The greening of the McGill Paleoclimate Model. Part I: Improved land surface scheme with vegetation dynamics

The formulation of a new land surface scheme (LSS) with vegetation dynamics for coupling to the McGill Paleoclimate Model (MPM) is presented. This LSS has the following notable improvements over the old version: (1) parameterization of deciduous and evergreen trees by using the models climatology and the output of the dynamic global vegetation model, VECODE (Brovkin et al. in Ecological Modelling 101:251–261 (1997), Global Biogeochemical Cycles 16(4):1139, (2002)); (2) parameterization of tree leaf budburst and leaf drop by using the models climatology; (3) parameterization of the seasonal cycle of the grass leaf area index; (4) parameterization of the seasonal cycle of tree leaf area index by using the time-dependent growth of the leaves; (5) calculation of land surface albedo by using vegetation-related parameters, snow depth and the models climatology. The results show considerable improvement of the models simulation of the present-day climate as compared with that simulated in the original physically-based MPM. In particular, the strong seasonality of terrestrial vegetation and the associated land surface albedo variations are in good agreement with several satellite observations of these quantities. The application of this new version of the MPM (the green MPM) to Holocene millennial-scale climate changes is described in a companion paper, Part II.

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Palaeoproterozoic evaporites in Fennoscandia: implications for seawater sulphate, the rise of atmospheric oxygen and local amplification of the δ13C excursion

This paper addresses global oxygenation and establishment of a marine sulphate reservoir in the Palaeoproterozoic. We report syn-depositional, marine, anhydrite-containing pseudomorphs after Ca-sulphates as widespread throughout the Tulomozero Formation in the SE Fennoscandian Shield, implying that surface waters were oxidized and a large SO marine reservoir was developed as early as 2100 Ma. The Ca-sulphates and associated magnesite and halite precipitated syn-depositionally from oxidized, evolved and modified seawater in coastal playa, sabkha and intertidal flat settings. ⁸⁷Sr/⁸⁶Sr and δ¹³C of associated ¹³C-rich stromatolitic dolostones were environmentally controlled with the highest ratios occurring in playa and sabkha carbonates. The results imply that the Palaeoproterozoic δ¹³C_carb excursion was amplified by 8‰ by local environmental factors and calls into question many observations of putative δ¹³C global signals reported previously from similar Palaeoproterozoic, evaporitic, dolostones. The local environmental amplification can explain a large regional and intercontinental δ¹³C discrepancy observed in synchronous carbonates.     

Historical Climatology In Europe – The State Of The Art

This paper discusses the state of European research in historical climatology. This field of science and an overview of its development are described in detail. Special attention is given to the documentary evidence used for data sources, including its drawbacks and advantages. Further, methods and significant results of historical-climatological research, mainly achieved since 1990, are presented. The main focus concentrates on data, methods, definitions of the “Medieval Warm Period” and the “Little Ice Age”, synoptic interpretation of past climates, climatic anomalies and natural disasters, and the vulnerability of economies and societies to climate as well as images and social representations of past weather and climate. The potential of historical climatology for climate modelling research is discussed briefly. Research perspectives in historical climatology are formulated with reference to data, methods, interdisciplinarity and impacts.     

Continental drift and the rotation of the earth-a new and critical evaluation

Sconzo has proposed that the continental drift of a land mass like Greenland can make a detect-able change in the Earth's rotation rate through a change in the Earth's moment of inertia. The correction of theoretical and numerical errors in his paper results in a change in the length of the day of only 3.5×10^–8 s cy^–1, a rate which is 6 orders of magnitude less than the value he gives. Continental drift does not appear to cause an important change in the length of the day.     

Die Verölung der Oberflächengewässer durch die Kleinschiffahrt

Ohne Zusammenfassung     

RESIDENTIAL PREFERENCE PATTERNS OF AFRO-AMERICAN COLLEGE STUDENTS IN THREE DIFFERENT STATES

The residential preferences of Afro-American students in three black colleges in Pennsylvania, North Carolina, and Texas are factor analyzed to determine whether major differences exist. Mapping the factor scores for the students in each college reveals that state rankings vary markedly from one region to another, black spatial preferences differ markedly from those students attending predominately white universities, and preference patterns reflect contemporary interregional black migration trends.     

Generation of flow nets using fem nodal potentials and bilinear shape functions

A method for generating both equipotential lines and streamlines directly based upon nodal potentials and bilinear shape functions is presented. The method involves post-processing a finite element (FE) solution utilizing typical four-node isoparametric quadrilateral elements. The application of the method can be important in the interpretation of FE analysis results, especially when inhomogeneous, anisotropic, unconfined or/and other complicated conditions exist. Compared with conventional techniques to generate flow nets which depend upon both the potential and stream functions, the method presented is simpler and more powerful.     

Sediment disturbance off the Tagus Estuary, Western Portugal: chronic contamination, sewage outfall operation and runoff events

Sediment disturbance patterns in the coastal area off the Tagus Estuary (Portugal) have been assessed using a set of combined techniques. The potential sources of disturbance in the area include chronic contamination of the fine sediments originating from the estuary, a local input from a long-sea sewage outfall and occasional high runoff episodes following torrential rain. The Sediment Quality Triad approach, combining environmental chemistry (namely organic contaminants), macrofaunal benthic communities and laboratory sediment toxicity assays, was performed on sediment samples from 20 sites. The samples were collected before the outfall commenced operation and four years after commissioning, in order to evaluate the relative magnitudes of the three potential sources of disturbance. The sediment contamination created by the estuary was identified as the most important cause of reduced sediment quality, as disturbance in all three components of the Sediment Quality Triad were only found in a site located near the estuary.