DATASTREME OCEAN WEEK EIGHT: 18-22 March 2013

Items of Interest:

• Notice the Equinox -- The vernal equinox, which marks the commencement of astronomical spring, will occur this Wednesday (20 March 2013 at 1102 UTC or 7:02 AM EDT, 6:07 AM CDT, etc.), If you checked the sunrise and sunset times in your local newspaper or from the climate page at your local National Weather Service Office, you would probably find that by midweek, the sun should have been above the horizon for at least 12 hours at most locations. As discussed previously, the effects of atmospheric refraction (bending of light rays by the varying density of the atmosphere) along with a relatively large diameter of the sun contribute to several additional minutes that the sun appears above the horizon at sunrise and sunset.
• International observances -- Several days during this upcoming week have been designated as special days that are intended to focus public attention on the environment and earth science:
• "Earth-Sun Day"-- Since this coming Wednesday (20 March 2013) is the vernal equinox, this day has been declared Earth-Sun Day, which includes a series of programs and events that occur throughout the year culminating with a celebration on the Spring Equinox. This year's theme is "Solar Max – Storm Warning!" that is designed to explore the violent nature of the Sun at the peak of solar activity. In addition, discoveries made from NASA's heliophysics missions during this time are also shared with the public.
• "World Meteorology Day" -- A celebration will be held on Thursday, 21 March 2013 for World Meteorology Day. This day is designated to celebrate the anniversary of the establishment of the World Meteorological Organization (WMO) on 23 March 1950. The WMO is an agency within the United Nations. This year's theme for World Meteorological Day 2013 is “Watching the weather to protect life and property." The 50 years of "World Weather Watch" will be celebrated. The "World Weather Watch" which is a WMO program that involves a worldwide system for observing and exchanging meteorological and related observations.
• "World Water Day" -- Friday, 22 March 2013, has been designated by the United Nations (UN) as the annual World Water Day. In reflection of 2013 being the "International Year of Water Cooperation," the theme for this year's World Water Day is also dedicated to the theme of cooperation around water.. [UN-Water]
• A name change for one of national environmental prediction centers -- Recently, the Hydrometeorological Prediction Center (HPC), which is one of the nine centers in the National Weather Service's National Centers for Environmental Prediction Centers (NCEP), was renamed the Weather Prediction Center (WPC). The change in name, which took place two weeks ago, is meant to provide a better description of the Center's mission that involves the production of quantitative precipitation forecasts, short- and medium-range forecast graphics and discussions, winter weather products and other guidance information for the state of the atmosphere across the nation and surrounding areas out to 14 days. Forecasts or outlooks for longer lead times continue to be the mission of NCEP's Climate Prediction Center. (Editor's note: Currently, products that were available from the older HPC websites can still be accessed. EJH) [NOAA Weather-Ready Nation]
• Marine and tropical weather statements -- This week's Supplemental Information...In Greater Depth identifies those National Weather Service Forecast Centers that monitor the weather, prepare weather forecasts, and issue event-specific warnings or advisories for marine and coastal interests. The terminology used to identify the particular warnings, watches and advisories for marine interests and for tropical weather events is also discussed.

Ocean in the News:

• Eye on the tropics --- Two tropical cyclones traveled across the western South Pacific Ocean basin last week.
  Tropical Cyclone Sandra, which had briefly become a major category 3 tropical cyclone on the Saffir-Simpson Scale over the previous weekend, traveled southward over the South Pacific between New Caledonia and Australia. early last week. By late in the week, this tropical cyclone weakened and dissipated. Additional information on Tropical Cyclone Sandra including satellite imagery can be obtained from the NASA Hurricane Page.
  A second tropical cyclone, which became Tropical Storm Tim developed near the midpoint of last week over the Coral Sea to the northeast of Australia. Tim traveled to the east-southeast during the late week before turning toward the south over the past weekend. This system generated tropical storm-force winds (39-74 mph). Forecasts indicate that Tim would weaken as it turns to the west and heads for the coast of Australia early this week. The NASA Hurricane Page has satellite images and additional information on Tropical Storm Tim.
• Review of global weather and climate for February 2013 -- Using preliminary data collected from the global network of surface weather stations, scientists at NOAA's National Climatic Data Center have determined that the combined global land and ocean surface temperature for February 2013 was the ninth highest for any February since global climate records began in 1880. The average global ocean surface temperature for February was the eighth highest on record, while the global land surface temperature for February 2013 was eleventh highest. The scientists claim that ENSO-neutral conditions that continued through the month were responsible for below average sea surface temperatures across the equatorial surface waters of the eastern and central Pacific, but above average sea surface temperatures across the equatorial Atlantic, Indian, and western Pacific Oceans. [State of the Climate/NCDC]
• Sharks and rays granted protection from an international agency -- During the last week, members of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreed to agreed to increase protection for five commercially-exploited species of sharks and manta rays at the 16th Meeting of the Conference of the Parties to CITES being held in Bangkok, Thailand. The oceanic whitetip shark, three species of hammerhead sharks (scalloped, smooth, and great), the porbeagle shark and manta rays were added to a list that means increased protection, but still allows legal and sustainable trade. [NOAA Fisheries]
• Highlighting the green sea turtle -- The NOAA Fisheries produced a "Green Turtle Fact Sheet" that describes the green turtle and its habitat, as well as a description of how the turtle received its name. [NOAA National Ocean Service]
• A "dirty blizzard" could explain missing oil from Gulf spill -- The Deep-C Consortium that are group of scientists from Florida State University, Eckerd College, the University of South Florida and Georgia Institute of Technology recently reported that a massive sedimentation event called a "dirty blizzard" appears responsible for the disappearance of a portion of the 200 million gallons of spilled oil following the 2010 Deepwater Horizon spill. Apparently, the oil acted as a catalyst for plankton and other surface materials to clump together and fall to the sea floor in a massive sedimentation event. The researchers used thorium, lead and radiocarbon isotopes in addition to DNA analyses of sediments to arrive at their conclusions. [Florida State University]
• An All-Hazards Monitor -- This Web portal provides the user information from NOAA on current environmental events that may pose as hazards such as tropical weather, drought, floods, marine weather, tsunamis, rip currents, Harmful Algal Blooms (HABs) and coral bleaching. [NOAAWatch]
• Global and US Hazards/Climate Extremes -- A review and analysis of the global impacts of various weather-related events, to include drought, floods and storms during the current month. [NCDC]
• Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Loss of Louisiana's Coast

According to the Louisiana Coastal Wetlands Conservation and Restoration Task Force, Louisiana has been losing its coastal wetlands (bayous, marshes, and swamps) to the waters of the Gulf of Mexico at an alarming rate of about 65 to 100 square km (25 to 38 square mi) per year for the past several decades. This loss adversely affects fisheries in the Gulf of Mexico and makes the coastal zone more vulnerable to storm surges such as that produced by Hurricane Katrina in August 2005. Since the early 1930s, the state's coastal wetlands have shrunk by an area equivalent to the state of Delaware. According to USGS estimates, an additional 1800 square km (700 square mi) could be lost by mid-century. The price tag for reversing this trend, restoring some marshes, and protecting the remaining 15,000 square km (5800 square mi) of wetlands could top $14 billion and take decades to complete. Many people argue that the value of Louisiana's coastal wetlands is well worth the expense.

As much as 75% of the fish and other marine life in the northern Gulf of Mexico depend on Louisiana's coastal wetlands. The wetlands are a nursery for commercially important catches of shrimp, crawfish, blue crab, and oysters. It is a food source for larger fish including yellow fin tuna, red snapper, and swordfish. In 2003, about three-quarters of the nation's fish and shellfish catch by weight came from Louisiana's waters. In addition, the wetlands are a stopover for millions of birds migrating between North and Central/South America. Furthermore, wetlands and associated barrier islands protect the ports, buildings, and other coastal zone structures from storm surges. Wetlands are particularly important in buffering the levees surrounding New Orleans, much of which is below sea level.

Many factors contribute to the loss of Louisiana's coastal wetlands. Thousands of kilometers of pipelines transporting oil and natural gas through the marshes plus the extensive network of navigation channels allow saltwater to intrude the wetlands. Increased salinity of the originally fresh or brackish waters kill wetland grasses, shrubs, and other vegetation that anchor soil in place. The canals also allow tidal currents to flow farther inland, accelerating erosion of wetland soils. The most important factor, however, is the consequence of flood control structures (levees) constructed along the banks of the Mississippi River. Levees constrict the flow of the river so that waters and suspended sediment discharge rapidly into the Gulf. Deprived of a continuous input of sediments and vegetation-supporting nutrients, existing sediments compact, wetlands subside and Gulf waters invade the wetlands. With the anticipated continued rise in sea level due to global climate change (discussed in Chapter 12 of your textbook), erosion of Louisiana's coastal wetland may accelerate in the future.

Plans to reverse the loss of Louisiana's coastal wetlands (the Coast 2005 plan and the Louisiana Coastal Area plan) seek to restore the structure and function of coastal wetlands. One proposal is to breach some levees along the lower Mississippi. This partial diversion of the Mississippi would increase the supply of sediments to the wetlands. Closing or installing locks on some navigation canals would reduce saltwater intrusion. In addition, dredged sediment would be used to re-build wetlands and restore barrier islands.

Concept of the Week: Questions

1. The most important factor contributing to erosion of Louisiana's coastal wetlands is [(saltwater intrusion)(levees along the banks of the Mississippi River)].
2. Global climate change that is accompanied by a rise in sea level is likely to [(accelerate)(have no effect on)] the rate of erosion of Louisiana's coastal wetlands.

Historical Events:

• 20 March 1866...The immigrant ship Monarch of the Seas left Liverpool, England, but was never seen again. The ship with 738 people was officially declared "lost" after 130 days. A message in a bottle was found at Plymouth, supposedly sent by a passenger. In July, wreckage was found around the Dingle coast in Southern Ireland.
• 20 March 2000...A large iceberg measuring approximately 170 mi by 25 mi calved off Antarctica's Ross Ice Shelf near Roosevelt Island. The iceberg was approximately 2.5 times the size of New York's Long Island. (Accord's Weather Guide Calendar)
• 22 March 1778...Captain James Cook of the British Royal Navy sighted Cape Flattery, in present day Washington State.
• 22 March 1999...Tropical Cyclone Vance produced Australia's highest measured wind speed of 166 mph at Learmonth, West Australia. Gusts reaching 185 mph were estimated in the eyewall in the Exmouth Gulf. All homes in the village of Exmouth were either damaged or destroyed. (Accord's Weather Guide Calendar)
• 24 March 1955...The first seagoing oil drill rig (for drilling in over 100 feet of water) was placed in service by the U.S. company C.G. Glasscock Drilling Co. The rig was able to drive piles with a force of 827 tons and pull a pile with the force of 942 tons. (Today in Science History)
• 24 March 1989...The tanker Exxon Valdez grounded on a reef in Prince William Sound, AK, spilling 10.1 million gallons of crude oil, resulting in the worst oil spill in U.S. history. Coast Guard units responded and prevented the entire cargo from spilling, cleaned up the oil which did spill, and conducted an investigation into the causes of the accident. The spill provided the impetus for the passage of the Oil Protection Act in 1990. (US Coast Guard Historians Office)

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Prepared by AMS DS Ocean Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2013, The American Meteorological Society.