WEEKLY CLIMATE NEWS

WEEKLY CLIMATE NEWS

25 February-1 March 2013

ITEMS OF INTEREST

A change in meteorological seasons -- Thursday, 28 February 2013, 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 2013) 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 -- This year (2013) is considered a "normal" year with 365 days, while last year was a "leap" year with 366 days. 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.
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.
Becoming AWARE -- Commencing next Sunday (3 March 2013), NOAA's National Weather Service and its partner, the Federal Emergency Management Agency (FEMA) will be observing "National Severe Weather Preparedness Week" that will run through the following Saturday (9 March). The theme for this year's National Severe Weather Preparedness Week is "Be a Force of Nature." The NOAA "Weather-Ready Nation" website (http://www.nws.noaa.gov/com/weatherreadynation/force.html), contains links that allow the public to "Be a Force of Nature" in their communities through Tweet, a blog post, or a presentation. Other stations throughout the nation have either conducted or will conduct their Severe Weather Awareness Weeks in the next several months as the spring season for severe thunderstorms unfolds.

CURRENT CLIMATE STATUS

Review of global weather and climate for January 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 January 2013 was 54.57 degrees Fahrenheit (or 12.54 degrees Celsius), which tied January 1995 for the ninth highest global temperature for any January since global climate records began in 1880. The average global ocean surface temperature for January was the eighth highest on record, while the global land surface temperature for January 2013 was thirteenth highest. The scientists also noted that January 2013 was also the 335th consecutive month with a combined global temperature that exceeded the 20th century average (1901-2000). They also noted that neither El Niño or La Niña conditions were found across the equatorial Pacific Ocean, which resulted in slightly below average sea surface temperatures across the equatorial surface waters of the eastern half of the Pacific.
The extent of the Northern Hemisphere snow cover during January 2013 was the sixth highest for the period of record that started in 1967, while January Arctic sea ice extent was the sixth smallest monthly extent since satellite surveillance began in 1979. On the other hand, Antarctic sea ice extent was the seventh largest January sea ice extent on record. [NOAA/NCDC State of the Climate/NCDC]
January national drought report -- The National Climate Data Center has posted its January 2013 drought report online. Using the Palmer Drought Severity Index, approximately 32 percent of the coterminous United States experienced severe to extreme drought conditions at the end of January, while two percent of the area had severely to extremely wet conditions.

CURRENT CLIMATE MONITORING

New national maps of long-term average evapotranspiration rates produced -- Hydrologists with the US Geological Survey (USGS) have produced a new map of the 30-year average of annual average evapotranspiration rates across the 48 coterminous United States between 1971-2000. They based their analysis of evapotranspiration (the amount of water evaporated from the soil and the water lost from plants via transpiration) up temperature and precipitation data collected over the 30 years from NOAA, streamflow data and from the land use data obtained from NASA Landsat satellites. The new map should be useful not only for water managers, but also for climatologists. [USGS Newsroom]
Datasets of numerous atmospheric species collected by HIPPO study made available -- Two websites have been created that make data collected during the HIAPER Pole-to-Pole Observations (HIPPO) study of greenhouse gases and aerosols available to the research community and to the public. The datasets include high-resolution measurements of over 90 unique atmospheric species at various levels in the atmosphere collected during a series of nearly pole-to-pole flights over the Pacific Ocean during each seasons of the year. These data would be of use in global climate models due to the consideration of the carbon cycle. [Harvard University Gazette]
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

Contrails could increase high level clouds and temperatures -- A team of researchers at Penn State University report that their analysis of NOAA satellite images and weather data collected from across the eastern United States indicated an increase in the occurrence of high-level clouds due to contrails (condensation trails) produced by jet aircraft over the last 35 to 50 years. They also claim that although the persistent high-level clouds produced by the contrails could reflect incident solar radiation, they could do more effective at trapping upwelling thermal radiation, thereby heating the atmosphere under the clouds. [Penn State News]
Utah's lake-effect snow gets help from mountains -- Running computer simulations, researchers at the University of Utah have found that the lake-effect snow generated by cold air moving across Utah's Great Salt Lake can be triggered by the presence of the higher topography of the Wasatch Mountains to the east of Salt Lake City. These mountains provide orographic lift that enhances the lake-effect snow even over the Lake, creating what would be known as the "Great Salt Lake powder skiing machine," which helps drive the winter sports economy for Utah. The researchers also studied how the mountains located in Idaho and Nevada to the north and northwest of Great Salt Lake can affect the lake-effect snow across the Salt Lake City metropolitan area and the Wasatch Range. [University of Utah News Center]
Rate of cloud droplet formation not affected by pollution -- Researchers at the Georgia Institute of Technology who were studying the wide range of airborne particles including those that were hydrocarbon-rich particles produced by the 2010 Deepwater Horizon oil spill in the Gulf of Mexico report that oily, organic coatings on particles do not appear to significantly affect the rate at which cloud droplets form. The researchers claim that their findings may help reduce the uncertainty of climate model predictions, as scientists had thought that organic and viscous oily coatings on aerosols produced by combusted biomass and petroleum would slow the condensation rate during the formation of cloud droplets. [Georgia Tech]

CLIMATE FORECASTS

New three-month Seasonal Climate Outlooks released for spring -- Forecasters at NOAA's Climate Prediction Center (CPC) released their Seasonal Climate Outlooks last week for meteorological spring (the three-months running from March through May 2013) across the nation. According to their temperature outlook, Their outlook indicates a high chance of above average spring temperatures across a large section of the 48 coterminous United States, with the greatest probability of such an occurrence across the South Central States from west Texas eastward to Georgia. Most areas of the country to the east of the Mississippi River should also experience a better than even chance of above average spring temperatures. Only the Northwest appear would appear to have a good chance for below average temperatures. Elsewhere, near equal chances of warmer or cooler than normal conditions were foreseen.
Their precipitation outlook calls for better than even chances of dry spring conditions for a large section of the West Coast and the Southwest, especially across central and northern California. Probabilities for dry weather were also better than average across sections of the Southeast, especially across Florida during the next three months. On the other hand, sections of the Midwest around the Great Lakes were expected to have a wetter than average spring. The rest of the coterminous states should have equal chances of below and above average spring precipitation. [NOAA Climate Prediction Center] Outlooks for March are also available. A summary of the prognostic discussion of the outlook for non-technical users is available from CPC. These forecasts were based in part that the current ENSO-neutral conditions (ENSO = El Niño/Southern Oscillation) should continue into spring, where neither El Niño nor La Niña conditions should prevail.
Polar regions could receive more snow, while midlatitudes would receive less in future -- Using a new climate model developed at NOAA's Geophysical Fluid Dynamics Laboratory (GFDL), scientists at GFDL and Princeton University predict that snowfall would increase across polar regions and the highest mountain elevations, but would decrease across midlatitudes, including the United States, over the next 70 years. The overall decrease in snowfall worldwide would be due to increased global temperatures as a result of increased atmospheric carbon dioxide levels. In the United States, a lack of adequate snow would create problems as snowmelt is a major source of usable fresh water. [Princeton University Journal Watch]

CLIMATE AND SOCIETY

Assessing the impacts of climate change on agriculture -- The US Department of Agriculture (USDA) recently released a comprehensive National Climate Assessment report entitled Climate Change and Agriculture in the United States: Effects and Adaptation that explores the current effects of changing climate on the nation's agriculture as well as projections of change that may occur over the next 100 years. This current assessment, which was produced by researchers from the USDA, the National Center for Atmospheric Research (NCAR), the university community and other nongovernmental organizations, represents the second such assessment following the first that was produced in 2008. [UCAR/NCAR AtmosNews]
New forecasting efforts could help solar energy industry -- A research team at the National Center for Atmospheric Research (NCAR) is designing a prototype system that would be used to forecast the amount of incident solar radiation at 15-minute intervals arriving over specific solar energy power facilities with a lead time of up to 36-hours. These forecasts would be used by facility managers to anticipated the amount of available solar energy at their facilities on a nearly continuous basis. The focus on the forecasting efforts has been involved with producing detailed predictions of clouds and atmospheric particles that can reduce incoming solar energy.[UCAR/NCAR AtmosNews]
Earthquake catastrophes and fatalities predicted to rise during 21st century -- Engineering geologists with the US Geological Survey (USGS) warn that as the world's population is projected to increase during the 21st century, the number of fatalities due to earthquakes and associated tsunamis would increase. They found that the number of catastrophic earthquakes that have claimed at least 50,000 lives each has increased from 1500 AD to the present, along with the increased global population. Using new 21st-century population projections by the United Nations they projected that approximately 21 catastrophic earthquakes would occur in the 21st century, triple the number in the 20th century and that the total deaths in the century could more than double to approximately 3.5 million people. Four catastrophic earthquakes have already occurred since so far this century, including the 2004 Sumatra-Andaman earthquake (and tsunami) and 2010 Haiti earthquake that each may have killed over 200,000 people. [USGS Newsroom]
Geoengineering coalitions raise geopolitical questions -- Researchers at the Carnegie Institution for Science recently reported on new modeling work they conducted to determine the impact of solar geoengineering would have in attempting to reduce those effects upon climate change due to increased greenhouse gas emissions by deflecting some solar radiation reaching Earth. They found that powerful coalitions between a few major nations could have the incentive to exclude other countries from participating in the geoengineering decision-making process. [Carnegie Institution for Science]
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.

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.)

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.
In the Southern Hemisphere, the jet stream winds to be directed generally toward the [(south), (east), (west)].

Historical Events:

25 February 1914...South Carolina had its biggest snowstorm in modern history, as 18 inches fell at Society Hill. (Intellicast)
25 February 1922...The temperature at Los Angeles, CA soared to 92 degrees to establish a record for the month of February. (David Ludlum)
26 February 1969...Both Portsmouth, NH and Portland, ME set new single storm snowfall records with 33.8 inches and 26.9 inches, respectively. (Intellicast)
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)

Return to DataStreme ECS website