WEEK THREE: 10-14 February 2014

ITEMS OF INTEREST

• Winter Olympics weather and climatology -- The 2014 Winter Olympics ( officially the XXII Olympic Winter Games) are currently underway in the Russian city of Sochi. While indoor sports are in Sochi, alpine Olympic events will be located at the Rosa Khutar ski resort near Krasnaya Polyana, a resort town in the Western Caucasus Mountains near Sochi.
  An image obtained from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft shows the terrain around the Sochi Winter Olympic Games Coastal Cluster, the site for arena sports and the opening and closing ceremonies. [NASA Earth Science News Team] Another image generated from data collected by the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument on NASA's Aqua Satellite at the start of last week shows a larger view of the area around Sochi and the snow on the nearby Caucasus Mountains. [NASA Earth Observatory]
  The Games will continue through Sunday 23 February.
  Monthly average temperature and precipitation data for Sochi, Russia are available.
• Planet Earth seen as an "evening star" by Mars Rover -- An image of Planet Earth and its satellite, the Moon, was made from the surface of Planet Mars just after sunset by an instrument on the NASA Mars Rover Curiosity at the end of last month. The Earth and Moon appear on this image as specks because the distance between Mars and Earth was approximately 99 million miles. [NASA Jet Propulsion Laboratory]
• Free admission into the National Parks and Forests-- This upcoming weekend, Saturday, 15 February through Monday 17 February 2014, has been designated by the National Park Service as a fee-free weekend in honor of Presidents Day. This fee waiver will cover entrance and commercial tour fees in many of the national parks and monuments administered by the Park Service. [National Park Service Fee Free Days]
• 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 MONITORING

• New 24-hour rainfall record recognized in Colorado -- The Colorado Climate Extremes Committee recently approved that the rainfall event that occurred last September in Colorado be accepted as the new state 24-hour precipitation record for the Centennial State. This new record, which needs final approval by the National Climatic Data Center, is for the 11.85 inches of rain that fell from midnight to midnight on 12 September 2013 and was recorded by a rain gauge at the Rod and Gun Meteorological Station at Fort Carson. [Colorado State University News]
• Past and future climate of Greenland investigated -- Physical oceanographers from Woods Hole Oceanographic Institution and the Massachusetts Institute of Technology recently produced a review paper that describes what scientists have learned from their research on and around Greenland over the past two decades in attempting to assess changes in the climate of Greenland. During this time span, the rate of ice loss from Greenland's Ice Sheet had increased four-fold and has served as a significant contributor to global sea level rise. An explanation is made of the mechanisms that cause the melting of the ice sheet especially along its margin along the ocean. The paper also describes the measurements and technology that was used. [Woods Hole Oceanographic Institution News Release]
• Evolution and structure of moisture-laden atmospheric rivers studied -- During the past week scientists from NOAA's Earth System Research Laboratory and Scripps Institute for Oceanography have been flying onboard the NOAA Gulfstream IV aircraft and taking measurements of atmospheric temperature, humidity, pressure and wind speed/direction over the North Pacific Ocean off the California coast. They are collecting these data to better understand the evolution and structure of "atmospheric rivers" or narrow corridors of humid air that travel for thousands of miles across the North Pacific and bring abundant quantities of water vapor to the US West Coast that can replenish water supplies, build snowpack on the western mountain ranges and even cause flooding rain events. [NOAA Office of Oceanic & Atmospheric Research 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]

CLIMATE FORCING

• Drought in Amazon Basin adds carbon dioxide to atmosphere -- A team of scientists from the United States, the United Kingdom and Brazil who conducted a field experiment in the Amazon Basin of South America have found that recent drought conditions across the Basin caused by reduced annual rainfall totals have resulted in an increased release in carbon dioxide into the atmosphere, as the quantity of this greenhouse gas absorbed by the lush tropical vegetation has decreased. [NOAA Office of Oceanic & Atmospheric Research News]

PALEOCLIMATE RECONSTRUCTION

• Wildfires and forest emissions may have contributed to hot ancient Earth -- A researcher at Yale University and her colleagues using the NASA Goddard Institute for Space Studies Model-E2 global Earth system model claim that the release of volatile organic compounds from Earth's forests together with the smoke from wildfires approximately 3 million years ago appear to have had a far greater impact on global warming at that time than ancient levels of atmospheric carbon dioxide. They calculated that concentrations of tropospheric ozone, aerosol particles, and methane during the mid-Pliocene epoch were twice the levels observed in the pre-industrial era, since more of Earth was covered in forest. [Yale News]

CLIMATE AND SOCIETY

• 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. A recent IPCC report (AR4) estimated 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:

• 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)
• 11 February 1895...Braemar (Grampian), Scotland reported a temperature of 17 degrees below zero, the lowest temperature ever measured in the United Kingdom. (The Weather Doctor)
• 11 February 1899...Perhaps the greatest of all arctic outbreaks commenced on this date. The record low temperature for Washington, DC was set when the temperature fell to 15 degrees below zero. (David Ludlum) (Intellicast)
• 11 February 1935...Temperature of 11 degrees below zero at Ifrane, Morocco was the lowest temperature ever in Africa. (The Weather Doctor)
• 11 February 1970...Mount Washington, NH, the highest point in New England, recorded 10.38 inches during a 24-hour span (10^th-11^th) to set a statewide 24 hour maximum precipitation record. (NCDC)
• 11 February 1999...Tahtsa Lake, located in the Whitesail Range of the Coast Mountains of British Columbia reported 57 inches of snow, which set a new 24-hour snowfall record for Canada, eclipsing the old record of 46.5 inches of snow that fell at Lakelse, BC on 17 January 1974. This former record replaced a 44.0 inch summertime snowfall on 29 June 1963 at Livingston Ranger Station, AB. (Accord's Weather Guide Calendar) (The Weather Doctor)
• 12 February 1899...Texas and the eastern Great Plains experienced their coldest morning of modern record. The temperature at Camp Clarke, NE plunged to 47 degrees below zero to establish a record for the Cornhusker State; this record has been tied in December 1989. (David Ludlum)
• 13 February 1784...Ice floes blocked the Mississippi River at New Orleans, then passed into the Gulf of Mexico. The only other time this occurred was during the "Great Arctic Outbreak" of 1899. (David Ludlum)
• 13 February 1899...It was the coldest morning of record along the Gulf Coast. The mercury dipped to 2 degrees below zero at Tallahassee, the lowest reading of record for the state of Florida. The record low temperature for the state of Louisiana was set at Minden, when the thermometer fell to 16 degrees below zero. A trace of snow fell at Fort Myers, FL. This was the farthest south snow has ever been observed in the U.S. until 1977 when snow fell in Miami. The lowest temperature ever recorded at Dayton, OH occurred when it dropped to 28 degrees below zero. (David Ludlum) (Intellicast)
• 13 February 1905...Morning lows of 29 degrees below zero at Pond, AR, 40 degrees below at Lebanon, KS, and 40 below at Warsaw, MO established all-time records for those three states. (The Weather Channel)
• 15 February 1936...The temperature at Parshall, ND plunged to 60 degrees below zero to establish a state record low temperature. On the 6^th of July that same year, the temperature at Steele, ND hit 121 degrees, also a state record high temperature. (David Ludlum)
• 16 February 1903...The temperature at Pokegama Dam, MN plunged to 59 degrees below zero to establish a state record. (David Ludlum) This record has since been broken with a 60 degree below reading in 1996. (NCDC)
• 16 February 1929...Britain's greatest snowfall of 70.9 inches fell in just 15 hours at Dartmoor, Great Britain. (The Weather Doctor)
• 16 February 1943...Record cold prevailed in the northeastern U.S. The morning low of 32 degrees below zero at Falls Village, CT established a state record, yet the afternoon high that day was 20 degrees above zero. In January 1961, this Connecticut record low was tied. (David Ludlum) (The Weather Channel)
• 16 February 1966...Heavy rain fell in Whenuapai, New Zealand, with 4.2 inches of rain falling in one hour, a new record for that time in New Zealand. (The Weather Doctor)
• 16 February 1989...A surge of arctic air produced all-time record high barometric pressure readings of 31.08 inches at Duluth, MN, 30.97 inches at Chicago, IL and 30.94 inches at South Bend, IN. Readings of 31.00 inches at Milwaukee, WI and 30.98 inches at Rockford, IL tied their all-time records. (The National Weather Summary)
• 16 February 1996...A coastal storm produced heavy snow along the East Coast to push seasonal snowfall totals to new records at several locations. The following cities set new all-time seasonal snowfall records: Lynchburg, VA (8.1 inches new, 51.3 inches seasonal total); Washington/Dulles, VA (7.5, 53.4) ; Washington/National, DC (6.8, 40.8); Baltimore, MD (9.8, 54.9); Philadelphia, PA (7.5, 55.9); Hartford/Bradley, CT (10.3, 90.2) and Providence, RI (7.0, 78.0). (Intellicast)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2014, The American Meteorological Society.