bluuebunny/crossref_metadata_2025_split huggingface dataset:
South Atlantic divergent margin evolution: rift-border uplift and salt tectonics in the basins of SE Brazil
Authors: Mohriak W. , Nemčok M. , Enciso G. 
Published: January 2008

Abstract
The South Atlantic Ocean evolved after rupture of the São Francisco–Congo–Rio de la Plata–Kalahari cratonic landmass and the Late Proterozoic fold belts. Break-up in the South Atlantic realm developed diachronously: rifting started in the south (Argentina) during the Jurassic and progressed towards the equatorial segment. The central portion was controlled by a rift-resistant cratonic nucleus (the São Francisco–Congo craton) and as a result underwent development of narrow basins; parts controlled by Neoproterozoic fold belts developed wide basins. The final break-up of western Gondwana and the onset of plate divergence were marked by thick wedges of seaward-dipping reflectors, located near the incipient ocean-ridge spreading centre that had already been formed by the time Aptian evaporites were deposited. Subsequently, a few episodes of intraplate tectonic and magmatic activity affected the Santos, Campos and Espírito Santo basins.
Post-break up development of the offshore basins was affected by gravity gliding over the Aptian evaporites. Continental uplift may be invoked as the main cause of salt mobilization, generating prograding clastic wedges that thickened basin-wards and produced a loading effect on the salt basin. Coupled with onshore erosional unloading and the effects of the gravity gliding, this probably resulted in further flexural uplift of the continental margin.
Restoring Pan-African-Brasiliano connections: more Gondwana control, less Trans-Atlantic corruption
Authors: de Wit M. J. , Stankiewicz J. , Reeves C. 
Published: January 2008

Abstract
The concept of South America and Africa as rigid continents during the formation, growth and motion of their respective plates has frustrated reconstruction of a tight, geologically economic fit between these two fragments in their Gondwana framework. We recognize that (1) internal strains released during and following Gondwana break-up have distorted their actual shapes within Gondwana and (2) these two continents comprise mosaics of smaller microblocks, or platelets, of relatively undistorted Precambrian terrains that experienced modest, episodic relative motions along rift zones that separate them. This permits a fresh approach to quantitative reconstructions of palaeo-continents. Former geological ties forged at the time of Gondwana amalgamation, now exposed at the continental margins of the South Atlantic as piercing points, provide robust anchors for new paleo-cartographic experiments. We present two new tectonic maps of the Brasiliano and Pan-African structures of West Gondwana on which we identify ten piercing points that, if re-joined simultaneously, could facilitate quantification of a well-substantiated Gondwana fit and help retrace the evolution of its continental margins with greater accuracy than has been achieved until now. This has significant bearing on understanding the origin and evolution of passive continental margins, and the geodynamics of Gondwana break-up.
Geology of the northern Borborema Province, NE Brazil and its correlation with Nigeria, NW Africa
Authors: Arthaud M. H. , Caby R. , Fuck R. A. , Dantas E. L. , Parente C. V. 
Published: January 2008

Abstract

The Borborema and Benin–Nigeria provinces of NE Brazil and NW Africa, respectively, are key areas in the amalgamation of West Gondwana by continental collision during the Brasiliano/Pan-African orogenies. Both are underlain by complex basement: Nigeria has
c.
3.05 Ga Archaean crust but no known Palaeoproterozoic rocks >2.0 Ga; in NE Brazil, 2.6–3.5 Ga Archaean rocks form small cores within Palaeoproterozoic gneiss terrains affected by plutonism at
c.
2.17 Ga. Both regions exhibit Late Palaeoproterozoic (
c.
1.8 Ga) rift-related magmatism and metasedimentary sequences overlying the basement. The Seridó Group of NE Brazil (<0.65 Ga) is similar to the Igarra Sequence in SW Nigeria. The Ceará Group, which may date back to
c.
0.85 Ga, is a passive margin deposit on crust thinned during initiation of an oceanic domain. In both provinces, basement and sedimentary cover were involved in tangential tectonics that resulted in crust-thickening by nappe-stacking associated with closure of this ocean. Frontal collision between
c.
0.66 and 0.60 Ga later evolved to an oblique collision, generating north–south continental strike-slip shear zones at
c.
0.59 Ga. In NE Brazil, the main Pan-African suture is probably buried beneath the Parnaíba Basin. The Transbrasiliano Lineament, interpreted as the prolongation of the Kandi–4°50 Lineament in Hoggar, may represent a cryptic suture.
Proterozoic links between the Borborema Province, NE Brazil, and the Central African Fold Belt
Authors: van Schmus W. R. , Oliveira E. P. , da Silva Filho A. F. , Toteu S. F. , Penaye J. , Guimarães I. P. 
Published: January 2008

Abstract

The Congo (CC) and the São Francisco (SFC) cratons were joined at about 2.05 Ga; northern parts of Palaeoproterozoic basement subsequently underwent extension at about 1 Ga, forming intracratonic basins. Neoproterozoic metasedimentary rocks in these basins yield detrital zircons as young as 630 Ma. The Brasiliano and Pan-African (
c.
620–580 Ma) assembly of West Gondwana extensively altered this system. The Sergipano domain occurs north of the SFC, and the comparable Yaoundé domain occurs north of the CC. Crust north of the Sergipano domain comprises the Pernambuco–Alagoas (PEAL) domain. The NE–SW-striking Tcholliré–Banyo fault in Cameroon may extend southwestwards between the PEAL and Sergipano domains, defining northern limits of abundant SFC/CC basement. The Adamawa–Yadé domain in Africa does not appear to extend into Brazil. The Transverse domain of Brazil is a collage of Palaeoproterozoic crustal blocks, the 1.0 Ga Cariris Velhos orogen (CVO), late Neoproterozoic basins, and Brasiliano granites. The CVO extends ENE for more than 700 km in Brazil, but eastern continuation into Africa has not been identified. North of the Transverse domain contiguous
c.
2.15 Ga gneisses comprise basement of Rio Grande do Norte and Ceará domains, which continue eastwards into western Nigeria and western Sahara.
São Luís Craton and Gurupi Belt (Brazil): possible links with the West African Craton and surrounding Pan-African belts
Authors: Klein E. L. , Moura C. A. V. 
Published: January 2008

Abstract
The São Luís Craton and the Palaeoproterozoic basement rocks of the Neoproterozoic Gurupi Belt in northern Brazil are part of an orogen having an early accretionary phase at 2240–2150 Ma and a late collisional phase at 2080±20 Ma. Geological, geochronological and isotopic evidence, along with palaeogeographic reconstructions, strongly suggest that these Brazilian terrains were contiguous with the West African Craton in Palaeoproterozoic times, and that this landmass apparently survived subsequent continental break-up until its incorporation in Rodinia.

The Gurupi Belt is an orogen developed in the southern margin of the West African–São Luís Craton at
c
. 750–550 Ma, after the break up of Rodinia. Factors such as present-day and possible past geographical positions, the timing of a few well-characterized events, the structural polarity and internal structure of the belt, in addition to other indirect evidence, all favour correlation between the Gurupi Belt and other Brasiliano/Pan-African belts, especially the Médio Coreaú domain of the Borborema Province and the Trans-Saharan Belt of Africa, despite the lack of proven physical links between them. These Neoproterozoic belts are part of the branched system of orogens associated with amalgamation of the Amazonian, West Africa–São Luís, São Francisco and other cratons and minor continental blocks into the West Gondwana supercontinent.
Similarities and differences between the Brazilian and African counterparts of the Neoproterozoic Araçuaí-West Congo orogen
Authors: Pedrosa-Soares A. C. , Alkmim F. F. , Tack L. , Noce C. M. , Babinski M. , Silva L. C. , Martins-Neto M. A. 
Published: January 2008

Abstract
The Araçuaí–West Congo orogen encompasses orogenic domains located to the SE of the São Francisco Craton in Brazil, and to the SW of the Congo Craton in Africa. From the opening of the precursor basin to the last orogenic processes, the evolution of the orogen lasted from the very beginning of the Neoproterozoic up to the Cambrian–Ordovician boundary. After the spreading of the South Atlantic Ocean in Cretaceous time, the Araçuaí–West Congo orogen was split into two quite different but complementary counterparts. The Brazilian side (Araçuaí orogen) inherited two thirds of the whole orogenic edifice, including all the Neoproterozoic ophiolite slivers, the entire magmatic arc and syn-collisional to post-collisional magmatism, and the suture zone. The African counterpart (West Congo Belt), a fold–thrust belt free of Neoproterozoic ophiolite and Pan-African orogenic magmatism, inherited the thick pile of bimodal volcanic rocks of the Early Tonian rift stage, implying that the precursor basin was an asymmetrical rift with the thermal–magmatic axis located in the West Congo Belt. Both counterparts of the Araçuaí–West Congo orogen include Neoproterozoic glaciogenic deposits, allowing tentative lithostratigraphic correlations, but identification of the ice ages remains uncertain because the lack of sufficient well-constrained geochronological data.
Kinematic and Moisture Characteristics of a Nonprecipitating Cold Front Observed during IHOP. Part I: Across-Front Structures
Authors: Friedrich Katja , Kingsmill David E. , Flamant Cyrille , Murphey Hanne V. , Wakimoto Roger M. 
Published: January 2008

Abstract
A wide array of ground-based and airborne instrumentation is used to examine the kinematic and moisture characteristics of a nonprecipitating cold front observed in west-central Kansas on 10 June 2002 during the International H2O Project (IHOP). This study, the first of two parts, is focused on describing structures in the across-front dimension. Coarsely resolved observations from the operational network and dropsondes deployed over a 200-km distance centered on the front are combined with higher-resolution observations from in situ sensors, Doppler radars, a microwave radiometer, and a differential absorption lidar that were collected across a ∼40-km swath that straddled a ∼100-km segment of the front.
The northeast–southwest-oriented cold front moved toward the southeast at ∼8–10 m s−1 during the morning hours, but its motion slowed to less than 1 m s−1 in the afternoon. In the early afternoon, the cold front separated cool air with a northerly component flow of 2–4 m s−1 from a 10-km-wide band of hot, dry air with 5 m s−1 winds out of the south-southwest. The average updraft at the frontal interface was ∼0.5 m s−1 and slightly tilted back toward the cool air. A dryline was located to the southeast of the front, separating the hot, dry air mass from a warm, moist air mass composed of 10 m s−1 southerly winds. Later in the afternoon, the warm, moister air moved farther to the northwest, approaching the cold front. The dryline was still well observed in the southwestern part of the observational domain while it vanished almost completely in the northeastern part. Low-level convergence (∼1 × 10−3 s−1), vertical vorticity (∼0.5 × 10−3 s−1), and vertical velocity (∼1 m s−1) increased. The strong stable layer located at ∼2.0–2.5 km MSL weakened in the course of the afternoon, providing a basis for the development of isolated thunderstorms. The applicability of gravity current theory to the cold front was studied. There was evidence of certain gravity current characteristics, such as Froude numbers between 0.7 and 1.4, a pronounced feeder flow toward the leading edge, and a rotor circulation. Other characteristics, such as a sharp change in pressure and lobe and cleft structures, remain uncertain due to the temporally and spatially variable nature of the phenomenon and the coarse resolution of the measurements.
A New Approximate Solution of the Optimal Nonlinear Filter for Data Assimilation in Meteorology and Oceanography
Authors: Hoteit I. , Pham D-T. , Triantafyllou G. , Korres G. 
Published: January 2008

Abstract
This paper introduces a new approximate solution of the optimal nonlinear filter suitable for nonlinear oceanic and atmospheric data assimilation problems. The method is based on a local linearization in a low-rank kernel representation of the state’s probability density function. In the resulting low-rank kernel particle Kalman (LRKPK) filter, the standard (weight type) particle filter correction is complemented by a Kalman-type correction for each particle using the covariance matrix of the kernel mixture. The LRKPK filter’s solution is then obtained as the weighted average of several low-rank square root Kalman filters operating in parallel. The Kalman-type correction reduces the risk of ensemble degeneracy, which enables the filter to efficiently operate with fewer particles than the particle filter. Combined with the low-rank approximation, it allows the implementation of the LRKPK filter with high-dimensional oceanic and atmospheric systems. The new filter is described and its relevance demonstrated through applications with the simple Lorenz model and a realistic configuration of the Princeton Ocean Model (POM) in the Mediterranean Sea.
The ECPC Coupled Prediction Model
Authors: Yulaeva E. , Kanamitsu M. , Roads J. 
Published: January 2008

Abstract
This paper presents a new Experimental Climate Prediction Center (ECPC) Coupled Prediction Model (ECPM). The ECPM includes the Jet Propulsion Laboratory (JPL) version of the Massachusetts Institute of Technology (MIT) ocean model coupled to the ECPC version of the National Centers for Environmental Prediction (NCEP) Atmospheric Global Spectral Model (GSM). The adjoint and forward versions of the MIT model forced with the NCEP atmospheric analyses are routinely used at JPL for ocean state assimilation. An earlier version of the GSM was used for the NCEP–Department of Energy reanalysis-2 project and for operational seasonal forecasts at NCEP. The ECPM climatology and internal variability derived from a 56-yr-long coupled integration are compared with the observations and reanalysis data. Though the ECPM exhibits climatological biases, these biases are relatively small and comparable to the systematic errors produced by other well-known coupled models, including the recent NCEP Climate Forecast System. The internal variability of the model resembles the observations. ECPM simulates both seasonal and interannual variability in the tropical Pacific reasonably well. The model has good skill in reproducing the mechanism of ENSO evolution as well as ENSO teleconnection patterns (including the Indian monsoon–ENSO relationship). The skill of the ECPM in predicting 1994–2006 SST anomalies over the Niño-3.4 region is shown to be comparable to other coupled models. These retrospective forecasts were used for deriving a model climatology for real-time seasonal forecasts that are currently produced and displayed at ECPC.
Impact of the Assimilation of CHAMP Refractivity Profiles on Environment Canada Global Forecasts
Authors: Aparicio Josep M. , Deblonde Godelieve 
Published: January 2008

Abstract
The data assimilation system of Environment Canada (EC) is adapted to accept GPS radio occultation (GPSRO) data. Observations of this type are available with extensive coverage from several satellites. In this study, experiments are performed to compare the skill of EC’s three-dimensional variational data assimilation (3DVAR) system (including all data normally assimilated operationally), with and without the addition of radio occultation refractivity data from the Challenging Minisatellite Payload for Geophysical Research (CHAMP). These data were not available at the time studied as near-real-time (NRT) observations. However, data from this and other radio occultation missions are now available as NRT data, and the conditions (latency, reliability) are improving. It is expected that NRT GPSRO data from a number of satellite missions will continue to be available through the following years. The results of the assimilation tests are evaluated against the following three data types: radiosondes (temperature and dewpoint depression), satellite brightness temperatures (from the Advanced Microwave Sounding Unit-A), and GPS radio occultation refractivity profiles. For the 6-h forecasts, the differences between GPSRO observations and forecasts (O − F) are significantly reduced in the experiment that assimilates the GPSRO data. This reduction increases as the experiment proceeds in time, and stabilizes after a transient period of approximately 2 weeks, suggesting that the addition of GPSRO data to the assimilation system has a beneficial, persisting, and cumulative effect. This effect is more pronounced in the stratosphere than in the troposphere. In the stratosphere, the standard deviation of GPSRO (O − F) of the experiment that assimilates GPSRO decreases after the initial transient period by approximately 10%. This improvement can best be observed in the southern stratosphere where reductions of the order of 30% are common. This shows that, as a globally distributed and vertically well-resolved source of data, the GPSRO observations are not only useful for assimilation, but also as a tool to quantify the forecast skill of the assimilation system. Comparisons with radiometer and radiosonde data confirm the positive impact in these geographical areas. Longer-range forecasts (up to 6 days) also show a positive impact with similar geographical and altitude distribution.
A Dynamical Investigation of the May 2004 McMurdo Antarctica Severe Wind Event Using AMPS*
Authors: Steinhoff Daniel F. , Bromwich David H. , Lambertson Michelle , Knuth Shelley L. , Lazzara Matthew A. 
Published: January 2008

Abstract
On 15–16 May 2004 a severe windstorm struck McMurdo, Antarctica. The Antarctic Mesoscale Prediction System (AMPS) is used, along with available observations, to analyze the storm. A synoptic-scale cyclone weakens as it propagates across the Ross Ice Shelf toward McMurdo. Flow associated with the cyclone initiates a barrier jet along the Transantarctic Mountains. Forcing terms from the horizontal equations of motion are computed in the barrier wind to show that the local time tendency and momentum advection terms are key components of the force balance. The barrier jet interacts with a preexisting near-surface radiation inversion over the Ross Ice Shelf to set up conditions favorable for the development of large-amplitude mountain waves, leading to a downslope windstorm in the Ross Island area. Hydraulic theory can explain the structure of the downslope windstorms, with amplification of the mountain waves possibly caused by wave-breaking events. The underestimation of AMPS wind speed at McMurdo is caused by the misplacement of a hydraulic jump downstream of the downslope windstorms. The dynamics associated with the cyclone, barrier jet, and downslope windstorms are analyzed to determine the role of each in development of the severe winds.
Numerical Study of the Local Downslope Wind “Hirodo-Kaze” in Japan
Authors: Fudeyasu Hironori , Kuwagata Tsuneo , Ohashi Yukitaka , Suzuki Shin-ichi , Kiyohara Yasutomo , Hozumi Yu 
Published: January 2008

Abstract
The “Hirodo-kaze,” a local strong wind accompanying the downslope winds in Japan, is examined using a mesoscale numerical model. The model successfully reproduces the major features of the observed Hirodo-kaze that occurred in association with Typhoon Pabuk. During the Hirodo-kaze, the severe downslope winds in the transitional flow develop in the lower troposphere below the mean-state critical layer. The Hirodo-kaze is closely linked to the strong wind region accompanying the severe downslope winds. After the cessation of the Hirodo-kaze, distinct mountain waves dominate in the lower troposphere where the Scorer parameter l2 decreases with height. The region of strong wind retreats windward as the Hirodo-kaze ceases. Temporal changes in the characteristics of mountain waves in the lee of Mt. Nagi are primarily attributed to the changes in the large-scale environmental winds due to the movement of the intense cyclone.
Environmental conditions favorable for the occurrence of the Hirodo-kaze include strong northerlies in the lower troposphere overlain by southerlies in the middle troposphere. The intense cyclone that moves over the sea southwest of the Kii peninsula creates favorable environmental conditions that support the occurrence of the Hirodo-kaze.
Numerical Simulations of the Microphysics and Electrification of the Weakly Electrified 9 February 1993 TOGA COARE Squall Line: Comparisons with Observations
Authors: Fierro Alexandre O. , Leslie Lance M. , Mansell Edward R. , Straka Jerry M. 
Published: January 2008

Abstract
A cloud scale model with a 12-class bulk microphysics scheme, including 10 ice phases and a 3D lightning parameterization, was used to investigate the electrical properties of a well-documented tropical squall line from the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE). Consistent with observations, the simulated maximum updraft speeds across the squall line seldom exceeded 10 m s−1, which was expected given the relatively shallow 30-dBZ echo tops that rarely extended above the top of the mixed-phase layer (−20°C isotherm). Enhanced warm rain processes caused most of the liquid water to precipitate near the gust front at lower levels (below 4 km AGL), which accounted for the small amounts of graupel and cloud water content present in the mixed-phase region and, consequently, for generally weak charging and electrification.
Most of the charge present in the squall line was generated within a few storm cells just behind the leading edge of the gust front that had sufficiently strong updraft speeds near the melting level to produce moderate values of graupel mixing ratio (&gt;0.5 g kg−1). In contrast, the trailing stratiform region at the back of the line, which was mainly composed of ice crystals and snow particles, contained only weak net charge densities (&lt;0.03 nC m−3). The spatial collocation of regions characterized by charge densities exceeding 0.01 nC m−3 and noninductive (NI) charging rates greater than 0.1 pC m−3 s−1 in this stratiform region suggests that NI charging is a plausible source for the majority of this charge, which was confined to discrete regions having small amounts of graupel (approximately 0.1–0.3 g kg−1) and cloud water content (CWC; ∼0.1 g m−3).
The simulated weak updraft speeds and shallow echo tops resulted in a system exhibiting little overall total lightning activity. Although the 5-min average intracloud (IC) flash rate rarely exceeded 10 flashes per minute and only 3 negative cloud-to-ground (−CG) lightning flashes were produced during the entire 4 h and 30 min of simulation, this still was more electrical activity than observed. This tendency for the model to generate more lightning flashes than observed remained when the inductive charging mechanism was turned off, which reduced the total amount of simulated flashes by about 43%. The three CG flashes and the great majority of the IC flashes occurred within the strongest cells located in the mature zone, which exhibited a normal tripole charge structure.