Global Air-ocean IN-situ System


GAINS is a program which would develop the systems needed for an operational global in-situ observing system. The operational program, which would begin in 2006 is conceived as a network of high-tech balloons which could be evenly distributed over the global stratosphere at altitudes from 60,000 to 90,000 feet. The balloons would drift with the wind, but could be located as desired by a technique called "shear direction." The balloons are large, over 100 feet in diameter, and could carry payloads of over 500 lbs. They would typically carry small packages, "sondes" of many different types, which could be dropped on command to measure important atmospheric and ocean parameters. For example, the balloon could carry enough meteorological dropsondes to routinely provide accurate temperature, moisture and wind from the balloon height to the surface of the earth. A network of 400 balloons would provide twice daily measurements for virtually every 10 degree square of latitude and longitude over the entire globe. In addition, GAINS can measure other global quantities such as carbon dioxide, ozone, and subsurface ocean parameters. The balloons would be under continuous control, and could be, within less than a day, over any point on earth (e.g., over an erupting volcano or an oceanic algae bloom) with the ability to drop appropriate sensors. The balloons, early versions of which are currently being tested, can be thought of as a network of very low orbit satellites. They offer tremendous potential for US leadership in industries like global communications.

GAINS would result in a big improvement of weather prediction for the globe. Weather prediction beyond a day or two depends on the global upper atmospheric observing system. The current global upper atmosphere observing system is dominated by two systems. The first, balloons released twice a day from land areas, has always had limited coverage of the globe, typically including none of the oceans, and on land, only the countries rich enough to afford them. This situation is getting worse, because countries like the former Soviet Union, Canada, Mexico and others are reducing coverage for budget reasons. Others, like the Europeans, are threatening to limit availability of data. Over the oceans, we have depended on satellites for upper air data. However, satellite data is limited in accuracy in the lower atmosphere because of the overlying air, and is limited in its resolving power. Theory indicates that very accurate in-situ measurements like those provided by GAINS would be the ideal complement to the global satellite upper air observing system.

GAINS would be a crucial system for determining global change in the 21st century. A great scientific and policy issue for the foreseeable future is the effect of humans on the planet's atmosphere and oceans. It has been argued that surface data (over limited land areas) indicate the globe is warming, while satellite data indicates the global atmosphere is cooling. The GAINS system will allow us to resolve this discrepancy.

Program: A seven year development program is required to make GAINS a potential operational system. NOAA's Forecast System Laboratory, New Mexico State University's Physical Science Laboratory and Global Solutions for Science and Learning have developed a plan which culminates in a global test of the system in the year 2004. It is assumed that the costs of the operational program would be shared among the world's nations.

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Prepared by Randall Collander,
Last modified:Monday, May 14, 2001 17:33:31