bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of the CERES Edition 2B Surface-Only Flux Algorithms
Authors: Kratz David P. , Gupta Shashi K. , Wilber Anne C. , Sothcott Victor E. 
Published: July 2009

Abstract
The Clouds and the Earth’s Radiant Energy System (CERES) project uses two shortwave (SW) and two longwave (LW) algorithms to derive surface radiative fluxes on an instantaneous footprint basis from a combination of top-of-atmosphere fluxes, ancillary meteorological data, and retrieved cloud properties. Since the CERES project examines the radiative forcings and feedbacks for Earth’s entire climate system, validation of these models for a wide variety of surface conditions is paramount. The present validation effort focuses upon the ability of these surface-only flux algorithms to produce accurate CERES Edition 2B single scanner footprint data from the Terra and Aqua spacecraft measurements. To facilitate the validation process, high-quality radiometric surface observations have been acquired that were coincident with the CERES-derived surface fluxes. For both SW models, systematic errors range from −20 to −12 W m−2 (from −2.8% to −1.6%) for global clear-sky cases, while for the all-sky SW model, the systematic errors range from 14 to 21 W m−2 (3.2%–4.8%) for global cloudy-sky cases. Larger systematic errors were seen for the individual surface types, and significant random errors where observed, especially for cloudy-sky cases. While the SW models nearly achieved the 20 W m−2 accuracy requirements established for climate research, further improvements are warranted. For the clear-sky LW model, systematic errors were observed to fall within ±5.4 W m−2 (±1.9%) except for the polar case in which systematic errors on the order from −15 to −11 W m−2 (from −13% to −7.2%) occurred. For the all-sky LW model, systematic errors were less than ±9.2 W m−2 (±7.6%) for both the clear-sky and cloudy-sky cases. The random errors were less than 17 W m−2 (6.2%) for clear-sky cases and 28 W m−2 (13%) for cloudy-sky cases, except for the desert cases in which very high surface skin temperatures caused an overestimation in the model-calculated surface fluxes. Overall, however, the LW models met the accuracy requirements for climate research.
Homogeneous and Inhomogeneous Mixing in Cumulus Clouds: Dependence on Local Turbulence Structure
Authors: Lehmann Katrin , Siebert Holger , Shaw Raymond A. 
Published: July 2009

AbstractThe helicopter-borne instrument payload known as the Airborne Cloud Turbulence Observation System (ACTOS) was used to study the entrainment and mixing processes in shallow warm cumulus clouds. The characteristics of the mixing process are determined by the Damköhler number, defined as the ratio of the mixing and a thermodynamic reaction time scale. The definition of the reaction time scale is refined by investigating the relationship between the droplet evaporation time and the phase relaxation time. Following arguments of classical turbulence theory, it is concluded that the description of the mixing process through a single Damköhler number is not sufficient and instead the concept of a transition length scale is introduced. The transition length scale separates the inertial subrange into a range of length scales for which mixing between ambient dry and cloudy air is inhomogeneous, and a range for which the mixing is homogeneous. The new concept is tested on the ACTOS dataset. The effect of entrained subsaturated air on the droplet number size distribution is analyzed using mixing diagrams correlating droplet number concentration and droplet size. The data suggest that homogeneous mixing is more likely to occur in the vicinity of the cloud core, whereas inhomogeneous mixing dominates in more diluted cloud regions. Paluch diagrams are used to support this hypothesis. The observations suggest that homogeneous mixing is favored when the transition length scale exceeds approximately 10 cm. Evidence was found that suggests that under certain conditions mixing can lead to enhanced droplet growth such that the largest droplets are found in the most diluted cloud regions.
Spatial and Temporal Scales of Boundary Layer Wind Predictability in Response to Small-Amplitude Land Surface Uncertainty
Authors: Hacker Joshua P. 
Published: July 2009

AbstractPredictability experiments with the Weather Research and Forecast (WRF) model as a proxy for the atmosphere are analyzed to quantify the spatial and temporal scales of boundary layer wind response to land surface perturbations. Soil moisture is chosen as the land surface variable subject to uncertainty because the atmosphere is known to be sensitive to its state. A range of experiments with spatially correlated, small-amplitude perturbations to soil moisture leads to results that show the dependence of predictability on atmospheric conditions. The primary conclusions are as follows: 1) atmospheric conditions, including static instability and the presence of deep convection, determine whether large errors and local loss of predictability are possible in response to soil moisture errors; 2) the scale of soil moisture uncertainty determines scales of PBL wind predictability when the atmosphere is resistant to upscale error transfer, but when the atmosphere is sensitive the scale and magnitude of soil moisture uncertainty are not important after a few hours; and 3) nonlinear error growth is present whether or not the atmosphere is relatively sensitive to soil moisture uncertainty, leading to doubling times of minutes to hours for finite-sized perturbations. Similar results could be expected from other land surface variables or parameters that exert time-dependent forcing on the atmosphere that is similar in magnitude and scale to that of soil moisture.
Understanding the Characteristics of Daily Precipitation over the United States Using the North American Regional Reanalysis
Authors: Becker Emily J. , Berbery Ernesto Hugo , Higgins R. Wayne 
Published: July 2009

Abstract
This study examines the seasonal characteristics of daily precipitation over the United States using the North American Regional Reanalysis (NARR). To help understand the physical mechanisms that contribute to changes in the characteristics of daily precipitation, vertically integrated moisture flux convergence (MFC) and precipitable water were included in the study. First, an analysis of the NARR precipitation was carried out because while observed precipitation is indirectly assimilated in the system, differences exist. The NARR mean seasonal amount is very close to that of observations throughout the year, although NARR exhibits a slight systematic bias toward more-frequent, lighter precipitation. Particularly during summer, the precipitation intensity and the probability distribution function (PDF) indicate that NARR somewhat underestimates extremes and overestimates lighter events in the eastern half of the United States. The intensity and PDF of moisture flux convergence exhibit a strong similarity to those of precipitation, suggesting a link between strong MFC and precipitation extremes. On the other hand, the relationship between the precipitable water and precipitation PDFs is weaker, based on the lack of agreement of their gamma distribution parameters.
The dependence of the precipitation PDF on the lower-frequency modulation of ENSO was examined. During El Niño winters, the Southwest and central United States, Gulf of Mexico region, and southeastern coast have greater precipitation intensity and extremes than during La Niña, and the Ohio River and Red River basins have lower intensity and fewer extreme events. During summer, the northern Rocky Mountains receive higher intensity precipitation with more extreme events. Most areas where the change in the daily mean precipitation between ENSO phases is large have greater shifts in the extreme tail of the PDF. The ENSO-related response of moisture flux convergence is similar to that of precipitation. ENSO-related shifts in the precipitation PDF do not appear to have a strong relationship to the shifts in precipitable water.
Temperature Trend Patterns in Southern Hemisphere High Latitudes: Novel Indicators of Stratospheric Change
Authors: Lin Pu , Fu Qiang , Solomon Susan , Wallace John M. 
Published: July 2009

Abstract
Robust stratospheric temperature trend patterns are suggested in the winter and spring seasons in the Southern Hemisphere high latitudes from the satellite-borne Microwave Sounding Unit (MSU) measurement for 1979–2007. These patterns serve as indicators of key processes governing temperature and ozone changes in the Antarctic. The observed patterns are characterized by cooling and warming regions of comparable magnitudes, with the strongest local trends occurring in September and October. In September, ozone depletion induces radiative cooling, and strengthening of the Brewer–Dobson circulation (BDC) induces dynamical warming. Because the trends induced by these two processes are centered in different locations in September, they do not cancel each other, but rather produce a wavelike structure. In contrast, during October, the ozone-induced radiative cooling and the BDC-induced warming exhibit a more zonally symmetric structure than in September, and hence largely cancel each other. However, the October quasi-stationary planetary wavenumber 1 has shifted eastward from 1979 to 2007, producing a zonal wavenumber-1 trend structure, which dominates the observed temperature trend pattern.
Simulated temperature changes for 1979–2007 from coupled atmosphere–ocean general circulation model (AOGCM) experiments run for the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) are compared with the observations. In general, the simulated temperature changes are dominated by zonally symmetric ozone-induced radiative cooling. The models fail to simulate the warming in the southern polar stratosphere, implying a lack of the BDC strengthening in these models. They also fail to simulate the quasi-stationary planetary wave changes observed in October and November.
Influence of Lateral Advection on Residual Currents in Microtidal Estuaries
Authors: Cheng Peng , Valle-Levinson Arnoldo 
Published: July 2009

Abstract
The influence of nonlinear lateral advection on estuarine exchange flow is examined with a scaling analysis and eight groups of idealized numerical experiments. Nonlinear lateral advection is related to the linkage between lateral circulation and the lateral shear of the along-estuary flow. The relative contribution of lateral advection to the overall dynamics of a microtidal estuary is found to be a function of width and depth, and of vertical mixing. Lateral advection is dynamically important in narrow and deep estuaries, particularly under relatively weak vertical mixing. The relative importance of lateral advection and the earth’s rotation on estuarine dynamics can be evaluated in terms of the nondimensional Rossby and Ekman numbers (Ro and Ek). Lateral advection is most effective at large Ro and small Ek and is negligible at small Ro and large Ek. As expected, the earth’s rotation is most significant at small Ro and Ek, and is negligible at large Ro and Ek. Under the influence of lateral advection and the earth’s rotation, the lateral structure of estuarine exchange flows is a function of Ro and Ek. In some instances, the exchange flow is vertically sheared and in others it is laterally sheared. Classical estuarine dynamics, which yields vertically sheared exchange flows, occurs at intermediate Ro and large Ek. The main role of lateral advection is to reduce lateral variability of estuarine exchange flow and generate a vertically sheared, two-layer exchange flow structure.
Weather Radar Ground Clutter. Part I: Identification, Modeling, and Simulation
Authors: Hubbert J. C. , Dixon M. , Ellis S. M. , Meymaris G. 
Published: July 2009

Abstract
Real-time ground-clutter identification and subsequent filtering of clutter-contaminated data is addressed in this two-part paper. Part I focuses on the identification, modeling, and simulation of S-band ground-clutter echo. A new clutter identification parameter, clutter phase alignment (CPA), is presented. CPA is a measure primarily of the phase variability of the in-phase and quadrature-phase time series samples for a given radar resolution volume. CPA is also a function of amplitude variability of the time series. It is shown that CPA is an excellent discriminator of ground clutter versus precipitation echoes. A typically used weather model, time series simulator is shown to inadequately describe experimentally observed CPA. Thus, a new technique for the simulation of ground-clutter echo is developed that better predicts the experimentally observed CPA. Experimental data from the Denver Next Generation Weather Radar (NEXRAD) at the Denver, Colorado, Front Range Airport (KFTG), and NCAR’s S-band dual-polarization Doppler radar (S-Pol) are used to illustrate CPA. In Part II, CPA is used in a fuzzy logic algorithm for improved clutter identification.
Weather Radar Ground Clutter. Part II: Real-Time Identification and Filtering
Authors: Hubbert J. C. , Dixon M. , Ellis S. M. 
Published: July 2009

Abstract
The identification and mitigation of anomalous propagation (AP) and normal propagation (NP) ground clutter is an ongoing problem in radar meteorology. Scatter from ground-clutter targets routinely contaminates radar data and masks weather returns causing poor data quality. The problem is typically mitigated by applying a clutter filter to all radar data, but this also biases weather data at near-zero velocity. Modern radar processors make possible the real-time identification and filtering of AP clutter. A fuzzy logic algorithm is used to distinguish between clutter echoes and precipitation echoes and, subsequently, a clutter filter is applied to those radar resolution volumes where clutter is present. In this way, zero-velocity weather echoes are preserved while clutter echoes are mitigated. Since the radar moments are recalculated from clutter-filtered echoes, the underlying weather echo signatures are revealed, thereby significantly increasing the visibility of weather echo. This paper describes the fuzzy logic algorithm, clutter mitigation decision (CMD), for clutter echo identification. A new feature field, clutter phase alignment (CPA), is introduced and described. A detailed discussion of CPA is given in Part I of this paper. The CMD algorithm is illustrated with experimental data from the Denver Next Generation Weather Radar (NEXRAD) at the Denver, Colorado, Front Range Airport (KFTG); and NCAR’s S-band dual-polarization Doppler radar (S-Pol).
Measurements of Sea Surface Height Variability in the Eastern South Atlantic from Pressure Sensor–Equipped Inverted Echo Sounders: Baroclinic and Barotropic Components
Authors: Baker-Yeboah Sheekela , Watts D. Randolph , Byrne Deirdre A. 
Published: July 2009

Abstract
Variability in sea surface height (SSH) can be decomposed into two contributions: one from changes in mass in the water column (barotropic) and the other from purely steric changes (baroclinic). Both contributions can be determined from data recorded by a pressure sensor–equipped inverted echo sounder (PIES). PIES data from the Agulhas South Atlantic Thermohaline Experiment (ASTTEX) were used, collected in the Cape Basin off South Africa, along 1000 km of an eddy corridor where Agulhas eddies carry cores of warm, salty Indian Ocean waters into the South Atlantic. The paper presents in detail the method used to convert PIES measurements into barotropic, baroclinic, and total SSH, and discusses the error budget. The baroclinic contribution is geopotential height (reference 4500 dbar), which can be determined from the measured vertical acoustic travel time together with a lookup curve based on the regional hydrography. The main error source is scatter about this curve that depends on the extent to which water masses advecting along each geopotential streamline may derive from different ocean regions. The barotropic contribution can be determined from the bottom pressure measurements of the mass variation in the water column and has an uncertainty due to sensor calibration drift in two years corresponding to 1-cm water column height. The barotropic component accounts for 20% of the overall SSH variance and 47% during large signal intervals exceeding 15 cm. PIES data demonstrate via the two measurements that barotropic and baroclinic contributions may work independently or in concert in different mesoscale eddies. The combined structure need not be equivalent barotropic. In particular, deep barotropic eddies exhibit mesoscale spatiotemporal scales and may or may not be systematically tilted or aligned in space or time relative to baroclinic eddies.
Remote Real-Time Video-Enabled Docking for Underwater Autonomous Platforms
Authors: Moline Mark A. , Schofield Oscar 
Published: July 2009

Abstract
One of the key challenges in the development and implementation of ocean observatories is sustained observations over relevant temporal and spatial scales. Autonomous underwater vehicles (AUVs) have demonstrated their potential for synoptic spatial coverage of regions of scientific and strategic interest. The range and duration of these systems are limited, however, to the capabilities of a single charge. A few efforts have been made to develop docking systems for propeller-driven vehicles; however, these systems are not applicable for buoyancy-driven gliders and cannot be universally applied to AUVs. Here the authors introduce an alternative strategy for AUV docking, demonstrate feasibility with a series of field tests using a remotely operated vehicle (ROV) to remotely recover an AUV, and comment on the scalability within the framework of the evolving global ocean observatory initiatives. Implementation of simple strategies such as this has the potential to reduce the chronic problem of undersampling in the ocean and may facilitate addressing some outstanding scientific questions related to the ocean.
Aberrant overexpression of microRNAs activate AKT signaling via down-regulation of tumor suppressors in natural killer–cell lymphoma/leukemia
Authors: Yamanaka Yasuo , Tagawa Hiroyuki , Takahashi Naoto , Watanabe Atsushi , Guo Yong-Mei , Iwamoto Keiko , Yamashita Junsuke , Saitoh Hirobumi , Kameoka Yoshihiro , Shimizu Norio , Ichinohasama Ryo , Sawada Ken-ichi 
Published: July 2009

AbstractThe gene(s) responsible for natural killer (NK)–cell lymphoma/leukemia have not been identified. In the present study, we found that in NK-cell lymphoma lines (n = 10) and specimens of primary lymphoma (n = 10), levels of miR-21 and miR-155 expression were inversely related and were significantly greater than those found in normal natural killer (CD3−CD56+) cells (n = 8). To determine the functions of these microRNAs in lymphomagenesis, we examined the effects of antisense oligonucleotides (ASOs) targeting miR-21 (ASO-21) and/or miR-155 (ASO-155) in NK-cell lymphoma lines overexpressing one or both of these miRNAs. Conversely, cells showing little endogenous expression of miR-21 or miR-155 were transduced by the use of lentiviral vectors, leading to their overexpression. Reducing expression of miR-21 or miR-155 led to up-regulation of phosphatase and tensin homologue (PTEN), programmed cell death 4 (PDCD4), or Src homology-2 domain-containing inositol 5-phosphatase 1 (SHIP1). ASO-21– and ASO-155–treated cell lines all showed down-regulation of phosphorylated AKTser473. Moreover, transduction with either miR-21 or miR-155 led to down-regulation of PTEN and PDCD4 or SHIP1 with up-regulation of phosphorylated AKTser473. Collectively, these results provide important new insight into the pathogenesis of NK-cell lymphoma/leukemia and suggest targeting miR-21 and/or miR-155 may represent a useful approach to treating NK-cell lymphoma/leukemia.
Endobronchial ultrasound-guided transbronchial needle aspiration for identifying EGFR mutations
Authors: Garcia-Olivé I. , Monsó E. , Andreo F. , Sanz-Santos J. , Taron M. , Molina-Vila M. A. , Llatjós M. , Castellà E. , Moran T. , Bertran-Alamillo J. , Mayo-de-las-Casas C. , Queralt C. , Rosell R. 
Published: July 2009

The presence of somatic mutations of the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene in patients with advanced nonsmall cell lung cancer (NSCLC) correlates with a good response to tyrosine kinase inhibitors. The usefulness of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for the detection of EGFR mutations in cells recovered from malignant mediastinal nodes in patients with NSCLC was assessed.All patients with lung adenocarcinoma or unspecified NSCLC referred for staging with EBUS-TBNA were included. Nodes with a short-axis diameter of >5 mm were sampled, and genomic DNA from metastatic tumour cells was obtained for analysis of exons 19 and 21. The impact of sampling on management was assessed.EGFR gene analysis of the EBUS-TBNA sample was feasible in 26 (72.2%) out of the 36 patients with lymph node metastasis. Somatic mutations of the EGFR gene were detected in tissue obtained through EBUS-TBNA in two (10%) out of 20 patients with metastasic lung adenocarcinoma.Malignant tissue samples obtained by EBUS-TBNA from patients with nodal metastasis of NSCLC are suitable for the detection of EGFR mutations in most cases, and this technique demonstrates mutated neoplastic cells in a tenth of patients with adenocarcinoma.
Long-term effects of a partially supervised conditioning programme in cystic fibrosis
Authors: Hebestreit H. , Kieser S. , Junge S. , Ballmann M. , Hebestreit A. , Schindler C. , Schenk T. , Posselt H-G. , Kriemler S. 
Published: July 2009

Little is known about the long-term persistence of positive effects induced by a physical conditioning programme in cystic fibrosis. Therefore, this study determined the effects of a 6-month conditioning programme on peak oxygen uptake (primary outcome) and other markers of fitness, physical activity, anthropometry, lung function and quality of life (secondary outcomes), 18 and 24 months after the programme was initiated.Patients with cystic fibrosis aged 12–40 yrs were randomly assigned to an intervention (n = 23) and a control (n = 15) group. The intervention group consented to add 3 h of sports per week for ≥6 months to their previous activities. Controls were asked to maintain their level of activity for 12 months. Patients were seen at baseline and after 3, 6, 12, 18 and 24 months.There was no significant difference between groups at baseline. The intervention induced positive effects on peak oxygen uptake (difference in changes from baseline to the 18- and 24-month assessments between groups: 3.72±1.23 mL·min−1·kg−1; p<0.01), maximal workload (0.37±0.11 W·kg−1; p<0.01), vigorous physical activity (1.63±0.82 h·week−1; p<0.05), forced vital capacity (6.06±2.87% predicted; p<0.05) and perceived health (9.89±4.72; p<0.05).A home-based partially supervised physical conditioning programme can improve physical fitness, lung function and perceived health long after the intervention has ended.