Multi-Source Emission Determination Using an Inverse-Dispersion Technique

Inverse-dispersion calculations can be used to infer atmospheric emission rates through a combination of downwind gas concentrations and dispersion model predictions. With multiple concentration sensors downwind of a compound source (whose component positions are known) it is possible to calculate the component emissions. With this in mind, a field experiment was conducted to examine the feasibility of such multi-source inferences, using four synthetic area sources and eight concentration sensors arranged in different configurations. Multi-source problems tend to be mathematically ill-conditioned, as expressed by the condition number κ. In our most successful configuration (average κ = 4.2) the total emissions from all sources were deduced to within 10% on average, while component emissions were deduced to within 50%. In our least successful configuration (average κ = 91) the total emissions were calculated to within only 50%, and component calculations were highly inaccurate. Our study indicates that the most accurate multi-source inferences will occur if each sensor is influenced by only a single source. A “progressive” layout is the next best: one sensor is positioned to “see” only one source, the next sensor is placed to see the first source and another, a third sensor is placed to see the previous two plus a third, and so on. When it is not possible to isolate any sources κ is large and the accuracy of a multi-source inference is doubtful.     

A new technique for understanding magnetosphere–ionosphere coupling using directional derivatives of SuperDARN convection flow

The purpose of this paper is to present and evaluate a new technique to better understand ionospheric convection and it’s magnetospheric drivers using convection maps derived from the Super Dual Auroral Radar Network (SuperDARN). We postulate that the directional derivative of the SuperDARN ionospheric convection flow can be used as a technique for understanding solar wind–magnetosphere–ionosphere coupling by identifying regions of strong acceleration/deceleration of plasma flow associated with drivers of magnetospheric convection such as magnetic reconnection. Thus, the technique may be used to identify the open–closed magnetic field line boundary (OCB) in certain circumstances. In this study, directional derivatives of the SuperDARN ionospheric convection flow over a four and a half hour interval on Nov. 04, 2001, is presented during which the interplanetary magnetic field was predominantly southward. At each one-minute time point in the interval the positive peak in the directional derivative of flow is identified and evaluated via comparison with known indicators of the OCB including the poleward boundary of ultraviolet emissions from three FUV detectors onboard the IMAGE spacecraft as well as the SuperDARN spectral widths. Good comparison is found between the location of the peak in the directional derivative of SuperDARN flow and the poleward boundary of ultraviolet emissions confirming that acceleration of ionospheric plasma flow is associated with magnetic reconnection and the open–closed boundary.     

Laboratory measurements and modeling of metal-humic interactions under estuarine conditions

Equilibrium dialysis was used to measure Co- and Cu-binding by an isolated peat humic acid (PHA) in controlled laboratory experiments under simulated estuarine conditions: ionic strengths of 0.005 to 0.7 M in NaCl and mixed Na-Mg-Ca chloride solutions, with trace metal concentrations of ∼5 × 10⁻⁷ M, a PHA concentration of 10 mg/L, and at constant pH values of ∼7.8 (Co and Cu) and ∼4.6 (Cu only). Generally, Co- and Cu-humic binding decreased substantially with increasing ionic strength and, in the case of Cu, with decreasing pH. The presence of seawater concentrations of Ca and Mg had a relatively small effect on Co-humic binding and no measurable effect on that of Cu under the experimental conditions. The binding data were well-described by an equilibrium speciation code (the Windermere Humic Aqueous Model, WHAM) after optimising the fits by varying the metal-proton exchange constants for humic acid within justifiable limits (i.e., within 1 standard deviation of the mean exchange constants used in the WHAM database). The main factor producing the observed variations in metal-humic binding at constant pH was the electrostatic effect on the humic molecule. WHAM was used to predict Co- and Cu-humic binding in simulations of real estuaries. Co-humic binding is predicted to be relatively unimportant (generally <5% of total Co), whereas the Cu-humic complex is likely to be the dominant species throughout an estuary. The main factors producing changes in Co- and Cu-humic binding in the real-estuary simulations are the electrostatic effect on the humic molecule, ligand competition (mainly from carbonate species) for metals, and to a lesser extent Ca and Mg competition for humic binding sites. Variations in pH are significant only at the freshwater end of an estuary. WHAM simulations also indicated that competition effects between metals are more likely to occur in freshwaters than in seawater, due to enhanced electrostatic binding at low ionic strength.     

Lower and Middle Ordovician conodonts of Laurentian affinity from blocks of limestone in the Rosroe Formation,South Mayo Trough,western Ireland and their palaeogeographic implication

The Middle Ordovician Rosroe Formation consists of some 1350 m of coarse, mainly siliciclastic to volcaniclastic sedimentary rocks, deposited in a submarine fan environment, and is restricted to the southern limb of the South Mayo Trough, western Ireland. Discrete allochthonous blocks, reaching 5 m in size, are present in the formation at several localities. Conodonts recovered from these blocks, collected from two separate locations, are of late Early and mid Mid Ordovician age. The conodonts have high conodont‐alteration indices (CAI 5) indicative of temperatures as high as 300^o to max. 480 °C; some found in the Lough Nafooey area have abnormally high indices (CAI 6), which correspond to temperatures of about 360^o to max. 550 °C. The oldest fauna is dominated by Periodon aff. aculeatus and characterized by Oepikodus evae typical of the Oepikodus evae Zone (Floian Stage; Stage Slices Fl2–3, Lower Ordovician). The younger conodont assemblage, characterized by Periodon macrodentatus associated with Oistodella pulchra, is referred to the P. macrodentatus conodont Biozone (lower Darriwilian; Stage Slices Dw1–2). The Rosroe conodont assemblages are of Laurentian affinity; comparable faunas are well known from several locations along the east to south‐eastern platform margin of Laurentia and the Notre Dame subzone of central Newfoundland, Canada. The faunal composition from the limestone blocks suggests a shelf edge to slope (or fringing carbonate) setting. The faunal assemblages are coeval with, respectively, the Tourmakeady Formation (Floian–Dapingian) and Srah Formation (Darriwilian) in the Tourmakeady Volcanic Group in the eastern part of the South Mayo Trough and probably are derived from the same or similar laterally equivalent short‐lived carbonate successions that accumulated at offshore ‘peri‐Laurentian’ islands, close to and along the Laurentian margin. During collapse of the carbonate system in the late Mid Ordovician, the blocks were transported down a steep slope and into deep‐water by debris flows, mixing with other rock types now found in the coarse polymict clastics of the Rosroe Formation. The faunas fill the stratigraphical ‘gap’ between the Lower Ordovician Lough Nafooey Volcanic Group and the upper Middle Ordovician Rosroe Formation in the South Mayo Trough and represent a brief interval conducive to carbonate accumulation in an otherwise siliciclastic‐ and volcaniclastic‐dominated sedimentary environment. Copyright © 2015 John Wiley & Sons, Ltd.     

Neogene echinoids from the Cayman Islands,West Indies: regional implications

The first fossil echinoids are recorded from the Cayman Islands. A regular echinoid, Arbacia? sp., the spatangoids Brissus sp. cf. B. oblongus Wright and Schizaster sp. cf. S. americanus (Clark), and the clypeasteroid Clypeaster sp. are from the Middle Miocene Cayman Formation. Test fragments of the mellitid clypeasteroid, Leodia sexiesperforata (Leske), are from the Late Pleistocene Ironshore Formation. Miocene echinoids are preserved as (mainly internal) moulds; hence, all species are left in open nomenclature because of uncertainties regarding test architecture. All Miocene taxa are recorded from single specimens apart from the 27 assigned to Brissus. Schizaster sp. cf. S. americanus (Clark) is compared to a species from the Oligocene of the south‐east USA. Brissus sp. cf. B. oblongus is close in gross morphology to a taxon from the Miocene of Malta. Leodia sexiesperforata is identified from fragments with confidence, being the only extant Antillean sand dollar with elongate ambulacral petals that is limited to carbonate substrates. The Miocene echinoids of Grand Cayman, although of limited diversity, are mainly comprised of genera common in comparable mid‐Cenozoic carbonate environments. Copyright © 2015 John Wiley & Sons, Ltd.     

Umbral oscillations and penumbral waves in Hα

We present examples of umbral oscillations observed on Big Bear H filtergram movies and investigate the relation between umbral oscillations and running penumbral waves occurring in the same sunspot. Umbral oscillations near the center of the umbra are probably physically independent of the penumbral waves because the period of these umbral oscillations (150 s) is shorter than the penumbral wave period (270 s) but not a harmonic. We also report dark puffs which emerge from the edge of the umbra and move outward across the penumbra, and which have the same period as the running penumbral waves. We interpret these dark puffs to be the extension of chromospheric umbral oscillations at the edge of the umbra. It is suggested that the dark puffs and the running penumbral waves have a common source: photospheric oscillations just inside the umbra.     

Something old,something new,something red,something blue*

Abstract

Hydrologists responsible for flood management need real-time data in order to manage imminent or ongoing floods. In this paper, innovative methods for accessing hydrological data and their spatial visualization are introduced. A multitude of relevant real-time, forecast and historical information is provided in a single, self-updating hydrological map information system. The system consists of a central database and a cartographic user interface and provides harmonized and filtered data in the form of interactive, customizable maps. Maps may also be cross-referenced with historical maps or may be animated for improved comprehension and decision making. Emphasis is placed on the development of the hydrological real-time database that manages large amounts of spatial, temporal and attributive data. The paper focuses on the cartographic user interface, its functionality and the resulting interactive hydrological maps.

Citation Lienert, C., Weingartner, R. &; Hurni, L. (2011) An interactive, web-based, real-time hydrological map information system. Hydrol. Sci. J. 56(1), 1–16