Consolidated Storm Prediction for Aviation (CoSPA)
Weather exerts a disruptive influence on aviation, both in the terminal area and en-route air traffic flow. Weather-related delays clearly increase during the convective weather season (approximately April through September), but also winter weather can cause havoc throughout the national airspace system. Reliable detection of hazardous weather and predictions thereof several hours in advance are essential for aviation users to achieve safe and efficient use of the airspace. Currently, weather avoidance is largely done in real-time responding to existing weather hazards (i.e., on a tactical basis) rather than through planning ahead based on anticipated weather (i.e., strategic decision). This is partly because of the weather forecast uncertainty and also because of a limited integration of weather information into automated air traffic management decision support tools.
The development of a Consolidated Storm Prediction for Aviation (CoSPA) product has been initiated by the Federal Aviation Administration (FAA) in order to replace a plethora of currently available weather forecast products by a single forecast to be used in all government-provided aviation weather systems. CoSPA will embody the best techniques available today, with an open modular architecture that enables easy exchange of algorithm modules, as new or upgraded techniques become available. CoSPA will build upon a mixture of observation-based expert systems and numerical weather prediction model to provide seamless 0 – 8 h forecasts of convective hazards and heavy snowfall. An initial forecast demonstration experiment of a CoSPA prototype will begin in summer 2008. CoSPA is a collaborative effort between the National Center for Atmospheric Research (NCAR), Massachusetts Institute of Technology (MIT) Lincoln Laboratory, and the NOAA Earth System Research Laboratory (ESRL) under sponsorship of the FAA.
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Probabilistic Weather Integration with Air Traffic Management
Probabilistic scenario forecast conceptWeather hazards are a major cause of aviation delays and flight cancellations. Strategic flight planning requires weather forecasts several hours into the future, which draws heavily upon numerical weather prediction. In particular, aviation users need 0 – 12 h forecasts that provide not only details about the likely weather outcome, but also information about storm structure, intensity, and organization, and associated forecast uncertainty. This emphasizes the need for short-range (0 – 2 days), high-resolution (<10 km spatial resolution) ensemble weather forecasting systems. Optimization of air traffic management, especially under future scenarios of anticipated much increased demand, has to build upon automated decision support tools that integrate probabilistic weather information to estimate airspace capacity and provide guidance for managing air traffic flows under consideration of the associated prediction uncertainties.
Under NASA sponsorship, the National Center for Atmospheric Research has been developing and refining new concepts of how probabilistic weather forecasts can be tailored for aviation needs and integrated with automated decision support tools. A novel approach has been established of how ensemble weather forecasts in the not-too-distant future may get analyzed from an aviation point of view and packaged for integration with automated air traffic management decision support tools. This new approach draws upon recent experience gained with probabilistic convective scenario forecasts. Although the focus has been on convective storms, primarily because of their disruptive influence on air traffic flows, the concepts developed there may be applicable to other en-route weather hazards, such as turbulence and icing, as well.
Nowcasting for Army Test and Evaluation Command (ATEC) Ranges
Lightning potential forecast The weather forecasting challenge for meteorologists at the ATEC ranges is to provide guidance for both tactical and strategic decisions. Ensuring safety of personnel and test operations is the primary focus of very short-term, 0 – 2 h weather forecasting (i.e., nowcasting). Another important aspect of weather forecasting is to find “windows of opportunity” throughout a day when range customers may expect weather conditions favorable for conducting their tests and minimizing weather-related downtime periods. Forecasters also assist their range customers in scheduling tests months in advance, which requires providing climatological information about the local weather conditions.
The AutoNowCaster (ANC) system is the primary tool used operationally by forecasters for monitoring and nowcasting of thunderstorm activity at the White Sands Missile Range (WSMR). The ANC system is a component of the ATEC Four-Dimensional Weather (4DWX) system, which is used by Army meteorologists to provide overall meteorological support. Partial ANC systems (so-called AN-Lite systems) that provide extrapolation-only forecasts are operational at other ATEC test centers as well, including the Aberdeen Test Center (ATC) in Maryland, the Redstone Technical Test Center (RTTC) in Alabama, Dugway Proving Ground (DPG) in Utah, and the Electronic Proving Ground (EPG) and Yuma Proving Ground (YPG) in Arizona. The forecast skills of the AN-Lite systems does not reach the performance level of a full ANC system, but a lack of or limited access to relevant observations currently prevents upgrades to full ANC systems at ATEC ranges other than WSMR.
Lightning is a particular safety concern at the ranges. A forecast product for the potential of storms to produce lightning has been developed and deployed at WSMR and EPG. This product provides lead times of approximately 5 – 15 min before lightning occurs. An example of this product is depicted together with vertical cross sections through storms. The red polygons enclose storms deemed capable of producing lightning (the lightning strikes that occurred within the next 20 min are shown by the red crosses).
Forecaster Over-the-Loop Evaluation (NWS & WSI)
The objective of this demonstration project under sponsorship by the National Weather Service (NWS) is to assess the potential benefits of human-added information to automatically generated short-term forecasts by the AutoNowCaster (ANC) for the Dallas/Ft. Worth aviation weather centers. In particular, the value of a forecaster entering boundaries and selecting the anticipated type of convective weather regime (i.e., specifically tuned weights for predictor fields) for improved overall system performance is assessed. A similar evaluation has been carried out over the Illinois/Indiana domain in collaboration with WSI. Efforts are underway by NCAR and the NWS to begin transfer of ANC components to the Advanced Weather Interactive Processing System (AWIPS).
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Beijing Meteorological Bureau (BMB) and Olympics 2008 Forecast Demonstration Project
The Institute of Urban Meteorology (IUM) of the Beijing Meteorological Bureau (BMB) and NCAR work collaboratively to transfer the AutoNowCaster (ANC) system to BMB, and develop it further to adapt to the local terrain and climate. As part of this multi-year project, NCAR scientists are collaborating with meteorologists from BMB to study the local characteristics of thunderstorm initiation and evolution for modifying and tuning the ANC algorithms to optimize its performance in the Beijing area, and to train the IUM staff on thunderstorm nowcasting techniques and the use of the ANC. VDRAS is a vital component of the BMB ANC installation. This is the first time for VDRAS to be installed in a domain with complex terrain. Preliminary results seem to indicate that VDRAS is able to handle complex terrain well. As part of this overall effort, NCAR staff will participate in the World Meteorological Organization (WMO) Beijing Olympics 2008 Forecast Demonstration Project (FDP). In addition to the ANC, also NCAR’s new Niwot blending system will be employed and operated as part of this project.
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Oceanic Weather
Remote, oceanic regions have severely limited data availability and, therefore, have few, if any, high resolution weather products that indicate current or future locations of convection. Convective hazards impact the safety, efficiency and economic viability of oceanic aircraft operations by producing turbulence, icing and lightning, and by necessitating aircraft rerouting while inflight, leading to higher fuel costs and delays. To improve convective products for the oceanic aviation community, the NASA-sponsored Oceanic Convection Diagnosis and Nowcasting project is focused on oceanic convective nowcasting over a 0 – 2 h period. Polar-orbiting and geostationary satellite observations are utilized in addition to global model results. Resulting products focus on the needs of pilots, dispatchers, air traffic managers and forecasters within the oceanic aviation community. Collaborators in this research include the National Center for Atmospheric Research (NCAR), the Naval Research Laboratory (NRL) at Monterey, and the Massachusetts Institute of Technology (MIT) Lincoln Laboratory.
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Winter Weather
Research activities related to winter weather are designed to improve the nowcast and forecast of winter weather conditions that impact aviation operations (e.g., deicing of aircraft, runway clearing, sanding, and plowing, and air traffic operations) at airports. These activities have focused on development of a machine to produce snow in a reliable and repeatable fashion in order to test deicing fluids; development of a hotplate snowgauge; evaluation of snowgauges; operation of a ground-based winter test facility at the Marshall field site; and support for operational Weather Support for Deicing Decision Makers (WSDDM) systems at several U.S. airports. Current sources of funding are the FAA Aviation Weather Research Program (AWRP), FAA Technical Center, NSF, and the City of Denver.
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Refractivity Experiment For H20 Research And Collaborative operational Technology Transfer (REFRACTT)
The lack of detailed, high-resolution water vapor measurements in the atmospheric boundary layer is one of the primary limiting factors in being able to predict convection initiation and produce accurate quantitative precipitation forecasts from numerical weather prediction models. During the summer of 2006, scientists took an important first step in addressing the need for an improved national, high-resolution moisture field by conducting the Refractivity Experiment For H20 Research And Collaborative operational Technology Transfer (REFRACTT). This effort is directed, not only toward improving our understanding of near-surface water vapor variability and the role it plays in the initiation of thunderstorms, but also on building operational advocacy for installing a new refractivity moisture retrieval technique on the national network of NEXRAD radars. This novel technique is based on measuring changes in the speed of radar signals to fixed targets caused by refraction, which in turn reveals variations in the atmospheric moisture content. REFRACTT yielded a wealth of data that are being analyzed now.
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