<p>Expanding on Friddy's third point, this could be the surface signature of what are called internal waves (<a href="https://en.wikipedia.org/wiki/Internal_wave" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Internal_wave</a>). The smooth regions indicate upward motion of internal waves and the rough regions indicate downward motion of internal waves. More information can be found here: <a href="http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves" rel="nofollow noreferrer">http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves</a></p>

CC BY-SA 3.0
2017-12-21T22:57:44.607Z
Internal waves often visible in the atmosphere. They can be frequent in mountainous areas. An example, as seen from an airplane: https://physics.fullerton.edu/gwpac/news/highlights/164-adrian-sacnas-2013
John
CC BY-SA 4.0
2021-03-11T04:28:53.473Z
Would I right in guessing that such waves would not be stationary?  Or is there some way they can be more perpetual, caused by like coastline\floor terrain and current?
JeopardyTempest
CC BY-SA 4.0
2021-03-11T19:40:03.923Z
@JeopardyTempest that is a good question. My knowledge on internal waves is focused on those caused by ocean tides over "rough" topography in the deep ocean. In that case, vertical motion will be sensitive to background stratification. Such waves have stationary and not stationary parts. As for what is shown in the photo, that could be caused by currents flowing over a bump. Depending on geometry/flow scales, they could be mostly stationary.
John
CC BY-SA 3.0
2017-12-21T16:45:57.130Z
2017-12-21T16:45:57.130Z
John
<p>I have gone over these in a fishing boat many times. I often use this as a fish locator with some shoaling fish around the Uk. One side to the other does show a difference in water temps on the temp sensors fitted to the hull.  It is my belief that these lanes are caused by differing temperature of water columns and an upwelling on the surface, between the 2 differing density of water. One being warmer than the other causes a density + temp fluctuation and the upwelling on collision. This upwelling caused the flat spots or lanes that can go for miles on times or maybe just a few hundred feet depending on the area at sea. Fish do tend to sit on one side or the other of these marks on the surface that appear dead flat and like river streams, flat on the sea surface apposed to the ripped water - They can be as wide as 20ft or more but often are no more than 10ft or less but are quite long and often going in one direction and then another.  So i would say this is more to do with Currents - tidal movements of water and differing water temp columns.
I would like to add - That salinity could also be part to play as many river pour into bay areas and i have overserved the flats spots during different stages of a tidal hight. Usually around top water when the water flows slow down some.</p>

CC BY-SA 4.0
2021-03-09T11:34:53.200Z
Yep +1, that's a nicely observed description of [Langmuir rolls](https://en.wikipedia.org/wiki/Langmuir_circulation).  They're generally driven by wind with temperature variations a consequence of the upwelling.  Things you mention like currents, salinity have a big effect on where these rolls can form.
Deditos
CC BY-SA 4.0
2022-09-20T15:13:05.463Z
This is great actual information compared to the guessing of many other answers. It would be *really* helpful to know if the water is colder in the upwelling or warmer compared to the surrounding water
leafmeal
CC BY-SA 4.0
2021-03-09T02:07:40.290Z
2021-03-09T02:15:17.340Z
2021-03-09T02:15:17.340Z
Luggy
<p>My guess is that it may be related to the currents, yes.
I suppose that the change in color, is due to a slightly different viscosity of the waters at the lanes, which may affect the reflecting light.
I think that if you could catch up swimming inside the lane, you would feel colder water.</p>

CC BY-SA 4.0
2020-06-20T17:46:19.427Z
You can improve your answer by adding some references and sources.
trond hansen
CC BY-SA 4.0
2020-06-20T15:35:25.250Z
2020-06-20T15:35:25.250Z
mixmix
<p>When the ocean is still, i.e. there aren't waves that disturb the surface, you often see "lanes" of water that seem flat as opposed to areas where the wind causes ripples. What causes this?</p>

<p><a href="https://i.sstatic.net/H8hAe.jpg" rel="noreferrer"><img src="https://i.sstatic.net/H8hAe.jpg" alt="enter image description here"></a></p>

CC BY-SA 4.0
2022-05-02T14:07:38.750Z
Has anyone considered that these flat streaks in the sea might be caused by some oily substance drifting along?
Jim  Hurford
<ocean><water>
Lanes of flat ocean surface in coastal waters
user8389
# Lanes of flat ocean surface in coastal waters

(Asked by: username_0 on 2017-06-19)

When the ocean is still, i.e. there aren't waves that disturb the surface, you often see "lanes" of water that seem flat as opposed to areas where the wind causes ripples. What causes this?

[![enter image description here](https://i.sstatic.net/H8hAe.jpg)](https://i.sstatic.net/H8hAe.jpg)

**Tags:** ocean, water

> **Comments:**
> **username_1**: Has anyone considered that these flat streaks in the sea might be caused by some oily substance drifting along?  

---

## 3 answers

### Answer by username_2 on 2017-12-21. Score: 3

Expanding on Friddy's third point, this could be the surface signature of what are called internal waves (<https://en.wikipedia.org/wiki/Internal_wave>). The smooth regions indicate upward motion of internal waves and the rough regions indicate downward motion of internal waves. More information can be found here: <http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves>

> **Comments:**
> **username_2**: Internal waves often visible in the atmosphere. They can be frequent in mountainous areas. An example, as seen from an airplane: https://physics.fullerton.edu/gwpac/news/highlights/164-adrian-sacnas-2013  
> **username_3**: Would I right in guessing that such waves would not be stationary?  Or is there some way they can be more perpetual, caused by like coastline\floor terrain and current?  
> **username_2**: @username_3 that is a good question. My knowledge on internal waves is focused on those caused by ocean tides over "rough" topography in the deep ocean. In that case, vertical motion will be sensitive to background stratification. Such waves have stationary and not stationary parts. As for what is shown in the photo, that could be caused by currents flowing over a bump. Depending on geometry/flow scales, they could be mostly stationary.  

---

### Answer by username_4 on 2021-03-09. Score: 3

I have gone over these in a fishing boat many times. I often use this as a fish locator with some shoaling fish around the Uk. One side to the other does show a difference in water temps on the temp sensors fitted to the hull. It is my belief that these lanes are caused by differing temperature of water columns and an upwelling on the surface, between the 2 differing density of water. One being warmer than the other causes a density + temp fluctuation and the upwelling on collision. This upwelling caused the flat spots or lanes that can go for miles on times or maybe just a few hundred feet depending on the area at sea. Fish do tend to sit on one side or the other of these marks on the surface that appear dead flat and like river streams, flat on the sea surface apposed to the ripped water - They can be as wide as 20ft or more but often are no more than 10ft or less but are quite long and often going in one direction and then another. So i would say this is more to do with Currents - tidal movements of water and differing water temp columns.
I would like to add - That salinity could also be part to play as many river pour into bay areas and i have overserved the flats spots during different stages of a tidal hight. Usually around top water when the water flows slow down some.

> **Comments:**
> **username_5**: Yep +1, that's a nicely observed description of [Langmuir rolls](https://en.wikipedia.org/wiki/Langmuir_circulation).  They're generally driven by wind with temperature variations a consequence of the upwelling.  Things you mention like currents, salinity have a big effect on where these rolls can form.  
> **username_6**: This is great actual information compared to the guessing of many other answers. It would be *really* helpful to know if the water is colder in the upwelling or warmer compared to the surrounding water  

---

### Answer by username_7 on 2020-06-20. Score: 1

My guess is that it may be related to the currents, yes.
I suppose that the change in color, is due to a slightly different viscosity of the waters at the lanes, which may affect the reflecting light.
I think that if you could catch up swimming inside the lane, you would feel colder water.

> **Comments:**
> **username_8**: You can improve your answer by adding some references and sources.  

---

