检索结果-内蒙古大学图书馆

Community Global Observing System Simulation Experiment (OSSE) Package (CGOP): Description and Usage

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第8期33卷 1759-1777页

作者： Boukabara, Sid-Ahmed Moradi, Isaac Atlas, Robert Casey, Sean P. F. Cucurull, Lidia Hoffman, Ross N. Ide, Kayo Kumar, V. Krishna Li, Ruifang Li, Zhenglong Masutani, Michiko Shahroudi, Narges Woollen, Jack Zhou, Yan NOAA NESDIS Ctr Satellite Applicat & Res STAR College Pk MD 20740 USA Joint Ctr Satellite Data Assimilat College Pk MD 20742 USA Univ Maryland Cooperat Inst Climate & Satellites College Pk MD 20742 USA NOAA Atlantic Oceanog & Meteorol Lab Miami FL 33149 USA Univ Miami Cooperat Inst Marine & Atmospher Studies Miami FL 33152 USA NOAA Earth Syst Res Lab Global Syst Div Boulder CO 80303 USA Riverside Technol Inc Silver Spring MD USA Univ Colorado Cooperat Inst Res Environm Sci Boulder CO 80309 USA Univ Wisconsin Cooperat Inst Meteorol Satellite Studies Madison WI 53705 USA NOAA Natl Ctr Environm Predict College Pk MD 20740 USA NOAA Off Assistant Secretary Commerce Environm Observa Washington DC 20233 USA

A modular extensible framework for conducting observing system simulation experiments (OSSEs) has been developed with the goals of 1) supporting decision-makers with quantitative assessments of proposed observing systems investments, 2) supporting readiness for new sensors, 3) enhancing collaboration across the community by making the most up-to-date OSSE components accessible, and 4) advancing the theory and practical application of OSSEs. This first implementation, the Community Global OSSE Package (CGOP), is for short- to medium-range global numerical weather prediction applications. The CGOP is based on a new mesoscale global nature run produced by NASA using the 7-km cubed sphere version of the Goddard Earth Observing System, version 5 (GEOS-5), atmospheric general circulation model and the January 2015 operational version of the NOAA global data assimilation (DA) system. CGOP includes procedures to simulate the full suite of observing systems used operationally in the global DA system, including conventional in situ, satellite-based radiance, and radio occultation observations. The methodology of adding a new proposed observation type is documented and illustrated with examples of current interest. The CGOP is designed to evolve, both to improve its realism and to keep pace with the advance of operational systems.

关键词： Atm/Ocean Structure/ Phenomena Data assimilation Microwave observations Models and modeling observational techniques and algorithms Occultation Satellite observations Tropical cyclones

来源：评论

学校读者我要写书评

暂无评论

The Tornadic Supercell on the Kanto Plain on 6 May 2012: Polarimetric Radar and Surface Data Assimilation with EnKF and Ensemble-Based Sensitivity Analysis

引用

MONTHLY WEATHER REVIEW 2016年第9期144卷 3133-3157页

作者： Yokota, Sho Seko, Hiromu Kunii, Masaru Yamauchi, Hiroshi Niino, Hiroshi Japan Meteorol Agcy Meteorol Res Inst Tsukuba Japan Japan Agcy Marine Earth Sci & Technol Yokohama Kanagawa Japan Japan Meteorol Agcy Observat Dept Tokyo Japan Univ Tokyo Atmosphere & Ocean Res Inst Kashiwa Chiba Japan

A tornadic supercell and associated low-level mesocyclone (LMC) observed on the Kanto Plain, Japan, on 6 May 2012 were predicted with a nonhydrostatic mesoscale model with a horizontal resolution of 350 m through assimilation of surface meteorological data (horizontal wind, temperature, and relative humidity) of high spatial density and C-band Doppler radar data (radial velocity and rainwater estimated from reflectivity and specific differential phase) with a local ensemble transform Kalman filter. With assimilation of both surface and radar data, a strong LMC was successfully predicted near the path of the actual tornado. When either surface or radar data were not assimilated, however, the LMC was not predicted. Therefore, both surface and radar data were essential for successful LMC forecasts. The factors controlling the strength of the predicted LMC, defined as a low-level maximum vertical vorticity, were clarified by an ensemble-based sensitivity analysis (ESA), which is a new approach for analyzing LMC intensification. The ESA showed that the strength of the LMC was sensitive to low-level convergence forward of the storm and to low-level relative humidity in the rear of the storm. Therefore, the correction of these low-level variables by assimilation of dense observations was found to be particularly important for forecasting and monitoring the LMC in the present case.

关键词： Atm/Ocean Structure/ Phenomena Tornadoes observational techniques and algorithms Radars/Radar observations Surface observations Mathematical and statistical techniques Kalman filters Forecasting Ensembles Models and modeling Data assimilation

来源：评论

学校读者我要写书评

暂无评论

On Averaging Aspect Ratios and Distortion Parameters over Ice Crystal Population Ensembles for Estimating Effective Scattering Asymmetry Parameters

引用

JOURNAL OF THE ATMOSPHERIC SCIENCES 2016年第2期73卷 775-787页

作者： van Diedenhoven, Bastiaan Ackerman, Andrew S. Fridlind, Ann M. Cairns, Brian Columbia Univ Ctr Climate Syst Res New York NY USA NASA Goddard Inst Space Studies New York NY 10025 USA

The use of ensemble-average values of aspect ratio and distortion parameter of hexagonal ice prisms for the estimation of ensemble-average scattering asymmetry parameters is evaluated. Using crystal aspect ratios greater than unity generally leads to ensemble-average values of aspect ratio that are inconsistent with the ensemble-average asymmetry parameters. When a definition of aspect ratio is used that limits the aspect ratio to below unity alpha(<= 1) for both hexagonal plates and columns, the effective asymmetry parameters calculated using ensemble-average aspect ratios are generally consistent with ensemble-average asymmetry parameters, especially if aspect ratios are geometrically averaged. Ensemble-average distortion parameters generally also yield effective asymmetry parameters that are largely consistent with ensemble-average asymmetry parameters. In the case of mixtures of plates and columns, it is recommended to geometrically average the alpha(<= 1) aspect ratios and to subsequently calculate the effective asymmetry parameter using a column or plate geometry when the contribution by columns to a given mixture's total projected area is greater or less than 50%, respectively. In addition, it is shown that ensemble-average aspect ratios, distortion parameters, and asymmetry parameters can generally be retrieved accurately from simulated multidirectional polarization measurements based on mixtures of varying columns and plates. However, such retrievals tend to be somewhat biased toward yielding columnlike aspect ratios. Furthermore, generally large retrieval errors can occur for mixtures with approximately equal contributions of columns and plates and for ensembles with strong contributions of thin plates.

关键词： Physical Meteorology and Climatology Cloud retrieval Ice crystals Optical properties observational techniques and algorithms Remote sensing

来源：评论

学校读者我要写书评

暂无评论

Lagrangian Surface Wave Motion and Stokes Drift Fluctuations

引用

JOURNAL OF PHYSICAL OCEANOGRAPHY 2016年第4期46卷 1009-1021页

作者： Herbers, T. H. C. Janssen, T. T. NorthWest Res Associates POB 1533 El Granada CA 94018 USA

Nonlinear effects in Lagrangian sea surface motions are important to understanding variability in wave-induced mass transport, wave-driven diffusion processes, and the interpretation of measurements obtained with moored or free-drifting buoys. This study evaluates the Lagrangian vertical and horizontal motions of a particle at the surface in a natural, random sea state using second-order, finite-depth wave theory. In deep water, the predicted low-frequency (infragravity) surface height fluctuations are much larger than Eulerian bound wave motions and of the opposite sign. Comparison to surface elevation bispectra observed with a moored buoy in steady, high-wind conditions shows good agreement and confirms that—in contrast to the Eulerian sea surface motion with predominant phase coupling between the spectral peak and double-frequency harmonic components—nonlinearity in Lagrangian wave observations is dominated by phase-coupled infragravity motions. Sea surface skewness estimates obtained from moored buoys in deep and shallow sites, over a wide range of wind–sea and swell conditions, are in good agreement with second-order theory predictions. Theory and field data analysis of surface drift motions in deep water reveal energetic [O(10) cm s^?1] infragravity velocity fluctuations that are several orders of magnitude larger and 180° out of phase with Eulerian infragravity motions. These large fluctuations in Stokes drift may be important in upper-ocean diffusion processes.

关键词： Circulation/ Dynamics Gravity waves Nonlinear dynamics Waves oceanic observational techniques and algorithms Surface observations

来源：评论

学校读者我要写书评

暂无评论

Further Exploring and Quantifying Uncertainties for Extended Reconstructed Sea Surface Temperature (ERSST) Version 4 (v4)

引用

JOURNAL OF CLIMATE 2016年第9期29卷 3119-3142页

作者： Huang, Boyin Thorne, Peter W. Smith, Thomas M. Liu, Wei Lawrimore, Jay Banzon, Viva F. Zhang, Huai-Min Peterson, Thomas C. Menne, Matthew Natl Ctr Environm Informat Asheville NC USA Maynooth Univ Dept Geog Maynooth Kildare Ireland Univ Maryland NOAA STAR SCSB College Pk MD 20742 USA Univ Maryland CICS ESSIC College Pk MD 20742 USA Univ Calif San Diego Scripps Inst Oceanog La Jolla CA 92093 USA

The uncertainty in Extended Reconstructed SST (ERSST) version 4 (v4) is reassessed based upon 1) reconstruction uncertainties and 2) an extended exploration of parametric uncertainties. The reconstruction uncertainty (U-r) results from using a truncated (130) set of empirical orthogonal teleconnection functions (EOTs), which yields an inevitable loss of information content, primarily at a local level. The U-r is assessed based upon 32 ensemble ERSST. v4 analyses with the spatially complete monthly Optimum Interpolation SST product. The parametric uncertainty (U-p) results from using different parameter values in quality control, bias adjustments, and EOT definition etc. The U-p is assessed using a 1000-member ensemble ERSST. v4 analysis with different combinations of plausible settings of 24 identified internal parameter values. At the scale of an individual grid box, the SST uncertainty varies between 0.3 degrees and 0.7 degrees C and arises from both U-r and U-p. On the global scale, the SST uncertainty is substantially smaller (0.03 degrees-0.14 degrees C) and predominantly arises from U-p. The SST uncertainties are greatest in periods and locales of data sparseness in the nineteenth century and relatively small after the 1950s. The global uncertainty estimates in ERSST. v4 are broadly consistent with independent estimates arising from the Hadley Centre SST dataset version 3 (HadSST3) and Centennial Observation-Based Estimates of SST version 2 (COBE-SST2). The uncertainty in the internal parameter values in quality control and bias adjustments can impact the SST trends in both the long-term (1901-2014) and "hiatus" (2000-14) periods.

关键词： Atm/Ocean Structure/ Phenomena Sea surface temperature observational techniques and algorithms Data processing In situ oceanic observations Sampling Mathematical and statistical techniques Error analysis Models and modeling Ensembles

来源：评论

学校读者我要写书评

暂无评论

A CloudSat Perspective on the Cloud Climatology and Its Association with Aerosol Perturbations in the Vertical over Eastern China

引用

JOURNAL OF THE ATMOSPHERIC SCIENCES 2016年第9期73卷 3599-3616页

作者： Chen, Tianmeng Guo, Jianping Li, Zhanqing Zhao, Chuanfeng Liu, Huan Cribb, Maureen Wang, Fu He, Jing Beijing Normal Univ State Key Lab Earth Surface Proc & Resource Ecol Beijing Peoples R China Beijing Normal Univ Coll Global Change & Earth Syst Sci Beijing Peoples R China Chinese Acad Meteorol Sci State Key Lab Severe Weather 46 Zhong Guan Cun South Ave Beijing 100081 Peoples R China Univ Maryland Dept Atmospher & Ocean Sci College Pk MD 20742 USA Univ Maryland Earth Syst Sci Interdisciplinary Ctr College Pk MD 20742 USA China Meteorol Adm Natl Satellite Meteorol Ctr Beijing Peoples R China

Many efforts have been taken to investigate aerosol cloud interactions from space, but only a few studies have examined the response of vertical cloud structure to aerosol perturbations. Three-dimensional cloud climatologies of eight different cloud types identified from the CloudSat level-2 cloud product during the warm season (May September) in 2008-10 over eastern China were first generated and analyzed. Using visibility as a proxy for cloud condensation nuclei, in combination with satellite-observed radar reflectivity, normalized contoured frequency by altitude diagrams of the differences in cloud radar reflectivity Z profiles under polluted and clean conditions were constructed. For shallow cumulus clouds (shallow Cu) Z tends to be inhibited, and it is enhanced in the upper layers for deep cumulus (deep Cu), nimbostratus (Ns), and deep convective clouds (DCC) under polluted conditions. Overall, analyses of the modified center of gravity (MCOG) and cloud-top height (CTH) also point to a similar aerosol effect, except for the nonsignificant changes in MCOGs and CTHs in deep Cu. The impacts of environmental factors such as lower-tropospheric stability and vertical velocity are also discussed for these types of clouds. Although consistent aerosol-induced elevations in MCOGs and CTHs for Ns and DCC clouds are observed, the effect of meteorology cannot be completely ruled out, which merits further analysis.

关键词： Atm/Ocean Structure/ Phenomena Clouds observational techniques and algorithms Radars/Radar observations Applications Air pollution Cloud seeding

来源：评论

学校读者我要写书评

暂无评论

Quasi-Vertical Profiles-A New Way to Look at Polarimetric Radar Data

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第3期33卷 551-562页

作者： Ryzhkov, Alexander Zhang, Pengfei Reeves, Heather Kumjian, Matthew Tschallener, Timo Troemel, Silke Simmer, Clemens Univ Oklahoma Cooperat Inst Mesoscale Meteorol Studies Norman OK 73072 USA NOAA Natl Severe Storms Lab OAR Norman OK 73069 USA Penn State Univ University Pk PA 16802 USA Univ Bonn Inst Meteorol Bonn Germany

A novel methodology is introduced for processing and presenting polarimetric data collected by weather surveillance radars. It involves azimuthal averaging of radar reflectivity Z, differential reflectivity Z(DR), cross-correlation coefficient rho(hv), and differential phase phi(DP) at high antenna elevation, and presenting resulting quasi-vertical profiles (QVPs) in a height-versus-time format. Multiple examples of QVPs retrieved from the data collected by S-, C-, and X-band dual-polarization radars at elevations ranging from 6.4 degrees to 28 degrees illustrate advantages of the QVP technique. The benefits include an ability to examine the temporal evolution of microphysical processes governing precipitation production and to compare polarimetric data obtained from the scanning surveillance weather radars with observations made by vertically looking remote sensors, such as wind profilers, lidars, radiometers, cloud radars, and radars operating on spaceborne and airborne platforms. Continuous monitoring of the melting layer and the layer of dendritic growth with high vertical resolution, and the possible opportunity to discriminate between the processes of snow aggregation and riming, constitute other potential benefits of the suggested methodology.

关键词： observational techniques and algorithms Radars/Radar observations Remote sensing

来源：评论

学校读者我要写书评

暂无评论

Determination of Convective Boundary Layer Entrainment Fluxes, Dissipation Rates, and the Molecular Destruction of Variances: Theoretical Description and a Strategy for Its Confirmation with a Novel Lidar System Synergy

引用

JOURNAL OF THE ATMOSPHERIC SCIENCES 2016年第2期73卷 667-692页

作者： Wulfmeyer, Volker Muppa, Shravan Kumar Behrendt, Andreas Hammann, Eva Spaeth, Florian Sorbjan, Zbigniew Turner, David D. Hardesty, R. Michael Univ Hohenheim Inst Phys & Meteorol Garbenstr 30 D-70599 Stuttgart Germany Univ Colorado NOAA Cooperat Inst Res Environm Sci Boulder CO 80309 USA Marquette Univ Dept Phys Milwaukee WI 53233 USA NOAA Natl Severe Storms Lab Norman OK 73069 USA NOAA Earth Syst Res Lab Boulder CO USA

Atmospheric variables in the convective boundary layer (CBL), which are critical for turbulence parameterizations inweather and climatemodels, are assessed. These include entrainment fluxes, higher-ordermoments of humidity, potential temperature, and vertical wind, as well as dissipation rates. Theoretical relationships between the integral scales, gradients, and higher-order moments of atmospheric variables, fluxes, and dissipation rates are developed mainly focusing on the entrainment layer (EL) at the top of the CBL. These equations form the starting point for tests of and new approaches in CBL turbulence parameterizations. For the investigation of these relationships, an observational approach using a synergy of ground-based water vapor, temperature, and wind lidar systems is proposed. These systems measure instantaneous vertical profiles with high temporal and spatial resolution throughout the CBL including the EL. The resolution of these systems permits the simultaneous measurement of gradients and fluctuations of these atmospheric variables. For accurate analyses of the gradients and the shapes of turbulence profiles, the lidar system performances are very important. It is shown that each lidar profile can be characterized very well with respect to bias and system noise and that the constant bias has negligible effect on the measurement of turbulent fluctuations. It is demonstrated how different gradient relationships can be measured and tested with the proposed lidar synergy within operational measurements or new field campaigns. Particularly, a novel approach is introduced for measuring the rate of destruction of humidity and temperature variances, which is an important component of the variance budget equations.

关键词： Circulation/ Dynamics Entrainment Fluxes Turbulence Atm/Ocean Structure/ Phenomena Boundary layer observational techniques and algorithms Lidars/Lidar observations

来源：评论

学校读者我要写书评

暂无评论

Heat, Salt, and Freshwater Budgets for a Glacial Fjord in Greenland

引用

JOURNAL OF PHYSICAL OCEANOGRAPHY 2016年第9期46卷 2735-2768页

作者： Jackson, Rebecca H. Straneo, Fiammetta Woods Hole Oceanog Inst Woods Hole MA 02543 USA

In Greenland's glacial fjords, heat and freshwater are exchanged between glaciers and the ocean. Submarine melting of glaciers has been implicated as a potential trigger for recent glacier acceleration, and observations of ocean heat transport are increasingly being used to infer the submarine melt rates. The complete heat, salt, and mass budgets that underlie such methods, however, have been largely neglected. Here, a new framework for exploring glacial fjord budgets is developed. Building on estuarine studies of salt budgets, the heat, salt, and mass transports through the fjord are decomposed, and new equations for calculating freshwater fluxes from submarine meltwater and runoff are presented. This method is applied to moored records from Sermilik Fjord, near the terminus of Helheim Glacier, to evaluate the dominant balances in the fjord budgets and to estimate freshwater fluxes. Throughout the year, two different regimes are found. In the nonsummer months, advective transports are balanced by changes in heat/salt storage within their ability to measure;freshwater fluxes cannot be inferred as a residual. In the summer, a mean exchange flow emerges, consisting of inflowing Atlantic water and outflowing glacially modified water. This exchange transports heat toward the glacier and is primarily balanced by changes in storage and latent heat for melting ice. The total freshwater flux increases over the summer, reaching 1200 +/- 700 m(3) s(-1) of runoff and 1500 +/- 500 m(3) s(-1) of submarine meltwater from glaciers and icebergs in August. The methods and results highlight important components of fjord budgets, particularly the storage and barotropic terms, that have been not been appropriately considered in previous estimates of submarine melting.

关键词： Geographic location/entity Estuaries Glaciers Circulation/ Dynamics Coastal flows Atm/Ocean Structure/ Phenomena Freshwater Snowmelt/icemelt observational techniques and algorithms In situ oceanic observations

来源：评论

学校读者我要写书评

暂无评论

Combining In Situ and Satellite Observations to Retrieve Salinity and Density at the Ocean Surface

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第6期33卷 1211-1223页

作者： Droghei, R. Nardelli, B. Buongiorno Santoleri, R. CNR Ist Sci Atmosfera & Clima Via Fosso Cavaliere 100 I-00133 Rome Italy CNR Ist Ambiente Marino Costiero I-80125 Naples Italy

Monitoring sea surface density (SSD), sea surface salinity (SSS), and sea surface temperature (SST) allows for investigating important aspects of the earth system dynamics, with relevant implications on both local/ regional short-scale processes and global climate. Different approaches combine in situ measurements and satellite data to provide gap-free SSS at regular spatial and temporal resolution, aiming to resolve ocean mesoscale. Depending on the application, however, knowing SSD would be more useful than SSS and/or SST alone. Indeed, even if density can be obtained by combining SSS and SST maps at the same nominal resolution, this procedure can lead to spurious features and larger errors when SSS and SST are obtained from different observations and interpolation techniques, especially at the mesoscale. A multidimensional covariance model is applied to interpolate either in situ salinity or in situ density measurements and to build dynamically coherent surface fields, using satellite SST differences as an additional parameter in the optimal estimate. SSS/SSD level 4 (L4) maps are reconstructed over the North Atlantic area, analyzing one month of data. The L4 data are validated using data from the first Salinity Processes in the Upper Ocean Regional Study (SPURS-1) field campaign. The root-mean-square error (RMSE) ranges between 0.03 and 0.13 for the SSS L4 data, and between 0.09 and 0.32 kg m(-3) for the SSD L4 data, with improvements of up to 20% with respect to standard products. Aholdout validation provides similar values for the SSS RMSE (0.13 divided by 0.17) and the SSD RMSE (0.13 divided by 0.17 kg m(-3)). The limitations and advantages of the two approaches are further discussed and analyzed by looking at spatial wavenumber spectra, showing that the multidimensional optimum interpolation (OI) method significantly increases the L4 effective resolution.

关键词： Geographic location/entity Atlantic Ocean Circulation/ Dynamics Mesoscale processes Physical Meteorology and Climatology Salinity Surface temperature observational techniques and algorithms In situ oceanic observations Remote sensing

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：