28 February-4 March 2011

ITEMS OF INTEREST

• A change in meteorological seasons --
  Monday, 28 February 2011, marks the end of meteorological winter in the Northern Hemisphere, which by convention, is the three-month interval of December, January and February. The following day (1 March 2011) represents the beginning of boreal meteorological spring, the three month interval of March, April and May. At the same time, summer in the Southern Hemisphere ends and autumn begins.
• Leap years and calendars --
Since the Earth completes one orbit around the Sun in 365.2422 days, calendars based upon integer days must be adjusted every few years so that recognizable events, such as the occurrence of the vernal equinox, do not progress through the year. In the first century BC the Julian calendar was developed by Julius Caesar who decreed a calendrical reform with a 365-day year that involved the inclusion of an extra day to the end of February (the last month of the old Roman year). However, an additional reform was instituted by Pope Gregory XIII in 1572 that included the requirement that only those centurial years divisible evenly by 400 would be leap years, while the other centurial years (e.g., 1800 and 1900) would not.
The National Climatic Data Center recommends that the climate normals for 28 February be used also for 29 February in a leap year.
• Alaskan climate science center is dedicated --
During the last week, officials from the US Department of Interior and the University of Alaska, Fairbanks dedicated the Alaska Climate Science Center in Anchorage as the first of eight regional climate science centers the Interior Department is establishing throughout the nation in collaboration with regional host research institutions. [US Department of Interior]
• Viewing atmospheric circulation in three-dimensions --
Read this week's Supplemental Information.. In Greater Depth for information concerning the average circulation in the lower and upper troposphere.

CURRENT CLIMATE MONITORING

• Sea ice rings an island in the Kurils --
  A natural color image obtained two weeks ago from the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite shows the annual sea ice formation around Ostrov Shikotan, a volcanic island at the southern end of the Kuril chain in the western North Pacific Ocean between Japan and Russia's Kamchatka Peninsula. [NASA Earth Observatory]
• 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, fire weather, marine weather, severe weather, drought and floods. [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]

CLIMATE FORCING

• Polar stratospheric warm events may be triggered in tropics --
  Researchers running numerical simulations on the Whole Atmosphere Community Climate Model (WACCM) at the National Center for Atmospheric Research have found that the El Niño-Southern Oscillation (ENSO) and Quasi-Biennial Oscillation (QBO), two patterns in the tropical atmosphere, appear to affect the frequency of sudden stratospheric warming events (SSWs) in the Arctic stratosphere. [UCAR/NCAR]

CLIMATE AND THE BIOSPHERE

• Tiny marine creatures collected by famous Antarctic explorer used to monitor climate change --
  Researchers from the British Antarctic Survey are beginning to study bryozoans, tiny marine animals, collected in the Ross Sea by the British explorer Robert Falcon Scott in 1901 in an effort to understand the impact of future climate change. They have found that polar carbon sinks in Antarctica have been increasing over the last century. [British Antarctica Survey]
• Longer ragweed season linked to changing climate --
Researchers with the USDA's Agricultural Research Service and other research institutions across the nation report that recent changes in climate appear to be leading to longer ragweed seasons across the US and Canada. Some of the recent ragweed seasons in many locations are 30 days longer than prior to 1995. [ScienceDaily]

CLIMATE FORECASTS

• Modeling snowfall and climate change in the Colorado River headwaters --
  A team of scientists from the National Center for Atmospheric Research have been calibrating and verifying the output statistics from the Weather Research and Forecasting model (WRF) that they have been using to forecast the amount of snowfall that falls seasonally on the headwaters of the Colorado River. By incorporating a signal designed to simulate changes in climate between 2045 and 2055 into this model, they are starting to forecast future snowfall across this region for the next several decades. [UCAR/NCAR]
• Ancient megadroughts were common in Southwest and may happen again --
A researcher at the University of New Mexico and his colleagues claim that "megadroughts" lasting for several millennia were common across the Southwestern States during previous Pleistocene interglacial periods between 550,000 and 370,000 years ago. They foresee that projected increases in global temperature could result in a return to megadrought conditions in the Southwest. [USA Today]
• Warmer and drier climate across Southwest could increase number of duststorms --
Scientists with the U.S. Geological Survey and the University of California, Los Angeles who examined 20 years of climate, vegetation and soil measurements collected in southeastern Utah's Arches and Canyonlands National Parks have found a decline in perennial vegetation in grasslands and some shrub lands due to increases in temperature. The researchers warn that a projected warmer climate in the Southwest would lead to drier conditions that would further reduce perennial vegetation cover and result in increased duststorms across the region. [USGS Newsroom]

PALEOCLIMATE RECONSTRUCTION

• Lake sediment climate record portends future drought in Pacific Northwest --
  An analysis of a sediment core from one of Washington State's lakes indicates longer and more extreme wet/dry cycles in the climate of the Pacific Northwest since 4000 BCE. The researchers from the University of Pittsburgh, Columbia University's Lamont-Doherty Earth Observatory, Kent State University and Idaho State University report that the extreme periods in these wet/dry cycles have occurred since 1200 AD, which may be associated with changing El Niño/La Niña patterns. They warn that the region could experience longer and more intense dry seasons in the future as the El Niño/La Niña patterns intensify due to changing climate. [University of Pittsburgh]
• An ancient megadrought could provide lessons for the future --
An international team of researchers from the US, the United Kingdom, France and Norway compiled four dozen paleoclimate records for the last 50,000 years from sediment cores in Africa. They found evidence of widespread and intense megadroughts occurring in Africa and southern Asia between 17,000 to 16,000 years ago due to a change in the Afro-Asian monsoon circulation. This ancient catastrophic drought, which most likely had severe consequences for Paleolithic cultures, could be a harbinger of future droughts due to changing climate conditions. [NSF]
• Ancient global warming events documented in the Arctic --
Scientists from the United Kingdom's University of Southampton have been studying marine sediment cores to ascertain environmental changes that occurred in the Arctic during the Paleocene–Eocene Thermal Maximum (PETM), an exceptionally warm period in Earth history approximately 56 million years ago. At that time, global sea surface temperatures increased by 5 Celsius degrees, causing widespread extinction of many foraminifera types, while plankton from tropical latitudes migrated poleward. [National Oceanography Centre]
• Plankton found to be a key to free oxygen in early atmosphere --
Analysis of isotopes stored in rock samples approximately 500 million years ago has permitted a researcher at Ohio State University and his colleagues to demonstrate how plankton provided for the release of a burst of free oxygen into the Earth's atmosphere at that time. Their study also details how oxygen nearly vanished from Earth's ancient atmosphere early in the Cambrian Period, only to return at higher levels. [Ohio State University]

CLIMATE AND SOCIETY

• Reactions to "Climategate" continue --
  The unauthorized release of stolen e-mail messages between climate scientists in the US and the United Kingdom in late 2009 has been dubbed "Climategate." Some recent new developments include:
• No evidence of "Climategate" wrong-doing --
Acting on a request from a US Senator, the Inspector General for the US Department of Commerce conducted an independent review of emails stolen from the United Kingdom's Climatic Research Unit at the University of East Anglia, finding no evidence of impropriety by NOAA climate scientists or reason to doubt NOAA's handling of its climate data. [NOAA News]
• "Climategate" undermined global warming beliefs among TV weathercasters --
Researchers at George Mason University recently released the results of a survey of television weathercasters concerning their reaction to the news of "Climategate." The poll indicated that many of the politically conservative weathercasters, as well as more males than females, were skeptical about the occurrence of global warming. [George Mason University]
• Human health could be impacted within 30 years by climate change --
A panel of scientists attending last week's annual meeting of the American Association for the Advancement of Science unveiled new research that indicates how projected changes in climate over the next 30 years could increase exposure and risk of human illness originating from ocean, coastal and Great Lakes ecosystems. [NOAA News]
• Food safety could be affected by climate change --
A professor at Michigan State University and other experts recently warned that current changes in climate are affecting the safety of the world's food supplies and that food safety issues would worsen unless corrective action is taken soon. [Michigan State University]
• Website for human dimensions of climate change --
An interagency effort within the US federal government that included NOAA, the Bureau of Land Management and the US Forest Service, has resulted in a website called HD.gov (for HumanDimensions.gov) that provides users, such as natural resource managers, with information on the human dimensions on a variety of topics of interest such as climate change. [HD.gov]
• Earthweek --
Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

REPORT FROM THE FIELD -- George Rausch, an AMS DataStreme LIT Leader and a snow spotter for the North Webster (IN) National Weather Service Forecast Office, reported on this season's lake effect snow across southwestern Michigan and northern Indiana. Using a snowboard, he measured 78.33 inches from November through 20 February at his home in Benton Harbor, MI near Lake Michigan, which was more than 21 inches above normal. Two major lake effect events were responsible for this snowfall. He noted that this amount was more than the 64.25 inches of snow that had fallen to the same date last year. The bulk of the snow this year came between 5 January and 12 February when 58.7 inches fell. George also noted that South Bend, IN, approximately 30 miles south of Benton Harbor had received 98 inches or snow, or 38 inches above normal. Usually, Benton Harbor receives more lake effect snow than South Bend.

Concept of the Week: Tropospheric westerly winds, north and south

The theoretical existence of upper tropospheric jet stream winds were not confirmed until being encountered by World War II bomber pilots when heading west into strong headwinds at altitudes of approximately 30,000 feet (10,000 m). Wind speeds sometimes exceeded 170 mph causing their relatively slow, heavily laden aircraft to almost stand still. Subsequently, westerly jet stream winds were found to encircle the planet in midlatitudes of both hemispheres above regions of strong temperature contrasts.

The explanation for these winds involves atmospheric mass distributions and forces on a rotating planet. Air in tropical latitudes is warmed, rises and then flows poleward, both north and south. On a rotating planet, moving air is deflected by the Coriolis effect, to the right in the Northern Hemisphere (and left in the Southern). The greater the temperature differences between warm lower and cold higher latitudes, the stronger the air motions and the faster the jet streams. The vertical temperature patterns result in the highest wind speeds near the top of the troposphere.

So Northern Hemisphere air headed northward, deflected to the right ends up headed east, a "westerly wind." In the Southern Hemisphere, southward moving air, deflected left will also go east, as a westerly wind. These "rivers" of strong upper-level winds steer surface weather systems as they move generally eastward across midlatitudes. They also provide boosts for jet aircraft headed eastward with them, but need to be avoided for going west! Of course, the full story is complex as land (especially mountains) and water surfaces interact with the heating of the air and eddies form in the turbulent flows, so jet streams wander. And with them go the storms and the weather patterns that form our short-term climate.

Concept of the Week: Questions

(Place your responses on the Chapter Progress Response Form provided in the Study Guide.)

1. The Northern Hemisphere jet stream winds would be directed such that cold air is [(to the left),(to the right),(directly ahead)] of their forward motion.
2. In the Southern Hemisphere, the jet stream winds to be directed generally toward the [(south), (east), (west)].

Historical Events:

• 28 February 1900...A massive storm spread record snows from Kansas to New York State. The 18.7 inches of snow measured at Topeka, KS in 24 hours was the city's greatest 24-hour snowfall on record. (David Ludlum) (Intellicast)
• 28-29 February 1964...A world 12-hour rainfall record was set at Belouve, La Reunion Island in the western Indian Ocean when 52.76 inches of rain fell. World records for 9 hours and 18.5 hours were also set with 42.79 and 66.49 inches, respectively. (Accord's Weather Calendar) (The Weather Doctor)
• 28 February 1972...Unseasonably mild weather prevailed throughout the central US. Temperatures soared to 83 degrees in Kansas City, MO, setting an all-time high record for the month of February. (Intellicast)
• 28 February 1988...Unseasonably mild weather prevailed in the northwestern U.S. The afternoon high of 71 degrees at Portland, OR was a February record. (The National Weather Summary) (Storm Data)
• 29 February 1964...Thompson Pass, AK finished the month with 346.1 inches of snow, a record monthly total for the state of Alaska. (The Weather Channel)
• 1 March 1910...The deadliest avalanche of record in the U.S. thundered down the mountains near Wellington Station, WA sweeping three huge locomotive train engines and some passenger cars off the tracks, over the side and into a canyon, burying them under tons of snow. This train was snowbound on the grade leading to Stevens Pass. The avalanche claimed the lives of more than 100 people. The station house at Wellington was also swept away. (The Weather Channel)
• 1 March 1993...4.5 inches of snow fell at Dodge City, KS on this date to raise its seasonal snowfall total to 58.8 inches. This set a new all-time seasonal snowfall record for the city. The old record was 57.5 inches set back in the winter of 1911-12. (Intellicast)
• 2 March 1927...Raleigh, NC was buried under 17.8 inches of snow in 24 hours, a record for that location. Nashville, NC received 31 inches of snow. The average snow depth in the state of Carolina was fourteen inches. (The Weather Channel)
• 2 March 1947…The one-day record snowfall of 16 inches of snow buried Canada's capital city of Ottawa, Ontario. The storm left 28.7 inches of snow covering the Ottawa region. (The Weather Doctor)
• 2 March 1996...Another East Coast snowstorm deposited 4.6 inches of snow at Central Park in New York City to bring its seasonal snowfall total to 66.3 inches, breaking the old season snowfall record of 63.2 inches set in 1947-48. (Intellicast)
• 3 March 1896...The temperature in downtown San Francisco, CA fell to 33 degrees, which was the lowest ever for the city in March. (Intellicast)
• 3 March 1971...An extremely intense coastal storm blasted the northeastern US on this day and continued into the 4th. The barometric pressure dropped to 960 millibars (28.36 inches) at Worcester, MA for the lowest pressure ever recorded at the location. The same record was set at Concord, NH with a reading of 963 millibars (28.44 inches). Wind gusts 70 to 100 mph lashed eastern New England with major wind damage occurring. Tides ran 4 to 5 feet above normal resulting in extensive coastal damage and beach erosion. (Intellicast)
• 3 March 1994...A major coastal storm was in progress over the mid-Atlantic and the Northeast. The 8.7 inches of snow at Allentown, PA raised its seasonal snowfall to 69.2 inches for its snowiest winter ever. Boston's 8 inches pushed its seasonal snow to 89.5 inches for its snowiest winter as well. (Intellicast)
• 3 March 2003…The day's low temperature of 30 degrees below zero at Marquette, MI was the lowest temperature ever recorded in March in the city. (The Weather Doctor)
• 4 March 1953...Snow was reported on the island of Oahu in Hawaii. (The Weather Channel)
• 4-5 March 1899...Tropical Cyclone Mahina (the Bathurst Bay Hurricane) crossed Australia's Great Barrier Reef and generated produced the highest storm surge ever recorded: 13 m (42.6 ft) surge in Bathurst Bay. The Australian pearling fleet was destroyed, over 100 shipwrecks reported and 307 people killed. Minimum central pressure barometric pressure fell to an unofficial reading of estimated at 914 millibars (26.90 inches of mercury). (Accord's Weather Calendar) (The Weather Doctor)
• 5 March 1960...The greatest March snowstorm of record in eastern Massachusetts began to abate. The storm produced record 24-hour snowfall totals of 27.2 inches at Blue Hill Observatory, 17.7 inches at Worcester, and 16.6 inches at Boston. (The Weather Channel)
• 5 March 2000…The Twin Cities of Minneapolis and St. Paul, MN established a new record for the fewest number of days between 70-degree Fahrenheit temperature reading from the last date in the autumn to the first date in the spring, with only 113 days passed. The previous record was 131 days, while the average has been 175 days. (The Weather Doctor)
• 6 March 1900...A chinook wind blowing down the slopes of the Rockies through Havre, MT raised the temperature 31 degrees in just three minutes. (The Weather Channel)
• 6 March 1954...Florida received its greatest modern-day snowfall of record, with 4.0 inches at the Milton Experimental Station. Pensacola, FL equaled their 24-hour record with 2.1 inches of snow. (The Weather Channel)
• 6 March 1962...Forty-two inches of snow fell at Big Meadows, located in the mountains of Virginia, for a state record as part of the Great Atlantic Coast Storm of 1962. (Intellicast)
• 6 March 1971…The temperature at Palteau Rosa, Italy fell to 30.2 degrees below zero Fahrenheit, Italy's lowest temperature on record. (The Weather Doctor)

Return to DataStreme ECS website

Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2011, The American Meteorological Society.