bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leading Tropical Modes Associated with Interannual and Multidecadal Fluctuations in North Atlantic Hurricane Activity
Authors: Bell Gerald D. , Chelliah Muthuvel 
Published: March 2006

Abstract
Interannual and multidecadal extremes in Atlantic hurricane activity are shown to result from a coherent and interrelated set of atmospheric and oceanic conditions associated with three leading modes of climate variability in the Tropics. All three modes are related to fluctuations in tropical convection, with two representing the leading multidecadal modes of convective rainfall variability, and one representing the leading interannual mode (ENSO).
The tropical multidecadal modes are shown to link known fluctuations in Atlantic hurricane activity, West African monsoon rainfall, and Atlantic sea surface temperatures, to the Tropics-wide climate variability. These modes also capture an east–west seesaw in anomalous convection between the West African monsoon region and the Amazon basin, which helps to account for the interhemispheric symmetry of the 200-hPa streamfunction anomalies across the Atlantic Ocean and Africa, the 200-hPa divergent wind anomalies, and both the structure and spatial scale of the low-level tropical wind anomalies, associated with multidecadal extremes in Atlantic hurricane activity.
While there are many similarities between the 1950–69 and 1995–2004 periods of above-normal Atlantic hurricane activity, important differences in the tropical climate are also identified, which indicates that the above-normal activity since 1995 does not reflect an exact return to conditions seen during the 1950s–60s. In particular, the period 1950–69 shows a strong link to the leading tropical multidecadal mode (TMM), whereas the 1995–2002 period is associated with a sharp increase in amplitude of the second leading tropical multidecadal mode (TMM2). These differences include a very strong West African monsoon circulation and near-average sea surface temperatures across the central tropical Atlantic during 1950–69, compared with a modestly enhanced West African monsoon and exceptionally warm Atlantic sea surface temperatures during 1995–2004.
It is shown that the ENSO teleconnections and impacts on Atlantic hurricane activity can be substantially masked or accentuated by the leading multidecadal modes. This leads to the important result that these modes provide a substantially more complete view of the climate control over Atlantic hurricane activity during individual seasons than is afforded by ENSO alone. This result applies to understanding differences in the “apparent” ENSO teleconnections not only between the above- and below-normal hurricane decades, but also between the two sets of above-normal hurricane decades.
Independent Evaluation of the Ability of Spaceborne Radar and Lidar to Retrieve the Microphysical and Radiative Properties of Ice Clouds
Authors: Hogan Robin J. , Brooks Malcolm E. , Illingworth Anthony J. , Donovan David P. , Tinel Claire , Bouniol Dominique , Baptista J. Pedro V. Poiares 
Published: March 2006

Abstract
The combination of radar and lidar in space offers the unique potential to retrieve vertical profiles of ice water content and particle size globally, and two algorithms developed recently claim to have overcome the principal difficulty with this approach—that of correcting the lidar signal for extinction. In this paper “blind tests” of these algorithms are carried out, using realistic 94-GHz radar and 355-nm lidar backscatter profiles simulated from aircraft-measured size spectra, and including the effects of molecular scattering, multiple scattering, and instrument noise. Radiation calculations are performed on the true and retrieved microphysical profiles to estimate the accuracy with which radiative flux profiles could be inferred remotely. It is found that the visible extinction profile can be retrieved independent of assumptions on the nature of the size distribution, the habit of the particles, the mean extinction-to-backscatter ratio, or errors in instrument calibration. Local errors in retrieved extinction can occur in proportion to local fluctuations in the extinction-to-backscatter ratio, but down to 400 m above the height of the lowest lidar return, optical depth is typically retrieved to better than 0.2. Retrieval uncertainties are greater at the far end of the profile, and errors in total optical depth can exceed 1, which changes the shortwave radiative effect of the cloud by around 20%. Longwave fluxes are much less sensitive to errors in total optical depth, and may generally be calculated to better than 2 W m−2 throughout the profile. It is important for retrieval algorithms to account for the effects of lidar multiple scattering, because if this is neglected, then optical depth is underestimated by approximately 35%, resulting in cloud radiative effects being underestimated by around 30% in the shortwave and 15% in the longwave. Unlike the extinction coefficient, the inferred ice water content and particle size can vary by 30%, depending on the assumed mass–size relationship (a problem common to all remote retrieval algorithms). However, radiative fluxes are almost completely determined by the extinction profile, and if this is correct, then errors in these other parameters have only a small effect in the shortwave (around 6%, compared to that of clear sky) and a negligible effect in the longwave.
Raman Lidar Measurements during the International H2O Project. Part II: Case Studies
Authors: Whiteman D. N. , Demoz B. , Schwemmer G. , Gentry B. , Di Girolamo P. , Sabatino D. , Comer J. , Veselovskii I. , Evans K. , Lin R-F. , Wang Z. , Behrendt A. , Wulfmeyer V. , Browell E. , Ferrare R. , Ismail S. , Wang J. 
Published: March 2006

Abstract
The NASA GSFC Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP) that occurred in May and June 2002 in the midwestern part of the United States. The SRL system configuration and methods of data analysis were described in Part I of this paper. In this second part, comparisons of SRL water vapor measurements and those of Lidar Atmospheric Sensing Experiment (LASE) airborne water vapor lidar and chilled-mirror radiosonde are performed. Two case studies are then presented: one for daytime and one for nighttime. The daytime case study is of a convectively driven boundary layer event and is used to characterize the daytime SRL water vapor random error characteristics. The nighttime case study is of a thunderstorm-generated cirrus cloud case that is studied in its meteorological context. Upper-tropospheric humidification due to precipitation from the cirrus cloud is quantified as is the cirrus cloud optical depth, extinction-to-backscatter ratio, ice water content, cirrus particle size, and both particle and volume depolarization ratios. A stability and back-trajectory analysis is performed to study the origin of wave activity in one of the cloud layers. These unprecedented cirrus cloud measurements are being used in a cirrus cloud modeling study.
A New Approach to Estimate Directional Spreading Parameters of a Cosine-2s Model
Authors: Zhang Shaosong , Zhang Jun 
Published: March 2006

Abstract
For accurate and consistent estimates of the directional spreading parameter and mean wave direction of directional seas based on a cosine-2s directional spreading model, a new approach is proposed, employing a maximum likelihood method (MLM) to estimate the directional spreading function and then the angular Fourier coefficients. Because an MLM is more tolerant of errors in the estimated cross-spectrum than a directional Fourier transfer used in the conventional approach, the proposed approach is able to estimate the directional spreading parameter more accurately and consistently, which is examined and confirmed by applying the proposed approach and conventional approach, respectively, to the time series generated by numerical simulation and recorded in field measurements.
Immersion Factor of In-Water Radiance Sensors: Assessment for a Class of Radiometers
Authors: Zibordi Giuseppe 
Published: March 2006

AbstractThe spectral immersion factor of in-water radiance sensors If quantifies the effects of changes in the sensor's response when operated in water versus in air. The values of If are currently computed with a relationship derived from a basic sensor model, which only requires knowledge of the refractive indices of the water and the material constituting the sensor's optical window in contact herewith. Uncertainties in the computation of If are investigated in the 400–700-nm spectral range for a specific class of widely used multispectral radiometers. The analysis is made by comparing If values from the theoretical relationship currently in use with (i) If from a new relationship based on an extended sensor model accounting for the actual solid-angle field of view and the reflectance and transmittance of the external and internal optical components, and (ii) experimental If determined with sample radiometers having diverse optical windows made of materials with different refractive indices. Results highlight that the relationship derived from the basic sensor model introduces a 0.4% negative bias when applied to the considered class of radiometers having a fused silica optical window, a 13° in-air half-angle field of view, and an estimated detector reflectance of 0.15. Reference values of If for the specific class of radiometers, determined with the newly proposed relationship, are presented, and their dependence on seawater temperature and salinity is discussed.
Aliasing of Sea Level Sampled by a Single Exact-Repeat Altimetric Satellite or a Coordinated Constellation of Satellites: Analytic Aliasing Formulas
Authors: Tai Chang-Kou 
Published: March 2006

Abstract
The aliasing problem for exact-repeat altimetric satellite sampling is solved analytically by the least squares method. To make the problem tractable, the latitudinal extent of the problem needs to be moderate for the satellite ground tracks to appear as two sets of parallel straight lines, and the along-track sampling is assumed to be dense enough to resolve any along-track features of interest. The aliasing formulas thus derived confirm the previously discovered resolving power, which is characterized by the Nyquist frequency ωc = π/T (where T is the repeat period of the satellite) and by (in local Cartesian coordinates) the zonal and meridional Nyquist wavenumbers kc = 2π/X and lc = 2π/Y, respectively (where X and Y are the east–west and north–south separations between adjacent parallel ground tracks). There are three major differences with the textbook aliasing. First, instead of the one-to-one correspondence, an outside spectral component is usually aliased into more than one inside spectral components (i.e., those inside the resolved spectral range with |ω| &lt; ωc, |k| &lt; kc, and |l| &lt; lc). Second, instead of power conservation, the aliased components have less power than their corresponding outside spectral components. Third, not all outside components are aliased into the resolved range. Rather, only outside components inside certain well-defined regions in the spectral space are aliased inside. Numerical confirmation of these formulas has been achieved. Moreover, the soundness of these formulas is demonstrated through real examples of tidal aliasing. Furthermore, it is shown that these results can be generalized easily to the case with a coordinated constellation of satellites. The least squares methodology yields the optimal solution, that is, the best fitting, as well as yielding the least aliasing. However, the usual practice is to smooth (i.e., low-pass filter) the altimeter data onto a regular space–time grid. The framework for computing the aliasing of smoothed altimeter data is provided. The smoothing approach produces two major differences with the least squares results. First, the one-to-one correspondence of aliasing is mostly restored. Second, and more important, smoothing reduces the effective Nyquist wavenumbers to π/X = kc/2 and π/Y = lc/2, respectively (i.e., the resolved spectral space is reduced to a quarter of the size that is obtained by the least squares methodology). Ironically, the more one tries to filter out the small-scale features, the more precise the above statement becomes. However, like the least squares results, only outside components inside certain well-defined regions in the spectral space are aliased inside, and this occurs with less power. How much less depends on the characteristics of the smoother.
Solar Irradiance and Effective Brightness Temperature for SWIR Channels of AVHRR/NOAA and GOES Imagers
Authors: Trishchenko Alexander P. 
Published: March 2006

Abstract
Satellite observations in the shortwave infrared (SWIR) part of spectrum between 3.5 and 4.0 μm deliver critically important information for many applications. The satellite signal in this spectral band consists of solar-reflected radiation and thermal radiation emitted by surface, clouds, and atmosphere. Accurate retrievals require precise knowledge of solar irradiance values within a channel's bandwidth. The magnitudes of solar irradiance for shortwave infrared channels (3.7–3.9 μm) for the Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration-7 (NOAA-7) to NOAA-18 satellites and the Geostationary Operational Environmental Satellite-8 (GOES-8) to GOES-12 are considered in this paper. Four recent solar reference spectra [those of Kurucz, Gueymard, the American Society for Testing and Materials (ASTM), and Wehrli] are analyzed to determine uncertainties in the knowledge of solar irradiance values for SWIR channels of the listed sensors. Because thermal radiation is frequently converted to effective blackbody temperature for analysis, computations, and calibration purposes, it is proposed here to express band-limited solar irradiance values in terms of brightness temperature as well. It is shown that band-limited solar irradiance for AVHRR radiometers expressed in terms of blackbody equivalent brightness temperature correspond to the range 355–360 K, and vary around 345 K for the SWIR channels of the GOES imagers. The values of band-limited solar irradiance and brightness temperatures are provided for various reference solar spectra. The relative differences in band-limited solar irradiance computed for the considered reference solar spectra are between 0% and 2.5%. Differences expressed in terms of brightness temperatures may reach 0.8 K. The results for the ASTM and the Kurucz reference spectra agree within 0.1% relative difference. Parameters of linear fits relating effective brightness temperatures and spectral radiance equivalent temperatures are also determined for all sensors. They are required for precise radiance–temperature and temperature–radiance conversion through Planck's functions in the case of the finite spectral response of real sensors.
Quality Control of Weather Data during Extreme Events
Authors: You Jinsheng , Hubbard Kenneth G. 
Published: March 2006

Abstract
Quality assurance (QA) procedures have been automated to reduce the time and labor necessary to discover outliers in weather data. Measurements from neighboring stations are used in this study in a spatial regression test to provide preliminary estimates of the measured data points. The new method does not assign the largest weight to the nearest estimate but, instead, assigns the weights according to the standard error of estimate. In this paper, the spatial test was employed to study patterns in flagged data in the following extreme events: the 1993 Midwest floods, the 2002 drought, Hurricane Andrew (1992), and a series of cold fronts during October 1990. The location of flagged records and the influence zones for such events relative to QA were compared. The behavior of the spatial test in these events provides important information on the probability of making a type I error in the assignment of the quality control flag. Simple pattern recognition tools that identify zones wherein frequent flagging occurs are illustrated. These tools serve as a means of resetting QA flags to minimize the number of type I errors as demonstrated for the extreme events included here.
Maintained inspiratory activity during proportional assist ventilation in surfactant-depleted cats early after surfactant instillation: phrenic nerve and pulmonary stretch receptor activity
Authors: Sindelar Richard , Rieger-Fackeldey Esther , Jonzon Anders , Schaller Peter , Schulze Andreas , Sedin Gunnar 
Published: March 2006

Abstract

Background
Inspiratory activity is a prerequisite for successful application of patient triggered ventilation such as proportional assist ventilation (PAV). It has recently been reported that surfactant instillation increases the activity of slowly adapting pulmonary stretch receptors (PSRs) followed by a shorter inspiratory time (Sindelar et al, J Appl Physiol, 2005 [Epub ahead of print]). Changes in lung mechanics, as observed in preterm infants with respiratory distress syndrome and after surfactant treatment, might therefore influence the inspiratory activity when applying PAV early after surfactant treatment.

Objective
To investigate the regulation of breathing and ventilatory response in surfactant-depleted young cats during PAV and during continuous positive airway pressure (CPAP) early after surfactant instillation in relation to phrenic nerve activity (PNA) and the activity of PSRs.

Methods
Seven anesthetized, endotracheally intubated young cats were exposed to periods of CPAP and PAV with the same end-expiratory pressure (0.2–0.5 kPa) before and after lung lavage and after surfactant instillation. PAV was set to compensate for 75% of the lung elastic recoil.

Results
Tidal volume and respiratory rate were higher with lower PaCO2 and higher PaO2 during PAV than during CPAP both before and after surfactant instillation (p < 0.05; both conditions). As an indicator of breathing effort, esophageal deflection pressure and PNA were lower during PAV than during CPAP in both conditions (p < 0.02). Peak PSR activity was higher and occurred earlier during PAV than during CPAP (p < 0.01), and correlated linearly with PNA duration in all conditions studied (p < 0.001). The inspiratory time decreased as tidal volume increased when CPAP was changed to PAV, with the highest correlation observed after surfactant instillation (r = -0.769). No apneic periods could be observed.

Conclusion
PSR activity and the control of breathing are maintained during PAV in surfactant-depleted cats early after surfactant instillation, with a higher ventilatory response and a lower breathing effort than during CPAP.
SimArray: a user-friendly and user-configurable microarray design tool
Authors: Auburn Richard P , Russell Roslin R , Fischer Bettina , Meadows Lisa A , Sevillano Matilla Santiago , Russell Steven 
Published: March 2006

Abstract

Background
Microarrays were first developed to assess gene expression but are now also used to map protein-binding sites and to assess allelic variation between individuals. Regardless of the intended application, efficient production and appropriate array design are key determinants of experimental success. Inefficient production can make larger-scale studies prohibitively expensive, whereas poor array design makes normalisation and data analysis problematic.

Results
We have developed a user-friendly tool, SimArray, which generates a randomised spot layout, computes a maximum meta-grid area, and estimates the print time, in response to user-specified design decisions. Selected parameters include: the number of probes to be printed; the microtitre plate format; the printing pin configuration, and the achievable spot density. SimArray is compatible with all current robotic spotters that employ 96-, 384- or 1536-well microtitre plates, and can be configured to reflect most production environments. Print time and maximum meta-grid area estimates facilitate evaluation of each array design for its suitability. Randomisation of the spot layout facilitates correction of systematic biases by normalisation.

Conclusion
SimArray is intended to help both established researchers and those new to the microarray field to develop microarray designs with randomised spot layouts that are compatible with their specific production environment. SimArray is an open-source program and is available from http://www.flychip.org.uk/SimArray/.
The effect of oligonucleotide microarray data pre-processing on the analysis of patient-cohort studies
Authors: Verhaak Roel GW , Staal Frank JT , Valk Peter JM , Lowenberg Bob , Reinders Marcel JT , de Ridder Dick 
Published: March 2006

Abstract

Background
Intensity values measured by Affymetrix microarrays have to be both normalized, to be able to compare different microarrays by removing non-biological variation, and summarized, generating the final probe set expression values. Various pre-processing techniques, such as dChip, GCRMA, RMA and MAS have been developed for this purpose. This study assesses the effect of applying different pre-processing methods on the results of analyses of large Affymetrix datasets. By focusing on practical applications of microarray-based research, this study provides insight into the relevance of pre-processing procedures to biology-oriented researchers.

Results
Using two publicly available datasets, i.e., gene-expression data of 285 patients with Acute Myeloid Leukemia (AML, Affymetrix HG-U133A GeneChip) and 42 samples of tumor tissue of the embryonal central nervous system (CNS, Affymetrix HuGeneFL GeneChip), we tested the effect of the four pre-processing strategies mentioned above, on (1) expression level measurements, (2) detection of differential expression, (3) cluster analysis and (4) classification of samples. In most cases, the effect of pre-processing is relatively small compared to other choices made in an analysis for the AML dataset, but has a more profound effect on the outcome of the CNS dataset. Analyses on individual probe sets, such as testing for differential expression, are affected most; supervised, multivariate analyses such as classification are far less sensitive to pre-processing.

Conclusion
Using two experimental datasets, we show that the choice of pre-processing method is of relatively minor influence on the final analysis outcome of large microarray studies whereas it can have important effects on the results of a smaller study. The data source (platform, tissue homogeneity, RNA quality) is potentially of bigger importance than the choice of pre-processing method.