检索结果-内蒙古大学图书馆

Research Aircraft Determination of D-Value Cross Sections

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第2期33卷 391-396页

作者： Parish, Thomas R. Rahn, David A. Leon, Dave Univ Wyoming Dept Atmospher Sci Dept 30381000 E Univ Ave Laramie WY 82071 USA Univ Kansas Dept Geog & Atmospher Sci Lawrence KS 66045 USA

Use of an airborne platform to determine the dynamics of atmospheric motion has been ongoing for over three decades. Much of the effort has been centered on the determination of the horizontal pressure gradient force along an isobaric surface, and with wind measurements the nongeostrophic components of motion can be obtained. Recent advances using differential GPS-based altitude measurements allow accurate assessment of the geostrophic wind. Porpoise or sawtooth maneuvers are used to determine the vertical cross section of the horizontal pressure gradient force. D-values, the difference of the height of a given pressure level from that in a reference atmosphere, are used to isolate the vertical structure of the horizontal component of the pressure gradient force from the vastly larger hydrostatic pressure gradient. Comparison of measured D-value cross sections with airborne measurements of the horizontal pressure gradient is shown. Comparison of D-values with output from the WRF Model demonstrates that the airborne measurements are consistent with finescale numerical simulations. This technique provides a means of inferring the thermal wind, thereby enabling a detailed examination of the vertical structure of the forcing of mesoscale and synoptic-scale wind regimes.

关键词： observational techniques and algorithms Dynamics Aircraft observations Circulation/ Dynamics In situ atmospheric observations

来源：评论

学校读者我要写书评

暂无评论

An Improved Liquid Water Absorption Model at Microwave Frequencies for Supercooled Liquid Water Clouds

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第1期33卷 33-44页

作者： Turner, D. D. Kneifel, S. Cadeddu, M. P. NOAA Natl Severe Storms Lab 120 David L Boren Blvd Norman OK 73072 USA McGill Univ Dept Atmospher & Ocean Sci Montreal PQ Canada Argonne Natl Lab Lemont IL USA

An improved liquid water absorption model is developed for frequencies between 0.5 and 500 GHz. The empirical coefficients for this model were retrieved from a dataset that consists of both laboratory observations of the permittivity of liquid water (primarily at temperatures above 0 degrees C) and field observations collected by microwave radiometers in three separate locations with observations at temperatures as low as -32 degrees C. An optimal estimation framework is used to retrieve the model's coefficients. This framework shows that there is high information content in the observations for seven of the nine model coefficients, but that the uncertainties in all of the coefficients result in less than 15% uncertainty in the liquid water absorption coefficient for all temperatures between -32 degrees and 0 degrees C and frequencies between 23 and 225 GHz. Furthermore, this model is more consistent with both the laboratory and field observations over all frequencies and temperatures than other popular absorption models.

关键词： observational techniques and algorithms Cloud retrieval Microwave observations Remote sensing

来源：评论

学校读者我要写书评

暂无评论

Sea Surface Height Variability in Drake Passage

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第4期33卷 669-683页

作者： Donohue, Kathleen A. Kennelly, Maureen A. Cutting, Amy Univ Rhode Isl Grad Sch Oceanog 215 South Ferry Rd Narragansett RI 02882 USA Naval Undersea Warfare Ctr Newport RI USA

Intercomparisons between altimeter sea surface height (SSH) and open-ocean in situ observations have been limited owing to sparse available datasets. Here, SSH anomaly (SSHA) determined from current and pressure recording inverted echo sounders (CPIES) from the cDrake experiment were compared with an up-to-date AVISO-mapped product. Meandering Antarctic Circumpolar Current (ACC) fronts in the passage interior elevated SSHA variance;south of the Shackleton Fracture Zone and along the northern continental slope, the variance decreased by factors between 6 and 10. In situ analysis focused on the two constituents of SSHA, SSHA(ref) determined from bottom pressure and SSHA(bcb), calculated from geopotential height referenced to the bottom. The peak variance of both SSHA(bcb) and SSHA(ref) occurred in the energetic region between the Subantarctic Front and the Polar Front. The contribution of SSHA(bcb), to total SSHA variance was greater than 40% at all sites and averaged over all sites it was 73%. For most sites, high-frequency (>1/20 cpd) SSHA(bcb) signals dominated total high-frequency variance. Aliasing of high-frequency signals resulting from 10-day altimeter sampling was assessed. The fraction of aliased energy at frequencies longer than 1/50 cpd for sites at and north of the Shackleton Fracture Zone approached 0.25 and approached 0.50 for southern sites. CPIES and mapped altimeter SSHA agreed well. The mean correlation coefficient was 0.82 and the mean RMS difference was 0.075 m. Correlations between CPIES and AVISO were notably poorer at the northern and southern boundaries. RMS differences increased as a function of CPIES high-frequency SSHA variance because the mapped altimetry product does not resolve these frequencies.

关键词： Altimetry Anomalies In situ oceanic observations observational techniques and algorithms Oceanic variability Satellite observations Variability

来源：评论

学校读者我要写书评

暂无评论

Analysis of Cumulus Cloud Updrafts as Observed with 1-Min Resolution Super Rapid Scan GOES Imagery

引用

MONTHLY WEATHER REVIEW 2016年第2期144卷 811-830页

作者： Mecikalski, John R. Jewett, Christopher P. Apke, Jason M. Carey, Larry D. Univ Alabama Dept Atmospher Sci Huntsville AL 35899 USA Univ Alabama Ctr Earth Syst Sci Huntsville AL 35899 USA

A study was undertaken to examine growing cumulus clouds using 1-min time resolution Super Rapid Scan Operations for Geostationary Operational Environmental Satellite-R (GOES-R) (SRSOR) imagery to diagnose in-cloud processes from cloud-top information. SRSOR data were collected using GOES-14 for events in 2012-14. Use of 1-min resolution SRSOR observations of rapidly changing scenes provides far more insights into cloud processes as compared to when present-day 5-15-min time resolution GOES data are used. For midday times on five days, cloud-top temperatures were cataloged for 71 cumulus clouds as they grew to possess anvils and often overshooting cloud tops, which occurred over 33-152-min time periods. Characteristics of the SRSOR-observed updrafts were examined individually, on a per day basis, and collectively, to reveal unique aspects of updraft behavior, strength, and acceleration as related to the ambient stability profile and cloud-top glaciation. A conclusion is that the 1-min observations capture two specific cumulus cloud growth periods, less rapid cloud growth between the level of free convection and the 0 degrees C isotherm level, followed by more rapid growth shortly after the time of cloud-top glaciation. High correlation is found between estimated vertical motion (w) and the amount of convective available potential energy (CAPE) realized to the cloud-top level as clouds grew, which suggests that updrafts were responding to the local buoyancy quite strongly. Influences of the environmental buoyancy profile shape and evidence of entrainment on cloud growth are also found through these SRSOR data analyses.

关键词： Physical Meteorology and Climatology Buoyancy Convective-scale processes Cumulus clouds observational techniques and algorithms Cloud tracking cloud motion winds Kinematics Satellite observations

来源：评论

学校读者我要写书评

暂无评论

Investigating the Eddy Diffusivity Concept in the Coastal Ocean

引用

JOURNAL OF PHYSICAL OCEANOGRAPHY 2016年第7期46卷 2201-2218页

作者： Rypina, I. I. Kirincich, A. Lentz, S. Sundermeyer, M. Woods Hole Oceanog Inst Woods Hole MA 02543 USA Univ Massachusetts Dartmouth New Bedford MA USA

This paper aims to test the validity, utility, and limitations of the lateral eddy diffusivity concept in a coastal environment through analyzing data from coupled drifter and dye releases within the footprint of a high-resolution (800 m) high-frequency radar south of Martha's Vineyard, Massachusetts. Specifically, this study investigates how well a combination of radar-based velocities and drifter-derived diffusivities can reproduce observed dye spreading over an 8-h time interval. Adrifter-based estimate of an anisotropic diffusivity tensor is used to parameterize small-scale motions that are unresolved and underresolved by the radar system. This leads to a significant improvement in the ability of the radar to reproduce the observed dye spreading.

关键词： Circulation/ Dynamics Coastal flows Diffusion Lagrangian circulation/transport observational techniques and algorithms Radars/Radar observations Models and modeling Tracers

来源：评论

学校读者我要写书评

暂无评论

Creation and Validation of a Comprehensive 1° by 1° Daily Gridded North American Dataset for 1900-2009: Snowfall

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第5期33卷 857-871页

作者： Kluver, Daria Mote, Tom Leathers, Daniel Henderson, Gina R. Chan, Weihan Robinson, David A. Cent Michigan Univ Mt Pleasant MI 48859 USA Univ Georgia Athens GA 30602 USA Univ Delaware Newark DE USA US Naval Acad Annapolis MD 21402 USA Rutgers State Univ New Brunswick NJ 08903 USA

This study details the creation of a gridded snowfall dataset for North America, with focus on the quality of the interpolated product. Daily snowfall amounts from National Weather Service Cooperative Observer Program stations and Meteorological Service of Canada surface stations are interpolated to 18 by 18 grids from 1900 to 2009 and examined for data record length and quality. The interpolation is validated spatially and temporally through the use of stratified sampling and k-fold cross-validation analyses. Interpolation errors average around 0.5 cm and range from less than 0.01 to greater than 2.5 cm. For most locations, this is within the measurement sensitivity. Grid cells with large variations in elevation experience higher errors and should be used with caution. A new gridded snowfall climatology is presented based on in situ observations that capture seasonal and interannual variability in monthly snowfall over most of the North American land area from 1949 to 2009. The Community Collaborative Rain, Hail and Snow Network is used as an independent set of point data that is compared to the gridded product. Errors are mainly in the form of the gridded data underestimating snowfall compared to the point data. The spatial extent, temporal length, and resolution of the dataset are unprecedented with regard to observational snowfall products and will present new opportunities for examining snowfall across North America.

关键词： Atm/Ocean Structure/ Phenomena Snowfall Physical Meteorology and Climatology Climatology observational techniques and algorithms Climate records Surface observations Mathematical and statistical techniques Interpolation schemes

来源：评论

学校读者我要写书评

暂无评论

Statistics of Nonlinear Internal Waves during the Shallow Water 2006 Experiment

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第4期33卷 839-846页

作者： Badiey, Mohsen Wan, Lin Lynch, James F. Univ Delaware Coll Earth Ocean & Environm Newark DE 19716 USA Woods Hole Oceanog Inst Appl Ocean Phys & Engn Woods Hole MA 02543 USA

During the Shallow Water Acoustic Experiment 2006 (SW06) conducted on the New Jersey continental shelf in the summer of 2006, detailed measurements of the ocean environment were made along a fixed reference track that was parallel to the continental shelf. The time-varying environment induced by nonlinear internal waves (NLIWs) was recorded by an array of moored thermistor chains and by X-band radars from the attending research vessels. Using a mapping technique, the three-dimensional (3D) temperature field for over a month of NLIW events is reconstructed and analyzed to provide a statistical summary of important NLIW parameters, such as the NLIW propagation speed, direction, and amplitude. The results in this paper can be used as a database for studying the NLIW generation, propagation, and fidelity of nonlinear internal wave models.

关键词： Continental shelf/slope Data processing Geographic location/entity In situ oceanic observations Mathematical and statistical techniques North America observational techniques and algorithms Sampling Statistics

来源：评论

学校读者我要写书评

暂无评论

Stratospheric Temperature Trends over 1979-2015 Derived from Combined SSU, MLS, and SABER Satellite Observations

引用

JOURNAL OF CLIMATE 2016年第13期29卷 4843-4859页

作者： Randel, William J. Smith, Anne K. Wu, Fei Zou, Cheng-Zhi Qian, Haifeng Natl Ctr Atmospher Res 3450 Mitchell Lane Boulder CO 80301 USA NOAA Ctr Satellite Applicat & Res NESDIS College Pk MD USA Earth Resource Technol Inc Laurel MD USA

Temperature trends in the middle and upper stratosphere are evaluated using measurements from the Stratospheric Sounding Unit (SSU), combined with data from the Aura Microwave Limb Sounder (MLS) and Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) instruments. Data from MLS and SABER are vertically integrated to approximate the SSU weighting functions and combined with SSU to provide a data record spanning 1979-2015. Vertical integrals are calculated using empirically derived Gaussian weighting functions, which provide improved agreement with high-latitude SSU measurements compared to previously derived weighting functions. These merged SSU data are used to evaluate decadal-scale trends, solar cycle variations, and volcanic effects from the lower to the upper stratosphere. Episodic warming is observed following the volcanic eruptions of El Chichon (1982) and Mt. Pinatubo (1991), focused in the tropics in the lower stratosphere and in high latitudes in the middle and upper stratosphere. Solar cycle variations are centered in the tropics, increasing in amplitude from the lower to the upper stratosphere. Linear trends over 1979-2015 show that cooling increases with altitude from the lower stratosphere (from similar to-0.1 to -0.2 K decade (1)) to the middle and upper stratosphere (from;similar to-0.5 to -0.6 K decade (1)). Cooling in the middle and upper stratosphere is relatively uniform in latitudes north of about 30 degrees S, but trends decrease to near zero over the Antarctic. Mid-and upper-stratospheric temperatures show larger cooling over the first half of the data record (1979-97) compared to the second half (1998-2015), reflecting differences in upper-stratospheric ozone trends between these periods.

关键词： Circulation/ Dynamics Stratospheric circulation observational techniques and algorithms Climate records Satellite observations Variability Decadal variability Trends

来源：评论

学校读者我要写书评

暂无评论

Comments on "Incorporating the Effects of Moisture into a Dynamical Parameter: Moist Vorticity and Moist Divergence"

引用

WEATHER AND FORECASTING 2016年第4期31卷 1393-1396页

作者： Schultz, David M. Spengler, Thomas Univ Manchester Ctr Atmospher Sci Sch Earth Atmospher & Environm Sci Simon BldgOxford Rd Manchester M13 9PL Lancs England Univ Bergen Inst Geophys Bergen Norway Bjerknes Ctr Climate Res Bergen Norway

In a recent article, Qian et al. introduced the quantities moist vorticity and moist divergence to diagnose locations of heavy rain. These quantities are constructed by multiplying the relative vorticity and divergence by relative humidity to the power k, where k = 10 in their article. Their approach is similar to that for the previously constructed quantity generalized moist potential vorticity. This comment critiques the approach of Qian et al., demonstrating that the moist vorticity, moist divergence, and by extension generalized moist potential vorticity are flawed mathematically and meteorologically. Raising relative humidity to the 10th power is poorly justified and is based on a single case study at a single time. No meteorological evidence is presented for why areas of moist vorticity and moist divergence should overlap with regions of 24-h accumulated rainfall. All three quantities have not been verified against the output of precipitation directly from the model nor is the approach of combining meteorological quantities into a single parameter appropriate in an ingredients-based forecasting approach. Researchers and forecasters are advised to plot the model precipitation directly and employ an ingredients-based approach, rather than rely on these flawed quantities.

关键词： Circulation/ Dynamics Convection Atm/Ocean Structure/ Phenomena Rainfall observational techniques and algorithms Kinematics Forecasting Forecasting Forecasting techniques Operational forecasting

来源：评论

学校读者我要写书评

暂无评论

observational Evidence of Frontal-Scale Atmospheric Responses to Kuroshio Extension Variability

引用

JOURNAL OF CLIMATE 2015年第23期28卷 9459-9472页

作者： Wang, Yi-Hui Liu, W. Timothy CALTECH Jet Prop Lab Pasadena CA 91109 USA

This study investigates the regional atmospheric response to the Kuroshio Extension (KE) using a combination of multiple satellite observations and reanalysis data from boreal winter over a period of at least a decade. The goal is to understand the relationship between KE variations and atmospheric responses at low frequencies. A climate index is used to measure the interannual to decadal KE variability, which leaves remarkable imprints on the mesoscale sea surface temperature (SST). Clear spatial coherence between the SST signals and frontal-scale atmospheric variables, including surface wind convergence, vertical velocity, precipitation, and clouds, is identified by linear regression analysis. Consistent with previous studies, the penetrating effect of the KE variability on the free atmosphere is found. The westward tilt of the atmospheric response above the KE near 500 hPa is revealed. The difference in the associations of frontal-scale air temperature and geopotential height with the KE variability between the satellite observations and the reanalysis data suggests an imperfect interpretation of frontal-scale oceanic forcing on the overlying atmosphere in the reanalysis assimilation system.

关键词： Circulation Dynamics Atmosphere-ocean interaction Boundary currents Atm Ocean Structure Phenomena Marine boundary layer Troposphere observational techniques and algorithms Satellite observations

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：