bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Profundus Splint for Flexor Profundus Repair
Authors: REIS N. D.
Published: March 2006

Flexor profundus is a mass action muscle so that when we fully extend one finger including full extension of the distal joint the entire muscle is pulled distally.

By fully flexing the injured or operated finger at the metacarpophalangeal joint and fully extending the adjacent fingers, flexor digitorum profundus of the operated finger is made so redundant as to abolish all tension at the suture line.

The position of the operated finger: metacarpophalangeal joint flexion with interphalangeal joint extension is ideal for the preservation of joint mobility and therefore ideal for the restoration of movement when the repaired flexor tendon is mobilized.

It is permissible to splint a healthy finger in full extension for three weeks.
Congenital Metacarpal Malformation
Authors: DELISS LOUIS
Published: March 2006

The findings in two brothers are described in whom there are similar isolated defects of development of their fifth metacarpal bones with normal fingers. There is no evidence of further skeletal, or biochemical abnormality. A mutational genetic basis is postulated.
Complications of Radial Artery Catheterization
Authors: CROSSLAND STANLEY G. , NEVIASER ROBERT J.
Published: March 2006

Sixty patients, representing a ten per cent incidence of complications, developed ischaemic or necrotic changes in the involved hand following radial artery cannulation. The loss of digits or hands could have been avoided by adequate evaluation of the vascular status of the hand both before and after cannulation.
Osteoid Osteoma of the Terminal Phalanges
Authors: GIANNIKAS A. , PAPACHRISTOU G. , TINIAKOS G. , CHRYSAFIDIS G. , HARTOFILAKIDIS-GAROFALIDIS G.
Published: March 2006

Four cases of osteoid osteoma of the terminal phalanx — a very rare location — are presented. The clinical picture of all cases is essentially the same, gradual swelling of the terminal phalanx with enlargement of the nail and pain, particularly at night and relievable by aspirin. The treatment was operative and of double value. 1. The osteoid osteoma is removed; 2. Cosmetic result is obtained by reduction of the size of the terminal phalanx.
Knuckle Pads in Dupuytren’s Disease
Authors: MIKKELSEN OTTO A.
Published: March 2006

Knuckle pads are not exclusively found in persons with Dupuytren’s disease, but they occur four times more often in these patients than in the general population (in Norway). Occurrence of knuckle pads in persons with Dupuytren’s disease does not seem to imply a higher predisposition or a more aggressive disease.
Trends in the abundance of Cantabrian Capercaillie Tetrao urogallus cantabricus at leks on the southern slope of the Cantabrian Mountains, north-west Spain
Authors: POLLO CÉSAR J. , ROBLES LUIS , SEIJAS JUAN M. , GARCÍA-MIRANDA ÁNGEL , OTERO RAFAEL
Published: March 2006

We analysed the trend of the number of singing males of Cantabrian Capercaillie Tetrao urogallus cantabricus in 207 leks on the southern slope of the Cantabrian mountains, north-west Spain, in the period 1981 to 2003. The area of occupancy in 1981–1982 covered up to approximately 2,070 km2, but in 2000–2003 it was 693 km2, a 66% area reduction in 22 years. The 1981–1982 census estimated a minimum number of 274 singing male Capercaillie on the southern slope, but in 2000–2003 only an estimated 81 males were recorded, a reduction of 70%. A linear regression was used to detect and describe the changes in the size of the total population of the southern slope as well as individual subpopulations. The overall trend for the total subpopulations was a significant decrease in the number of males (y = 39.94−0.018x; R2 = 0.944, P < 0.001). The negative regression slopes indicated that the number of males had fallen in all the subpopulations considered. In the western core area the greatest annual mean rate of decline was detected in the Sierra de Picos de Ancares subpopulation (−6.22%) and in the eastern core in the Sierra de Riaño subpopulation (−3.43%). The principal local limiting factors (habitat fragmentation, human disturbance, small population size and competition) that have caused the population decline are discussed, together with the demographic, genetic and evolutionary consequences for the surviving subpopulations.
Factors influencing nest-site occupancy and low reproductive output in the Critically Endangered Yellow-crested Cockatoo Cacatua sulphurea on Sumba, Indonesia
Authors: WALKER JONATHAN S. , CAHILL ALEXIS J. , MARSDEN STUART J.
Published: March 2006

We studied nest-site selection and nesting success in the critically endangered Yellow-crested Cockatoo Cacatua sulphurea throughout a breeding season in Manupeu-Tanadaru National Park, Sumba. Within a 6 km2 study area, which supported about 60 birds, cockatoos displayed disproportionate interest in cavities in trees containing other active nests, and cavities already actually occupied by parrots or owls. Actual nesting attempts were made at only eight cavities, and a single chick fledged. Interspecific interactions were observed at every one of these nests. Breeding activity was negatively correlated with monthly rainfall, which was the heaviest for at least 10 years, and it is possible that adverse weather conditions disrupted cockatoo nesting this season. Whether this is the case or not, our study shows how low reproductive output can be in the species and this has serious implications for survival of the population on Sumba.
First ornithological inventory and conservation assessment for the yungas forests of the Cordilleras Cocapata and Mosetenes, Cochabamba, Bolivia
Authors: MACLEOD ROSS , EWING STEVEN K. , HERZOG SEBASTIAN K. , BRYCE ROSALIND , EVANS KARL L. , MACCORMICK AIDAN
Published: March 2006

Bolivia holds one of the world's richest avifaunas, but large areas remain biologically unexplored or unsurveyed. This study carried out the first ornithological inventory of one of the largest of these unexplored areas, the yungas forests of Cordilleras Cocapata and Mosetenes. A total of 339 bird species were recorded including 23 restricted-range, four Near-Threatened, two globally threatened, one new to Bolivia and one that may be new to science. The study extended the known altitudinal ranges of 62 species, 23 by at least 500 m, which represents a substantial increase in our knowledge of species distributions in the yungas, and illustrates how little is known about Bolivia's avifauna. Species characteristic of, or unique to, three Endemic Bird Areas (EBAs) were found. The Cordilleras Cocapata and Mosetenes are a stronghold for yungas endemics and hold large areas of pristine Bolivian and Peruvian Upper and Lower Yungas habitat (EBAs 54 and 55). Human encroachment is starting to threaten the area and priority conservation actions, including designation as a protected area and designation as one of Bolivia's first Important Bird Areas, are recommended.
Reproductive performance and nest-site selection of White-naped Cranes Grus vipio in the Ulz river valley, north-eastern Mongolia
Authors: BRADTER UTE , GOMBOBAATAR SUNDEV , UUGANBAYAR CHULUUNBAATAR , GRAZIA TRACY E. , EXO KLAUS-MICHAEL
Published: March 2006

North-eastern Mongolia is an important breeding area for the globally threatened White-naped Crane Grus vipio. We studied reproductive performance and the influence of factors related to livestock grazing on reproduction and nest-site selection of the White-naped Crane population in the Ulz river valley, north-eastern Mongolia in 2000 and 2001. In 2001, 42 territorial pairs were found in 270 km of river basin. Recruitment was 18–22% resulting in 0.5–0.6 juveniles per territorial pair. The years 2000 and 2001 were within a dry period and recruitment might have been below the long-term average. White-naped Crane nests were significantly associated with river basin sections containing shallow water-bodies. The number and extent of shallow water-bodies are likely to be a limiting factor for breeding population size. Nest-sites in water-bodies were selected for high nest concealment, but nests were initiated even when concealing vegetation was not available. Only 26% of nests were >90% concealed suggesting that appropriate cover was often not available. Nest-sites were also selected for low grazing intensity. No correlation was found between hatching or fledging success and nest concealment or grazing intensity. Brood-size of successful pairs was higher if the home range was ungrazed, but further investigations are needed to clarify whether this was caused by absence of livestock grazing or other factors. Both because of internationally important numbers and because of a potentially high reproductive output, the study area is of high importance for the species.
Paleoseismic evidence of great surface rupture earthquakes along the Indian Himalaya
Authors: Kumar Senthil , Wesnousky Steven G. , Rockwell Thomas K. , Briggs Richard W. , Thakur Vikram C. , Jayangondaperumal R.
Published: March 2006

Toward understanding the relationship between strain accumulation and strain release in the context of the mechanics of the earthquake and mountain building process and quantifying the seismic hazard associated with the globes largest continental thrust system, we describe the late Quaternary expression and paleoseismic evidence for great surface rupture earthquakes at six sites along the Himalayan Frontal Thrust (HFT) system of India. Our observations span a distance of ∼250 km along strike of the HFT. Uplifted and truncated fluvial terrace deposits resulting from the Holocene displacements on the HFT are preserved along canyons of the Ghaggar, Markanda, Shajahanpur, and Kosi Rivers. Dividing the elevation of the bedrock straths at each site by their ages yields estimates of the vertical uplift rate of ∼4–6 mm/yr, which when assumed to be the result of slip on an underlying thrust dipping at ∼20°–45° are equivalent to fault slip rates of ∼6–18 mm/yr or shortening rates of ∼4–16 mm/yr. Trench exposures reveal the HFT to fold and break late Holocene surface sediments near the cities and villages of Chandigarh, Kala Amb, Rampur Ganda, Lal Dhang, and Ramnagar. Radiocarbon ages of samples obtained from the displaced sediments indicate surface rupture at each site took place after ∼A.D. 1200 and before ∼A.D. 1700. Uncertainties attendant to the radiocarbon dating currently do not allow an unambiguous definition of the capping bound on the age of the displacement at each site and hence whether or not the displacements at all sites were contemporaneous. Trench exposures and vertical separations measured across scarps at Rampur Ganda, Lal Dhang, and Ramnagar are interpreted to indicate single‐event displacements of ∼11–38 m. Dividing the observed single‐event vertical components of displacement by the estimated longer‐term uplift rates indicates ∼1330–3250 or more years should be required to accumulate the slip sufficient to produce similar sized displacements. Surface rupture appears to not have occurred during the historical 1905 Kangra (Mw= 7.7), 1934 Bihar‐Nepal (Mw= 8.1), and 1950 Assam (Mw= 8.4) earthquakes, which also occurred along the Himalayan front. Yet we observe clear evidence of fault scarps and displacements in young alluvium and progressive and continued offset of fluvial terrace deposits along the HFT. We suggest on this basis and the size and possible synchroneity of displacements recorded in the trenches that there exists the potential for earthquakes larger than recorded in the historical record and with the potential to rupture lengths of the HFT greater than the ∼250 km we have studied.
Modeling δ18O in tropical precipitation and the surface ocean for present‐day climate
Authors: Brown J. , Simmonds I. , Noone D.
Published: March 2006

The Melbourne University atmospheric general circulation model with stable water isotope tracers is used to examine the variability of isotopic ratios of precipitation and the surface ocean in the tropics for present‐day (1950–1999) climate. Surface ocean isotopic ratios are simulated interactively using a one‐dimensional scheme that reproduces key features of the observed tropical isotopic spatial distribution and seasonal and interannual variability. The seasonal and interannual variability of modeled isotopic ratios of tropical precipitation is strongly associated with changes in precipitation amount, in agreement with previous isotopic modeling studies. Modeled isotopic ratios of both precipitation and surface ocean water respond to El Niño–Southern Oscillation (ENSO), although the spatial patterns of ENSO and monsoon isotopic responses differ from observations because of biases in the simulated tropical climate. The model captures the dependence of the interannual variability of precipitation isotopic ratios over the tropical Andes on local temperature and precipitation variability and moisture balance over the Amazon basin but fails to reproduce a significant ENSO precipitation or isotope signal over this region. Modeled precipitation isotopic ratios are significantly correlated with local precipitation amount but not with local or regional temperature at Tibetan Plateau ice core sites on interannual timescales, in disagreement with the interpretation of these ice core records as temperature proxies. Surface ocean isotopic ratios are used to calculate modeled “coral,” isotopic ratios which are compared with modern coral records, reproducing observed interannual variability where precipitation is well simulated.
Particulate iron dynamics during FeCycle in subantarctic waters southeast of New Zealand
Authors: Frew R. D. , Hutchins D. A. , Nodder S. , Sanudo‐Wilhelmy S. , Tovar‐Sanchez A. , Leblanc K. , Hare C. E. , Boyd P. W.
Published: March 2006

The FeCycle experiment provided an SF6 labeled mesoscale patch of high‐nitrate low‐chlorophyll (HNLC) water in austral summer 2003. These labeled waters enabled a comparison of the inventory of particulate iron (PFe) in the 45‐m‐deep surface mixed layer with the concurrent downward export flux of PFe at depths of 80 and 120 m. The partitioning of PFe between four size fractions (0.2–2, 2–5, 5–20, and >20 μm) was assessed, and PFe was mainly found in the >20‐μm size fraction throughout FeCycle. Estimates of the relative contribution of the biogenic and lithogenic components to PFe were based on an Al:Fe molar ratio (0.18) derived following analysis of dust/soil from the nearest source of aerosol Fe: the semi‐arid regions of Australia. The lithogenic component dominated each of the four PFe size fractions, with medians ranging from 68 to 97% of PFe during the 10‐day experiment. The Fe:C ratios for mixed‐layer particles were ∼40 μmol/mol. PFe export was ∼300 nmol m−2 d−1 at 80 m depth representing a daily loss of ∼1% from the mixed‐layer PFe inventory. There were pronounced increases in the Fe:C particulate ratios with depth, with a five‐fold increase from the surface mixed layer to 80 m depth, consistent with scavenging of the remineralized Fe by sinking particles and concurrent solubilization and loss of particulate organic carbon. Significantly, the lithogenic fraction of the sinking PFe intercepted at both 80 m and 120 m was >40%; that is, there was an approximately twofold decrease in the proportion of lithogenic iron exported relative to that in the mixed‐layer lithogenic iron inventory. This indicates that the transformation of lithogenic to biogenic PFe takes place in the mixed layer, prior to particles settling to depth. Moreover, the magnitude of lithogenic Fe supply from dust deposition into the waters southeast of New Zealand is comparable to that of the export of PFe from the mixed layer, suggesting that a large proportion of the deposited dust eventually exits the surface mixed layer as biogenic PFe in this HNLC region.
What controls CCN seasonality in the Southern Ocean? A statistical analysis based on satellite‐derived chlorophyll and CCN and model‐estimated OH radical and rainfall
Authors: Vallina S. M. , Simó R. , Gassó S.
Published: March 2006

A 3‐year time series set (from January 2002 to December 2004) of monthly means of satellite‐derived chlorophyll (CHL) and cloud condensation nuclei (CCN), as well as model outputs of hydroxyl radical (OH), rainfall amount (RAIN), and wind speed (WIND) for the Southern Ocean (SO, 40°S–60°S) is analyzed in order to explain CCN seasonality. Chlorophyll is used as a proxy for oceanic dimethylsulfide (DMS) emissions since both climatological aqueous DMS and atmospheric methanesulfonate (MSA) concentrations are tightly coupled with chlorophyll seasonality over the Southern Ocean. OH is included as the main atmospheric oxidant of DMS to produce CCN, and rainfall amount as the main loss factor for CCN through aerosol scavenging. Wind speed is used as a proxy for sea salt (SS) particles production. The CCN concentration seasonality is characterized by a clear pattern of higher values during austral summer and lower values during austral winter. Linear and multiple regression analyses reveal high significant correlations between CCN and the product of chlorophyll and OH (in phase) and rainfall amount (in antiphase). Also, CCN concentrations are anticorrelated with wind speed, which shows very little variability and a slight wintertime increase, in agreement with the sea salt seasonality reported in the literature. Finally, the fraction of the total aerosol optical depth contributed by small particles (ETA) exhibits a seasonality with a 3.5‐fold increase from austral winter to austral summer. The biogenic contribution to CCN is estimated to vary between 35% (winter) and 80% (summer). Sea salt particles, although contributing an important fraction of the CCN burden, do not play a role in controlling CCN seasonality over the SO. These findings support the central role of biogenic DMS emissions in controlling not only the number but also the variability of CCN over the remote ocean.
Toward a self‐consistent, high‐resolution absolute plate motion model for the Pacific
Authors: Wessel Paul , Harada Yasushi , Kroenke Loren W.
Published: March 2006

The hot spot hypothesis postulates that linear volcanic trails form as lithospheric plates move relative to stationary or slowly moving plumes. Given geometry and ages from several trails, one can reconstruct absolute plate motions (APM) that provide valuable information about past and present tectonism, paleogeography, and volcanism. Most APM models have been designed by fitting small circles to coeval volcanic chain segments and determining stage rotation poles, opening angles, and time intervals. Unlike relative plate motion (RPM) models, such APM models suffer from oversimplicity, self‐inconsistencies, inadequate fits to data, and lack of rigorous uncertainty estimates; in addition, they work only for fixed hot spots. Newer methods are now available that overcome many of these limitations. We present a technique that provides high‐resolution APM models derived from stationary or moving hot spots (given prescribed paths). The simplest model assumes stationary hot spots, and an example of such a model is presented. Observations of geometry and chronology on the Pacific plate appear well explained by this type of model. Because it is a one‐plate model, it does not discriminate between hot spot drift or true polar wander as explanations for inferred paleolatitudes from the Emperor chain. Whether there was significant relative motion within the hot spots under the Pacific plate during the last ∼70 m.y. is difficult to quantify, given the paucity and geological uncertainty of age determinations. Evidence in support of plume drift appears limited to the period before the 47 Ma Hawaii‐Emperor Bend and, apart from the direct paleolatitude determinations, may have been somewhat exaggerated.
Influence of coal based thermal power plants on aerosol optical properties in the Indo‐Gangetic basin
Authors: Prasad Anup K. , Singh Ramesh P. , Kafatos Menas
Published: March 2006

The Indo‐Gangetic basin is characterized by dense fog, haze and smog during the winter season. Here, we show one to one correspondence during the winter season of aerosol optical properties with the location of thermal power plants which are single small spatial entities compared to the big cities. Our results indicate that power plants are the key point source of air pollutants. The detailed analysis of aerosol parameters deduced from the Multiangle Imaging SpectroRadiometer (MISR) level 3 remote sensing data show the existence of absorbing and non‐absorbing aerosols emitted from these plants. Analysis of higher resolution Moderate Resolution Imaging Spectroradiometer (MODIS) level 2 aerosol optical depth over thermal power plants supports the findings.
Tracking magma dynamics by laser ablation (LA)‐ICPMS trace element analysis of glass in volcanic ash: The 1995 activity of Mt. Etna
Authors: Schiavi F. , Tiepolo M. , Pompilio M. , Vannucci R.
Published: March 2006

Glass fragments in tephra erupted at Mt. Etna from May to December 1995 have been analyzed by laser ablation ICPMS. The trace element compositional variability of ashes deposited during this interval reveals the presence of discrete magma batches with different crystallization degrees in the shallow plumbing system. From May to October a highly crystalline magma is predominant within the conduit with only minor sporadic input of fresh and more primitive magma batches. After October new and less evolved magma batches become more prevalent and become progressively homogenized within more evolved resident magma. In December ashes closely match the chemistry of the volcanics subsequently erupted till February 1996. This study demonstrates that the trace element characterization of ashes has important implications for volcanic monitoring and is a useful tool for the forecasting of paroxysmal events at Mt. Etna.
Variability of the tropical and subtropical ocean surface latent heat flux during 1989–2000
Authors: Liu Jiping , Curry Judith A.
Published: March 2006

We assess the consistencies and discrepancies of the interannual variability and decadal trend of the ocean surface latent heat flux (LHF) for the period 1989–2000 among two satellite‐based data sets and two reanalysis products over the tropics and subtropics. The data sets show encouraging agreement on the spatial/temporal variations of the LHF, particularly during 1992–1997, but some discrepancies are noticed. These discrepancies are primarily caused by the differences of the input meteorological state variables used to calculate LHF, particularly for the air specific humidity. Both the satellite‐based data sets and reanalysis products show a statistically significant decadal‐scale positive trend in the LHF, which is independent of the El Niño‐Southern Oscillation, with the strongest trends in the subtropical Southeast Pacific and Southeast Indian Ocean. This trend in the LHF is associated primarily with an increasing trend of the surface wind speed.
Comparisons of remote sensing retrievals and in situ measurements of aerosol fine mode fraction during ACE‐Asia
Authors: Gassó Santiago , O'Neill Norm
Published: March 2006

We present sunphotometer‐retrieved and in situ fine mode fractions (FMF) measured onboard the same aircraft during the ACE‐Asia experiment. Comparisons indicate that the latter can be used to identify whether the aerosol under observation is dominated by a mixture of modes or a single mode. Differences between retrieved and in situ FMF range from 5–20%. When profiles contained multiple layers of aerosols, the retrieved and measured FMF were segregated by layers. The comparison of layered and total FMF from the same profile indicates that columnar values are intermediate to those derived from layers. As a result, a remotely sensed FMF cannot be used to distinguish whether the aerosol under observation is composed of layers each with distinctive modal features or all layers with the same modal features. Thus, the use of FMF in multiple layer environments does not provide unique information on the aerosol under observation.
Shear‐wave splitting beneath the southwestern Kurile arc and northeastern Japan arc: A new insight into mantle return flow
Authors: Nakajima Junichi , Shimizu Jumpei , Hori Shuichiro , Hasegawa Akira
Published: March 2006

Shear‐wave splitting in the southwestern part of the Kurile arc and the northeastern (NE) Japan arc is investigated using the waveforms from local earthquakes. For both arcs observed shear‐wave splitting shows clear evidence for a striking rotation of fast direction across the arc, suggesting the different feature of anisotropy between the fore‐arc and back‐arc sides. Trench‐parallel fast directions are observed in the fore‐arc side, which is consistent with the anisotropy expected from the deformation of the B‐type olivine fabric as well as the anisotropy in the slab. Fast directions observed in the back‐arc side show approximately E‐W and ESE‐WNW in the NE Japan arc and N‐S in the southwestern Kurile arc, which are characterized by the local maximum‐dip direction of the subducted Pacific plate not by the direction of plate convergence. This relationship suggests that the direction of the mantle return flow is governed by the local slab geometry.
Satellite observation of chlorophyll and nutrients increase induced by Typhoon Megi in the Japan/East Sea
Authors: Son SeungHyun , Platt Trevor , Bouman Heather , Lee DongKyu , Sathyendranath Shubha
Published: March 2006

Remotely‐sensed sea surface temperature (SST) and chlorophyll data were used to assess the biological response to the Typhoon Megi in the Japan/East Sea (JES). Mean SST from in situ measurements and satellite data decreased by about 2–4°C in the JES after Typhoon Megi. Mean concentration of MODIS chlorophyll in the post–typhoon period increased by about 70% along the typhoon passage. The cold, nutrient‐rich waters entrained into the surface layer lead to an enhancement of phytoplankton growth. Typhoon‐induced variability of nitrate, phosphate, and silicate at the sea surface of the JES were derived from the MODIS SST using a nutrient‐temperature relationship based on in situ measurements. After the passage of the typhoon, there were increases in NO3, PO4, and SiO2 by about 90%, 40%, and 35%, respectively. The nutrient flux brought into the surface water by the storm‐induced mixing has the potential to support new production.
Direct observations of injection events of subauroral plasma into the polar cap
Authors: Carlson H. C. , Moen J. , Oksavik K. , Nielsen C. P. , McCrea I. W. , Pedersen T. R. , Gallop P.
Published: March 2006

While polar cap ionospheric patches have been studied for over two decades, there remains no general agreement to which of many proposed patch‐production mechanisms are important or dominate. An experiment was designed and implemented to search for transient events redirecting subauroral ionospheric plasma from its subauroral flow to transient injection into the polar cap, as would occur for the (Lockwood and Carlson, 1992) mechanism of patch creation. An earlier experiment provided compelling evidence of this mechanism acting within the cusp, with strong but indirect evidence regarding the source‐reservoir for the plasma injected into the polar cap. The work here, for the first time, directly tracks plasma becoming a “patch”, continuously from subauroral latitudes before the event fires, through the cusp and into the polar cap. We conclude this mechanism is a dominant patch generation mechanism and highlight that poleward‐moving‐form research has direct application to polar cap patch generation by magnetopause reconnection.
Small ice crystals and the climatology of lightning
Authors: Sherwood Steven C. , Phillips Vaughan T. J. , Wettlaufer J. S.
Published: March 2006

Vigorous debate still surrounds the cloud electrification process and unexplained regional variations in lightning activity. Here, we show that climatological maxima in lightning activity are associated with small effective diameter De of ice crystals near cumulonimbus cloud tops. This relationship, unlike lightning's more well‐known relationship with cloud top height, is consistent over land and ocean. Since multiple studies indicate that De is reduced by atmospheric aerosol, this relationship strengthens previous suggestions of a role for aerosols as well as dynamics in electrification. Moreover, the angular distribution of backscattered radiance shows that modest (∼10%) De decreases reflect large (∼2×) increases in the number of small (<∼30 μm) particles N, a finding supported by cloud model simulations. Both relationships provide an important new test of cloud microphysics and/or electrification models.
Ionospheric erosion by Alfvén waves
Authors: Chaston C. C. , Genot V. , Bonnell J. W. , Carlson C. W. , McFadden J. P. , Ergun R. E. , Strangeway R. J. , Lund E. J. , Hwang K. J.
Published: March 2006

Using observations from the FAST small explorer spacecraft, we present fields and plasma observations above the dayside auroral oval showing the erosion of ionospheric plasmas from the topside ionosphere by the action of Alfvén waves. Using interferometric techniques, the waves are shown to approximately obey the expected dispersion for Alfvén waves with transverse scales extending from greater than electron inertial lengths down to ion gyroradii. Measurements of the plasma density where these waves are observed show that over latitudinal widths exceeding 100 km total depletion of the cold ionospheric plasma can occur. These depleted regions or cavities are populated by magnetosheath plasmas, upgoing transversely accelerated ionospheric ions, and downgoing field‐aligned electrons. The ionospheric ions and field‐aligned electrons are distributed as conics and beams, respectively. Poynting flux observations on the density gradients comprising the cavity walls show that these waves are directed downward and focused inward toward regions of lower density. Wave phase velocity measurements, while subject to significant uncertainty, show that the wave vector is directed transversely outward from the cavity. These observations suggest a feedback model for Alfvén wave focusing and ion heating on density gradients that can lead to intense ion outflow from the ionosphere and subsequent depletion of ionospheric plasmas.
Predicting macroscopic transport properties using microscopic image data
Authors: Fredrich J. T. , DiGiovanni A. A. , Noble D. R.
Published: March 2006

We consider eight data sets obtained from synchrotron computed microtomographic experiments performed on natural and synthetic sandstones at the GSECARS 13‐BM beam line at the Advanced Photon Source. Four data sets were collected on glass bead packs sintered to differing bulk densities; each of these data sets contains just over 225 million voxels (661 × 661 × 517), with voxel resolution of 3.34 μm. The other four data sets were collected from a single sample of natural sandstone. For the natural sandstone, three data sets were collected from different subvolumes within the sample, with these three data sets identical in size and resolution to those acquired for the sintered glass bead packs. A fourth data set was collected for one of the same subvolumes but at twice the resolution; this data set contains just over 1.6 billion voxels (1327 × 1327 × 920), with voxel resolution of 1.67 μm. Following processing to extract binary descriptions of the two‐phase (solid and pore) structure, the image data are analyzed to calculate porosity and specific surface area. The binarized image data are applied directly in massively parallel numerical simulations of single‐phase fluid flow performed using the lattice Boltzmann method; development of novel boundary conditions to facilitate efficient handling of these very large data sets is also described. The permeabilities predicted from 1 to 3 mm3 image volumes characterized at a length scale of ∼1.7–3.4 μm are compared to experimental measurements of intrinsic permeability performed at bench conditions on standard core‐sized samples (25.4 mm in diameter × 50.8 mm in length, or ∼26 cm3). The macroscopic permeability computed from the image data agree remarkably well with the experimentally measured bulk permeability over several orders of magnitude range in permeability and equate to over 4 orders of magnitude scale‐up. The results provide insight on the representative volume and length scales necessary to characterize geometrically complex porous media and predict fluid transport properties at the macroscale.
Comparison of in situ aerosol extinction and scattering coefficient measurements made during the Aerosol Intensive Operating Period
Authors: Strawa A. W. , Elleman R. , Hallar A. G. , Covert D. , Ricci K. , Provencal R. , Owano T. W. , Jonsson H. H. , Schmid B. , Luu A. P. , Bokarius K. , Andrews E.
Published: March 2006

In May 2003, the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program sponsored the Aerosol Intensive Operating Period (AIOP) which was conducted over the ARM Climate Research Facility (ACRF) in central Oklahoma. One new instrument that flew in the AIOP, called Cadenza, employed a cavity ring‐down technique to measure extinction coefficient and a reciprocal nephelometer technique to simultaneously measure scattering coefficient. This instrument is described in this paper, and measurements are compared to those of conventional instrumentation. Agreement between Cadenza extinction coefficient and that derived from combining nephelometer scattering and PSAP absorption (Neph + PSAP) was excellent, about 2%. Agreement between Cadenza scattering coefficient and TSI nephelometer scattering was also excellent, about 2%, well within the uncertainty of the nephelometer and Cadenza scattering measurements. Comparisons between these instruments, made for the special case of plumes, showed that Cadenza measured extinction and scattering several percent higher on average than the Neph + PSAP and nephelometer alone. This difference is likely due to differences in the instrument response time: The response time for Cadenza is 1 s while that for the nephelometer is a minimum of 8 s. Plumes, identified as originating from Siberian biomass burning, are characterized. Composite size distributions from wing‐mounted probes showed that two of the plumes had significant large particle modes that resulted in high values of the effective radius. The effect of the large particle mode was not seen in the Ångström coefficient calculated from the in‐cabin scattering measurements because of the characteristics of the aircraft inlet.
Ozone ensemble forecasts: 1. A new ensemble design
Authors: Delle Monache Luca , Deng Xingxiu , Zhou Yongmei , Stull Roland
Published: March 2006

A new Ozone Ensemble Forecast System (OEFS) is tested as a technique to improve the accuracy of real‐time photochemical air quality modeling. The performance of 12 different forecasts along with their ensemble mean is tested against the observations during 11–15 August 2004, over five monitoring stations in the Lower Fraser Valley, British Columbia, Canada, a population center in a complex coastal mountain setting. The 12 ensemble members are obtained by driving the U.S. Environmental Protection Agency (EPA) Models‐3/Community Multiscale Air Quality Model (CMAQ) with two mesoscale meteorological models, each run at two resolutions (12‐ and 4‐km): the Mesoscale Compressible Community (MC2) model and the Penn State/NCAR mesoscale (MM5) model. Moreover, CMAQ is run for three emission scenarios: a control run, a run with 50% more NOx emissions, and a run with 50% fewer. For the locations and days used to test this new OEFS, the ensemble mean is the best forecast if ranked using correlation, gross error, and root mean square error and has average performance when evaluated with the unpaired peak prediction accuracy. Ensemble averaging removes part of the unpredictable components of the physical and chemical processes involved in the ozone fate, resulting in a more skilful forecast when compared to any deterministic ensemble member. There is not one of the 12 individual forecasts that clearly outperforms the others on the basis of the four statistical parameters considered here. A lagged‐averaged OEFS is also tested as follows. The 12‐member OEFS is expanded to an 18‐member OEFS by adding the second day from the six 12‐km “yesterday” forecasts to the “today” ensemble forecast. The 18‐member ensemble does not improve the ensemble mean forecast skill. Neither correlation nor a relationship between ensemble spread and forecast error is evident.
Ozone ensemble forecasts: 2. A Kalman filter predictor bias correction
Authors: Delle Monache Luca , Nipen Thomas , Deng Xingxiu , Zhou Yongmei , Stull Roland
Published: March 2006

The Kalman filter (KF) is a recursive algorithm to estimate a signal from noisy measurements. In this study it is tested in predictor mode, to postprocess ozone forecasts to remove systematic errors. The recent past forecasts and observations are used by the KF to estimate the future bias. This bias correction is calculated separately for, and applied to, 12 different air quality (AQ) forecasts for the period 11–15 August 2004, over five monitoring stations in the Lower Fraser Valley, British Columbia, Canada, a population center in a complex coastal mountain setting. The 12 AQ forecasts are obtained by driving an AQ Model (CMAQ) with two mesoscale meteorological models (each run at two resolutions) and for three emission scenarios (Delle Monache et al., 2006). From the 12 KF AQ forecasts an ensemble mean is calculated (EK). This ensemble mean is also KF bias corrected, resulting in a high‐quality estimate (KEK) of the short‐term (1‐ to 2‐day) ozone forecast. The Kalman filter predictor bias‐corrected ensemble forecasts have better forecast skill than the raw forecasts for the locations and days used here. The corrected forecasts are improved for correlation, gross error, root mean square error, and unpaired peak prediction accuracy. KEK is the best and EK is the second best forecast overall when compared with the other 12 forecasts. The reason for the success of EK and KEK is that both the systematic and unsystematic errors are reduced, the first by Kalman filtering and the second by ensemble averaging.
Cluster analysis of planetary remote sensing spectral data
Authors: Marzo G. A. , Roush T. L. , Blanco A. , Fonti S. , Orofino V.
Published: March 2006

In this work, an innovative approach for remote sensing data analysis is presented. A statistical multivariate approach, applied to spectroscopic data, is able to reduce and explore the large amount of data collected during planetary missions. The multivariate statistical approach implemented is a cluster analysis method together with a criterium able to identify the natural number of clusters present in the spectral data set. An evaluation of the statistical analysis methods has been developed, implemented, and applied to analyze Mars thermal emission data. We find the statistical approach readily identifies spurious data. The resulting number of clusters provides ≥105 reduction in data volume. This allows a focusing of scientific interest onto a limited number of statistically significant groups. A comparison of the results of the statistical approach to previous expert analysis of Mars thermal emission data, for the Sinus Meridiani region where a hematite‐rich area of Mars has been previously detected, is provided. We find that several of the clusters reproduce the results of the expert analyses of the Sinus Meridiani hematite distribution. The current approach has the additional advantage of eliminating the time‐consuming techniques of atmospheric correction, when surface features are to be investigated.
Tectonic pressurization of aquifers in the formation of Mangala and Athabasca Valles, Mars
Authors: Hanna Jeffrey C. , Phillips Roger J.
Published: March 2006

Mangala and Athabasca Valles are the type examples of a distinct class of outflow channels that debouch directly from extensional tectonic features. We here demonstrate that the tectonic events responsible for the formation of the graben and fissures at the sources of the channels would have likely resulted in a near‐instantaneous pressurization of the surrounding aquifers. Subsequent drainage of the pressurized aquifers though the confining cryosphere to the surface along the tectonically generated faults and fissures would have produced the catastrophic floods responsible for forming the channels. The peak discharges and individual flood volumes would have been dependent upon the magnitude of the individual tectonic events at the source regions. We estimate that individual extensional tectonic events at the source regions of Mangala and Athabasca Valles would have resulted in flood volumes ranging from 3 to 300 km3 and peak discharges ranging from 105 to 106 m3 s−1. Our models further show that the entire extensional tectonic history of Athabasca Valles would have resulted in a total cumulative flood volume of 200–14,000 km3, whereas that at Mangala Valles would have resulted in a total flood volume of 3000–22,000 km3, both consistent with inferred flood volumes based on the geomorphology. Athabasca Valles in particular is of interest as it is the youngest of the outflow channels, demonstrating that this mechanism has brought substantial volumes of water to the surface in the present epoch.
Quantitative geomorphic modeling of Martian bedrock shorelines
Authors: Kraal Erin R. , Asphaug Erik , Moore Jeffrey M. , Lorenz Ralph D.
Published: March 2006

Multiple researchers have identified shoreline features, such as scarps, on Mars. These features occur in both paleocrater lake basins and the northern hemispheric basin. Here we use a simple numerical model to investigate the viability of forming Martian bedrock scarps via wind wave action. We use the Pierson‐Moskowitz equation modified for Martian gravity to generate wave fields under a variety of wind speeds and use those wave fields to drive a terrestrial bedrock shore erosion model modified for Martian conditions. Our results indicate that even with conservative assumptions for the key parameters of wind speed, slope, and substrate, it is difficult to form shoreline features of sufficient magnitude to be captured by spacecraft imaging. Under many combinations of reasonable initial conditions, no shoreline features are formed. In cases where shoreline features do develop, the largest equilibrium scarp height is ∼5 m, and the shorelines require nearly 2000 model years to form. In light of these results and the difficulty of maintaining warm, wet climates on Mars, it seems unlikely that the putative shoreline features identified in images are a result of water wave erosion, and alternative hypotheses, such as ice cover, should be entertained.
A simple index for Pi2 pulsations to nowcast substorms by Regional Warning Centre Canada
Authors: Lam H.‐L.
Published: March 2006

Substorm onsets and intensifications are accompanied by Pi2 magnetic pulsation bursts. Thus Pi2 would seem to be ideal for inferring the occurrence of substorm. However, the full potential of Pi2 pulsations as a proxy for substorms has not been fully exploited by the space weather community, although they are sometimes used by researchers to identify substorm onsets. To this end, a simple Pi2 index has been devised for stations in the auroral zone and subauroral zone in Canada on the basis of the log of the integrated power of the Pi2 spectrum, in analogy to the quasi‐logarithmic Kp or K indices. The Pi2 power spectrum necessarily contains a contribution by the substorm electrojet, as a power law relationship between Pi2 powers and X‐negative bay extremes found in this study indicates. The index is shown to detect distinct bay signatures of substorm events regionally around local midnight at Canadian latitudes and would thus compensate for the inadequacy of the global geomagnetic indices such as Kp. An automatic production of such a Pi2‐based substorm index, using near‐real‐time data from Canadian observatories, enables the Regional Warning Centre Canada of the International Space Environment Services to nowcast substorms in order to meet the demands of users for real‐time knowledge of nighttime localized extreme geomagnetic variability.
Analysis of a monsoon flood event in an ephemeral tributary and its downstream hydrologic effects
Authors: Vivoni Enrique R. , Bowman Robert S. , Wyckoff Robert L. , Jakubowski Ryan T. , Richards Kate E.
Published: March 2006

Despite existing observational networks, large‐scale flooding events in semiarid regions are poorly understood because of their infrequent occurrence and the lack of studies directed at quantifying their basic characteristics. Given the ephemeral nature of semiarid basins, large floods are critical events which can cause significant exchanges of water, sediment, and nutrients across the surface‐groundwater interface. Our major objective in this study is to quantify the meteorological characteristics, watershed runoff response, and surface‐groundwater interactions arising from a summer monsoon flood event in the Río Puerco and its downstream hydrologic effects in the Río Grande. Results indicate that only 3.6% of the storm rainfall resulted in tributary runoff which led to a propagating flood wave in the Río Grande. Along the main river reach we compute that 49% of the flood volume was lost to the shallow aquifer, with the remainder entering a downstream reservoir. Surface‐groundwater interactions were further tracked in a network of shallow wells, suggesting significant changes in groundwater level, ranging from 0.05 to 0.6 m, along and across the river. The results of this study demonstrate the widespread effects of large‐scale monsoon events in semiarid regions and serve as a basis for improved process understanding and modeling. On the basis of our observations we present a conceptual model of the generation, propagation, and attenuation of large floods in semiarid tributaries and main stem rivers during the North American monsoon. These linked processes have not been previously documented in a comprehensive manner in the American Southwest.
Bayesian analysis of input uncertainty in hydrological modeling: 1. Theory
Authors: Kavetski Dmitri , Kuczera George , Franks Stewart W.
Published: March 2006

Parameter estimation in rainfall‐runoff models is affected by uncertainties in the measured input/output data (typically, rainfall and runoff, respectively), as well as model error. Despite advances in data collection and model construction, we expect input uncertainty to be particularly significant (because of the high spatial and temporal variability of precipitation) and to remain considerable in the foreseeable future. Ignoring this uncertainty compromises hydrological modeling, potentially yielding biased and misleading results. This paper develops a Bayesian total error analysis methodology for hydrological models that allows (indeed, requires) the modeler to directly and transparently incorporate, test, and refine existing understanding of all sources of data uncertainty in a specific application, including both rainfall and runoff uncertainties. The methodology employs additional (latent) variables to filter out the input corruption given the model hypothesis and the observed data. In this study, the input uncertainty is assumed to be multiplicative Gaussian and independent for each storm, but the general framework allows alternative uncertainty models. Several ways of incorporating vague prior knowledge of input corruption are discussed, contrasting Gaussian and inverse gamma assumptions; the latter method avoids degeneracies in the objective function. Although the general methodology is computationally intensive because of the additional latent variables, a range of modern numerical methods, particularly Monte Carlo analysis combined with fast Newton‐type optimization methods and Hessian‐based covariance analysis, can be employed to obtain practical solutions.