Results 1 - 10
of
32
Detecting climate effects on vegetation in northern mixed prairie using NOAA AVHRR 1-km time-series NDVI data. Remote Sens
"... Abstract: 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 ..."
Abstract
-
Cited by 6 (2 self)
- Add to MetaCart
(Show Context)
Abstract: 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.
The Future of Peary Caribou (Rangifer tarandus pearyi) in a Changing Climate
"... In the last half century, trends in mean temperature (increasing), snowfall (increasing), and snow cover (decreasing) that are consistent with global warming predictions have been observed in the Arctic (Brown and Alt 2001; Gitay et al. 2002; Whitfield et al. 2002). Additionally, climate variability ..."
Abstract
-
Cited by 4 (0 self)
- Add to MetaCart
(Show Context)
In the last half century, trends in mean temperature (increasing), snowfall (increasing), and snow cover (decreasing) that are consistent with global warming predictions have been observed in the Arctic (Brown and Alt 2001; Gitay et al. 2002; Whitfield et al. 2002). Additionally, climate variability in the Arctic has increased: there has been a significant increase in the number of thaw
Chapter 3—Weather and Climate
- In Compendium of Forest Hydrology and Geomorphology in British Columbia B.C; Ministry of Forests and Range, Research Branch, Victoria, B.C. and FORREX Forest Research Extension Partnership, Kamloops, BC: British
, 2008
"... This chapter introduces British Columbia’s weather and climate. “Weather ” refers to the specific condition of the atmosphere at a particular place and time. It is measured in terms of variables including ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
This chapter introduces British Columbia’s weather and climate. “Weather ” refers to the specific condition of the atmosphere at a particular place and time. It is measured in terms of variables including
Peatland hydrology of discontinuous permafrost in the Northwest Territories: overview and synthesis
- Canadian Journal of Water Resources
"... Abstract: Field studies were initiated in 1999 at Scotty Creek in the lower Liard River basin, NWT, Canada, to improve understanding of and ability to predict the major water fluxes and storage processes within a wetland-dominated zone of the discontinuous permafrost region. This paper synthesises a ..."
Abstract
-
Cited by 2 (1 self)
- Add to MetaCart
Abstract: Field studies were initiated in 1999 at Scotty Creek in the lower Liard River basin, NWT, Canada, to improve understanding of and ability to predict the major water fluxes and storage processes within a wetland-dominated zone of the discontinuous permafrost region. This paper synthesises a decade of published and unpublished research at Scotty Creek for the purpose of presenting the major factors that should be considered by water scientists and managers as a basis for modelling and management strategies. Five main topics are covered: (1) peatlands of lower Liard River valley; (2) hydrological characteristics of permafrost plateaus, flat bogs, and channel fens; (3) runoff generation on permafrost plateaus; (4) conceptual model of peatland hydrology; and (5) climate warming and implications for basin runoff. This synthesis offers a practical understanding of the hydrology of wetland-dominated basins with discontinuous permafrost. It also offers insight into how landscape changes resulting from climate or human disturbances may influence the basin hydrograph. Résumé: Des études sur le terrain ont été entamées en 1999 au ruisseau Scotty dans le cours inférieur du bassin de la rivière Liard (T.N.-O.), au Canada, afin d’améliorer la compréhension et la capacité de prédiction des flux d’eau majeurs et des processus d’emmagasinement dans une zone dominée par les milieux humides de la région du pergélisol discontinu. Le présent article résume une décennie de
Climatic Conditions in Northern Canada: Past and Future
"... This article reviews the historical, instrumental, and future changes in climate for the northern latitudes of Canada. Discussion of historical climate over the last 10 000 years focuses on major climatic shifts including the Medieval Warm Period and the Little Ice Age, and how these changes compare ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
(Show Context)
This article reviews the historical, instrumental, and future changes in climate for the northern latitudes of Canada. Discussion of historical climate over the last 10 000 years focuses on major climatic shifts including the Medieval Warm Period and the Little Ice Age, and how these changes compare with those most recently experienced during the period of instrumental records. In reference to the latter, details are noted about observed trends in temperature and precipitation that have been recorded over the last half century, which exhibit strong west to east and north to south spatial contrasts. A comprehen-sive review of future changes is also provided based on outputs from seven atmosphere–ocean global climate models and six emission scenarios. Discussion focuses on annual, seasonal, and related spatial changes for three 30-year periods centered on the 2020s, 2050s, and 2080s. In summary, substantial changes to temperature and precipitation are projected for the Canadian North during the twenty-first century. Although there is consid-erable variability within the various projections, all sce-narios show higher temperature and, for the most part, increasing precipitation over the entire region.
River-ice break-up/freeze-up: a review of climatic drivers, historical trends and future predictions
"... ABSTRACT. River ice plays a fundamental role in biological, chemical and physical processes that control freshwater regimes of the cold regions. Moreover, it can have enormous economic implications for river-based developments. All such activities and processes can be modified significantly by any c ..."
Abstract
-
Cited by 2 (0 self)
- Add to MetaCart
ABSTRACT. River ice plays a fundamental role in biological, chemical and physical processes that control freshwater regimes of the cold regions. Moreover, it can have enormous economic implications for river-based developments. All such activities and processes can be modified significantly by any changes to river-ice thickness, composition or event timing and severity. This paper briefly reviews some of the major hydraulic, mechanical and thermodynamic processes controlling river-ice events and how these are influenced by variations in climate. A regional and temporal synthesis is also made of the observed historical trends in river-ice break-up/freeze-up occurrence from the Eurasian and North American cold regions. This involves assessment of several hydroclimatic variables that have influenced past trends and variability in river-ice break-up/freeze-up dates including air-temperature indicators (e.g. seasonal temperature, 08C isotherm dates and various degree-days) and large-scale atmospheric circulation patterns or teleconnections. Implications of future climate change on the timing and severity of river-ice events are presented and discussed in relation to the historical trends. Attention is drawn to the increasing trends towards the occurrence of mid-winter break-up events that can produce especially severe flood conditions but prove to be the most difficult type of event to model and predict.
AUTHORS
, 2003
"... discussion and suggestions in the initial stages of this research project. We would also like to thank Ken Fletcher, John Morris and Nick Treadgold from Statistics New Zealand for invaluable discussions and the provision of data. We are grateful to Nargis ..."
Abstract
-
Cited by 1 (0 self)
- Add to MetaCart
discussion and suggestions in the initial stages of this research project. We would also like to thank Ken Fletcher, John Morris and Nick Treadgold from Statistics New Zealand for invaluable discussions and the provision of data. We are grateful to Nargis
The Mann-Kendall test: the need to consider the interaction between serial correlation and trend
"... ABSTRACT. Pre-whitening approaches have been widely used to remove the influence of serial correlations on the Mann-Kendall trend test (MK_prew). However, previous studies indicate that this procedure may lead to a false reduction of the significance of a trend. An alternative approach (MK_interact) ..."
Abstract
-
Cited by 1 (1 self)
- Add to MetaCart
ABSTRACT. Pre-whitening approaches have been widely used to remove the influence of serial correlations on the Mann-Kendall trend test (MK_prew). However, previous studies indicate that this procedure may lead to a false reduction of the significance of a trend. An alternative approach (MK_interact) has been proposed to improve the assessment of the significance of a trend in auto-correlated data. Therefore, the present study compared the performance of the MK_prew and MK_interact for detecting trends in auto-correlated series. Sets of Monte Carlo experiments were carried out to evaluate the occurrence of type I and II errors obtained from both approaches. The analyses were also based on 10-day values of the difference between precipitation and potential evapotranspiration (P-EP) obtained from the location of Campinas, State of São Paulo, Brazil. The results found in this study allow us to conclude that the MK_interac outperformed the MK_prew in correctly identifying the significance of trends and that, concerning agricultural interests, the decreasing trend described by the MK_interac during the beginning of the crop growing seasons may reveal an unfavorable temporal distribution of the P-EP values.
Future changes in intense precipitation over Canada assessed from multi-model NARCCAP ensemble simulations
, 2012
"... ABSTRACT: Annual maxima (AM) series of precipitation from 15 simulations of the North American Regional Climate Change Assessment Program (NARCCAP) have been analysed for gridpoints covering Canada and the northern part of United States. The NARCCAP Regional Climate Models' simulations have be ..."
Abstract
- Add to MetaCart
(Show Context)
ABSTRACT: Annual maxima (AM) series of precipitation from 15 simulations of the North American Regional Climate Change Assessment Program (NARCCAP) have been analysed for gridpoints covering Canada and the northern part of United States. The NARCCAP Regional Climate Models' simulations have been classified into the following three groups based on the driving data used at the RCMs boundaries: (1) NCEP (6 simulations); (2) GCM-historical (5 simulations); and (3) GCM-future (4 simulations). Historical simulations are representative of the 1968-2000 period while future simulations cover the 2041-2070 period. A reference common grid has been defined to ease the comparison. Multi-model average intensities of AM precipitation of 6-, 12-, 24-, 72-, and 120-h for 2-, 5-, 10-, and 20-year return periods have been estimated for each simulation group. Comparison of results from NCEP and GCM-historical groups shows good overall agreement in terms of spatial distribution of AM intensities. Comparison of GCM-future and GCM-historical groups clearly shows widespread increases with median relative changes across all gridpoints ranging from 12 to 18% depending on durations and return periods. Fourteen Canadian climatic regions have been used to define regional projections and average regional changes in intense precipitation have been estimated for each duration and return period. Uncertainties on these regional values, resulting from inter-model variability, were also estimated. Results suggest that inland regions (e.g. Ontario and more specifically Southern Ontario, the Prairies, Southern Quebec) will experience the largest relative increases in AM intensities while coastal regions (e.g. Atlantic Provinces and the West Coast) will experience the smallest ones. These projections are most valuable inputs for the assessment of future impact of climate change on water infrastructures and the development of more efficient adaptation strategies.
Temporal and Spatial Changes of the Agroclimate in Alberta, Canada, from 1901 to 2002
"... ABSTRACT This paper analyzes the long-term temporal trends in the agroclimate of Alberta, Canada, and explores the spatial variations of the agroclimatic resources and the potential crop-growing area in Alberta. Nine agroclimatic parameters are investigated: May-August precipitation (PCPN), the st ..."
Abstract
- Add to MetaCart
ABSTRACT This paper analyzes the long-term temporal trends in the agroclimate of Alberta, Canada, and explores the spatial variations of the agroclimatic resources and the potential crop-growing area in Alberta. Nine agroclimatic parameters are investigated: May-August precipitation (PCPN), the start of growing season (SGS), the end of the growing season (EGS), the length of the growing season (LGS), the date of the last spring frost (LSF), the date of the first fall frost (FFF), the length of the frost-free period (FFP), growing degree-days (GDDs), and corn heat units (CHUs). The temporal trends in the agroclimatic parameters are analyzed by using linear regression. The significance tests of the trends are made by using Kendall's tau method. The results support the following conclusions. 1) The Alberta PCPN has increased 14% from 1901 to 2002, and the increment is the largest in the north and the northwest of Alberta, then diminishes (or even becomes negative over two small areas) in central and southern Alberta, and finally becomes large again in the southeast corner of the province. 2) No significant long-term trends are found for the SGS, EGS, and LGS. 3) An earlier LSF, a later FFF, and a longer FFP are obvious all over the province. 4) The area with sufficient CHU for corn production, calculated according to the 1973-2002 normal, has extended to the north by about 200-300 km, when compared with the 1913-32 normal, and by about 50-100 km, when compared with the 1943-72 normal; this expansion implies that the potential exists to grow crops and raise livestock in more regions of Alberta than was possible in the past. The annual total precipitation follows a similar increasing trend to that of the May-August precipitation, and the percentile analysis of precipitation attributes the increase to low-intensity events. The changes of the agroclimatic parameters imply that Alberta agriculture has benefited from the last century's climate change.
