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  • 1
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    De novo computational design of retro-aldol enzymes (2008)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2008-03-08
    Description: The creation of enzymes capable of catalyzing any desired chemical reaction is a grand challenge for computational protein design. Using new algorithms that rely on hashing techniques to construct active sites for multistep reactions, we designed retro-aldolases that use four different catalytic motifs to catalyze the breaking of a carbon-carbon bond in a nonnatural substrate. Of the 72 designs that were experimentally characterized, 32, spanning a range of protein folds, had detectable retro-aldolase activity. Designs that used an explicit water molecule to mediate proton shuffling were significantly more successful, with rate accelerations of up to four orders of magnitude and multiple turnovers, than those involving charged side-chain networks. The atomic accuracy of the design process was confirmed by the x-ray crystal structure of active designs embedded in two protein scaffolds, both of which were nearly superimposable on the design model.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431203/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431203/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jiang, Lin -- Althoff, Eric A -- Clemente, Fernando R -- Doyle, Lindsey -- Rothlisberger, Daniela -- Zanghellini, Alexandre -- Gallaher, Jasmine L -- Betker, Jamie L -- Tanaka, Fujie -- Barbas, Carlos F 3rd -- Hilvert, Donald -- Houk, Kendall N -- Stoddard, Barry L -- Baker, David -- R01 CA097328/CA/NCI NIH HHS/ -- R01 GM049857/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2008 Mar 7;319(5868):1387-91. doi: 10.1126/science.1152692.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18323453" target="_blank"〉PubMed〈/a〉
    Keywords: Aldehyde-Lyases/*chemistry/metabolism ; *Algorithms ; Binding Sites ; Catalysis ; Catalytic Domain ; Computer Simulation ; Crystallography, X-Ray ; Hydrogen Bonding ; Hydrophobic and Hydrophilic Interactions ; Kinetics ; Models, Molecular ; Protein Conformation ; Protein Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 2
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    Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements (2007)
    In:  CASI
    Details
    Publication Date: 2018-06-06
    Description: This paper describes the retrievals algorithm used to determine temperature and height from radiance measurements by the Microwave Limb Sounder on EOS Aura. MLS is a "limbscanning" instrument, meaning that it views the atmosphere along paths that do not intersect the surface - it actually looks forwards from the Aura satellite. This means that the temperature retrievals are for a "profile" of the atmosphere somewhat ahead of the satellite. Because of the need to view a finite sample of the atmosphere, the sample spans a box about 1.5km deep and several tens of kilometers in width; the optical characteristics of the atmosphere mean that the sample is representative of a tube about 200-300km long in the direction of view. The retrievals use temperature analyses from NASA's Goddard Earth Observing System, Version 5 (GEOS-5) data assimilation system as a priori states. The temperature retrievals are somewhat deperrde~zt on these a priori states, especially in the lower stratosphere. An important part of the validation of any new dataset involves comparison with other, independent datasets. A large part of this study is concerned with such comparisons, using a number of independent space-based measurements obtained using different techniques, and with meteorological analyses. The MLS temperature data are shown to have biases that vary with height, but also depend on the validation dataset. MLS data are apparently biased slightly cold relative to correlative data in the upper troposphere and slightly warm in the middle stratosphere. A warm MLS bias in the upper stratosphere may be due to a cold bias in GEOS-5 temperatures.
    Keywords: Meteorology and Climatology
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  • 3
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    Cancer-associated IDH1 mutations produce 2-hydroxyglutarate (2009)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2009-11-26
    Description: Mutations in the enzyme cytosolic isocitrate dehydrogenase 1 (IDH1) are a common feature of a major subset of primary human brain cancers. These mutations occur at a single amino acid residue of the IDH1 active site, resulting in loss of the enzyme's ability to catalyse conversion of isocitrate to alpha-ketoglutarate. However, only a single copy of the gene is mutated in tumours, raising the possibility that the mutations do not result in a simple loss of function. Here we show that cancer-associated IDH1 mutations result in a new ability of the enzyme to catalyse the NADPH-dependent reduction of alpha-ketoglutarate to R(-)-2-hydroxyglutarate (2HG). Structural studies demonstrate that when arginine 132 is mutated to histidine, residues in the active site are shifted to produce structural changes consistent with reduced oxidative decarboxylation of isocitrate and acquisition of the ability to convert alpha-ketoglutarate to 2HG. Excess accumulation of 2HG has been shown to lead to an elevated risk of malignant brain tumours in patients with inborn errors of 2HG metabolism. Similarly, in human malignant gliomas harbouring IDH1 mutations, we find markedly elevated levels of 2HG. These data demonstrate that the IDH1 mutations result in production of the onco-metabolite 2HG, and indicate that the excess 2HG which accumulates in vivo contributes to the formation and malignant progression of gliomas.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818760/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2818760/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dang, Lenny -- White, David W -- Gross, Stefan -- Bennett, Bryson D -- Bittinger, Mark A -- Driggers, Edward M -- Fantin, Valeria R -- Jang, Hyun Gyung -- Jin, Shengfang -- Keenan, Marie C -- Marks, Kevin M -- Prins, Robert M -- Ward, Patrick S -- Yen, Katharine E -- Liau, Linda M -- Rabinowitz, Joshua D -- Cantley, Lewis C -- Thompson, Craig B -- Vander Heiden, Matthew G -- Su, Shinsan M -- P01 CA104838/CA/NCI NIH HHS/ -- P01 CA104838-05/CA/NCI NIH HHS/ -- P30 EB009998/EB/NIBIB NIH HHS/ -- R01 CA105463/CA/NCI NIH HHS/ -- R01 CA105463-06/CA/NCI NIH HHS/ -- R21 CA128620/CA/NCI NIH HHS/ -- England -- Nature. 2009 Dec 10;462(7274):739-44. doi: 10.1038/nature08617. Epub .〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Agios Pharmaceuticals, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19935646" target="_blank"〉PubMed〈/a〉
    Keywords: Arginine/genetics ; Brain Neoplasms/*genetics/*metabolism/pathology ; Catalytic Domain ; Cell Line ; Crystallography, X-Ray ; Disease Progression ; Enzyme Assays ; Glioma/genetics/metabolism/pathology ; Glutarates/*metabolism ; Histidine/genetics/metabolism ; Humans ; Isocitrate Dehydrogenase/*genetics/*metabolism ; Ketoglutaric Acids/metabolism ; Models, Molecular ; Mutant Proteins/*genetics/*metabolism ; Mutation/genetics ; Protein Conformation
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 4
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    Variable control of Ets-1 DNA binding by multiple phosphates in an unstructured region (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-07-05
    Description: Cell signaling that culminates in posttranslational modifications directs protein activity. Here we report how multiple Ca2+-dependent phosphorylation sites within the transcription activator Ets-1 act additively to produce graded DNA binding affinity. Nuclear magnetic resonance spectroscopic analyses show that phosphorylation shifts Ets-1 from a dynamic conformation poised to bind DNA to a well-folded inhibited state. These phosphates lie in an unstructured flexible region that functions as the allosteric effector of autoinhibition. Variable phosphorylation thus serves as a "rheostat" for cell signaling to fine-tune transcription at the level of DNA binding.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pufall, Miles A -- Lee, Gregory M -- Nelson, Mary L -- Kang, Hyun-Seo -- Velyvis, Algirdas -- Kay, Lewis E -- McIntosh, Lawrence P -- Graves, Barbara J -- GM08537/GM/NIGMS NIH HHS/ -- P01-CA24014/CA/NCI NIH HHS/ -- R01 GM38663/GM/NIGMS NIH HHS/ -- T32-CA93247/CA/NCI NIH HHS/ -- New York, N.Y. -- Science. 2005 Jul 1;309(5731):142-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Huntsman Cancer Institute, Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112-5550, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15994560" target="_blank"〉PubMed〈/a〉
    Keywords: Allosteric Regulation ; Amino Acid Sequence ; Amino Acid Substitution ; Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases/metabolism ; DNA/*metabolism ; Hydrophobic and Hydrophilic Interactions ; Mice ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Nuclear Magnetic Resonance, Biomolecular ; Phosphorylation ; Protein Binding ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary ; Protein Structure, Tertiary ; Proto-Oncogene Protein c-ets-1 ; Proto-Oncogene Proteins/*chemistry/genetics/*metabolism ; Proto-Oncogene Proteins c-ets ; Signal Transduction ; Transcription Factors/*chemistry/genetics/*metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 5
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    Assistance of microbial glycolipid antigen processing by CD1e (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-11-29
    Description: Complexes between CD1 molecules and self or microbial glycolipids represent important immunogenic ligands for specific subsets of T cells. However, the function of one of the CD1 family members, CD1e, has yet to be determined. Here, we show that the mycobacterial antigens hexamannosylated phosphatidyl-myo-inositols (PIM6) stimulate CD1b-restricted T cells only after partial digestion of the oligomannose moiety by lysosomal alpha-mannosidase and that soluble CD1e is required for this processing. Furthermore, recombinant CD1e was able to bind glycolipids and assist in the digestion of PIM6. We propose that, through this form of glycolipid editing, CD1e helps expand the repertoire of glycolipidic T cell antigens to optimize antimicrobial immune responses.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉de la Salle, Henri -- Mariotti, Sabrina -- Angenieux, Catherine -- Gilleron, Martine -- Garcia-Alles, Luis-Fernando -- Malm, Dag -- Berg, Thomas -- Paoletti, Samantha -- Maitre, Blandine -- Mourey, Lionel -- Salamero, Jean -- Cazenave, Jean Pierre -- Hanau, Daniel -- Mori, Lucia -- Puzo, Germain -- De Libero, Gennaro -- New York, N.Y. -- Science. 2005 Nov 25;310(5752):1321-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉INSERM, U725, Etablissement Francais du Sang-Alsace, F-67065 Strasbourg, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16311334" target="_blank"〉PubMed〈/a〉
    Keywords: Acylation ; *Antigen Presentation ; Antigen-Presenting Cells/immunology ; Antigens, Bacterial/*immunology/*metabolism ; Antigens, CD1/chemistry/genetics/immunology/*metabolism ; Cell Line, Tumor ; Dendritic Cells/enzymology/immunology ; Glycolipids/*immunology/metabolism ; Humans ; Hydrogen-Ion Concentration ; Lymphocyte Activation ; Models, Molecular ; Mycobacterium tuberculosis/immunology ; Phosphatidylinositols/*immunology/*metabolism ; Protein Conformation ; Recombinant Proteins/immunology/metabolism ; Solubility ; T-Lymphocytes/immunology ; Transfection ; alpha-Mannosidase/immunology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
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    Structural basis of immune evasion at the site of CD4 attachment on HIV-1 gp120 (2009)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2009-12-08
    Description: The site on HIV-1 gp120 that binds to the CD4 receptor is vulnerable to antibodies. However, most antibodies that interact with this site cannot neutralize HIV-1. To understand the basis of this resistance, we determined co-crystal structures for two poorly neutralizing, CD4-binding site (CD4BS) antibodies, F105 and b13, in complexes with gp120. Both antibodies exhibited approach angles to gp120 similar to those of CD4 and a rare, broadly neutralizing CD4BS antibody, b12. Slight differences in recognition, however, resulted in substantial differences in F105- and b13-bound conformations relative to b12-bound gp120. Modeling and binding experiments revealed these conformations to be poorly compatible with the viral spike. This incompatibility, the consequence of slight differences in CD4BS recognition, renders HIV-1 resistant to all but the most accurately targeted antibodies.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862588/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862588/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Chen, Lei -- Kwon, Young Do -- Zhou, Tongqing -- Wu, Xueling -- O'Dell, Sijy -- Cavacini, Lisa -- Hessell, Ann J -- Pancera, Marie -- Tang, Min -- Xu, Ling -- Yang, Zhi-Yong -- Zhang, Mei-Yun -- Arthos, James -- Burton, Dennis R -- Dimitrov, Dimiter S -- Nabel, Gary J -- Posner, Marshall R -- Sodroski, Joseph -- Wyatt, Richard -- Mascola, John R -- Kwong, Peter D -- Z99 AI999999/Intramural NIH HHS/ -- New York, N.Y. -- Science. 2009 Nov 20;326(5956):1123-7. doi: 10.1126/science.1175868.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19965434" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Antibodies, Neutralizing/chemistry/*immunology/metabolism ; Antigens, CD4/chemistry/*metabolism ; Binding Sites ; Binding Sites, Antibody ; Crystallography, X-Ray ; Epitopes ; HIV Antibodies/*chemistry/*immunology/metabolism ; HIV Envelope Protein gp120/*chemistry/*immunology/metabolism ; Hiv-1 ; Humans ; Hydrophobic and Hydrophilic Interactions ; *Immune Evasion ; Models, Molecular ; Molecular Sequence Data ; Peptide Fragments/chemistry/immunology/metabolism ; Protein Conformation
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
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    Comprehensive mapping of long-range interactions reveals folding principles of the human genome (2009)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2009-10-10
    Description: We describe Hi-C, a method that probes the three-dimensional architecture of whole genomes by coupling proximity-based ligation with massively parallel sequencing. We constructed spatial proximity maps of the human genome with Hi-C at a resolution of 1 megabase. These maps confirm the presence of chromosome territories and the spatial proximity of small, gene-rich chromosomes. We identified an additional level of genome organization that is characterized by the spatial segregation of open and closed chromatin to form two genome-wide compartments. At the megabase scale, the chromatin conformation is consistent with a fractal globule, a knot-free, polymer conformation that enables maximally dense packing while preserving the ability to easily fold and unfold any genomic locus. The fractal globule is distinct from the more commonly used globular equilibrium model. Our results demonstrate the power of Hi-C to map the dynamic conformations of whole genomes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858594/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2858594/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lieberman-Aiden, Erez -- van Berkum, Nynke L -- Williams, Louise -- Imakaev, Maxim -- Ragoczy, Tobias -- Telling, Agnes -- Amit, Ido -- Lajoie, Bryan R -- Sabo, Peter J -- Dorschner, Michael O -- Sandstrom, Richard -- Bernstein, Bradley -- Bender, M A -- Groudine, Mark -- Gnirke, Andreas -- Stamatoyannopoulos, John -- Mirny, Leonid A -- Lander, Eric S -- Dekker, Job -- HG003143/HG/NHGRI NIH HHS/ -- R01 HG003143/HG/NHGRI NIH HHS/ -- R01 HG003143-06/HG/NHGRI NIH HHS/ -- R01HL06544/HL/NHLBI NIH HHS/ -- R37DK44746/DK/NIDDK NIH HHS/ -- T32 HG002295/HG/NHGRI NIH HHS/ -- U54HG004592/HG/NHGRI NIH HHS/ -- New York, N.Y. -- Science. 2009 Oct 9;326(5950):289-93. doi: 10.1126/science.1181369.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Broad Institute of Harvard and Massachusetts Institute of Technology (MIT), MA 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19815776" target="_blank"〉PubMed〈/a〉
    Keywords: Biotin ; Cell Line, Transformed ; Cell Nucleus/*ultrastructure ; Chromatin/*chemistry ; Chromatin Immunoprecipitation ; *Chromosomes, Human/chemistry/ultrastructure ; Computational Biology ; DNA/*chemistry ; Gene Library ; *Genome, Human ; Humans ; In Situ Hybridization, Fluorescence ; Models, Molecular ; Monte Carlo Method ; Nucleic Acid Conformation ; Principal Component Analysis ; Protein Conformation ; Sequence Analysis, DNA
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    Diagnostic Comparison of Meteorological Analyses during the 2002 Antarctic Winter (2005)
    In:  Other Sources
    Details
    Publication Date: 2018-06-11
    Description: Several meteorological datasets, including U.K. Met Office (MetO), European Centre for Medium-Range Weather Forecasts (ECMWF), National Centers for Environmental Prediction (NCEP), and NASA's Goddard Earth Observation System (GEOS-4) analyses, are being used in studies of the 2002 Southern Hemisphere (SH) stratospheric winter and Antarctic major warming. Diagnostics are compared to assess how these studies may be affected by the meteorological data used. While the overall structure and evolution of temperatures, winds, and wave diagnostics in the different analyses provide a consistent picture of the large-scale dynamics of the SH 2002 winter, several significant differences may affect detailed studies. The NCEP-NCAR reanalysis (REAN) and NCEP-Department of Energy (DOE) reanalysis-2 (REAN-2) datasets are not recommended for detailed studies, especially those related to polar processing, because of lower-stratospheric temperature biases that result in underestimates of polar processing potential, and because their winds and wave diagnostics show increasing differences from other analyses between similar to 30 and 10 hPa (their top level). Southern Hemisphere polar stratospheric temperatures in the ECMWF 40-Yr Re-analysis (ERA-40) show unrealistic vertical structure, so this long-term reanalysis is also unsuited for quantitative studies. The NCEP/Climate Prediction Center (CPC) objective analyses give an inferior representation of the upper-stratospheric vortex. Polar vortex transport barriers are similar in all analyses, but there is large variation in the amount, patterns, and timing of mixing, even among the operational assimilated datasets (ECMWF, MetO, and GEOS-4). The higher-resolution GEOS-4 and ECMWF assimilations provide significantly better representation of filamentation and small-scale structure than the other analyses, even when fields gridded at reduced resolution are studied. The choice of which analysis to use is most critical for detailed transport studies (including polar process modeling) and studies involving synoptic evolution in the upper stratosphere. The operational assimilated datasets are better suited for most applications than the NCEP/CPC objective analyses and the reanalysis datasets.
    Keywords: Meteorology and Climatology
    Type: Monthly Weather Review; Volume 133; Issue 5; 1261-1278
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  • 9
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    Simulation of the Impact of New Aircraft and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses (2008)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Accurate observations of surface ocean vector winds (OVW) with high spatial and temporal resolution are required for understanding and predicting tropical cyclones. As NASA's QuikSCAT and Navy's WindSat operate beyond their design life, many members of the weather and climate science communities recognize the importance of developing new observational technologies and strategies to meet the essential need for OVW information to improve hurricane intensity and location forecasts. The Hurricane Imaging Radiometer (HIRAD) is an innovative technology development which offers new and unique remotely sensed satellite observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR), which is the only proven remote sensing technique for observing tropical cyclone (TC) ocean surface wind speeds and rain rates. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology. This sensor will operate over 4-7 GHz (C-band frequencies) where the required TC remote sensing physics has been validated by both SFMR and WindSat radiometers. The instrument is described in more detail in a paper by Jones et al. presented to the Tropical Meteorology Special Symposium at this AMS Annual Meeting. Simulated HIRAD passes through a simulation of hurricane Frances are being developed to demonstrate HIRAD estimation of surface wind speed over a wide swath in the presence of heavy rain. These are currently being used in "quick" OSSEs (Observing System Simulation Experiments) with H'Wind analyses as the discriminating tool. The H'Wind analysis, a product of the Hurricane Research Division of NOAA's Atlantic , Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa._ov/hrd/data sub/wind.html. Observations have been simulated from both aircraft altitudes and space. The simulated flight patterns for the aircraft platform cases have been designed to duplicate the timing and flight patterns used in routine NOAA and USAF hurricane surveillance flights, and the spaceborne case simulates a TRMM orbit and altitude.
    Keywords: Meteorology and Climatology
    Type: 12th Conference on IOAS-AOLS as part of the 2008 AMS 88th Annual Meeting; Jan 20, 2008 - Jan 24, 2008; New Orleans, LA; United States
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  • 10
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    Reactive Nitrogen Distribution and Partitioning in the North American Troposphere and Lowermost Stratosphere (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A comprehensive group of reactive nitrogen species (NO, NO2, HNO3, HO2NO2, PANs, alkyl nitrates, and aerosol-NO3) were measured in the troposphere and lowermost stratosphere over North America and the Atlantic during July/August 2004 (INTEX-A) from the NASA DC-8 platform (0.1-12 km). Less reactive nitrogen species (HCN and CH3CN), that are also unique tracers of biomass combustion, were also measured along with a host of other gaseous (CO, VOC, OVOC, halocarbon) and aerosol tracers. Clean background air as well as air with influences from biogenic emissions, anthropogenic pollution, biomass combustion, and stratosphere was sampled both over continental U. S., Atlantic and Pacific. The North American upper troposphere was found to be greatly influenced by both lightning NO(x) and surface pollution lofted via convection and contained elevated concentrations of PAN, ozone, hydrocarbons, and NO(x). Under polluted conditions PAN was a dominant carrier of reactive nitrogen in the upper troposphere while nitric acid dominated in the lower troposphere. Peroxynitric acid (HO2NO2) was present in sizable concentrations always peaking at around 8 km. Aerosol nitrate appeared to be mostly contained in large soil based particles in the lower troposphere. Plumes from Alaskan fires contained large amounts of PAN and very little enhancement in ozone. Observational data suggest that lightning was a far greater contributor to NO(x) in the upper troposphere than previously believed. NO(x) and NO(y) reservoir appeared to be in steady state only in the middle troposphere where NO(x)/NO(y) was independent of air mass age. A first comparison of observed data with simulations from four 3-D models shows significant differences between observations and models as well as among models. These uncertainties likely propagate themselves in satellites derived NOx data. Observed data are interpreted to suggest that soil sinks of HCN/CH3CN are at best very small. We investigate the partitioning and interplay of the reactive nitrogen species within characteristic air masses and further examine their role in ozone formation.
    Keywords: Meteorology and Climatology
    Type: Submitted to the Journal of Geophysical Research to be published in volume 112, pp. 1-15, April 2007
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