bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Acceleration of Large Water Drops to Terminal Velocity
Authors: Beard K. V. 
Published: March 2011

AbstractA theory based on the distortion of large water drops is used to calculate the drag and acceleration ofdrops in the laboratory from rest to terminal velocity. The results show that the drag coefficient curve foreach drop size lies between the curves for a sphere and for water drops at terminal velocity. A comparisonwith experimental acceleration data at sea level shows an improvement over the more approximate theoryof Wang and Pruppacher. The calculations of drops accelerating at reduced air density provide a very goodfit to the data of Davies at the reported fall distance of 11m. This new interpretation of Davies' experimentis consistent with the formula of Beard for the terminal velocity of large drops aloft.
ENVIRONMENTAL AND THUNDERSTORM STRUCTURES AS SHOWN BY NATIONAL SEVERE STORMS PROJECT OBSERVATIONS IN SPRING 1960 AND 1961
Authors: STAFF MEMBERS  
Published: March 2011

Abstract
Some examples of National Severe Storms Project observations are described, showing certain typical structures of the mesoscale environment and of large thunderstorms in the Oklahoma-Texas-Kansas region.
The “dry-line” at the cT/mT boundary is shown to be characterized by an extremely abrupt gradient of water-vapor content and temperature, accompanied by a wind-shift zone with appreciable horizontal convergence. On the moist air side, there were pronounced wavelike perturbations in the moisture and temperature fields, connected with systematic variations of the vector wind velocity.
Special pilot-balloon observations show the low-level jet as a flat sheet of southerly winds, with maximum strength generally 300 to 500 m. above ground, and illustrate the great variations of wind speed associated with diurnal variability of stability in the surface layers. Appreciable streakiness of the velocity field is indicated by both pibal and aircraft measurements.
A description is given of a series of intense low-pressure systems observed at the surface, in association with the northwest sides of radar echoes. These depressions, which form at night, are warm and very dry relative to their surroundings, and are attended by strong, gusty surface winds.
High-level aircraft observations are illustrated, demonstrating particularly the significant disturbances of the wind field around cloud tops. An example of gust measurements in the upper portion of a thunderstorm (imbedded in strong vertical shear) shows that the lateral gust components, up to 30 m./sec., are of the same order as the vertica1 gusts.
Movements of thunderstorms as shown by radar, and certain aspects of the reflectivities of tornado-bearing storms, are discussed briefly. Finally, the three-dimensional forms of large thunderstorms are illustrated, with emphasis on the organized asymmetrical structures.
Seasonal Changes in a Vertical Thermal Structure Producing Stable Lower-Troposphere Layers over the Inland Region of the Indochina Peninsula
Authors: Nodzu Masato I. , Ogino Shin-Ya , Yamanaka Manabu D. 
Published: March 2011

Abstract
The authors performed a thermal budget analysis to understand the nature of seasonal changes in stable lower-troposphere layers over the inland region of the Indochina Peninsula, using atmospheric reanalysis data. The analysis focuses on subseasonal stable layers. Stability increase in the generation of stable layers is classified into three dominant thermal factors: vertical differences in horizontal potential temperature advection, vertical potential temperature advection, and their residual component Q1. The largest contributor to the stability increase is defined as the dominant thermal factor. Climatological typical heights where stable layers most frequently appear are the 850–700-, 700–600-, and 600–500-hPa levels in November–January, February–March, and April, respectively, according to a previous study. From November to January, most of the stable layers in the typical height are generated by vertical differences in horizontal potential temperature advection. Their generation (dissipation) is characterized by strong (weak) cooling due to horizontal advection below the stable layers. The strong cooling is related to cold surges in the winter monsoon. Generation of the stable layers in the typical height from February to April is characterized by vertical differences in Q1. Here, Q1 cooling below the stable layers is demonstrated in February and March. The authors propose a mixed boundary layer process in explaining the Q1 cooling. In April, the analyses demonstrate Q1 heating above the stable layers, coincident with a peak in the apparent moisture sink. The results indicate that the thermal processes of stable-layer generation change the height of the stable layer along the seasonal advance.
Multimodel Estimate of the Global Terrestrial Water Balance: Setup and First Results
Authors: Haddeland Ingjerd , Clark Douglas B. , Franssen Wietse , Ludwig Fulco , Voß Frank , Arnell Nigel W. , Bertrand Nathalie , Best Martin , Folwell Sonja , Gerten Dieter , Gomes Sandra , Gosling Simon N. , Hagemann Stefan , Hanasaki Naota , Harding Richard , Heinke Jens , Kabat Pavel , Koirala Sujan , Oki Taikan , Polcher Jan , Stacke Tobias , Viterbo Pedro , Weedon Graham P. , Yeh Pat 
Published: March 2011

AbstractSix land surface models and five global hydrological models participate in a model intercomparison project [Water Model Intercomparison Project (WaterMIP)], which for the first time compares simulation results of these different classes of models in a consistent way. In this paper, the simulation setup is described and aspects of the multimodel global terrestrial water balance are presented. All models were run at 0.5° spatial resolution for the global land areas for a 15-yr period (1985–99) using a newly developed global meteorological dataset. Simulated global terrestrial evapotranspiration, excluding Greenland and Antarctica, ranges from 415 to 586 mm yr−1 (from 60 000 to 85 000 km3 yr−1), and simulated runoff ranges from 290 to 457 mm yr−1 (from 42 000 to 66 000 km3 yr−1). Both the mean and median runoff fractions for the land surface models are lower than those of the global hydrological models, although the range is wider. Significant simulation differences between land surface and global hydrological models are found to be caused by the snow scheme employed. The physically based energy balance approach used by land surface models generally results in lower snow water equivalent values than the conceptual degree-day approach used by global hydrological models. Some differences in simulated runoff and evapotranspiration are explained by model parameterizations, although the processes included and parameterizations used are not distinct to either land surface models or global hydrological models. The results show that differences between models are a major source of uncertainty. Climate change impact studies thus need to use not only multiple climate models but also some other measure of uncertainty (e.g., multiple impact models).
Impact of a Statistical Bias Correction on the Projected Hydrological Changes Obtained from Three GCMs and Two Hydrology Models
Authors: Hagemann Stefan , Chen Cui , Haerter Jan O. , Heinke Jens , Gerten Dieter , Piani Claudio 
Published: March 2011

Abstract
Future climate model scenarios depend crucially on the models’ adequate representation of the hydrological cycle. Within the EU integrated project Water and Global Change (WATCH), special care is taken to use state-of-the-art climate model output for impacts assessments with a suite of hydrological models. This coupling is expected to lead to a better assessment of changes in the hydrological cycle. However, given the systematic errors of climate models, their output is often not directly applicable as input for hydrological models. Thus, the methodology of a statistical bias correction has been developed for correcting climate model output to produce long-term time series with a statistical intensity distribution close to that of the observations. As observations, global reanalyzed daily data of precipitation and temperature were used that were obtained in the WATCH project. Daily time series from three GCMs (GCMs) ECHAM5/Max Planck Institute Ocean Model (MPI-OM), Centre National de Recherches Météorologiques Coupled GCM, version 3 (CNRM-CM3), and the atmospheric component of the L’Institut Pierre-Simon Laplace Coupled Model, version 4 (IPSL CM4) coupled model (called LMDZ-4)—were bias corrected. After the validation of the bias-corrected data, the original and the bias-corrected GCM data were used to force two global hydrology models (GHMs): 1) the hydrological model of the Max Planck Institute for Meteorology (MPI-HM) consisting of the simplified land surface (SL) scheme and the hydrological discharge (HD) model, and 2) the dynamic global vegetation model called LPJmL. The impact of the bias correction on the projected simulated hydrological changes is analyzed, and the simulation results of the two GHMs are compared. Here, the projected changes in 2071–2100 are considered relative to 1961–90. It is shown for both GHMs that the usage of bias-corrected GCM data leads to an improved simulation of river runoff for most catchments. But it is also found that the bias correction has an impact on the climate change signal for specific locations and months, thereby identifying another level of uncertainty in the modeling chain from the GCM to the simulated changes calculated by the GHMs. This uncertainty may be of the same order of magnitude as uncertainty related to the choice of the GCM or GHM. Note that this uncertainty is primarily attached to the GCM and only becomes obvious by applying the statistical bias correction methodology.
Propagating Subsurface Uncertainty to the Atmosphere Using Fully Coupled Stochastic Simulations
Authors: Williams John L. , Maxwell Reed M. 
Published: March 2011

AbstractFeedbacks between the land surface and the atmosphere, manifested as mass and energy fluxes, are strongly correlated with soil moisture, making soil moisture an important factor in land–atmosphere interactions. It is shown that a reduction of the uncertainty in subsurface properties such as hydraulic conductivity (K) propagates into the atmosphere, resulting in a reduction in uncertainty in land–atmosphere feedbacks that yields more accurate atmospheric predictions. Using the fully coupled groundwater-to-atmosphere model ParFlow-WRF, which couples the hydrologic model ParFlow with the Weather Research and Forecasting (WRF) atmospheric model, responses in land–atmosphere feedbacks and wind patterns due to subsurface heterogeneity are simulated. Ensembles are generated by varying the spatial location of subsurface properties while maintaining the global statistics and correlation structure. This approach is common to the hydrologic sciences but uncommon in atmospheric simulations where ensemble forecasts are commonly generated with perturbed initial conditions or multiple model parameterizations. It is clearly shown that different realizations of K produce variation in soil moisture, latent heat flux, and wind for both point and domain-averaged quantities. Using a single random field to represent a control case, varying amounts of K data are sampled and subsurface data are incorporated into conditional Monte Carlo ensembles to show that the difference between the ensemble mean prediction and the control saturation, latent heat flux, and wind speed are reduced significantly via conditioning of K. By reducing uncertainty associated with land–atmosphere feedback mechanisms, uncertainty is also reduced in both spatially distributed and domain-averaged wind speed magnitudes, thus improving the ability to make more accurate forecasts, which is important for many applications such as wind energy.
Multiday Circulation and Precipitation Climatology during Winter Rain Events of Differing Intensities in Central Chile
Authors: Barrett Bradford S. , Krieger Dominique Bastine , Barlow Caroline P. 
Published: March 2011

AbstractThe majority of precipitation in central Chile falls during austral winter with the passage of surface and upper-level low pressure systems and their associated surface fronts. Earlier studies have found the presence of a terrain-parallel, low-level barrier jet during cold front passage and low-level wind convergence in the region of heaviest precipitation. This study advances these findings by developing multiyear climatologies for a rainfall event in central Chile using a broad cross section of observational datasets: the Tropical Rainfall Measuring Mission (TRMM), the Atmospheric Infrared Sounder (AIRS), the National Climatic Data Center (NCDC) Global Surface Summary of the Day (GSOD), the Integrated Global Radiosonde Archive (IGRA), the Quick Scatterometer (QuikSCAT), and the NCEP–NCAR reanalysis. For this study, a precipitation event was defined as daily rainfall exceeding a certain threshold at a Santiago observing station (Pudahuel). Climatologies were developed for a five-day period surrounding the precipitation event: the three days leading up to the day of precipitation at Pudahuel, the day of the precipitation itself, and the day after. Precipitation was found to move northeastward over the southeast Pacific toward central Chile and increase in intensity upon reaching reached the coast between 33° and 40°S. At middle levels, a pronounced 500-hPa trough moved eastward and amplified during the same period, and at the surface, an area of low pressure deepened and followed the same path to the east. In the boundary layer and lower troposphere, winds at 925 and 850 hPa became exclusively north-northwesterly, suggesting the existence of a low-level jet, and surface winds backed with time and increased in speed ahead of a well-defined cold front wind shift. As these winds became more northwesterly ahead of the upper-level trough and surface low, precipitable water values increased, and a tongue of high precipitable water air intersected the coast at the same location as the region of heaviest precipitation. These climatologies, based on hundreds of cases, together provide strong confirmation that forcing associated with an eastward-progressing upper-level trough, a terrain-parallel low-level wind maximum, and an advancing surface cold front together constitute the complex, complementary mechanisms for precipitation in central Chile.
Estimating Potential Evaporation from Vegetated Surfaces for Water Management Impact Assessments Using Climate Model Output
Authors: Bell Victoria A. , Gedney Nicola , Kay Alison L. , Smith Roderick N. B. , Jones Richard G. , Moore Robert J. 
Published: March 2011

AbstractRiver basin managers concerned with maintaining water supplies and mitigating flood risk in the face of climate change are taking outputs from climate models and using them in hydrological models for assessment purposes. While precipitation is the main output used, evaporation is attracting increasing attention because of its significance to the water balance of river basins. Climate models provide estimates of actual evaporation that are consistent with their simplified land surface schemes but do not naturally provide the estimates of potential evaporation (PE) commonly required as input to hydrological models. There are clear advantages in using PE estimates controlled by atmospheric forcings when using stand-alone hydrological models with integral soil-moisture accounting schemes. The atmosphere–land decoupling approximation that PE provides can prove to be of further benefit if it is possible to account for the effect of different, or changing, land cover on PE outside of the climate model. The methods explored here estimate Penman–Monteith PE from vegetated surfaces using outputs from climate models that have an embedded land surface scheme. The land surface scheme enables an examination of the dependence of canopy stomatal resistance on atmospheric composition, and the sensitivity of PE estimates to the choice of canopy resistance values under current and changing climates is demonstrated. The conclusions have practical value for climate change impact studies relating to flood, drought, and water management applications.
Profiling Float Observations of the Upper Ocean under Sea Ice off the Wilkes Land Coast of Antarctica
Authors: Wong Annie P. S. , Riser Stephen C. 
Published: March 2011

Abstract
Multiyear under-ice temperature and salinity data collected by profiling floats are used to study the upper ocean near the Wilkes Land coast of Antarctica. The study region is in the seasonal sea ice zone near the southern terminus of the Antarctic Circumpolar Current. The profiling floats were equipped with an ice-avoidance algorithm and had a survival rate of 74% after 2.5 yr in the ocean. The data show that, in this part of Antarctica, the rate of sea ice decay exceeds the rate of sea ice growth. During the sea ice growth period, the water column is weakly stratified because of brine rejection and is only marginally stable. The average winter mixed layer temperature is about 0.12°C above the surface freezing point, providing evidence of entrainment of warmer water from the permanent pycnocline. The average mixed layer salinity increases by 0.127 from June to October. A one-dimensional model is used to quantify evolution of the winter mixed layer under a sea ice cover. The local winter entrainment rate is estimated to be 49 ± 11 m over 5 months, supplying a heat flux of 34 ± 8 W m−2 to the base of the mixed layer in winter. Model output gives a thermodynamic sea ice growth of 28 ± 15 cm over the same period. The winter ocean–atmosphere heat loss through leads and sea ice is estimated to be 14–25 W m−2 in this area, which is broadly in line with other winter observations from the East Antarctic region.
Vortex Merger in Oceanic Tripoles
Authors: Rodríguez-Marroyo Rocío , Viúdez Álvaro , Ruiz Simon 
Published: March 2011

Abstract
A new type of vortex merger is experimentally reported and numerically investigated. The merging process of two anticyclones under the influence of a cyclone (a three-vortex interaction) was observed in sea surface height (SSH) altimetry maps south of the Canary Islands. This three-vortex interaction is investigated using a process-oriented three-dimensional (3D), Boussinesq, and f-plane numerical model that explicitly conserves potential vorticity (PV) on isopycnals. The initial conditions consist of three static and inertially stable baroclinic vortices: two anticyclones and one cyclone. The vortex cores form a triangle in a configuration similar to that found south of the Canary Islands. The numerical results show, in agreement with SSH observations, that two corotating vortices, sufficiently close to each other and in presence of a third counterrotating vortex, merge, leading to a new elongated vortex, which couples with the counterrotating vortex, forming a dipole. Thus, the merging process occurred south of the Canary Islands is consistent with simplified vortex dynamics (basically PV conservation). The merging process depends on the initial PV density extrema, vertical extent, and the angle spanned by the corotating vortices. It is found that the presence of the third counterrotating vortex importantly affects the critical angle of merger and the processes of axisymmetrization and filamentation associated with the two corotating merging vortices. The torque exerted by the counterrotating vortex on the two corotating vortices delays, but does not prevent, their merger.
Estimate of the Predictability of Boreal Summer and Winter Intraseasonal Oscillations from Observations
Authors: Ding Ruiqiang , Li Jianping , Seo Kyong-Hwan 
Published: March 2011

AbstractTropical intraseasonal variability (TISV) shows two dominant modes: the boreal winter Madden–Julian oscillation (MJO) and the boreal summer intraseasonal oscillation (BSISO). The two modes differ in intensity, frequency, and movement, thereby presumably indicating different predictabilities. This paper investigates differences in the predictability limits of the BSISO and the boreal winter MJO based on observational data. The results show that the potential predictability limit of the BSISO obtained from bandpass-filtered (30–80 days) outgoing longwave radiation (OLR), 850-hPa winds, and 200-hPa velocity potential is close to 5 weeks, comparable to that of the boreal winter MJO. Despite the similarity between the potential predictability limits of the BSISO and MJO, the spatial distribution of the potential predictability limit of the TISV during summer is very different from that during winter. During summer, the limit is relatively low over regions where the TISV is most active, whereas it is relatively high over the North Pacific, North Atlantic, southern Africa, and South America. The spatial distribution of the limit during winter is approximately the opposite of that during summer. For strong phases of ISO convection, the initial error of the BSISO shows a more rapid growth than that of the MJO. The error growth is rapid when the BSISO and MJO enter the decaying phase (when ISO signals are weak), whereas it is slow when convection anomalies of the BSISO and MJO are located in upstream regions (when ISO signals are strong).
Laser Stapedotomy Minus Prosthesis
Authors: Silverstein Herbert , Van Ess Mark J. , Alameda Yadiel A. 
Published: March 2011

ObjectiveTo evaluate long‐term hearing results following laser stapedotomy minus prosthesis (laser STAMP).Study DesignCase series with chart review.SettingOtologic referral center.Subjects and MethodsFrom April 1995 to April 2009, 74 adult patients (77 ears; consecutive cases) underwent primary laser STAMP for otosclerosis limited to the fissula ante fenestram. Pure‐tone air, bone conduction thresholds, and word discrimination scores were obtained preoperatively, 1 month postoperatively, and yearly thereafter.ResultsOne‐year minimum follow‐up data were available for 43 patients (44 ears; nonconsecutive cases). The average air‐bone gap (ABG) was closed from a mean of 23 dB to 6 dB at 6 weeks postoperatively. At a median of 33 (lower quartile, 20; upper quartile 46; range, 12‐140) months postoperatively, the mean ABG was 7 dB, indicating little evidence of refixation. Seven of 77 patients (9%) underwent revision surgery with stapedotomy and placement of prosthesis with good results. Four patients (5%) were revised within 1 year for other problems unrelated to stapes refixation. Refixation was noted in 3 patients (4%) undergoing revision surgery. Two of these patients (3%) were revised within 1 year, and 1 patient (1%) was revised after 12 years.ConclusionsThe laser STAMP is a minimally invasive procedure resulting in stable long‐term hearing improvement in those patients available for long‐term follow‐up. Success depends on proper candidate selection of patients with accessible anatomy and minimal otosclerosis confined to the fissula ante fenestram. Advantages of this procedure include preservation of stapes anatomy and stable long‐term, high‐frequency hearing improvement.