bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Airborne Profiling Radar Study of the Impact of Glaciogenic Cloud Seeding on Snowfall from Winter Orographic Clouds
Authors: Geerts Bart , Miao Qun , Yang Yang , Rasmussen Roy , Breed Daniel 
Published: June 2010

Abstract
Data from an airborne vertically pointing millimeter-wave Doppler radar are used to study the cloud microphysical effect of glaciogenic seeding of cold-season orographic clouds. Fixed flight tracks were flown downstream of ground-based silver iodide (AgI) generators in the Medicine Bow Mountains of Wyoming. Composite data from seven flights, each with a no-seeding period followed by a seeding period, indicate that radar reflectivity was higher near the ground during the seeding periods. Several physical considerations argue in favor of the hypothesis that the increase in near-surface reflectivity is attributed to AgI seeding. While the increase in near-surface reflectivity and thus snowfall rate are statistically significant, caution is warranted in view of the large natural variability of weather conditions and the small size of the dataset.
Genesis of Indian Ocean Mixed Layer Temperature Anomalies: A Heat Budget Analysis
Authors: Santoso Agus , Sen Gupta Alexander , England Matthew H. 
Published: June 2010

Abstract
The genesis of mixed layer temperature anomalies across the Indian Ocean are analyzed in terms of the underlying heat budget components. Observational data, for which a seasonal budget can be computed, and a climate model output, which provides improved spatial and temporal coverage for longer time scales, are examined. The seasonal climatology of the model heat budget is broadly consistent with the observational reconstruction, thus providing certain confidence in extending the model analysis to interannual time scales. To identify the dominant heat budget components, covariance analysis is applied based on the heat budget equation. In addition, the role of the heat budget terms on the generation and decay of temperature anomalies is revealed via a novel temperature variance budget approach. The seasonal evolution of the mixed layer temperature is found to be largely controlled by air–sea heat fluxes, except in the tropics where advection and entrainment are important. A distinct shift in the importance and role of certain heat budget components is shown to be apparent in moving from seasonal to interannual time scales. On these longer time scales, advection gains importance in generating and sustaining anomalies over extensive regions, including the trade wind and midlatitude wind regimes. On the other hand, air–sea heat fluxes tend to drive the evolution of thermal anomalies over subtropical regions including off northwestern Australia. In the tropics, however, they limit the growth of anomalies. Entrainment plays a role in the generation and maintenance of interannual anomalies over localized regions, particularly off Sumatra and over the Seychelles–Chagos Thermocline Ridge. It is further shown that the spatial distribution of the role and importance of these terms is related to oceanographic features of the Indian Ocean. Mixed layer depth effects and the influence of model biases are discussed.
Surface Heat Flux Variations across the Kuroshio Extension as Observed by Surface Flux Buoys
Authors: Konda Masanori , Ichikawa Hiroshi , Tomita Hiroyuki , Cronin Meghan F. 
Published: June 2010

Abstract
Wintertime sea surface heat flux variability across the Kuroshio Extension (KE) front is analyzed using data from the Kuroshio Extension Observatory (KEO) buoy in the Kuroshio recirculation gyre south of the KE front and from the Japan Agency for Marine–Earth Science and Technology KEO (JKEO) buoy in the north of the front. The coincident data used are from periods during two winters (2007 and 2008), when both buoys had a complete suite of meteorological data. In these two winter periods, the focus of this research is on three types of typical weather patterns referred to here as the northerly wind condition, the monsoon wind condition, and the normal condition. During the northerly wind condition, latent and sensible heat fluxes were large and often varied simultaneously at both sites, whereas during the monsoon wind condition the latent heat flux at the KEO site was significantly larger than that at the JKEO site. The difference between these heat flux patterns is attributed to the different airmass transformations that occur when prevailing winds blow across the KE front versus along the front. Reanalysis products appear to reproduce these heat flux spatial patterns at synoptic scales. It is suggested that the relative frequencies of these different types of weather conditions result in anomalous spatial patterns in the heat fluxes on monthly time scales.
Ensemble Construction and Verification of the Probabilistic ENSO Prediction in the LDEO5 Model
Authors: Cheng Yanjie , Tang Youmin , Jackson Peter , Chen Dake , Deng Ziwang 
Published: June 2010

Abstract
El Niño–Southern Oscillation (ENSO) retrospective ensemble-based probabilistic predictions were performed for the period of 1856–2003 using the Lamont-Doherty Earth Observatory, version 5 (LDEO5), model. To obtain more reliable and skillful ENSO probabilistic predictions, first, four ensemble construction strategies were investigated: (i) the optimal initial perturbation with singular vector of sea surface temperature anomaly (SSTA), (ii) the realistic high-frequency anomalous winds, (iii) the stochastic optimal pattern of anomalous winds, and (iv) a combination of the first and the third strategy. Second, verifications were conducted to examine the reliability and resolution of the probabilistic forecasts provided by the four methods. Results suggest that reliability of ENSO probabilistic forecast is more sensitive to the choice of ensemble construction strategy than the resolution, and a reliable and skillful ENSO probabilistic prediction system may not necessarily have the best deterministic prediction skills. Among these ensemble construction methods, the fourth strategy produces the most reliable and skillful ENSO probabilistic prediction, benefiting from the joint contributions of the stochastic optimal winds and the singular vector of SSTA. In particular, the stochastic optimal winds play an important role in improving the ENSO probabilistic predictability for the LDEO5 model.
Persistence of Easterly Wind during Major Stratospheric Sudden Warmings
Authors: Tomikawa Yoshihiro 
Published: June 2010

Abstract
This study examines why the persistence of easterly wind during major stratospheric sudden warmings (SSWs) varies from one SSW to another. From the 22 SSWs identified between 1979 and 2009, six long and six short SSWs of easterly wind periods longer than 20 days and shorter than 10 days, respectively, are chosen and their composites are compared. While the polar-night jet is stronger than the climatological jet before long SSWs, the preconditioning of the polar-night jet tends to occur before short SSWs. After the occurrence of SSWs, the easterly wind of short SSWs quickly returns to a westerly wind due to large positive Eliassen–Palm (E–P) flux divergence in the winter polar stratosphere. The easterly wind of long SSWs lasts for 20–40 days because the E–P flux divergence is small whether it is positive or negative. Such a difference in the E–P flux divergence originates from the difference in the upward E–P flux from the troposphere. On the other hand, the positive E–P flux divergence during short SSWs is not caused by the variation of upward E–P flux from the troposphere but could be due to the shear instability caused by the overreflection of zonal wavenumber 1 planetary waves at the critical surface. The difference in the persistence of easterly wind between long and short SSWs also has a large impact on the planetary wave activity in the winter stratosphere.
Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data
Authors: Yuan Jian , Houze Robert A. 
Published: June 2010

AbstractMesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-train satellite instruments: Moderate Resolution Imaging Spectroradiometer (MODIS) for cloud-top size and coldness, Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) for rain area size and intensity, and CloudSat for horizontal and vertical dimensions of anvils. The authors distinguish three types of MCSs: small and large separated MCSs and connected MCSs. The latter are MCSs sharing a contiguous rain area. Mapping of the objectively identified MCSs shows patterns of MCSs that are consistent with previous studies of tropical convection, with separated MCSs dominant over Africa and the Amazon regions and connected MCSs favored over the warm pool of the Indian and west Pacific Oceans.By separating the anvil from the raining regions of MCSs, this study leads to quantitative global maps of anvil coverage. These maps are consistent with the MCS analysis, and they lay the foundation for estimating the global radiative effects of anvil clouds.CloudSat radar data show that the modal thickness of MCS anvils is ∼4–5 km. Anvils are mostly confined to within 1.5–2 times the equivalent radii of the primary rain areas of the MCSs. Over the warm pool, they may extend out to ∼5 times the rain area radii. The warm ocean MCSs tend to have thicker nonraining and lightly raining anvils near the edges of their actively raining regions, indicating that anvils are generated in and spread out from the primary raining regions of the MCSs. Thicker anvils are nearly absent over continental regions.
Momentum Flux Budget across the Air–Sea Interface under Uniform and Tropical Cyclone Winds
Authors: Fan Yalin , Ginis Isaac , Hara Tetsu 
Published: June 2010

Abstract
In coupled ocean–atmosphere models, it is usually assumed that the momentum flux into ocean currents is equal to the flux from air (wind stress). However, when the surface wave field grows (decays) in space or time, it gains (loses) momentum and reduces (increases) the momentum flux into subsurface currents compared to the flux from the wind. In particular, under tropical cyclone (TC) conditions the surface wave field is complex and fast varying in space and time and may significantly affect the momentum flux from wind into ocean. In this paper, numerical experiments are performed to investigate the momentum flux budget across the air–sea interface under both uniform and idealized TC winds. The wave fields are simulated using the WAVEWATCH III model. The difference between the momentum flux from wind and the flux into currents is estimated using an air–sea momentum flux budget model. In many of the experiments, the momentum flux into currents is significantly reduced relative to the flux from the wind. The percentage of this reduction depends on the choice of the drag coefficient parameterization and can be as large as 25%. For the TC cases, the reduction is mainly in the right-rear quadrant of the hurricane, and the percentage of the flux reduction is insensitive to the changes of the storm size and the asymmetry in the wind field but varies with the TC translation speed and the storm intensity. The results of this study suggest that it is important to explicitly resolve the effect of surface waves for accurate estimations of the momentum flux into currents under TCs.
The Obduction of Equatorial 13°C Water in the Pacific Identified by a Simulated Passive Tracer*
Authors: Qu Tangdong , Gao Shan , Fukumori Ichiro , Fine Rana A. , Lindstrom Eric J. 
Published: June 2010

Abstract
The obduction of equatorial 13°C Water in the Pacific is investigated using a simulated passive tracer of the Consortium for Estimating the Circulation and Climate of the Ocean (ECCO). The result shows that the 13°C Water initialized in the region 8°N–8°S, 130°–90°W enters the surface mixed layer in the eastern tropical Pacific, mainly through upwelling near the equator, in the Costa Rica Dome, and along the coast of Peru. Approximately two-thirds of this obduction occurs within 10 years after the 13°C Water being initialized, with the upper portion of the water mass reaching the surface mixed layer in only about a month. The obduction of the 13°C Water helps to maintain a cool sea surface temperature year-round, equivalent to a surface heat flux of about −6.0 W m−2 averaged over the eastern tropical Pacific (15°S–15°N, 130°W–eastern boundary) for the period of integration (1993–2006). During El Niño years, when the thermocline deepens as a consequence of the easterly wind weakening, the obduction of the 13°C Water is suppressed, and the reduced vertical entrainment generates a warming anomaly of up to 10 W m−2 in the eastern tropical Pacific and in particular along the coast of Peru, providing explanations for the warming of sea surface temperature that cannot be accounted for by local winds alone. The situation is reversed during La Niña years.
Toward a Midlatitude Ocean Frequency–Wavenumber Spectral Density and Trend Determination
Authors: Wunsch Carl 
Published: June 2010

Abstract
The time- and space-scale descriptive power of two-dimensional Fourier analysis is exploited to reanalyze the behavior of midlatitude variability as seen in altimetric data. These data are used to construct a purely empirical and analytical frequency–zonal wavenumber spectrum of ocean variability for periods between about 20 days and 15 yr and on spatial scales of about 200–10 000 km. The spectrum is dominated by motions along a “nondispersive” line, which is a robust feature of the data but for whose prominence a complete theoretical explanation is not available. The estimated spectrum also contains significant energy at all frequencies and wavenumbers in this range, including eastward-propagating motions, which are likely some combination of nonlinear spectral cascades, wave propagation, and wind-forced motions. The spectrum can be used to calculate statistical expectations of spatial average sea level and transport variations. However, because the statistics of trend determination in quantities such as sea level and volume transports depend directly upon the spectral limit of the frequency approaching zero, the appropriate significance calculations remain beyond reach, because low-frequency variability is indistinguishable from trends already present in the data.
Evaluation of Surface Temperature and Emissivity Derived from ASTER Data: A Case Study Using Ground-Based Measurements at a Volcanic Site
Authors: Barreto África , Arbelo Manuel , Hernández-Leal Pedro A. , Núñez-Casillas Laia , Mira María , Coll César 
Published: June 2010

Abstract
The land surface temperature (LST) and emissivity (LSE) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were evaluated in a low spectral contrast volcanic site at an altitude of 2000 m on the island of Tenerife, Spain. The test site is almost flat, thermally homogeneous, and without vegetation cover or variation in its surface composition. ASTER data correspond to six scenes, under both day- and nighttime conditions during 2008. This case study analyzes the impacts of the sources of inaccuracies using the temperature–emissivity separation (TES) algorithm. Uncertainties associated with inaccurate atmospheric correction were minimized by means of local soundings and the climate advantages of the area.
Concurrent ground-based radiometric measurements were performed for LST, and laboratory and field measurements for LSE, to obtain reference values. The TES evaluation showed a good level of agreement in the emissivity derived for ASTER bands 13 and 14 [root-mean-square difference (RMSD) lower than 0.002] and discrepancies in ASTER bands 10 and 11 that were within the expected performance of the algorithm (±0.015). However, out-of-threshold errors were retrieved in band 12, producing an artificial increase in spectral contrast. The underestimated TES LSE spectra point to the presence of a roughness effect at measurement scales that may increase the laboratory band emissivity values. TES LST comparison with ground data showed an RMSD value of 0.5 K. ASTER standard products AST08 (LST) and AST05 (LSE) atmospherically corrected by means of Naval Research Laboratory (NRL) data were also tested, showing a similar level of performance for the TES implemented with local soundings, but failed in high-humidity atmospheric conditions.
A Revised Model for Radial Profiles of Hurricane Winds
Authors: Holland Greg J. , Belanger James I. , Fritz Angela 
Published: June 2010

Abstract
A revision to the Holland parametric approach to modeling the radial profile of winds in hurricanes is presented. The approach adopted uses information readily available from hurricane archives or in hurricane warning information and the profile can be readily incorporated into existing parametric models of the hurricane surface wind field. The original model utilized central and environmental surface pressures, maximum winds, and radius of maximum winds. In the revision a capacity to incorporate additional wind observations at some radius within the hurricane circulation was included. If surface observations are used, then a surface wind profile will result, obviating the need for deriving a boundary layer reduction from the gradient wind level. The model has considerably less sensitivity to data errors compared to the original and is shown to reproduce hurricane reconnaissance and surface wind profiles with high accuracy.
Rapid Intensification of a Sheared Tropical Storm
Authors: Molinari John , Vollaro David 
Published: June 2010

Abstract
A weak tropical storm (Gabrielle in 2001) experienced a 22-hPa pressure fall in less than 3 h in the presence of 13 m s−1 ambient vertical wind shear. A convective cell developed downshear left of the center and moved cyclonically and inward to the 17-km radius during the period of rapid intensification. This cell had one of the most intense 85-GHz scattering signatures ever observed by the Tropical Rainfall Measuring Mission (TRMM). The cell developed at the downwind end of a band in the storm core. Maximum vorticity in the cell exceeded 2.5 × 10−2 s−1. The cell structure broadly resembled that of a vortical hot tower rather than a supercell.
At the time of minimum central pressure, the storm consisted of a strong vortex adjacent to the cell with a radius of maximum winds of about 10 km that exhibited almost no tilt in the vertical. This was surrounded by a broader vortex that tilted approximately left of the ambient shear vector, in a similar direction as the broad precipitation shield. This structure is consistent with the recent results of Riemer et al.
The rapid deepening of the storm is attributed to the cell growth within a region of high efficiency of latent heating following the theories of Nolan and Vigh and Schubert. This view is supported by a rapid growth of wind speed and vorticity in the storm core during the 1-h lifetime of the cell, and by the creation of a narrow 7°C spike in 700-hPa temperature adjacent to the cell and coincident with the lowest pressure. The cell is not seen as the cause of rapid intensification. Rather, it is part of a multiscale process: (i) development of a new circulation center within the downshear precipitation shield, (ii) continued ambient shear creating a favored region for cell formation just downshear of the new center, and (iii) the development of the intense cell that enhanced diabatic heating close to the center in a region of high efficiency of kinetic energy production. This sheared, asymmetric rapid intensification of Tropical Storm Gabrielle is contrasted with the nearly symmetric composite given by Kaplan and DeMaria.
Characteristics of Summer Trade Wind Rainfall over Oahu
Authors: Hartley Treena Marie , Chen Yi-Leng 
Published: June 2010

Abstract
In this study, characteristics of summer trade wind rainfall over Oahu, Hawaii, are analyzed. In the early morning before sunrise, flow deceleration on the windward coastal area is the greatest when the island land surface is the coldest. Furthermore, relatively calm winds are found over central Oahu between the Ko’olau Mountains and the Waianae Mountains, with weak westerly katabatic winds on the windward side of the Waianae Mountains. Most windward stations have an early morning rainfall maximum with a secondary rainfall maximum in the early evening. Morning (afternoon) land (sea) breezes dominate under variable winds, and are more pronounced over leeward Oahu. Precipitation on the western leeside coast has a slight peak in the afternoon due to an increase of cloud development from the afternoon sea breezes. Daily orographic rainfall over Oahu is greater under the strong trade wind regime, and less under weak trade wind and variable-wind flow regimes. However, the maximum correlation between daily trade wind rainfall and trade wind speed is &lt;0.3. Days with high rainfall generally occur under strong trades, but not all strong trade wind days produce significant rainfall. With its relatively low terrain height compared to lifted condensation level (LCL) and relatively small size, orographic lifting alone is inadequate to initiate precipitation through warm rain processes. The existence of trade wind cumuli upstream is necessary. In addition, a deeper moist layer and higher moisture content upstream are two conditions that are favorable for higher orographic precipitation over Oahu under undisturbed summertime trade wind weather.
Weather, Climate, and Environmental Water Transactions
Authors: Jones Lana , Colby Bonnie 
Published: June 2010

Abstract
Obtaining water for environmental purposes, such as habitat restoration or water quality improvements, has become an important objective in many parts of the world. Such water acquisitions are likely to become more challenging as regional water demand and supply patterns are altered by climate change. In regions where water supplies are already fully claimed, voluntary negotiated transactions have become a key means to obtain water for the environment. The cost of acquiring water in such transactions is hypothesized to vary with regional weather and climate conditions due to both the actual effects of temperature and precipitation on water supply and demand and the perceptions water users may hold about these effects.
This article develops econometric models to examine the effect of temperature and precipitation on water lease prices in four U.S. states located in the desert southwest. Water leases for environmental and nonenvironmental purposes are contrasted to understand the differing nature of these lease markets and the role of weather and climate variables. The authors’ analysis finds that temperature, precipitation, regional income, and population changes are variables that have differing effects in the two lease markets. Overall, analysis of over 20 yr of data shows the need to consider climate and weather factors given the growing importance of water leases as a tool to secure water for the environment.