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AMDAR Forecast Applications

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Title: AMDAR Forecast Applications


1
AMDAR Forecast Applications
  • JMA Meeting
  • March 23, 2009
  • Carl Weiss
  • NWS Aviation Services Branch

2
Before We Begin
  • You may have heard aircraft data referred to
    as ACARS, MDCRS, or TAMDAR
  • ACARS (Aircraft Communications, Addressing, and
    Reporting System) is the name of a datalink
    service provided by Aeronautical Radio, Inc. that
    sends data between aircraft and ground stations
  • MDCRS (Meteorological Data, Collection and
    Reporting System) is the weather portion of the
    ACARS data stream provided by seven major U.S.
    air carriers
  • TAMDAR (Tropospheric Airborne Meteorological DAta
    Reporting) data are provided by a private
    company, AirDat, who uses regional air carriers

However, Aircraft Meteorological DAta Relay
(AMDAR) is the preferred term by the WMO and NWS.
3
AMDAR Data Have Many Applications
  • Aviation
  • Low level wind shear
  • Ceilings and visibilities
  • Icing and turbulence
  • Winter Storms
  • Precipitation type
  • Lake effect snow
  • Thunderstorms
  • Convective initiation
  • Calculation of stability indices
  • Fire Weather
  • Mixing heights
  • Haines indices
  • Relative humidity forecasts
  • Marine Forecasts
  • Small craft and Gale Warnings
  • Hazardous Materials Support
  • AMDAR can be used to support HAZMAT teams

4
Aviation Applications
  • AMDAR soundings in vicinity of airports provide
    meteorologists a real time view of the atmosphere
  • This can result in more accurate forecasts of low
    clouds, fog, low level wind shear and other
    aviation weather elements
  • AMDAR flight level data provide important
    information in flight corridors
  • TAMDAR aircraft report icing and turbulence data

5
Low-Level Wind Shear
  • AMDAR data can be useful in determining the
    presence of low-level wind shear (LLWS)
  • Aircraft ascending or descending in the vicinity
    of an airport are in an ideal location for
    depicting low-level wind shear

6
Low-Level Wind Shear
  • An example of this was noted by the forecasters
    at the Green Bay, WI WFO on the evening of
    October 29, 2005
  • The TAF that night indicated LLWS was forecast to
    begin after 0600 UTC. TAMDAR soundings from
    around 0120 UTC showed LLWS already was present

7
Low-Level Wind Shear
8
Low-Level Wind Shear
  • The forecaster was able to update the TAF and
    begin the LLWS more than 3 hours earlier than did
    the prior forecast
  • This was mentioned in the Area Forecast
    Discussion that was issued around
    0245 UTC

9
Ceilings and Visibilities
  • AMDAR provides very useful information for
    forecasting low ceilings and fog that can greatly
    impact airports
  • Water vapor information is a very important
    element, but soundings without it can still be
    useful

10
Ceilings and Visibilities
  • The Detroit, MI WFO found TAMDAR data useful in
    forecasting a dense fog event on the evening of
    February 4, 2005
  • Soundings indicated light winds in the boundary
    layer, moisture near the surface and dry air
    above
  • Normally, these are suitable conditions for the
    formation of low clouds or fog

11
Ceilings and Visibilities
12
Ceilings and Visibilities
  • Forecasters at Detroit amended their TAF for the
    09 to 12 UTC period, reducing visibilities to ½
    mile. The METAR observations below show that
    visibilities dropped even lower.
  • Kdtw 0532z 00000kt 2sm br clr
  • Kdtw 0739z 17003kt 1 3/4sm br r04/1000v3500
  • Kdtw 0936z 17004kt 1/4sm fg r04/0500v0600
  • Kdtw 1154z 16004kt 1/4sm fg r04/2800v0600

13
Icing and Turbulence
  • The U.S. Air Force Weather Agency (AFWA) used
    TAMDAR data to verify an icing forecast from
    their MM5 model.

14
Icing and Turbulence
15
Icing and Turbulence
Is icing occurring over Michigan?
Icing PIREPS for all levels 1600-1800 UTC
16
Icing and Turbulence
Yes! icing near TVC and PLN
Yes! Icing near TVC and PLN
Automated aircraft reports of icing and
turbulence will help AFWA and the AWC in the
forecast and verification of these aviation
hazards.
17
Winter Storms
  • Precipitation type forecasts can be made with
    greater accuracy with the use of AMDAR data
  • Frequent soundings show the height of the
    freezing level, and the presence of elevated warm
    layers - knowledge of such features is critical
    for accurate precipitation type forecasts

18
Winter Storms (Precipitation Type Forecasts)
  • On December 15, 2005 forecasters at the Buffalo,
    NY WFO used AMDAR soundings to identify a
    substantial warm layer between 2,000 and 5,000
    feet above the ground
  • Because there was such a deep layer of warm air,
    the forecast was updated to reduce snow
    accumulations and increase the amount of sleet
    and freezing rain

19
Winter Storms (Precipitation Type Forecasts)
20
Winter Storms (Precipitation Type Forecasts)
21
Convective Forecasts
  • AMDAR data have been used extensively in support
    of convective forecasts
  • Temperature and moisture data provide the needed
    information to determine the stability of the
    atmosphere
  • Wind data can be used to construct hodographs

22
A Convective Non-Event
A linear mesoscale convective
system was located over eastern
Minnesota and western Wisconsin at
1500 UTC on June 7, 2005.
23
A Convective Non-Event
It was thought initially that this
elevated convection would become surface based
as the system moved east during the
day A Severe Thunderstorm Watch was
issued for much of Wisconsin at 1530 UTC.
24
A Convective Non-Event
  • Shortly after the issuance of the watch,
    forecasters at the Green Bay, WI WFO noticed that
    TAMDAR soundings from the watch area appeared
    much too stable for surface based convection
  • A sounding from the Central Wisconsin airport at
    1512 UTC showed a strong capping inversion, that
    was unlikely to break
  • Another sounding at 1923 UTC showed the
    atmosphere was still much too stable for
    convection -forecasters then lowered the chance
    for thunderstorms, and the watch was later dropped

25
A Convective Non-Event
1512 UTC Sounding
1923 UTC Sounding
26
A Convective Non-Event
  • The thunderstorms that prompted the severe
    thunderstorm watch never became surface based as
    they moved east
  • Forecasters had been misled by model soundings
    that predicted the cap would erode sufficiently
    for surface based storms to form
  • Misleading forecast guidance became a less
    frequent issue as more forecasters used AMDAR data

27
A Convective Non-Event
RUC Forecast (black) was much less stable than
TAMDAR sounding (purple)
28
Fire Weather
  • Accurate fire weather forecasts require an
    understanding of atmospheric stability, wind and
    moisture
  • The large spatial and temporal gaps in
    radiosonde data make this difficult
  • locations distant from radiosondes are at
    particular disadvantage
  • AMDAR data can fill many of these gaps and are
    now used increasingly in fire weather forecasts

29
Fire Weather
  • Forecasters found AMDAR data useful in expanding
    a Red Flag Warning in effect for Northern and
    Central Wisconsin on the afternoon of July 15,
    2006.
  • Very dry air could be seen on TAMDAR soundings
    earlier in the day when the Red Flag Warning was
    issued. Later soundings indicated sufficient dry
    air in other parts of the forecast area to expand
    the warning
  • Temperature gt75F, RH lt25, winds of 25 mph

30
Fire Weather
  • AREA FORECAST DISCUSSION...UPDATEDNWS GREEN BAY
    WI200 PM CDT SAT JUL 15 2006
  • .UPDATED...ADDED AREAL COVERAGE FOR THE RED FLAG
    HEADLINES. RH/S ALREADY IN THE 20 PCTS EARLY
    THIS AFTERNOON AND WINDS NEAR CRITERIA OVER NW
    WI. TAMDAR SOUNDING THIS AM FROM RHI SHOWS A VERY
    DRY AIR MASS TO MIX DOWN WITH NEAR CRITIERIA
  • WINDS.

31
Fire Weather
32
Marine Applications
  • Surface winds and resulting waves are influenced
    greatly by both winds aloft and stability
  • Unstable air helps mix down strong winds above
    the boundary layer, while stable conditions
    hinder mixing
  • AMDAR data are ideal for determining both winds
    aloft and atmospheric stability

33
Marine Applications
  • AMDAR data have been used in the Great Lakes
    region and along the coastlines of the United
    States for marine forecasts
  • The following is an example from October 3, 2004.
    The Chicago, IL WFO forecasters used AMDAR data
    to determine that the atmosphere was sufficiently
    unstable to mix down 35 knot winds to the surface
  • Based on this information, they wisely decided to
    continue the Gale Warning that had been issued
    earlier in the day

34
Marine Applications
  • AREA FORECAST DISCUSSION
  • NATIONAL WEATHER SERVICE CHICAGO IL
  • 715 PM CDT SUN OCT 3 2004
  • .MARINE...SHIP REPORTS OF GALES THIS EVENING FROM
    THE
  • SOUTHWEST. SURFACE ANALYSIS AND USING THE ACARS
    SOUNDING FROM ORD AT 2230 UTC SHOW STRONG WINDS
    ALOFT AND BEHIND THE FRONT. WILL KEEP THE GALE
    WARNING FOR OVERNIGHT.
  • WHW

35
Marine Applications
36
Hazardous Materials Support
  • AMDAR data are used frequently by the National
    Transportation Safety Board in the investigation
    of aviation and marine accidents
  • AMDAR data were used in support of the September
    11th disaster
  • AMDAR data can be used in local models to predict
    the drift of hazardous materials

37
Hazardous Materials Support
  • HYSPLIT - Hybrid Single Particle Lagrangian
    Integrated Trajectory model is an Air Resources
    Laboratory (ARL) model used for computing air
    parcel trajectories in dispersion and deposition
    simulations
  • HYSPLIT dispersion model simulations were run
    centered over the Miami International Airport
    starting at 01 UTC on the evening of November 27,
    2008
  • The model was first run using just the 12km NAM.
    The model was run again, using temperature,
    dewpoint, and wind information from commercial
    aircraft.
  • The outputs from the HYSPLIT runs are quite
    different, especially in the first two hours, and
    likely due to the inaccurate model forecast of
    the low level winds by the NAM.

38
Hazardous Materials Support

Aircraft sounding from Miami International Airport
Sounding from an
aircraft equipped with a WVSS2 water vapor sensor
39
Hazardous Materials Support
  • HYSPLIT Output

The figure on the left is the output of HYSPLIT
run with the 18Z NAM, while the one on the right
is the same HYSPLIT run with aircraft data.
There are significant differences, especially in
the first hour. The HYSPLIT model forecasts the
pollutant to drift to the northeast from the
start, while the HYSPLIT model with aircraft data
forecasts the pollutant to go in the opposite
direction for the first hour before drifting to
the northeast.
40
Hazardous Materials Support
After the first hour
The first hour of the HYSPLIT run with aircraft
data brings the pollutant in the opposite
direction, over the Fountainbleau and Sweetwater
areas.
The first hour of the HYSPLIT model brings the
pollutant over the Virginia Gardens and Miami
Springs areas.
41
Hazardous Materials Support
  • After hour two

The second hour of HYSPLIT run with aircraft data
forecasts the pollutant almost entirely
southwest of the source point.
The second hour of the HYSPLIT model forecasts
the pollutant entirely northeast of the source
location.
42
Hazardous Materials Support
Results
  • If this had been an actual event, using model
    data only in the HYSPLIT run could have led to
    the wrong area being warned
  • The HYSPLIT run with only model data was probably
    incorrect because the NAM model did not
    accurately forecast the weak sea breeze that
    reached the Miami area during late afternoon
  • It would appear that manually entered data from
    aircraft, VAD Wind Profiles or radiosondes can
    result in improvements to the HYSPLIT model
    forecasts

43
Questions?
  • Carl Weiss
  • National Weather Service, W/OS23
  • SSMC2, Rm. 13326
  • 1325 East-West Highway
  • Silver Spring, MD 20910 USA
  • (301) 713-1726x149
  • carl.weiss_at_noaa.gov
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