17

Trench has a specific meaning in plate tectonics. It doesn't just refer to any valley; it specifically refers to the features formed at subduction zones by the flexure of the downgoing oceanic plate. A classic example is the Marianas Trench which is the location of the deepest point in the ocean Fast spreading ridges do indeed have valleys at their centre ...


12

It is an artifact of the processing software when it processes Multibeam Bathymetric Survey data. You can get the lines of the different surveys from NGBC at NOAA (https://maps.ngdc.noaa.gov/viewers/bathymetry/). As you can see in the image below both lines you see in your example correspond to multibeam data. In the area there is a fair amount of single-...


12

Meddies are anicyclonic (rotating clockwise) lenses of warm salty Mediterranean Water that travel through the North Atlantic between ∼500 and 1500 m depth. They are observed as large temperature, salinity and velocity anomalies (Richardson et al., 2000). Meddies are typically 40–100 km in diameter with their core being 500–1000 m thick. Meddies separate ...


8

Apart from the fact that only a few tropical cyclones follow a more southerly route (a list bellow) after going around the North Atlantic, I think the main problem is that tropical cyclones would weaken significantly after landfall in the Iberian Peninsula. An example of this is Hurricane Raphael in 2012. Source Weather.unisys.com. There is no "easy" path ...


7

Alex was an out of season freak event that bucked the trend and broke all the rules. As hurricanes go, it was somewhat weak, and could never have strengthened beyond category 1. Three conditions made it happen (i) there was an unusually strong vortex over Cuba which kick-started the rotation, (ii) the high level atmospheric shear, which usually kills off ...


7

Downwelling speeds in the deep water formation areas are likely not significant when compared with the settling speeds of most sediment particles. While deep waters have clearly defined oxygen and nutrient characteristics, it does not seem likely that they can have a particular sedimentary character. The deep water circulation associated with the meridional ...


6

The original question asked why there were no hurricanes in the southern hemisphere. The answer given: It really is just a naming convention based on location. You can see in the wikipedia article here: http://en.wikipedia.org/wiki/Tropical_cyclone#Classifications.2C_terminology.2C_and_naming , it says: Tropical cyclones are classified into three main ...


6

Alex was a weird development, being only the second ever recorded in any month to form north of 30°N and east of 30°W, the only other being Hurricane Vince in 2005. It developed over waters cooler than normally required for tropical development at 20-22°C, however upper level air was remarkably cold for the latitude above where Alex developed, giving a ...


5

Let's clear up the terminology first: trench A trench, as @bon has described in their answer, is formed where tectonic plates move towards each other and one of the plates is subducted under the other. @bon has also provided an illuminating illustration. The German term for an oceanic trench is Tiefseerinne (literally "deep sea groove"). rift-valley or ...


4

The shift appears to match up to a large change in the number of cyclones that peak as tropical storms in the early part of the TC season (here defined as March-July), shown by the blue (tropical storms) versus purple (hurricanes) in this graph (made using the HURDAT2 dataset from NHC): It appears that a large part of the increase in tropical storms lines ...


3

From Prandle 19791: The flow of water across the vertical component of the Earth's magnetic field induces a potential gradient in the water; measurements of the difference in voltage between the opposite sides of a tidal channel provide an indication of the magnitude of the tidal flow I imagine that having a cable across the channel enables an accurate ...


3

The most likely explanation is that a device similar to a hot wire anemometer has been used; but one that has been designed to be used in oceans. A hot wire anemometer is basically an electric heater that has been calibrated. The heating element radiates heat into a surrounding medium, depending on the design and construction of the anemometer, either air ...


3

The Guinea Current is in geostrophic balance with isopycnals sloping upwards towards the north. The current is not directly related to wind direction and magnitude and that makes rather especial. As many other eastern boundary currents, it is characterized by the presence of coastal upwelling (Bakun, 1978), which delivers nutrients to the surface waters and ...


2

Mediterranean tropical cyclones are extremely rare but do occur. These are not Atlantic type hurricanes, they are typically not the product of a hot African tropical depression. The most recent event was in November 7, 2014 3. As for Atlantic basic hurricanes, it would seem nearly impossible. The normal path of the storm leading it eastwards would be ...


2

Tropopause temperatures were unusually cold. This allowed a steep enough lapse rate despite cool sea surface temperatures of 68 degrees F, and was one of the factors that helped Alex to form despite such cool sea surface temperatures. Hurricanes are heat engines with the hot source at the ocean surface and the cold sink at the tropopause. Thus an unusually ...


2

I can't see there being any physical cause - the water depths are too great for an ice mountain and the feature cross-cuts other geological features. Plus, it's not aligned with either the spreading axis of the mid Atlantic ridge or normal to it. That means that it is highly unlikely to be a fault or a hotspot track. Given that, some sort of processing ...


1

The Bermuda high is centered near the horse latitudes, where air from the tropical Hadley trade wind cell is sinking. This forced sinking of air can dynamically contribute to high pressure even if the air is warm --- warm air can be forced to sink against its own buoyancy in a Ferrel-type circulation. But the Bermuda high is helped thermally too, at least in ...


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