pacific central

How Do Hurricanes Form?

Hurricanes are the most violent storms on Earth. People call these storms by other names, such as typhoons or cyclones, depending on where they occur.

The scientific term for ALL of these storms is tropical cyclone. Only tropical cyclones that form over the Atlantic Ocean or eastern and central Pacific Ocean are called “hurricanes.”

Whatever they are called, tropical cyclones all form the same way.

Tropical cyclones are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. This warm, moist air rises and condenses to form clouds and storms.

As this warmer, moister air rises, there’s less air left near the Earth’s surface. Essentially, as this warm air rises, this causes an area of lower air pressure below.

This starts the ‘engine’ of the storm. To fill in the low pressure area, air from surrounding areas with higher air pressure pushes in. That “new” air near the Earth’s surface also gets heated by the warm ocean water so it also gets warmer and moister and then it rises.

As the warm air continues to rise, the surrounding air swirls in to take its place. The whole system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface.

As the storm system rotates faster and faster, an eye forms in the center. It is vey calm and clear in the eye, with very low air pressure.

Tropical cyclones usually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. However, when they move inland, they can drop many inches of rain causing flooding as well as wind damage before they die out completely. 

There are five types, or categories, of hurricanes. The scale of categories is called the Saffir-Simpson Hurricane Scale and they are based on wind speed.

How Does NASA Study Hurricanes?

Our satellites gather information from space that are made into pictures. Some satellite instruments measure cloud and ocean temperatures. Others measure the height of clouds and how fast rain is falling. Still others measure the speed and direction of winds.

We also fly airplanes into and above hurricanes. The instruments aboard planes gather details about the storm. Some parts are too dangerous for people to fly into. To study these parts, we use airplanes that operate without people. 

Learn more about this and other questions by exploring NASA Space Place and the NASA/NOAA SciJinks that offer explanations of science topics for school kids.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Credits: NASA Space Place & NASA/NOAA SciJinks

3

The 2011 Japanese tsunami washed away an entire forest on the country’s central Pacific coast, except for a lone pine tree. Out of 70,000 trees, the 250-year-old pine tree in Rikuzentakata was the only survivor. It was quickly named the Miracle Pine.

Unfortunately the high salinity of the ground, caused by the tsunami, slowly weakened the tree. When it died 18 months after the tsunami, a metal skeleton was inserted into its trunk, replica branches and leaves were added, and scaffolding was erected so the tree would stand as it did after the tsunami, a tall testament to the tragedy that happened there.

A powerful earthquake hit off Mexico’s southern coast late Thursday night, toppling houses in Chiapas state. Dozens of aftershocks have also been felt. At least five people were reported killed.

The U.S. Geological Survey said the 8.1-magnitute quake struck at 11:49 p.m. local time and its epicenter was 102 miles west of Tapachula in Chiapas — not far from Guatemala.

Mexican President Enrique Pena Nieto says it was an 8.2 quake — making it the largest in Mexico in 100 years. He also said it was bigger than the one in 1985, when thousands were killed in four Mexican states.

The U.S. Tsunami Warning System said hazardous tsunami waves were possible on the Pacific coasts of several Central American countries, including Guatemala, El Salvador, Costa Rica, Nicaragua, Panama and Honduras, within three hours.

Deadly Earthquake Off Southern Mexico Triggers Tsunami Warning

Photo: Pedro Pardo/AFP/Getty Images

2

TESTUDINE TUESDAY

-Classification-

Common Name: Green Sea Turtle

Aliases: Green Turtle, Black Sea Turtle, Pacific Green Turtle

Scientific Name: Chelonia mydas


                                                   Kingdom: Animalia

                                                    Phylum: Chordata

                                                       Class: Reptilia

                                                     Order: Testudines

                                                  Suborder: Cryptodira

                                                  Clade: Americhelydia

                                                   Family: Cheloniidae

                                                      Genus: Chelonia

                                                     Species: C.mydas


-General Info-

Size: Adults can reach up to 5 feet long (1.5 meters).

Weight: Adults can weigh up to 150 - 419 pounds (68 - 190 kilograms).

Carapace Length (Shell): Adults on average have a shell length between 31 - 44 inches (78 - 112 centimeters).

Gender Differences: Males have a slightly longer tail and are overall larger than females in size. Males also have longer claws on their front flippers. However, both do have paddle-like flippers which aid in their swimming. 

Lifespan (Wild): Green Sea Turtles that reach maturity can live for roughly 80 years.

Diet: Juvenile Green Sea Turtles are initially carnivorous (diet consists mainly or exclusively of meat) eating things like mollusks (snails and clams), sponges, algae, and even fish eggs. As they’re maturing, they’ll incorporate plants into their diet and are considered omnivorous (diet consists of both meats and plants). Once they’re fully-grown adults, most of them are herbivores and have cut out meat in their diets due to their serrated jaw (saw-like) which helps them chew plant life like various sea grasses and algae.

Group: A group of Sea Turtles is called a bale.

                                          

-Habitat and Lifestyle-

Life Cycle: Almost everyone knows that Sea Turtles hatch from eggs that are laid on beaches in Southeast Asia, India, western Pacific islands, and Central America. One of the most dangerous events in a Sea Turtle’s life happens as soon as they hatch. As they attempt to flee into the ocean they may be attacked by predators like birds and crabs; a big percentage of hatchlings won’t make it to the water. Juveniles who did make it to the water spend anywhere from 3 - 5 years in the deep ocean. After their years of exploration, the juveniles will find shallow watered areas to call home for the rest of their days. Sadly, estimations say that only about 1% of Sea turtle hatchlings will make it to sexual maturity which occurs after about 20 - 50 years. Finally, once mating occurs the female will breach the ocean’s surface past the high tide line of the beach to lay her eggs. She then returns back to the sea. 

Breeding: Mating occurs every 2 - 4 years.

Gender Deciding Factors: Nests in areas above 30 degrees Celsius tend to favor female hatchlings whereas areas below 30 degrees Celsius tend to favor male hatchlings. Egg positioning also plays a role in whether a hatchling may be male or female. If the egg is more towards the center of the nest then it has a higher chance of resulting in a female hatchling due to the center being warmer.

Number of Eggs per Nest: Each nest will contain about 110 eggs.

Number of Nests per Season: On average, a female Sea Turtle can create 2 - 8 nests in a single season.

Habitats: Generally, Green Sea Turtles stay near island and continental coastlines. Depending on their stage in life, Green Sea Turtles can be found in many different types of environments. Younger juveniles can be found in the open ocean as they spend years swimming around before they settle down. Older juveniles and mature adults will find permanent residence in areas that are more shallow like coral reefs, seagrass beds near shore, and salt marshes. These areas are generally good spots for protecting the turtles. Globally, you can find Sea Turtles in warm tropical waters to subtropical waters. 

                  

-Role in the Ecosystem and Endangerment-

Ecosystem Roles: In the varying areas Sea Turtles can be found, they have a strikingly powerful role to play in each. For instance, on the beaches where their eggs lay cracked and empty, key nutrients are given to the ecosystem through the eggshells. For the turtles located in the seagrass beds, they feed on the seagrass and in doing so they improve the health and development of the seagrass; this in turn results in a suitable habitat and place for feeding for various species of fish and crustaceans (crabs, shrimp, barnacles, crayfish, etc). 

Conservation Status: Green Sea Turtles are listed as Endangered whereas some subpopulations in the Mediterranean are listed as Critically Endangered. Some human-caused threats include being hunted, poached, and having their eggs collected. Whereas accidental threats like boats, pollution, habitat destruction, and fishing nets are reducing the population as well.