In this Issue:



Issue No. 44, Summer 2003



New Sea Ice Index and Archives

A new product derived from satellite passive microwave data provides monthly images of ice extent and ice concentration, allowing researchers to track trends and anomalies over time. For instance, these images make it easy to compare the ice edge position in the Weddell sea in March 2002 and March 2003, or determine the total area of arctic ice in April 2002. The images are suitable for downloading and use in reports and presentations.

concentration anomolyThe Sea Ice Index contains monthly images of ice extent, with an overlay of the median for that month, images of ice concentration, and images showing trends and anomalies based on the period of record beginning in 1988. Plots showing trends in ice extent by month, with confidence intervals, are also available. Documentation (“Resources for Interpreting Sea Ice Trends and Anomalies”) helps users understand trends in the context of natural variability, and outlines some of the assumptions and limitations that accompany linear regression for trend analysis. Index archives extend back to 1987.

Image, left: Concentration anomalies for September 2002, a month in which ice extent reached a record minimum (see Serreze et al., 2003).

WIST application

The Web Image Spreadsheet Tool displays archived images quickly and easily, in a tabular format. Here ice extent and concentration for months in 2003 are compared with 2002. The line on the extent image shows the median extent for that month.

plot of Northern Hemisphere Extent Anomalies for March 2003

This plot of Northern Hemisphere Extent Anomalies for March, the month of maximum sea ice extent, shows a steady decrease for the period of SSM/I coverage (1987-2003).

Serreze, M.C., J. Maslanik, T.A. Scambos, F. Fetterer, J. Stroeve, K. Knowles, C. Fowler, S. Drobot, R. Barry, and T.M. Haran, A Record Minimum Arctic Sea Ice Extent and Area in 2002, Geophysical Research Letters, 3 (3): 1110, doi:10.1029/2002GL016406, 2003.


Polar Pathfinder Daily 25- km EASE-Grid Sea Ice Motion Vectors

NSIDC is pleased to announce the availability of sea ice motion vectors for the northern and southern polar regions. Daily raw ice motion vectors, computed from AVHRR, SMMR, SSM/I, and International Arctic Buoy Programme (IABP) buoy data, are provided in ASCII text format. Daily and mean ice motion grids are in two-byte integer format, projected to the NSIDC EASE-Grid; these grids combine data from all sensors from November 1978 through March 2003. Mean ice motion grids include yearly, monthly, and weekly means, and a mean for the entire time series. Browse images of mean grids are available in Portable Network Graphics (PNG) and Enhanced Postscript (EPS) formats.

The complete data set is available via ftp. NSIDC encourages users to register for ice motion data, in order to receive e-mail notification of data updates. Please contact NSIDC User Services for more information. Access the documentation and data.


Updated Bootstrap Data Set

NSIDC recently received updates to the “Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I” data set. The daily and monthly data now span 26 October 1978 through 30 September 2002 for both the northern and southern polar regions, and are available via ftp.


AMSR-E Data Available in June

The Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is a mission instrument launched aboard NASA’s Aqua satellite on 4 May 2002. The Aqua mission provides a multi-disciplinary study of the Earth’s atmospheric, oceanic, cryospheric, and land processes and their relationship to global change. With six instruments aboard, the Aqua satellite travels in a polar, sun-synchronous orbit.

NSIDC will archive and distribute all AMSR-E products, including Levels 1A, 2, and 3 data. Level-1A data are available as of 18 June 2003. Data is accessible via the Earth Observing System (EOS) Data Gateway (EDG) and via NSIDC’s Data Pool. Level 2A data will be available 1 September 2003. Level 2B and Level 3 data will be available 4 March 2004.

The AMSR-E instrument was developed by Mitsubishi Electric Corporation, through a contract with the Japan Aerospace Exploration Agency (JAXA), with close cooperation of U.S. and Japanese scientists. NSIDC also serves as a portal for AMSR-E validation data, which document the accuracy and precision of AMSR-E observations and their derived products. The validation effort includes three types of products: cryospheric data (snow, ice, and sea ice), rainfall data, and soil moisture data. NSIDC will archive and distribute many of these data, and will provide electronic links to those validation data archived elsewhere. Currently, AMSR validation data is only available to science team and validation team members. Further information can be found at NSIDC's AMSR validation Web site.


Data User Workshop

The NOAA National Environmental Satellite, Data, and Information Service (NESDIS) held a Data Users’ Workshop in Boulder, CO, on 11-12 June 2003. NESDIS is the parent organization of the NOAA National Data Centers (an NSIDC affiliate) and of offices that provide operational satellite data products. Panel discussions solicited users’ opinions on current NESDIS products and services and informed users of future capabilities, plans, and data sets. For more information, please visit the Workshop Web site.



NASA and the Russian Academy of Sciences are developing a Northern Eurasia Earth Science Partnership Initiative (NEESPI).
A sponsored Science Conference was held in Suzdal, Russia, on 21-25 April to lay out the elements of a Science Plan. Approximately 90 scientists attended, half from Russia and half from the U.S., Europe, Japan, and Ukraine.

The meeting sought to identify critical science questions and establish a program of coordinated research to improve understanding of the interactions between ecosystems, energy and water cycles, the atmosphere, and human dynamics in northern Eurasia. The goal is to support international science programs with particular relevance to U.S. global climate change research and funding priorities. For more information, please visit the NEESPI Web site.


Report on Global Glacier Recession Workshop

NSIDC’s Director, Roger Barry, convened an NSF-sponsored workshop on “Mapping Global Glacier Recession” in Boulder, on 16-18 March 2003. Concerns over the recent acceleration in the recession of mountain glaciers and ice caps brought together experts from 11 countries to consider improved mapping methods. In addition to invited papers and contributed posters, three working groups addressed the status of the Global Terrestrial Network for Glaciers (GTN-G) within GCOS/GTOS, the World Glacier Inventory/World Glacier Monitoring Service, and methods of glacier mapping with new technologies. The workshop revealed that the previously estimated number of glaciers worldwide and their calculated ice volume are undoubtedly too low, due to the omission of ice bodies around the Greenland and Antarctic ice sheets. For most mountain areas there is evidence of accelerated glacier loss over the last two to three decades. Participants recommended procedures to quickly increase the availability of digital data on glacier extent. A brief report on the workshop will be presented in EOS Transactions of AGU, as well as in a Glaciological Data Report on the workshop proceedings later in 2003.



NSIDC’s State of the Cryosphere Wins STC Web Award

The Rocky Mountain Chapter of the Society for Technical Communication (STC) holds an annual competition for online publications. This year’s winner, selected in January, was the State of the Cryosphere (SOTC) site. This site gives an overview of the change in mountain glaciers, ice shelves, sea ice, Northern Hemisphere snow, permafrost, and sea levels, and includes a glossary and references. The SOTC site was produced by Richard Armstrong and the NSIDC Communications Group, with contributions by Mark Dyurgerov, Mark Fahnestock, Christina Hulbe, James Maslanik, Mark Meier, Ted Scambos, Mark Serreze, Julienne Stroeve, and Tingjun Zhang. Congratualtions to all who contributed and to Michon Scott for presenting the site.


Antarctic Sea Ice Forecast

Scientists from Lamont-Doherty Earth Observatory of Columbia University have recently built a linear Markov model to forecast Antarctic sea ice concentration. The model was built in the space of multivariate empirical orthogonal functions (MEOFs). The researchers chose sea ice, surface air temperature, sea level pressure, and surface vector winds to define the state of the Antarctic climate. Using 21 years (1980-2000) of observational and reanalysis data, they calculated the MEOFs of the climate variables, and used the principal components of the leading modes to train the seasonally dependent transition matrices of the Markov model. This allowed them to determine the evolution of the climate state from one month to the next.

The model has successfully forecasted current abnormal high ice concentrations in the Weddell Sea and Ross Sea, and below normal ice concentrations in the Amundsen Sea and Bellingshausen Sea two seasons in advance. The seasonal ice forecast (up to 12 months) is updated monthly.


Cold Land Processes Experiment

The Cold Land Processes Field Experiment (CLPX) was designed to advance our understanding of the terrestrial cryosphere. Quantitative understanding of cold land processes over large areas will require 1) better understanding how cold land processes vary from local to larger scales, 2) representation of cold land processes in land-surface models, and 3) a breakthrough in large-scale observation of hydrologic properties, including snow characteristics, soil moisture, the extent of frozen soils, and the transition between frozen and thawed soil conditions.
The CLPX addresses several questions, including the effect of snow and frozen landscapes on water, energy, and carbon cycles; the spatial variability and scale of cryospheric variables; the rates of change of cold land processes; and the ability of remote sensing and modeling to accurately detect and predict cold land processes.

Scientists, including NSIDC researchers, have developed a comprehensive field experiment to address these questions. The experiment uses a set of nested study areas to permit a detailed examination of cold land processes, modeling, and measurement over a wide range of physiographic conditions and spatial scales. Within this framework, intensive ground, airborne, and spaceborne observations were undertaken, and land surface model data sets generated, to produce a comprehensive database.
Data were collected during the winter and spring of 2002 and 2003, and will be initially available to CLP science team members. The first data from the 2002 field studies will be available to the public in October 2003.

NSIDC also hosted the 9th Workshop of the Cold Land Processes Working Group in 2003. A detailed catalog of metadata describing all the data collected in the experiment was released at this workshop. Participants of the workshop also reviewed and refined a new science plan for Cold Land Processes within NASA’s Earth Science Enterprise. Visit the CLPX Web site for the latest status of the data and to access the CLP metadata catalog.


Antarctic Features Sport New Names

Anarctic Features
view larger map


The Advisory Committee on Antarctic Names, a part of the USGS that assigns names to geographic features on the southern continent, has proposed a host of new names for features, some of them previously unnamed, and some of them with informal names such as Ice Stream “A” or Ridge “B/C.” The new names honor American glaciologists who participated in a twenty-year study of the dynamic West Antarctic Ice Sheet. The names are expected to be formally approved within the next few weeks.

Among the honorees is Dr. Ted Scambos of NSIDC. Former honorees also affiliated with the University of Colorado or CIRES are Dr. Mark Meier and Dr. John Behrendt from the Institute for Arctic and Alpine Research (INSTAAR), and Dr. Susan Solomon of NOAA’s Aeronomy Laboratory. The image above includes most of the newly named areas.