DataStreme ECS WEEK THREE: 20-24 September 2010

ITEMS OF INTEREST

• The Autumnal Equinox -- The Autumnal Equinox will occur late this Wednesday evening (officially at 0309Z, 23 September 2010 or 11:09 PM EDT or 10:09 PM CDT, etc. on 22 September). At that time the noontime sun will appear directly above the equator, representing one of the two times during the year for such an occurrence, with the other being at the vernal equinox in March. The term "equinox" arises from the fact that this time of year represents "equal night" and equal day essentially everywhere. Within the subsequent several days, the length of daylight will become noticeably shorter. This decrease in daylight will continue for another three months to the winter solstice during the early evening of Tuesday, 21 December 2010.
  Editor's note: John White, a meteorologist from North Carolina involved with the AMS Education program, reported that the geosynchronous (or geostationary) satellites make an "satellite eclipse" of the sun near the spring and autumnal equinoxes because of their equatorial orbit, such that these satellites pass through the earth's shadow and the satellite is powered down when the solar array does not receive sufficient sunlight. [For more information, consult NWS Southern Region GOES Satellite FAQ] EJH.
• Harvest Moon --
A full moon that will occur on this coming Thursday is known as "Harvest Moon" since it is the full moon nearest the autumnal equinox. The name Harvest Moon originates from a legend that arises the moonlight from the nearly full moon provides mid-latitude farmers with extra natural light for harvesting their crops before the first frost that ends the growing season. Several astronomical factors involving the earth-moon-sun viewing geometry contribute to making this spectacular late summer (or early fall) event special - a large lunar disk that appears as a pumpkin hanging above the eastern horizon just after sunset for several consecutive evenings.
• NOAA's response to National Academy of Public Administration’s study on national climate service --
Early last week, NOAA Administrator Dr. Jane Lubchenco issued a public statement concerning the final report of the National Academy of Public Administration study on NOAA Climate Service that was requested last year by Congress. [NOAA News]
• Contracts awarded to manage climate data records --
Last week, NOAA officials announced that they have awarded a contract to Global Science & Technology, Inc., of Greenbelt, MD to help manage NOAA's satellite Climate Data Records that are based at the agency's National Climatic Data Center in Asheville, NC. [NOAA News]
• Six new NOAA regional climate service directors named --
Early last week, Department of Commerce Secretary Locke announced the names of the six new NOAA regional climate service directors who will work to provide deliver and provide access to climate products and services as well as to strengthen the regional partnerships between NOAA and the stakeholders in the six regions around the nation that focus on climate. [NOAA News]
• NOAA scientist awarded Service to America Medal --
Dr. Susan Solomon, a senior scientist at NOAA's Earth System Research Laboratory in Boulder, CO, was awarded the Career Achievement Service to America medal in a ceremony last week for her pioneering work in atmospheric research, including identification of the cause for the marked reduction in stratospheric ozone in Antarctica, commonly called the "ozone hole" and her work co-chairing the Working Group 1 of the Intergovernmental Panel on Climate Change that published "The Physical Science Basis" in 2007. [NOAA News]

CURRENT CLIMATE STATUS

• Monitoring this summer's Arctic sea ice extent -- Images obtained from the MODIS and the AMSR-E (Advanced Microwave Scanning Radiometer for EOS) sensors on NASA’s Aqua satellite during the last several weeks show shrinkage of the Arctic sea ice to the seasonal minimum in early September. [NASA Earth Observatory] Researchers at the University of Colorado at Boulder's National Snow and Ice Data Center report that as of mid September, the extent of Arctic sea ice appears to have reached a minimum for the 2010 summer season, with an areal extent that supplants 2009 as the third smallest since routine satellite surveillance commenced in 1979. [University of Colorado] [National Snow and Ice Data Center]
• This year could be close to warmest in more than a century --
Basing their analysis on preliminary data, scientists at NOAA's National Climatic Data Center recently reported that the first eight months of 2010 tied the same period in 1998 for the highest combined land and ocean surface temperature on record worldwide since widespread reliable climate data became available in 1880. They also stated that the global land-ocean combined temperature for the boreal summer/austral winter (the three months of June, July and August) was the second highest on record. Furthermore, the global average land surface temperature for August 2010 was the second highest on record for August, while the global ocean surface temperature tied with 1997 as the sixth highest for August. In addition, they noted that the Arctic sea ice continued its 14-year decline. [NOAA News]
• August drought report --
The National Climate Data Center has posted its August 2010 drought report online. Using the Palmer Drought Severity Index, approximately four percent of the coterminous United States experienced severe to extreme drought conditions at the end of August, while 21 percent of the area had severely to extremely wet conditions.

CURRENT CLIMATE MONITORING

• Mapping this year's Antarctic "ozone hole" -- NASA recently released an image showing the stratospheric ozone concentrations across polar and subpolar latitudes of the Southern Hemisphere from data collected early last week from the Ozone Monitoring Instrument (OMI) onboard the agency’s Aura satellite. At this time of year (early austral spring), the region of relatively low stratospheric ozone concentration levels over Antarctica known as the "ozone hole" has expanded. This season, the areal size of this hole is slightly lower than the long-term (1979-2009) average size. [NASA]
• European marine observation network proposed --
In a recent meeting of the European Science Foundation's Marine Board, more than 100 marine scientists, policy makers and members of industry called for an integrated network of long-term marine observing stations that would monitor the waters surrounding Europe so as to better understand ocean, earth and climate system processes. [EurekAlert!]
• 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

• Monitoring August's worldwide air quality and drought -- Scientists at NASA's Goddard Space Flight Center recently released an image of the August 2010 average global distribution of aerosols produced from data collected by the MODIS sensor on NASA's Terra satellite and displayed in terms of an index called the "aerosol optical depth." This image can be compared with a corresponding image of aerosol optical depth taken by the same instrument in August 2009. Generally speaking, the largest concentrations of aerosols appeared to correspond with the regions of the globe experiencing drought conditions. [NASA Earth Observatory]
• Rainfall in tropical rainforest controlled by aerosols --
An international team of environmental engineers funded by the National Science Foundation have found that aerosols, small airborne particles, that naturally formed in tropical rainforests in Brazil's Amazonian Basin near Manaus appear to help form clouds and control the precipitation in these rainforests. [NSF News]
• Mountains appear to get boost from glaciers --
A research team from the University of Arizona, Yale University, the University of Illinois at Urbana-Champaign; and the Universidad de Chile in Santiago claim that their research in the Patagonian Andes of South America indicates that glaciers could cause mountains in cold climates to grow higher because the glaciers appear to protect the peaks from erosion. [EurekAlert!]
• Monetary grant to study Great Lakes water quality --
The National Science Foundation has recently provided a $5 million grant to a team of 27 researchers from research institutions, including the University of Michigan, to study how extreme weather events caused by climate change affect the water quality of the Laurentide Great Lakes. [University of Michigan]

CLIMATE AND THE BIOSPHERE

• Coral disease outbreaks linked to warm seawater -- Using sea surface temperature data collected from satellites, scientists from NOAA, the Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University and the Australian Institute of Marine Science have found that a strong relationship exists between warm sea water in summer with outbreaks of coral diseases on Australia's Barrier Reef and in addition, relatively mild seawater during the preceding winter season can be linked also to the disease outbreaks. Their research has also contributed to a new experimental Coral Disease Outbreak Risk Map product that is available online. [NOAA News]

CLIMATE MODELING

• Using optimization techniques to estimate climate change reduction --Scientists at the Carnegie Institution's Department of Global Ecology have used the results from five simulation experiments they ran on a global climate model in an optimization model to determine at what latitude where stratospheric aerosols should be intentionally injected to exert the greatest impact in reducing the current trend of increasing global temperatures associated with climate change. [Carnegie Institution for Science]

CLIMATE FORECASTS

• Three-month outlook released -- Last week, forecasters with NOAA's Climate Prediction Center released their three-month temperature and precipitation outlooks for the nation, running from October through December 2010. Their temperature probability outlook indicates that the center of the nation, extending from the southern Plains and southern Rockies northeastward to the Great Lakes should expect a better to much better than even chance of above average temperatures. For those along the Pacific Coast, chances are better than even that below average temperatures could occur. Elsewhere across the coterminous United States, equal chances of below and above average temperatures should be anticipated for the rest of the year. The precipitation probability outlook suggests that the southern tier of states, extending from the Southwest to the Gulf Coast and southeastern Atlantic Coast could experience more than even chances of below average rainfall. On the other hand, the Pacific Northwest should stand a good chance of receiving above average precipitation. Elsewhere, equal chances of below and above average precipitation are forecast. This outlook is based in part on what is seen as a La Niña episode in the equatorial Pacific Ocean. [Climate Prediction Center]
  The Climate Prediction Center also released its US Seasonal Drought Outlook that will run for the rest of the 2010 calendar year. This outlook indicates improvement in the drought conditions across the northern tier of states, especially in the northern Great Lakes and New England, along with some marginal improvement in scattered areas across the Gulf Coast, the Ohio Valley and the Atlantic Seaboard. Drought conditions were anticipated to persist or develop across the Great Basin, the lower Mississippi and Ohio Valleys and the Southeast.
• Current Atlantic hurricane season meets expectations --
Hurricane experts have noted that the 2010 hurricane season at the statistical midpoint of the North Atlantic hurricane season has been extremely active as had been foreseen by several hurricane forecast groups. As of late last week, eleven named tropical cyclones had formed across the basin, which includes the Caribbean Sea and the Gulf of Mexico, including six hurricanes. Earlier this summer, Bill Gray and Phil Klotzbach of Colorado State University had predicted 15 named cyclones and eight hurricanes, while NOAA forecasters anticipated 14 to 23 named cyclones and eight to 14 hurricanes. On a long-term average, 10 named tropical cyclones and six hurricanes can be expected across the basin. [USA Today]

CLIMATE AND SOCIETY

• Guide for protecting public health during drought conditions is released -- The Centers for Disease Control and Prevention (CDC) recently released a document titled "When Every Drop Counts: Protecting Public Health During Drought Conditions – A Guide for Public Health Professionals" that is designed to assist public health officials, practitioners, and others to understand and prepare for drought in their communities. [Centers for Disease Control and Prevention]
• An international perspective on avoiding ill effects of climate change --
At an international workshop on the UK AVOID program held in Washington, DC last week, climate scientists from the United States and the United Kingdom emphasized that the world will need to make substantial reductions in greenhouse gas emissions below current levels over the next few decades if the worst impacts of dangerous climate change are to be avoided. [EurekAlert!]
• 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: Climate Sensitivity

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’s 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:

• 20-23 September 1942…A rainstorm deluged the Maritime Provinces. Four-day totals 13.99 inches at Stellarton, Nova Scotia and 10.83 inches at Charlottetown, Prince Edward Island. Halifax, Nova Scotia recorded 9.40 inches of rain on the 21 September climatological day. (The Weather Doctor)
• 20 September 1967...Hurricane Beulah moved into South Texas, spawning a record 115 tornadoes for a hurricane. (David Ludlum) (Intellicast)
• 20 September 1973...Britain's greatest September daily rainfall floods Kent with 7.51 inches of rain. (The Weather Doctor)
• 22 September 1913...Des Moines, IA experienced their earliest freeze of record. (The Weather Channel)
• 22 September 1934...Edmonton, Alberta reported its greatest September snowstorm to date with 8.7 inches of snow. (The Weather Doctor).
• 23 September 1904...The temperature at Charlotteburg, NJ dipped to 23 degrees, the lowest reading of record for so early in the autumn for the state. (The Weather Channel)
• 24 September 1888...The earliest frost of record hit the southern states covering South Carolina, Georgia and northern Florida (Intellicast)
• 24 September 1926...The temperature at Riverside Ranger Station in Yellowstone Park dipped to nine degrees below zero, the lowest reading of record in the U.S. during September. (This record was broken by a 15 degree below zero reading at Big Piney, WY in September 1983.) Severe freezes were widespread over the northwestern U.S. causing great crop destruction. In Washington State, Spokane County experienced their earliest snow of record. Harney Branch Experiment Station in Oregon reported a temperature of 2 degrees above zero to establish a state record for the month of September. (David Ludlum) (The Weather Channel)
• 24-26 September 1950...A smoke pall from western Canada forest fires covered much of the eastern U.S. Daylight was reduced to nighttime darkness in parts of the Northeast. The color of the sun varied from pink to purple, blue, or lavender. Yellow to gray-tan was common. (24th-30th) On the 26th, residents of the northeastern U.S. observed a blue sun and a blue moon from the smoke. (David Ludlum) (The Weather Channel)
• 25 September 1939...A West Coast hurricane moved onshore south of Los Angeles bringing unprecedented rains along the southern coast of California. Nearly five and a half inches of rain drenched Los Angeles during a 24-hr period. The hurricane caused $2 million in damage, mostly to structures along the coast and to crops, and claimed 45 lives at sea. "El Cordonazo" produced 5.66 in. of rain at Los Angeles and 11.6 in. of rain at Mount Wilson, both records for the month of September. (David Ludlum) (The Weather Channel)
• 26 September 1963...San Diego, CA reached an all-time record high of 111 degrees. Los Angeles hit 109 degrees. (David Ludlum)

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Prepared by Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2010, The American Meteorological Society.