12 results on '"Wolff, D. B."'
Search Results
2. THE EMERGENCE OF OPEN-SOURCE SOFTWARE FOR THE WEATHER RADAR COMMUNITY
- Author
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Heistermann, M., Collis, S., Dixon, M. J., Giangrande, S., Helmus, J. J., Kelley, B., Koistinen, J., Michelson, D. B., Peura, M., Pfaff, T., and Wolff, D. B.
- Published
- 2015
3. Polarimetric Radar Verification of GPM Satellite-Based Retrievals of the Raindrop Size Distribution
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Petersen, Walter A, Tokay, Ali, Morris, K. R, D'adderio, L. P, Wolff, D. B, and Gatlin, P. N
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Meteorology And Climatology - Published
- 2017
4. High Resolution Observations of Drop Size Distribution for GPM Ground Validation
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Gatlin, Patrick N, Petersen, W. A, Carey, L. D, Wingo, M. T, Tokay, A, Bringi, V. N, Thurai, M, Wolff, D. B, and Phillips, D. W
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Meteorology And Climatology - Abstract
During the Mid-latitude Continental Convective Cloud Experiment (MC3E), NASA's GPM GV Disdrometer and Radar Observations of Precipitation (DROP) Facility deployed an array of disdrometers and rain gauges in northern Oklahoma to sample, with high resolution, the drop size distribution for use in development of precipitation retrieval algorithms for the GPM core satellites. The DROP Facility instruments deployed during MC3E consisted of 16 autonomous Parsivel units, 5 two-dimensional video disdrometers (2dvds), a vertically pointing K band radar, and 32 tipping bucket rain gauges. There were several rainfall events during MC3E in which rain drops exceeding 6 mm in diameter were recorded. The disdrometer array revealed large rain drops with diameters exceeding 6 mm and 8 mm during two separate stratiform and convective rainfall events, respectively. The NPOL radar, which was scanning in high resolution RHI mode (every 40 sec) over the disdrometer array during the stratiform event, indicated a 1 km thick bright band with a differential reflectivity column of 2-3 dB extending below the melting layer to the surface where the large drops were recorded by the 2dvds. These large drops are important for GPM since they can have a great impact upon satellite precipitation retrieval, especially near the ground and below heavy convective rainfall cores where satellites have had problems depicting the rainfall.
- Published
- 2012
5. Preparations for Global Precipitation Measurement(GPM)Ground Validation
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Bidwell, S. W, Bibyk, I. K, Duming, J. F, Everett, D. F, Smith, E. A, and Wolff, D. B
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Meteorology And Climatology - Abstract
The Global Precipitation Measurement (GPM) program is an international partnership led by the National Aeronautics and Space Administration (NASA) and the Japan Aerospace Exploration Agency (JAXA). GPM will improve climate, weather, and hydro-meterorological forecasts through more frequent and more accurate measurement of precipitation across the globe. This paper describes the concept and the preparations for Ground Validation within the GPM program. Ground Validation (GV) plays a critical role in the program by investigating and quantitatively assessing the errors within the satellite retrievals. These quantitative estimates of retrieval errors will assist the scientific community by bounding the errors within their research products. The two fundamental requirements of the GPM Ground Validation program are: (1) error characterization of the precipitation retrievals and (2) continual improvement of the satellite retrieval algorithms. These two driving requirements determine the measurements, instrumentation, and location for ground observations. This paper describes GV plans for estimating the systematic and random components of retrieval error and for characterizing the spatial and temporal structure of the error. This paper describes the GPM program for algorithm improvement in which error models are developed and experimentally explored to uncover the physical causes of errors within the retrievals. GPM will ensure that information gained through Ground Validation is applied to future improvements in the spaceborne retrieval algorithms. This paper discusses the potential locations for validation measurement and research, the anticipated contributions of GPM's international partners, and the interaction of Ground Validation with other GPM program elements.
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- 2004
6. Evolving Improvements to TRMM Ground Validation Rainfall Estimates
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Robinson, M, Kulie, M. S, Marks, D. A, Wolff, D. B, Ferrier, B. S, Amitai, E, Silberstein, D. S, Fisher, B. L, Wang, J, and Einaudi, Franco
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Meteorology And Climatology - Abstract
The primary function of the TRMM Ground Validation (GV) Program is to create GV rainfall products that provide basic validation of satellite-derived precipitation measurements for select primary sites. Since the successful 1997 launch of the TRMM satellite, GV rainfall estimates have demonstrated systematic improvements directly related to improved radar and rain gauge data, modified science techniques, and software revisions. Improved rainfall estimates have resulted in higher quality GV rainfall products and subsequently, much improved evaluation products for the satellite-based precipitation estimates from TRMM. This presentation will demonstrate how TRMM GV rainfall products created in a semi-automated, operational environment have evolved and improved through successive generations. Monthly rainfall maps and rainfall accumulation statistics for each primary site will be presented for each stage of GV product development. Contributions from individual product modifications involving radar reflectivity (Ze)-rain rate (R) relationship refinements, improvements in rain gauge bulk-adjustment and data quality control processes, and improved radar and gauge data will be discussed. Finally, it will be demonstrated that as GV rainfall products have improved, rainfall estimation comparisons between GV and satellite have converged, lending confidence to the satellite-derived precipitation measurements from TRMM.
- Published
- 2000
7. Rainfall Product Evaluation for the TRMM Ground Validation Program
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Amitai, E, Wolff, D. B, Robinson, M, Silberstein, D. S, Marks, D. A, Kulie, M. S, Fisher, B, and Einaudi, Franco
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Meteorology And Climatology - Abstract
Evaluation of the Tropical Rainfall Measuring Mission (TRMM) satellite observations is conducted through a comprehensive Ground Validation (GV) Program. Standardized instantaneous and monthly rainfall products are routinely generated using quality-controlled ground based radar data from four primary GV sites. As part of the TRMM GV program, effort is being made to evaluate these GV products and to determine the uncertainties of the rainfall estimates. The evaluation effort is based on comparison to rain gauge data. The variance between the gauge measurement and the true averaged rain amount within the radar pixel is a limiting factor in the evaluation process. While monthly estimates are relatively simple to evaluate, the evaluation of the instantaneous products are much more of a challenge. Scattegrams of point comparisons between radar and rain gauges are extremely noisy for several reasons (e.g. sample volume discrepancies, timing and navigation mismatches, variability of Z(sub e)-R relationships), and therefore useless for evaluating the estimates. Several alternative methods, such as the analysis of the distribution of rain volume by rain rate as derived from gauge intensities and from reflectivities above the gauge network will be presented. Alternative procedures to increase the accuracy of the estimates and to reduce their uncertainties also will be discussed.
- Published
- 2000
8. Climatological Processing and Product Development for the TRMM Ground Validation Program
- Author
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Marks, D. A, Kulie, M. S, Robinson, M, Silberstein, D. S, Wolff, D. B, Ferrier, B. S, Amitai, E, Fisher, B, Wang, J, Augustine, D, Thiele, O, and Einaudi, Franco
- Subjects
Meteorology And Climatology - Abstract
The Tropical Rainfall Measuring Mission (TRMM) satellite was successfully launched in November 1997.The main purpose of TRMM is to sample tropical rainfall using the first active spaceborne precipitation radar. To validate TRMM satellite observations, a comprehensive Ground Validation (GV) Program has been implemented. The primary goal of TRMM GV is to provide basic validation of satellite-derived precipitation measurements over monthly climatologies for the following primary sites: Melbourne, FL; Houston, TX; Darwin, Australia- and Kwajalein Atoll, RMI As part of the TRMM GV effort, research analysts at NASA Goddard Space Flight Center (GSFC) generate standardized rainfall products using quality-controlled ground-based radar data from the four primary GV sites. This presentation will provide an overview of TRMM GV climatological processing and product generation. A description of the data flow between the primary GV sites, NASA GSFC, and the TRMM Science and Data Information System (TSDIS) will be presented. The radar quality control algorithm, which features eight adjustable height and reflectivity parameters, and its effect on monthly rainfall maps, will be described. The methodology used to create monthly, gauge-adjusted rainfall products for each primary site will also be summarized. The standardized monthly rainfall products are developed in discrete, modular steps with distinct intermediate products. A summary of recently reprocessed official GV rainfall products available for TRMM science users will be presented. Updated basic standardized product results involving monthly accumulation, Z-R relationship, and gauge statistics for each primary GV site will also be displayed.
- Published
- 2000
9. Statistical Comparison of Algorithms
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Kedem, B., Wolff, D. B., Fokianos, Konstantinos, and Fokianos, Konstantinos [0000-0002-0051-711X]
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Computer science ,Carry (arithmetic) ,Reference distribution ,Data_MISCELLANEOUS ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Inference ,Radar engineering details ,C band radar ,Distortion ,Electrical and Electronic Engineering ,Meteorological radar ,S band radar ,Instrumentation ,Problem solving ,Mathematical models ,C-band radar ,Radar tracker ,Estimation theory ,Tropical rainfall measuring mission ,Vectors ,Reliability ,Empirical likelihood ,Probability distributions ,Distribution (mathematics) ,Exponential tilt ,Signal distortion ,Calibration ,S-band radar ,Regression analysis ,Algorithm ,Algorithms - Abstract
A "reference" algorithm or instrument and its various "distortions" are considered, where the distortions carry some valid information about the reference. The objective is to combine data from the reference and the distortions together in some manner in order to extract information from both the reference, as well as the distortions, and produce improved inference about the true reference algorithm. This is illustrated in terms of m precipitation radars and semiparametric estimation of the reference distribution and the distortion parameters. 53 3 770 776
- Published
- 2004
10. Utilization of a hybrid sequencing batch reactor (HSBR) as a decentralized system of domestic wastewater treatment
- Author
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da Costa, R. H. R., primary, Souto, V. S., primary, Prelhaz, A. T. S., primary, Neto, L. G. L., primary, and Wolff, D. B., primary
- Published
- 2008
- Full Text
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11. Performance and Kinectics Aspects of Nitrogen Removal in a Biofilm Sequencing Batch Reactor.
- Author
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Costa, R. H. R., Wolff, D. B., and Souto, V. S.
- Abstract
A biofilm sequencing batch reactor with a volume of 1.42 m
3 , nylon nets providing a 4,140 m2 /m3 support area for biofilms and an automated operation with 8 hour cycles was studied. The duration of the experiment was 135 days. Removal efficiencies e≧ 80% were obtained for carbonaceous matter, producing an effluent with 31±26.8 mg/L of filtered COD, 7±3.6 mg/L of BOD5 and 12±3.2 mg/L of TOC. The average removal efficiency of ammonium was 77 ± 16.6%, with a mean concentration in the effluent of 14 ± 10.2 mg NH4 -N/L. The denitrification efficiency was 80±14.7%. The effluent characteristics met the requirements of Brazilian environmental standard for discharge to receiving water bodies. A kinetic study of nitrification and denitrification showed that during the aerobic phase the specific rate of ammonium consumption was 0.057 g NH4 -N/g VSS.d and the production of NOx-N was 0.074 g NOx-N/g VSS.d, while the specific rate of NOx-N consumption was 0.05 g NOx-N/g VSS.d during the anoxic phase. The suspended and fixed biomass was composed of 50% ammonium-oxidizing bacteria (AOB). [ABSTRACT FROM AUTHOR]- Published
- 2013
12. Desempenho de Reatores Biológico Com Leito Móvel no Pós-Tratamento de Reator Anaeróbio
- Author
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SOUZA, F. V. R., COELHO, E. R. C., WOLFF, D. B., CAMPOS, R. H., and ZDRADEK, C. P.
- Abstract
Made available in DSpace on 2019-07-19T02:12:43Z (GMT). No. of bitstreams: 1 tese_12887_Dissertação FINAL Flávia Vitoi.pdf: 2417729 bytes, checksum: 4500cb064dd5eafd23f77788135b82b3 (MD5) Previous issue date: 2019-02-08 Esse trabalho avaliou o desempenho de um reator biológico com leito móvel (MBBR) como pós-tratamento de sistema anaeróbio, caracterizando o meio suporte utilizado e calculando os principais parâmetros utilizados para projeto de estações de tratamento de esgoto do tipo MBBR. O sistema de bancada funcionou durante 152 dias, e era composto por dois reatores MBBR que operam com quatro diferentes configurações, ou seja, com 2 e 4 horas de tempo de detenção hidráulica e com 50 e 70% de percentual de meio suporte. Os pilotos foram alimentados com efluente sintético com concentração de DQO afluente média de 200 mg/L e o oxigênio dissolvido do MBBR foi mantido em 2,0 mg/L. Foi realizada a caracterização do meio suporte utilizado, encontrando área superficial específica média de 507 m²/m³. A biomídia foi capaz de reter elevada quantidade de biomassa em sua superfície, atingindo valores de até 14,6 gSV/m², para a condição de 50% de recheio. A eficiência de remoção de DQO variou de 66,7% a 75,9%, porém, segundo teste ANOVA, não ocorreu diferença estatística significativa entre as quatro fases. A carga orgânica superficial aplicada (COS) variou de 4,69 a 10,28 gDQOt/m².dia, sendo observada relação linear com a eficiência do tratamento. Também foi observada a ocorrência da nitrificação parcial do efluente, atingindo até 45,9% de eficiência de remoção de nitrogênio amoniacal. Foi possível concluir que é viável utilizar um reator do tipo MBBR para o pós-tratamento de UASB, obtendo eficiência de remoção de DQO superior de 70%, atingindo eficiência global superior à 90%, sendo a opção mais vantajosa economicamente, que atende à premissa acima, com o TDH de 2,0 h e 50% de recheio.
- Published
- 2019
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