WEEKLY WATER NEWS

DATASTREME WES WEEK TEN: 31 March-4 April 2008

Water in the News:

(Thurs.) "Nautical Charts" is unveiled as multimedia educational tool -- NOAA's National Ocean Service recently unveiled a multimedia educational program for third through fifth grade called Nautical Charts that is designed to teach youngsters about charting and navigation. [NOAA News]
(Thurs.) Giant ocean eddy found off Australia -- An oceanographer with Australia's Commonwealth Scientific and Industrial Research Organisation has used satellite data and imagery to monitor the evolution of a giant 300-km wide eddy of cold water off the New South Wales coast for six months. [CSIRO]
(Tues.) Young arctic ice found -- Images obtained from NASA satellites indicate that the polar sea ice found in the Arctic Ocean near the end of the winter season appears to be younger than during previous winters. This current winter follows the 2007 summer in which the ice had reached a record minimum areal coverage. [NASA Earth Observatory]
(Tues.) Ice shelf disintegration monitored from space -- In late February, images made by the MODIS sensors on NASA's Terra and Aqua satellites shows the rapid disintegration of the Wilkins Ice Shelf on the Antarctic Peninsula. [NASA Earth Observatory] Additional detail was provided by the images obtained from the Taiwanese Formosat-2 satellite. [NASA Earth Observatory] Researchers at the National Snow and Ice Data Center warn that the collapse of the Wilkins Ice Shelf appears to be associated with climate change in an area of the continent experiencing rapid increases in temperature. [EurekAlert!]
(Tues.) Pollutants studied in ice-free Arctic regions -- Researchers from NOAA’s Pacific Marine Environmental Laboratory and colleagues are participating in a program called the International Chemistry Experiment in the Arctic Lower Troposphere (ICEALOT), which is part of a larger international program being conducted during the International Polar Year called POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport). The ICEALOT science team is onboard the Woods Hole Oceanographic Institute's Reseach Vessel Knorr, taking air samples off the U.S. Atlantic coast, before heading for the Greenland, Barents and Norwegian Seas. [NOAA News]
Eye on the Tropics -- Tropical cyclone (hurricane) activity continued across the tropical waters of the South Indian Ocean last week, during austral autumn. Tropical Cyclone Pancho formed at the start of last week over eastern sections of the South Indian Ocean. This cyclone, which intensified to become a Category 2 cyclone on the Saffir-Simpson Scale, traveled to the south-southeast, approaching the western coast of Australia on this past Saturday, before dissipating. A satellite image from the Japanese MTSAT satellite late last week shows a well formed eye surrounded by the characteristic bands of clouds surrounding Pancho. [NOAA OSEI] A visible image obtained from the Atmospheric Infrared Sounder (AIRS) on NASA's Aqua satellite shows the clouds surrounding a weakening Tropical Cyclone Pancho late last week. [NASA Hurricane Page]
In the western sections of the South Indian Ocean, Tropical Cyclone Lola dissipated east of Madagascar at the start of last week. An infrared image obtained from the Atmospheric Infrared Sounder (AIRS) on board NASA's Aqua satellite shows the temperatures of the tops of the clouds surrounding Tropical Cyclone Lola. [NASA Hurricane Page]
Monitoring floods from space -- A comparison of images obtained last week by the MODIS sensor on NASA's Terra satellite with images made within the last six weeks show the extent of flooding in several far-flung areas of the world:
- In the Southcentral United States, where several tributaries of the lower Mississippi River have flooded by rain from numerous storms. [NASA Earth Observatory]
- In Namibia, a nation in southern Africa, where flooding occurred because of rain in nearby Angola. [NASA Earth Observatory]
- In western China, where the Huang (Yellow) River flooded due to the formation of ice dams because of slow ice melt. [NASA Earth Observatory]
Becoming AWARE -- During this coming week of 31 March -4 April 2008, New Mexico will conduct their Severe Weather Awareness Week. These weeks are usually scheduled before the onset of the severe weather season in that particular state. In addition, Washington State observes an All Hazards Awareness Month during April. If you live in any of these states, you should take time to become familiar with the various public affairs announcements issued by your local National Weather Service Office. In upcoming weeks, other states will observe Severe Weather Awareness weeks.
The State of Hawaii and the National Weather Service Office in Honolulu have declared April as Tsunami Awareness Month in the Aloha State. Their announcement commemorates the destructive tsunami on 1 April 1946 that cost 159 people their lives. Several events and programs have been scheduled during this month to help educate and inform Hawaiians of the dangers associated with tsunamis, an ocean wave that is generated by a submarine earthquake, volcano or landslide and can travel great distances. The National Weather Service Office is also hosting the International Tsunami Information Center in conjunction with the Intergovernmental Oceanographic Commission of UNESCO. [International Tsunami Information Center]
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: Water in Microclimates

Water is an important component of Earth's planetary-scale climate system, playing a key role in the global radiation balance (e.g., the greenhouse effect) and large-scale transport of heat (e.g., latent heat transfer and ocean currents). The global climate system exhibits considerable spatial variability so that Earth is a mosaic of many climate types and water is often an important factor in distinguishing between individual climates. Hence, for example, the climate of a desert differs from that of a rainforest primarily because of differences in precipitation totals and potential evaporation rate.

Climate (long-term average atmospheric conditions) also varies on smaller spatial scales. Here, we consider examples of how the local water and heat energy budgets vary on the scale of microclimates, having horizontal dimensions from less than 1 m to 100 m (3.3 ft to 330 ft) and vertical dimension from Earth's surface to an altitude of 100 m (330 ft).

All other factors being equal, afternoon air temperatures tend to be lower over an irrigated farm field than over a non-irrigated field. Where soils are wet, more of the available heat is used to evaporate water (latent heating) leaving less to raise the temperature of the soil surface and overlying air (sensible heating). In the Northern Hemisphere, snow tends to persist longer and the growing season is shorter on the shaded north- and east-facing hill slopes (facing away from the sun) than on south- and west-facing slopes (facing the sun). In portions of the Rocky Mountains, the sunnier, drier, and warmer south-facing slopes are sparsely vegetated by grasses, ponderosa pine, and juniper. Meanwhile, dense stands of fir and spruce grow on the shaded, moist, and cooler north-facing slopes.

Trees, sand dunes, buildings and other obstacles slow the wind and reduce the wind's ability to transport material (including soil particles) in suspension. Farmers take advantage of this effect by constructing shelterbelts (or "windbreaks") that reduce wind erosion of soil and modify the microclimate. A shelterbelt may consist of a fence or multiple rows of trees or bushes planted upwind of an agricultural field--usually oriented perpendicular to the prevailing wind direction. In the winter, snow-bearing horizontal winds slow as they encounter a shelterbelt. The wind's ability to transport snow diminishes and snow accumulates on the field immediately downwind of the shelterbelt. The air spaces within a snow cover make it a relatively poor conductor of heat so that the snow cover protects the underlying soil from deep penetration of subfreezing temperatures. In areas where winter wheat is grown, the snow cover protects the dormant plants from potentially damaging fluctuations in soil temperature. Snow trapped by shelterbelts also increases the local supply of soil moisture that becomes available during the spring thaw. Furthermore, slowing the wind reduces the evaporation of soil moisture. Significant increases in crop yields can be attributed to the microclimatic effects of shelterbelts.

Climatic contrasts are also evident between forested and non-forested areas. Wind speed diminishes considerably within a forest--as much as 60% to 80% at a distance of only 30 m (100 ft) into a deciduous forest. Weaker winds coupled with reduced solar radiation reaching the forest floor (due to the forest canopy) decreases the amount of evaporation from the forest floor. However, the relatively high rate of transpiration by forest vegetation more than compensates for the reduction in evaporation from the forest floor. Overall, the air in a forest tends to be somewhat more humid than the air over a nearby non-forested area. Even tall field crops such as corn have a similar effect on the microclimate.

Concept of the Week: Questions

In the Northern Hemisphere, snow is likely to persist longer on the shaded [(north-) (south-)] facing slope of a hill.
The relatively high humidity in forested areas is primarily the result of relatively high [(precipitation) (evaporation) (transpiration)] occurring in forested areas.

Historical Events:

31 March 2000...The water temperature of Lake Erie at Buffalo, NY was 39 degrees Fahrenheit on the last day of March, tying the maximum temperature for the date with that of 1998. Ice was present in 61 of 74 years on the 31^st, but this was third year in a row with open water. (Accord's Weather Guide Calendar)
1 April 1946...The Scotch Cap Lighthouse on Unimak Island in Alaska's Aleutian Islands was shaken by two earthquakes in a 27 minute span, then obliterated by a tsunami wave. The entire five-man crew was killed and the lighthouse antenna (105 ft above sea level) was washed away. Some debris was found 115 ft above sea level. The tsunami that propagated across the Pacific Ocean was responsible for more than 165 fatalities and over $26 million in damage. Many of the casualties were on the Hawaiian Islands, especially in Hilo on the Big Island. This tsunami was responsible for the development of the current Pacific Tsunami Warning System. (University of Washington) (Accord's Weather Guide Calendar) (US Coast Guard Historian's Office)
2 April 1958...One of the most destructive coastal storms in years battered New England (31 March-3 April). Some beaches between Portland, ME and Cape Cod, MA were eroded by approximately 50 ft. Miles of sea walls and bulkheads were either breached or demolished. Many beachfront cottages in Massachusetts, New Hampshire and Maine were sandblasted. (Accord's Weather Guide Calendar)
2 April 1997...An intense winter storm slammed the Maritime Provinces. Freezing rain knocked out power to more than 4,000 homes on Prince Edward Island. (The Weather Doctor)
3 April 1982...Wind-driven ice from Lake Winnebago in east central Wisconsin piled to 40-ft heights on the lake's eastern shoreline, damaging buildings in the Stockbridge area. Winds reached 80 mph across Wisconsin. (Accord's Weather Guide Calendar)
4 April 1933...Pigeon River Bridge, MN reported 28 in. of snow, which established the state 24-hr snowfall record. (4^th-5^th) (The Weather Channel)
4 April 1973...Sandia Crest, NM reported a snow depth of 95 in., a record for the state of New Mexico. (The Weather Channel)
4 April 1987...New England was in the middle of its second heavy rainstorm in 5 days. This was the same storm that produced record snows in the Appalachians. This storm dumped 4 to 7 in. of rain over the area and this, combined with snowmelt and rivers already at bankfull, produced record flooding, especially in Maine, where 2300 homes were flooded with 215 totally destroyed. Record water levels were reached at many dams. Damage in the state alone reached $100 million. (The National Weather Summary) (Storm Data) (Intellicast)
4 April 2004...Runoff from 8 to 12 inches of rain that fell over the Davis Mountains of west Texas led to the cracking and collapse of the I-20 bridge over Salt Draw near Toyah. The interstate was closed thanks to a timely flash flood warning. However, five indirect fatalities occurred in a multi-vehicular accident on the US-285 detour near Pecos. (Accord's Weather Guide Calendar)
5 April 1926...A reported 0.65 in. of rain fell in one minute at Opid's Camp, CA (Intellicast)
5 April 1987...After days of heavy rain that drenched eastern New York State with 5 to 8 in., a New York State Thruway bridge over Schoharie Creek collapsed just west of Amsterdam, New York. Ten people died when their vehicles plunged into the flood-swollen creek either with or shortly after the bridge collapse. (Intellicast)
6 April 1900...The worst flood on record in the Brazos River watershed of Texas occurred from the 5^th through the 8^th. An average of 17 in. of rain fell over a 7000-square mi area, while 33 in. fell on Turnersville and an estimated 30 in. at Hearme since the rain gage overflowed at 24 in. More than 30 deaths resulted from the floods. (Accord's Weather Guide Calendar)
6 April 1987...Rain and melting snow caused flooding from New England to Ohio. Flooding in the Merrimack Valley of Massachusetts was the worst in fifty years, causing $42 million in damage. (The National Weather Summary) (Storm Data)

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