Google Play icon

Gravity waves and sunglint, lake superior

Share
Posted July 23, 2013
Image credit: NASA

Image Credit: NASA

From the vantage point of the International Space Station, astronauts frequently observe atmospheric and surface phenomena in ways that are impossible to view from the ground. Two such phenomena—gravity waves and sunglint—are illustrated in this photograph of northeastern Lake Superior.

At the top of the image, the Canadian Shield of southern Ontario is covered by an extensive forest canopy typical of early summer. Offshore and to the west and southwest of Pukaskwa National Park, several distinct sets of parallel cloud bands are visible. Gravity waves are produced when moisture-laden air encounters imbalances in air density, such as might be expected when cool air flows over warmer air. This can cause the flowing air to oscillate up and down as it moves, causing clouds to condense as the air rises and cools and to evaporate away as the air sinks and warms. This produces parallel bands of clouds oriented perpendicular to the wind direction. The orientation of the cloud bands in this image, parallel to the coastlines, suggests that air flowing off of the land surfaces to the north is interacting with moist, stable air over the lake surface, creating gravity waves.

The second phenomenon—sunglint—affects the water surface around and to the northeast of Isle Royale. Sunglint is caused by light reflection off a water surface; some of the reflected light travels directly back towards the observer, resulting in a bright mirror-like appearance over large expanses of water. Water currents and changes in surface tension—typically caused by presence of oils or surfactants—alter the reflective properties of the water and can be highlighted by sunglint. For example, surface water currents are visible to the east of Isle Royale that are oriented similarly to the gravity waves, suggesting that they too are the product of winds moving off of the land surface.

Read more at: Phys.org

Featured news from related categories:

Technology Org App
Google Play icon
84,754 science & technology articles

Most Popular Articles

  1. Real Artificial Gravity for SpaceX Starship (September 17, 2019)
  2. Top NASA Manager Says the 2024 Moon Landing by Astronauts might not Happen (September 19, 2019)
  3. How social media altered the good parenting ideal (September 4, 2019)
  4. What's the difference between offensive and defensive hand grenades? (September 26, 2019)
  5. Just How Feasible is a Warp Drive? (September 25, 2019)

Follow us

Facebook   Twitter   Pinterest   Tumblr   RSS   Newsletter via Email