bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Convective Transport and Parameter Sensitivity in a Single Column Version of the Goddard Earth Observation System, Version 5, General Circulation Model
Authors: Ott L. E. , Bacmeister J. , Pawson S. , Pickering K. , Stenchikov G. , Suarez M. , Huntrieser H. , Loewenstein M. , Lopez J. , Xueref-Remy I. 
Published: July 2008

Abstract
Convection strongly influences the distribution of atmospheric trace gases. General circulation models (GCMs) use convective mass fluxes calculated by parameterizations to transport gases, but the results are difficult to compare with trace gas observations because of differences in scale. The high resolution of cloud-resolving models (CRMs) facilitates direct comparison with aircraft observations. Averaged over a sufficient area, CRM results yield a validated product directly comparable to output from a single global model grid column. This study presents comparisons of vertical profiles of convective mass flux and trace gas mixing ratios derived from CRM and single column model (SCM) simulations of storms observed during three field campaigns. In all three cases, SCM simulations underpredicted convective mass flux relative to CRM simulations. As a result, the SCM simulations produced lower trace gas mixing ratios in the upper troposphere in two of the three storms than did the CRM simulations.
The impact of parameter sensitivity in the moist physics schemes employed in the SCM has also been examined. Statistical techniques identified the most significant parameters influencing convective transport. Convective mass fluxes are shown to be strongly dependent on chosen parameter values. Results show that altered parameter settings can substantially improve the comparison between SCM and CRM convective mass flux. Upper tropospheric trace gas mixing ratios were also improved in two storms. In the remaining storm, the SCM representation of CO2 was not improved because of differences in entrainment and detrainment levels in the CRM and SCM simulations.
Climate Regime Variability for Past and Present Time Slices Simulated by the Fast Ocean Atmosphere Model
Authors: Handorf Dörthe , Dethloff Klaus , Marshall Andrew G. , Lynch Amanda 
Published: July 2008

Abstract
This paper presents an analysis of Northern Hemisphere climate regime variability for three different time slices, simulated by the Fast Ocean Atmosphere Model (FOAM). The three time slices are composed of present-day conditions, the mid-Holocene, and the Last Glacial Maximum (LGM). Climate regimes have been determined by analyzing the structure of a spherical probability density function in a low-dimensional state space spanned by the three leading empirical orthogonal functions. This study confirms the ability of the FOAM medium-resolution climate model to reproduce low-frequency climate variability in the form of regime-like behavior. Three to four regimes have been detected for each time slice. Compared with present-day conditions, new climate regimes appeared for the LGM. For the mid-Holocene, which had slightly different boundary conditions and external forcings than the present-day simulation, the frequency of occurrence of the regimes was altered while only slight changes were found in the structure of some regimes.
Predictors of Tropical Cyclone Numbers and Extreme Hurricane Intensities over the North Atlantic Using Generalized Additive and Linear Models
Authors: Mestre Olivier , Hallegatte Stéphane 
Published: July 2008

AbstractFluctuations of the annual number of tropical cyclones over the North Atlantic and of the energy dissipated by the most intense hurricane of a season are related to a variety of predictors [global temperature, SST and detrended SST, North Atlantic Oscillation (NAO), Southern Oscillation index (SOI)] using generalized additive and linear models. This study demonstrates that SST and SOI are predictors of interest. The SST is found to influence positively the annual number of tropical cyclones and the intensity of the most intense hurricanes. The use of specific additive models reveals nonlinearity in the responses to SOI that has to be taken into account using changepoint models. The long-term trend in SST is found to influence the annual number of tropical cyclones but does not add information for the prediction of the most intense hurricane intensity.
Warming of the Upper Equatorial Indian Ocean and Changes in the Heat Budget (1960–99)
Authors: Alory Gaël , Meyers Gary 
Published: July 2008

Abstract
In the equatorial Indian Ocean, sea surface has warmed by 0.5°–1°C over the 1960–99 period, while waters have cooled at thermocline depth and the net atmospheric heat flux has decreased. Among a set of twentieth-century climate simulations from 12 coupled models, the Centre National de Recherches Météorologiques Coupled Global Climate Model version 3 (CNRM-CM3) reproduces key observed features of these changes. It is used to investigate changes in the heat budget of the upper equatorial Indian Ocean and identify mechanisms responsible for the warming. By comparing twentieth-century and control simulations, significant shifts in the mean balance of the heat budget between the preindustrial and the 1960–99 periods can be identified. The main cause of the surface warming is a decrease in the upwelling-related oceanic cooling. It occurs in the thermocline dome region because of a slowdown of the wind-driven Ekman pumping. The observed decrease in net heat flux is a negative feedback driven by evaporation, which is enhanced by the equatorial warming and associated strengthening of trade winds.
Improving the Numerical Solution of Soil Moisture–Based Richards Equation for Land Models with a Deep or Shallow Water Table
Authors: Zeng Xubin , Decker Mark 
Published: July 2008

Abstract
The soil moisture–based Richards equation is widely used in land models for weather and climate studies, but its numerical solution using the mass-conservative scheme in the Community Land Model is found to be deficient when the water table is within the model domain. Furthermore, these deficiencies cannot be reduced by using a smaller grid spacing. The numerical errors are much smaller when the water table is below the model domain. These deficiencies were overlooked in the past, most likely because of the more dominant influence of the free drainage bottom boundary condition used by many land models. They are fixed here by explicitly subtracting the hydrostatic equilibrium soil moisture distribution from the Richards equation. This equilibrium distribution can be derived at each time step from a constant hydraulic (i.e., capillary plus gravitational) potential above the water table, representing a steady-state solution of the Richards equation. Furthermore, because the free drainage condition has serious deficiencies, a new bottom boundary condition based on the equilibrium soil moisture distribution at each time step is proposed that also provides an effective and direct coupling between groundwater and surface water.
On the Interaction of Time-Variable Flows with a Shelfbreak Canyon
Authors: Kämpf Jochen 
Published: July 2008

Abstract
Process-oriented hydrodynamic modeling is employed to study the interaction of along-slope flows with an idealized submarine shelfbreak canyon. The model is forced via prescription of oscillatory flows superposed on steady background flows of various strength and direction. Findings suggest that purely oscillatory flow does not produce significant net onshore transport of dense water. It is rather the steady component of the flow that creates substantial up-canyon flows of ∼0.05 Sv (1 Sv = 106 m3 s−1) in volume transport. This takes place exclusively for flows running on average against the propagation direction of coastal Kelvin waves, whereas flows of the opposite direction operate to suppress cross-shelf density fluxes.
Atmospheric Control on the Thermohaline Circulation
Authors: Czaja Arnaud 
Published: July 2008

Abstract
In an attempt to elucidate the role of atmospheric and oceanic processes in setting a vigorous ocean overturning circulation in the North Atlantic but not in the North Pacific, a comparison of the observed atmospheric circulation and net surface freshwater fluxes over the North Atlantic and Pacific basins is conducted. It is proposed that the more erratic meridional displacements of the atmospheric jet stream over the North Atlantic sector is instrumental in maintaining high surface salinities in its subpolar gyre. In addition, it is suggested that the spatial pattern of the net freshwater flux at the sea surface favors higher subpolar Atlantic salinity, because the geographical line separating net precipitation from net evaporation is found well south of the time-mean gyre separation in the North Pacific, whereas the two lines tend to coincide in the North Atlantic. Numerical experiments with an idealized two-gyre system confirm that these differences impact the salinity budget of the subpolar gyre.
Further analysis of a coupled climate model in which the Atlantic meridional overturning cell has been artificially weakened suggests that the more erratic jet fluctuations in the Atlantic and the shift of the zero [net evaporation minus precipitation (E − P)] line are likely explained by features independent of the state of the thermohaline circulation. It is thus proposed that the atmospheric circulation helps “locking” high surface salinities and an active coupling between upper and deep ocean layers in the North Atlantic rather than in the North Pacific basin.
Orthogonal Channel Coding for Simultaneous Co- and Cross-Polarization Measurements
Authors: Chandrasekar V. , Bharadwaj Nitin 
Published: July 2008

Abstract
Dual-polarization weather radars typically measure the radar reflectivity at more than one polarization state for transmission and reception. Historically, dual-polarization radars have been operated at copolar and cross-polar states defined with respect to the transmit polarization states. Recently, based on the improved understanding of the propagation properties of electromagnetic waves in precipitation media, the simultaneous transmit and receive (STAR) mode has become common to simplify the hardware. In the STAR mode of operation, horizontal and vertical polarization states are transmitted simultaneously and samples of both horizontal and vertical copolar returns are obtained. A drawback of the current implementation of STAR mode is its inability to measure parameters obtained from cross-polar signals such as linear depolarization ratio (LDR). In this paper, a technique to obtain cross-polar signals with STAR mode waveform is presented. In this technique, the horizontally and vertically polarized transmit waveforms are coded with orthogonal phase sequences. The performance of the phase-coded waveform is determined by the properties of the phase codes. This orthogonal phase coding technique is implemented in the Colorado State University–University of Chicago–Illinois State Water Survey (CSU–CHILL) radar. This paper outlines the methodology and presents the performance of the cross-polar and copolar parameter estimation based on the simulation as well as data collected from the CSU–CHILL radar.
Nature of the Mesoscale Boundary Layer Height and Water Vapor Variability Observed 14 June 2002 during the IHOP_2002 Campaign
Authors: Couvreux F. , Guichard F. , Austin P. H. , Chen F. 
Published: July 2008

Abstract
Mesoscale water vapor heterogeneities in the boundary layer are studied within the context of the International H2O Project (IHOP_2002). A significant portion of the water vapor variability in the IHOP_2002 occurs at the mesoscale, with the spatial pattern and the magnitude of the variability changing from day to day. On 14 June 2002, an atypical mesoscale gradient is observed, which is the reverse of the climatological gradient over this area. The factors causing this water vapor variability are investigated using complementary platforms (e.g., aircraft, satellite, and in situ) and models. The impact of surface flux heterogeneities and atmospheric variability are evaluated separately using a 1D boundary layer model, which uses surface fluxes from the High-Resolution Land Data Assimilation System (HRLDAS) and early-morning atmospheric temperature and moisture profiles from a mesoscale model. This methodology, based on the use of robust modeling components, allows the authors to tackle the question of the nature of the observed mesoscale variability. The impact of horizontal advection is inferred from a careful analysis of available observations. By isolating the individual contributions to mesoscale water vapor variability, it is shown that the observed moisture variability cannot be explained by a single process, but rather involves a combination of different factors: the boundary layer height, which is strongly controlled by the surface buoyancy flux, the surface latent heat flux, the early-morning heterogeneity of the atmosphere, horizontal advection, and the radiative impact of clouds.
A Simplified Dynamical System for Tropical Cyclone Intensity Prediction
Authors: DeMaria Mark 
Published: July 2008

Abstract
A simplified dynamical system for tropical cyclone intensity prediction based on a logistic growth equation (LGE) is developed. The time tendency of the maximum sustained surface winds is proportional to the sum of two terms: a growth term and a term that limits the maximum wind to an upper bound. The maximum wind evolution over land is determined by an empirical inland wind decay formula. The LGE contains four free parameters, which are the time-dependent growth rate and maximum potential intensity (MPI), and two constants that determine how quickly the intensity relaxes toward the MPI. The MPI is estimated from an empirical formula as a function of sea surface temperature and storm translational speed. The adjoint of the LGE provides a method for finding the other three free parameters to make the predictions as close as possible to the National Hurricane Center best-track intensities. The growth rate is assumed to be a linear function of the vertical shear (S), a convective instability parameter (C) determined from an entraining plume, and their product, where both S and C use global model fields as input. This assumption reduces the parameter estimation problem to the selection of six constants. Results show that the LGE optimized for the full life cycle of individual storms can very accurately simulate the intensity variations out to as long as 15 days. For intensity prediction, single values of the six constants are found by fitting the model to more than 2400 Atlantic forecasts from 2001 to 2006. Results show that the observed intensity variations can be fit more accurately with the LGE than with the linear Statistical Hurricane Intensity Prediction Scheme (SHIPS) formulation, and with a much smaller number of constants. Results also show that LGE model solution (and some properties of real storms) can be explained by the evolution in the two-dimensional S–C phase space. Forecast and other applications of the LGE model are discussed.
Evaluation of Cloud Physical Properties of ECMWF Analysis and Re-Analysis (ERA) against CERES Tropical Deep Convective Cloud Object Observations
Authors: Xu Kuan-Man 
Published: July 2008

Abstract
This study presents an approach that converts the vertical profiles of grid-averaged cloud properties from large-scale models to probability density functions (pdfs) of subgrid-cell cloud physical properties measured at satellite footprints. Cloud physical and radiative properties, rather than just cloud and precipitation occurrences, of assimilated cloud systems by the European Centre for Medium-Range Weather Forecasts (ECMWF) operational analysis (EOA) and 40-yr ECMWF Re-Analysis (ERA-40) are validated against those obtained from Earth Observing System satellite cloud object data for the January–August 1998 and March 2000 periods. These properties include the ice water path (IWP), cloud-top height and temperature, cloud optical depth, and solar and infrared radiative fluxes. Each cloud object, a contiguous region with similar cloud physical properties, is temporally and spatially matched with EOA and ERA-40 data. Results indicate that most pdfs of EOA and ERA-40 cloud physical and radiative properties agree with those of satellite observations of the tropical deep convective cloud object type for the January–August 1998 period. There are, however, significant discrepancies in selected ranges of the cloud property pdfs such as the upper range of EOA cloud-top height. A major discrepancy is that the dependence of the pdfs on the cloud object size for both EOA and ERA-40 is not as strong as in the observations. Modifications to the cloud parameterization in ECMWF that occurred in October 1999 eliminate the clouds near the tropopause but shift power of the pdf to lower cloud-top heights and greatly reduce the ranges of IWP and cloud optical depth pdfs. These features persist in ERA-40 due to the use of the same cloud parameterizations. The less sophisticated data assimilation technique and the lack of snow water content information in ERA-40, not the larger horizontal grid spacing, are also responsible for the disagreements with observed pdfs of cloud physical properties, although the detection rates of cloud object occurrence are improved for small-size categories. A possible improvement to the convective parameterization is to introduce a stronger dependence of updraft penetration heights on grid-cell dynamics.
Moyamoya syndrome associated with systemic lupus erythematosus
Authors: Jeong HC , Kim YJ , Yoon W , Joo SP , Lee SS , Park YW 
Published: July 2008

Abstract Moyamoya disease is a rare, progressive cerebrovascular disorder that is characterized by a stenosis or occlusion of the bilateral internal carotid arteries and the development of collateral vessels. Transient ischemic attacks or seizures are the usual presentation of moyamoya disease in children, whereas cerebral hemorrhage is the most common symptom in adults. We report an 18-year-old female patient with active lupus nephritis who presented with the sudden onset of left hemiparesis. Brain magnetic resonance imaging showed acute infarctions in the right basal ganglia and subcortical white matter of the right frontal lobe. Cerebral angiography showed the stenosis of the bilateral internal carotid arteries with rich basal collateral vessels (moyamoya vessels). There was no evidence of atherosclerosis or antiphospholipid syndrome. Glucocorticoid therapy was used to control the systemic lupus erythematosus. Prophylactic bypass surgery was performed to prevent recurrent ischemic attacks. This case report shows that an underlying cerebrovascular lesion of moyamoya vessels in a patient with systemic lupus erythematosus is susceptible to cerebrovascular accidents.
Rituximab treatment of pulmonary arterial hypertension associated with systemic lupus erythematosus: a case report
Authors: Hennigan S , Channick RN , Silverman GJ 
Published: July 2008

Abstract Pulmonary hypertension is a common but underdiagnosed complication of systemic lupus erythematosus, which can be associated with significant morbidity and early mortality. Although often associated with anti-phospholipid antibodies, the etiology remains poorly understood. In case reports and small open trials, the anti-CD20, B-cell targeted therapeutic antibody, rituximab, has been reported to provide benefits for systemic lupus erythematosus patients with glomerulonephritis, anti-phospholipid antibody syndrome, vasculitis, arthritis, and refractory skin disease. However, the outcome of rituximab treatment of pulmonary arterial hypertension associated with systemic lupus erythematosus has not been described. We, therefore, present a case of a young systemic lupus erythematosus patient with early onset of pulmonary arterial hypertension during the disease course, refractory to multiple treatment modalities, who had significant improvement with rituximab therapy.
Childhood systemic lupus erythematosus in Sultanate of Oman: demographics and clinical analysis
Authors: Abdwani R , Rizvi SG , El-Nour I 
Published: July 2008

There is a worldwide variation in the incidence of childhood manifestation of systemic lupus erythematosus, which may be related to environmental, genetic and geographical factors. The aim of the study is to describe for the first time the clinical and immunological characteristics of childhood onset systemic lupus erythematosus at diagnosis in the Sultanate of Oman. We retrospectively reviewed the records of 50 children with systemic lupus erythematosus fulfilling the American College of Rheumatology criteria between 1990 and 2006. There were 42 girls and eight boys. The mean age of disease onset was low at 8.6 years (SD 3.1). The female:male ratio was 5.3:1. The most frequent clinical manifestations at initial diagnosis were: articular (76%), cutaneous (70%), haematological (68%) and renal (64%) dominated by class IV nephritis, pulmonary (26%), neuropsychiatric (18%) and cardiac (10%). A positive antinuclear antibody (>1:80) was present in 94% at diagnosis. Positive anti–double stranded DNA was present in 82% and low complement levels were present in 84% at diagnosis. This is the first review of childhood onset systemic lupus erythematosus in the Sultanate of Oman.
Factors influencing adherence to medications in a group of patients with systemic lupus erythematosus in Jamaica
Authors: Chambers S , Raine R , Rahman A , Hagley K , De Ceulaer K , Isenberg D 
Published: July 2008

The objective of this study was to examine the factors influencing adherence to medications in a group of patients with systemic lupus erythematosus (SLE) in Jamaica. A qualitative study was designed using a screening questionnaire and semi-structured interviews. The study was conducted in the rheumatology clinic at the University Hospital of the West Indies, Kingston, Jamaica. 75 patients with SLE including 20 interviewees, who had SLE for at least 1 year participated in the study. The main outcome measures were: (i) level of self-reported adherence in a sample of the clinic attendees and (ii) interviewees explanations of the reasons for taking or not taking drugs as prescribed by their physician. 56% of the 75 study participants reported taking their medications more than 85% of the time. High cost and poor availability of medications were the main reasons for poor adherence, but some patients chose not to take their medications because of side effects, perceived mild severity of their disease and/or a preference to take drugs only when symptomatic. Patients used herbal medicines to counteract side effects of Western medicines, to ‘purge the blood’ and to manage lupus symptoms when they had no medications. Religious beliefs were used as a coping strategy. Traditional use of herbal medicines is common particularly in patients from rural Jamaica, and may explain the observed use of herbal medicines in those who have emigrated to developed countries. Socio-economic constraints and poor drug availability are particularly important influences on poor adherence in Jamaican patients with SLE. Religious beliefs and use of herbal remedies do not seem to affect adherence adversely but are used when drugs cannot be obtained.