SEARCH Projects

NOAA SEARCH Element 9: Monitoring the Eurasian Basin of the Arctic Ocean

Ignatius G. Rigor Andy Heiberg Doug R. Lamb Igor Polyakov Sergey Priamikov Institution: APL, University of Washington

Abstract

A network of automatic data buoys to monitor synoptic-scale fields of sea level pressure (SLP), surface air temperature (SAT), and ice motion throughout the Arctic Ocean was recommended by the U.S. National Academy of Sciences in 1974. Based on the Academy’s recommendation, the Arctic Ocean Buoy Program was established by the Polar Science Center (PSC), Applied Physics Laboratory (APL), University of Washington, in 1978 to sup-port the Global Weather Experiment. Operations began in early 1979, and the program continued through 1990 under funding from various agencies. In 1991, the International Arctic Buoy Program (IABP) succeeded the Arctic Ocean Buoy Program, but the basic objective remains – to maintain a network of drifting buoys on the Arctic Ocean to provide meteorological and oceanographic data for real-time operational requirements and research purposes including support to the World Climate Research Programme and the World Weather Watch Programme.

Dramatic changes in Arctic climate have been noted during the past two decades. Observations from the International Arctic Buoy Programme (IABP) have played a significant role in the detection of this change over the Arctic Ocean. For example, using IABP data, Walsh et al. (1996) showed that SLP has decreased; Rigor et al. (2000) showed that SAT has increased; and in concert, the circulation of sea ice and the ocean have changed so as to flow less clockwise (Steele and Boyd, 1998; Kwok, 2000; and Rigor et al. 2002). In addition to studies of Arctic climate and climate change, observations from the IABP are also used to validate satellites, for forcing, validation and assimilation into numerical climate models, and for forecasting weather and ice conditions.

The continued success of the IABP, and our ability to monitor many aspects of Arctic climate change, depend on maintaining and further developing the buoy network. The buoys drift with the sea ice and have finite life spans, so a tremendous amount of resources are required to purchase and deploy buoys to maintain the buoy network. In the past the IABP was able to seed the buoy network in the Beaufort Sea and the large clockwise gyre circulation would carry the buoys out to cover the Arctic Ocean. However, given the changes in circulation noted above, the Beaufort Gyre has shrunk, and maintaining the buoy network in the Eurasian Arctic has been more difficult. For example, the latest map of buoys on the Arctic Ocean shows that only 6 of the 26 buoys in the network are monitoring the Eurasian Basin. (Fig. 1.)

Monitoring the Eurasian Basin is important since this is the center of many of the changes in Arctic climate. For example, the decrease in SLP noted by Walsh et al. (1996), the warming in SAT noted by Rigor et al. (2000), and the thinning of Arctic sea ice noted by Rothrock et al. (1999) are most significant in this area. One could ask, did the increase in SAT act to thin sea ice, or did the thinner sea ice allow more heat to flux from the ocean to warm the atmosphere? It has been hypothesized that the dynamic thinning of sea ice driven by the changes in atmospheric circulation causes the increasing trends in SAT (e.g. Rigor, et al. 2002).

We propose to deploy enhanced buoys in the Eurasian Basin of the Arctic Ocean, which will monitor the thickness of sea ice to verify this hypothesis. Establishing a record of climate-induced changes in the thickness of the sea ice cover is essential to understanding the role of the sea ice cover in the global climate system and to the application of the sea ice cover as an early indicator of climate change in the Polar Regions. As explained in the recent report on the SEARCH Workshop on Large-Scale Atmosphere/Cryosphere Observations (Overland et al., 2002), buoys within the IABP network can play an important role in monitoring changes in ice thickness by enhancing their measurement system.