Hydroclimatic change in southern Manitoba
since A.D. 1409 inferred from tree rings.

Re River, Manitoba, aerial view looking North Hydroclimatic change in southern Manitoba
since A.D. 1409 inferred from tree rings.

Quaternary Research
Volume 58, pp. 103-111, September 2002.


Scott St. George
Geological Survey of Canada
Erik Nielsen
Manitoba Geological Survey

ABSTRACT:
A record of estimated annual (prior August to current July) precipitation derived from a regional bur oak (Quercus macrocarpa Michx.) tree-ring chronology indicates that southern Manitoba's hydroclimate has been relatively stable over the last 200 yr. Although this stability was interrupted briefly by pronounced wet intervals in the late A.D. 1820s and 1850s, hydroclimatic conditions since permanent Euro-Canadian settlement were much less variable and persistent than those prior to A.D. 1790. The reconstruction indicates that the Red River basin experienced extremely dry conditions between A.D. 1670 and 1775, with below-normal precipitation occurring approximately 2 years out of 3. Annual precipitation was estimated at more than two standard deviations below the mean during A.D. 1477, 1485, 1556, 1595, 1612, 1644, 1661, 1743, 1900, and 1980. Comparisons with limnological records from North Dakota and Minnesota suggest that multidecadal fluctuations in regional hydroclimate have been remarkably coherent across the northeastern Great Plains during the last 600 yr. However, individual dry years in the Red River basin were usually associated with larger scale drought across much of the North American interior.

DATA:
Download the reconstructed Manitoba annual precipitation and the Southeast Manitoba regional tree ring chronology from the WDC Paleo Archive.
Download Red River basin Q. macrocarpa ringwidth data used in this study:
Site Lat. ( N) Long. ( W) Type No. of Trees Span Elevation (m)
Hyland Park 49 59' 05" 97 02' 55" Living 17 1823 1999 230
Kildonan Park 49 56' 30" 97 06' 00" Living 38 1720 1999 230
Winnipeg 49 50' 97 12" Living 16 1822 1994 230
Winnipeg Historical 29 1644 1865
Barber House 49 54' 20" 97 07' 15" Historical 39 1648 1864
Munsen Park 49 52' 30" 97 09' 40" Living 9 1860 1999 230
Bruce Park 49 52' 30" 97 13' 30" Living 15 1855 1999 230
St. Vital Park 49 45' 25" 97 08' 50" Living 17 1855 1998 230
St. Norbert 49 45' 25" 97 08' 50" Living 10 1855 1998 230
LaBarriere Park 49 43' 10" 97 10' 30" Living 11 1892 1998 230
Delorme House 49 33' 40" 97 11' 05" Historical 3 1696 - 1853
Shay 49 38' 45" 97 06' 45" Living 14 1907 1999 230
Rat River House 49 35' 15" 97 08' 15" Historical 6 1659 - 1859
Ste. Agathe 49 32' 45" 97 12' 10" Living 11 1856 1998 230
Parker Farm 49 31' 50" 97 13' 00" Living 24 1877 1998 230
Horseshoe Lake 49 20' 25" 97 19' 30" Living 15 1907 1999 230
St. Jean Baptiste 49 16' 35" 97 19' 50" Living 10 1883 1997 235
Remus Farm 49 04' 20" 97 12' 30" Living 10 1875 1998 235
Marais River 49 03' 50" 97 18' 35" Living 13 1850 1998 235
Fort Dufferin 49 01' 50" 97 12' 10" Living 12 1866 1999 235
Fort Dufferin Historical 3 1723 - 1872
Assiniboine River alluvial logs Various locations Subfossil 37 1286 - 1968
Red River alluvial logs Various locations Subfossil 44 1448 - 1997

To read or view the full study, please visit the Ideal website.
It was published in Quaternary Research, Volume 58, pp. 103-111, September 2002.

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National Oceanic and Atmospheric Administration
13 September 2002