DataStreme ECS WEEK TWO: 13-17 September 2010

ITEMS OF INTEREST

• Follow a research cruise -- Dr. Jim Brey, Director the American Meteorological Society's Education Program, is currently participating on a 12-day research cruise called "School of Rock 2010" on the waters of the eastern North Pacific off the coast of British Columbia's Vancouver Island on the research vessel JOIDES Resolution. This vessel is operated by the Joint Oceanographic Institutions for Deep Earth Sampling (JOIDES) will be conducting drilling operations along the Cascadia fault. He will be posting a blog describing his onboard experiences. [JOIDES Resolution website]
• Eye on the tropics --
The historic or statistical annual peak in the Atlantic hurricane season occurred at the end of last week (10-12 September), as determined as the date during the entire season with most frequent number of named tropical cyclones (tropical storms and hurricanes), based upon over 100 years of record. This date corresponds closely with the time of peak sea-surface temperatures across those sections of the North Atlantic considered hurricane-breeding areas. [NWS National Hurricane Center] [Note: So far this Atlantic hurricane season, which commenced on 1 June 2010, four tropical cyclones have reached hurricane status including the currently active Hurricane Igor, five have were tropical storms, while three systems have been tropical depressions. EJH]
• The legacy of an ice age --
An image obtained from the MODIS instrument onboard NASA's Aqua satellites shows North America's Laurentian Great Lakes, which were created after the Laurentide ice sheet receded at the end of the last Ice Age. These lakes contain approximately 20 percent of the Earth's freshwater and are under threat from runoff that could contribute to algae (phytoplankton) bloom. Water temperatures for the individual lakes reached record or near record levels during this past summer. The image was made when the region surrounding the Great Lakes was relatively cloud-free because of high atmospheric pressure located over the region. [NASA Earth Observatory]
• A view of Earth and Moon from afar --
An historic image of the Earth and Moon was obtained last May from an instrument onboard NASA’s Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft that was orbiting Mercury, the planet closest to the Sun. [NASA Earth Observatory]

CURRENT CLIMATE STATUS

• US Weather and climate reviewed for August and Summer 2010 -- Based upon preliminary data, scientists at NOAA’s National Climatic Data Center report that the recently concluded meteorological summer of 2010 (June, July and August) was the fourth warmest summer across the coterminous United States since sufficiently reliable climate records began in 1895. The Southeast region had the highest temperatures, while the Central and Northeast were third and fourth highest, respectively. In addition, August 2010 was also the seventh warmest August on record, with a monthly average temperature that was 2.2 Fahrenheit degrees above the 20th century (1901-2000) average. Essentially all states from the Rockies eastward to the Atlantic Seaboard experienced above to much above average August temperatures. The states along the Pacific Ocean and across the northern Rockies had generally below average temperatures.
  The nationwide August 2010 average precipitation was slightly (0.19 inches) below the 20th century average. The East North Central region recorded its second wettest summer (June through August) on record in 2010. Wisconsin reported its greatest statewide precipitation average for Summer 2010 in the last 116 years.. [NOAA News]

CURRENT CLIMATE MONITORING

• Detecting global fire hotspots from space -- Last month, the United Nations' (UN) Food and Agriculture Organization in cooperation with NASA has launched a new online fire detection system called Global Fire Information Management System (GFIMS) with daily interactive fire maps that will help firefighters and natural hazards managers improve response time and resource management. These maps, which are available on the Web are generated from fire data collected from the MODIS sensors on NASA's Terra and Aqua satellites. [NASA GSFC]
  An image was obtained early last week of Colorado's Fourmile Canyon Fire from the MODIS sensor on the Terra satellite. [NASA Earth Observatory] A MODIS image from the Aqua satellite shows numerous fires across Bolivia during the last week. [NASA Earth Observatory]
• Seasonal pollution changes over India documented by satellites --
Atmospheric scientists at the University of Illinois have analyzed data from a sensor onboard a NASA satellite covering a decade and found that surprising trends in the concentration, distribution and composition of natural and human-made airborne particulates or aerosols over the Indian subcontinent. Many of these aerosol pollutants are produced by human activity and appear to affect not only the environment but also are detrimental to human health. [University of Illinois 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

• Widespread irrigation results in cooling of some regions -- A hydrologist and climatologist with Columbia University’s Earth Institute and the NASA Goddard Institute for Space Studies claim that expanded irrigation around the globe for agriculture designed to feed the world's growing population appears to have cause a drop in local temperatures due to evaporative cooling. While they indicate that this cooling appears to be counteracting the climate effects associated with temperature increases on a global scale, too much irrigation will deplete the groundwater aquifers within the next several decades, resulting in major shortages in useable water along with a return to increased air temperatures. [The Earth Institute/Columbia University]

CLIMATE AND THE BIOSPHERE

• Beetle outbreaks in West appear to rise with the temperature -- US Department of Agriculture's Forest Service researchers and their colleagues at the Western Wildland Environmental Threat Assessment Center, the Canadian Forest Service and the University of Idaho, Moscow recently reported on the study they conducted across western North American forests and have found that increased potential for outbreaks of spruce and mountain pine beetles appears to have increased because of changes in climate that have resulted in higher temperatures across the West. [EurekAlert!]
• Any connection between wildfires and beetle attacks?
Forest ecologists from the University of Wisconsin and the US National Park Service vegetation management specialist at Yellowstone National Park created maps of forests near the park hard hit by the recent beetle outbreak and they compared these regions with maps of recent wildfires. Their preliminary analysis indicates that large fires do not appear to occur more often or with greater severity in forest tracts with beetle damage. Their results appear in a NASA video. [NASA GSFC]

CLIMATE FORECASTS

• Improved climate forecasts are sought -- The National Academy of Sciences recently released a report, entitled "Assessment of Intraseasonal to Interannual Climate Prediction and Predictability" that evaluates the current state of climate forecasts that are on time scales that range from the intraseasonal (from weeks to one or two months) to interannual (several years to decades) and calls for the improvement of climate forecasts using recommended strategies. The improved climate forecasts would provide guidance for important decisions regarding water management, agriculture, and energy. This NOAA-requested study was conducted by a 12-member panel. [NASA JPL]

PALEOCLIMATE RECONSTRUCTION

• Investigating the end of the last Ice Age -- Scientists at Columbia University's Lamont-Doherty Earth Observatory have been studying ice core records and the glacial moraines in New Zealand to determine the climatic conditions between 13,000 and 11,000 years ago, which corresponds to the ending of the last Ice Age. They found that New Zealand along with Antarctica in the Southern Hemisphere warmed while many areas of the Northern Hemisphere cooled during the Younger Dryas, an interruption in the glacial retreat called a "stadial." Two explanations to the apparently opposite temperature trends in the two hemispheres: have been proposed that involve a weakening of the Gulf Stream, with one explanation having the weaker ocean current change the prevailing winds pushing warm air and seawater southward, and the other one that triggers warm water to pool in the south. [The Earth Institute/Columbia University]

CLIMATE AND SOCIETY

• Community Climate Change Adaptation Initiative is funded -- NOAA’s National Sea Grant College Program announced that a $1.2 million has been awarded to the Community Climate Change Adaptation Initiative in order to assist the nation's coastal communities prepare for the impacts of climate change. Nearly 20 university based Sea Grant programs along the Atlantic and Gulf coasts, 7 programs along the Pacific and 7 programs along the Great Lakes will running demonstration projects. These programs are intended to help communities along the oceans and the Great Lakes develop strategies to address coastal inundation, sea-level rise, drought, more frequent and intense coastal storms, and other impacts associated with climate change. [NOAA News]
• Main climate threat from future carbon dioxide sources --
Scientists from the Carnegie Institution and Quebec's Concordia University warn that the output statistics from their experiments on a global climate model using projected amounts of carbon dioxide from existing energy infrastructure worldwide would indicate that the devices whose emissions would cause the worst climate impacts have yet to be built. [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]

COMPARATIVE PLANETOLOGY

• Lander data helps shed light on water and volcanoes on Mars -- Scientists from NASA's Jet Propulsion Laboratory and the University of Arizona report that data obtained from the NASA Phoenix Mars Lander indicate that liquid water may have interacted with the Martian surface throughout the planet's history, including during modern times. In addition, the data provides evidence that volcanic activity on Mars has persisted through at least several million years ago, considered geologically recent times. [NASA JPL]
• Earthweek --
Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Feedback in Earth’s Climate System

In Earth’s climate system, feedback consists of a process where a change in one variable interacts with other variables of the system to alter that original variable. If the change reinforces the original quantity, it is known as a positive feedback. If the change suppresses the original quantity, it is a negative feedback. Feedbacks in Earth’s climate system are significant—thought to be responsible for more than half the global warming expected from human activities.

Consider examples of positive and negative feedback. A warming trend in climate is likely to accelerate the rate of melting of snow and ice, producing more bare ground that absorbs more solar radiation, further raising the air temperature. A cooling trend prolongs snow and ice cover in spring and summer so that less solar radiation is absorbed, more reflected to space, bringing about additional cooling. In both cases, feedback is positive because the initial change in temperature is amplified.

Consider an example of negative feedback. While feedbacks among temperature, cloud cover, and radiation are not well understood and depend upon circumstances (e.g., type and height of clouds), they could be either positive or negative. It is thought that a warming trend in climate should increase the rate of evaporation of water from Earth’s surface and thereby increase low cloud cover. A thicker and more extensive low-cloud cover reflects more solar radiation to space thereby inhibiting a further rise in surface temperature. Hence, this negative feedback would dampen the initial temperature change.

Understanding feedback in the climate system is essential for modeling and predicting climate change. If some agent or mechanism alters the climate, then feedback may either amplify (positive feedback) or dampen (negative feedback) the change in climate. As demonstrated later in this course, many agents and mechanisms can bring about climate change (e.g., variations in solar energy output, regular fluctuations in Earth-Sun geometry). While these climate forcing agents and mechanisms drive climatic change, processes within the planetary climate system involving feedbacks significantly impact the magnitude of climate change.

Overall, which type of feedback prevails in Earth’s climate system, positive or negative? A system in which positive feedback prevails is unstable. For Earth, this would move the climate regime toward an extreme characterized by excessive cold that would encase the planet in snow and ice ("snowball" or "ice ball" Earth) or toward the other extreme resulting in much higher temperatures—the product of a runaway greenhouse effect. Although Earth’s climate has varied considerably over the billions of years that constitute geologic time, it appears likely that Earth’s climate system has been nearly stable with negative feedbacks generally compensating for positive feedbacks.

Concept of the Week: Questions

Place your responses on the Chapter Progress Response Form provided in the Study Guide.

1. The magnitude of a climate change [(largely depends upon)(is independent of)] positive and negative feedback phenomena operating in Earth’s climate system.
2. Through much of Earth history, it appears that [(positive feedbacks)(negative feedbacks)(a general balance between positive and negative feedbacks)] have (has) prevailed.

Historical Events:

• 13 September 1922...The temperature at El Azizia in Libya soared to 136 degrees to establish a world record at a surface weather station. To make matters worse, a severe ghibi (dust storm) was in progress. (The Weather Channel) (NCDC)
• 13 September 1988...Hurricane Gilbert smashed into the Cayman Islands, and as it headed for the Yucatan peninsula of Mexico strengthened into a monster hurricane, packing winds of 175 mph. The barometric pressure at the center of Gilbert reached 26.13 inches (888 mb), an all-time record for any hurricane in the Caribbean, Gulf of Mexico, or the Atlantic Ocean. Gilbert covered much of the Gulf of Mexico, producing rain as far away as the Florida Keys. (The National Weather Summary) (Storm Data)
• 14 September 1937...The mercury soared to 92 degrees at Seattle, WA, a record for September. (The Weather Channel)
• 14 September 1970...The temperature at Fremont, OR dipped to 2 degrees above zero to equal the state record for September set on the 24th in 1926. (The Weather Channel)
• 14 September 1987...Barrow, AK received 5.1 inches of snow, a record for September. (Sandra and TI Richard Sanders - 1987)
• 14 September 1988...Pressure in the eye of Hurricane Gilbert moving across the Caribbean Sea fell to 885 millibars (26.17 inches of mercury), the lowest recorded barometric pressure in the Western Hemisphere. Ultimately, 318 died in seven countries across the Caribbean and Gulf of Mexico.
• 15 September 1939...The temperature at Detroit, MI soared to 100 degrees to establish a record for September. (The Weather Channel)
• 15 September 1982...A snowstorm over Wyoming produced 16.9 inches at Lander to establish a 24-hour record for September for that location. (13th-15th) (The Weather Channel)
• 16 September 1881...Iowa's earliest measurable snow of record fell over western sections of the state. Four to six inches was reported between Stuart and Avoca. (The Weather Channel)
• 16 September 1964...The temperature at Concord, NH dropped to 27 degrees ending the shortest growing season on record (100 days). (Intellicast)
• 16 September 1988...Hurricane Gilbert made landfall 120 miles south of Brownsville, TX in Mexico during the early evening. During its life span, Gilbert established an all-time record for the Western Hemisphere with a sea-level barometric pressure reading of 26.13 inches. Winds approached 200 mph, with higher gusts. Gilbert devastated Jamaica and Mexico's Yucatan Peninsula. (The National Weather Summary) (Storm Data) (The Weather Channel)
• 16 September 2004, Birmingham, Alabama: Birmingham, AL set two all-time records for the city as Hurricane Jeanne crossed the city: Lowest sea level pressure on record, 986.8 millibars (29.14 inches of mercury), and the greatest 24-hour rainfall event on record, 9.75 inches. (The Weather Doctor)
• 17 September 1829...The Siebold Typhoon, Japan's most catastrophic typhoon, inflicted widespread damage over much of Japan. On the southern island of Kyushu, the storm surge off the Ariake Sea kills 10,000. (The Weather Doctor)
• 17 September 1932...Westerly, RI received 12.13 inches of rain, which set a 24-hour precipitation record for the state. (NCDC)
• 17 September 1963...Nearly 2.5 inches of rain fell in 24 hours, the most intense rain for Yuma, AZ during the period between 1909 and 1977. (The Weather Doctor)
• 18 September 1991...2.4 inches of snow fell at Duluth, MN to set a new record for September. (Intellicast)
• 19 September 2004...The single-day rainfall record at Vancouver (British Columbia) International Airport was set 3.59 inches. The accumulation came in a month when rainfall is exceptional across the region. By mid-month, dozens of stations in British Columbia broke all-time September rainfall totals. (The Weather Doctor)

Return to DataStreme Atmosphere website

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