Help for java ACARS Display
HELP FOR THE MAP (the main page)
Detailed video tutorials are available at http://acweb.fsl.noaa.gov/videos/.
- Move the mouse cursor over the map to display data
whenever the cursor is over a data point. The data shown is,
clockwise from the upper right:
- altitude in ft (assuming a standard atmosphere)
- altitude in mb (true)
- Aircraft ID (FSL's unique encoded value)
- Origin and -> Destination airports
- Wind direction and speed (kts)
- Temperature (Celsius)
- Observation time (UTC)
- To zoom, drag the mouse (hold
the mouse button down
while moving the mouse) diagonally across a region to
create a zoom box. When you release the mouse button, the
zoom-boxed region will zoom to fill the screen. (The zoom-box
shape may not follow the mouse cursor as you expect. This is
because the zoom-box is constrained to have the same aspect
ratio as the overall map.)
- Click on an ascent or descent portion of a
flight track to produce a sounding, which will come up in a
separate window. Ascent and descent segments that are likely
to provide useful soundings are
indicated by solid lines. (See
instructions below on how to use the sounding window.)
the mouse anywhere on a flight track to get
textual data (in a separate window).
- Shift-click (hold down shift while clicking
the mouse) anywhere on the display to reveal a window with map
parameters that can be used in setting a new default map.
- Drag one of the orange balls on the altitude
bar on the right to change the altitude range
displayed. If you are displaying a limited altitude range, you
can also drag the color bar between the balls to shift the
range. Click anywhere on the altitude bar to
(re)display the entire altitude range.
- Use the
WindSpd button to
color-code data by
wind speed rather than by altitude.
- Use the
Barbs button to display
or hide wind
- Drag the orange ball on the min spacing slider
to show fewer data. (This is particularly useful when
displaying wind barbs.)
- Use the
Overlays button to
display or hide
airports and/or U.S. VORs. (The name, location and
elevation will be
displayed when the cursor is over the airport or VOR.)
HELP FOR SOUNDINGS (the soundings window)
Once you have clicked on the map to generate a sounding, it
will appear in the sounding window. Sounding points further
than 100 nm from the airport are coded in
The sounding consists of a Skew-T plot, a hodograph or flight track
map, and a wind speed
plot. The following thermodynamic indices are also shown, if
A parcel may be specified by clicking with the mouse
at any point.
The parcel will ascend from that point (using the environmental
dewpoint at that pressure), and regions of CAPE and CIn
will be indicated. The Lifted Condensation Level (cloud
base) for the parcel is
indicated by a short horizontal black line on the parcel
trajectory. Right-clicking with the mouse will bring up a
selection window that will allow you to select the initial parcel
dewpoint, temperature, and pressure. Click on a sounding's
button to remove the parcel trajectory. Thanks to
Tom Whittaker of the University of Wisconsin for providing
the core of the code that performs this task.
- CAPE (Convective Available Potential Energy) in J/Kg
- CIn (Convective inhibition) in J / Kg
- PW (Precipitable water) in Kg/m^2
- Helic (storm-relative helicity) in m^2/s^2
- TT (Total Totals index)
- KI (K index)
- LI (Lifted index)
- SW (Showalter index)
- LCL (Lifted Condensation Level)
- iCAPE (approximate CAPE based on the
lifting of a parcel that you input)
- iCIn (approximate CIn based on the
lifting of a parcel that you input)
- iLCL (LCL based on the lifting of a parcel that you input)
(Against Tom's advice, and to facilitate
stability calculations using ACARS soundings that often lack humidity
iCIn are calculated using
the temperature difference between the parcel and the sounding, rather
than the virtual temperature difference. According to Doswell and
Rasumssen (1994, Weather and Forecasting,
9, pp 625-629), this may cause errors > 30% for
values of CAPE below 500 J/Kg and similar errors in CIn, but smaller
error for larger values.)
The hodograph shows wind speed in kts, and height in km. For aircraft
soundings, the hodograph window optionally shows the bearing and range
from the airport to the aircraft. A "Toggle button" in the hodograph
window switches between the two.
The sounding has two default altitude ranges, one extending up to 150
mb and the other to 10 mb. Each of these ranges can be
zoomed by dragging the mouse diagonally across the
portion of the Skew-T plot desired. Unzoom by
clicking a 'scale' button.
(To drag, hold the mouse button
down while moving the mouse. When you release the mouse button, the
zoomed region will fill the plot.) (The zoomed region will have the
same aspect ratio as the main plot, so the red rectangle that appears
may not follow the mouse quite the way you think it should.)
Some aircraft, because of hardware limitations, report altitude as
below 17,000 ft (the AMDAR standard is to always
report altitude with respect to a standard atmosphere). For these
aircraft, we use barometric-altitude if standard pressure altitude
is not available. On sounding plots, the temperature trace is shown
in brown is the altitude reported was barometrically adujsted.
Other functions are as follows:
Move the mouse along the sounding to see the
following printed at the level of the mouse point (from left to
In addition, the temperature and pressure for the cursor point is
indicated below the cursor.
- The pressure in mb, and the pressure altitude in km and feet.
(For ACARS data, the time, bearing and range from the airport are
- The dewpoint in Celsius (and also Fahrenheit below 750 mb).
- The temperature in Celsius (and also Fahrenheit below 750 mb).
- The wind direction and speed in knots.
- A highlighted wind barb.
- A highlighted portion of the wind speed curve.
- A highlighted portion of the hodograph or flight track
Click on the Load Other Soundings button to pop up the
choose sounding window. In this window you
- Enter a 3- or 4-letter
ACARS-airports site name.
(Contact Bill Moninger if your
favorite METAR site is missing.)
- OR, enter a latitude and longitude (in decimal,
with west and south being negative), separated by a comma.
- Enter a starting valid time by choosing a year, month, day, and
- Enter the number of hours of soundings you would like to
display. MAPS (RUC) soundings are generally available
for the past 16 hours, and for intermittent hours up to 36 hours
into the future.
Remember that RAOBs are only available at 0
UTC and 12 UTC.
- Click on a data source,
Soundings will appear one after another on the
plot as soon as they're ready, and a button with
each sounding's information will appear below the plot.
Once a sounding is loaded, you can use its button to (re)display
- Click on a button to clear the display, and
display one sounding.
It generally takes less than a second for an already-loaded
sounding to reappear.
- Shift-click one or more buttons to
add additional soundings
to the plot. (Shift-click means hold down the shift key while
clicking the mouse button.)
- Control-click a sounding's button to remove
the sounding and its button.
The sounding information shown on each button consists of the site
name, and a code:
R indicates a RAOB sounding
P indicates a Profiler sounding
A indicates a sounding from a MAPS analysis
a indicates a sounding from a RUC-2 analysis
Fn indicates a sounding from a MAPS n-hour
fn indicates a sounding from a RUC-2 n-hour
- For instance "DEN(F9)" indicates that the
sounding data are from a MAPS forecast based on an analysis from 9 hours
before the indicated valid time.
Dn indicate ACARS ascent or
descent soundings, respectively.
HELP FOR PRINTING
Unfortunately, java doesn't have convenient printing capabilities, so you
will have to use a screen capture program, or cut-and-paste, to
capture and print windows showing graphical data. In Microsoft
Windows, you can use alt+prtscn to capture the browser window, then
to paste the image into MS paint or some graphics manipulation
package. You can crop the imaage by drawing a box around the area of
interest, then select, copy, and paste the cropped region into, for
instance, powerpoint or word. We have also had good experiences with
HyperSnap-Dx, a shareware program from Hyperionics.
In Unix, a shareware program called XView does the job.
For java windows that show textual data, you can copy the data in the usual
way and paste it into another program for printing, e-mailing, or
Known bugs, or "issues"
- Satellite images are not supported
Solid lines connect data points that can
probably make useful soundings. Lines are shown if:
- Barbs are not being shown, and
- The max altitude of the flight is > 10,000 ft, and
- The minimum (pressure) altitude of the aircraft is
within 2000 ft of the (true) elevation of the airport, and
- There is no data gap greater than 2500 ft in altitude
for data points below 10,000 ft.
Data points taken within the last 20 min (with respect to the
latest time loaded) are plotted at twice the size of other
points (unless barbs are being displayed).
Buttons on the map window:
Several of the buttons reveal other windows. These windows can be
closed in the normal way, or by clicking the button again.
(If a button is indented, it means its corresponding window is
displayed, but it may be covered by other windows. To bring a window
to the front, click the indented button twice.)
- Load lets you load data. Over a 28.8k modem, it
takes about 7 sec per hour of data. To save
time, it is possible to load data of only a particular type or
with a particular location. On a slow connection, this can
speed up loading. But, the program on our
server that subsections the data is itself slow, so you may be
better off downloading the entire data set for a particular
time range. The latest option loads the
latest n hours of data.
- Select lets you display data from various
sensors and/or sources.
Available sensor types are
Data sources are probably of interest to
quality control researchers. Possible data sources are
- g - vertical acceleration data. THESE DATA ARE
KNOWN TO BE INCORRECT!
- edr - eddy dissipation rate (a measure of turbulence).
These data are not quality-controlled and should
not be used for turbulence verification. We
expect quality-controlled edr data to be available
sometime in 2005.
- vapor - only 9 vapor sensors remain good (Feb 2003), and
these will fail over the next several months.
- vg - vertical gust. These data are believed to be correct.
- icing - this is experimental icing data
from Delta airlines, in support of an FAA sponsored
- ACARS - data found in only the ACARS
data stream (i.e., decoded by FSL)
- MDCRS - data found in only the MDCRS
data stream (i.e., decoded by ARINC)
- ACARS & MDCRS - data found in BOTH the
ACARS and MDCRS data streams.
- AMDAR - AMDAR data
- TAMDAR - TAMDAR data
- WindSpd lets you color-code the observations
by wind speed.
- Barbs lets you display or hide wind barbs.
- Soundings reveals the Soundings window.
- Un-zoom undoes your most recent zoom or roam.
- Default sets the projection to your default
map. If you haven't set a default, this will be the U.S.
(Lambert Conformal Conic Projection.) To set a default map
other than the U.S., follow the
defaults link above the display.
- World sets the projection to the world
(Cylindrical Equidistant). Zooming in on any region of the
world will result in a Lambert Conformal Conic projection of
the zoomed-in region.
- Overlays lets you display or hide various
overlays, such as Airports and U.S. VORs.
When these are displayed, moving the cursor over
an an will display its identification.
- Lat/Lon readout indicates the position of the
- Overview reveals an overview window, which shows
where your zoomed region is. You can drag the little
window that shows in the Overview window to change the focus of
(roam) the big map. The Un-zoom button also undoes roaming.
- Soundings are identified with the origin or destination airport
listed in the ACARS reports. This is unlike what is done in
the non-java displays in which soundings are associated with
the nearest airport. We hope this new identification
will be more accurate.
- Clicking the right button, or shift-clicking (holding down the
shift key and clicking the left mouse button) anywhere on a
flight track will generate
textual output for the entire flight.
The columns in this
output should be self-explanatory, with the exception of the
first two columns on the left. The first, "S", is the data
source. Possible values are
The second column, "F" is the data quality flag. Its possible
- 0 - data found in the ACARS data stream (i.e., decoded
by FSL) only
- 1 - data found in the MDCRS data stream (i.e., decoded
by ARINC) only
- 2 - data found in BOTH the ACARS and MDCRS data streams.
- 3 - AMDAR data
- 4 - TAMDAR data
- 9 - data source not determined (before Feb 2003)
- 0 - good data
- 1 - bad temp
- 2 - bad wind
- 3 - both bad
- the above value + 4 if the altitude was
Please send comments or suggestions to Bill Moninger at Bill.Moninger@noaa.gov.
If you're reporting a problem, please indicate what
browser (with version number), operating system, and hardware you are
running on. Also, it would be helpful if you could open your
browser's 'java console' and send me the last several
[ FSL |
Prepared by Bill Moninger,
Last modified: Tue Nov 17 17:26:16 GMT 2009