We have developed, tested, and operationally implemented a web based system for collecting and analyzing in nearreal time weather forecast and observational data to assess: (a) the performance of forecasts; and (b) the operational impacts of forecasts. A major goal of the system is to quantify the impacts of weather forecasts on the planning, execution, and outcomes of military operations. Our tests and implementation were focused on the METOC support provided by Naval Pacific Meteorology and Oceanography Detachment (NPMOD) Fallon to Naval Strike and Air Warfare Center (NSAWC) operations at Naval Air Station Fallon. Data are collected by NPMOD Fallon and entered via a web interface into a database at the Naval Postgraduate School (NPS) where the data are analyzed and results are reported in near-real time. The results include quantitative assessments of: (1) forecasts used in planning NSAWC missions; (2) changes made during mission planning in response to forecasted weather; (3) deviations from mission plans that occurred in response to weather conditions actually encountered; (4) positive and negative impacts on missions due to forecasts; (5) METOC Tactical Decision Aid forecast accuracy and mission impacts; and (6) forecast performance and mission impacts with respect to specific weather factors.

The effects of extended precision computing and other numerical techniques are evaluated for the Fourier matching method (FMM) acoustic scattering model, initially developed by Assistant Professor D. Benjamin Reeder, CDR/USN (NPS), and Professor Timothy K. Stanton (MIT/WHOI). Theory on acoustic scattering, reverberation, scattering models, conformal mapping, scatterer boundary conditions, floating point arithmetic, computational error, and extended precision computing is presented as a foundation for research development. The paper presents an assessment of the effects of numerical techniques on model output with the initial expectation of obtaining a more accurate, converged solution at higher frequencies, higher modal combinations, and greater eccentricities of scatterer shape. Comparisons to results from Reeder and Stanton (2004) demonstrate effects of executed techniques. Analysis includes an evaluation of the relationship between variable precision settings and computational time, gains in the useful frequency regime of the FMM, and numerical analysis benefits. Demonstrated techniques confirm that increased precision has a positive effect on model performance. The utility of other numerical techniques is discussed, and limitations of current computer systems and other shortfalls are illustrated. A feasibility assessment for Navy use of the FMM and recommendations for further improvements to the FMM are included.

The purpose of this study is to quantify patterns or trends of electromagnetic ducting conditions in the Arctic. On average, ducts occurred 5% of the time in the summer months, and 2-3% in the spring, fall, and winter months. This is considered a low approximation due to the vertical resolution of the sounding data. For some local regions, ducts occurred up to 20% of the time, especially in summer months. In general, local areas near coast lines or near the pole over ice/ocean had higher frequency of ducts than local areas over land mass. For summer and fall months, humidity gradients contributed most to the formation of a duct, while temperature gradients contributed to a lesser degree. For spring months, temperature gradients contributed most to the formation of the duct, while humidity gradients contributed to a lesser degree. For winter months, due to the extremely cold surface temperatures and low available humidity, temperature gradients were the dominant contribution to duct formation, and humidity gradients worked against duct formation.

e appears to be significant potential for improving climate forecasts for SWA. The DoD still relies on long-term means to create climatological planning products to the field. We feel that by incorporating the anomalies associated with the climate variations discussed here, the DoD could add significant value to its climatology products.

Within the Pacific Air Forces (PACAF) area of responsibility, tropical deep convection that is not associated with tropical cyclones can cause significant impacts to operations. In this study, convective indices calculated from five sites in the central and western tropical North Pacific are examined with respect to their ability to predict the onset and intensity of deep convection. Two predictands are utilized: measures of convection derived from surface weather observations and the Naval Research Laboratory (NRL) Blended Rainrate estimates, which are derived from infrared and microwave satellite observations and interpolated to the five sites. Eighteen indices derived from rawinsondes are ranked by predictive skill for specific locations and seasons. Indices that exhibit significant skill are used in a discriminant analysis to define a multivariate experimental tropical convective index, which is then evaluated for each region and season. The multivariate index was not able to discriminate between convective and non-convective environments over the central North Pacific. Although the multivariate index exhibited skill for sites in the tropical western North Pacific during summer, it did not perform better than the highest-ranked single indices. For many of the locations and seasons evaluated, the Severe Weather Threat (SWEAT) Index exhibited the most skill.

The Bomb Strike Experiment for Mine Countermeasure Operations, currently sponsored through the Office of Naval Research mine impact burial prediction project, is part of a multi-year, comprehensive effort aimed at enhancing the Navyâ s fleet naval mine clearance capability and success. The investigation discussed in this paper examines the experimental and theoretical characteristics of a rigid body falling through the air, water, and sediment column at high speed. Several experiments were conducted to launch bomb-like rigid bodies with the density ratio similar to operational munitions, namely the MK-84 general purpose bomb, into a hydrodynamic test tank. Careful observations of the bomb-like rigid bodyâ s position and orientation were collected and analyzed to produce a series of three-dimensional coordinate time-space data tables and plots. The resulting data set reveals a strong correlation between shape type and trajectory and dispersion patterns for rigid bodies moving through the water column at high velocity. This data will be used for numerical verification of the initial threedimensional model (STRIKE35) aimed at predicting the overall trajectory, maneuvering, burial depth and orientation of a falling high-velocity rigid body in the air-water-sediment column. The long-term goal of this project is to improve warhead lethality for use in quick, precise and accurate strikes on known enemy naval minefields in the littoral combat environment. / FUNDED BY: N0001406WR20076

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Präsentation der Forschungsergebnisse aus dem Institut für Meteorologie der Universität Leipzig und dem Leibniz-Institut für Troposphärenforschung

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The relevance of ship based routeing is discussed. Data collected at sea are analysed to produce vessel response characteristics Meteorological data are analysed in a conventional manner to establish effective steering criteria with respect to 500 mb flow. For the first time a routeing model is formulated which recognises the three spatial dimensions of a middle latitude storm. A theoretical analysis of relative flow in a growing baroclinic wave is undertaken. Reference to displacement of the wave trough affords a measure of both storm development and steering effectiveness. Short, medium and long term planning elements are combined in a model. The effectiveness of this approach is demonstrated by actually "weather routeing" a vessel, whilst comparing progress of a sister ship navigated conventionally. Sources of error and limitations of the model are discussed.