Monday, July 30, 2018

The Twin Eau Claire Craters of Northwestern Quebec


Description:
This NASA Earth Observatory image titled “A One-Two Punch” exhibits a double crater landscape in northwestern Quebec. This event was originally believed to have been the result of a binary asteroid in the Carboniferous Period. The Eau Claire lakes have the unique round shape of complex craters including peak rings caused by the impact, forming a small, rounded chain of islands. The limited topsoil of the area leads to the grey-tan shade of the landscape and limited vegetation cover. This unique, tundra like landscape is the result of glacial scraping that formed elongated lake shapes but left the craters in the bedrock. They removed the lighter debris and impact mounds of the older-than-glacial craters, revealing their extent and shape. The larger lake, Eau Claire West, is 36 km (22mi) in diameter with the smaller eastern lake being 26 km (16 mi) in diameter.

It has recently (2014) come to light that the craters were likely formed about 200 million years apart from each other.
They say lightning doesn't strike the same place twice, but I guess asteroids might? 

Coordinates: 56°08′N 74°18′W 

Thursday, July 26, 2018

Avalanche Caught in the Act



This false-color image captured by the Thematic Mapper sensor on Landsat 5 on April 17 of 1996. I was drawn to this image not only from the striking color composite and aesthetic appeal, but also the curious event captured within it. Can you spot the billowing plume of an avalanche? 

The area captured in the image is the Karakoram range in Northern Pakistan. The image combines infrared, red and green wavelengths. I'm interested to know which band on Landsat 5 TM was used for infrared. The post does not specify, and it is certainly a unique combination of colors and bands to produce this imagery. In this image snow appears red, exposed moraine and soil is cyan, and shadows appear black. 
In the central region of the image there is a unique, billowy feature that is an avalanche that was captured by the Landsat 5 TM. The avalanche occurred on a SE flank of Kanjut Sar, the 26th highest mountain on earth at 7760meters.

Satellite imagery of an avalanche as it's occurring seems to be a fairly rare occurrence -- especially historically as temporal resolution was lower. Getting a synoptic view of large-scale avalanches as they're occurring sounds like it may pretty interesting to scientists hoping to understand avalanche behavior, or where they're likely to occur. 

This image was happened upon by a research team investigating surging glaciers -- glaciers which do not have a constant or predictable flow, and are subjected to cyclical flow instabilities. In going down that rabbit-hole, I came across this gif the research team composed of the karakoram range's surging glaciers during a period of high advancement.

I also enjoyed reading about the 'medial moraine' bands that are produced from surging glaciers. These strips of rock and debris can be seen as the blue stripes down the center of the red glaciers, creating a beautiful pattern. 

Link:

Tuesday, July 24, 2018

The Art and Beauty of Nature - Malaspina Glacier, Mt. Saint Elias, Yakutat Bay, Alaska





     This image is of the Malaspina Glacier in southeast Alaska. I have included a false color image and a "true color" image for comparison.  The Malaspina Glacier is the largest piedmont (located at the foot of a mountainous region) glacier in North America, and according to Wikipedia "it is the largest piedmont glacier in the world." This image was taken through use of the OLI sensor onboard Landsat 8 on Sept. 24, 2014.
     Of all the 100,000+ glaciers in Alaska, the Malaspina Glacier is unique because it is a compound glacier formed by the merging of the Agassiz Glacier to the left and the better known Seward Glacier (alpine or valley glacier) from above. Resembling an alluvial fan, the Malaspina Glacier is approximately 40 miles "wide" x 30 miles "long."  Also pictured are the Agassiz Glacier to the left and Hayden Glacier to the right. 







https://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86767/malaspina_oli_2014267_lrg.jpg



References:
www.caltech.edu
https://earthobservatory.nasa.gov


Sunday, July 8, 2018

Imagery of the Day, July 2nd




Description: 
From left to right, the date is 10/29/2017, 11/30/2017, 12/16/2017.
The location I focus on is Bali, Indonesia. Which is in the left part of each imagery. If we zoom in, we can see Mountain Agung, an active volcano. In the first imagery, we can clearly see the red, bright magma. And there are lots of ash in the second imagery. The ash went off in the third, but the magma still exists, meaning an unfinished eruption. 
Links to relevant website(s): 

Image of the day, July 9, 2018


















Description: 

This image displays the before and after satellite images of an area in Tambopata National Reserve, a protected area in Peru. The one on the left is the before image (September 2015) of when the area was in its more or less natural state. The one on the right is the after image (November 2015) taken after the area was invaded by an illegal gold mining operation. You can see that some of the forests have been cut and parts of the river have been invaded with mining equipment. Deforestation as a result of illegal mining is apparently a big problem in the area.  Gold mining not only causes habitat loss and endangers different species because of that, it also causes mercury pollution, as well as violence to the local communities. 

This image is important because it shows how we can use satellite images to detect illegal activities that have negative impacts on our forests, the environment, and the communities. 

Links to relevant website(s):

Monday, July 2, 2018

The dramatic change of Jiuzhai Valley after an earthquake


Description: 
This is a image that shows the views in Jiuzhai Valley before and after an earthquake which happened in August 8th,2017.  Jiuzhai Valley is a beautiful attraction of Sichuang Province in China, but the earthquake destroyed the scenery. From the image, we can see that where used to be a beautiful lake is buried with soil and trees. The image can give us a clear look of the disaster situation. Additionally, the road laid beside the lake has been destroyed, so aerial photos can make us accessible to the inside conditions which may not be able to see in person and help us to make preparations for repair works. And it is said that the landscape restoration in Jiuzhai Valley may be a long process.

Source:

Lake Erie Blue-Green Algae Bloom, July 2, 2018



This image shows an aerial view of Lake Erie taken in 2011 of a toxic blue-green algae bloom. The neon green of the algal bloom can be seen coating the surface of the dark blue water of the lake. The bright neon green swirly algae has tendrils that stretch a great distance of the lake in this image. Some almost stretching across the entire width in some places. Most of the algae is concentrated around the coast between the blue lake and the brown/green land.
This image is important because these algal blooms can cause harm and even death in humans or animals that swim in these areas. Algal blooms also impact the water quality and the organisms that live in the water. Phosphorus is the main factor that contributes to algal blooms. When the algae feed they take many essential nutrients out of the water. Most important of all is the large quantity of oxygen taken from the lake. This high decrease in oxygen kills other plants and aquatic organisms. The algal blooms are indicators of runoff from agriculture (fertilizers, animal waste), wastewater treatments plants, and industry. This image could be used in researching methods to decrease these blooms. Such as, if implementing new policy on fertilizer runoff  impacts the size/amount of algal blooms.

Links to relevant website(s):


Images of Mendota/Monona algal bloom: http://blooms.uwcfl.org/mendota/