kilometers (44 square miles), or around 18 kilometers (11 miles) long and 8 kilometers (5 miles) wide, said glaciologist Neal Young of the Australian Antarctic Division. Still, that is one huge iceberg.

Iceberg B17-B Adrift Off the Southwestern Coast of Australia as seen on Nov. 29, 2009. Credit: NASA Earth Observatory

B17B has broken up into hundreds of smaller icebergs, some up to several kilometers wide, and spread over more than 1,000 kilometers of ocean. Young said he expects it to dissipate, but is unsure when that will happen.

The iceberg is one of several that split off in Antarctica in 2000 when parts of two major ice shelves — the Ross Sea Ice Shelf and Ronne Ice Shelf — fractured.

Icebergs frequently split or “calve” off Antarctica’s ice shelves, and they often get swept up in strong circumpolar currents that carry them around the icy continent. Occasionally icebergs drift northward, out of the continent’s orbit. Only rarely, however, do icebergs drift as far north as Australia without melting, which is why scientists were surprised to spot this especially gigantic iceberg in its current location.

Sources: NASA Earth Observatory, AP

Here are some cool iceberg pictures.

November 18, 2009April 26, 2016 by Nancy Atkinson

Get a $36 Million World Map for Free

When the first Landsat Earth-observing satellite launched in 1972, virtually every piece of technology that we think of as essential for viewing, sharing, or analyzing digital images — like the internet or DVD’s — either hadn’t been invented or commercialized, like the microprocessors that run desktop computers. “It cost about $4,000 for a single Landsat image, and it takes about 9,000 of them to map the land area of the globe,” said Jeff Masek, from NASA. “To make a global image for just one time period would have cost $36 million.” But now, in this age where everything is digital and it’s easy to exchange information, anyone can download Landsat images for free. Recently, NASA and the U.S. Geological Survey put the finishing touches on a new collection of mapped images covering the entire land surface of the Earth. However, if you want the entire full-size version, it would be as big as the Hoover Dam.

This collaboration between NASA, the U.S. Geological Survey, and the U.S. National Geospatial Agency, the Global Land Survey 2005 features around 9,500 images from NASA’s Landsat satellites captured between 2004–2007.

The images are detailed enough to make out features as small as 30 meters (about one-third the length of an American football field), they have been carefully screened for clouds, and each one shows the landscape during its growing season.

Some of the images are as striking as a piece of artwork. Stitched together into a single mosaic, the collection paints the most detailed picture of Earth’s land surface a person can get for free.

For more information see these two Landsat sites:

http://landsat.gsfc.nasa.gov/

http://www.landsat.org/

Source: NASA Earth Observatory

November 12, 2009December 24, 2015 by Nancy Atkinson

Crescent Earth as Seen by Comet Chasing Spacecraft

Earth as seen by the Osiris camera on Rosetta. Credit: ESA

Title this one “Rich Blue Crescent” (as opposed to Pale Blue Dot.) This spectacular image of our home planet was captured by the OSIRIS instrument on ESA’s Rosetta comet chaser today (November 12) at 12:28 GMT from about 633,000 km as the spacecraft approached Earth for the third and final swingby. Closest approach is due at 07:45 GMT, on November 13. You can follow Rosetta’s progress at ESA’s Rosetta site and the Rosetta Blog.