Norwegian Fringes

The animation, which is based on an interferogram generated with two radar images captured by Sentinel-1A in ‘Interferometric Wide-Swath’ mode on 11 and 23 August 2014, mainly shows topography around the northern coast of Norway. Although Sentinel-1A is still being commissioned, this new result demonstrates how useful it will be to map the shape of the land and monitor ground movement. Synthetic aperture radar interferometry – or InSAR – is a technique where two or more satellite radar images acquired over the same area are combined to map topography and detect surface changes. Small changes on the ground cause changes in the radar signal phase and lead to the rainbow-colored fringes of an ‘interferogram’. In this case, the animation denotes differences in topography.

Since the area around the Lyngen Alps is particularly prone to landslides, it is closely monitored. Large landslides that suddenly shift rock into the sea could potentially create tsunami-like waves. In 1810, such a wave destroyed a village, and, history shows that this kind of natural disaster occurs a couple of times every 100 years in Norway. InSAR is an important tool used by the Norwegian authorities to map rockslide hazards nationwide. The unprecedented coverage offered by the Sentinel-1 mission will significantly increase the value of InSAR data for this purpose.

Video credit: Copernicus data (2014)/ESA/Norut–SEOM Insarap study (video animation data: Norwegian Mapping Authority and NASA)

Note: For more information, see Norway Relief. For similar images, one featuring northwestern Italy and part of Corsica and the other featuring Mount Etna on the island of Sicily, see New Views From Sentinel-1A and Etna Slopes, respectively.

Unexpected Teleconnections in Noctilucent Clouds

Earth's poles are separated by four oceans, six continents and more than 12,000 nautical miles.

Turns out, that's not so far apart.

New data from NASA's AIM spacecraft have revealed "teleconnections" in Earth's atmosphere that stretch all the way from the North Pole to the South Pole and back again, linking weather and climate more closely than simple geography would suggest.

For example, says Cora Randall, AIM science team member and Chair of the Department of Atmospheric and Oceanic Sciences at the University of Colorado, "we have found that the winter air temperature in Indianapolis, Indiana, is well correlated with the frequency of noctilucent clouds over Antarctica."

Noctilucent clouds, or "NLCs," are Earth's highest clouds. They form at the edge of space 83 km above our planet's polar regions in a layer of the atmosphere called the mesosphere. Seeded by "meteor smoke," NLCs are made of tiny ice crystals that glow electric blue when sunlight lances through their cloud-tops.

AIM was launched in 2007 to investigate these "night-shining" clouds, to discover how they form and to learn about their inner chemistry. As is often the case, however, when exploring the unknown, researchers found something they weren't even looking for: teleconnections.

"It has been a surprise," says Hampton University professor of atmospheric and planetary science James Russell, Principal Investigator of the AIM mission. "Years ago when we were planning the AIM mission, our attention was focused on a narrow layer of the atmosphere where NLCs form. Now we are finding out this layer manifests evidence of long-distance connections in the atmosphere far from the NLCs themselves."

One of these teleconnections links the Arctic stratosphere with the Antarctic mesosphere.

"Stratospheric winds over the Arctic control circulation in the mesosphere," explains Randall. "When northern stratospheric winds slow down, a ripple effect around the globe causes the southern mesosphere to become warmer and drier, leading to fewer NLCs. When northern winds pick up again, the southern mesosphere becomes colder and wetter, and the NLCs return."

This January, a time of year when southern NLCs are usually abundant, the AIM spacecraft observed a sudden and unexpected decline in the clouds. Interestingly, about two weeks earlier, winds in the Arctic stratosphere were strongly perturbed, leading to a distorted polar vortex.

"We believe that this triggered a ripple effect that led to a decline in noctilucent clouds half-way around the world," says Laura Holt of the University of Colorado's Laboratory for Atmospheric and Space Physics. "This is the same polar vortex that made headlines this winter when parts of the USA experienced crippling cold and ice."

Holt took a careful look at meteorological data and found that, indeed, there was a statistical link between winter weather in the USA and the decline in noctilucent clouds over Antarctica.

"We picked Indianapolis as an example, because I have family living there," says Randall, "but the same was true of many northern cities: cold air temperatures on the ground were correlated with NLC frequencies high above Antarctica two weeks later," she says.

The two week delay is, apparently, how much time it takes for the teleconnection signal to propagate through three layers of atmosphere (the troposphere, stratosphere and mesosphere), and from pole to pole.

It is a complicated topic, but this much is clear: "NLCs are a valuable resource for studying long-distance connections in the atmosphere," says Russell, "and we are just getting started."

Video credit: NASA

Liftoff of Sentinel-1A

Cameras mounted on the Soyuz Fregat upper stage that sent Sentinel-1A into space on 3 April 2014 captured this footage from liftoff to separation.

The 2.3-ton satellite lifted off on a Soyuz rocket from Europe’s Spaceport in Kourou, French Guiana at 21:02 GMT (23:02 CEST). The first stage separated 118 sec later, followed by the fairing (209 sec), stage 2 (287 sec) and the upper assembly (526 sec). After a 617 sec burn, the Fregat upper stage delivered Sentinel into a Sun-synchronous orbit at 693 km altitude. The satellite separated from the upper stage 23 min 24 sec after liftoff.

Sentinel-1 is the first in the family of satellites for Europe’s Copernicus program. It carries an advanced radar to scan Earth’s surface in all weather conditions and regardless of whether it is day or night. This new mission will be used to care for many aspects of our environment, from detecting and tracking oil spills and mapping sea ice to monitoring movement in land surfaces and mapping changes in the way land is used.

Video credit: Arianespace/ESA/Roscosmos; Music written by M. Oldfield/copyright EMI Virgin

Update: A slightly longer version of the video can be found here: Onboard Cameras Show Full Launch and Separation of Sentinel-1A.

Arctic Melt Season Lengthens

A new study by researchers from the National Snow and Ice Data Center (NSIDC) and NASA shows that the length of the melt season for Arctic sea ice is growing by several days each decade. An earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation in some places to melt as much as four feet of the Arctic ice cap’s thickness.

"The Arctic is warming and this is causing the melt season to last longer," said Julienne Stroeve, a senior scientist at NSIDC, Boulder and lead author of the new study, which has been accepted for publication in Geophysical Research Letters. "The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the ocean and increase ice melt during the summer, overall weakening the sea ice cover."

Arctic sea ice has been in sharp decline during the last four decades. The sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. The seven lowest September sea ice extents in the satellite record have all occurred in the past seven years.

To study the evolution of sea ice melt onset and freeze-up dates from 1979 to the present day, Stroeve’s team used passive microwave data from NASA’s Nimbus-7 Scanning Multichannel Microwave Radiometer, and the Special Sensor Microwave/Imager and the Special Sensor Microwave Imager and Sounder carried on board Defense Meteorological Satellite Program spacecraft. When ice and snow begin to melt, the presence of water causes spikes in the microwave radiation that the snow grains emit, which these sensors can detect.

Results show that although the melt season is lengthening at both ends, with an earlier melt onset in the spring and a later freeze-up in the fall, the predominant phenomenon extending the melting is the later start of the freeze season. Some areas, such as the Beaufort and Chukchi Seas, are freezing up between six and 11 days later per decade. Although melt onset variations are smaller, the timing of the beginning of the melt season has a larger impact on the amount of solar radiation absorbed by the ocean, because its timing coincides with when the sun is higher and brighter in the Arctic sky.

Despite large regional variations in the beginning and end of the melt season, the Arctic melt season has lengthened on average by five days per decade from 1979 to 2013.

Video credit: NASA

Ice Sheet Contribution to Sea-Level Rise

This animation merges 20 years of satellite data to demonstrate how much – and how fast – the ice sheets cover Greenland and Antarctica are melting and their contribution to sea-level rise.

Video credit: Planetary Visions

Rapid Mapping of European Floods

Floods across central Europe caused widespread damage in 2013. Maps based on satellite data can help emergency services plan their response to such events. Through the Copernicus Emergency Management Service, 118 maps were produced to assist in flood relief.

Video credit: ESA/DLR

Note: For more information, see Flood Mapping Highlight.

Monitoring Alaskan Lake Ice

In northern Alaska, within the Arctic circle, the ice regimes of shallow lakes were documented using 79 radar images from the ERS-1 and -2 satellites. How the radar signals bounced back to the sensor indicated ‘floating ice’ versus ‘grounded ice’ (fully frozen lake) when radar energy was absorbed into the ground. The data showed that from 1992 to 2011 the lakes in this region experienced a 22% reduction in grounded ice – the equivalent of ice thinning by 21–38 cm.

Video credit: Planetary Visions / University of Waterloo, Canada / ESA

1993–2011 Ocean Currents

Weekly evolution of ocean surface currents from January 1993 to December 2011. Strong currents such as the Gulf Stream in the Atlantic Ocean, the Kuroshio in the Pacific Ocean and the Agulhas Current along the east coast of Africa are visible. The Antarctic Circumpolar Current and Equatorial currents are also evident, with speeds reaching up to 1.5 m/s. Gravity data from the GOCE mission together with 20 years of satellite altimetry measurements and information from drifters were combined to create this animation of our moving oceans.

Video credit: ESA/CNES/CLS

Greenland's Hidden Grand Canyon

Hidden for all of human history, a 460 mile long canyon has been discovered below Greenland's ice sheet. Using radar data from NASA's Operation IceBridge and other airborne campaigns, scientists led by a team from the University of Bristol found the canyon runs from near the center of the island northward to the fjord of the Petermann Glacier.

A large portion of the data was collected by IceBridge from 2009 through 2012. One of the mission's scientific instruments, the Multichannel Coherent Radar Depth Sounder, operated by the Center for the Remote Sensing of Ice Sheets at the University of Kansas, can see through vast layers of ice to measure its thickness and the shape of bedrock below.

Video credit: NASA

Note: For more information, see Mega-Canyon Discovered Beneath Greenland Ice.

The Spread of Western Wildfire Pollution

A new movie produced with data from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft shows the spread of carbon monoxide pollution across North America from fires in the Western U.S., including the Beaver Creek Fire in Idaho and the Rim Fire in California. The movie shows carbon monoxide concentrations at altitude 18,000 feet (5.5 kilometers) as measured by AIRS.

About AIRS
The Atmospheric Infrared Sounder, AIRS, in conjunction with the Advanced Microwave Sounding Unit, AMSU, senses emitted infrared and microwave radiation from Earth to provide a three-dimensional look at Earth's weather and climate. Working in tandem, the two instruments make simultaneous observations all the way down to Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, three-dimensional map of atmospheric temperature and humidity, cloud amounts and heights, greenhouse gas concentrations, and many other atmospheric phenomena. Launched into Earth orbit in 2002, the AIRS and AMSU instruments fly onboard NASA's Aqua spacecraft and are managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

Video credit: NASA/JPL-Caltech

Disaster Management from Space

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Floods are usually accompanied by cloudy skies making it difficult to monitor them from space. Using radar technology, the new GMES Sentinel-1 satellite is able to 'see' through clouds and rainfall to map emergency-stricken regions.

Video credit: ESA/DLR

Japan Earthquake Sensed by GOCE

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New studies have revealed that the massive earthquake that hit Japan on 11 March 2011 was also felt in space by ESA’s GOCE satellite. The massive earthquake sent ripples of sound – called infrasound – upwards through the atmosphere. These sound waves caused changes in air density that were detected by ESA’s GOCE gravity satellite as it crossed the wavefront.

Read full article: GOCE the First Seismometer in Orbit.

Video credit: ESA/IRAP/CNES/TU Delft/HTG/Planetary Visions

Japanese Earthquake Sensed from Space

The animation shows how the massive earthquake that hit Japan in 2011 caused ripples in the atmosphere. As sound waves from the earthquake traveled upwards, they caused changes in air density that were detected by ESA’s GOCE gravity satellite as it crossed the wavefront.

Video credit: ESA/IRAP/CNES/TU Delft/HTG/Planetary Visions

Monthly Sea Ice Volume

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Time-series of monthly Arctic sea ice volume from CryoSat (red circles) and from PIOMAS (solid line) for two winter growth periods (October – April).

The new CryoSat data provide further evidence of the long-term decreases in Arctic sea ice volume simulated by the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS), which estimates the volume of Arctic sea ice using data from submarine, mooring and satellite observations. However, the rate of decline in autumn ice volume measured by CryoSat is 60% higher than the decline in PIOMAS analyses, but 25% lower in winter.

Video credit: CPOM/UCL/ESA/UW-APL/NSIDC/Planetary Visions

Note: For more information, see Study Sheds New Light on Arctic Sea Ice Volume Losses.

African Equatorial Forest

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The animation shows the change in vegetation in African equatorial forest from 12 months of data from Spot’s Vegetation instrument. The area includes Congo, DR of Congo, Gabon, Equatorial Guinea and Cameroon.

Video credit: CNES/VITO

Note: For some reason, the Venice Land Subsidence video sometimes appears in place of the proper video. Click on the title to see the individual post, and the appropriate video should then appear.

Antarctic Ozone Holes: 2011 and 2012

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Ozone distribution over the South Pole from July to December during the years 2011 (left) and 2012 (right).

The 2012 ozone hole duration, geographical extension and depth was much smaller than that of 2011. Ozone loss over the South Pole is displayed at the bottom (the bold dark line indicates the ozone loss for 2012 and the grey line for 2011). The ozone maps were generated by the assimilation of GOME-2 total ozone data into the model TM3DAM. GOME-2 is carried by Eumetsat’s MetOp mission.

Video credit: KNMI

Arctic Sea Ice: 1978-2010

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Time series of Arctic sea ice concentration in September from 1978 to 2010.

Video credit: ESA/DLR

Arctic Ocean Ice Decrease, 1979-2010

This animation shows Arctic ice cover from 1978 to 2010. The past five years have seen the lowest Arctic sea-ice extent since satellite measurements began in the 1970s.

Video credit: ESA/DLR

Deforestation of the Amazon Rain Forest

This animation shows deforestation of the Amazon Rainforest in the western Brazilian state of Rondônia from 1986 to 2010. While the central area remains green and untouched, squares of light green and brown pop up over time as the forest is cut away.

The animation was created using two cloud-free images: the first from NASA’s Landsat mission in 1986, and the second from the Spanish Deimos mission in 2010. The changes over time were simulated by referring to other satellite data acquired during the 24 years between the two images.

Video credit: ESA/USGS/Deimos Imaging; text credit: ESA/USGS/Deimos Imaging

Ground Deformation at the Nea Kameni Volcano

Evolution of ground deformation over Nea Kameni Volcano (Santorini, Greece) from March 2011 to February 2012. The animation was derived using data from Differential Interferometric Synthetic Aperture Radar analysis of Envisat’s radar data.

Video credit: ESA

Note: This particular island is famous for the volcanic eruption that destroyed the Minoan civilization living on the island of Thera, as Santorini was known at the time. The artwork that was preserved by the eruption is very beautiful.