Abstract Interfaces for Data Analysis: Component Architecture for Data Analysis Tools

The fast turnover of software technologies, in particular in the domain of interactivity (covering user interface and visualisation), makes it difficult for a small group of people to produce complete and polished software-tools before the underlying technologies make them obsolete. At the HepVis '99 workshop, a working group has been formed to improve the production of software tools for data analysis in HENP. Beside promoting a distributed development organisation, one goal of the group is to systematically design a set of abstract interfaces based on using modern OO analysis and OO design techniques. An initial domain analysis has come up with several categories (components) found in typical data analysis tools: Histograms, Ntuples, Functions, Vectors, Fitter, Plotter, Analyzer and Controller. Special emphasis was put on reducing the couplings between the categories to a minimum, thus optimising re-use and maintainability of any component individually. The interfaces have been defined in Java and C++ and implementations exist in the form of libraries and tools using C++ (Anaphe/Lizard, OpenScientist) and Java (Java Analysis Studio). A special implementation aims at accessing the Java libraries (through their Abstract Interfaces) from C++. This paper gives an overview of the architecture and design of the various components for data analysis as discussed in AIDA

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr⁻¹) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr−1) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance

An inventory and topographic analysis of glaciers in the Torngat Mountains, northern Labrador, Canada

AbstractThis study presents the first complete glacier inventory of the Torngat Mountains, northern Labrador, Canada. In total, 195 glaciers and ice masses are identified, covering a total area of 24.5 ± 1.8 km2. Mapped ice masses range in size from 0.01 to 1.26 km2, with a median size of 0.08 km2. Ice masses have a median elevation of 776 m a.s.l. and span an altitudinal range of 290–1500 m a.s.l. Indications of ice flow suggest at least 105 active glaciers in the Torngat Mountains. Analysis of morphometric and topographic parameters suggests that the regional distribution of ice masses is linked to physiographic setting while the preservation of coastal ice masses at low elevation is related to local meteorological conditions. In the most coastal environments, ice masses are shown to exist below the regional glaciation level due to topographic shadowing, coastal proximity and widespread debris cover. This study provides a baseline for future change assessment.</jats:p

Trends in Antarctic Peninsula surface melting conditions from observations and regional climate modeling

Multidecadal meteorological station records and microwave backscatter time-series from the SeaWinds scatterometer onboard QuikSCAT (QSCAT) were used to calculate temporal and spatial trends in surface melting conditions on the Antarctic Peninsula (AP). Four of six long-term station records showed strongly positive and statistically significant trends in duration of melting conditions, including a 95% increase in the average annual positive degree day sum (PDD) at Faraday/Vernadsky, since 1948. A validated, threshold-based melt detection method was employed to derive detailed melt season onset, extent, and duration climatologies on the AP from enhanced resolution QSCAT data during 1999–2009. Austral summer melt on the AP was linked to regional- and synoptic-scale atmospheric variability by respectively correlating melt season onset and extent with November near-surface air temperatures and the October–January averaged index of the Southern Hemisphere Annular Mode (SAM). The spatial pattern, magnitude, and interannual variability of AP melt from observations was closely reproduced by simulations of the regional model RACMO2. Local discrepancies between observations and model simulations were likely a result of the QSCAT response to, and RACMO2 treatment of, ponded surface water, and the relatively crude representation of coastal climate in the 27 km RACMO2 grid

Future evolution and uncertainty of river flow regime change in a deglaciating river basin

The flow regimes of glacier-fed rivers are sensitive to climate change due to strong climate–cryosphere–hydrosphere interactions. Previous modelling studies have projected changes in annual and seasonal flow magnitude but neglect other changes in river flow regime that also have socio-economic and environmental impacts. This study employs a signature-based analysis of climate change impacts on the river flow regime for the deglaciating Virkisá river basin in southern Iceland. Twenty-five metrics (signatures) are derived from 21st century projections of river flow time series to evaluate changes in different characteristics (magnitude, timing and variability) of river flow regime over sub-daily to decadal timescales. The projections are produced by a model chain that links numerical models of climate and glacio-hydrology. Five components of the model chain are perturbed to represent their uncertainty including the emission scenario, numerical climate model, downscaling procedure, snow/ice melt model and runoff-routing model. The results show that the magnitude, timing and variability of glacier-fed river flows over a range of timescales will change in response to climate change. For most signatures there is high confidence in the direction of change, but the magnitude is uncertain. A decomposition of the projection uncertainties using analysis of variance (ANOVA) shows that all five perturbed model chain components contribute to projection uncertainty, but their relative contributions vary across the signatures of river flow. For example, the numerical climate model is the dominant source of uncertainty for projections of high-magnitude, quick-release flows, while the runoff-routing model is most important for signatures related to low-magnitude, slow-release flows. The emission scenario dominates mean monthly flow projection uncertainty, but during the transition from the cold to melt season (April and May) the snow/ice melt model contributes up to 23&thinsp;% of projection uncertainty. Signature-based decompositions of projection uncertainty can be used to better design impact studies to provide more robust projections.</p