WEEKLY WATER NEWS

DataStreme WES Week Nine: 3-7 November 2008

Opportunity for Teachers: The National Ocean and Atmospheric Administration's (NOAA) Teacher at Sea 2009 Field Season program is now accepting applications until 31 December 2008. Gain your "sea legs" and first-hand experience in one week to one month voyages. For more information, or to apply, see http://teacheratsea.noaa.gov.
Applications for a prestigious scholarship invited -- NOAA is accepting applications from qualified college undergraduate students interested in pursuing degrees in ocean and atmospheric sciences and education to the Ernest F. Hollings Undergraduate Scholarship. As many as 100 undergraduates could each receive up to $29,050 for their academic studies related to NOAA science, research, technology, policy, management, and education activities. Applications will be accepted through 30 January 2009. [NOAA News]

Water in the News:

Eye on the tropics -- The past week had relatively little tropical cyclone activity:
- In the eastern North Pacific, the sixteenth named tropical cyclone of the 2008 season formed on Sunday off the southwest Mexican coast. This system, called Tropical Storm called Polo, was projected to move westward.
- In the North Indian Ocean basin, Tropical Storm Rashmi traveled northward across the Bay of Bengal and made landfall early last week in Pakistan. An image made from data collected by the scatterometer on NASA's QuikSCAT shows the counterclockwise circulation of the winds around the center of Tropical Storm Rashmi over the northern Bay of Bengal. [NASA Earth Observatory] For additional information and satellite images on Tropical Storm Rashmi, consult the NASA Hurricane Page.
Flooding from tropical weather systems captured from space -- Images generated from data collected by NASA's Tropical Rainfall Measuring Mission (TRMM) satellite can provide an indication of the heavy precipitation that falls from tropical weather systems over data sparse areas, such as the oceans or over uninhabited regions. Recent images were made of:
- Rainfall totals over Yemen, the Gulf of Aden and the Arabian Sea during the third week of October due to Tropical Cyclone 3 that approached the typically arid country of Yemen. [NASA Earth Observatory]
- Rainfall anomalies (differences in actual and average rainfall totals) for October over Central America following the passage of Tropical Depression 16 in the western Caribbean Sea. [NASA Earth Observatory]
Contrasting hurricane theories evaluated -- Researchers at NOAA's Geophysical Fluid Dynamics Laboratory, the University of Wisconsin - Milwaukee and the University of Miami's Rosenstiel School of Marine and Atmospheric Science have analyzed more than 50 years of hurricane data in an attempt to determine if the relationship between sea surface temperature (SST) and seasonal Atlantic hurricane activity are caused by local and isolated variations in SST of the Atlantic basin or by SST variations in the Atlantic "relative" to the rest of the tropics. [EurekAlert!]
Ike produced underwater damage in Texas -- An underwater survey conducted by scientists from The University of Texas at Austin of the Bolivar Roads inlet between Galveston Bay and the Gulf of Mexico within two weeks following this fall's Hurricane Ike indicates that the hurricane reshaped the seafloor and apparently carried a large quantity of sand and sediment into the Gulf. [University of Texas at Austin]
Cruise ship to house refugees from Ike -- State emergency management officials in Texas are attempting to request funding from FEMA (Federal Emergency Management Agency) to use the aging cruise ship Regal Express to house people displaced from the Galveston and Houston metropolitan areas due to the landfall of Hurricane Ike in September. [USA Today]
Disaster aid works get help from satellites -- Workers who are attempting to provide humanitarian aid in Honduras in the wake of devastating flooding and mudslides following a tropical depression in mid October have been using images of the disaster area obtained from the European Space Agency's Envisat satellite. [ESA]
Conditions initiating erosion are identified -- Researchers at Virginia Tech College of Engineering have determined that turbulence spikes in the fluid flow within the atmosphere or in a water body are responsible for initiating erosion by dislodging particles on the land surface or within the water and making these particles mobile. [EurekAlert!]
Record rate of Arctic sea ice thinning noted -- Scientists at the United Kingdom's University College London conclude that their measurements of Arctic sea ice from 2002 to 2008 using radar altimeter data from the European Space Agency's Envisat satellite indicate that the sea ice thickness across large sections of the Arctic decreased a greater rate last winter than over the previous five winters. [ESA]
Melt ponds detected on Greenland Ice Sheet -- An image of a portion of the Greenland Ice Sheet made last August from the MODIS sensor on NASA's Terra satellite shows ponds of melt water on the ice along the northeast coastal region of the island. [NASA Earth Observatory]
The deadly 2004 Indian Ocean tsunami was not the first -- An international team of researchers recently reported that the deadly and devastating Indian Ocean tsunami of December 2004 was not the first of similar magnitude to hit the region, claiming that deposits from Indonesia indicate three previous major tsunamis in the last 1200 years, with the last between 1300 and 1400 CE. [EurekAlert!] Similar findings were also found on a barrier island off the west coast of Thailand. [EurekAlert!]
Salmon tracked from the Rockies to Alaska -- Scientists participating in the Pacific Ocean Shelf Tracking Project, a part of the Census of Marine Life have developed and used a new miniature tagging system that can track juvenile salmon as they migrate from the headwaters of the Columbia River in the northern Rocky Mountains out the Pacific Ocean and then north to the Alaska coast. [EurekAlert!] In another part of the study, researchers from Oregon and British Columbia determined that the survival of juvenile salmon and steelhead who migrate from where they were spawned near the headwaters of the Columbia and Fraser Rivers was remarkably similar despite the difference associated with dams on the Columbia, but no dams on the Fraser. [EurekAlert!]
Subtropical Atlantic becoming saltier -- Recent research at the United Kingdom's Met Office Hadley Centre and Walker Institute for Climate System Research suggests that increasing salinity of the subtropical Atlantic Ocean basin is likely due to decreased precipitation and runoff from the land surface and increased evaporation, both at least partially affected by human activity in the sub-tropical latitudes. [UK Met Office]
Antarctic glaciers probed -- ICECAP (Investigating the Cryospheric Evolution of the Central Antarctic Plate), an international team of scientists from the United States, the United Kingdom and Australia will explore East Antarctica's Aurora and Wilkes Subglacial Basins, a large uncharted region of ice-buried lowlands, in an attempt to determine how the region had responded to past climate change and to determine future changes in sea level that could occur with projected future changes in climate. [EurekAlert!]
NOAA satellite reaches landmark -- Two people were recently rescued from a downed airplane in the northern Cascades of western Washington State recently because of their distress signal was picked up by one of the NOAA satellite that is part of the Search and Rescue Satellite-Aided Tracking system called COSPAS-SARSAT. This rescue was the 6000th rescue of downed pilots, shipwrecked mariners, and stranded hikers in the United States since this program began 26 years ago. [NOAA News]
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, including drought, floods and storms during the current month. [NCDC]
Global Water News Watch -- Other water news sources can be obtained through the SAHRA Project at the University of Arizona [SAHRA Project]
Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Seiche

You probably remember as a child agitating the bath water so that it sloshed back and forth in the tub. (If you never did this as a child, there's still time.) You produced a seiche, a phenomenon first studied in Lake Geneva, Switzerland in the 1700s. A seiche (pronounced "say-sh") is a rhythmic oscillation of water in an enclosed basin (e.g., bathtub, lake, or reservoir) or a partially enclosed coastal inlet (e.g., bay, harbor, or estuary). With this oscillation, the water level rises at one end of a basin while simultaneously dropping at the other end. A seiche episode may last from a few minutes to a few days.

A seiche is a standing wave. Whereas wind-driven waves (pages 181-182 in your DataStreme WES textbook) are progressive in that they propagate through a body of water, standing waves are stationary. With progressive waves, crests and troughs travel along the water surface but with standing waves, crests alternate vertically with troughs at fixed locations. For both progressive and standing waves, the restoring force is gravity.

With a typical seiche in an enclosed basin, the water level near the center does not change at all although that is where the water exhibits its greatest horizontal movement; this is the location of a node. At either end of an enclosed basin, vertical motion of the water surface is greatest (with minimal horizontal movement of water); these are locations of antinodes. The motion of the water surface during a seiche is somewhat like that of a seesaw: The balance point of the seesaw does not move up or down (analogous to a node) while people seated at either end of the seesaw move up and down (analogous to an antinode).

Go to the University of Delaware's Seiche Calculator at http://www.coastal.udel.edu/faculty/rad/seiche.html. Set the "Modal Number" to 1 and then press "Calculate" for a graphical simulation of a seiche in an enclosed basin.

Partially enclosed basins usually have a node located at the mouth (rather than near the center) and an antinode at the landward end. Go to the Seiche Calculator, set the "Modal Number" to 0.5 and then press "Calculate" for a simulation of a seiche in a basin open to the right. Furthermore, some basins are complex and have multiple nodes and antinodes; these can be simulated on the Seiche Calculator by selecting different values of "Modal Number" greater than one.

A seiche can be induced by wind, regional differences in air pressure, earthquakes, or tidal forces. For example, wind blowing persistently in the same direction down the long axis of a bay causes water to pile up at the downwind end of the bay. When the wind slackens, the water oscillates (as a seiche) back-and-forth from one end of the bay to the other until eventually the water calms to a horizontal surface. A line of thunderstorms moving eastward from Wisconsin in late May 1998 produced a seiche in Lake Michigan that killed several people by drowning at the southern end of the lake. Previous seiches have produced 8 to 10 ft waves on Lake Michigan. A tsunami generated a seiche in the harbor of Hilo, HI following a major earthquake in the Aleutian Islands on 1 April 1946.

The natural period of a seiche depends on the length and depth of the basin and generally ranges from minutes to hours: The period is directly proportional to basin length. For example, the natural period of a seiche in a small pond is considerably shorter than its period in a large coastal inlet. In addition, for the same basin, the natural period is inversely proportional to water depth; that is, the period shortens as water deepens. Using the Seiche Calculator, you may wish to experiment with different values of basin length and depth. Conversely, one can estimate the average depth of a lake by determining the period of the seiche and the length of the lake.

Usually a seiche in a lake or harbor is of little concern because the changes in water level are minor--often only a few centimeters. Under certain circumstances, however, a seiche may grow to great heights with serious consequences including flooding and damage to moored vessels. A seiche grows as a consequence of resonance, that is, when the period of the disturbance (e.g., wind, earthquake) matches the natural oscillation period of a specific basin. Recall again your youthful bathtub experience. By timing your rhythmic disturbance of the water to match the natural period of the tub (about one second), you were able to cause the seiche to build until the water splashed out of the tub and onto the floor. Through resonance, vibrations from the 1994 Northridge, CA earthquake caused swimming pools to overflow throughout Southern California. In bays open to the ocean, if the period of tidal forcing matches the natural period of the bay, resonance can greatly increase the tidal range.

Concept of the Week: Questions

Seiches are [(standing) (progressive)] waves.
The natural period of a seiche [(depends on) (is independent of)] the size of an enclosed basin.

Historical Events:

3 November 1927...The "Great Vermont Flood" began as a two-day rain of up to 9 inches put rivers in western New England over their banks. Somerset, VT was deluged with 8.77 inches of rain to establish a 24-hour record for the state. (3^rd-4^th) (The Weather Channel) (Intellicast)
4-5 November 1966...The River Arno surged above flood stage and caused irreparable damage to much of the architectural and art treasure of Florence, Italy. Millions of historical library volumes were either damaged or destroyed. More than 15,000 vehicles were also destroyed. Roughly two-thirds of Florence was flooded, 113 people died and 30,000 were made homeless by the flooding on both the Arno and Po rivers. (Accord Weather Calendar) (Wikipedia)
5 November 1977...A slow moving storm produced five to nine inch rains across northern Georgia causing the Toccoa Dam to burst. As the earthen dam collapsed, the waters rushed through the Toccoa Falls Bible College killing three persons in the dorms. Thirty-eight persons perished at a trailer park along the stream. Eighteen bridges were washed out in Madison County. (David Ludlum)
5 November 1987...Heavy rains in California's Death Valley National Park washed out many park roads. As much as 1.20 in. of rain fell at Scotty's Castle, compared with the annual rainfall average of 2.28 in. Up to 8000 people attending a recreational encampment were stranded. (Accord Weather Calendar)
6 November 1994...Downtown San Francisco, CA was drenched with 6.19 in. of rain in 24 hrs to set an all-time record for the city.
6-13 November 1969...Severe ice storm between Quebec City and Manicouagan River power dams in Quebec caused over $1.5 million damage to transmission lines and towers. Over 30 transmission towers under construction were brought down. (The Weather Doctor)
8 November 1876...Two days of rain dumped 4.9 in. on Fredericton, New Brunswick. The rail line near Lawrence Station was washed out causing the derailment of the morning St. John-Fredericton run. (The Weather Doctor)
8 November 1914...On this date the longest "official" rain-free time span on record for the U.S. of 767 days ended in Bagdad, CA. Some meteorologists question the accuracy of this record kept by railroad employees at that time. (Accord Weather Guide Calendar)
9 November 1913...The "Freshwater Fury," a rapidly deepening extratropical cyclone, caused unpredicted gales on the Great Lakes. Seventeen ships, including eight large ore carriers on Lake Erie sank drowning 270 sailors. Cleveland, OH reported 17.4 in. of snow in 24 hrs, and a storm total of 22.2 in., both all-time records for that location. During the storm, winds at Cleveland averaged 50 mph, with gusts to 79 mph. The storm produced sustained winds of 62 mph at Port Huron, MI, wind gusts to 80 mph at Buffalo, NY and buried Pickens, WV under three feet of snow. (9^th-11^th) (David Ludlum) (The Weather Channel)
9 November 1932...An unnamed hurricane struck Cuba, with winds reaching approximately 210 mph at Nuvitas. However, a storm surge was the main killer of 2500 of the 4000 residents of Santa Cruiz del Sur. Essentially no storm records exist, as the observer drowned, with records and instruments washed away. (Accord Weather Guide Calendar)
9-11 November 2001...More than the average month's total (3.7 inches) of heavy rains fell on Algiers, Algeria in just a few hours. The resulting massive floods and mudslides devastated northern Algeria and killed more than 700 people causing nearly $300 million worth of damage. (The Weather Doctor)