Abstract:
A new method and system for generating probabilities of objective values of hazards as a fine granularity grid in four dimensions (three spatial dimensions plus time) to be used by decision support and visualization tools. Utilizing the proposed system, proxies for hazard data received at different times and in different formats may be used as input data to a grid of intelligent software agents which generate a four dimensional matrix of probabilities of objective values of hazards. The method allows for proxies and/or subjective information on hazards that may arrive asynchronously and with coarse temporal and spatial accuracy to be converted into a standard fine granularity four dimensional hazard probability grid. The grid is created automatically, without the need for expert human interpretation, can provide visualization of the four dimensional hazard volumes and may be used directly by decision support tools without the need for expert human interpretation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to the field of risk management. More specifically, the invention comprises a method and a system for extracting hazard information from forecast data having varied temporal and spatial accuracies. 
         [0003]    2. Description of the Related Art 
         [0004]    Hazards and the use of hazard predictions are a significant concern for many industries, especially the aviation industry. Accordingly, the present invention is described and considered as it applies to aviation. The description of the related art will also refer generally to the aviation application. However, in reading this entire disclosure, the reader should bear in mind that the methods disclosed can be applied to many areas beyond aviation. 
         [0005]    The general approach to hazard prediction in the aviation industry has been to utilize forecast data and other weather products which are commonly shared among various “users,” such as dispatchers, pilots, and controllers. Each of the users works to ensure that the aircraft avoids flying in unacceptably hazardous weather. 
         [0006]    The weather information is generated by weather forecasters in various formats (textual, graphical, or as gridded values or probabilities in large increments of time). The weather may be “observations” of weather as it was at a particular time, which by the time of receipt is actually in the past. Alternatively, weather information may be supplied as “forecasts.” Forecasts are normally generated for periods of time into the future, again set in large increments of time (from several hours to several days). Forecasts generally describe the expected weather conditions rather than actual hazards. 
         [0007]    These weather products in their current form require human interpretation. Furthermore, meaningful and accurate interpretation requires significant skill and experience. The aircraft operators are primarily interested in weather that will be dangerous to their aircraft operations and in weather conditions—such as winds and temperatures—that affect the efficiency of their flights. The users of the weather products therefore attempt to interpret meteorological data to find where hazards and favorable conditions exist. In addition, users typically need to access several different weather products and mentally integrate the information from them in order to develop a complete picture. 
         [0008]    One common weather product is referred to as a Collaborative Convective-weather Forecast Product (“CCFP”). These forecasts often contain highly subjective values such as “confidence.” Such qualitative values are difficult to use as inputs for other tools. Such forecasts are often presented in large time increments, often in hours. The reason for the large time increment is the amount of automated and manual data processing that is required for the generation of the forecasts. The user receives many weather products, and these products are often not in agreement and are not for the actual time in which the user is interested. The user of these products therefore needs to have some meteorological knowledge to judge which of the products to believe, to interpolate between the times of effectiveness of the products, and then to generate an assessment of the level of probability of hazards implied by the weather forecast. 
         [0009]    The further into the future the prediction is carried, the less certainty there is that the forecasts will be correct. This is especially true of convective weather forecasting. Convective weather is the source of turbulence, hail and lightning, all of which are hazards to aviation. The certainty of the forecast is normally expressed as a “probability” of the forecast weather occurring. With the convective weather forecasting example, this is stated in terms of “radar cloud tops,” and “likely percentage coverage of a several thousand square mile area” reader will note that the CCFP does not express probabilities of the hazards such as turbulence in objectively quantifiable terms specific to turbulence. Even when turbulence is forecast by some products it is in subjective values such as “moderate.” Of course, turbulence that is moderate for a large aircraft may be severe for a small one. 
         [0010]    Users who are planning flights are required to identify hazards to the flight and attempt to quantify them and their affect on their aircraft. However, the user is presented with conflicting views of weather from the various data sources. The large time between forecast updates is also a problem, since a first available forecast may be for a point in time one hour before the flight passes a point and the next forecast an hour after the flight has passed. 
         [0011]      FIGS. 1 and 2  illustrate the problem of using historical weather data.  FIG. 1  shows weather data for the continental United States at the flight planning stage. Aircraft  16  is to fly from Los Angeles, Calif. (denoted as origin  12 ) to Atlanta, Ga. (denoted as destination  14 ) along planned route  10 . The dispatcher typically evaluates the route approximately 1 hour before takeoff. The weather data may be 30 minutes old when the dispatcher evaluates the route. The weather data of  FIG. 1  illustrates a moving storm front  18  with associated storm cells. Storm front  18  intersects a portion of planned route  10  at the time the weather was observed. 
         [0012]    As shown in  FIG. 2 , by the time aircraft  16  is within 2 hours of destination  14 , storm front  18  has moved beyond destination  14 . In this example, the dispatcher may have correctly predicted that planned route  10  would avoid storm front  18 . 
         [0013]    In the example illustrated in  FIGS. 1 and 2 , the dispatcher used radar data as proxies for hazardous weather conditions. Weather data is not always a reliable proxy for predicting a hazardous condition. Radar returns generally show raindrop density. As illustrated in  FIG. 3 , a radar return illustrates the presence of storm cell  20  and storm cell  22 . Regions  30  denote areas of heaviest rain. Regions  28 ,  26 , and  24  illustrate heavy rain, moderate rain, and light rain respectively. An inexperienced dispatcher viewing weather data as proxies for hazardous conditions might look at such a radar return and determine that flying between storm cell  20  and storm cell  22  would be the safest route. Severe turbulence zone  34  actually exists between storm cell  20  and  22 —an area the proxy data suggests should be free and clear of hazardous conditions. In addition, hail can be blown well clear of the hazard area indicated by the proxy as illustrated by potential hail zones  32 . 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    The present invention comprises a new method and system for generating probabilities of objective values of hazards as a fine granularity grid in four dimensions (three spatial dimensions plus time) to be used by decision support and visualization tools. Utilizing the proposed system, weather data received at different times and in different formats may be used as input data to create a fine four-dimensional grid of intelligent software agents. The method allows for proxies and/or subjective information on hazards that may arrive asynchronously and with poor temporal and spatial accuracy to be converted into a standard four-dimensional hazard probability grid. The grid is created automatically, without the need for expert human interpretation. 
         [0015]    The data assimilation and conversion is performed by intelligent software agents. These agents convert the input data into hazard probabilities at one or more four dimensional points. These points are represented as nodes in a four dimensional matrix. Each node communicates its current hazard probabilities to its neighbors in space and time. The neighboring nodes ensure that the probability gradient and probability density functions follow the correct rules for the hazard type in the current or future environment. The result is that information on a proxy for a hazard is translated into a hazard probability of an objective value of the hazard at a point on the four dimensional grid. The probability values for that hazard objective value for all the neighboring points then change to represent the correct probability gradient. 
         [0016]    This approach integrates the input information and the users decision support tools so that the user may easily search the four-dimensional grid for four dimensional ‘volumes’ of high probability of hazards and choose the least-risk path through the four-dimensional matrix. The grid is updated with each asynchronous observation or forecast product input and generates the hazard probability grid at regular and frequent intervals. The hazard probability grid can be used to provide visualizations of the hazard levels for display to the users. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0017]      FIG. 1  is a graphical depiction of a planned route and historical weather data. 
           [0018]      FIG. 2  is a graphical depiction of a planned route and historical weather data. 
           [0019]      FIG. 3  is a graphical depiction of a radar return. 
           [0020]      FIG. 4  is an illustration of a three-dimensional grid of software agents. 
           [0021]      FIG. 5  is a detail view of a three-dimensional grid of software agents. 
           [0022]      FIG. 6  is an illustration of a simplified two-dimensional grid for determining the probability of rainfall. 
           [0023]      FIG. 7  is an illustration of a portion of a grid representing a geographic region adjacent to a mountain. 
           [0024]      FIG. 8  is a graphical display, illustrating a volumetric representation of a weather hazard. 
           [0025]      FIG. 9  is a two-dimensional risk projection for a jetliner and a general aviation aircraft. 
           [0026]      FIG. 10  is a three-dimensional representation of terrain and probabilistic weather hazards. 
           [0027]      FIG. 11  is a three-dimensional representation of terrain and probabilistic weather hazards. 
           [0028]      FIG. 12  is a three-dimensional representation of probabilistic hazards and an aircraft route avoiding the hazards. 
           [0029]      FIG. 13  is a three-dimensional representation of probabilistic hazards and an aircraft route avoiding the hazards. 
           [0030]      FIG. 14  is an illustration of the effect of terrain on a radar coverage zone. 
           [0031]      FIG. 15  is an illustration of how terrain may be used to avoid radar detection. 
           [0032]      FIG. 16  is an illustration of how terrain may be used to avoid radar detection. 
           [0033]      FIG. 17  is a section view, showing the internal details of a volumetric representation of a probabilistic weather hazard. 
           [0034]      FIG. 18  is an illustration of a container ship encountering waves and wind. 
           [0035]      FIG. 19  is a graphical display, showing two-dimensional representations of probabilistic hazards and a route to be followed by a container ship to avoid the hazards. 
           [0036]      FIG. 20  is a diagram, illustrating the input of data into a four-dimensional grid. 
           [0037]      FIG. 21  is diagram, illustrating the regular export of the probability values from the four dimensional grid to a data store. 
           [0038]      FIG. 22  is a diagram, illustrating the interface between decision support tool applications and a data store. 
           [0000]    
         
           
                 
               
                 
                 
                 
                 
               
             
                 
                     
                 
                 
                   REFERENCE NUMERALS IN THE DRAWINGS 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                   10 
                   planned route 
                   12 
                   origin 
                 
                 
                   14 
                   destination 
                   16 
                   aircraft 
                 
                 
                   18 
                   storm front 
                   20 
                   storm cell 
                 
                 
                   22 
                   storm cell 
                   24 
                   region 
                 
                 
                   26 
                   region 
                   28 
                   region 
                 
                 
                   30 
                   region 
                   32 
                   potential hail zone 
                 
                 
                   34 
                   severe turbulence zone 
                   38 
                   grid 
                 
                 
                   40 
                   node 
                   42 
                   local peak 
                 
                 
                   44 
                   altitude 
                   46 
                   jetliner 
                 
                 
                   48 
                   general aviation aircraft 
                   50 
                   risk exceedance zone 
                 
                 
                   52 
                   terrain hazard 
                   54 
                   weather hazard 
                 
                 
                   56 
                   combined hazard 
                   58 
                   traffic hazard 
                 
                 
                   60 
                   terrain hazard 
                   62 
                   risk aversion scale 
                 
                 
                   64 
                   instantaneous risk aversion 
                   66 
                   radar installation 
                 
                 
                   68 
                   radar coverage zone 
                   70 
                   terrain 
                 
                 
                   72 
                   altitude AGL 
                   74 
                   icing hazard 
                 
                 
                   76 
                   turbulence hazard 
                   78 
                   container ship 
                 
                 
                   80 
                   wave crest 
                   82 
                   land 
                 
                 
                   84 
                   wave/wind hazard 
                   86 
                   shallow hazard 
                 
                 
                   88 
                   observed/reported information 
                   90 
                   conversion software 
                 
                 
                   92 
                   grid 
                   94 
                   export process 
                 
                 
                   96 
                   data store of hazard values 
                   98 
                   application program 
                 
                 
                     
                     
                     
                   interface 
                 
                 
                   100 
                   DST applications 
                   102 
                   low visibility hazard 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]      FIGS. 20-22  show an overview of a process for generating a four-dimensional hazard probability grid for predicting locations of hazardous conditions and providing hazard probability data to a user in a useful form.  FIG. 20  shows a schematic depiction of a grid, with individual points or nodes in the grid being shown as ovals. The process generally involves assembling forecast and observed/reported information  88  and manipulating these input data using conversion software  90  to create probabilities of objective values of hazards as an input into the fine granularity, four-dimensional probabilistic agent grid  92 . Observed/reported information  88  may include information from observations and predictions arriving asynchronously for any time period and any three-dimensional position in the grid of hazard data. Observed/reported information  88  is usually reported in large time and spatial increments. As an example, observed weather information is often reported in hourly increments for controlled airports with forecasts every six hours. The present invention manipulates these data and presents them in a fine spatial and temporal grid which is a more readily usable format for the Decision Support Tools. 
         [0040]      FIG. 21  shows how the hazard grid data is exported for use in decision support tools. Grid  92  is a simple four dimensional data array of hazard objective values and associated probabilities. The grid is regularly updated and the values stored in the grid are then exported to data store of hazard values  96  via export process  94 . This four-dimensional hazard data is maintained in data store of hazard values  96  so that the hazard may be further transmitted to the recipients&#39; decision support tool (“DST”) applications as will be described in greater detail subsequently. 
         [0041]    There are many applications for which four-dimensional representations of hazards are useful. For example, it may be used to forecast probabilities of hostile troop movements or certain types of weapon systems. The decision support tools may incorporate this forecast information to identify the type of approach which is most likely to avoid engagement or detection. It may also be used to forecast the effect of a hazardous material explosion on an area. The decision support tools may be configured to forecast areas that would be safe for emergency response teams from building debris and nuclear/biological/chemical results of the explosion. Many other applications are possible, but for greater clarity the description will first focus on the implementation of four-dimensional representations of aviation hazards for use in decision support tools. 
         [0042]    As mentioned previously, the process has as its input any or all normal forecast and observed/reported information  88 . This information may already be “gridded” but typically at large temporal and spatial intervals (such as with the Rapid Update Cycle weather model). The information may be graphical and textual, showing a probability of an event or proxy event in the future (such as forecast radar echo tops and forecast composite reflectivity in a CCFP). This information requires translation into the probability of one or more hazards for which they are a proxy. This translation is performed by conversion software  90 . For example, high radar echo tops and high radar reflectivity are used as proxies for the presence of turbulence, hail and lightning. 
         [0043]    Observed/reported information  88  may also be in the form of specific reports of a hazard, such as a pilot reporting severe clear air turbulence. Accordingly, the imported data may include data of the following types: 
         [0044]    1. textual reports of actual hazard occurrences and their subjective or objective values; 
         [0045]    2. numerical reported data for a small area; 
         [0046]    3. gridded data that covers all or a subset of the grid but at a coarser spatial and temporal resolution (These values may need to be converted to hazard probabilities and interpolated to the grid points); and 
         [0047]    4. graphical data that requires interpretation, such as a probability boundary (This could be the CCFP warnings) or a Significant Meteorological (SIGMET) Advisory in aviation terms; or even a synoptic forecast chart. 
         [0048]    As shown in  FIG. 20 , conversion software  90  reads each observation or forecast information type and converts the information into four-dimensional probabilities of objective hazard values (three spatial dimensions plus time). In doing so, conversion software  90  identifies the time and place of these probabilities. As an example, a report on existing conditions at a point will have a probability of 1 (100%) whereas a forecast of the same conditions at that point but several hours into the future may have a maximum probability of 0.6 (60%) due to the known inaccuracy of forecasting that hazard. 
         [0049]    Accordingly, conversion software  90  is concerned with the conversion of: 
         [0050]    1. deterministic values to probabilistic values; 
         [0051]    2. subjective values to objective values; and 
         [0052]    3. graphically displayed proxies for the values of concern and proxy forecasts to the four dimensional probabilities of objective values of hazard. 
         [0053]      FIG. 20  shows the asynchronous input information as observed/reported information  88 . Conversion software  90  converts this information and input these values to the agent(s) in the correct four-dimensional position in four-dimensional probabilistic agent grid  92 . The agents in the grid represent a particular three-dimensional point in space at a particular instant in time. The values at that point are updated for each step into the future. The point in space represented by the agent will have influences from the geography around that point. This geographical factor can be held as a set of rules for how particular hazards affect that point in space. For example, in the aviation case, a point in space that is just downwind of a mountain may always set a probability of turbulence based on the wind direction and speed, even without an external input. In addition, a point in space that is inside a mountain would have a probability of 1 (100%) of hazard to aviation all the time. 
         [0054]      FIG. 4  illustrates a small number of intelligent agent nodes on the four-dimensional grid, with an indication of the communication of probability and state changes between the nodes. The actual grid would consist of a three-dimensional grid of intelligent software agents (or “nodes”) representing the entire volume of airspace. The fourth dimension of time would be included by creating a set of three-dimensional grids for each time period out to the future time limit of forecasting. In the example shown in  FIG. 4 , grid  38  is a three-dimensional grid with nodes  40  corresponding to locations in three-dimensional space separated by five nautical miles in a North/South/East/West grid and one thousand feet in altitude. There may then be a three dimensional grid for each 15 minutes from 15 minutes in the past out to 12 hours in the future. Other granularities for time and space may also be used. 
         [0055]    Parameters are defined for each node  40  on grid  38 . Rules are also defined to govern the interaction of each node with neighboring nodes. These “rules” are preferably modifiable, so that the grid can “learn” as it accumulates data over time. The term “neighboring node” generally refers to a node that is adjacent to the reference node on the three dimensional grid. In the present example, a neighboring node is a node corresponding to a location in space that is approximately 5 miles from to the point in space corresponding to the reference node. 
         [0056]    Multiple existing predictive models can be fed into each node. In the weather hazard example, these would be weather forecasting models. These weather forecasting models may be updated every 15 minutes or when new data is input into grid  38 . For example, the grid may be updated when a pilot observes and reports turbulence or icing at a location or wind gusts are observed on the ground. 
         [0057]      FIG. 5  shows a detailed view of a portion of grid  38 . As mentioned previously, each node  40  in grid  38  represents a point in space and time. Each node has a set of parameters. Each link between adjoining nodes includes a set of rules describing how the neighboring node relates to the reference node and vice versa. It is preferably that some of the parameters to be stated in terms of the probability of a condition existing at the point in space represented by the node. For example, while pressure and temperature may be actual fixed values, actual hazards such as precipitation, icing conditions, and turbulence can be given as probabilities. When node  40  receives a probability of an objective value and possibly a probability skew definition, either from a neighboring agent or from an input agent, the agent uses the rules to first set the probability of that objective value at the point it represents and then send a probability of an objective value and the probability skew if necessary to its neighbors in time and space. Those that are skilled in the art will appreciate that the computer implementation of this logic may differ in order to achieve a greater processing efficiency. 
         [0058]      FIG. 6  is a very simple two-dimensional grid example showing how a probability of a condition “ripples through” the grid. At time t 1 , rain is observed at the location corresponding to node N 1 . The fact that it is actually raining at node N 1  increases the probability of rain at nodes proximate to N 1  including nodes N 2 , N 3 , and N 4 . The probability of rain at each node at time t 1  is illustrated by the bar graphs above each node. At time t 2 , the probability values for precipitation change at N 1 , N 2 , N 3 , and N 4  in accordance with the rules prescribed by the weather forecast models embedded in each node  40 . 
         [0059]    The concept of nodes  40  passing probabilities of objective hazard values and skews between each other may be modeled as a Petri-Net which consists of “places,” transitions, and arcs that connect them. The places pass values and transitions between them, and in the present example, the places represent actual three-dimensional positions at a particular time. If a Petri-Net model is used, each node  40  represents a single intelligent node or agent at a four-dimensional position on the grid. It receives change of state input(s) from another node that first received information. Each node  40 , when given the probability of an objective hazard value, pass their new values to their neighboring agents in space and time via continuous/logical change of states. 
         [0060]    As time passes, the intelligent agents representing the nodes in the four-dimensional grid and their associated hazard data move into the past. The intelligent nodes can then compare their hazard values with the actual values and the values that were forecasted. The intelligent nodes then construct the new intelligent agents in the future for their three-dimensional position and include, if necessary, corrective parameters for future input values from forecasts and inputs from particular input agents. 
         [0061]      FIG. 7  illustrates how the “rules” governing the behavior of nodes may be updated over time to “learn” from observed trends. Local peak  42  corresponds to a mountain peak. Actual reports for that position may establish the fact that with particular wind directions, there is always a level of turbulence. A west wind will tend to produce turbulence proximate the nodes that are downwind of local peak  42 . Thus, when a west wind is observed, a higher probability of turbulence would be predicted at nodes N 2 , N 3 , and N 8 . There are more complex formulae that are used in meteorology that could be applied to inputs from particular types of forecasts and ensemble forecasts. 
         [0062]    Various algorithms may be employed to implement such “corrections” to the embedded models. In one example, the actual values of the hazards at the present time are returned to the intelligent agents that had made forecast inputs to the grid. These values will allow the input agents to correct their Bayesian trust levels in the probabilities that are generated. 
         [0063]    Referring back to  FIG. 21 , on a periodic basis, or when a particular threshold value is passed, four-dimensional probabilistic agent grid  92  exports the probabilities of objective hazard values into data store of hazard values  96 . This database holds the four-dimensional grid of the probability of objective hazard values. The database is said to store the information in fine granularity. “Fine granularity” means that the spatial and temporal resolution of the information must be suitable for the user&#39;s applications and decision support tools. In the aviation meteorological hazard example, the decision support tools would preferably utilize hazard probability data with time increments of no more than 15 minutes and spatial increments of 5 miles latitude and longitude and one thousand feet altitude. 
         [0064]    A different resolution may be better suited to a non-aviation application. If a nautical system were used as an example, the granularity in miles may be ten nautical miles with the vertical dimensions being in ten feet increments limited to an altitude up to 500 feet above the sea surface and temporal granularity of thirty minutes. Also, other hazards may be required such as wave height. 
         [0065]    As illustrated in  FIG. 21  and described previously, grid  92 , which contains the calculated values of objective hazard value probabilities, is exported to data store of hazard values  96 . The data may then be accessed for use by decision support tools.  FIG. 22  schematically depicts this data extraction. Decision support tool applications  100 , which may include simple visualization tools, may access the data store of hazard values  96  via application program interface  98 . The data interface describes the format of the data and the subscription method to be used. As the quantity of data will be large, decision support tool applications  100  may be configured to subscribe to a small segment of the data from the data base that covers their areas of interest (such as a limited geographic region). 
         [0066]    Accordingly, application program interface  98  includes a subscription mechanism to allow decision support tool applications  100  to interface with the data store. The subscription mechanism can be further configured to allow the decision support tools to receive automatic updates of information, to limit the amount of the information that they require, or to limit the type of hazard that they require. Decision support tool applications  100  may be further configured to find the least hazardous route through the area of the real world represented by the four-dimensional grid of data. This functionality will be described in greater detail subsequently. 
         [0067]      FIG. 8  is a graphical depiction of a weather hazard, storm cell  20 , occupying a three-dimensional space at a designated time. Storm cell  20  has tops at 28,000 feet. Storm cell  20  would appear as a substantial hazard on a conventional weather plot (where radar returns are used as a proxy for a hazard). However, since transcontinental jetliner  46  is flying at 38,000 feet, storm cell  20  does not pose a hazard to it. On the other hand, general aviation aircraft  48  has a service ceiling of 12,000 feet. Thus, general aviation aircraft  48  should attempt to avoid the hazard posed by storm cell  20 . 
         [0068]      FIG. 9  illustrates vehicle-specific, two-dimensional risk projections of the hazard shown in  FIG. 8 . In the risk projection for jetliner  46 , no hazard appears since storm cell  20  is well beneath the cruising altitude of jetliner  46 . The two-dimensional risk projection for general aviation aircraft  48  reveals the hazard as risk exceedance zone  50 . This depiction reveals to the pilot or dispatcher that the trajectory of general aviation aircraft  48  should be altered to avoid the hazard. 
         [0069]      FIGS. 10 and 11  illustrate how multiple hazards may be combined into a single, integrated display. The left view in  FIG. 10  shows terrain hazards  52  as a function of altitude  44 . Terrain hazards  52  may be mountain peaks, skyscrapers, or other ground-based hazards. The right view in  FIG. 10  shows weather hazards  54  as a function of altitude  44 . Weather hazards  54  reveal areas where there is a high probability of turbulence, hail, or lightening.  FIG. 11  shows the combination of weather and terrain hazards as combined hazard  56 . These are four-dimensional plots which show increasing risk the further one travels into the hazard zone. The reader will note that in  FIG. 11 , combined hazard plots  56  are shown relative to risk aversion scale  62 . In most cases, risk aversion scale  62  correlates with altitude. The concept of navigating through such terrain is familiar to aviation personnel and the decision support tools may utilize common algorithms for terrain following. The area/time described can be considered as a topographical probability density surface. The trajectory should fly a safe separation “above” the probability values. The safe separation is a function of the physical safety and the risk aversion of the users. Using such a display, an avoidance path may be chosen which avoids high hazard probabilities by a defined risk aversion factor. 
         [0070]    Although risk aversion scale  62  most often correlates with altitude, this is not always the case. For example, the most common avoidance to icing conditions is to descend to a lower altitude. “Icing” refers to a phenomenon when an aircraft&#39;s wing begins to accumulate ice. The accumulated ice both adds weight to aircraft and changes the shape of the airfoil. If the airfoil accumulates enough ice, the aircraft may stall. 
         [0071]    In an actual display, the display of combined hazard may be modified from  FIG. 11  to show combined hazard  56  as a function of altitude (instead of risk aversion scale  62 ). In such a display, combined hazard  56  may appear as hazard of varying intensity (e.g., depicted by different shades of color). In one example, terrain hazards may appear in bright red since it would never be acceptable to fly through terrain. Precipitation or light turbulence, however, might not be a significant hazard to a particular aircraft or pilot. Less significant hazards and areas where hazard probability is low may be illustrated in lighter shades or alternate colors. This feature allows a pilot to consider his or her personal risk tolerance when evaluating whether to penetrate a hazard region or avoid the region altogether. For example, a corporate pilot may be willing to fly through significant weather hazards to pick up the company&#39;s CEO on time, but may prefer to alter the return route to provide a smooth route when the pilot&#39;s boss is on board. 
         [0072]      FIGS. 12 and 13  shows a graphical depiction in which the hazard probabilities are visually presented as volumes of space.  FIGS. 12 and 13  illustrate the same aircraft trajectory, planned route  10 , from different perspectives. Several hazards are illustrated in the display including, terrain hazards  60 , traffic hazard  58 , and weather hazards  54 . Planned route  10  is marked with time intervals to indicate the approximate time the aircraft will pass through the point in space if planned route  10  is followed. Traffic hazards  58  indicate areas where there is a high probability of aircraft traffic around the airport. Traffic hazards  58  correspond to the approach and departure vectors for the airport. These hazards get “taller” and more “diffuse” further from the airport. Weather hazards  54  are shown in the distance. These volumes represent anticipated weather at these locations several hours in the future. Future weather hazards may appear larger and less distinct, because of increasing uncertainty as one looks forward in time. Terrain hazards  60  remain static over time.  FIG. 13  better illustrates the relationship of risk aversion scale  62 . The vertical lines under planned route  10  illustrate the instantaneous risk aversion  64  of the aircraft at a series of points along the aircraft&#39;s trajectory. 
         [0073]    Those skilled in the art will realize that the graphical depiction of weather hazards  54  in  FIGS. 12 and 13  are based on certain assumptions of time—namely that the aircraft follows the planned route at the planned time and speed. In order to create the avoidance path, the aircraft&#39;s performance must be known and considered. If the aircraft slows down or enters a circular hold at some point rather than continuing along its projected path, the hazard probability “mountains” will change and a new avoidance path may need to be determined. 
         [0074]      FIGS. 14-16  illustrate how the present invention can be used in military applications to assist military aircraft avoid radar detection.  FIG. 14  illustrates radar coverage zone  68  for ground radar installation  66 . Radar coverage zone  68  is limited by terrain  70  and altitude.  FIG. 15  shows how a military aircraft can fly a route (planned route  10 ) using terrain  70  to make its way between two radar installations  66 .  FIG. 16  shows how the display can be used to plan an appropriate route. In this illustration, altitude above ground level (“AGL”)  72  is illustrated by vertical lines beneath planned route  10 . Altitude AGL  72  indicates the successive altitudes attained by an aircraft flying along planned route  10 . Of course, weather hazards may also be added to the display. The pilot or planner may then use vehicle-specific or mission-specific parameters to control the display. As an example, if the radar sites control known surface-to-air missiles (SAMs), the pilot or planner might be willing to risk severe weather to avoid radar detection. 
         [0075]      FIG. 17  is illustrates a “layered” hazard display. The hazards have been cut (a single planar slice) in this view to show to show the internal details of the hazard. Terrain  70  has no internal details since flying through part of terrain  70  is never acceptable. The weather hazards, however, have internal details. It is preferable that these internal details be indicated by varying color or labeling.  FIG. 17  shows general aviation aircraft  48  approaching a weather hazard along planned route  10 . Low visibility hazard  102  indicates a risk of clouds and light rain. The aircraft can fly through these conditions, but icing hazard  74  and turbulence hazard  76  pose significant risk to general aviation aircraft  48 . Even if the aircraft can safely fly through low visibility hazard, it is possible that the pilot is not trained for flying in such conditions. A non-instrument rated pilot can only legally fly through VFR (visual flight rule) conditions. Significant areas of low visibility are known as IMC (instrument mandated conditions). Thus, if the subscribing pilot is a non-instrument rated pilot, the whole hazard would not have any interior features and the pilot would be informed that he must avoid the weather hazard altogether. If, on the other hand, the pilot is instrument rated, the display would show a safe route through the weather hazard. 
         [0076]    The decision support tool applications may be further configured to evaluate planned routes and suggest alternate routes where the planned route is likely to encounter a hazard which exceeds the operator&#39;s risk aversion for the hazard. In order to do this, the decision support tools require as inputs (1) the objective hazards that the vehicle must avoid to be safe, and (2) the probability of those hazards that the operator of the vehicle can accept or not accept. The operator may add a value of avoidance for particular probabilities that defines that operator&#39;s risk aversion for that hazard. So if the operator selects a trajectory and there is a probability of 70% at a point for a hazard for which the operator has stated a 50% “clearance” is needed (i.e. a maximum of 50% probability of that hazard can be accepted), the decision support tool may indicate that the trajectory is unsafe and/or may recalculate a different route with lower probability of hazard. Sometimes this change may be a delay in departure which maintains the original three-dimensional trajectory if the delay causes the probability of hazard to drop to within an acceptable range. 
         [0077]    To identify an acceptable trajectory through the four-dimensional grid of hazard probabilities, the decision support tools define the initially proposed trajectory through that grid in four dimensions. The decision support tool can be configured to “know” the maneuvering capability of the aircraft in climb, descent and turn, and may investigate hazard probabilities that are above, below, left and right of each point on the trajectory and which can be reached in a period of time. The probabilities of hazards around the trajectory may be considered and the decision support tool may define a trajectory that attempts to remain in the ideal “probabilistic values.” If the trajectory cannot remain within the parameters defined by the user, then the trajectory cannot continue in a particular direction and will need to be re-routed earlier to avoid the hazards. 
         [0078]    It is preferable that the representations of hazards displayed on decision support tools be vehicle-specific.  FIGS. 18 and 19  illustrate an example of a hazard display for container ships. This particular example considers hazards that might affect container ship  78 . In  FIG. 18 , waves, identified as wave crests  80 , are approaching container ship  78  from the North-Northwest while the wind is approaching from the North-Northeast. Container ship  78  has specific characteristics (including length, width, center of gravity, rolling characteristics) which make it vulnerable to certain wind and wave combinations. It should be noted that some conditions which are safe for a large ship may pose a greater danger to a smaller ship, and vice versa. For example, certain long ships (such as container ship  78 ) are more vulnerable to waves having a long crest-to-crest distance than shorter ships. 
         [0079]      FIG. 19  shows a two-dimensional hazard plot for the container ship example. Because a watercraft cannot alter its altitude like an aircraft, a two-dimensional display is sufficient to show the hazards relevant to the watercraft. The watercraft operator is only concerned with hazards that may exist around sea level. As shown in  FIG. 19 , land  82  and shallow hazard  86  indicate terrain hazards. These terrain hazards are generally static except to the extent that the tide level influences the shape of shallow hazard  86 . Wave/wind hazard  84  is much more dynamic. As shown in  FIG. 19 , the planner is able to use the display to determine planned route  10  for container ship  78  which avoids potential hazards that are of concern to container ship  78 . If conditions change differently than anticipated, the route may be altered to avoid the projected location of the hazards. 
         [0080]    Referring back to  FIG. 22 , decision makers using DST applications  100  obtain data for the hazard displays via application program interface  98 . The amount and type of data transmitted to DST applications  100  can vary based on (1) the resources available to DST application  100 , (2) the nature of the hazards of concern to the decision maker, and (3) the level of decision autonomy desired by the decision maker. On one extreme, an inexperienced pilot may simply want a display of potential hazards that are in the general vicinity of his planned route. In this example, the inexperience pilot visualization application may require the hazard data to be pre-processed to the level of an image or video feed. This particular pilot and aircraft may therefore have one type of subscription in which only processed image data is transmitted to the visualization tool. 
         [0081]    On the other extreme, a military aircraft may want hazard data that includes specific hazard parameters or risk models. The DST application used by the military decision maker may be capable of processing the hazard parameters and risk models to optimize routes and generate displays based on the risk models and parameters. In the military context it may be preferable for the determination of hazards and evaluation of routes be performed independently by the decision maker&#39;s DST. The military aircraft would therefore utilize a different type of subscription than the inexperienced pilot of the previous example. 
         [0082]    It is further contemplated that the transmission of hazard data be updated continuously, at designated time intervals, or when new input data is received by the grid. Also, new data may be transmitted when the vehicle deviates from its originally planned trajectory. For example, if an aircraft does not depart at the planned time, new hazard data may be acquired to update the display. Thus, the timing of data transmissions may be varied as required as needed for the particular application. 
         [0083]    Referring back to  FIG. 20 , conversion software  90  is used to convert observed/reported information  88  into data that can be input into grid  92 . Observed/reported information  88  includes many currently available weather products. Thus, conversion software  90  employs processing algorithms which are capable of converting data from existing weather products into deterministic values which can be fed to grid  92 . These processing algorithms will vary depending on the particular weather product that is used. For example, radar returns detailing raindrop density for a particular geographic region may be fed directly to conversion software  90 . Conversion software  90  then can correlate the raindrop density data to specific nodes on grid  92  at the time of the radar return. Drop density values may then be applied directly to grid  92  as a parameter. Alternatively, drop density data may be pre-processed using known meteorological models to compute other hazard parameters to be fed into grid  92 . 
         [0084]    Although the preceding descriptions contain significant detail, they should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As an example, although the description details how probabilistic forecasting can be used for weather hazards, the same principles can be applied to other aviation hazards such as SAM (Surface to air missile) sites in a combat environment and to hazard prediction in non-aviation related industries such as frost or heavy rain affecting the construction industry. Accordingly, the scope of the present invention should be defined by the claims and not the examples given.