Overview (Introduction and Components)

Page Contents

1. ISC Functionality
2. ISC Grids
   1. Virtual ISC Grids
3. ISC Request
4. ISC Routing Table
5. ISC Edit Areas
6. ISC Utilities
7. iscSendSampleDef
8. ISC Mode

ISC Functionality

Intersite Coordination (ISC) works using the following steps:

1. Sites register with the ISC Routing Table (IRT) to send and receive grids.
2. When sites save grids, the ISC process checks with the IRT to see which grids are being requested.
3. The ISC process then uses the ifpnetCDF script to create the appropriate netCDF file bundling and sending only the requested data to each site.
4. The receiving site uses the iscMosaic script to get the netCDF file opened and processed into GFE.

ISC Grids

ISC grids provide a mechanism for your office to compare grids with those from neighboring offices. Grids are mosaicked with other ISC grids and stored in the ISC database. The ISC grids show you what your neighboring offices are forecasting in comparison to your own forecast. They are snapshots of an office's forecast grids, sent to other offices via the AWIPS network.

The processing of ISC grids is handled by the iscMosaic script (will be discussed more in the Command Line Scripts Section) which is located in the /awips2/GFESuite/bin directory. Once ISC grids are received, iscMosaic processes them one site at a time, at the native temporal resolution. ISC grids are created using the highest temporal resolution received. Grid points not assigned any data are set to the minimum value for that element. The composite ISC grids created by the iscMosiac script are placed in the ISC database. The history for ISC grids is retained and can be accessed by right clicking over an ISC grid in the Grid Manager and selecting Display Info. This will display the age of the grid, how the grid was populated/created, what guidance was used in the grid, and the GFE user who created the grid.

Virtual ISC Grids

There may be more than one ISC grid for one of your Fcst grids. This is one reason why virtual ISC grids were implemented. These grids were also implemented to help collaboration between offices using different grid durations and start times. They are available for MaxT, MinT, PoP, QPF, and SnowAmt. The example below shows how the PoP, MaxT, and MinT virtual ISC grids work:

• Site A creates a PoP grid from 12Z-18Z while neighboring Site B creates two 3-hour PoP grids over this period (12Z-15Z and 15Z-18Z).
• The virtual ISC PoP grids show Site A the max value of its neighboring offices from 12Z-18Z. It combines the grids from Site B, takes the max value for each point, and displays the value to Site A.
• Since there is only one grid from Site A, the virtual ISC grid functionality is not needed for site B. Site B simply sees the 6-hour PoP grid from Site A.
• If Site A wants to see the actual grids from Site B rather than the virtual ISC grid, it can split its 6-hour grid into 3-hour grids like Site B.

Virtual ISC grids for accumulating grids i.e., QPF and Snow Amt, behave differently:

• Site A creates a QPF grid from 12Z-18Z while neighboring Site B creates two 3-hour QPF grids over this period (12Z-15Z and 15Z-18Z).
• The virtual ISC QPF grids show Site A the cumulative QPF value of Site B from 12Z-18Z. It combines the two grids from Site B and displays the total value for each grid point to Site A.
• The virtual ISC QPF grids show Site B half of the six-hour QPF value from Site A for each three-hour grid, since Site B's three-hour grid is half as long as Site A's six-hour grid. If Site B's grids were two hours long, Site B would see one-third of Site A's total for each two-hour grid, etc.
• If Site A wants to see the actual grids from Site B rather than the virtual ISC grid, it can split its six-hour grid into two three-hour grids like Site B.

While virtual ISC grids can be helpful, they can also make finding discrepancies harder and can lead to collaboration problems.

ISC Request

The ISC Request/Reply GUI requests ISC grids from neighboring offices. It is accessed via the Consistency menu in GFE. The GUI has three columns Domain, Grid Source, and Weather Elements. The Domain column shows all of the sites from which you can request ISC grids. This column is determined by the REQUESTED_ISC_SITES list (discussed more in the ISC Configuration Section). The Grid Source column is dependent on which sites are selected in the domain column. It shows which grids can be requested from the site's dv3 (EDEX cluster). The Weather Elements column shows all of the weather elements for which you can request ISC grids. It is determined by the REQUESTED_ISC_PARMS list (discussed more in the ISC Configuration Section). Using this GUI to request ISC grids has a significant effect on the system performance at your site and the sites from which you requested ISC grids. Use this GUI only when absolutely necessary. After making the request, receiving all ISC grids may take some time. Do not click Make Request more than once. Multiple instances of the process could cause major slowdowns on your system and the other offices' system. ISC request is usually only used after an extended outage (e.g., after your system has been restored to normal operations after being backed up by one of your service backup offices).

ISC Routing Table

ISC grid routing occurs automatically through a server known as the ISC Routing Table (IRT). A site configures what data it wants to receive and then registers with the IRT with its site ID. When ISC data is sent, the IRT determines destinations based on the site configuration.

ISC Edit Areas

Three baseline edit areas in GFE pertain to ISC. All of these edit areas can be found under the Edit Areas menu under the ISC menu in GFE. These edit areas are the ISC_Tool_Area, ISC_Send_Area, and ISC_XXX edit areas where XXX is the site id. The ISC_Tool_Area edit area (shown below for BOU) is a band around the border of a WFO where the ISC discrepancy tools check for grid collaboration issues between your wfo and your neighbors. EDEX automatically generates this edit area, and updates for your grid domain definition when EDEX restarts.

The ISC_Send_Area edit area (shown below for BOU) contains the set of grid points sent to both the Center Server (for Service Backup and NDFD) and the IRT. Offices should have and need to have this edit area in order to send ISC grids successfully.

The ISC_XXX edit area, where XXX is the site id, shows an office's area of responsibility, including public, marine/nearshore and offshore/high seas zones. The ISC grids from surrounding offices are cropped to these edit areas so they should not overlap with your local area. Offices should also have this edit area defined for any offices from which they want to receive ISC grids.

ISC Utilities

The Show_ISC tool suite is a group of baseline Smart Tools which use a common utility, ISC_Utility for default settings. The Show_ISC tool suite contains Show_ISC_Area, Show_ISC_Grid, Show_ISC_Highlights, and Show_ISC_Info. The Show_ISC_highlights tool highlights grids that have a significant discrepancy with any of the ISC neighbors. The Show_ISC_Info tool creates a table of discrepancy information for each neighboring border. The Show_ISC_Area tool creates an edit area containing points in your CWA that when compared to a neighbor's ISC grids violate the discrepancy criteria for this parameter and point. The Show_ISC_Grid tool creates a discrepancy grid with the grid points inside your CWA set to the difference between it and its neighbor. The ISC_Utility.py file configuration section includes settings that may be overridden. The ISC_Utility_Local.py file contains overrides to the default settings. These two files are located in the Localization Perspective under the GFE Folder under the Utilities Folder as shown in the image below.

Make overrides to the ISC_Utility.py file in the ISC_Utility_Local.py file. This will require a SITE-level override of the ISC_Utility_Local.py file.

iscSendSampleDef

The iscSendSampleDef.py file is located in the Localization Perspective under the GFE Folder under the ISC Utilities Folder as shown in the image below.

The iscSendSampleDef.py file contains entries like the one shown below.

The first line defines the weather element which in this case is Td. The second line sets base times to 00Z and 12Z. This means it uses 00Z between 00Z-12Z and 12Z between 12Z-00Z. The next line specifies that starting at the nearest base time send hourly grids. The next line specifies that starting at 48 hours after the nearest base time stop sending hourly grids and begin sending grids every three hours. The final line specifies that starting at 84 hours after the nearest base time stop sending grids every three hours and begin sending grids every six hours.

The ifpnetCDF script (discussed in the Command Line Scripts Section) uses the iscSendSampleDef python script to filter weather element ISC grids and only send them for specific times. This can eliminate a great deal of ISC traffic. By default, all grids in the Fcst database, starting at 24 hours prior to the nearest 00Z through the end of the database, are eligible to be sent via ISC.

ISC Mode

ISC mode can be toggled on and off using the spider web button shown below.

When ISC mode is toggled on, the data presented in the spatial editor is the composite grid, rather than the forecast or primary grid. The composite grid is made up of the forecast grid over the CWA area, and all of the surrounding ISC grids received from adjacent WFOs for the remainder of the area. When in Show ISC Mode, the following behavior is changed from the default:

• A composite grid is shown in the spatial editor consisting of the forecast data over the combined CWA/Marine zones and ISC data over the remainder of the domain.
• Editing changes made to the forecast grid may not be visible, if those changes are made to the forecast grid outside of the CWA/marine zones.
• Blank areas indicate no data was received.
• The Pencil Tool will pick up the data from either the forecast data or the ISC data depending on the location of the start drag operation.
• The Move/Copy Tool will move/copy the composite grid and place it into the forecast grid.
  • The region copied/moved will be clipped to valid data points before the operation begins.
    • The valid data points are defined as your forecast grid and the valid ISC data.
• The Smooth Tool will smooth between the ISC and the forecast segments of the composite grid.
• The Color Bar Fit to Data calculations will use the composite grid.
• The Sample Tool and sample points will show the data value, the site identifier, the last update time, and whether or not the data came from an Official database for the ISC portions of the grid.
  • The site identifier, update time, and official database symbol may be turned off under the Maps menu under the Samples menu.
  • Markers (similar to samples except there are no data values displayed) may be placed at appropriate locations to indicate the site identifier, update time, and official database symbol.
    • These can be turned off under the Maps menu under the ISC Markers menu.
  • If the ISC data represents data from the official database, then a "P" symbol will be appended to the sample and marker strings.
  • If the ISC data represents data from any other database, e.g., the Fcst database then no symbol will be appended.
    • The purpose of the "P" symbol is to indicate that it is the official released forecast from that site.

The following items in GFE are not affected by toggling on Show ISC Mode:

• The temporal editor samples and edit operations always apply to the forecast data, and do not use the ISC portions of the grid.
• Queries apply to the forecast data, and do not use the ISC portions of the grid unless explicitly specified in the query.
• Most Smart Tools apply to the forecast data, and do not use the ISC portions of the grid in their calculations unless explicitly specified in the tool to use the ISC data set.
• The Contour Tool applies only to the forecast grid and does not use the ISC portions of the grid.