In:
Hydrology and Earth System Sciences, Copernicus GmbH, Vol. 25, No. 5 ( 2021-05-18), p. 2513-2541
Abstract:
Abstract. East of the Continental Divide in the cold interior of Western Canada, the Mackenzie and Nelson River basins have some of the world's most extreme and
variable climates, and the warming climate is changing the landscape, vegetation, cryosphere, and hydrology. Available data consist of streamflow
records from a large number (395) of natural (unmanaged) gauged basins,
where flow may be perennial or temporary, collected either year-round or
during only the warm season, for a different series of years between 1910
and 2012. An annual warm-season time window where observations were available across all stations was used to classify (1) streamflow regime and (2) seasonal trend patterns. Streamflow trends were compared to changes
in satellite Normalized Difference Indices. Clustering using dynamic time warping, which overcomes differences in streamflow timing due to latitude or elevation, identified 12 regime
types. Streamflow regime types exhibit a strong connection to location; there is a strong distinction between mountains and plains and associated with ecozones. Clustering of seasonal trends resulted in six trend patterns that also follow a distinct spatial organization. The trend patterns include one with decreasing streamflow, four with different patterns of increasing streamflow, and one without structure. The spatial patterns of
trends in mean, minimum, and maximum of Normalized
Difference Indices of water and snow (NDWI and NDSI) were similar to each
other but different from Normalized
Difference Index of vegetation (NDVI) trends. Regime types, trend patterns, and satellite indices trends each showed spatially coherent patterns separating the Canadian Rockies and other mountain ranges in the west from the poorly
defined drainage basins in the east and north. Three specific areas of
change were identified: (i) in the mountains and cold taiga-covered
subarctic, streamflow and greenness were increasing while wetness and
snowcover were decreasing, (ii) in the forested Boreal Plains, particularly in the mountainous west, streamflows and greenness were decreasing but wetness and snowcover were not changing, and (iii) in the semi-arid to sub-humid agricultural Prairies, three patterns of increasing streamflow and an
increase in the wetness index were observed. The largest changes in
streamflow occurred in the eastern Canadian Prairies.
Type of Medium:
Online Resource
ISSN:
1607-7938
DOI:
10.5194/hess-25-2513-2021
DOI:
10.5194/hess-25-2513-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2100610-6
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