摘要:

Oceanographers have been accused of not thinking big enough. Where is our Hubble Space Telescope? Where is our Superconducting Super Collider? Where is our project to map the human genome? An example of a highly successful “big” project in the marine sciences is the Ocean Drilling Program, currently funded at about $42 million per year. That effort is small by comparison to big projects in astronomy and in highenergy physics.Ocean‐ice‐atmosphere interactions in polar regions play a major role in driving deep ocean circulation and in regulating Earth's climate, and Arctic regions in particular are expected to be the first to respond to the predicted global warming. Despite the fundamental importance of polar regions to the habitability of planet Earth, most oceanographers have used only the most inefficient methods for exploring the ocean beneath the ice: drifting on floating ice camps and bashing through the ice with ice breakers. Neither of these methods is an effective way to explore a feature as large and as physiographically varied as the Arcti

ISSN:0002-8606    

DOI:10.1029/91EO00169

年代:1992

数据来源: WILEY

摘要:

NASA scientists have found that the degree of Arctic ozone depletion over parts of the United States, Canada, Europe, and Russia was lower than expected this past winter, despite record levels of chlorine monoxide, the dominant form of active chlorine that destroys ozone, and other ozone‐depleting chemicals measured in the stratosphere. The findings were presented at NASA Headquarters in Washington, D.C., on April 30.Ozone depletion does however remain a threat in the future, said Joe Waters of the Jet Propulsion Laboratory in Pasadena, Calif., because chlorine sources are long‐lived in the stratosphere. “With so much chlorine in the stratosphere, a slight temperature difference can make an enormous difference in the potential for ozone depletion,”

ISSN:0002-8606    

DOI:10.1029/91EO00171

年代:1992

数据来源: WILEY

摘要:

Mexico has two kinds of groundwater problems. The first, which is common to many nations, includes groundwater contamination, saltwater intrusion, and severe drawdown in aquifers. The second, which amplifies effects of the physical problems, is a lack of trained professionals in the hydrogeologic sciences. For a country with a population of more than 80 million inhabitants, this is a serious problem.Of the approximately 2 million km2of surface land in Mexico, at least 1.2 million km2 are of hydrogeologic interest. Almost 50% of the water used in Mexico comes from groundwater. In many areas, such as the Yucatan peninsula, groundwater is the only source of water available. Approximately 340 aquifers have been identified. Of these, eighty are over‐exploited, sixteen have salt water intrusion problems, ten have contamination problems, and five have land subsidence problems associated with groundwater extractions. Drawdowns range from a few meters to more than one hundred meters in the past 50 years in areas of northern Mexic

ISSN:0002-8606    

DOI:10.1029/91EO00174

年代:1992

数据来源: WILEY

摘要:

John W . Harshbarger, founder of the University of Arizona's Department of Hydrology and Water Resources, died October 10, 1991, at age 77. He joined AGU (Hydrology) in 1960.Harshbarger was regarded as one of Arizona's and the nation's leading experts in the field of water resources. He provided guidance and leadership in the development of water supplies nationally and internationally during a career that spanned nearly 5 decades. At the University of Arizona, Harshbarger served as head of the geology department from 1961 to 1966 and as head of the hydrology department from 1966 to 1967. During his tenure, Harshbarger, with assistance from the U.S. Geological Survey, organized the first academic program in the United States to combine teaching and research in all aspects of hydrology. Under Harshbarger's direction, the hydrology department achieved a national and international reputation for excellence.

ISSN:0002-8606    

DOI:10.1029/EO073i019p00212-01

年代:1992

数据来源: WILEY

摘要:

Polar snow and ice are among the most valuable, or perhaps are the most valuable, tools for reconstructing past climatic conditions. Glacial‐ice records large changes over time scales ranging from intraannual to glacial‐interglacial transitions. Changes in the ice are thought to largely reflect changes in atmospheric chemistry and dynamics resulting from variations in biogeochemical cycling due to climatic, and other, perturbations [Oeschger and Langway, 1989].However, two broad classes of processes, air‐to‐snow transfer and post‐depositional modification, combine to filter and potentially distort atmospheric signals before they can be preserved in the glacial record [Neftel, 1991]. Recognizing the critical need to understand air‐snow transfer and postdepositional modifications to unravel the climate information recorded in ice cores, the International Commission on Snow and Ice (ICSI) established a working group on Snow‐Atmosphere Chemical Exchange. With support from the National Science Foundation, Division of Polar Programs, the ICSI working group organized a workshop to develop a science plan for a 3‐ to 5‐year research effort focused on exchange processes. The workshop will follow the current Greenland Ice Sheet Project Two (GISP2) drilling effort at

ISSN:0002-8606    

DOI:10.1029/91EO00177

年代:1992

数据来源: WILEY

摘要:

A substorm workshop was held at the Geophysical Institute of the University of Alaska, Fairbanks, from September 18 to 21, 1991. Approximately thirty substorm researchers participated in the workshop, including twenty‐five from the United States, two from Canada, and one participant each from Germany, France, and Japan.The purpose of the workshop was to critically assess our understanding of the substorm phenomenon. To understand a substorm is to understand how the magnetosphere and ionosphere interact with each other in response to the ever‐changing conditions in the solar wind. A substorm is a global phenomenon involving coupling of the solar wind, the magnetosphere, and the ionosphere. The complexity of this coupled system is the main reason why it has been so difficult to establish the temporal and spatial connections between substorm features observed in the polar ionosphere and in the magnetosph

ISSN:0002-8606    

DOI:10.1029/91EO00179

年代:1992

数据来源: WILEY

摘要:

AGU congratulates the twenty‐eight distinguished scientists who were selected by a committee of their peers to be AGU Fellows in 1992. This selection was based on the individual attaining acknowledged eminence in a branch of geophysics.The number of Fellows selected annually is limited to no more than 0.1% of the AGU membership. The new Fellows are listed below along with citations recognizing their specific achievement

ISSN:0002-8606    

DOI:10.1029/91EO00182

年代:1992

数据来源: WILEY