374 research outputs found

    Wake Vortex Research in the USA (WakeNet-USA)

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    This viewgraph presentation reviews the cooperative work that FAA and NASA are engaged in to safely increase the capacity of the National Airspace System by studying the wake vortex operations. Wake vortex avoidance is a limiting factor in defining separation standards in the airport terminal area and could become a reducing separation standards in en route airspace

    Comparing ASCAT and CYGNSS Winds near Tropical Convection

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    Gradient Features identified in ASCAT (Advanced Scatterometer) data correspond well to observed CYGNSS (Cyclone Global Navigation Satellite System) wind shifts: Comparing ASCAT and CYGNSS winds near tropical convection. Gradient wind magnitude in ASCAT observations has been recently shown to be a useful proxy for the presence of tropical convection cold pools. To help confirm this in the vicinity of precipitation we perform a comparison with the L-band CYGNSS wind dataset. Integrated Multi-satellite Retrievals for GPM (Global Precipitation Measurement)) IMERG

    Lessons from New York City’s Struggle Against Amazon HQ2 in Long Island City

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    For three months between November 2018 and February 2019, the entire world, it seemed, was watching Long Island City, Queens. On November 12, 2018, nearly two years after Amazon announced that the company would be holding a contest for its second corporate headquarters (Amazon HQ2), New York City Mayor Bill de Blasio and New York State Governor Andrew Cuomo jointly announced that Amazon had selected Long Island City as one of its two HQ2 locations. The project, outlined in a Memorandum of Understanding (MOU) between Amazon and New York City and State, would provide up to 3billioninpublic(stateandcity)subsidiestoAmazoninexchangeforbuilding4–8millionsquarefeetofofficespaceontheEastRiverwaterfrontandcreating25,000jobsaveraging3 billion in public (state and city) subsidies to Amazon in exchange for building 4–8 million square feet of office space on the East River waterfront and creating 25,000 jobs averaging 150,000 per year (over ten years). However, fierce opposition to the plan quickly emerged. As the buzz (and controversy) concerning Amazon HQ2 continued to grow, the next two months witnessed a series of public events dedicated to the Amazon plan—including meetings, discussions, teach-ins, city council hearings, canvassing operations, Internet discussion forums, and protests. Then suddenly, on Valentine’s Day, in a tersely worded statement Amazon announced that it was no longer planning to build its second headquarters in Long Island City. The shock waves from this second surprise decision emerged immediately and continue to reverberate today. But while we may never know the true reason(s) for this decision, the struggle over the project and Amazon’s attempt to control and manage community engagement in the planning process are instructive in their own right. From the arguments that emerged both for and against the Amazon plan we can discern the contours of the emerging struggles over urban space between big tech, the state, and immigrant and working-class communities in global cities such as New York City. The Amazon experience in Long Island City also sheds light on the power of organizing across multiple issue areas in struggles against big tech’s designs on the contemporary city

    Exploring the Utility of the Planned CYGNSS Mission for Investigating the Initiation and Development of the Madden-Julian Oscillation

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    CYGNSS is a planned constellation consisting of multiple micro-satellites that leverage the Global Positioning System (GPS) to provide rapidly updated, high resolution (approx. 15-50 km, approx. 4 h) surface wind speeds (via bi-static scatterometry) over the tropical oceans in any weather condition, including heavy rainfall. The approach of the work to be presented at this conference is to utilize a limited-domain, cloud-system resolving model (Weather Research and Forecasting or WRF) and its attendant data assimilation scheme (Three-Dimensional Variational Assimilation or 3DVAR) to investigate the utility of the CYGNSS mission for helping characterize key convectiveto- mesoscale processes - such as surface evaporation, moisture advection and convergence, and upscale development of precipitation systems - that help drive the initiation and development of the Madden-Julian Oscillation (MJO) in the equatorial Indian Ocean. The proposed work will focus on three scientific objectives. Objective 1 is to produce a high-resolution surface wind dataset resolution (approx. 0.5 h, approx. 1-4 km) for multiple MJO onsets using WRF-assimilated winds and other data from the DYNAmics of the MJO (DYNAMO) field campaign, which took place during October 2011 - March 2012. Objective 2 is to study the variability of surface winds during MJO onsets at temporal and spatial scales of finer resolution than future CYGNSS data. The goal is to understand how sub-CYGNSS-resolution processes will shape the observations made by the satellite constellation. Objective 3 is to ingest simulated CYGNSS data into the WRF model in order to perform observing system simulation experiments (OSSEs). These will be used to test and quantify the potential beneficial effects provided by CYGNSS, particularly for characterizing the physical processes driving convective organization and upscale development during the initiation and development of the MJO. The proposed research is ideal for answering important questions about the CYGNSS mission, such as the representativeness of surface wind retrievals in the context of the complex airflow processes that occur during heavy precipitation, as well as the tradeoffs in retrieval accuracy that result from finer spatial resolution of the CYGNSS winds versus increased errors/noisiness in those data. Research plans and initial progress toward these objectives will be presented

    Mimesis stories: composing new nature music for the shakuhachi

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    Nature is a widespread theme in much new music for the shakuhachi (Japanese bamboo flute). This article explores the significance of such music within the contemporary shakuhachi scene, as the instrument travels internationally and so becomes rooted in landscapes outside Japan, taking on the voices of new creatures and natural phenomena. The article tells the stories of five compositions and one arrangement by non-Japanese composers, first to credit composers’ varied and personal responses to this common concern and, second, to discern broad, culturally syncretic traditions of nature mimesis and other, more abstract, ideas about the naturalness of sounds and creative processes (which I call musical naturalism). Setting these personal stories and longer histories side by side reveals that composition creates composers (as much as the other way around). Thus it hints at much broader terrain: the refashioning of human nature at the confluence between cosmopolitan cultural circulations and contemporary encounters with the more-than-human world

    Production of Lightning NO(x) and its Vertical Distribution Calculated from 3-D Cloud-scale Chemical Transport Model Simulations

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    A 3-D cloud scale chemical transport model that includes a parameterized source of lightning NO(x), based on observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms observed during four field projects. Production per intracloud (P(sub IC) and cloud-to-ground (P(sub CG)) flash is estimated by assuming various values of P(sub IC) and P(sub CG) for each storm and determining which production scenario yields NO(x) mixing ratios that compare most favorably with in-cloud aircraft observations. We obtain a mean P(sub CG) value of 500 moles NO (7 kg N) per flash. The results of this analysis also suggest that on average, P(sub IC) may be nearly equal to P(sub CG), which is contrary to the common assumption that intracloud flashes are significantly less productive of NO than are cloud-to-ground flashes. This study also presents vertical profiles of the mass of lightning NO(x), after convection based on 3-D cloud-scale model simulations. The results suggest that following convection, a large percentage of lightning NO(x), remains in the middle and upper troposphere where it originated, while only a small percentage is found near the surface. The results of this work differ from profiles calculated from 2-D cloud-scale model simulations with a simpler lightning parameterization that were peaked near the surface and in the upper troposphere (referred to as a "C-shaped" profile). The new model results (a backward C-shaped profile) suggest that chemical transport models that assume a C-shaped vertical profile of lightning NO(x) mass may place too much mass neat the surface and too little in the middle troposphere
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