#landsat 5

[wigmund]

From NASA Earth Observatory Image of the Day; August 27, 2018:

Last Glacier Standing in Venezuela

In 1910, glaciers spanned an area of at least 10 square kilometers (4 square miles) in the mountainous region of northwestern Venezuela. Today less than one percent of that glaciated area remains, and all of it is locked up in one glacier. The ongoing retreat of Humboldt Glacier—Venezuela’s last patch of perennial ice—means that the country could soon be glacier-free.

The Operational Land Imager (OLI) on Landsat 8 acquired these natural-color images of the glacier on January 6, 2015. The top image is draped over topographic data from NASA’s Shuttle Radar Topography Mission (SRTM), and shows the glacier in context with the topography. The second image is a nadir view.

The glacier is within the Sierra Nevada de Mérida—the highest part of the Andes Mountains in Venezuela. It sits on a slope and saddle below the summit of the 4,942-meter-tall (16,214 feet) Pico Humboldt. For comparison, the nearby Pico Bolívar is the country’s highest peak at 4,978 meters (16,332 feet). The mountains here are remote and steep. In fact, the topography could be one reason why the glacier has not already disappeared.

Read More about Venezuela’s Humboldt Glacier at earthobservatory.nasa.gov

[wigmund]

From Earth Science Picture of the Day; January 29, 2017:

Archive - Snows of Kilimanjaro

Each Sunday we present a notable item from our archives. This EPOD was originally published January 7, 2003.

Provided By: Earth Observatory, NASA GSFC; Summary Authors & Editors: Earth Observatory, Jim Foster

If written today, Ernest Hemingway's short study about a writer contemplating his life as he's lying on the slopes of Africa's highest peak, would likely have a different title. Mt. Kilimanjaro's snow-capped crown (approximately 19,000 feet or 6,129 m) isn't as obvious now as it was earlier in the century. The above image pair of Mt. Kilimanjaro was taken 7-years apart. The upper image is from February 1993 (Landsat-5 satellite), while the bottom image was taken in February of 2000 (Landsat-7 satellite). What's alarming about these images is the rapidity of the disappearance of Kilimanjaro's ice cap. Some scientists think the mountain glaciers could be a thing of the past by the year 2015. The ice cap formed more than 11,000 years ago. Glaciologists believe the ice fields on Kilimanjaro shrank by 80 percent over the past century. In recent decades, about a foot and a half (46 cm) of the summit’s glacial ice has been lost each year as a result of increasing average annual temperatures. Most all tropical glaciers have experienced at least some shrinking during the last 30 years.

Related Links:

Kilimanjaro’s Shrinking Ice Fields

More about Mt. Kilimanjaro

Ernest Hemingway and "The Snows of Kilimanjaro"

[elvascoerrante]

Golfo de Fonseca (Honduras) Image taken from space , mangroves , wetlands, and shrimp farms in this image taken by landsat 5 in January 1999

[theatlantic]

What It Looks Like When One Satellite Sees Another

A rare snapshot of a satellite still in orbit.

Read more. [Image: NASA]

[maryhenrygeo]

Satellite image of... another satellite! Very cool.

[blech]

While the famous ‘Blue Marble’ photo illustrated that we all inhabit a single planet, it has been the Landsat missions, and none more than Landsat 5, that have informed us of the changing face of that planet over time.

Steven J. Covington, on the USGS Landsat 5 memorial page.

[blech]

From Wired's In Memoriam: The Space Robots We Lost This Year:

The longest lived Earth-observing satellite in history, Landsat 5 launched in 1984 and diligently watched the world change below it. During its life, it saw cities grow, forests shrink, glaciers retreat, and recorded the first images of key events such as the Chernobyl nuclear accident in 1986 and the devastating 2004 tsunami in southeast Asia. It helped establish a continuous record of our planet that allowed scientists to better understand weather, climate, and humanity’s effect on them.

[earth-as-art]

Iran’s Great Salt Desert

Roughly 300 kilometers (200 miles) east-southeast of Tehran lies Iran’s Dasht-e Kavir, or Great Salt Desert. To the untrained eye, Dasht-e Kavir looks like a place that has been bone-dry since the dawn of time. But to the well-trained eyes of a geologist, this desert tells a tale of wetter times. Tens of millions of years ago, a salt-rich ocean likely occupied this region, surrounding a microcontinent in what is now central Iran.

The Thematic Mapper on the Landsat 5 satellite captured this natural-color image of Dasht-e Kavir on October 15, 2011. The top image is a wide-area view, and the area outlined in white is then shown in the close-up view below.

Dasht-e Kavir is a complex landscape, but it can be mostly explained by the invasion and subsequent evaporation of an ancient ocean. As the ocean dried up, it left behind a layer of salt as much as 6 to 7 kilometers (4 miles) thick. Salt has a fairly low density, so if a layer of new rock buries the salt layer—and if that overlying rock is soft enough—the salt can slowly push up through it and form domes.

As its name implies, the Great Salt Desert is rich in salt domes, or diapirs. Geologists have identified about 50 large salt diapirs in this region. Like any other surface feature, a salt dome is subject to erosion. Wind and rain scrape away particles of rock, gradually wearing away the top of the dome and exposing it in cross-section.

But erosion is not the only force at work in this region. In the close-up view, we can see north-south-trending structures, some raised and some lowered. Callan Bentley, a geologist at Northern Virginia Community College, identifies them as folds or fault zones that run parallel to the trend of the region’s mountains. Bentley attributes the deformation of the salt domes to plate tectonic activity that has occurred since the salt domes formed. Bentley describes the landscape as a “a palimpsest tale that helps constrain the age of the diapirism to pre-folding.”