IPY Data Sets at the Alaska Satellite Facility (ASF): RADARSAT-1

EarthzineArticles, Earth Observation, Original, Sections

Rebecca Sanches and Nettie La Belle-Hamer, Ph.D.

University of Alaska Fairbanks (UAF)/Geophysical Institute (GI)/ASF

Like a canary in a mineshaft, the Earth’s polar regions display the effects of climate change sooner than other places on Earth. International Polar Years (IPY) are specific time frames chosen to gather diverse data sets to examine these effects. The current IPY, 2007-2009, marks the fourth time researchers have planned large scale coordinated research campaigns designed to gain a better understanding of the polar regions and their effect on the global community. In the first IPY, held in 1882-1883, polar research was focused in the northern hemisphere and involved 12 countries. The spirit of IPY was evident by the number of scientific breakthroughs that were made. It was the first time an international research community had ever attempted such a project, setting a

Tilted image of Greenland Glaciers Image R125279273G0S001 from ASF
Figure 1. Greenland Glaciers Image R125279273G0S001

from ASF.

precedent for generations of researchers to follow.

The second IPY, held in 1932-1933 in the midst of a worldwide economic depression, took advantage of technological advances that occurred since the first IPY. The invention of radio technology, motorized vehicles, and aircraft enabled researchers to travel farther, allowing more to be accomplished in a shorter period of time. In the time between the first and second IPY, the global human population nearly doubled. As a result of this and other human and non-human impacts, environmental changes were occurring rapidly. Researchers made many observations from aircraft, marking the beginning of the use of remote-sensing technology that would grow into what is now a common, cost-effective way to do research.

The Great Depression affected the viable funding sources available for basic research. The very occurrence of the second IPY is a testament to the dedication of the researchers and the interest in expanding knowledge of the environment near the poles. Forty-four countries went on to do research thanks to philanthropic contributions and dedication from the science community.

In 1952, the influential Physicist, Lloyd Viel Berkner, saw the upcoming maximum in the sunspot cycle as an opportune time to create a series of comprehensive global geophysical measurements. The range of research broadened and grew into what became the first International Geophysical Year (IGY), 1957-1958. The concept of World Data Centers and legacy data sets was born. The IGY, 75 years after the first IPY, celebrated the anniversaries of the previous two IPYs. It was an 18 month systematic study of the Earth from pole to pole that began in 1957. Modeled after previous IPYs, the IGY was highly successful thanks to dedicated researchers, advancements in technology, and research practices stemming from the maturing capabilities found in post-war years.

The understanding of the Earth and its processes were improved as researchers collaborated on both data collection and analysis. While the work was carried out globally, there was increased interest in the poles, especially in the Antarctic region. Research opportunities drew people to Antarctica and they arrived in numbers greater than ever. IGY was a clear-cut success and paved the way for scientists who look to the poles to understand global and regional geophysical changes.

Dr. Roger Smith, current Director of the GI at UAF, was an undergraduate student during the IGY. When asked what he thought was the biggest advancement since IGY, he had this to say: “Undoubtedly, it’s the fact that we now have satellites. Satellites enable us to have a global view of anything we can record from satellite altitudes. We have more scope and it is orders of magnitude more scope”.

The current IPY continues the interdisciplinary science and the spirit of international cooperation established in the IGY. Today, with more than 60 countries participating and over 200 IPY-related research projects underway, IPY is moving forward in its effort to facilitate our understanding of changes at the poles and how those changes affect the rest of the world. As a side effect, it is proving to be a catalyst to enhancing how satellite data is accessed by scientists.

In a joint project with the Canadian Space Agency, the National Aeronautics and Space Administration (NASA), and UAF, entitled the “Arctic Science Archive Processing (ASAP) Project”, RADARSAT-1 Synthetic Aperture Radar (SAR) data has been identified that will be useful to IPY researchers. The unique capability of SAR to image through any weather, day or night, makes these data sets especially valuable for polar studies. The data sets enable researchers to access information regarding dangerous or inaccessible areas and provide them the ability to see the effects of climate change in Arctic and Antarctic regions, without costly and risky expeditions. Figure 1 shows glaciers in Greenland, as seen by RADARSAT 1. Currently, RADARSAT-1 SAR data for United States’ (U.S.) researchers is restricted by foreign data policies and requires NASA approval for access. However, IPY legacy data sets are available to international researchers without restrictions.

Legacy data sets offer researchers access to both new and archival data. Their usefulness extends beyond IPY to provide a historical global view and a frame of reference for future projects. ASF’s goal is to continue to make these data sets available beyond the current IPY to a new generation of researchers interested in studying the Arctic or Antarctic.

As technology improves, scientists are discovering new ways to apply SAR to their research. SAR has proven to be an invaluable tool in measuring geophysical dynamics. While this article is focused on RADARSAT-1 for IPY distribution, valuable data sets from the polar orbiting satellites JERS-1, ERS-1, ERS-2, AIRSAR, and ALOS (both SAR and optical sensors) are also available through ASF. Other legacy data sets will be offered as a part of IPY such as ALOS data over the Antarctica. These data are being made available through collaborative efforts by the Japan Aerospace Exploration Agency and the European Space Agency. This partnership will be described more thoroughly in a subsequent article.

These data allow us to observe natural phenomena such as glacial and ice-shelf motions, wind effects on ocean surfaces, and regional flooding, on a large scale over long times. The data will be more valuable as we look back at climate change historically and as we prepare for the future. With regard to the future, Dr. Smith reminds us, “Now is the time to make plans for how we are going to be post-IPY. We have to find the people who are going to be our leaders post-IPY. This includes creating the legacy data sets for future investigators who will further our understanding of climate change”. As Dr. Smith asserts, doing this is necessary to ensure the continuity of our research efforts after IPY concludes.

IPY legacy data sets:

- Greenland, Fine Beam, Level-0 and Level-1 products (Sept. 2000 – Jan. 2001)

- RADARSAT Antarctic Mapping Project data, Level-1 products (Sept.1, 1997 – Oct. 31, 1997)

- Toolik Station, Alaska, Standard Beams 1-7, Level-1 products (Oct. 2004 – Dec. 2006)

- Kamchatka Peninsula, Standard Beams 1-7, Level-1 products (Dec. 1999 – Jan. 2000)

- Bering Sea, ScanSAR Wide-B, Level-1 products (Sept./Mar. 2006, 2007)

Future IPY data sets from the Canadian RADARSAT-1 archive may include:

- Arctic Sea Ice, ScanSAR Wide-B, Level-1 products (Sept. - Mar. 2003 - 2007)

- Sea Ice Min and Max mosaics, ScanSAR Wide A&B (Sept - Mar. 2003 - 2007)

- Arctic Super Sites, ScanSAR Wide A&B (1996 - current)

- Great Slave Lake, ScanSAR Wide A&B (1996 - current)

- Great Bear in Level-1 ScanSAR Wide A&B (1996 - current)

- Northwest Territories, Standard Beams 1-7 (1996 - current)

- Mackenzie Delta, Fine, Wide, and ScanSAR, Level-1 products (1996 - current)

- Axel Heiberg, Fine-Beam, Level-0 products (Sept. 2000 - Feb. 2001)

ASF has made access to the data fast and simple. Access can be found at: www.asf.alaska.edu/ipy/ . For questions, please contact the ASF User Services Office via email at uso@asf.alaska.edu or by phone at (907) 474-6166.