Hurricanes

So you think they are caused by heat?

Well here's some hot water for you! …

Originally posted by Wikipedia:

A tropical cyclone is a storm system characterized by a low-pressure center and numerous thunderstorms that produce strong winds and heavy rain.

Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor contained in the moist air.

They are fueled by a different heat mechanism than other cyclonic windstorms such as nor'easters, European windstorms, and polar lows. The characteristic that separates tropical cyclones from other cyclonic systems is that at any height in the atmosphere, the center of a tropical cyclone will be warmer than its surroundings; a phenomenon called "warm core" storm systems.

So they get warm and stay warm all the while acting as the most potent refrigerants imaginable:
"water, evaporated from the ocean is released as the air rises"

Originally posted by Wikipedia:

Water. Water has the highest volumetric heat capacity of all commonly used material. Typically, it is placed in large container(s), acrylic tubes for example, in an area with direct sunlight. It may also be used to saturate other types material such as soil to increase heat capacity.

Analyse this:

Originally posted by Wikipedia:

Tropical cyclones can produce extremely powerful winds and torrential rain, they are also able to produce high waves and damaging storm surge as well as spawning tornadoes.

They develop over large bodies of warm water and lose their strength if they move over land due to increased surface friction and loss of the warm ocean as an energy source.

How are we doing so far?
1. It takes a lot to heat water.
2. Hurricanes do an amazing amount of work.
3. They require warm water. LOTS of it.

Now let's look at a couple of hurricanes:
Daniel:

Originally posted by Wikipedia:

Early on July 2, the National Hurricane Center began monitoring an area of disturbed weather about 475 mi south-south-east of Acapulco.

Over the next 24 hours, the disturbance continued to become increasingly better organized, and a Tropical Cyclone Formation Alert was issued on the system early on July 3.

By early on July 4, the system had gained enough organization to be declared as Tropical Depression Four-E.
On July 5, Four-E became Tropical Storm Daniel.

The cyclone then slowly intensified, and after having been situated over a favourable environment for two days, it intensified into a hurricane.
Overnight July 7 to July 8, Daniel rapidly intensified further into a Category 2 hurricane with sustained winds of 105 mph (165 km/h).
Later that day, Daniel reached a peak intensity of 115 mph and a central pressure of 961 millibars, a Category 3 hurricane, although the eye was already over cooler waters.

Daniel maintained Category 3 status briefly, and six hours later, the eye became less well-defined and the storm weakened back to a Category 2 hurricane. By July 9, Daniel had weakened further to a Category 1.

Early on July 10, Daniel continued to weakened into a tropical storm, as the system became smaller in size, over cooler waters.
On July 11, Daniel's low level circulation centre started to become exposed under moderate vertical wind shear. It further weakened into a tropical depression later that day and then degenerated into a remnant low east-south-east of Hawaii.

Did you notice that it required warm water and found it after "being cloudy weather" for some time?
Of course a lot depends on what you call "disturbed weather".

The picture above was from 7 July but the area covered by the disturbed air was nearly as large, I'll bet.
I think the area is something like a square degree or two. And hundred miles or more in diameter. Pi x r x r = 3 x 50 x 50 or so.
3 x 50 x 50 = 7500 square miles.

Originally posted by Wikipedia:

One measure of the size of a tropical cyclone is determined by measuring the distance from its centre of circulation to its outermost closed isobar.

If the radius is less than two degrees of latitude or 222 kilometres (138 mi), then the cyclone is "very small" or a "midget".

A radius between 3 and 6 latitude degrees or 333 to 670 kilometres (207 to 420 mi) are considered "average-sized".

"Very large" tropical cyclones have a radius of greater than 8 degrees or 888 kilometres (552 mi).

Use of this measure has objectively determined that tropical cyclones in the north-west Pacific Ocean are the largest on earth, with North Atlantic tropical cyclones roughly half their size.

So now we have:
Very large surface areas blocking the sun for quite long periods.
Doing an hell of a lot of work.

Where is it getting the energy from?

Originally posted by Wikipedia edited:

Albedo is the diffuse reflectivity or reflecting power of a surface. (Reflection coefficient.)

From Latin albedo "whiteness" (or reflected sunlight) it is defined as the ratio of reflected radiation from the surface to incident radiation upon it.

It may be expressed as a percentage, from zero (a perfectly black surface) to unity (1) for perfect reflection of a white surface.

Albedo depends on the frequency of the radiation.
When quoted unqualified, it usually refers to some appropriate average across the spectrum of visible light.

In general, the albedo depends on the directional distribution of incoming radiation.

Originally posted by Wikipedia:

Cloud albedo is a measure of the albedo of a cloud – higher values mean that the cloud reflects more solar radiation, or less radiation is transmitted.

Cloud albedo varies from less than 10% to more than 90% and depends on drop sizes, liquid water or ice content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the greater the liquid water content, the greater the cloud albedo, if all other factors are the same.

Low, thick clouds (such as strato-cumulus) primarily reflect incoming solar radiation, causing it to have a high albedo, whereas high, thin clouds (such as Cirrus) tend to transmit it to the surface but then trap outgoing infrared radiation, causing it to have low albedo. It contributes to the greenhouse effect.

Trust me, storm clouds are dark from underneath them.
That latter version in the quote might be referring to the angle that the sunlight hits them at.

After a storm it is bright because the higher cloud resulting from the storm is broken and at higher altitude. Thus it reflects and refracts more sunlight into a region that would otherwise fall on that region with clear skies.

So somewhere else is being robbed, right?

So tell me; have you learned anything?
K?

Where did this come from:
Emilia

Advertisements

One thought on “Hurricanes

  1. Since I started writing this blog, about 3 or 4 hours ago, another tropical storm has spun into life:Originally posted by Tropical Storm Risk:

    DANIEL NE Pacific 15.5 N 143.7 W 30 kts TD EMILIA NE Pacific 15.2 N 120.2 W 95 kts Cat 206E NE Pacific 13.6 N 106.4 W 30 kts TD

    They are all, more or less, on the same path:15.5 N, 15.2 N and 13.6 N.And they are all about 20 degrees apart.143.7 W, 120.2 W, and 106.4 W.Where on earth is that warm water coming from?Heaven?Or was it an accident?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s