Arctic Oscillation

Topic(s):

No topics assigned.

Scenario:

The Arctic Oscillation (AO) is an important feature of the arctic atmosphere and its connections to global climate. The AO is a seesaw pattern in which the pattern of sea level pressure (SLP) at the polar and middle latitudes in the north hemisphere fluctuates between a "positive phase" and a "negative phase." The positive phase is characterized by higher pressure at mid-latitudes and lower pressure over polar regions. In the negative phase, the pattern is reversed.

For much of the past century, the AO had been switching back and forth between the two phases. Starting in the 1990s, however, the AO has been mostly in the positive phase, resulting in below-normal Arctic air pressure and subsequent changes in weather and climate patterns around the Northern Hemisphere. Impacts of the AO are seen in the intensity of winter weather, frequency or severity of winter storms, timing and volume of river runoff, and numbers of various fish. Scientists estimate that AO cycles can run on scales of 10 to 40 years.

Part of the AO story comes from "Igor Poylakov, a Russian oceanographer working at IARC [International Arctic Research Center]. He first found the trace of a sixty to eighty-year cycle of the Arctic Ocean's sea ice in a model he built on his computer workstation, a finding he published in 2000. After seeing the pattern in the computer, Igor and his colleagues confirmed it in Arctic weather data gathered near the ocean's edge around the globe. Temperatures reached a peak in the late 1930s and early 1940s, dropped to a low in the 1960s and 1970s, and looked to be ready to peak again. Igor named this climate signal the Low Frequency Oscillation, or LFO. He theorized that the Arctic Ocean could be acting like a clock regulator in response to climate kicks from the North Atlantic. Using sophisticated statistical techniques, Igor and his colleagues subtracted the LFO from the overall warming trend in the Arctic going back to 1875 and found that it erased the Arctic amplification found in theory and models. (pp 173-174).

Research by Mike Wallace and David Thompson at the University of Washington suggested that much of the observed warming could have been caused by the AO's patterns of circulation. Following their lead: "Scientists found correlations to other Arctic phenomena that lined up with the high AO index, including thinner sea ice. Journalists were excited by the contrarian idea that atmospheric circulation rather than global warming could be responsible for the changes seen in the Arctic, and the Arctic Oscillation swept into some popular writing as a debunker of climate change" (p 175).
From the Google Books Preview "The Whale and the Supercomputer."
Click here for the Amazon reviews of this book.

The AO extends through the stratosphere six to 30 miles above the earth. When the AO changes phases, the strengthening or weakening of the circulation around the North Pole begins in the stratosphere and works its way down through the lower atmospheric levels. This is the opposite of El Nino, where most often changes begin in the ocean and work their way upward through the atmosphere.

Task:

Basic Tasking: Given that the AO has been mostly in the positive phase since the 90s, your group's ESS analysis will provide policy makers with information concerning the impact of a switch to a mostly negative phase.

Comprehensive Tasking: The IPCC has been looking at the results of researchers such as Igor Poyakov and others. They want to know if the changes in the Arctic reflect anthropogenic influences or whether the changes are simply part of a longer-term natural cycle e.g. eighty years or more. Your analysis of this hypothesis will provide policy makers with suggestions about what might happen if for example, the retreat of sea ice reverses itself.

Date: 6/3/2009

Scenario Images:

Images Courtesy: J. M. Wallace, University of Washington.

The Arctic Oscillation (AO) index describes the relative intensity of a semipermanent low-pressure center over the North Pole. A band of upper-level winds circulates around this center, forming a vortex. When the AO index is positive and the vortex intense, the winds tighten like a noose around the North Pole, locking cold air in place. The stronger polar vortex of the Arctic Oscillation's positive phase (top) brings cool winds across eastern Canada, while North Atlantic storms bring rain and mild temperatures to northern Europe and drought conditions prevail in the Mediterranean region. The weaker polar vortex of the negative phase allows cold air to plunge into the midwestern United States and western Europe, and storms bring rain to the Mediterranean."

The Arctic Oscillation in Winter. Visit this NOAA site for more Arctic Oscillation links.

Resources:

Arctic Climate Impact Assessment (Cycle A)
An international project of the Arctic Council and the International Arctic Science Committee (IASC), to evaluate and synthesize knowledge on climate variability, climate change, and increased ultraviolet radiation and their consequences. The results of the assessment were released at the ACIA International Scientific Symposium held in Reykjavik, Iceland in November 2004. Going first to the index may be the quickest way to find something.

Arctic Climatology and Meteorology PRIMER for Newcomers to the North (Cycle A)
This National Snow and Ice Data Center site contains links to the "basics of arctic weather," "the factors that determine weather and climate," and some of the "weather patterns in the Arctic." This site may fill in needed background information on Arctic weather and climate.

Arctic decadal and interdecadal variability (Comprehensive) (Cycle A)
"...results suggest that the decadal AO and
multidecadal LFO drive large amplitude natural variability in the Arctic making detection of possible long-term trends induced by greenhouse gas warming most dicult."

Arctic Forecast: Nordic Sea Ice Expansion (Comprehensive) (Cycle A)
"In an article recently appearing in the Journal of Geophysical Research, Dmitry Divine and Chad Dick (2006) of the Norwegian Polar Institute report on their use of historical observations of ice cover in the Nordic Seas region to construct time series of warm season ice edge position dating back to 1750."

Climate Indicators -- ArcticOscillation (Cycle A)
"A Near-Real time Arctic change indicator website with information about th AO and surface and stratospheric temperatures, clouds and ocean. The site is a contribution to the Study of Environmental Arctic Change (SEARCH).

Evidence Mounts for Arctic Oscillation's Impact on Northern Climate (Cycle A)
From three of the more prolific and cited Arctic researchers at the University of Washington. A growing body of evidence indicates that a climate phenomenon called the Arctic Oscillation has wide-ranging effects in the Northern Hemisphere and operates differently from other known climate cycles. The evidence indicates the acceleration of a counterclockwise spinning ring of air around the polar region could be responsible for warmer winters in Scandinavia and Siberia, thinning of the stratospheric ozone layer, and significant changes in surface winds that might have contributed to Arctic ice thinning."

NASA: Arctic Ocean Circulation Reversal Not Due to Global Warming (Cycle A)
"A study published in Geophysical Research Letters by NASA scientists shows that weakening of the Arctic Oscillation results from a cyclical process rather than climate change. The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming."

Thompson and Wallace Paper Linking Arctic AO to Climate Change (Cycle A)
This paper cites evidence indicating "that the stratospheric polar vortex in implicated in some of the interannual and secular variability at the Earth's surface."

Why We Study Arctic Climate Change (Cycle A)
Background on Arctic climate and the impacts seen there in recent years. This NOAA site introduces the Pacific Decadal, Arctic, and North Atlantic Oscillations. There are also a set of hyperlinks to related materials.

Arctic Oscillation (AO) time series, 1899 - June 2002 (Cycle B)
This is the data for Arctic Sea Level Pressure, precipitation and surface air temperature anomalies.

NOAA Paleoclimatology Program Archives (Cycle B)
"The NOAA Paleoclimatology Program archives reconstructions of past climatic conditions derived from paleoclimate proxies, in addition to the Program's large holdings of primary paleoclimatic proxy data. Included are reconstructions of past temperature, precipitation, vegetation, streamflow, sea surface temperature, and other climatic or climate-dependent conditions. "

Pinatubo's Eruption May Have Influenced Climate Through the Arctic Oscillation (Cycle B)
"A recent NASA-funded study has linked the 1991 eruption of the Mount Pinatubo to a strengthening of a climate pattern called the Arctic Oscillation. For two years following the volcanic eruption, the Arctic Oscillation caused winter warming over land areas in the high and middle latitudes of the Northern Hemisphere, despite a cooling effect from volcanic particles that blocked sunlight."

Researchers Sweat Out Global Warming (Cycle B)
A somewhat older article but still pertinent in discussing world wide climate trends along with scientists' opinion on what it all could mean.

Variability of the Arctic Ocean over the Last 100 Years (Comprehensive) (Cycle B)
What impact would changes in density have in the flow of Atlantic water to the Arctic Ocean? This research article addresses the Arctic atmospheres-ice-ocean system: "Over recent decades, the data show a warming and salinification of the Atlantic layer accompanied by its shoaling and, probably, thinning.
The estimate of the Atlantic water temperature variability shows a general warming trend; however, over the 100-yr record there are periods (including the recent decades) with short-term trends strongly amplified by multidecadal variations. Observational data provide evidence that Atlantic water temperature, Arctic surface air temperature, and ice extent and fast ice thickness in the Siberian marginal seas display coherent LFO. The hydrographic data used support a negative feedback mechanism through which changes of density act to moderate the inflow of Atlantic water to the Arctic Ocean, consistent with the decrease of positive Atlantic water temperature anomalies in the late 1990s.

Wind and Air Circulation Provide Background to Arctic Oscillation (Cycle B)
"Air pressure gradient, or the difference between regions of high and low air pressure, impels air in the direction of lowest pressure, creating wind. The larger the air pressure gradient, the greater the wind speed. Several other factors interact to affect wind speed and direction. The most important of these are the Coriolis effect and friction.

Arctic Ice Cap Radio Broadcast (Cycle C)
"This radio broadcast reports on how tourists and even some scientists aboard a Russian cruise ship in July 2000 were shocked to discover open water at the North Pole. However, scientists who study the Arctic say open water at the pole is a common occurrence. The broadcast discusses how much of the changes seen in the Arctic are a result of global warming versus the natural variability that has been going on for hundreds of years. The broadcast is 5 minutes in length."

Arctic Oscillation Caused Chill to Eastern U.S. During Winter 2010 (Cycle C)
Did all of your friends tell you that surely there is no global warming as evidenced by the frigid temperatures in the Eastern U.S. during January 2010?

Check this out!

Climate Change and Human Rights: Inuit Perspectives on a Global Issue (Cycle C)
"For the Inuit, climate change is an issue of cultural survival. Join Sheila Watt-Cloutier, Chair of the Inuit Circumpolar Conference (ICC), an organization representing the Inuit across the Arctic, as she explores the effects of climate change on her Arctic home."

Video Lecture on Arctic Climate Change (Cycle C)
"The Arctic is changing in dramatic and disturbing ways with giant lakes replacing what used to be ice fields. This video lecture presents data showing ice over the Arctic Ocean retreating over recent decades; military submarine data from under the Arctic ice showing the thickness of the ice decreasing everywhere over the last 50 years; and pictures 50 miles from the North Pole revealing open ocean where there was once ice. The percentage of glaciers that are retreating is explored, using the Hubbard Glacier in Alaska as an example. Models of climate warming and a Navy projection of where the ice will retreat to are also presented. The video is 16 minutes long."

Sample Investigations:

Evidence of Change Near the Arctic Circle (Cycle A)
The materials in this module suggest a warming trend in the Arctic, with warmer weather and thinning sea ice. Visit this My NASA Data site to investigate. "While you may be more familiar with daily weather patterns, scientists are more concerned with climate patterns and the changes that may be foreshadowed. Many claims have been made about the evidence for or against global warming, yet whether the interpretation of the data points leans towards fact or fiction, a more descriptive term to use is global climate change. The most hard-hit area where global climate change is apparent is within the Arctic Circle. In this lesson, you will explore data from the Arctic, develop relationships between parameters and make conclusions based on the collected evidence."
Difficulty: beginner

For K-4 Teachers: Kids Crossing: Living in the Greenhouse (Cycle A)
This site contains background on climate, as well as activities for younger students. The site may contain one of the most succinct explanations of the North Atlantic Oscillation and Arctic Oscillation for the lay person.
Difficulty: beginner

Arctic Climate Modeling Program (Cycle B)
A full range of activities on Arctic Climate for K-12 students. The ACMP program is funded through a grant from the National Science Foundation ITEST program, and is managed by the Geophysical Institute. Click on Curriculum Resources, then Climate Change for the materials related to Arctic climate.
Difficulty: beginner

Arctic Climate Perspectives (Cycle B)
The global climate is changing at a rapid pace. Although historical environmental change could be attributed to natural causes, recent patterns indicate that human activities are the dominant factor in the current change in climate. This video, adapted from material provided by the ECHO partners, shows the changes now happening in Barrow, Alaska, due to global warming.
Difficulty: beginner

Meterology: Inquiry-Based Learning for Grades 5-9 (Cycle B)
Teachers wishing to have their students get deeper into meteorology will find this NASA resource very useful. "This product is written as a supplement to existing Earth and space science curricula for grades 5-9. The guide may be used in both formal and informal educational settings as well as at home. It should be used in conjunction with lectures, discussions, textbooks and other teaching material. This guide is not intended to be a complete course in meteorology; rather, its function is to assist educators in instilling excitement in learning about meteorology by permitting the learner to take increasing responsibility for his/her learning."
Difficulty: beginner

Go North for Arctic climate Impact (Cycle C)
Look at changes in the Arctic from the perspective of local people: "The Arctic is now experiencing some of the most rapid and severe climate change on earth. Over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social and economic changes, many of which have already begun. Changes in Arctic climate will also affect the rest of the world through increased global warming and rising sea levels." Arctic Climate Impact Assesement (2005)
Difficulty: beginner

NASA'a Global Climate Change: Vital Signs of the Planet (Cycle C)
A Jet Propulsion Laboratory web site with key indicators on global climate change. These include Arctic Sea Ice, Carbon Dioxide, Sea Level, Global Temperature and Ozone Hole. While the site is not an activity, it would serve as a very useful resource for student looking for data in support of a global climate change investigation.
Difficulty: beginner

Standards:

• Science
  National Science Education Standards - Science Content Standards http://www.nap.edu/readingroom/books/nses/html/overview.html#content The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.
  • K-12 UNIFYING CONCEPTS AND PROCESSES
    The understandings and abilities associated with the following concepts and processes need to be developed throughout a student's educational experiences:
    • Systems, order, and organization
    • Evidence, models, and explanation
    • Constancy, change, and measurement
  • GRADES 9-12 CONTENT STANDARDS
    • Science as Inquiry (Std A)
      • Abilities necessary to do scientific inquiry
      • Understanding about scientific inquiry
    • Physical Science (Std B)
      • Interactions of energy and matter
    • Earth and Space Science (Std D)
      • Energy in the earth system
    • Science and Technology (Std E)
      • Understanding about science and technology
    • Science in Personal and Social Perspectives (Std F)
      • Environmental quality
      • Natural and human-induced hazards
      • Science and technology in local, national, and global challenges
• Geography
  Geography for Life: National Geography Standards, 1994
  • THE WORLD IN SPATIAL TERMS
    Geography studies the relationships between people, places, and environments by mapping information about them into a spatial context. The geographically informed person knows and understands:
    • How to use maps and other geographic representations, tools and technologies to acquire, process, and report information from a spatial perspective
  • PLACES AND REGIONS
    The identities and lives of individuals and people are rooted in particular places and in those human constructs called regions. The geographically informed person knows and understands:
    • The physical and human characteristics of places
    • That people create regions to interpret Earth’s complexity
  • PHYSICAL SYSTEMS
    Physical processes shape Earth’s surface and interact with plant and animal life to create, sustain, and modify ecosystems. The geographically informed person knows and understands:
    • The physical processes that shape the patterns of Earth’s surface
    • The characteristics and spatial distribution of ecosystems on Earth’s surface
  • HUMAN SYSTEMS
    People are central to geography in that human activities help shape Earth’s surface, human settlements and structures are part of Earth’s surface, and humans compete for control of Earth’s surface. The geographically informed person knows and understands:
    • The characteristics, distribution, and migration of human populations on Earth’s surface
    • The processes, patterns, and functions of human settlement
  • ENVIRONMENT AND SOCIETY
    The physical environment is modified by human activities, largely as a consequence of the ways in which human societies value and use Earth’s natural resources, and human activities are also influenced by Earth’s physical features and processes. The geographically informed person knows and understands:
    • How human actions modify the physical environment