Modeling the Impact of Climate Change on Runoff and Annual Water Balance of an Arctic Headwater Basin

Climate change will be an important issue facing Arctic areas in the coming decades since climate models are projecting warmer and wetter conditions for many northern regions. From a hydrological perspective, critical issues include a shortened snow cover season, changes in winter snow cover properties, and changes in the timing and volume of snowmelt runoff. To assess the impacts of projected temperature and precipitation changes on the hydrology of a small Arctic headwater basin, the distributed hydrological model WATFLOOD was used in conjunction with selected Global Circulation Models (GCMs) and future climate scenarios. It was found that the hydrological model simulated basin runoff adequately either with input climate data collected in the study area or with input data from a long-term climate station located approximately 50 km south. WATFLOOD was then used to predict future runoff using GCM outputs for the 2040–69 and 2070–99 time periods. The results gave dates of first and peak runoff that were, on average, up to 25 days earlier than in current (1961–90) climate. In addition, future runoff and evaporation volumes increased by up to 48% as a result of projected increases in temperature and precipitation. Furthermore, a large number of simulated years showed midwinter melt periods, which will have major impacts on snowpack properties and, in turn, on human, animal, and plant life in this region.Au cours des décennies à venir, puisque les modèles climatiques projettent des conditions plus chaudes et plus humides pour de nombreuses régions nordiques, les régions arctiques feront face à l’important enjeu du changement climatique. Du point de vue hydrologique, les enjeux critiques se traduisent par une saison de couverture de neige plus courte, par des changements du point de vue des propriétés de la couverture de neige hivernale ainsi que par des changements par rapport au moment et au volume d’écoulement de la fonte des neiges. Nous avons utilisé le modèle hydrologique distribué WATFLOOD, certains modèles de circulation globale et des scénarios climatiques futurs pour évaluer les incidences des changements projetés en matière de températures et de précipitations sur l’hydrologie d’un petit bassin d’amont de l’Arctique. Le modèle hydrologique a permis de simuler, de manière adéquate, l’écoulement du bassin soit grâce à l’introduction des données climatiques recueillies dans la région visée par l’étude, soit grâce aux données à long terme provenant d’une station climatique située à une cinquantaine de kilomètres au sud. Ensuite, WATFLOOD a permis de prédire l’écoulement futur en recourant au débit des modèles de circulation globale pour les périodes allant de 2040 à 2069 et de 2070 à 2099. D’après les résultats obtenus, les dates du premier écoulement et de l’écoulement de pointe seraient devancées de jusqu’à 25 jours par rapport au climat actuel (période de 1961 à 1990). De plus, les volumes d’écoulement et d’évaporation futurs connaissaient une augmentation atteignant jusqu’à 48 % en raison des élévations prévues de températures et de précipitations. De plus, un grand nombre d’années simulées a permis de constater des périodes de fonte en plein milieu de l’hiver, ce qui aura une grande incidence sur les propriétés de la couverture de neige et, par conséquent, sur les êtres humains, les animaux et la vie végétale dans cette région

The effect of magnetic dipolar interactions on the interchain spin wave dispersion in CsNiF_3

Inelastic neutron scattering measurements were performed on the ferromagnetic chain system CsNiF_3 in the collinear antiferromagnetic ordered state below T_N = 2.67K. The measured spin wave dispersion was found to be in good agreement with linear spin wave theory including dipolar interactions. The additional dipole tensor in the Hamiltonian was essential to explain some striking phenomena in the measured spin wave spectrum: a peculiar feature of the dispersion relation is a jump at the zone center, caused by strong dipolar interactions in this system. The interchain exchange coupling constant and the planar anisotropy energy were determined within the present model to be J'/k_B = -0.0247(12)K and A/k_B = 3.3(1)K. This gives a ratio J/J' \approx 500, using the previously determined intrachain coupling constant J/k_B = 11.8$. The small exchange energy J' is of the same order as the dipolar energy, which implies a strong competition between the both interactions.Comment: 18 pages, TeX type, 7 Postscript figures included. To be published in Phys. Rev.

Influence of climatic variables on crown condition in pine forests of Northern Spain

Producción CientíficaThe aim of this study was to find relationships between crown condition and some climatic parameters to identify which are those having a main influence on crown condition, and how this influence is shown in the tree (crown transparency), and to contribute to the understanding of how these parameters will affect under future climate change scenarios

Limitations of Water Resources Infrastructure for Reducing Community Vulnerabilities to Extremes and Uncertainty of Flood and Drought

Debate and deliberation surrounding climate change has shifted from mitigation toward adaptation, with much of the adaptation focus centered on adaptive practices, and infrastructure development. However, there is little research assessing expected impacts, potential benefits, and design challenges that exist for reducing vulnerability to expected climate impacts. The uncertainty of design requirements and associated government policies, and social structures that reflect observed and projected changes in the intensity, duration, and frequency of water-related climate events leaves communities vulnerable to the negative impacts of potential flood and drought. The results of international research into how agricultural infrastructure features in current and planned adaptive capacity of rural communities in Argentina, Canada, and Colombia indicate that extreme hydroclimatic events, as well as climate variability and unpredictability are important for understanding and responding to community vulnerability. The research outcomes clearly identify the need to deliberately plan, coordinate, and implement infrastructures that support community resiliency.Fil: McMartin, Dena W.. University of Regina; CanadáFil: Hernani Merino, Bruno H.. University of Regina; CanadáFil: Bonsal, Barrie. Environment Canada; CanadáFil: Hurlbert, Margot. University of Regina; CanadáFil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Cientifícas y Tecnológicas; ArgentinaFil: Ocampo, Olga L.. Universidad Autónoma de Manizales; ColombiaFil: Upegui, Jorge Julián Vélez. Universidad Nacional de Colombia; ColombiaFil: Poveda, Germán. Universidad Nacional de Colombia; ColombiaFil: Sauchyn, David J.. University of Regina; Canad

Historical drought patterns over Canada and their teleconnections with large-scale climate signals

Drought is a recurring extreme climate event and among the most costly natural disasters in the world. This is particularly true over Canada, where drought is both a frequent and damaging phenomenon with impacts on regional water resources, agriculture, industry, aquatic ecosystems, and health. However, nationwide drought assessments are currently lacking and impacted by limited ground-based observations. This study provides a comprehensive analysis of historical droughts over the whole of Canada, including the role of large-scale teleconnections. Drought events are characterized by the Standardized Precipitation Evapotranspiration Index (SPEI) over various temporal scales (1, 3, 6, and 12 consecutive months, 6 months from April to September, and 12 months from October to September) applied to different gridded monthly data sets for the period 1950–2013. The Mann–Kendall test, rotated empirical orthogonal function, continuous wavelet transform, and wavelet coherence analyses are used, respectively, to investigate the trend, spatio-temporal patterns, periodicity, and teleconnectivity of drought events. Results indicate that southern (northern) parts of the country experienced significant trends towards drier (wetter) conditions although substantial variability exists. Two spatially well-defined regions with different temporal evolution of droughts were identified – the Canadian Prairies and northern central Canada. The analyses also revealed the presence of a dominant periodicity of between 8 and 32 months in the Prairie region and between 8 and 40 months in the northern central region. These cycles of low-frequency variability are found to be associated principally with the Pacific–North American (PNA) and Multivariate El Niño/Southern Oscillation Index (MEI) relative to other considered large-scale climate indices. This study is the first of its kind to identify dominant periodicities in drought variability over the whole of Canada in terms of when the drought events occur, their duration, and how often they occur

Inter-comparison of daily precipitation products for large-scale hydro-climatic applications over Canada

A number of global and regional gridded climate products based on multiple data sources are available that can potentially provide reliable estimates of precipitation for climate and hydrological studies. However, research into the consistency of these products for various regions has been limited and in many cases non-existent. This study inter-compares several gridded precipitation products over 15 terrestrial ecozones in Canada for different seasons. The spatial and temporal variability of the errors (relative to station observations) was quantified over the period of 1979 to 2012 at a 0.5° and daily spatio-temporal resolution. These datasets were assessed in their ability to represent the daily variability of precipitation amounts by four performance measures: percentage of bias, root mean square error, correlation coefficient, and standard deviation ratio. Results showed that most of the datasets were relatively skilful in central Canada. However, they tended to overestimate precipitation amounts in the west and underestimate in the north and east, with the underestimation being particularly dominant in northern Canada (above 60°N). The global product by WATCH Forcing Data ERA-Interim (WFDEI) augmented by Global Precipitation Climatology Centre (GPCC) data (WFDEI [GPCC]) performed best with respect to different metrics. The Canadian Precipitation Analysis (CaPA) product performed comparably with WFDEI [GPCC]; however, it only provides data starting in 2002. All the datasets performed best in summer, followed by autumn, spring, and winter in order of decreasing quality. Findings from this study can provide guidance to potential users regarding the performance of different precipitation products for a range of geographical regions and time periods