检索结果-内蒙古大学图书馆

Assimilation of Synthetic GOES-R ABI Infrared Brightness Temperatures and WSR-88D Radar Observations in a High-Resolution OSSE

引用

MONTHLY WEATHER REVIEW 2016年第9期144卷 3159-3180页

作者： Cintineo, Rebecca M. Otkin, Jason A. Jones, Thomas A. Koch, Steven Stensrud, David J. Univ Wisconsin Madison Cooperat Inst Meteorol Satellite Studies Madison WI USA Univ Oklahoma Cooperat Inst Mesoscale Meteorol Studies Norman OK 73019 USA NOAA OAR Natl Severe Storms Lab Norman OK USA Penn State Univ Dept Meteorol 503 Walker Bldg University Pk PA 16802 USA

This study uses an observing system simulation experiment to explore the impact of assimilating GOES-R Advanced Baseline Imager (ABI) 6.95-mu m brightness temperatures and Weather Surveillance Radar-1988 Doppler (WSR-88D) reflectivity and radial velocity observations in an ensemble data assimilation system. A high-resolution truth simulation was used to create synthetic radar and satellite observations of a severe weather event that occurred across the U.S. central plains on 4-5 June 2005. The experiment employs the Weather Research and Forecasting Model at 4-km horizontal grid spacing and the ensemble adjustment Kalman filter algorithm in the Data Assimilation Research Testbed system. The ability of GOES-R ABI brightness temperatures to improve the analysis and forecast accuracy when assimilated separately or simultaneously with Doppler radar reflectivity and radial velocity observations was assessed, along with the use of bias correction and different covariance localization radii for the brightness temperatures. Results show that the radar observations accurately capture the structure of a portion of the storm complex by the end of the assimilation period, but that more of the storms and atmospheric features are reproduced and the accuracy of the ensuing forecast improved when the brightness temperatures are also assimilated.

关键词： observational techniques and algorithms Radars/Radar observations Satellite observations Sensitivity studies Forecasting Short-range prediction Models and modeling Data assimilation Numerical weather prediction/forecasting

来源：评论

学校读者我要写书评

暂无评论

Fetch- and Duration-Limited Nature of Surface Wave Growth inside Tropical Cyclones: With Applications to Air-Sea Exchange and Remote Sensing

引用

JOURNAL OF PHYSICAL OCEANOGRAPHY 2016年第1期46卷 41-56页

作者： Hwang, Paul A. Naval Res Lab Remote Sensing Div 4555 Overlook Ave SW Washington DC 20375 USA

The 2D wavenumber spectra collected by an airborne scanning radar altimeter in hurricane hunter missions are used to investigate the fetch- and duration-limited nature of wave growth inside hurricanes. Despite the much more complex wind-forcing conditions, the dimensionless growth curves obtained with the wind-wave triplets (reference wind velocity, significant wave height, and dominant wave period) inside hurricanes, except near the eye region, are comparable to the reference similarity counterparts constructed with the wind-wave triplets collected in field experiments conducted under ideal quasi-steady fetch-limited conditions. In dimensionless terms, the youngest waves are in the back quarter of the hurricane. In the Northern Hemisphere, the dimensionless frequency decreases systematically counterclockwise (CCW), and the most mature waves are in the left-hand sector. Except for those waves near the eye region, the dominant wave phase speeds are about 0.32 to 0.71 times of the local wind speed, and they are proper wind seas. Based on the computation of the wind input or energy dissipation in the wave field, a conservative estimate of the air-sea energy exchange over the coverage area of a category one hurricane is about 5 TW. Formulas for the effective fetches and durations in the three hurricane sectors are derived from the data. Using these formulas together with the wave growth functions, the full set of wind-wave triplets can be calculated knowing only one of the three. These results may enhance the capability and scope of monitoring hurricanes from space.

关键词： Circulation Dynamics Hurricanes Waves oceanic Wind waves observational techniques and algorithms Remote sensing Satellite observations

来源：评论

学校读者我要写书评

暂无评论

Estimating Nonraining Surface Parameters to Assist GPM Constellation Radiometer Precipitation algorithms

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第7期33卷 1333-1353页

作者： Turk, F. Joseph Haddad, Z. S. You, Y. CALTECH Jet Prop Lab 4800 Oak Grove DrMail Stop 300-243 Pasadena CA 91109 USA Univ Maryland Earth Syst Sci Interdisciplinary Ctr College Pk MD 20742 USA

The joint National Aeronautics and Space Administration (NASA) and Japanese Aerospace Exploration Agency (JAXA) Global Precipitation Measurement (GPM) is a constellation mission, centered upon observations from the core satellite dual-frequency precipitation radar (DPR) and its companion passive microwave (MW) GPM Microwave Imager (GMI). One of the key challenges for GPM is how to link the information from the single DPR across all passive MW sensors in the constellation, to produce a globally consistent precipitation product. Commonly, the associated surface emissivity and environmental conditions at the satellite observation time are interpolated from ancillary data, such as global forecast models and emissivity climatology, and are used for radiative transfer simulations and cataloging/indexing the brightness temperature (TB) observations and simulations within a common MW precipitation retrieval framework. In this manuscript, the feasibility of an update to the surface emissivity state at or near the satellite observation time, regardless of surface type, is examined for purposes of assisting these algorithms with specification of the surface and environmental conditions. Since the constellation MW radiometers routinely observe many more nonprecipitating conditions than precipitating conditions, a principal component analysis is developed from the noncloud GMI-DPR observations as a means to characterize the emissivity state vector and to consistently track the surface and environmental conditions. The method is demonstrated and applied over known complex surface conditions to probabilistically separate cloud and cloud-free scenes. The ability of the method to globally identify "self-similar'' surface locations from the TB observations without requiring any ancillary knowledge of geographical location or time is demonstrated.

关键词： Atm/Ocean Structure/ Phenomena Complex terrain Geographic location/entity Microwave observations observational techniques and algorithms Physical Meteorology and Climatology Radars/Radar observations Rainfall Satellite observations Storm environments

来源：评论

学校读者我要写书评

暂无评论

Hurricane Irene Sensitivity to Stratified Coastal Ocean Cooling

引用

MONTHLY WEATHER REVIEW 2016年第9期144卷 3507-3530页

作者： Seroka, Greg Miles, Travis Xu, Yi Kohut, Josh Schofield, Oscar Glenn, Scott Rutgers State Univ Sch Environm & Biol Sci Dept Marine & Coastal Sci Ctr Ocean Observing Leadership New Brunswick NJ 08901 USA East China Normal Univ State Key Lab Estuarine & Coastal Res Shanghai Peoples R China

Cold wakes left behind by tropical cyclones (TCs) have been documented since the 1940s. Many questions remain, however, regarding the details of the processes creating these cold wakes and their in-storm feedbacks onto tropical cyclone intensity. This largely reflects a paucity of measurements within the ocean, especially during storms. Moreover, the bulk of TC research efforts have investigated deep ocean processes where tropical cyclones spend the vast majority of their lifetimes and very little attention has been paid to coastal ocean processes despite their critical importance to shoreline populations. Using Hurricane Irene (2011) as a case study, the impact of the cooling of a stratified coastal ocean on storm intensity, size, and structure is quantified. Significant ahead-of-eye-center cooling (at least 6 degrees C) of the Mid-Atlantic Bight occurred as a result of coastal baroclinic processes, and operational satellite SST products and existing coupled ocean atmosphere hurricane models did not capture this cooling. Irene's sensitivity to the cooling is tested, and its intensity is found to be most sensitive to the cooling over all other tested WRF parameters. Further, including the cooling in atmospheric modeling mitigated the high storm intensity bias in predictions. Finally, it is shown that this cooling not track, wind shear, or dry air intrusion was the key missing contribution in modeling Irene's rapid decay prior to New Jersey landfall. Rapid and significant intensity changes just before landfall can have substantial implications on storm impacts wind damage, storm surge, and inland flooding and thus, coastal ocean processes must be resolved in future hurricane models.

关键词： Geographic location/entity Continental shelf/slope Atm/Ocean Structure/ Phenomena Hurricanes/typhoons Physical Meteorology and Climatology Atmosphere-ocean interaction observational techniques and algorithms Satellite observations Sensitivity studies Forecasting Numerical weather prediction/forecasting

来源：评论

学校读者我要写书评

暂无评论

Fulfilling Observing System Implementation Requirements with the Global Drifter Array

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第4期33卷 685-695页

作者： Lumpkin, Rick Centurioni, Luca Perez, Renellys C. NOAA Atlantic Oceanog & Meteorol Lab Miami FL 33149 USA Univ Calif San Diego Scripps Inst Oceanog La Jolla CA 92093 USA Univ Miami Cooperat Inst Marine & Atmospher Studies Miami FL USA

The Global Ocean Observing System (GOOS) requirements for in situ surface temperature and velocity measurements call for observations at 5 degrees x 5 degrees resolution. A key component of the GOOS that measures these essential climate variables is the global array of surface drifters. In this study, statistical observing system sampling experiments are performed to evaluate how many drifters are required to achieve the GOOS requirements, both with and without the presence of a completed global tropical moored buoy array at 5 degrees S-5 degrees N. The statistics for these simulations are derived from the evolution of the actual global drifter array. It is concluded that drifters should be deployed within the near-equatorial band even though that band is also in principle covered by the tropical moored array, as the benefits of not doing so are marginal. It is also concluded that an optimal design half-life for the drifters is similar to 450 days, neglecting external sources of death, such as running aground or being picked up. Finally, it is concluded that comparing the drifter array size to the number of static 5 degrees x 5 degrees open-ocean bins is not an ideal performance indicator for system evaluation;a better performance indicator is the fraction of 5 degrees x 5 degrees open-ocean bins sampled, neglecting bins with high drifter death rates.

关键词： Buoy observations Circulation/ Dynamics Currents Forecasting In situ oceanic observations Lagrangian circulation/transport observational techniques and algorithms Statistical forecasting Surface observations

来源：评论

学校读者我要写书评

暂无评论

The Sensitivity of SeaWiFS Ocean Color Retrievals to Aerosol Amount and Type

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第6期33卷 1185-1209页

作者： Kahn, Ralph A. Sayer, Andrew M. Ahmad, Ziauddin Franz, Bryan A. NASA Div Earth Sci Goddard Space Flight Ctr Mail Code 613 Greenbelt MD 20771 USA Univ Space Res Assoc Goddard Earth Sci Technol & Res Columbia MD USA Sci & Data Syst Inc Silver Spring MD USA

As atmospheric reflectance dominates top-of-the-atmosphere radiance over ocean, atmospheric correction is a critical component of ocean color retrievals. This paper explores the operational Sea-viewing Wide Field-of-view Sensor (SeaWiFS) algorithm atmospheric correction with similar to 13 000 coincident surface-based aerosol measurements. Aerosol optical depth at 440 nm (AOD(440)) is overestimated for AOD below similar to 0.1-0.15 and is increasingly underestimated at higher AOD;also, single-scattering albedo (SSA) appears overestimated when the actual value

关键词： Atm/Ocean Structure/ Phenomena Oceanic mixed layer Physical Meteorology and Climatology Aerosols observational techniques and algorithms Remote sensing Satellite observations

来源：评论

学校读者我要写书评

暂无评论

A Validation of the Antarctic Mesoscale Prediction System Using Self-Organizing Maps and High-Density Observations from SNOWWEB

引用

MONTHLY WEATHER REVIEW 2016年第9期144卷 3181-3200页

作者： Jolly, Ben Mcdonald, Adrian J. Coggins, Jack H. J. Zawar-Reza, Peyman Cassano, John Lazzara, Matthew Graham, Geoffery Plank, Graeme Petterson, Orlon Dale, Ethan Univ Canterbury Christchurch New Zealand Univ Colorado Boulder Boulder CO USA Univ Wisconsin Madison Madison WI USA Madison Area Tech Coll Madison WI USA

This study compares high-resolution output (1.1-km horizontal grid length) from twice-daily forecasts produced by the Antarctic Mesoscale Prediction System (AMPS) with a dense observational network east of Ross Island. Covering 10 000 km(2), 15 SNOWWEB stations significantly increased the number of observation stations in the area to 19 during the 2014-15 austral summer. Collocated "virtual stations" created from AMPS output are combined with observations, producing a single dataset of zonal and meridional wind components used to train a self-organizing map (SOM). The resulting SOM is used to individually classify the observational and AMPS datasets, producing a time series of classifications for each dataset directly comparable to the other. Analysis of class composites shows two dominant weather patterns: low but directionally variable winds and high but directionally constant winds linked to the Ross Ice Shelf airstream (RAS). During RAS events the AMPS and SNOWWEB data displayed good temporal class alignment with good surface wind correlation. SOM analysis shows that AMPS did not accurately forecast surface-level wind speed or direction during light wind conditions where synoptic forcing was weak;however, it was able to forecast the low wind period occurrence accurately. Coggins's regimes provide synoptic-scale context and show a reduced synoptic pressure gradient during these classes, increasing reliance on the ability of Polar WRF to resolve mesoscale dynamics. Available initialization data have insufficient resolution for the region's complex topography, which likely impacts performance. The SOM analysis methods used are shown to be effective for model validation and are widely applicable.

关键词： Geographic location/entity Antarctica Circulation/ Dynamics Topographic effects observational techniques and algorithms Automatic weather stations Mathematical and statistical techniques Classification Forecasting Mesoscale forecasting Numerical weather prediction/forecasting

来源：评论

学校读者我要写书评

暂无评论

Cloud Discrimination from Sky Images Using a Clear-Sky Index

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第8期33卷 1583-1595页

作者： Saito, Masanori Iwabuchi, Hironobu Tohoku Univ Grad Sch Sci Ctr Atmospher & Ocean Studies Sendai Miyagi Japan

Cloud fraction mainly affects the incoming solar irradiance at the surface and is measured with ground based sky imagers. Although several methods enable cloud discrimination from digital sky images, cloud discrimination methods are still being developed to improve the classification accuracy. This study presents two methods for effective cloud discrimination from digital sky images using a newly defined clear-sky index (CSI). The CSI represents the degree of similarity of the spectral distribution to that expected for clear sky. In the advanced method (AM), the CSI is obtained from red green blue (RGB) signals in RAW format by linear transformation by taking into account the solar spectrum at the top of the atmosphere, the ozone transmittance, and the spectral response of the RGB channels. The simplified method (SM) uses digital signals in a JPEG format assuming prescribed color matching functions and atmospheric states. The AM can correctly classify broken gray clouds as cloud and aureole as clear sky in most cases, and it discriminates clear sky and clouds with a correct classification rate of 93.6% based on a comparison with the zenith-pointing lidar measurements. The SM demonstrates accurate cloud discrimination performance as well as the red-to-blue ratio method does. The use of RAW format data allows for more accurate image-based cloud discrimination.

关键词： algorithms Atm/Ocean Structure/ Phenomena Classification Cloud cover Clouds Mathematical and statistical techniques observational techniques and algorithms

来源：评论

学校读者我要写书评

暂无评论

Improvements in Detection of Light Precipitation with the Global Precipitation Measurement Dual-Frequency Precipitation Radar (GPM DPR)

引用

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY 2016年第4期33卷 653-667页

作者： Hamada, Atsushi Takayabu, Yukari N. Univ Tokyo Atmosphere & Ocean Res Inst 5-1-5 Kashiwanoha Kashiwa Chiba 2778568 Japan

This paper demonstrates the impact of the enhancement in detectability by the dual-frequency precipitation radar (DPR) on board the Global Precipitation Measurement (GPM) core observatory. By setting two minimum detectable refiectivities-12 and 18 dBZ-artificially to 6 months of GPM DPR measurements, the precipitation occurrence and volume increase by similar to 21.1% and similar to 1.9%, respectively, between 40 degrees S and 40 degrees N. GPM DPR is found to be able to detect light precipitation, which mainly consists of two distinct types. One type is shallow precipitation, which is most significant for convective precipitation over eastern parts of subtropical oceans, where deep convection is typically suppressed. The other type is probably associated with lower parts of anvil clouds associated with organized precipitation systems. While these echoes have lower reflectivities than the official value of the minimum detectable reflectivity, they are found to mostly consist of true precipitation signals, suggesting that the official value may be too conservative for some sort of meteorological analyses. These results are expected to further the understanding of both global energy and water budgets and the diabatic heating distribution.

关键词： Atm/Ocean Structure/ Phenomena Circulation/ Dynamics Convective storms observational techniques and algorithms Precipitation Radars/Radar observations Rainfall Satellite observations Stratiform clouds

来源：评论

学校读者我要写书评

暂无评论

Assimilation of Pseudo-GLM Data Using the Ensemble Kalman Filter

引用

MONTHLY WEATHER REVIEW 2016年第9期144卷 3465-3486页

作者： Allen, Blake J. Mansell, Edward R. Dowell, David C. Deierling, Wiebke Univ Oklahoma Cooperat Inst Mesoscale Meteorol Studies Norman OK 73019 USA NOAA Natl Severe Storms Lab OAR Norman OK 73069 USA NOAA Earth Syst Res Lab OAR Norman OK USA Natl Ctr Atmospher Res POB 3000 Boulder CO 80307 USA

Total lightning observations that will be available from the GOES-R Geostationary Lightning Mapper (GLM) have the potential to be useful in the initialization of convection-resolving numerical weather models, particularly in areas where other types of convective-scale observations are sparse or nonexistent. This study used the ensemble Kalman filter (EnKF) to assimilate real-data pseudo-GLM flash extent density (FED) observations at convection-resolving scale for a nonsevere multicell storm case (6 June 2000) and a tomadic supercell case (8 May 2003). For each case, pseudo-GLM FED observations were generated from ground-based lightning mapping array data with a spacing approximately equal to the nadir pixel width of the GLM, and tests were done to examine different FED observation operators and the utility of temporally averaging observations to smooth rapid variations in flash rates. The best results were obtained when assimilating 1-mM temporal resolution data using any of three observation operators that utilized graupel mass or graupel volume. Each of these three observation operators performed well for both the weak, disorganized convection of the multicell case and the much more intense convection of the supercell case. An observation operator using the noninductive charging rate performed poorly compared to the graupel mass and graupel volume operators, a result that appears likely to be due to the inability of the noninductive charging rate to account for advection of space charge after charge separation occurs.

关键词： Atm/Ocean Structure/ Phenomena Lightning observational techniques and algorithms Satellite observations Models and modeling Cloud resolving models Data assimilation Ensembles Numerical weather prediction/forecasting

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

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

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：