Precipitation Trends on the Canadian Prairies*

Akinremi, O. O.; McGinn, S. M.; Cutforth, H. W.

doi:10.1175/1520-0442(1999)012<2996:ptotcp>2.0.co;2

Cited by 116 publications

(92 citation statements)

References 10 publications

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“…The increased mean temperature during the growing season is consistent with the fact that annual mean temperature increased from 1900 to 1998 in southern Canada [51]. The increasing trend of precipitation is consistent with the finding of [52,53] that precipitation in Canadian prairies has increased. The increasing trend of annual NDVI can be accounted for by the increased temperature and precipitation.…”

Section: Trends Of Ndvi Temperature and Precipitationsupporting

confidence: 86%

Detecting Climate Effects on Vegetation in Northern Mixed Prairie Using NOAA AVHRR 1-km Time-Series NDVI Data

Guo

2012

Remote Sensing

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Grasslands hold varied grazing capacity, provide multiple habitats for diverse wildlife, and are a key component of carbon stock. Research has indicated that grasslands are experiencing effects related to recent climate trends. Understanding how grasslands respond to climate variation thus is essential. However, it is difficult to separate the effects of climate variation from grazing. This study aims to document vegetation condition under climate variation in Grasslands National Park (GNP) of Canada, a grassland ecosystem without grazing for over 20 years, using Normalized Difference Vegetation Index (NDVI) data to establish vegetation baselines. The main findings are (1) precipitation has more effects than temperature on vegetation; (2) the growing season of vegetation had an expanding trend indicated by earlier green-up and later senescence; (3) phenologically-tuned annual NDVI had an increasing trend from 1985 to 2007; and (4) the baselines of annual NDVI range from 0.13 to 0.32, and only the NDVI in 1999 is beyond the upper bound of the baseline. Our results indicate that vegetation phenology and condition have slightly changed in GNP since 1985, although vegetation condition in most years was still within the baselines.

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Section: Trends Of Ndvi Temperature and Precipitationsupporting

confidence: 86%

Detecting Climate Effects on Vegetation in Northern Mixed Prairie Using NOAA AVHRR 1-km Time-Series NDVI Data

Guo

2012

Remote Sensing

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“…3), the hydrological balance of these prairie lakes was maintained by inflow of water (Fig. 5a), either from groundwater (van der Fritz et al 2000;Yu et al 2002) or from usually high supply of runoff from catchments, most of which is derived from winter precipitation (Steppuhn 1981;Akinremi et al 1999). These findings are consistent with the observation that permanent lakes are common on the northern Great Plains (Last 1992) despite precipitation deficits that exceed 40 cm yr 21 (Fig.…”

Section: Discussionsupporting

confidence: 75%

“…Implications for climate-lake relationships-Our analyses suggest that winter precipitation is the main control of hydrologic variability in lakes of the northern Great Plains, either directly due to its predominant contribution to surface runoff (Steppuhn 1981;Akinremi et al 1999), or indirectly via replenishment of groundwater aquifers Birks and Remenda 1999;Yu et al 2002). Consequently, changes in climate systems that regulate the supply, persistence, or melting of snow are predicted to have the strongest effects on prairie lake chemistry and sustainability.…”

Section: Discussionmentioning

confidence: 86%

Spatial and temporal variability of prairie lake hydrology as revealed using stable isotopes of hydrogen and oxygen

et al. 2009

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Evaporation and groundwater fluxes are thought to regulate hydrologic variability in lakes of the northern Great Plains, but little is known of how the relative importance of these processes may vary in time or space. To address this issue, we measured the isotopic composition of water (d 18 O, d 2 H) from 70 closed-basin lakes in southern Saskatchewan, Canada. All lakes occupied endorheic basins along a long gradient of salinity (0.2-115 g total dissolved solids L 21 ). Lakes exhibited synchronous seasonal changes in salinity (synchrony, S 5 0.78) and d 18 O (S 5 0.84) during the dry summer of 2003 (,195 mm rain), whereas coherence was reduced to 0.56 and 0.22, respectively, during the wet summer of 2004 (,295 mm rain). However, despite evaporative enrichment of isotopic ratios during dry summers, hydrologic balances were regulated mainly by changes in water inflow (I) rather than evaporation (E) in both wet and dry years, with particularly strong influence of inflow (lowest E : I ratio) in dry southwestern regions. Analysis of isotopic composition also identified winter precipitation or groundwater as the most influential source of water to most lakes, despite only ,30% of annual precipitation being delivered during winter. Therefore, although seasonal variability in lake chemistry was influenced by evaporation during summer, long-term mean chemical characteristics of prairie lakes were regulated mainly by changes in winter precipitation or groundwater influx.Lakes are abundant in the northern Great Plains (Last 1992) despite intense evaporation (Pham et al. 2008) and net precipitation deficits of 40 cm yr 21 to 60 cm yr 21 (Laird et al. 1996). In general, inter-annual variability of meteorological conditions that affect the persistence of lakes (temperature, seasonal precipitation) is regulated by the interplay between air masses arising over the Arctic, Pacific Ocean, and Gulf of Mexico (Bryson and Hare 1974), as well as global atmosphere-ocean systems such as the El Niñ o-Southern Oscillation (ENSO; Trenberth and Hurrell 1994), North Atlantic Oscillation (NAO; Hurrell 1995), and the Pacific Decadal Oscillation (PDO; Mantua et al. 1997). In addition, at a regional scale, the spatial and temporal variability of prairie lake hydrology is also affected by groundwater fluxes (van der Fritz et al. 2000) and by an unusually high supply of runoff from large catchments, most of which is derived from winter precipitation (Steppuhn 1981;Akinremi et al. 1999). However, despite these generalities, little is known of the specific conditions under which evaporation or water influx may control changes in lake chemistry and persistence, nor of the relative importance of summer and winter precipitation in the hydrologic budget of local and regional lakes. Consequently, an improved understanding of the basic hydrology of prairie lakes is needed to both forecast the effects of future climate change on lakes of the northern Great Plains, and to better interpret paleolimnological records of past climate variability in th...

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“…These observations are not surprising given that there exists an increasing trend in mean June-July moisture conditions during the study period ( Figure 2). A similar trend has also been shown by Akinremi and McGinn (1999). Overall, anomalously dry conditions were present in at least one crop district during 62 years (77.5% of the growing seasons).…”

Section: Severity and Spatial Extentsupporting

confidence: 84%

Characterizing the spatial and temporal variability of June–July moisture conditions in the Canadian prairies

Quiring

Papakyriakou

2005

Intl Journal of Climatology

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Palmer's moisture anomaly index (Z-index) was used to characterize the frequency, severity, and spatial extent of June-July moisture anomalies for 43 crop districts across the Canadian prairies during 1920-99. In addition, the main modes of spatial and temporal variability in moisture conditions were identified and used to elucidate the physical mechanisms responsible for causing these moisture anomalies to occur. The crop districts were divided into five relatively homogeneous moisture regions using cluster analysis, and moisture anomaly statistics were analysed for each region.The single most severe June-July drought on the Canadian prairies occurred in 1961. This drought covered more than 86% of the study region and had a mean severity (Z-index) of −5.67. Other severe June-July droughts occurred in the Canadian prairies (in order of severity) in 1988, 1936, 1929, and 1937. The results demonstrated that the severity and spatial extent of moisture anomalies on the Canadian prairies are strongly correlated, indicating that the more severe events tend to affect larger areas. The most drought-prone regions experienced moisture conditions detrimental to crop production in approximately one year out of every six years.The spatial analysis revealed the existence of three preferred spatial patterns of moisture variability on the Canadian prairies and each pattern can be attributed to a unique set of atmospheric and oceanic forcings. The temporal analysis verified the presence of coherent periodicities (in particular quasi-2, -4, and -10-15 year oscillations) in the moisture time series.

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Precipitation Trends on the Canadian Prairies*

Cited by 116 publications

References 10 publications

Detecting Climate Effects on Vegetation in Northern Mixed Prairie Using NOAA AVHRR 1-km Time-Series NDVI Data

Detecting Climate Effects on Vegetation in Northern Mixed Prairie Using NOAA AVHRR 1-km Time-Series NDVI Data

Spatial and temporal variability of prairie lake hydrology as revealed using stable isotopes of hydrogen and oxygen

Characterizing the spatial and temporal variability of June–July moisture conditions in the Canadian prairies

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