SUBTASK 7.2 GLOBAL WARMING AND GREEHOUSE GASES

Solc, Jaroslav ; Eylands, Kurt ; Jr., Jaroslav Solc

University of North Dakota

关键词: Watersheds;    Greenhouse Effect;    Gases;    Salinity;    Droughts;   

DOI  :  10.2172/841343
RP-ID  :  NONE
RP-ID  :  FC26-98FT40320
RP-ID  :  841343

美国|英语

来源: UNT Digital Library

【 摘 要 】

Evaluation of current climatic trends and reconstruction of paleoclimatic conditions for Devils Lake have been conducted based on diatom-inferred salinity for the last 2000 years. The 3-year cross-disciplinary research, funded by the U.S. Department of Energy (DOE) was carried out by the Energy & Environmental Research Center (EERC) and St. Croix Watershed Research Station (SCWRS) at the Science Museum of Minnesota. The results indicate that frequent climatic fluctuations resulting in alternating periods of drought and wet conditions are typical for the northern Great Plains and suggest that the severity and length of extremes exceeded those on modern record. Devils Lake has experienced five fresh periods and two minor freshening periods in the last 2000 years. Transitions between fresh and saline periods have been relatively fast, representing lake level changes that have been similar to those observed in the last 150 years. From 0 to 1070 A.D., Devils Lake showed more variable behavior, with fresh phases centered at 200, 500, 700, and 1000 A.D. From 1070 A.D. to present, Devils Lake was generally saline, experiencing two minor freshening periods at 1305-1315 and 1800-1820 A.D and the major current freshening from 1960 A.D. to present.