Friday, November 19, 2010

Rogue Waves

Rogue waves (also known as freak waves, monster waves, killer waves, extreme waves, and abnormal waves) are relatively large and spontaneous ocean surface waves that occur far out in sea, and are a threat even to large ships and ocean liners. In oceanography, they are more precisely defined as waves whose height is more than twice the significant wave height (SWH), which is itself defined as the mean of the largest third of waves in a wave record. Therefore rogue waves are not necessarily the biggest waves found at sea; they are, rather, surprisingly large waves for a given sea state. 


            
On March 3, a sudden wall of water hit a cruise ship sailing in the Mediterranean Sea off the northeastern coast of Spain, killing two people, injuring 14 and causing severe damage to the vessel. 
You can read more here: Cruise-Ship Disaster article


Below are some links to some amazing, yet terrifying rogue waves.
  1. A real rogue wave video
  2. Deadly Rogue Waves Rock Cruise Ship
  3. Spectators hurt by rogue wave

Wednesday, November 17, 2010

Clams

Quahogs, or hard-shell clams, are shellfish that inhabit the mud flats along the eastern seaboard from Canada to Florida. These big guys are also called chowder clams and weigh in at a mighty 2-3 clams per pound.
  

Cherry stone is a half-grown quahog. It can be eaten raw or cooked. You'd get 6-11 cherry stone clams per pound.

    


The geoduck clam ("gooey duck") is a giant clam found in salt water around the coasts of the Pacific Northwest, mainly Washington State and British Columbia. The average weight of an adult fresh geoduck clam is 2 pounds.

      

Sunday, November 7, 2010

Environmental Sensitivity Index (ESI) Maps

ESI maps provide a concise summary of coastal resources that are at risk if an oil spill occurs nearby. Examples of at-risk resources include biological resources (such as birds and shellfish beds), sensitive shorelines (such as marshes and tidal flats), and human-use resources (such as public beaches and parks).


When an oil spill occurs, ESI maps can help responders meet one of the main response objectives: reducing the environmental consequences of the spill and the cleanup efforts. Additionally, ESI maps can be used by planners--before a spill happens--to identify vulnerable locations, establish protection priorities, and identify cleanup strategies.


Here is an example of an ESI map of San Diego, California.



Wednesday, October 20, 2010

Glaciers and Icebergs

North and South Polar Ice Caps
Polar ice caps are huge sheets of ice that lie at a planet or moon's poles. Earth has ice caps at both the North and South Pole. The caps don't melt and re-freeze seasonally so they can be 10-13 feet (three to four meters) thick at the North Pole and even thicker at the South Pole (Antarctica). Polar ice caps get less exposure to the sun than the rest of the earth, which results in lower surface temperatures. Polar ice caps can grow and shrink due to climate variation.


Icebergs
Icebergs are pieces of ice that formed on land and float in an ocean or lake. Icebergs come in all shapes and sizes, from ice-cube-sized chunks to ice islands the size of a small country. Icebergs form when chunks of ice calve, or break off, from glaciers, ice shelves, or a larger iceberg. Icebergs travel with ocean currents, sometimes smashing up against the shore or getting caught in shallow waters. When an iceberg reaches warm waters, the new climate attacks it from all sides. On the iceberg surface, warm air melts snow and ice into pools called melt ponds that can trickle through the iceberg and widen cracks. At the same time, warm water laps at the iceberg edges, melting the ice and causing chunks of ice to break off. On the underside, warmer waters melt the iceberg from the bottom up.







Polar Ice Fluctuations
The poles go through cycles of ice advance and retreat every year depending on the season. However, it is the average diminishing ice concentrations that trouble scientists. Presented in the video (link below) are two years of ice concentration data from the NASA QuikSCAT satellite. NOAA uses this data to observe major trends in ice concentration.



Saturday, October 16, 2010

Light Attenuation

Light attenuation determines how fast the light intensity decreases with distance from objects. The light attenuation of various wavelengths of color in water was graphed for red (750nm), orange (700nm), orange (650nm), yellow (600nm), green (550nm), blue (500nm), and violet (450nm). By using the attenuation coefficient k (meters^-1), the depth Z (in meters) was determined based on the Iz/Io percentage as shown in the following equation:

 where,
     Z= depth (meters)
                                                  Iz= intensity of the light at a depth of Z meters
                                     Io= intensity of the light at the surface
                                     k= attenuation coefficient (meters^-1)

The results are graphed below using 1%-100% light attenuation and the specific k value for each color.



Tuesday, September 21, 2010

Journal Articles

The Oceanic Phosphorus Cycle
Phosphorus is an essential element to all life and this journal article describes how. This article illustrates phosphorus occurrence in the Earth's crust and its sources and sinks in the ocean. I learned that with the advent of new techniques, we have gained a greater understanding of the forms of phosphorus in the marine environment and how specific organism utilize each of these phosphorus pools. The phosphorus cycle is a very complex cycle and is not fully characterized yet.


The impacts of El Niño and La Niña on the U.S. climate during northern summer are analyzed separately in this journal article. Over most of North America during La Niña events a continental-scale peculiar high dominates, which leads to hot and dry summers over the central United States. The impacts of El Niño over North America, however, are weaker and more variable. In this article, there are many Figures that illustrate these impacts of El Niño and La Niña on the U.S. climate during northern summer.



Florida Red Tides are highly concentrated blooms of microscopic algae which occur annually along the coastlines of Florida and occasionally along other Gulf Coast states. This article describes the different species that pose health threats to humans and marine organisms. Many surveys and interviews were conducted for this article that help explore the various percepts of the risk surround red tides.

Wednesday, September 8, 2010

Bathymetric Map

During class, we learned about bathymetric maps. A bathymetric map is a map that shows water depth. We looked at a specific bathymetric map of a lake. We learned that when the lines are closer together, the slope is steeper. As a class, we divided each depth section among ourselves and cut out our specific section. I had sections 7, 8, 9, and 10 because they were the easiest to cut out. We also cut out a square for our scale. In class, we weighed both our square and cut out sections of the lake. The class average mass for the square scale was 0.103g. From the recorded masses of each section and the class average mass for the square, the area (meters squared) was calculated. The hypsographic curve (area vs depth curve) is shown below for our data.



Then we calculated the volume (meters cubed) for the data. The volume was determined by taking the average of two depth areas next to each other and multiplying it by the change in depth of the two areas. The Volume vs Depth curve is shown below. 


Sunday, August 29, 2010

Great Barrier Reef

One place that I would like to learn more about this semester in Oceanography is the Great Barrier Reef. The Great Barrier Reef is just off the coast of Australia and home to hundreds of different coral reefs and a variety of marine life.

The Great Barrier Reef is a UNESCO World Heritage Site, so it is a very significant place. One interesting fact I found about the Great Barrier Reef is that its structure can be seen from outer space! I really want to learn more about the Great Barrier Reef and why it is such a magnificent place.