WEEK THREE: 4-8 February 2013

ITEMS OF INTEREST

• High-quality maps of February temperature and precipitation normals across US available -- The PRISM Climate Group at Oregon State University has prepared high-resolution maps depicting February's normal maximum temperature, minimum temperature and precipitation totals across the 48 coterminous United States for the current 1981-2010 climate normals interval. These maps, with a 800-meter resolution, were produced using the PRISM (Parameter-elevation Regressions on Independent Slopes Model) climate mapping system.
• February weather calendar for a city near you -- The Midwestern Regional Climate Center maintains an interactive website that permits the public to produce a ready to print weather calendar for any given month of the year, such as February, at any of approximately 270 weather stations around the nation. (These stations are NOAA's ThreadEx stations.) The entries for each day of the month includes: Normal maximum temperature, normal minimum temperature, normal daily heating and cooling degree days, normal daily precipitation, record maximum temperature, record minimum temperature, and record daily precipitation; the current normals for 1981-2010.
• Groundhog legend could be affected changing climate -- An article appearing in the "Washington Post" last week before Groundhog Day (2 February 2013) describes how increased temperatures associated with changing climate could affect the response of groundhogs or other marmots to awakening from their torpor (or state of hibernation) in early February. [Washington Post] ( Editor's note: Special thanks is extended to Dr. Bob Weinbeck of the AMS Education Office in Washington, DC for forwarding this article. EJH)
• Small asteroid should safely pass Earth this month -- Astronomers with NASA's Near-Earth Object Program Office report that the small near-Earth asteroid 2012 DA14 should pass within 17,000 miles of Planet Earth on Friday, 15 February 2013/ While this asteroid will make an approach inside the ring of geosynchronous weather and communications satellites surrounding Earth that are approximately 23,000 miles above the equator, the asteroid will have little chance of making a collision with Earth. The 150-foot diameter may be viewed with a small telescope from Indonesia. [NASA JPL]
• Monitoring the seasonal motions of the sun -- If you would like more background information concerning how the sun appears to across your local sky, along with how you can access the times of local sunrise and local sunset, for your hometown on any day throughout year, please read this week's Supplemental Information...In Greater Depth.

CURRENT CLIMATE STATUS

• Unseasonably cold winter unfolds across northeast China and Korea --A map of land surface temperature anomalies (or differences in observed and average temperatures) across China and its northeastern Asian neighbors was produced for the time interval stretching from late November 2012 through early January 2013 from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. This map reveals much below average temperatures for this interval across this region, which corresponds to air temperature readings made at conventional weather stations. A portion of the Yellow River was frozen. [NASA Earth Observatory]

CURRENT CLIMATE MONITORING

• Potent August storm from Siberia did not cause record low Arctic sea ice in 2012 -- Researchers at the University of Washington claim that "The Great Arctic Cyclone of August 2012" did not cause the historic sea ice minimum across the Arctic Ocean basin observed in September. This storm was the most powerful of August storms and the 13th most powerful of any Arctic storm since satellite records began more than three decades ago. Although this potent August storm that originated over Siberia was accompanied by unseasonably strong winds across the entire Arctic basin, increased temperatures remain primarily responsible for the record sea ice minimum. [University of Washington News]
• Viewing aurora in a new light -- Researchers from NASA's Goddard Space Flight Center and a California aerospace company will be launching a sounding rocket from Poker Flat in Alaska in February to study the aurora borealis (or northern lights) that should occur over this polar region. The sounding rocket is part of the VISIONS (VISualizing Ion Outflow via Neutral atom imaging during a Substorm) mission and will carry several specially designed instruments designed to study the stream of oxygen atoms leaving the Earth's atmosphere in the auroral wind during a 15-minute flight. [NASA GSFC News]
• Instrument on Space Station to scan globe for weather and climate data -- NASA will install the RapidScat instrument on the International Space Station (ISS) that is designed to monitor surface winds over large water bodies. This instrument is called a scatterometer and will be used to help scientists monitor the interactions between the atmosphere and oceans, especially for the sea currents that influence environmental conditions across the globe, including the determination of El Niño events. High frequency radar pulses are bounced off the ocean surface to determine the sea state, which can then be used to determine surface wind speeds and direction. This new ISS-RapidSat instrument, which will be sent to ISS in 2014 represents a replacement for the SeaWinds scatterometer aboard NASA's QuikScat satellite that experienced an age-related antenna failure in 2009. [NASA JPL]
• 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

• Cities can affect temperatures many miles away -- A new study conducted by scientists at the Scripps Institution of Oceanography; University of California, San Diego; Florida State University; and the National Center for Atmospheric Research indicates that "waste heat" generated by human activity in large metropolitan areas can influence air temperatures thousands of miles distant. The effect from waste heat is distinct from the "urban heat island" effect. The temperature changes associated with waste heat at some distance from the urban areas would be the result in a change in the character of the jet stream and other major weather systems because of the heat produced in the urban areas. Some distant areas such as across northern sections of North America and Asia were warmed in winter, while areas in Europe were cooled in autumn because of the changes in the jet stream. [NCAR/UCAR AtmosNews]
• Increases in worldwide extreme rainfall events linked to increased global temperatures -- A team of researchers from Australia and Canada report that increases in the intensity of extreme rainfall events around the world can be linked to increases in global temperatures. Basing their conclusions upon extreme rainfall events and atmospheric temperatures from approximately 8000 weather observing stations around the world between 1900 and 2009, they found that a 7 percent increase in extreme rainfall intensity occurred for every Celsius degree increase in global atmospheric temperature. [University of Adelaide News]
• Antarctic ozone depletion affects atmospheric and oceanic circulation patterns -- Using numerical simulations of four wind patterns, researchers at Pennsylvania State University have determined that the depletion of stratospheric ozone over Antarctica represents a more important factor in shifting the Southern Hemisphere jet stream toward the south than increasing levels of greenhouse gases. The southward shift in this jet stream has been determined to create changes in the precipitation and oceanic circulation patterns across the Southern Hemisphere. The researchers believe that the jet stream could shift back toward the north as the depleted region of ozone, often identified as the "ozone hole", would recover. [Penn State Live] In related research, scientists from Johns Hopkins University and colleagues from the US and Australia have found that the reduced stratospheric ozone layer over Antarctic have changed the way in which the waters of the southern oceans mix, which can potentially alter the amount of carbon dioxide in the atmosphere. Changes appear to have occurred in the upwelling of the circumpolar waters of the southern oceans, which appear consistent with the strengthening of surface winds. [Johns Hopkins University HUB]

• Role of Amazon forests on global carbon cycle studied -- Scientists at the US Department of Energy's Lawrence Berkeley National Laboratory and their colleagues in the United States, Brazil, Canada and Germany have devised an analytical method to help detect forest mortality patterns and trends using a combination of fieldwork, satellite images and simulation modeling. These efforts are being used to determine the role that Amazon forests play in the global climate system, primarily in influencing the planetary carbon cycle. [Lawrence Berkley National Laboratory]
• Spring may arrive earlier for North American forests -- A team of researchers from Princeton University claim that deciduous trees across the continental United States could send out new leaves in spring as much as 17 days earlier by 2100 than what they did before global temperatures began rising. They based their claims on a model that used increased temperatures and the waning number of cold days to predict spring bud-burst. With the earlier spring bud-burst dates due to a changing climate, the composition of Northeast forests could change, with a boost given to their ability to sequester atmospheric carbon dioxide. [Princeton University Journal Watch]

PALEOCLIMATE RECONSTRUCTION

• Hypothesis that comet attacks ended Clovis culture refuted -- A scientist at the Sandia National Laboratory and colleagues from 14 academic institutions rebut the speculative hypothesis that comets exploding on the Earth's surface changed the large-scale climate sufficiently to end the prehistoric Clovis culture across North America approximately 13,000 years ago. These researchers found no large impact craters from this time that would have been sufficient to cause climate change and note that other explanations for the disappearance of this culture need to be found. [Sandia Labs News Releases]

CLIMATE FORECASTS

• Establishing a "calendar" of seasonal drought patterns based on historical probability -- Researchers at Oklahoma State University are developing a reliable "calendar" of seasonal drought patterns using soil water deficits that could help farmers optimize crop production by avoiding days prone to drought using historical probability. This method uses soil moisture properties to determine crop water stress rather than methods that typically use rainfall and temperature data. [American Society of Agronomy News Releases]

CLIMATE AND SOCIETY

• Interagency report on threat of climate change to health, safety and economy along nation's coasts -- Officials with NOAA's Office of Ocean and Coastal Resource Management and the US Geological Survey (USGS) recently released a technical report entitled "Coastal Impacts, Adaptation, and Vulnerabilities: A Technical Input to the 2013 National Climate Assessment." This report, which was prepared by leading scientists and experts, warns that the effects of climate change will continue to threaten the health and vitality of the social, economic and natural systems of US coastal communities. Furthermore, the need for increased coordination and planning to ensure the resiliency of these coastal communities is stressed. [NOAA News] or [USGS Newsroom]
• 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.

Climate sensitivity is a relatively new and powerful concept in climate science. It is a measure of how responsive the temperature of Earth's climate system is to a change in radiative forcing due to increases in atmospheric carbon dioxide, an important greenhouse gas, combined with the contributions of feedbacks within the system. Specifically, the term is defined as how much the global mean surface temperature will increase if there is a doubling of atmospheric greenhouse gases (in terms of equivalent CO₂), once the planet has had a chance to settle into a new equilibrium after the increase occurs. In other words, it is an assessment of how Earth's climate will respond to that doubling.

According to NASA climate scientist James Hansen, the concept of climate sensitivity has its origins in a request made by President Jimmy Carter in 1979 for the National Academy of Sciences (NAS) to report on the potential impact on climate of the increasing atmospheric concentration of carbon dioxide. Jule G. Charney (1917-1981) of the Massachusetts Institute of Technology (MIT) led the Academy investigation team. He designed a now classic experiment where computer models of Earth's climate system had the atmospheric concentration of CO₂ doubled while all other variables (except temperature) were held constant.

The addition of CO₂ makes the atmosphere more opaque for outgoing infrared radiation (heat), warming the lower atmosphere and cooling the upper atmosphere. Applying basic radiation laws, Charney found that doubling the atmospheric CO₂ concentration would reduce the net radiative flux (from Earth to space) at the tropopause by a global average of about 4 watts per square meter (W/m²). How much warmer would Earth's surface become as a consequence of this enhanced greenhouse effect? According to the Stefan-Boltzmann law, the radiation emitted by an object is directly proportional to the fourth power of the object's absolute temperature. To reestablish radiative equilibrium following a doubling of atmospheric CO₂, Earth must radiate to space an additional 4 W/m², brought about by a global warming of 1.2 Celsius degrees (or 0.3 Celsius degrees per W/m²).

Charney's initial experiment accounted for the effect of a forcing agent (i.e., atmospheric CO₂) on global climate but not the influence of feedbacks. As noted in the Concept of the Week for Week 2, forcing agents and mechanisms drive climate change, while feedbacks determine the magnitude of climate change. Hence, Charney's "no-feedback" experiment significantly underestimates the amount of global warming likely to accompany a doubling of atmospheric CO₂. With inclusion of feedbacks, the 1979 Academy study indicated that global warming could range from 2 to 3.5 Celsius degrees. The most recent IPCC report (AR4) estimates the magnitude of warming with feedbacks incorporated as 3 Celsius degrees with a range of uncertainty of 2 to 4.5 Celsius degrees. This greater sensitivity depends primarily on all the different feedbacks, both positive and negative, that either amplify or diminish the greenhouse effect. The three primary feedbacks involve clouds, sea ice, and water vapor.

In summary, climate sensitivity is usually expressed in terms of the equilibrium change in global mean annual surface temperature caused by an increment in downward infrared radiative flux that would result from sustained doubling of atmospheric CO₂ concentration compared to its pre-industrial level (taken to be 280 ppmv).

Concept of the Week: Questions

1. All other factors being equal, the addition of CO₂ to the atmosphere [(increases) (decreases)(has no effect upon)] the flux of infrared radiation from Earth's surface to space.
2. Charney's initial estimate of the amount of global warming that would accompany a doubling of atmospheric CO₂ [(did)(did not)] account for the temperature change(s) likely to accompany feedbacks in Earth's climate system.

Historical Events:

• 4 February 1996...Frigid temperatures continued over the northern US and spread southward to the Gulf Coast. A cooperative observer near Couderay, WI reported a temperature of 55 degrees below zero, which set a new record low for the Badger State. This reading is also the lowest temperature ever recorded east of the Mississippi River. Amasa, MI checked in with 51 degrees below zero, which tied the record low for Michigan. Tulsa, OK had a morning low of 11 degrees below zero for its lowest temperature in 66 years. Muskegon, MI recorded an all-time low of 19 degrees below zero. La Crosse, WI completed it longest stretch of subzero temperatures ever (144 hours). The center of the frigid arctic high-pressure system moved over Louisiana, setting an all-time record high barometric pressure of 30.82 inches (1043.6 millibars) at Baton Rouge. (Intellicast)
• 5 February 1887...San Francisco, CA experienced its greatest snowstorm of record. Nearly four (3.7) inches were reported in downtown San Francisco, and the western hills of the city received seven inches. Excited crowds went on a snowball-throwing rampage. (David Ludlum)
• 5 February 1996...The "great arctic outbreak of '96" began to wind down, but not before one more frigid morning. Greene, RI reported a state record low temperature of 25 degrees below zero. (Intellicast)
• 6 February 1933...The temperature at Oimekon, Russia fell to 90 degrees (Fahrenheit), tying the previous lowest recorded temperature in Asia set in 1892. (The Weather Doctor)
• 6 February 1933...The highest reliably observed ocean wave was seen by crew of the US Navy oiler, USS Ramapo, in the North Pacific during the night on its way from Manila to San Diego. The wave was estimated (by triangulation) to have a height of 112 feet. Average winds at the time were 78 mph. (Accord's Weather Guide Calendar)
• 6 February 1978...A massive nor'easter buried the cities of the northeastern U.S. The Boston, MA area received 25 to 30 inches in "The Great New England Blizzard of '78" By the time the storm ended late on the 7th, Boston had 27.1 inches of new snow to set an all-time single storm snowfall record. (David Ludlum) (Intellicast)
• 7 February 1892...The lowest temperature ever recorded to that time in Asia was reported from Verkhoyansk, Russia with a 90-degree below zero reading. This record was subsequently tied in 1933. (The Weather Doctor)
• 7 February 1989...The low of 43 degrees below zero at Boca, CA was a state record for the month of February. In Utah, lows of -32 degrees at Bryce Canyon, -27 degrees at Delta, -29 degrees at Dugway, and -38 degrees at Vernal were all-time records for those locations. (The National Weather Summary)
• 8 February 1933...The record low temperature for the state of Texas was set at Seminole when the mercury dropped to 23 degrees below zero. (Intellicast)
• 8 February 1936...The temperature at Denver, CO plunged to its all-time record low temperature of 30 degrees below zero. (David Ludlum) (The Weather Channel)
• 9 February 1899...Norway House, Manitoba reported a temperature of 63 degrees below zero to set the province's record for lowest temperature. (The Weather Doctor)
• 9 February 1933...The temperature at Moran, WY, located next to Teton National Park, plunged to 63 degrees below zero to establish a state record. The temperature at the Riverside Ranger Station in Montana near West Yellowstone, MT dipped to 66 below zero to establish a record for the state, and a record for the nation, which stood until 1954. (David Ludlum)
• 9 February 1934...The mercury dipped to 51 degrees below zero at Vanderbilt to establish a record for the state of Michigan. The temperature at Stillwater Reservoir plunged to 52 degrees below zero to establish a record for the state of New York; this record was subsequently tied in February 1979. (David Ludlum) (NCDC)
• 10 February 1899...The record low temperature for the state of Ohio was set at Milligan when the mercury dipped to 39 degrees below zero. The record low temperature for Virginia was also set at Monterey with 29 degrees below zero; this record has been broken in January 1985. (Intellicast) (Sandra and TI Richard Sanders - 1987)
• 10 February 1933...The temperature at Seneca, OR fell to 54 degrees below zero, tying Oregon's statewide low temperature record set the previous day at Ukiah. (NCDC)
• 10 February 2011...The Oklahoma Mesonet weather station at Nowata recorded a temperature of 31 degrees below zero, which is the lowest reading in the Sooner State, breaking the previous statewide record low of 27 degrees below zero set at several stations in earlier years. By midafternoon, the temperature at Nowata increased by 53 Fahrenheit degrees to 22 degrees above zero. (Accord Weather Guide Calendar) (NCDC)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2013, The American Meteorological Society.