bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics of Low-Level Jets over Northern Taiwan in Mei-Yu Season and Their Relationship to Heavy Rain Events
Authors: Chen George Tai-Jen , Wang Chung-Chieh , Lin David Ta-Wei 
Published: March 2005

Abstract
The present study investigates the characteristics of low-level jets (LLJs) (≥12.5 m s−1) below 600 hPa over northern Taiwan in the mei-yu season and their relationship to heavy rainfall events (≥50 mm in 24 h) through the use of 12-h sounding data, weather maps at 850 and 700 hPa, and hourly rainfall data at six surface stations during the period of May–June 1985–94. All LLJs are classified based on their height, appearance (single jet or double jet), and movement (migratory and nonmigratory). The frequency, vertical structure, and spatial and temporal distribution of LLJs relative to the onset of heavy precipitation are discussed.
Results on the general characteristics of LLJs suggest that they occurred about 15% of the time in northern Taiwan, with a top speed below 40 m s−1. The level of maximum wind appeared mostly between 850 and 700 hPa, with highest frequency at 825–850 hPa. A single jet was observed more often (76%) than a double jet (24%), while in the latter case a barrier jet usually existed at 900–925 hPa as the lower branch.
Migratory and nonmigratory LLJs each constituted about half of all cases, and there existed no apparent relationship between their appearance and movement. Migratory LLJs tended to be larger in size, stronger over a thicker layer, more persistent, and were much more closely linked to heavy rainfall than nonmigratory jets. They often formed over southern China between 20° and 30°N and moved toward Taiwan presumably along with the mei-yu frontal system.
Before and near the onset of the more severe heavy rain events (≥100 mm in 24 h) in northern Taiwan, there was a 94% chance that an LLJ would be present over an adjacent region at 850 hPa, and 88% at 700 hPa, in agreement with earlier studies. Occurrence frequencies of LLJs for less severe events (50–100 mm in 24 h) were considerably lower, and the difference in accumulative rainfall amount was seemingly also affected by the morphology of the LLJs, including their strength, depth, elevation of maximum wind, persistence, proximity to northern Taiwan, source region of moisture, and their relative timing of arrival before rainfall. During the data period, about 40% of all migratory LLJs at 850 or 700 hPa passing over northern Taiwan were associated with heavy rainfall within the next 24 h. The figure, however, was much lower compared to earlier studies, and some possible reasons are offered to account for this deficit.
Spectral (Bin) Microphysics Coupled with a Mesoscale Model (MM5). Part II: Simulation of a CaPE Rain Event with a Squall Line
Authors: Lynn Barry H. , Khain Alexander P. , Dudhia Jimy , Rosenfeld Daniel , Pokrovsky Andrei , Seifert Axel 
Published: March 2005

Abstract
Spectral (bin) microphysics (SBM) has been implemented into the three-dimensional fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). The new model was used to simulate a squall line that developed over Florida on 27 July 1991. It is shown that SBM reproduces precipitation rate, rain amounts, and location, radar reflectivity, and cloud structure much better than bulk parameterizations currently implemented in MM5.
Sensitivity tests show the importance of (i) raindrop breakup, (ii) in-cloud turbulence, (iii) different aerosol concentrations, and (iv) inclusion of scavenging of aerosols. Breakup decreases average and maximum rainfall. In-cloud turbulence enhances particle drop collision rates and increases rain rates. A “continental” aerosol concentration produces a much larger maximum rainfall rate versus that obtained with “maritime” aerosol concentration. At the same time accumulated rain is larger with maritime aerosol concentration. The scavenging of aerosols by nucleating water droplets strongly affected the concentration of aerosols in the atmosphere.
The spectral (bin) microphysics mesoscale model can potentially be used for studies of specific phenomena such as severe storms, winter storms, tropical cyclones, etc. The more realistic reproduction of cloud structure than that obtained with bulk parameterization implies that the model will be more useful for remote sensing applications and in the development of advanced rain retrieval algorithms. The model can also simulate the effect of cloud seeding on rain production.
The Diurnal Cycle of Land–Atmosphere Interactions across Oklahoma’s Winter Wheat Belt
Authors: Haugland Matthew J. , Crawford Kenneth C. 
Published: March 2005

Abstract
This manuscript documents the impact of Oklahoma’s winter wheat belt (WWB) on the near-surface atmosphere by comparing the diurnal cycle of meteorological conditions within the WWB relative to conditions in adjacent counties before and after the wheat harvest.
To isolate the impact of the winter wheat belt on the atmosphere, data from several meteorological parameters were averaged to create a diurnal cycle before and after the wheat harvest. Observations from 17 Oklahoma Mesonet sites within the WWB (during a period of 9 yr) were compared with observations from 22 Mesonet sites in adjacent counties outside the winter wheat belt.
The average diurnal cycles of dewpoint, temperature, and surface pressure exhibited patterns that revealed a distinct mesoscale impact of the wheat fields. The diurnal patterns were consistent with the status of the wheat crop and the grassland in adjacent counties. The impact of the WWB was shown to be more significant during a month when soil moisture was abundant, and minimal during a month when soil moisture was limited. Statistically significant, hydrostatically consistent afternoon surface pressure anomalies suggest that there is a strong possibility of weak mesoscale circulations induced by the WWB.
Characteristics of Monsoon Rainfall around the Himalayas Revealed by TRMM Precipitation Radar
Authors: Bhatt B. C. , Nakamura K. 
Published: March 2005

Abstract
The climatological features of the diurnal cycle and its spatial and temporal variability are investigated around the Himalayas using hourly, 0.05° × 0.05° grid, near-surface rainfall data from the Precipitation Radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) satellite during June–July–August (JJA) of 1998–2002. Though sampling errors inherent to TRMM PR measurements around the Himalayas could influence results, PR-observed precipitation features show agreement with previous studies in this region.
The analysis of precipitation characteristics presented here is based on two rain-rate thresholds: (a) light rain rate (≤5 mm h−1), and (b) moderate to heavy rain rate (&gt;5 mm h−1). The results suggest that afternoon to evening precipitation is noticed as embedded convection within a large region of light rain over the south-facing slopes of the Himalayas. The moderate to heavy conditional rain rate exhibits a relatively stronger diurnal cycle of precipitation in this region. However, this may be biased because of sampling. Almost all the Tibetan Plateau shows light rain activity.
The Tibetan Plateau and northern Indian subcontinent regions are characterized by daytime maximum precipitation. From the analysis of near-surface rainfall over the finescale topography, it is observed that daytime (1200–1800 LT) precipitation is concentrated over the ridges and strong ridge–valley gradients with rain appearing over the south-facing slopes of the Himalayas. During midnight–early morning, intense rainfall concentrates over the ridges as well as in river valleys. Precipitation broadening and movement are noticed during this time period.
Tracer Advection Using Dynamic Grid Adaptation and MM5
Authors: Iselin John P. , Gutowski William J. , Prusa Joseph M. 
Published: March 2005

Abstract
A dynamic grid adaptation (DGA) technique is used to numerically simulate tracer transport at meso- and regional scales. A gridpoint redistribution scheme is designed to maximize heuristic characteristics of a “good” grid. The advective solver used in conjunction with the DGA is the multidimensional positive definite advection transport algorithm (MPDATA). The DGA results for regional tracer transport are compared against results generated using the leapfrog as well as MPDATA advection schemes with uniformly spaced, static grids. Wind fields for all tracer transport algorithms are provided by the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). A mesoscale-sized test case with idealized initial condition and wind field clearly shows qualitatively and quantitatively the advantage of using the dynamic adaptive grid, which is a marked reduction in numerical error. These results are further corroborated by more realistic test cases that used NCEP–NCAR reanalysis data from 6–11 March 1992 to set initial and boundary conditions for (i) a mesoscale-sized, 24-h simulation with an idealized initial tracer field, and (ii) a regional, 5-day simulation with water vapor field initialized from the reanalysis data but then treated as a passive tracer. A result of interest is that MPDATA substantially outperforms the leapfrog method with fourth-order artificial dissipation (central to MM5) in all of our test cases. We conclude that with dynamic grid adaptation, results with approximately the same accuracy as a uniform grid may be obtained using only a quarter of the grid points of the uniform grid MPDATA simulations. Compared to results generated using the leapfrog method on a uniform grid, the DGA does even better.
Convective Initiation ahead of the Sea-Breeze Front
Authors: Fovell Robert G. 
Published: March 2005

Abstract
In earlier work, a three-dimensional cloud model was used to simulate the interaction between the sea-breeze front (SBF) and front-parallel horizontal convective rolls (HCRs), resulting in the SBF systematically encountering roll updrafts and downdrafts as it progressed inland. Interestingly, deep convection was spawned above an HCR updraft ahead of the SBF as the front approached, well before the inevitable front–roll merger. Ostensibly, both the sea-breeze and roll circulations were required for deep convection to be present in this case at all because convection was entirely absent when either phenomenon was removed.
Further analysis reveals why both circulations were necessary yet not sufficient for the excitation of deep convection in this case. The sea-breeze circulation (SBC) made its upstream (inland) environment more favorable for convection by bringing about persistent if gentle lifting over an extended region stretching well ahead of the SBF. This persistent ascent established a moist and cool tongue of air, manifested by a visible and/or subvisible cloud feature termed the cloud shelf emanating ahead of the front. Though this lifting moistened and destabilized the environment, the roll’s direct and indirect effects on this moist tongue were also required. The former consisted of a moisture plume lofted by the roll updraft, and the latter consisted of obstacle effect gravity waves generated as the roll drafts penetrated through the top of the boundary layer, into the SBC-associated offshore flow farther aloft. These provided the missing spark, which led to rapid growth of cumulus above the roll updraft, drawing first from air located above the boundary layer.
Once established, deep convection above the roll updraft modulated cloudiness above the approaching SBF, at first suppressing it but subsequently assuring its reestablishment and eventual growth into deep convection, again prior to the front–roll merger. This resulted from the influence of gravity waves excited owing to heating and cooling within the roll cloud.
The Diurnal Cycle of Precipitation in the Tropical Andes of Colombia
Authors: Poveda Germán , Mesa Oscar J. , Salazar Luis F. , Arias Paola A. , Moreno Hernán A. , Vieira Sara C. , Agudelo Paula A. , Toro Vladimir G. , Alvarez J. Felipe 
Published: March 2005

Abstract
Using hourly records from 51 rain gauges, spanning between 22 and 28 yr, the authors study the diurnal cycle of precipitation over the tropical Andes of Colombia. Analyses are developed for the seasonal march of the diurnal cycle and its interannual variability during the two phases of El Niño–Southern Oscillation (ENSO). Also, the diurnal cycle is analyzed at intra-annual time scales, associated with the westerly and easterly phases of the Madden–Julian oscillation, as well as higher-frequency variability (&lt;10 days), mainly associated with tropical easterly wave activity during ENSO contrasting years. Five major general patterns are identified: (i) precipitation exhibits clear-cut diurnal (24 h) and semidiurnal (12 h) cycles; (ii) the minimum of daily precipitation is found during the morning hours (0900–1100 LST) regardless of season or location; (iii) a predominant afternoon peak is found over northeastern and western Colombia; (iv) over the western flank of the central Andes, precipitation maxima occur either near midnight, or during the afternoon, or both; and (v) a maximum of precipitation prevails near midnight amongst stations located on the eastern flank of the central Cordillera. The timing of diurnal maxima is highly variable in space for a fixed time, although a few coherent regions are found in small groups of rain gauges within the Cauca and Magdalena River valleys. Overall, the identified strong seasonal variability in the timing of rainfall maxima appears to exhibit no relationship with elevation on the Andes. The effects of both phases of ENSO are highly consistent spatially, as the amplitude of hourly and daily precipitation diminishes (increases) during El Niño (La Niña), but the phase remains unaltered for the entire dataset. We also found a generalized increase (decrease) in hourly and daily rainfall rates during the westerly (easterly) phase of the Madden–Julian oscillation, and a diminished (increased) high-frequency activity in July–October and February–April during El Niño (La Niña) years, associated, among others, with lower (higher) tropical easterly wave (4–6 day) activity over the Caribbean.
The 30 May 1998 Spencer, South Dakota, Storm. Part II: Comparison of Observed Damage and Radar-Derived Winds in the Tornadoes
Authors: Wurman Joshua , Alexander Curtis R. 
Published: March 2005

Abstract
A violent supercell tornado passed through the town of Spencer, South Dakota, on the evening of 30 May 1998 producing large gradients in damage severity. The tornado was rated at F4 intensity by damage survey teams. A Doppler On Wheels (DOW) mobile radar followed this tornado and observed the tornado at ranges between 1.7 and 8.0 km during various stages of the tornado's life. The DOW was deployed less than 4.0 km from the town of Spencer between 0134 and 0145 UTC, and during this time period, the tornado passed through Spencer, and peak Doppler velocity measurements exceeded 100 m s−1. Data gathered from the DOW during this time period contained high spatial resolution sample volumes of approximately 34 m × 34 m × 37 m along with frequent volume updates every 45–50 s.
The high-resolution Doppler velocity data gathered from low-level elevation scans, when sample volumes are between 20 and 40 m AGL, are compared to extensive ground and aerial damage surveys performed by the National Weather Service (NWS) and the National Institute of Standards and Technology (NIST). Idealized radial profiles of tangential velocity are computed by fitting a model of an axisymmetric translating vortex to the Doppler radar observations, which compensates for velocity components perpendicular to the radar beam as well as the translational motion of the tornado vortex.
Both the original single-Doppler velocity data and the interpolated velocity fields are compared with damage survey Fujita scale (F-scale) estimates throughout the town of Spencer. This comparison on a structure-by-structure basis revealed that radar-based estimates of the F-scale intensity usually exceeded the damage-survey-based F-scale both inside and outside the town of Spencer. In the town of Spencer, the radar-based wind field revealed two distinct velocity time series inside and outside the passage of the core-flow region. The center of the core-flow region tracked about 50 m farther north than the damage survey indicated because of the asymmetry induced by the 15 m s−1 translational motion of the tornado. The radar consistently measured the strongest winds in the lowest 200 m AGL with the most extreme Doppler velocities residing within 50 m AGL. Alternate measures of tornado wind field intensity that incorporated the effects of the duration of the extreme winds and debris were explored. It is suggested that damage may not be a simple function of peak wind gust and structural integrity, but that the duration of intense winds, directional changes, accelerations, and upwind debris loading may be critical factors.
A Local Energetics Analysis of the Life Cycle Differences between Consecutive, Explosively Deepening, Continental Cyclones
Authors: Decker Steven G. , Martin Jonathan E. 
Published: March 2005

Abstract
Local energetics diagnostics of the life cycles of consecutive, explosively deepening, extratropical cyclones that migrated across central North America in April 2001 are presented. Both storms developed rapidly and followed nearly identical tracks through the region. Despite similar mature-stage intensities, the two storms underwent vastly different evolutions during cyclolysis; the first decayed as rapidly as it had developed, and the second decayed very slowly. Examination of the volume-integrated eddy kinetic energy (EKE) budget for each storm reveals that the sea level pressure minimum associated with the first cyclone developed well after its associated EKE center had reached its maximum intensity. In contrast, the second cyclone’s sea level pressure minimum developed much more in concert with the development of its associated EKE center. As a consequence, the first cyclone began losing EKE through downstream energy fluxes even as it was developing at the surface, whereas the second cyclone did not disperse EKE downstream until later in its life cycle. Consideration of the EKE budget results in terms of baroclinic wave packets demonstrates that the first cyclone developed and decayed on the upstream edge of a wave packet, whereas the second cyclone developed in the midst of a wave packet, only decaying once it had reached the upstream edge. Thus, it is suggested that postmature phase decay is dynamically linked to a cyclone’s position in a given wave packet.
Incorporating State-Dependent Temperature–Salinity Constraints in the Background Error Covariance of Variational Ocean Data Assimilation
Authors: Ricci S. , Weaver A. T. , Vialard J. , Rogel P. 
Published: March 2005

Abstract
Several studies have illustrated how the univariate assimilation of temperature data can have a detrimental effect on the ocean-state variables (salinity, currents, etc.) not directly constrained by the data. In this paper, the authors describe how the salinity adjustment method proposed by Troccoli and Haines can be included as a multivariate temperature–salinity (T–S) constraint within a background-error covariance model for variational data assimilation. The method is applied to a three-dimensional variational assimilation (3DVAR) system for a tropical Pacific version of the Océan Parallélisé (OPA) ocean general circulation model. An identical twin experiment is presented first to illustrate how the method is effective in reconstructing a density profile using only temperature observations from that profile. The 3DVAR system is then cycled over the period 1993–98 using in situ temperature data from the Global Temperature and Salinity Pilot Programme. Relative to a univariate (T) 3DVAR, the multivariate (T, S) 3DVAR significantly improves the salinity mean state. A comparison with salinity data that are not assimilated is also presented. The fit to these observations is improved when the T–S constraint is applied. The salinity correction leads to a better preservation of the salinity structure and avoids the development of spurious geostrophic currents that were evident in the univariate analysis. The currents at the surface and below the core of the undercurrent are also improved.
Examination of the heat budget highlights how the temperature increment must compensate for a perpetual degradation of the temperature field by abnormally strong advection in the univariate experiment. When the T–S constraint is applied, this spurious advection is reduced and the mean temperature increment is decreased. Examination of the salt budget shows that spurious advection is also the main cause of the upper-ocean freshening. When the T–S constraint is applied, the salinity structure is improved allowing for a better representation of the advection term and better preservation of the salt content in the upper ocean. The T–S constraint does not correct for all problems linked to data assimilation: vertical mixing is still too strong, and the surface salinity state and currents still have substantial errors. Improvements can be expected by including additional constraints in the background error covariances and by assimilating salinity data.
Rapamycin selectively expands CD4+CD25+FoxP3+ regulatory T cells
Authors: Battaglia Manuela , Stabilini Angela , Roncarolo Maria-Grazia 
Published: March 2005

AbstractRapamycin is an immunosuppressive compound that is currently used to prevent acute graft rejection in humans. In addition, rapamycin has been shown to allow operational tolerance in murine models. However, a direct effect of rapamycin on T regulatory (Tr) cells, which play a key role in induction and maintenance of peripheral tolerance, has not been demonstrated so far. Here, we provide new evidence that rapamycin selectively expands the murine naturally occurring CD4+CD25+FoxP3+ Tr cells in vitro. These expanded Tr cells suppress proliferation of syngeneic T cells in vitro and prevent allograft rejection in vivo. Interestingly, rapamycin does not block activation-induced cell death and proliferation of CD4+ T cells in vitro. Based on this new mode of action, rapamycin can be used to expand CD4+CD25+FoxP3+ Tr cells for ex vivo cellular therapy in T-cell-mediated diseases. (Blood. 2005;105:4743-4748)
Telomere length as a prognostic parameter in chronic lymphocytic leukemia with special reference to VH gene mutation status
Authors: Grabowski Pawel , Hultdin Magnus , Karlsson Karin , Tobin Gerard , Åleskog Anna , Thunberg Ulf , Laurell Anna , Sundström Christer , Rosenquist Richard , Roos Göran 
Published: March 2005

AbstractB-cell chronic lymphocytic leukemia (CLL) consists of 2 prognostic entities where cases with mutated immunoglobulin VH genes have better outcome than unmutated cases. VH-mutated CLLs display longer telomeres compared with unmutated cases and telomere length has been indicated to predict outcome, although the prognostic value of telomere length has not been fully established in CLL. We analyzed telomere length, VH gene mutation status, and clinical parameters in a large series of CLL. Telomere length was assessed by quantitative polymerase chain reaction (PCR), giving a very good correlation to telomere length estimated by Southern blotting (P &lt; .001). The prognostic information given by mutation status (n = 282) and telomere length (n = 246) was significant (P &lt; .001, respectively). Telomere length was a prognostic factor for stage A (P = .021) and stage B/C (P = .018) patients, whereas mutation status predicted outcome only in stage A patients (P &lt; .001). Furthermore, mutated CLLs were subdivided by telomere length into 2 groups with different prognoses (P = .003), a subdivision not seen for unmutated cases (P = .232). Interestingly, the VH-mutated group with short telomeres had an overall survival close to that of the unmutated cases. Thus, by combining VH mutation status and telomere length, an improved subclassification of CLL was achieved identifying previously unrecognized patient groups with different outcomes. (Blood. 2005;105:4807-4812)