Upsala Glacier, Patagonia, Southern Argentina
Image ISS021-E-15242 (400 mm lens, acquired 25 Oct 2009, Figure above) shows the following:
Retreat of glacier tongues:
Icebergs preserving moraine lines:
- Probable continued retreat of the glacier snout. Although ISS021 imagery indicates a 2-km change of the snout of the glacier since an early 2002 image (ISS004; compare 2 panels below, left), long-term change is probably significantly less. Tongue position is complicated by seasonal surging (meltwater lubricates the ice-rock contact aiding downhill movement). Longer-term retreat of the tongue is nevertheless still probably occurring (published data show a 2–4 km retreat in a prior 27-yr period, 1968 - 1995). In a study of 63 glaciers in Patagonia, most were found to be retreating, with all but one of the large glaciers retreating.
- Probable retreat of an eastern arm of Upsala Glacier is also revealed in a small lake, where an island is now longer than it was in 2002 (compare 2 panels below, right). Again, the approximate 2.3 km change of tongue position may not reflect longer-term movement due to seasonal surging.
Detail of the surface of two of the largest calved icebergs shows the characteristic twinned lines of dark rocky moraine—reflecting the moraine pattern of Upsala glacier itself (arrows, upper panel below, left). It is unusual to see evidence of the parent glacier so clearly in icebergs. The fact that the moraines are so visible in the largest icebergs suggests that moraines make these icebergs more resistant to physical breakdown.
Critical Channel Open between Niger River and Lake Faguibine, Mali
Area of coverage: Lake Faguibine and supply channel, Mali, West Africa. Image center is 16.5N, 4W, as seen in the above figure.
Background: Niger River water is directed north from the great wetland known as the Inland Delta of the Niger, to a series of depressions for
recession agriculture, which is an unusual style of agriculture in which crops green up as the floodwaters slowly dry up. The end point of the system is the arrow-shaped Lake Faguibine. Sand dunes frequently cross narrow points preventing water from reaching the feeder zone, and the lake.
Removal of the dunes is a project being assisted with European funding. Images of the feeder zone, and crop health in lakes of the feeder zone and in Lake Faguibine itself are requested.
Significance: The crew's images show the channel that leads water 45 km from the Niger River to seasonally flooded Lake Faguibine, the arrow-shaped feature known to crews.
Water appears as very dark surfaces; these images show that water is flooding into Lake Faguibine (large dark area top right) on time (January and February each year). The crew's images show that the channel is cleared of sand.
Piece of a "super sandstorm"
Area of coverage: Arabian Sea, centered approximately 17N, 71E.
Significance: This ISS image records the second of two massive dust outblows from SW Asia that converged over the Arabian Sea. It was taken from a point half way between the tip of India and Somalia (nadir 7.45N 62.2E star, image below and left). The first event emanated from Afghanistan (MODIS image, image below and left).
This double dust event was reported on Earth Observatory website as follows:
According to Gulf News, several meteorologists characterized the dust activity as a
super sandstorm. The cause of the storms was likely the convergence of two different weather fronts. [One] carried dust from Iraq and Kuwait [21 March, Figure above], and the [other] front stirred dust in southeastern Iran [19 March, image below and right. This is a satellite image of the Arabian dust front.].
Dust storms have been raging across southwestern Asia and the Middle East in mid-March 2012. Intense dust events spanned thousands of kilometers from the Red Sea to Afgashistan, and from the Arabian Peninsula to India. Earlier in the month, dust was on the move in Iraq and Syria and along the African Atlantic and Mediterranean coasts.
On March 19, 2012, the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA Terra satellite captured this natural-color image [below] of a storm sweeping across Iran, Afghanistan, and Pakistan. Some source points are visible in southern Afghanistan, and the dust blew in southeast-northeast arcs. Most of the dust plumes in this storm were thick enough to completely obscure the land and water surfaces below.
A combination of sand seas and impermanent lakes occur along the borders between Iran, Pakistan, and Afghanistan, and the fine sediments there often provide material for dust storms. Read more