| 8. New Climatology Tools | ||
|---|---|---|
 | Chapter 2. User Manual |  |
| 8. New Climatology Tools | ||
|---|---|---|
| | Chapter 2. User Manual | |
Climate tools introduced in AvnFPS 3.0 are being replaced. Release 3.2 preserves old GUIs described in the previous section. This section describes three new tools. However, these tools are not yet fully integrated with the rest of AvnFPS. In particular, a NFS access to climate data directory is required, however, that condition should be satisfied for many, if not all, AWIPS workstations. The new tools are started as standalone programs, from the AvnFPS Startup Menu, see Section 1, “Startup Menu”.
![[Important]](docbook-images/important.png) | Important |
|---|---|
| Observations in climate database have a notion of a “nominal” hour. The “nominal” hour is used for time range selection by the utilities described in this section. It is calculated as the full hour of observation time, offset by 10 minutes. That is, all observations with time HH:50 <= observation-time < HH+1:50 have their nominal hour set to HH+1. |
This GUI displays a wind rose for a given month and hour (or a range of hours). You can also specify flight category to further refine the results.
Wind Rose
The winds are displayed in a form of concentric wedges, split into segments reflecting wind speed. The area of each segment is proportional to the total time of wind falling into specific speed/direction category. It is possible to display wind statistics for observations with ceiling/visibility matching selected flight category. The “total hours” value, shown in the lower right corner of the display is calculated as follows:
For a given month, all observations reporting wind are extracted from database, and sorted with respect to observation time. If Flight Cat menu is set to a specific flight category, only observations with this and lower categories are chosen for further analysis.
For each pair of consecutive observations, it is assumed that the wind reported by the first one remains valid till the second one. To avoid gaps in data, a check is performed for the time interval between the observations. If the interval is greater than 1 hour 10 minutes, the pair is rejected. The time counter for the hours (1 - 3) falling within the calculated period is then incremented by appropriate value.
Given selected hour, or hour range, the total hours display is the sum of all the time intervals that match the criteria specified above.
To display wind rose:
Use arrows to set month in the Month counter.
Use the arrows (or spinners) in the Hour counter to select an hour. If you want statistics for a range of hours, set the toggle button Range and type in the range of hours in the window as shown on the image above.
Use the Sites list to see that site's data.
Press the Draw button to draw the wind rose.
![[Note]](docbook-images/note.png) | Note |
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Selecting a toggle or changing hour/month forces redraw. |
The displayed data can be saved to a file as text or graphic and can be printed. Those features are accessible through the Menu Bar.
File Menu
To save statistics to a text file:
Select the Save Stats menu item.
Type the file name in the popup dialog, then press Save.
An example output file:
KBUF Jan
HOUR: 00Z
TOTAL: 991.8
CALM: 20.7
SPEED: 0-5 kt 5-12 kt 12-20 kt 20+ kt
VRB: 0.0 0.5 0.0 0.0
349-011: 5.5 16.2 1.5 0.0
011-034: 3.2 25.5 3.5 0.0
034-056: 10.7 32.2 3.9 0.4
056-079: 11.9 49.2 16.5 0.0
079-101: 1.5 21.8 4.0 0.0
101-124: 2.2 14.5 0.0 0.0
124-146: 4.0 17.0 2.1 0.0
146-169: 6.7 29.1 3.5 2.0
169-191: 3.3 35.2 11.1 1.0
191-214: 7.1 22.6 30.4 3.4
214-236: 3.4 42.4 52.7 19.1
236-259: 7.4 59.5 96.3 52.5
259-281: 3.6 41.1 68.6 9.2
281-304: 4.0 20.5 30.7 1.7
304-326: 3.5 16.0 4.1 2.1
326-349: 3.1 21.2 5.3 0.0
HOUR: 01Z
TOTAL: 989.8
CALM: 18.1
SPEED: 0-5 kt 5-12 kt 12-20 kt 20+ kt
VRB: 0.0 0.0 0.0 0.0
349-011: 3.8 14.6 3.0 0.0
011-034: 5.2 13.4 2.8 0.0
...
To save image to a file:
Select the Save Image menu item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.
To print image:
Select the Print Image menu item.
If needed, type in printer destination:
lpr -P printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK
To change wind speed thresholds and corresponding colors and to set number of wind directions use the Configure menu item. This will display a configuration dialog.
Configuration Dialog
To change wind speed thresholds, enter appropriate values in the 3 available windows. Number of wind speed categories cannot be changed.
To change colors, press a button to the right of the wind speed label/entry. A color editor will be shown.
Use Points menu to select number of wind rose compass points, 8, 16 or 36.
Press OK to accept the changes. You may save the changes in a file, use Save.
The Ceiling and Visibility Distribution GUI displays distribution of visibility and ceiling by month and hour. The display is in a form of a stacked histogram.
Visibility Distribution by Hour
All ceiling and visibility data is extracted from the database. The timespan of a weather event is calculated similarily as in Wind Rose application. That is, observation are sorted with respect to time, the timespan of an observation is assumed to be the window between two consecutive observations, or 1 hour 10 minutes, whichever is less. The histogram and the table below displays relative time of occurence of weather resulting in all flight categories.
To display hourly distribution:
In the Plot Type frame, select the By Hour toggle.
In the Element frame, you can select the weather element to display by selecting radio button Ceiling or Visibility. If you want to see the flight category distribution, select Joint option.
Use the arrows in the Month frame to select a month. If you want statistics for the range of months, set the Range toggle button and type in the range of months in the text window, as shown on the image above.
Use the Sites list for the site of interest.
Press the Draw button to draw the histogram.
To display hourly distribution, proceed as above, but select By Month toggle. Note that the selection area in the lower left corner changes its label from Monthto Hour. You can select either single or range of hours.
Ceiling Distribution by Month
| Note |
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It may take up to a minute to retrieve statistics from climate data file. To speed up display, the toolkit uses a caching mechanism: the data is retrieved only once and then stored in a file, to be read on subsequent displays. |
| Note |
|---|---|
Selecting a toggle or changing hour/month forces redraw. |
The displayed data can be saved to a file as text or graphic and can be printed. Those features are accessible through the Menu Bar. The menu items are the same as for Wind Rose, with the exception of Configure. To save statistics to a text file:
Select the Save Stats item.
Type the file name in the popup dialog, then press Save.
An example output file:
KBUF (1973-2004)
HOUR: 00Z Ceiling Visibility
MONTH LIFR IFR MVFR LIFR IFR MVFR TOTAL
Jan 39.52 81.17 342.10 30.22 110.87 98.00 990.72
Feb 37.12 56.15 241.07 18.83 92.23 86.27 894.00
Mar 49.17 61.98 166.23 24.65 81.68 81.65 990.00
Apr 32.20 43.88 107.10 9.85 47.07 45.47 959.00
May 25.90 25.87 61.73 8.92 39.53 68.35 989.90
Jun 8.75 15.75 45.08 2.05 38.75 77.45 960.00
Jul 3.85 9.47 38.67 0.60 33.75 91.88 990.00
Aug 5.85 12.27 45.07 2.85 56.83 102.83 991.10
Sep 10.58 26.82 74.77 1.10 32.13 82.77 957.10
Oct 17.70 32.20 111.68 2.80 25.65 52.92 991.00
Nov 43.70 43.43 179.17 11.43 52.60 71.43 958.10
Dec 37.70 56.27 294.07 27.90 74.35 59.38 999.10
HOUR: 01Z Ceiling Visibility
MONTH LIFR IFR MVFR LIFR IFR MVFR TOTAL
Jan 47.18 73.40 326.52 27.35 116.60 97.13 988.83
...
To save image to a file:
Select the Save Image item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.
To print image:
Select the Print Image item.
If needed, type in printer destination:
lpr -P
printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK
The Ceiling and Visibility Trend GUI displays forecast of visibility and ceiling given initial conditions. The display is in a form of a histogram.
Visibility Trend
To display ceiling/visibility trend:
Use the Sites list for the site of interest.
Use the Date, Hour, Wind Direction, Wind Speed, Ceiling, Visibility and Precip widgets to set initial conditions. Each of the widgets contains a blue arrow indicating current value and a red strip/sector which is used to set matching criteria for searching similar events in climatological database. Left button moves value or an edge of range. Middle button is used to move both value and range. In the "Wind Direction" widget use right button to toggle between wind arrow and a circle representing calm or variable wind.
Or, you can start with the most recent METAR. Select the Get button to retrieve the observation from the text database. The Decode button then initializes the selection widgets for you.
| Note |
|---|---|
| The text window in which the METAR appears is editable. |
In the Element frame, select the weather element or, to display flight category, Joint toggle.
Press the Draw button to draw the histogram.
By default, a 6-hour forecast is displayed. You can change number of hours to 3, 6, or 12 from the Hours option menu.
The displayed data can be saved to a file as a graphic and/or can be printed out. Those features are accessible through the Menu Bar. To save image to a file:
Select the Save Image item.
Type the file name in the popup dialog. To specify file format, use one of the extensions: .ps, .jpg, .png. Press Save.
To print image:
Select the Print Image item.
If needed, type in printer destination:
lpr -P
printer
If the -P option is not specified, the image will be printed on your default printer.
Press OK
This tool searches climate database for events similar to those selected. If a matching event is found, the whole time period, i.e., user-specified time range, is marked as a match. In the second stage, for each matched period, observations with the nominal hours within the time range and number of hours selectable from the Hours menu are extracted. Minimum values of ceiling and visibility from observations for each nominal hour within the forecast range are used to determine flight category for the forecast hour. Relative frequency is displayed as a stacked histogram. The table below the histogram graphic shows percentage of occurence of each flight category.
| Important |
|---|---|
| COUNT is the number of matching periods NOT the number of observations. COUNT will always be less than or equal of number of observations matching the selection criteria. Several matching observations within the same period do not increase the count. The reason for this is to not introduce bias in the calculations, as is typically the case when IFR conditions often result in increased observation frequency, compared to VFR (e.g. SKC) conditions. |
The Date widget selects range of dates, lower and upper value inclusive. The month/day pair is converted to the day of the year. Leap years are not taken into account: If the selected date range consists of Feb 29 only, the search will use day 60 of the year, leap day or not.
The Hour widget allows resolution up to 1 minute. However the search is done for full hours. Lower and upper values of the selected range are converted to nominal hours. For example, range 1252-1452 sets selection limits to be 13-15, which will pick up observations within the time interval 1250-1550.
The Ceiling widget has to allow for an half-open interval (i.e. 5100 feet and up, sky cover over 50%) and unlimited ceiling. This requirement results in peculiar behavior of the red rectangle used to select range using the mouse. For example, if you want restrict ceilings to above 5000 feet, the rectangle should be reduced to a line at 51+.
| Note |
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Database stores values in metric system (inherited from NCDC data files). The conversion between those and Imperial (US) units is never exact, consequently it is often impossible to guarantee selection of a single value, such as 3000 ft. |
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| 7. Climatology Tools |  | Appendix A. Editor Key Bindings |