Does the range of tide increase with increasing latitude?


#1

No.

Where is the highest tide?

The highest tides in the world can be found in Canada at the Bay of Fundy, which separates New Brunswick from Nova Scotia.

The highest tides in the United States can be found near Anchorage, Alaska, with tidal ranges up to 40 feet.

Tidal highs and lows depend on a lot of different factors. The shape and geometry of a coastline play a major role, as do the locations of the Sun and Moon. Storm systems at sea and on land also shift large quantities of water around and affect the tides. Detailed forecasts are available for high and low tides in all sea ports, but are specific to local conditions.

That many of the areas of the world with high ranges of tides are in the areas of Alaska, Canada, and northern Europe has created a misconception that the range of tide increases with increasing latitude (as one moves farther from the equator and closer to the poles). This is incorrect.

Increased tidal ranges in these areas are created by the positions and configurations of the continents in the northern hemisphere. In the higher latitudes of the northern hemisphere, the continents of North America, Europe, and Asia are pressed closer together. This “constriction” of the oceans creates the effect of a higher range of tides.

In the higher latitudes of the southern hemisphere, in the southern tips of South America, southern Africa, Australia, and Antarctica, tidal ranges are not increased. In these areas the continents are not pressed closely together, there is not a “constriction” of the oceans, and the tidal ranges are not increased.


#2

Narragansett Bay, in Rhode Island where I live, has its own tidal system that’s smaller range and about three hours offset from the rest of the coast.


#3

And in a large shallow area like the Chesapeake, prolonged winds can totally overwhelm the tide.


#4

An onshore or offshore breeze will often produce more rise and fall of sea level a long the coast than the change in tide level in most of the Alaskan Arctic and in the Bering Sea. However, some of the rivers have significant changes in tidal levels.


#5

On the southern tip of South America there is a large tidal range.(>11 m. ) I used to move a jackup rig there back in 1982-83 and it was a big problem for pre-loading, which could only be done close to HW or LW to avoid either getting a very large airgap as the tide fell, or getting caught with the hull in the water on a rising tide. (We figured out a way to do it leg by leg on both HW and LW slack)
Baia San Sebastian tide table:https://tides4fishing.com/ar/tierra-del-fuego/bahia-san-sebastian#_tide_table

That it is not only latitude that affect tides are obvious, just have a look at the difference in tides between southern coast of Norway and northern part of Scotland. Only a few hundred n,miles apart and close in latitude, but a very big difference in tidal range .


#6

Yes, there are some big tides in the southern end of S. America. Perhaps the article should have differentiated between local vs larger areas.

I have heard the view that tides range is related to latitude a few times. For someone living on the U.S. West Coast it easy to see why this view is common.

Here is a graphic from NASA:

The same is true to a lesser degree on the U.S. East Coast, howver the big tides at Fundy are barely visible here, the big tides there are also due to local conditions, the Bay is resonant to the Atlantic tides.


#7

Thanks for the thread. I admit to once thinking that tidal ranges increased with latitude, based mainly off the tide range in the Gulf of Mexico vs the tidal range in Bay of Fundy. This post got me to thinking so I have a question….
Are faster currents associated with larger tide changes? I would say a lot depends upon the slope or terrain of the area. The elevation drop, or better stated depth change, plays a role in this. I was reading about the very fast current in Normandy France (45 foot tide range). Here the coastal area is very flat, with very little elevation change. If the area was like say the tip of Baja California where you can leave shore and be in 9,000-10,000 ft in 45 mins, the current would act much differently right? The rise over run or dropoff is much more drastic. This plays an important role I imagine. Am I wrong in thinking this for coastal areas that have a flood and ebb tidal current? And also, would faster currents be more common with larger tide changes or is there no association? Are there areas that have a very drastic tide range but very slow current?


#8

image
I’ve experienced the tides in Alaska and the Canadian east coast but in retirement, I deal with tide in the shallow estuaries in Texas. With the semidiurnal tides of generally 1 ft at the most, one has to be aware of all influences. The biggest variations from the projected tides are from the wind driven currents along the coast and barometric pressure.
I’ve seen several fishermen over the years left stuck overnight in a muddy slough surrounded by man-eating oysters.


#9

There are some very big tides in the Channel Islands off NW France. They are caused by the way the Cherbourg peninsular squeezes the Atlantic ocean into a narrow gap between the UK and France as it becomes the English Channel.

PS the French call it La Manche. But they lost the Battle of Waterloo so it is the English Channel.


#10

There is for sure a relationship between tidal height and current strength. For example Cook Inlet in Alaska. Also in restrictions in channels in BC and SE Alaska give rise to hydraulic currents, for example Seymour Narrows sometimes has 15 or 16 kts of current.

Some coastal areas have simple reversing currents but some have rotary currents. Swiftsure Bank in the Straits of Juan de Fuca for example.

Here is a diagram for the rotary current at Nantucket Shoals Lightship.

image

I don’t recall where these diagrams are found, I think I’ve seen them printed on the charts but I’ve not seen one in a while.

Here’s a good explanation of rotary currents from David Burch Understanding Rotary Currents