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Aircraft Data: Geographic Distribution, Acquisition, Quality

Control, and Availability

Work at NOAA/ESRL/GSD and elsewhere

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AMDAR data -- definition

• AMDAR - Aircraft Meteorological DAta Relay

• The generic term for all automated meteorological reports from commercial aircraft

• GSD receives (from a variety of sources) and distributes (with restrictions) all AMDAR data

• Most AMDAR data are used in GSD’s, and NCEP’s weather models

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Flavors of AMDAR data

• MDCRS data (to be discussed by Al)• E-AMDAR (Europe and Africa)• “AMDAR” (Asia and Australia)• Canadian (Canada, inc. flights into U.S.)• TAMDAR (U. S. experimental)• Other experimental

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MDCRS data (24 hours)

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E-AMDAR data

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“AMDAR” data (China, Japan, Australia, New Zealand, So. Africa)

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Canadian data (jets and turboprops)

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TAMDAR data (turboprops, generally below 20 Kft)

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Experimental Turbulence (EDR) data, from UAL (above 20Kft) and TAMDAR (problematic)

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Experimental Icing data from TAMDAR and (sometimes) Delta

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Availability

• Real-time data are restricted to governments, researchers, etc.*

• Graphical displays are available at– http://amdar.noaa.gov/

• Binary and text data are available from MADIS– http://madis.noaa.gov/– data > 48 h old are unrestricted– archival data back to July 2001– many tools for subsectioning data

• GSD is a research, not operational organization– nonetheless, data flows have been pretty steady

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*Data Restrictions

• Described at http://amdar.noaa.gov/FAQ.html

• Worked out over 15 years between NOAA and the participating US airlines

• Generally, non-commercial research users may have access to real-time data, if their work is of potential benefit to airlines

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AMDAR QC in the U.S.

• NCEP (Brad Ballish) is the official U.S. data quality center– http://www.nco.ncep.noaa.gov/pmb/qap/

• GSD provides many research QC products based on the Rapid Update Cycle (RUC)

• Another U.S. center doing excellent work: Pat Pauley at the Naval Research Laboratory

• Many non-U.S. centers also perform AMDAR QC

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AMDAR QC at GSD

• We look at differences between AMDAR observations and 1h forecasts from various versions of the RUC model

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The Rapid Update Cycle

• An hourly cycle• Ingests all available data each hour

– AMDAR, TAMDAR, RAOBS (0 & 12 Z), Satellite, Surface, etc., etc.

• Covers the CONUS• We run many RUC cycles• For AMDAR QC, we use a 20 km cycle

called “dev2”

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RUC - AMDAR Comparisons

• Statistical results are available at http://amdar.noaa.gov/ruc_acars/

and include:– Time series for individual aircraft– 3 and 7 day interactive statistics– plan view of data and corresponding RUC

values– (summary statistics are open; real-time data

are restricted)

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Plan view showing Wind-

rejects for TAMDAR.

Reject reason indicated.

Overall statistics shown

http://amdar.noaa.gov/ruc_acars/

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Right column shows the RUC reject code for any

rejected variable(s)

“sp=0”: wind speeds of 0 are rejected.

This information is downloaded automatically by some users.

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7-day summary statistics (sortable). New columns show the fraction of obs rejected by the RUC, for each variable.

We reject many TAMDAR winds because we don’t accept descent winds currently

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Current AMDAR Data Quality

• Generally as good or better than RAOBs• To check, we compare AMDAR and RAOBs with

RUC 1h forecasts• (RUC is not the “truth”, but, when a long time

period is aggregated, can serve as a common denominator)

• Results to follow are from– 1-31 Dec. 2006– AMDAR data from 0 UTC +/- 30 minutes

• 200 - 800 observations per pressure level• Canadian jets and all turboprops excluded

– In the Great Lakes Region• 13 RAOBs at 0 UTC

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AMDAR - dev2 1h fcst Temperature RMS difference for obs taken near 0 UTC

Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

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Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

Green shows RAOB

AMDAR - dev2 1h fcst Temperature RMS difference for obs taken near 0 UTC

AMDAR and RAOBs show very similar statistics

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T bias is small (< 0.5°C) for AMDAR.

(Generally AMDAR ascents are warmer than descents, but not at low levels during this winter month.)

Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

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T bias is small (< 0.5°C) for AMDAR and RAOBs.

RUC shows a slight warm bias wrt RAOBs.

Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

Green shows RAOB

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For RMS of the vector wind difference with the RUC…

Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

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For RMS of the vector wind difference with the RUC, AMDAR and RAOB show similar values at all levels.

Red shows AMDAR ascents and en-route

Blue shows AMDAR descents

Green shows RAOB

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Water Vapor

• Most AMDAR measurements don’t include vapor information

• WVSS-II measures it, but recent data is problematic

• TAMDAR measures it– In lower troposphere only (below 500 mb,

18 Kft)– In U. S. Midwest only– We’ll look at recent TAMDAR results

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Relative Humidity RMS (wrt RUC dev2) for data taken near 0 UTC

Red shows aircraft ascents and en-route

Blue shows aircraft descents

TAMDAR (open circles)

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TAMDAR (open circles)

RAOBs (green)

TAMDAR RH differences with RUC are generally smaller than RAOB RH differences.

An encouraging result.

Red shows aircraft ascents and en-route

Blue shows aircraft descents

Relative Humidity RMS (wrt RUC dev2) for data taken near 0 UTC

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Summary

• AMDAR is an extensive, accurate, and timely data source

• We thank the airlines for providing the data• Tools at NCEP and GSD have been very helpful

in evaluating– Aircraft performance– Model behavior

• Feedback to and from airlines, researchers, and other nations has been invaluable in improving quality.