27 February-2 March 2012

ITEMS OF INTEREST

• A change in meteorological seasons --
  Wednesday, 29 February 2012, 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 2012) 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.
• Ground broken for NOAA's National Water Center -- Last week a ground breaking ceremony marked the beginning of construction for NOAA's National Water Center on The University of Alabama campus in Tuscaloosa, AL. This Center, to be completed by mid-2013, is intended to strengthen the nation's water forecast capabilities through collaborative efforts between as many as 20 federal agencies and academia. [NOAA News]
• "Climate Data Guide" is launched -- A group of scientists at the National Center for Atmospheric Research (NCAR) recently launched the "Climate Data Guide," a new online portal to a variety of datasets available to climate scientists that include climate indices, observational reanalysis datasets and model diagnostics. [NCAR/UCAR AtmosNews]
• 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

• Clouds are found to be lowering from a satellite perspective -- Using cloud-top height data collected over a ten-year span (2000 to 2010) from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite, scientists at New Zealand's University of Auckland in have found that the global-average cloud heights appear to have been lowering by approximately one percent. The investigators claim the these results could have an important impact on global climate. [NASA JPL]
• Ozone sensor on new polar orbiting satellite activated -- NASA and NOAA scientists and engineers recently activated the Ozone Mapper Profiler Suite (OMPS) onboard NASA's Suomi National Polar-orbiting Partnership satellite (Suomi NPP). The OMPS, one of five new instruments onboard this satellite launched last October, will be monitoring the health of Earth's stratospheric ozone.[Editor's note: A display of the ozone thickness as measured by NASA satellites over a 30-yr span is displayed. EJH] [NOAA News]
• Airborne research program to monitor Earth system processes in 2012 -- As part of NASA's Airborne Science Program and its Earth system science research initiatives, the agency's fleet of research aircraft will be used as part field campaigns in the United States, Canada, Greenland, Europe, Asia and South America during 2012. These highly modified aircraft that can fly to altitudes of 70,000 feet will carry specialized sensors that will be capable of making high-resolution measurements of local phenomena and processes, such as ice sheet thickness, precipitation and air quality. [NASA Earth Mission]
• Tracking an ocean current off Australia --Oceanographers from Australia's by University of Technology Sydney and Commonwealth Scientific and Industrial Research Organisation (CSIRO) have been tracking an ocean current through the Bass Strait using instrumented deep-diving ocean "gliders" that are being deployed by Australia's Integrated Marine Observing System. This ocean current flows through the Bass Strait separating Tasmania and New South Whales in southern Australia. [ CSIRO 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, 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

• New map of Earth's forest heights released -- Scientists from NASA's Jet Propulsion Laboratory, the University of Maryland, College Park and Woods Hole Research Center have recently produced an accurate, high-resolution global map detailing forest heights using data collected by the ICESAT/GLAS, MODIS and TRMM sensors onboard NASA's fleet of satellites. The researchers hope that their map will improve their understanding of Earth's forest habitats and the role that the forests play in Earth's carbon cycle. [NASA JPL]
• Smog particles draw in gases --Researchers from the University of California-Irvine, Portland State University and the US Energy Department's Pacific Northwest National Laboratory have found that atmospheric gases can be absorbed into airborne smog particles where they remain. These researchers claim that their findings could explain why current air pollution models such as those used by the US Environmental Protection Agency and California air regulators may underestimate organic aerosols, the major component of smog particles. Resultant air pollution from these particles not only affect human health but also create unknown effects on climate change calculations. [University of California-Irvine Today]
• Mixed consequences involving CFC substitutes -- An international team of researchers warn that while the use of hydrofluorocarbons (HFCs) as a substitute for chlorofluorocarbons (CFCs) appear to have been good for the Earth's protective ozone layer in the stratosphere, these HFCs may have an unintended consequence on the planetary climate, as the HFCs appear to be climatically active as potent greenhouse gases and many of these species may be extremely-long lived. They do note that since the CFCs are active greenhouse gases, their elimination should be good for the climate. The researchers recommend that the most potent HFC species should be regulated. [EMPA, Swiss Federal Laboratories for Materials Science and Technology]

CLIMATE AND THE BIOSPHERE

• Arctic sea life persists in winter --Researchers who participated in a recently completed National Science Foundation(NSF) funded research cruise onboard the US Coast Guard icebreaker Healy to the Bering, Chukchi and Beaufort Seas were surprised by the amount of non-dormant marine life including active zooplankton in these frigid and dark waters surrounding the Alaskan coast even in winter. These surprising results may have implications for climate modeling, especially in the Arctic basin where changes in the ecosystem have been occurring in conjunction with changing climate. [National Science Foundation News]
• Increasing temperatures and climate change appear to alter bird migration patterns -- Researchers at the University of North Carolina at Chapel Hill claim that rising temperatures associated with changing climate are responsible to changes in the migratory paths of birds in eastern North America that have been observed over ten years of observations by bird watchers to eBird, a citizen science program database. [University of North Carolina at Chapel Hill News]
• Increased global temperatures may threaten wild cereals -- Researchers at Israel's University of Haifa warn that many of the wild cereals that have been the progenitors of the various staple cereal crops used to feed humans and animals around the world such as wheat and barley have undergone genetic change over the last quarter century. These changes in these wild cereals, many of them negatively affecting these species, appear to have occurred due to increased global temperature. Consequently, these researchers warn that projected increases in temperature could indirectly have a negative impact on food production. [University of Haifa]
• Climate change may have driven evolutionary shrinking in size of early mammals -- Researchers from the University of Nebraska-Lincoln, the Florida Museum of Natural History at the University of Florida and colleagues report that they have found evidence of the cause-and-effect relationship between temperature and body size of many mammalian species. They cite the example of the earliest known horse Sifrhippus sandae that first appeared in North American forests during the Paleocene-Eocene Thermal Maximum (PETM) nearly 56 million years ago decreased to the size of a small house cat as global temperature increased. They based their evidence on analysis of fossils of these early horses in Wyoming. [National Science Foundation News]

CLIMATE FORECASTS

• A "storm of the century" could become more frequent in the future -- Researchers from Princeton University and the Massachusetts Institute of Technology report that because of projected increases in global sea level along with potentially stronger storms, coastal regions such as the New York City metropolitan area that currently experience a disastrous flood once every century could be hit by such flooding every one or two decades. They obtained these findings on the anticipated severity of future flooding from a simulation tool they developed using various global climate models. [News at Princeton University]
• Past history could be used to improve ecological forecasting -- The director of the Center for Climatic Research at the University of Wisconsin-Madison recently addressed the challenges involved in making predictions about the response of ecological communities to changing climate, noting that past history does provide some perspective to possible response. He noted possible emergence of "no-analog" climates, where future combinations of climate factors may not have existed in modern times, but in ancient times, such as those associated with the end of the last Ice Age, beginning some 20,000 years ago. Therefore, geohistorical and recent data must be combined to improve forecasting ability. [University of Wisconsin-Madison News]

CLIMATE AND SOCIETY

• Modest reduction in rainfall may be related to collapse in classic Maya civilization-- Researchers from Mexico's Yucatan Center for Scientific Research and the United Kingdom's University of Southampton report that the breakdown of the Classic Maya civilization between 800 and 950 AD may have been related to modest reductions in annual rainfall ranging from 25 to 40 percent. [University of Southampton]
• 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 -- Bill Huskin, a DataStreme LIT Leader and Atmospheric Educational Resource Associate from Doylestown, PA, reported on the emergence of indicators of an early spring. He noted that spring bulbs were beginning to bloom and other plants were budding, at least four weeks ahead of schedule. The fruit trees in his orchard are beginning to bloom, when normal bloom is in mid-April. Birds are also beginning to build nests and hawks are migrating some three to four weeks early.

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:

• 27 February 1717...What was perhaps the greatest snow in New England history commenced on this date. During a ten-day period, a series of four snowstorms dumped three feet of snow upon Boston, and the city was snowbound for two weeks. Up to six feet of snow was reported farther to the north, and drifts covered many one-story homes. (David Ludlum)
• 27 February 1988...Rapid City, SD established a February record with an afternoon high of 75 degrees. (The National Weather Summary) (Storm Data)
• 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)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2012, The American Meteorological Society.