Base de données de recherche des TNO

étiquettes: physical sciences, limnology, ocean physics, delta lakes, biogeochemistry, hydrological evolution

Objectif(s): The goals of this research are to examine: 1) measurements of water depths and lake depths for selected area of the Mackenzie Delta; 2) changes in lake flooding and historical lake boundaries in the Mackenzie Delta.

Description du projet: The goals of this research are to examine: 1) measurements of water depths and lake depths for selected area of the Mackenzie Delta; 2) changes in lake flooding and historical lake boundaries in the Mackenzie Delta. Specific activities for this field season include the following: (1) Improved information on the detailed topography of the Mackenzie Delta floodplain and how delta water levels and nutrients in the waters are affected by the topography represents new work being launched this year. This information is needed to address an important knowledge gap and complement an International Polar Year investigation on channel network water levels in the delta (IPY-SCARF), via developing ability to model how changing low- and high-water levels will quantitatively affect the area and water volume of off-channel aquatic habitat in the Mackenzie Delta, including the Kendall Island Bird Sanctuary of the outer delta. Recent prior work shows that over the past 30+ years, summer low-water levels in the delta may have increased by an amount (0.3 m) equivalent to three times local sea level rise (0.1 m) over the same period. Such amplification of recent sea level rise has been unexpected and may be a result of enhanced storm surges in response to receding arctic sea ice or coastal backwater effects on the river flow. Other work suggests a recent decline in river-ice breakup effects in the delta that historically have been an important control on annual peak water levels. (2) Assessing changes in lake flooding and historical lake boundaries in the Mackenzie Delta. Important information needed to assess how long-term changes in water levels will affect the delta is the ability to estimate potential effects in years where water levels are higher, or lower, than what has been observed in the limited 30 year record, and assessing whether observations from 50 years ago are still valid. Developing such capability requires expanding the information presently available on areal extent and depth of annual flooding during breakup of the delta. Prior information on lake flooding regimes, plus recent map-based census of delta lakes, are based on topographic maps derived from 1950's aerial photography. GIS analysis will compare 2008 aerial photos and satellite imagery against the 1950's maps of the delta. Field work will involve investigating specific areas of the delta where changes are evident (e.g. lake disappearance or appearance of new lakes). The field work will be based from the Aurora Research Institute and will consist of accessing a number of lakes via helicopter during late July or early August to make GPS survey measurements of lake-shore shapes, measure water depths, and take aerial photography of specific lakes of interest. Field work will be based on four areas where the researchers have worked extensively in the past. Research is posted on the Mackenzie Delta research at http://www.sfu.ca/limnology. This highlights the research and student opportunities for training in arctic-based research. The fieldwork for this study will be conducted at 4 clusters of lake in the Delta Region a) Opposite to the Inuvik Town Site; 2) North of Inuvik (East Channel); 3) North-East Point Separation; 4) Close to Williams Island from May 1 to August 27, 2010. Please contact the researcher for specific research locations.