Category Archives: Earth Observatories

Proba’s Looks at Pyramids

This beautiful look at the Egyptian pyramids is courtesy of the Proba-1 satellite and ESA.

ESA — A view looking north to south of Egypt’s famous Giza Pyramid Complex, as seen by ESA’s Proba-1 minisatellite.

The smaller Pyramid of Menkaure is seen to towards the centre of the image, with the larger Pyramid of Khafre down and left of it, with the Great Pyramid of Giza – the largest and oldest of the three – below and left of that.

Three smaller pyramids are adjacent to the Pyramid Menkaure. The Giza Plateau sits on the edge of Cairo, fringed by suburbs.

The cubic-metre Proba-1 is the first in ESA’s series of satellites aimed at flight-testing new space technologies. It was launched on 22 October 2001 but is still going strong, having recently became the Agency’s longest-serving Earth-observing mission.

Proba-1’s main hyperspectral CHRIS imager is supplemented by this experimental High-Resolution Camera, acquiring black and white 5 m-resolution images.

Other innovations include what were then novel gallium-arsenide solar cells, the use of startrackers for gyroless attitude control, one of the first lithium-ion batteries – now the longest such item operating in orbit – and one of ESA’s first ERC32 microprocessors to run Proba-1’s agile computer.

For more background on Proba-1, read this celebration in the ESA Bulletin.

Proba-1 led the way for the Sun-monitoring Proba-2 in 2009, the vegetation-tracking Proba-V in 2013 and the Proba-3 precise formation-flying mission planned for late 2020.

This image was acquired on 6 January 2018.

Sahara Snow

Great look at the Sahara snows. Turns out snow in the Sahara while rare, is not unheard of.

NASA — For the second time in three years, snow has accumulated in the desert near the northern Algerian town of Aïn Séfra. Sometimes called the “gateway to the desert,” the town of 35,000 people sits between the Sahara and the Atlas Mountains. On January 8, Landsat 8 captured data for these natural-color images of the snow in the Sahara. The Landsat 8 image was draped over a global digital elevation model, built from data acquired by NASA’s Shuttle Radar Topography Mission.

According to news and social media accounts, anywhere from 10 to 30 centimeters (4 to 12 inches) of snow accumulated on January 8, 2018, on some higher desert elevations (1000 meters or more above sea level). Social media photos showed citizens sliding down snow-covered sand dunes. Warming temperatures melted much of it within a day.

Snow in the Sahara and other parts of North Africa is infrequent, but not unprecedented. Measurable snow fell near Aïn Séfra in December 2016. Substantial snow also blanketed the Atlas Mountains in Morocco in February 2012 and January 2005.

Image Credits: NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey and topographic data from the Shuttle Radar Topography Mission

Terra Looks at Isle of Eigg

Here’s a nice look at the beautiful Isle of Eigg Scotland from the Terra satellite.

Original caption: The island of Eigg is one of the small isles in the Scottish Inner Hebrides, south of the Skye peninsula. The main settlement of the 31 km2 island is Cleadale. In 2008, Eigg began a project to become completely energy self-sufficient. Using a combination of wind, water and solar, the population of about 90 now has 24-hour power. The image was acquired 18 September 2015, covers an area of 9.2 by 10.8 km, and is located at 57 degrees north, 6.2 degrees west.

With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan’s Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

The U.S. science team is located at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA’s Science Mission Directorate, Washington, D.C.

Credit: NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team

Landsat Look at B-44

You may remember the news of the huge ice berg that calved a few months ago in Antarctica called B-44. Now thanks to the southern sun and the Landsat 8 satellite we get a look at the area.

The polyna, although not the same reminded me of a phenomenon sometimes seen in larger freshwater lakes which is an internal seiche. A friend of mine ran a fish factory and had to deal with a seiche. Unlike what you may think of as a fish farm or fish hatchery you may visit and enjoy, this place was and is exactly like an industrial factory and is an all around horrible place. My friend only could take working there a short time and has moved on, but I do remember the headaches that seiche would cause.

Anyway, back to the topic, another fun fact about the image is that it was taken under the midnight sun. Here’s the original caption from NASA:
In September 2017, a new iceberg calved from Pine Island Glacier—one of the main outlets where the West Antarctic Ice Sheet flows into the ocean. Just weeks later, the berg named B-44 shattered into more than 20 fragments. On December 15, 2017, the Landsat 8 Earth-orbitng satellite took this image of the broken berg. An area of relatively warm water, known as a polyna, has kept the water ice free between the iceberg chunks and the glacier front. The polynya’s warm water could have caused the rapid breakup of B-44.

This image was acquired near midnight local time. Based on parameters including the azimuth of the Sun and its elevation above the horizon, as well as the length of the shadows, it is estimated that the iceberg rises about 49 meters above the water line. That would put the total thickness of the berg—above and below the water surface—at about 315 meters.

Image Credit: NASA

Larsen C

I’ve seen a few different views of Larsen C and this image from ESA’s Sentinel-1 spacecraft is one of the best and arguably the most interesting.

ESA — On 12 July 2017, Europe’s Copernicus Sentinel-1 mission returned radar images showing that a lump of ice more than twice the size of Luxembourg had broken off the Antarctic Peninsula. Since then, this large tabular iceberg – known as A68 – has drifted about 5 km from the ice shelf. Images from Sentinel-1 also show that a cluster of more than 11 smaller icebergs has also now formed, the largest of which is over 13 km long. These ‘bergy bits’ have broken off both the giant iceberg and the remaining ice shelf. The image has been compiled using Sentinel-1 acquisitions on 27 July (right) and 30 July (left).

Image contains modified Copernicus Sentinel data (2017), processed by BAS–A. Fleming.

New Zealand Quake of 2016

Our Earth observing satellites are constantly returning data of all types to us. The ARIA project, a wonderful collaboration shows us changes in surface displacements along two axis and it is quite amazing. Mother Earth is powerful!

The press release was timely because I was “told” just the other day the solar wind was causing the “increased” earthquake activity recently. I was helpless, all I could do is give the person a blank stare – lol. I don’t think I got to the drooling stage before the person explained they did hear it on the internet so it had to be true.

No it isn’t true about the solar wind and earthquake relationship – sorry. My blank stare was returned with the same when I explained I am open-minded about such things and please point me to the corroborating data and papers to support the conclusion. So take all those claims with a grain of salt.

Do check out the (really good) press release:
NASA and its partners are contributing important observations and expertise to the ongoing response to the Nov. 14, 2016, magnitude 7.8 Kaikoura earthquake in New Zealand. This shallow earthquake was so complex and unusual, it is likely to change how scientists think about earthquake hazards in plate boundary zones around the world.

Scientists with the Advanced Rapid Imaging and Analysis project (ARIA), a collaboration between NASA’s Jet Propulsion Laboratory, Pasadena, California, and Caltech in Pasadena, analyzed interferometric synthetic aperture radar images from the PALSAR-2 instrument on the ALOS-2 satellite operated by the Japan Aerospace Exploration Agency (JAXA) to calculate maps of the deformation of Earth’s surface caused by the quake. Two maps show motion of the surface in two different directions. Each false-color map shows the amount of permanent surface movement caused almost entirely by the earthquake, as viewed by the satellite, during a 28-day interval between two ALOS-2 wide-swath images acquired on Oct. 18 and Nov. 15, 2016.

In these two new maps made from the wide-swath images, the colors of the surface displacements are proportional to the surface motion. The wide-swath images cover the entire 106-mile (170-kilometer) length of the complex set of earthquake ruptures. The arrows show the direction of the radar motion measurement.

In the left image, the blue and purple tones show the areas where the land around the Kaikoura peninsula in the Marlborough region of New Zealand’s South Island has moved toward the satellite by up to 13.2 feet (4 meters), both eastward and upward. In the right image, the blue and purple tones show the areas that moved to the north by up to 30 feet (9 meters) and green tones show the area that moved to the south. The sharp line of color change is across the Kekerengu Fault, which had the largest amount of motion in the earthquake. Field studies found maximum rupture at the surface was measured at 39 feet (12 meters) of horizontal displacement. Several other faults have sharp color changes due to smaller amounts of motion, with a total of at least 12 faults rupturing in this single large earthquake. Areas without color have snow, heavy vegetation or open water that prevents the radar measurements from being coherent between satellite images – a required condition to measure ground displacement. Scientists use these maps to build detailed models of the fault slip at depth and associated land movements to better understand the impact on future earthquake activity. The PALSAR-2 data were provided by JAXA through the Committee on Earth Observation Satellites (CEOS) and through scientific research projects. The background image is from Google Earth.

Image Credit: NASA/JPL-Caltech/JAXA/Google Earth

GRACE is 15

15 years of looking back at us. One of the news stories I remember from back in 2014 was about the water shortage in the US State of California: “NASA Analysis: 11 Trillion Gallons to Replenish California Drought Losses” – 11 Trillion gallons!

That 11 trillion gallon deficient is abating thanks to a very wet and snowy winter. California Drought Status.

Have a look at the GRACE multimedia page.

Millennium Tower Sinking?


The sinking of the Millennium Tower has already sunk over 400 mm / 16 inches. As you would expect this is causing quite a lot of problems, summed up nicely by the NY Times.

The Sentinel data is rather amazing in showing how isolated the worst of the phenomenon seems to be.

From ESA:

Data from the Sentinel-1 satellites acquired between 22 February 2015 and 20 September 2016 show that Millennium Tower in San Francisco is sinking by about 40 mm a year in the ‘line of sight’ – the direction that the satellite is ‘looking’ at the building. This translates into a vertical subsidence of almost 50 mm (almost two inches) a year, assuming no tilting. The coloured dots represent targets observed by the radar. The colour scale ranges from 40 mm a year away from radar (red) to 40 mm a year towards radar (blue). Green represents stable targets.

Here’s the full article from ESA.

Copyright:   Contains modified Copernicus Sentinel data (2015–16) / ESA SEOM INSARAP study / PPO.labs / Norut / NGU