Evolution of Melt Pond Volume on the Surface of the Greenland Ice Sheet

The presence of surface meltwater on ice caps and ice sheets is an important glaciological and climatological characteristic. We describe an algorithm for estimating the depth and hence volume of surface melt ponds using multispectral ASTER satellite imagery. The method relies on reasonable assumptions about the albedo of the bottom surface of the ponds and the optical attenuation characteristics of the ponded meltwater. We apply the technique to sequences of satellite imagery acquired over the western margin of the Greenland Ice Sheet to derive changes in melt pond extent and volume during the period 2001 - 2004. Results show large intra- and interannual changes in ponded water volumes, and large volumes of liquid water stored in extensive slush zones

A 200 Year Sub-Annual Record of Sulfate in West Antarctica, from Sixteen Ice Cores

Sixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO42- and excess (xs) SO42- is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000m. Our XsSO(4)(2-) records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO42- concentrations but do reveal that a major climate transition takes place over West Antarctica at similar to 1940. Global-scale volcanic eruptions appear as significant peaks in the robust-spline residual xsSO(4)(2-) records from sites located above 1000 m elevation but do not appear in the residual records from sites located below 1000 m

The education crisis : business and government's role in reform

Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1989.Includes bibliographical references (leaves 157-159).by Carleton S. Fiorina.M.S

Subject-oriented plural method meets BPMN: a case study

Subject-oriented approach to business process management focuses on the subjects and their interactions with the aim to capture more accurate process information with increased fidelity. In a common setting, business processes are modeled by process engineers or modeling experts who often create their processes in a top-down fashion. However, this may pose risks to the acceptance and adoption of these models in practice, particularly in knowledge-centric environments. The Plural method follows a subject-oriented approach and allows process participants, rather than a centralized group of process engineers, to model and maintain their processes in a decentralized way. It guides process participants to focus on the roles and their interactions in terms of message exchanges. This study investigates the use of BPMN 2.0 for the Plural method. With the aim to show the applicability of the notation for a subject-oriented approach and report on the benefits and limitations of the new edition of the Plural method in general, we performed a case study in an industry company. Guided by a coordinator, 11 process participants modeled four processes that they participate by following the Plural method. These models were also compared with the classical models developed prior to the application of the Plural method to better understand the influence. Analyses showed that the application of the Plural resulted in more complete process models. However, there are concerns regarding the understandability of these models when compared with their classical counterparts. It has been shown that the Plural method is a powerful tool for process discovery and modeling, but an improvement on its models is needed to obtain full value of the framework

Atmospheric Soluble Dust Records From a Tibetan Ice Core: Possible Climate Proxies and Teleconnection with the Pacific Decadal Oscillation

In autumn 2005, a joint expedition between the University of Maine and the Institute of Tibetan Plateau Research recovered three ice cores from Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m above sea level) on the northern side of Mt. Geladaindong, central Tibetan Plateau. Isotopes (δ18O), major soluble ions (Na+, K+, Mg2+, Ca2+, Cl−, NO3−, SO42−), and radionuclide (β‐activity) measurements from one of the cores revealed a 70‐year record (1935–2005). Statistical analysis of major ion time series suggests that atmospheric soluble dust species dominate the chemical signature and that background dust levels conceal marine ion species deposition. The soluble dust time series have interspecies relations and common structure (empirical orthogonal function (EOF) 1), suggesting a similar soluble dust source or transport route. Annual and seasonal correlations between the EOF 1 time series and National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis climate variables (1948–2004) suggest that the Mt. Geladaindong ice core record provides a proxy for local and regional surface pressure. An approximately threefold decrease of soluble dust concentrations in the middle to late 1970s, accompanied by regional increases in pressure and temperature and decreases in wind velocity, coincides with the major 1976–1977 shift of the Pacific Decadal Oscillation (PDO) from a negative to a positive state. This is the first ice core evidence of a potential teleconnection between central Asian atmospheric soluble dust loading and the PDO. Analysis of temporally longer ice cores from Mt. Geladaindong may enhance understanding of the relationship between the PDO and central Asian atmospheric circulation and subsequent atmospheric soluble dust loading

Die Evolution einer Standardarchitektur für Betriebliche Informationssysteme

Echterhoff D, Grasmugg S, Mersch S, Mönckemeyer M, Spitta T, Wrede S. Die Evolution einer Standardarchitektur für Betriebliche Informationssysteme. In: Spitta T, Borchers J, Sneed HM, eds. Software-Management 2002. LNI. Vol P-23. Bonn: GI e.V.; 2002: 131-142.The paper outlines the history of a standard architecture for small and medium sized administrative systems. It has been developped 1985 in the Schering AG / Berlin, and applied in several firms over more than 15 years. Some of the about 150 applications, developped and maintained by more than 100 programmers, are still in operation. In 1999 a revision of the architecture and a new implementation in Java was started. The latest version is a four-level-architecture for distributed systems with a browser as user interface. Aside architectural considerations we discuss some of our design and implementation experiences with java

A High-Resolution Record of Atmospheric Dust Composition and Variability Since Ad 1650 from a Mount Everest Ice Core

A Mount Everest ice core analyzed at high resolution for major and trace elements (Sr, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu, Bi, U, Tl, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co) and spanning the period A. D. 1650- 2002 is used to investigate the sources of and variations in atmospheric dust through time. The chemical composition of dust varies seasonally, and peak dust concentrations occur during the winter-spring months. Significant correlations between the Everest dust record and dust observations at stations suggest that the Everest record is representative of regional variations in atmospheric dust loading. Back-trajectory analysis in addition to a significant correlation of Everest dust concentrations and the Total Ozone Mapping Spectrometer (TOMS) aerosol index indicates that the dominant winter sources of dust are the Arabian Peninsula, Thar Desert, and northern Sahara. Factors that contribute to dust generation at the surface include soil moisture and temperature, and the long-range transport of dust aerosols appears to be sensitive to the strength of 500-mb zonal winds. There are periods of high dust concentration throughout the 350-yr Mount Everest dust record; however, there is an increase in these periods since the early 1800s. The record was examined for recent increases in dust emissions associated with anthropogenic activities, but no recent dust variations can be conclusively attributed to anthropogenic inputs of dust

A spatial framework for assessing current conditions and monitoring future change in the chemistry of the Antarctic atmosphere

This is the first study to measure more than 25 chemical constituents in the surface snow and firn across extensive regions of Antarctica. It is also the first to report total- Cs concentrations. We present major ion, trace element, heavy metal, rare earth element 5 and oxygen isotope data from a series of surface snow samples and shallow firn sections collected along four US ITASE traverses across East and West Antarctica. In each sample we measure dissolved concentrations of Na+, K+, Mg2+, Ca2+, Cl−, NO− 3 , SO2− 4 , and MS− using ion chromatography and total concentrations of Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co, Na, Mg, Li, and K using 10 inductively coupled plasma sector field mass spectrometry. We also measure 18O by isotope ratio mass spectrometry. The 2002/2003 traverse began at Byrd Surface Camp, West Antarctica, and ended close to South Pole, East Antarctica. The 2003/2004 traverse began at South Pole, passed through AGO4 in central East Antarctica before turning north and finishing at 15 Taylor Dome. The combined 2006/2007 and 2007/2008 traverses started out at Taylor Dome and headed south, passing through the Byrd Glacier drainage basin and ending at South Pole. In this study, we utilize satellite remote sensing measurements of microwave backscatter and grain size to assist in the identification of glaze/dune areas across 20 Antarctica and show how chemical concentrations are higher in these areas, precluding them from containing useful high-resolution chemical climate records. The majority of the non-glaze/dune samples in this study exhibit similar, or lower, concentrations to those from previous studies. Consequently, the results presented here comprise a conservative baseline for Antarctic surface snow chemical concentra25 tions. The elements Cd, Pb, Bi, As, and Li are enriched across Antarctica relative to both ocean and upper crust elemental ratios. Global volcanic outgassing accounts for the majority of the Bi measured in East and West Antarctica and for a significant fraction of the Cd in East Antarctica. Nonetheless, global volcanic outgassing cannot account for the enriched values of Pb or As. Local volcanic outgassing from Mount Erebus may account for a significant fraction of the As and Cd in West Antarctica and for a significant fraction in East Antarctic glaze/dune areas. However, despite potential 5 contributions from local and global volcanic sources, significant concentrations of Pb, Cd, and As remain across much of Antarctica. Most importantly, this study provides a baseline from which changes in the chemistry of the atmosphere over Antarctica can be monitored under expected warming scenarios and continued intensification of industrial activities in the Southern Hemisphere