Tag: ice

Antarctic Meltwaters
Cerulean blue meltwater glints in this satellite image of the George VI Ice Shelf. Wedged between the Antarctic Peninsula on the right and Alexander Island on the left, the ice shelf itself floats on the ocean. When ice shelves collapse, they do not directly raise sea levels since their weight has already displaced water; but a collapsed ice shelf lets glaciers flow and break up faster, thereby raising water levels.
In past ice shelf collapses, scientists have noted major buildup and sudden drainage of surface lakes like the ones seen here. Meltwater penetrating through snow and ice can destabilize the shelf and hasten collapse, but the exact mechanisms are hard to track. This Physics Today article summarizes our understanding of the process and some of the methods scientists use to study it. (Image credit: L. Dauphin/NASA Earth Observatory; see also Physics Today)
February 1, 2022
The Return of the Ice Disk
Maine’s giant, spinning ice disk is taking shape again. In 2019, it reached about 91 meters across, rotating slowly in the Presumpscot River. How exactly these features form is still a matter of debate, but scientists have worked out a few relevant mechanisms. The spinning of the disk seems to depend on a vortex that forms beneath the ice as melting water sinks. (One of water’s peculiarities is that it’s densest around 4 degrees Celsius, so newly melted water is actually denser than ice. Otherwise ice wouldn’t float!) The plume of sinking water sets up a vortex that drags the ice disk with it as it spins in the river beneath. (Image credit: R. Bukaty/AP; via Gizmodo)
January 20, 2022
Filming a Calving Glacier
The San Rafael Glacier, one of the fastest calving glaciers in the world, sits above a fjord in Patagonia. About 10 – 25 meters of the glacier is lost to calving every day. Here, filmmakers take you behind-the-scenes to show what it takes to film in such a remote, unpredictable, and dangerous environment. (Image and video credit: BBC Earth)
November 2, 2021
Signs of Spring
Nothing says, “Goodbye, winter!” quite like watching the ice disappear after a deep freeze. This timelapse video shows ice on Lake Michigan breaking up after a deep freeze. The first chunk to go is a massive plate of ice that moves off in a single large chunk. After that, the break-up takes place on a smaller scale, with individual pieces of ice tracing the flow of local currents. (Video and image credit: WGN News; submitted by ajhir)
April 28, 2021
Albedo Effect
Temperature isn’t the only factor that determines how ice will melt. In this photo, a dark oak leaf absorbed more solar radiation than the reflective ice around it, causing the ice beneath it to melt. Scientifically, this effect is described by albedo; darker, more absorptive surfaces like the leaf have a lower albedo, whereas light, reflective ice and snow have a high albedo and can better resist melting on sunny days. (Image credit: K. James; submitted by Kam-Yung Soh)
April 5, 2021
The Best of FYFD 2020
2020 was certainly a strange year, and I confess that I mostly want to congratulate all of us for making it through and then look forward to a better, happier, healthier 2021. But for tradition and posterity’s sake, here were your top FYFD posts of 2020:
There’s a good mix of topics here! A little bit of biophysics, some research, some phenomena, and some good, old-fashioned fluid dynamics.
If you enjoy FYFD, please remember that it’s primarily reader-supported. You can help support the site by becoming a patron, making a one-time donation, buying some merch, or simply by sharing on social media. Happy New Year!
(Image credits: catfish – Abyss Dive Center, owl – J. Usherwood et al., masks – It’s Okay to Be Smart, droplet – C. Kalelkar and H. Sai, boundary layer – J. Lienhard, bubble – A. Patsyk et al., boiling – S. Mould, ice – D. Spitzer, defects – The Lutetium Project, tadpoles – K. Schwenk and J. Phillips)
January 1, 2021
A Colorful Portrait of Flow
This gorgeous, natural-color image shows Lake Balkhash in southeastern Kazakhstan. In early March, the ice on the lake was beginning to break up, revealing glimpses of swirling sediment below the water’s surface. In contrast, the smaller lakes and ponds of the surrounding area remained frozen amidst the wintery browns of the nearby desert and wetlands. (Image credit: J. Stevens/USGS; via NASA Earth Observatory)
October 15, 2020
Eroding Ice
When glaciers form, they do so in layers, with clear blue ice sandwiched between sediment and air-bubble-filled white ice. Because each of these layers absorbs sunlight differently, they don’t melt evenly. The spikes and ridges seen in this ice formed because of this differential melting between layers. The blue ice is particularly good at absorbing visible wavelengths of light, and so erodes more easily than the other layers.
Although the results look somewhat similar to the penitente ice seen at high altitudes, the formation mechanisms are a little different. Penitentes rely heavily on sublimation — where their ice and snow change directly into a gas — rather than the melting seen here. That said, both eroded forms depend strongly on how different layers within them absorb and scatter sunlight. (Image credit: J. Van Gundy; via EPOD; submitted by Kam-Yung Soh)
April 2, 2020
Ice Rings Caused By Underlying Eddies
Observations of strange ice rings on Lake Baikal, the world’s deepest lake, have puzzled scientists for decades. Surveys of satellite imagery have revealed rings on Baikal and two other lakes dating back to the 1960s and some of our earliest satellite images. The rings are roughly 5-7 km in diameter, with a dark layer of thin ice about 1 km wide around a brighter layer of thick ice.
A new study, buoyed in part by on-the-ground observations during Siberian winter, argues that the ice rings observed on the surface are related to eddies of warmer water circulating below. The researchers were able to capture several eddies in their measurements, including one migratory one. The size, shape, and location of these sub-surface eddies are consistent with ice ring appearance. The kilometers’ wide eddies are several degrees warmer at shallow depths and rotate approximately once every 3 days.
The researchers suspect the eddies form long before the ice does. Infrared observations in late autumn suggest the eddies form from a combination of wind and influx of river water into the lakes. Then, as ice does form, it’s affected by the underlying circulation. (Image credits: NASA, 1, 2; research credit: A. Kouraev et al.; via Gizmodo)
March 5, 2020
Ice Labyrinths
Pattern formation is extremely common in nature, from the dendritic growth of trees and snowflakes to the stripes of a tiger. A new paper describes how a thin layer of ice in a liquid can form labyrinthine patterns when illuminated with near-infrared light. Both the liquid and ice are maintained at a constant temperature below the melting point, but the ice absorbs the near-infrared light more effectively than the water. This means that parts of the ice that are far from the liquid warm and melt faster, creating holes that can then allow a pocket of liquid to seep in and reduce the absorption rate. The ice crystals themselves thin and expand across the surface at the expense of more holes, which eventually create larger channels that pock the ice. (Image and research credit: S. Preis et al.; via Nature; submitted by Kam-Yung Soh)
May 2, 2019