Set Meteorology Data An OMEGA simulation requires weather data to build initial conditions and boundary conditions. Common data sources are models whose domains are global or hemispheric, and whose forecast times are a few days. Observational data may also be used. Both surface and upper air observations may be used in an OMEGA run. When constructing an OMEGA simulation you must ensure that the met data you choose is valid for the time and space of your simulation. Not all models have global coverage and some model forecast times may not match your times. XOMEGA uses the concept of met segments to allow for maximum flexibility when specifying what meteorology to use. Essentially a met segment is a subdivision of the total time domain, coupled with the sources of data used for that time period. The met segments mechanism allows you to specify different sources of met data to be used for different times. As an example, consider modeling the weather for the city of Washington DC. You might want to produce a 3 day (72 hour) forecast for the DC Metro area. You will need to generate an initial condition for 00Z on the first day, and you will need to generate a sequence of boundary conditions for the entire length of your simulation. This city is within the domain of nearly all major atmospheric models, so gridded model data should be available for your domain. If you are interested in small scale effects, the you want to use the highest resolution data available to generate your boundary conditions. However, some high resolution models may not forecast for your total time so you won't be able to use the same model for all your boundary conditions. This is where met segments become very useful. You can define a series of met segments that specify which data sources to use for different periods of your forecast. You will be able to mix and match your met data to what is produced, maintaining the highest resolution possible. Assuming you have both a NWS feed and a FNMOC feed your forecast period may be split into these three segments: Segment 1 will cover the first 24 hour period and use ETAXP data. Segment 2 will cover the next 24 hour period and use NORAPSN data. Segment 3 will cover the last 24 hour period and use NOGAPS data. Using met segments gives you the flexibility to generate boundary conditions from different data sources at different times. This allows you to use the best data available used in your OMEGA simulation. The Set Meteorology dialog box is the control for defining met segments. The dialog has seven sections: Time Domain Display, Base Met Path Control, Met Data Server Controls, Sea Surface Temperature Control, Current Segment Controls, Segment Parameters, and Action Buttons. How to use each section will be described, followed by exact specifications of each control's actions, valid data range, and default value. Note that if the Temporal Domain data has not been filled the Set Meteorology dialog will not pop up. Instead an error message will pop up informing you of the error. When you acknowledge the error by clicking the "OK" button the Set Time Domain dialog will pop up. Temporal Domain Display This section of the dialog is a simple reminder of the Temporal Domain. It is presented so that you have the total time span of your simulation available as you define met segments. If the Temporal Domain is changed, the labels will be updated. Base Met Path Controls All OMEGA System met data sources are held under a common subdirectory called metdata/. This display and control allow you to change the location of this directory. Change Base Met Path - Clicking on this button will pop up a modified file selection dialog. Use the Filter Line, Directories and Files Lists to navigate among directories. Once you have found the desired location for the new Base Met Path, click on Change. Met Data Server Controls The Met Data Server (or MDS) is a system of interlinked data processing machines designed to supply data to remote sites that do not have any local met data processing. The MDS works on a simple request/fulfillment protocol with a few steps: the remote site puts a formatted request on the server's incoming directory; the server either fills the request from its own local data, or passes the request to another server to fill the request. A combination of FTP and JAVA RMI is used to transfer requests and data from any of several servers to the remote site. Data is generally transfered in compressed form. XOMEGA handles all the steps needed to use the MDS: request generation, FTP, and decompression. The controls in this section allow for choice of initial MDS machine, MDS account user name, and MDS user password. MDS IP Address or Name - This text entry box allows for the selection of which MDS machine to contact for data. Valid Input: any MDS machine name or IP address Default Value: 204.44.135.76 (DTRA HQ) MDS User - This text entry box holds the MDS account user name. Valid Input: any MDS account user name Default Value: user id that started the MDS process Note: If MDS is selected in any of the Met Segments, a dialog box will pop up requesting the password for the MDS account supplied. Sea Surface Temperature Control If your met data feed is set up to receive NOGAPS data from FNMOC, you may be able to use sea surface temperature (sst) data in your OMEGA simulation. Sea Surface Temperature - This simple toggle controls the use of sst data. If set to ON, sst data will be used. Valid Input: ON/OFF Default Value: OFF Current Segment Controls Initially the dialog will have only one segment defined spanning the entire time domain. The controls in this section are used to add, delete and cycle through all defined segments. Current Segment - A dynamic label showing the current segment and the total number of segments. The current segment will have its Segment Number Label non-shaded. All other Segment Numbers will be shaded. Left Arrow - Decrement the Current Segment. Cyclic action going down: 1 <- 2 <- 3 <- 4 <- 1 ... Right Arrow - Increment the Current Segment. Cyclic action going up: 1 -> 2 -> 3 -> 4 -> 1 ... Add - Add a segment to the end of the list. The text entry and option menus will be set to default values. It is the user's responsibility to adjust the Start Time and End Time entries to fit within the total time bounds of the simulation. Up to five met segments may be defined. Delete - Remove the Current Segment and shift up any subsequent Segments. For example: four segments are defined, the current segment is number 3, and Delete is clicked. Segment 3 is removed from the list, and Segment 4 becomes Segment 3. Segment Parameters Segment Number - Dynamic label used to highlight which segment is the current segment. The current segment will have its number in bold print. All other segments will have shaded grey numbers. Valid Range: 1 to 5, in fixed sequence Default Value: 1 Start Time - Start Time of Segment in full digit form: four digits for year, two digits for month, day and hour, single space between numbers. Valid Range: 1900 01 01 00 to 2100 12 31 23 Default Value: value copied from Start Time of Time Domain End Time - End Time of Segment in full digit form: four digits for year, two digits for month, day and hour, single space between numbers. Valid Range: 1900 01 01 00 to 2100 12 31 23 Default Value: value copied from End Time of Time Domain Gridded Weather Model - Source model to use for Segment. Valid Range: Installation dependent Default: Installation dependent Model Output Delta - This is a simple display that shows the time interval between forecast files of the selected gridded weather model. Number of BC Files - This is a simple display showing the number of boundary condition files that will be generated from this met segment. Surface Observations - Source of observations to use for Segment. Valid Range: Installation dependent Default: None Rawinsonde Observations - Source of upper air observations for Segment. Valid Range: Installation dependent Default: None Fetching Mode - This option menu controls which specific metdata files to gather in the Fetching stage. If set to "ops" then the a mixture of analysis and forecast data will be used. If the menu is set to "fcst" then ONLY forecast data will be used. Valid Range: ops/fcst Default: ops Action Buttons Clear Form - This button will delete all segments, reset the text entries to blank and un-select all option menus. Default - This button will delete all segments, except the first. It will set the first segment to default values. OK - This button will check the Segment data, cause XOMEGA to write out a "met.inp" file in the prep directory and close the dialog box. If any values are in error, a Set Meteorology Error dialog box will pop up alerting the user of the specific errors and suggestions on how to correct them. See Section 9.8.4 for information on the Error dialog box. No "met.inp" file will be written if there are errors in the data. Cancel - This button will decline the Segment data, remove all segments, clear all values, and close the dialog box. There is no confirmation process. Help - This button will open the Help dialog and load this section. Set Meteorology Error While entering values into the text entries if you make errors a dialog box will pop up alerting you of the errors and suggesting ways to correct them. The top part of the dialog box contains the error message and the suggestions. The bottom part has a row with two action buttons: OK - This button will acknowledge the error and dismiss the Error dialog. Help - This button will open the Help dialog and load this section. END Set Meteorology Data