NASA Langley Research Center and its research partners from the University of North Dakota (UND) and the National Center for Atmospheric Research (NCAR) participated in the AIRS II campaign from November 17 to December 17, 2003. AIRS II provided the opportunity to compare TAMDAR in situ in-flight icing condition assessments with in situ data from the UND Citation II aircraft's Rosemont system. TAMDAR is designed to provide a general warning of ice accretion and to report it directly into the Meteorological Data Communications and Reporting System (MDCRS). In addition to evaluating TAMDAR with microphysical data obtained by the Citation II, this study also compares these data to the NWS operational in-flight icing Current Icing Potential (CIP) graphic product and with the NASA Advanced Satellite Aviation-weather Products (ASAP) Icing Severity product. The CIP and ASAP graphics are also examined in this study to provide a context for the Citation II's sorties in AIRS II

Anderson, Mark V.

Cagle, Melinda F.

Daniels, Taumi

Minnis, Patrick

Mulally, Daniel J.

Murray, John J.

Nguyen, Louis A.

Nordeen, Michele L.

Schaffner, Phillip R.

Wolff, Cory A.

NASA Technical Reports Server

43rd AIAA Aerospace Science Meeting & Exhibit 
10- 13 January 2005 / Reno,  NV 
Tropospheric Airborne Meteorological Data and Reporting 
(TAMDAR) Icing Sensor Performance during the 200312004 
Alliance Icing Research Study (AIRS 11) 
John J. ~ u r r a ~ * ,  Louis A. ~ g u ~ e n ' ,  Taumi. S. ~ a n i e l s *  , Patrick   inn is', Phillip R. ~chaffner*;~, Melinda F. cagleT', 
Michele L. ~ordeen"  
NASA Langle), Research Centes, Hainpton, Virginia, 23681 
Cory A. wolf@' 
Natioilal Center for Atr?zospheric Research, Boulder, Colorado, 80301 
Mark V. ~nderson***, Daniel J. ~ u l a l l ~ " ' ,  Kristopher R.   ens en*** 
AirDat, LLC., Ellergreen, Colorado, 80439 
Cedric A. ~rainger"' and David J. ~elene*';** 
Uiliversity of Nortl? Dakota, Grand Forks, Nort11 Dakota, 58202 
NASA Langley Research Center and its research partners from the University of North 
Dakota (UND) and the National Center for Atmospheric Research (NCAR) participated in 
the AIRS I1 campaign from November 17 to December 17, 2003. AIRS I1 provided the 
opportunity to compare TAMDAR in situ in-flight icing condition assessments with in situ 
data from the UND Citation I1 aircraft's Rosemont system. TAMDAR is designed to provide 
a general warning of ice accretion and to report it directly into the Meteorological Data 
Communications and Reporting System (MDCRS). In addition to evaluating TAMDAR 
with microphysical data obtained by the Citation 11, this study also compares these data to 
the NWS operational in-flight icing Current Icing Potential (CIF') graphic product and with 
the NASA Advanced Satellite Aviation-weather Products (ASAP) Icing Severity product. 
The CIP and ASAP graphics are also examined in this study to provide a context for the 
Citation 11's sorties in AIRS 11. 
I. INTRODUCTION 
T HE second Alliance Icing Research Study (AIRS 11) concerned potential and ambient weather that affected in- flight icing conditions in the vicinity of the Mirabel Airport near Montreal, Quebec during the winter of 2003 to 
2004. It was conducted by the bi-national Aircraft Icing Research Alliance under a cooperative agreement 
between the National Research Council of Canada and NASA and included the participation of NOAA, the FAA 
and government and university research laboratories throughout the U.S. and Canada. AIRS I1 was conducted to 
develop techniques to remotely detect, diagnose and forecast hazardous winter conditions at airports and to improve 
weather forecasts of aircraft icing conditions, the characterization of the aircraft icing environment and the overall 
understanding of the icing process and its effect on aircraft1. Data was collected by ground, airborne and space-based 
* Atmospheric Scientist, Chemistry and Dynamics Branch, NASA, MS-401B, Hampton, VA 23681 
' Atmospheric Scientist, Climate Science Branch, NASA, MS-420, Hampton, VA 23681 
* Project Manager, Electromagnetics and Sensors Branch, NASA, MS-473, Hampton, VA 23681 
' Atmospheric Scientist, Climate Science Branch, NASA, MS-420, Hampton, VA 23681 
** 
.La 
Sensor Engineer, Electromagnetics and Sensors Branch, NASA, MS-473, Hampton, VA 23681 
' ' Atmospheric Scientist, Climate Science Branch, NASA, MS-401A, Hampton, VA 23681 
.%.a 
'+ Research Scientist, Analytical Services and Materials, Inc., I Enterprise Parkway, Hampton, VA 23666 
'%tmospheric Scientist, NCAR Foothills Laboratory 4, 3450 Mitchell lane, Boulder, CO 80301 
*** 
. . , 
---
President, Engineering Research and Development, 30746-410 Bryant Dr., Evergreen, CO, 80439 
' ' ' Vice President, Engineering Research and Development, 30746-410 Bryant Dr., Evergreen, CO, 80439 
& A .  , , T  
T'T Engineer, Engineering Research and Development, 30746-410 Bryant Dr., Evergreen, CO, 80439 
'" Professor, Department of Atmospheric Sciences, UND, Grand Forks, ND, 58202 
**A* Assistant Professor, Department of Atmospheric Sciences, UND, Grand Forks, ND, 58202 
1 
American Institute of Aeronautics and Astronautics 
This material is declared a work of the U.S. Government and is not sub-ject to copyright protection in the United States. 
https://ntrs.nasa.gov/search.jsp?R=20050198944 2019-08-29T20:30:51+00:00Z
3 
Figure 9 . CIP Product VT 1900UTC 28Nov03 Figure 10. NASA Icing Severity VT 1715UTC 28Nov03 
The Current Icing Potential Product for 12,000 feet, the level of maximum icing potential is compared to the NASA 
Icing severity index which is obscured over much of the icing region by multi-layered clouds. Areas that are 
amenable to analysis on the satellite product appear to correspond well with the CIP. 
' 
POS DETECT 
NULL DETECT 
IFALSEDETECT 
0 L  I I I ( I  
18.5 19.9 21.2 22.6 
Time (UTC) 
Figure 11. TAMDARIRosemont Comparison, November 28. 
A comparison of TAMDAR icing detection on November 28 with the UND Citation's instrumentation is 
shown in figure 11. Ice was first encountered by the Rosemont system at approximately 18:300 UTC. Following 
initial detection, 41 analysis increments were examined. For these increments, TAMDAR and Rosemont's 
combined agreement for positive and null detections is 68%. Seven missed detections and 6 false detections were 
noted constituting a 32% error rate for this case. 
6 
American Institute of Aeronautics and Astronautics 
E. November 30,2003 Case Study 
The Citation took off from Bangor at 1624 
UTC, arriving over Mirabel at FL350 at about 1730 
as shown in Fig. 11. A spiral descent was made over 
the runway intersection down to FL4O.  Clouds were 
not encountered until about FL72, where there was a 
layer about 1000 ft thick. The lower clouds had tops 
slightly above FLAO, but variable. Several 
measurement passes were made along the runway at 
FLAO going in and out of cloud along the way. In 
cloud, the Citation encountered light to moderate 
rime ice and liquid water contents of 0.1 to 0.4 glm3. 
This was followed by a missed approach over the 
runway from FUO. The cloud extended down to 
slightly below FL20. This was followed by passes at 
FL70 going west to east and missed approaches from 
FL70 over the runway going east to west. This profile 
was carried out several times. In general, the liquid 
water content was higher in the upper cloud layer, 
with larger mean values of the droplet sizes. There 
composed primarily of water droplets. The clouds wer 
well as the vertical. 
Figure 12. Citation I1 November 30,2003 AIRS I1 Sortie 
were a few ice crystals in both layers, but the clouds were 
e well characterized by the measurements in the horizontal as 
a- Ban m.mr m 
GOES-12 ICING INTEE 
Figure 14. NASA Icing Severity VT 1715UTC 30Nov03 
The Current Icing Potential product for November 30, 2003 shown in figure 13 indicates a large area of 
high icing potential at 4000 feet in altitude. The corresponding NASA Icing Severity Index depicted in figure 14 
agrees very well with the CIP for areas of high icing potential as indicated earlier and for areas of little or no icing 
potential such as can be seen over southern Maine. Effective cloud heights for both tops and bases that comprise the 
Icing Severity Index are plotted in Figure 15. This case was examined extensively in earlier work by Nguyen et aL8, 
The satellite retrievals indicated that light icing conditions existed during the first hour of flight where the Citation 
climbed and maintained an altitude above 30,000 feet during the transit from Bangor to Mirabel. Satellite-derived 
cloud bases and tops were estimated at approximately 1,500 and 10,000 feet. As the Citation made a spiral descent 
over the Mirabel runway, the Rosemount started detecting icing at 10,000 feet while the TAMDAR picked up icing 
at 6500 feet during the descent. 
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American Institute of Aeronautics and Astronautics 
UNULL DETECT 
WFALSE DETECT 
WMlSS DETECT 
20 ' I " " I " " I " "  
- 
'Sat med prob icin! 
 sat high prob icin! 
- 
. 
18.5 
Time (UTC) 
Figure 15. TAMDARIRosemont Comparison, November 30. 
A comparison of TAMDAR icing detection on November 30 with the UND Citation's instrumentation is 
also shown in figure 15. Very good correspondence between TAMDAR and Citation instrumentation for the 
detection of icing and null conditions is indicated for this case. Ice was first encountered by the Rosemont system at 
approximately 16:OO UTC. Thereafter, 48 analysis increments were examined. For these increments, TAMDAR and 
Rosemont's combined agreement for positive and null detections is 94%. Three missed detections occurred 
constituting a 6% error rate over the 48 sampling increments. No false alarms were observed. 
E. December 11,2003 Case Study 
The Citation took off from Bangor at 15192, and 
arrived over Mirabel at 35,000 ft at 16142. A spiral 
descent site encountered cloud tops at 29,500 ft. The 
clouds at the high elevations were composed of ice 
crystals. There were several layers of cloud during the 
descent, but no liquid water was encountered until 11,000 
ft, where there were small patches of relatively low (less 
than 0.2 g/m3). The sounding went down to 3,000 ft 
(T=+2.6C), where there were precipitation sized water 
drops. The super-cooled water was between about 11,000 
and 8,000 ft. Horizontal transects were made in 1,000 ft 
intervals parallel to runway 06/24 between these altitudes 
and a missed approach was made from 11,000 ft  down to 
250 ft. The citation then climbed to 29,000 ft to within an 
estimated 500 ft of cloud top at 18382. The aircraft 
11: 15 ISTG 
TDC 
landed in Montreal at 18582. Figure 16. Citation I1 December 11,2003 AIRS II Sortie 
8 
American Institute of Aeronautics and Astronautics 
Figure 17. CIP Product VT 1900UTC 11Dec03 Figure 18. NASA Icing Severity VT 1715UTC 11Dec03 
The Current Icing Potential Product for 10,000 feet, the level of maximum icing potential is compared to the 
NASA Icing severity index which is obscured over most of the icing region by multi-layered clouds. 
I " " I " " I - '  
@NULL DETECT 
IFALSEDETECT 
IMlSS DETECT - 
- - 
- 
I 
I I I I I I I , ,  
17.8 
Time (UTC) 
Figure 19. TAMDARlRosemont Comparison, December 11. 
A comparison of TAMDAR icing detection on December 11 with the UND Citation's instrumentation is shown 
in figure 19. Ice was first encountered by the Rosemont system at approximately 16:300 UTC. Following initial 
detection, 31 analysis increments were examined. For these increments, TAMDAR and Rosemont's combined 
agreement for positive and null detections is 68%. Seven missed detections and 3 false detections were noted 
constituting a 10% error rate for this case. 
IV. TEST RESULTS AND DISCUSSION 
A. TAMDAR Sensor Performance. 
This study provides the first quantitative assessment of TAMDAR icing detection capabilities for a focused 
in-flight icing campaign. The analysis and comparison of the data collected onboard the UND Citation I1 over 
Mirabel, Quebec during the AIRS I1 flight campaign in November and December 2003 indicates that the TAMDAR 
sensor will detect light to moderate in-flight icing at flight levels typically flown by regional commercial aircraft and 
9 
American Institute of Aeronautics and Astronautics 
general aviation. Severe icing conditions were not encountered. Using Rosemont as ground truth, in-flight icing 
detection data from the TAMDAR was evaluated to determine positive, null, missed and false detection rates. 
Overall, for the four cases studied, 132 sample increments were evaluated yielding a combined agreement rate 
between TAMDAR and Rosemont of 77% and a combined error rate of 23%. The bottom row of figure 20 is 
germane. TAMDAR's icing detection capability as compared to the Rosemont ice detector indicates that as a 
general indicator if in-flight icing conditions TAMDAR is effective. The performance statistics warrant further 
investigation to determine if there is a situational or methodological bias inherent in the data or the analysis. 
Figure 20. Comparison of TAMDAR (T) and Rosemont (R) in Cessna Citation I1 Icing Missions 
B. Evaluation of Regional Icing Products. 
This study indicates that the both the CIP and GOES products are generally validated by the two 
independent in situ icing detection systems installed on the Cessna Citation 11. Research on the enhancement of the 
more broadly based CIP with the NASA Icing Severity Index is being conducted jointly by NCAR and the NASA 
Langley Research Center. The extension of the NASA products to produce multi-level indices is also occurring. 
Since the GOES imager views only the tops of the clouds directly, the occurrence of icing below cloud top must be 
derived using the retrieved microphysics combined with additional information such as Rapid Update Cycle RUC 
model output. Additional analyses using a three-dimensional estimate of aircraft icing from the satellites9 should 
provide for a more direct comparison between the satellite, the CIP and aircraft. 
V. ACKNOWLEDGMENTS 
This work was sponsored by the NASA Aviation Safety and Security Program and the NASA Applied 
Science Program. The authors would also like to acknowledge the UND Citation pilots and flight crew, the FAA 
Aviation Weather Research Program In-flight Icing Product Development Team and the Bangor Airport staff for 
their contributions to this research. 
VI. REFERENCES 
' ~ a l l e t ,  J., Isaac, G., Politovich, M., Marcotte, D., Reehorst, A., Ryerson, C., "AIRS I1 Science Plan," [cited July 
7, 20031, URL: http://www.airs-icine.ore/AIRS ILl2003-07-07 AIRS I1 Science Plan.pdf. 
2~aniels ,  T. S., Tsoucalas, G., Anderson, M., Mulally, D., Moninger, W., Mamrosh, R., "Tropospheric Airborne 
Meteorological Data Reporting (TAMDAR) Sensor Development," 11th Col$ on Aviation, Range, arld Aerospace 
Meteorology, Hyannis, MA, American Meteorological Society. 
' ~ u r r a ~ ,  J. J., Schaffner, P.R., Minnis, P., Nguyen, L., Delnore, V.E., Daniels, T.S., Grainger, C.A., Delene, D. 
Wolff, C.A., TAMDAR icing sensor performance during the 2003 Alliance Icing Research Study (AIRS II).", 11th 
Con$ on Aviation, Range, and Aerospace Meteorology, Hyannis, MA, American Meteorological Society. 
'~aniels, T. S., "Tropospheric Airborne Meteorological Data Reporting (TAMDAR Sensor Development," 
2002-02-153, SAE General Aviation Techr~ology Conference arld E,~position, April 16-18, 2002, Wichita, KS. 
5~e lene ,  D.J., University of North Dakota, Aviation Science Program, Cessna Citation I1 webpage, 
http://www.atmos.und.edu/instrumentation.htm. 
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American Institute of Aeronautics and Astronautics 
6~ernstein, B.C., McDonough, F., Politovich, M.P., Brown, B.G., Ratvasky, T.P., Miller, D.R., Wolff, C.A., and 
Cunning, G.C., 2004: Current Icing Potential (CIP): Algorithm description and comparison with aircraft 
observations. Submitted to Journal of Applied Meteorology. 
7 ~ i n n i s ,  P. "Real-time cloud, radiation, and aircraft icing parameters from GOES over the USA". 13"' AMS 
Coilferer~ce or1 Satellite Oceailography arld Meteorology, Norfolk, VA, September 20-24,2004. 
8 Nguyen, L., Minnis, P., Spangenberg, D.A., Nordeen, M.L., Palikonda, R., Khaiyer, M.M., Gultepe, I., and 
Reehorst, A.L., "Comparison of satellite and aircraft measurements of cloud microphysical properties in icing 
conditions during ATRECIAIRS-II.", 11th Coi$ on Aviatiorl, Range, and Aerospace Meteorology, Hyannis, MA, 
American Meteorological Society. 
Minnis, P., Nguyen, L., Palikonda, R., Spangenberg, D.A., Ayers, J.K., Yi, Y., Nordeen, M.L., and Wolff, 
C.A., "Toward a three-dimensional near-real time cloud product for aviation safety and weather diagnoses.", lltlz 
Coi$ oii Aviation, Range, arid Aerospace Meteorologjl, Hyannis, MA, American Meteorological Society. 
I I 
American Institute of Aeronautics and Astronautics 



Tropospheric Airborne Meteorological Data and Reporting (TAMDAR) Icing Sensor Performance during the 2003/2004 Alliance Icing Research Study (AIRS II)

Tropospheric Airborne Meteorological Data and Reporting (TAMDAR) Icing Sensor Performance during the 2003/2004 Alliance Icing Research Study (AIRS II)

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