Barbre, Robert E., Jr.

Brenton, James

Burns, K. Lee

Curtis, Nathan

Decker, Ryan

Huddleston, Lisa

Leahy, Frank

Orcutt, John

Roberts, Barry

White, Patrick

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Analyses of Kennedy Space Center Tropospheric Doppler Radar Wind
Profiler Data for Space Launch System Program Certification
Presentation to the Significant Role of Calibration/Validation and High Performance Computing for
the Transition of Research to Operations Session: Part I, of the Ninth Conference on Transition of
Research to Operations, as part of the 99th American Meteorological Society Annual Meeting
Robert E. Barbré, Jr.1
With co-authors listed alphabetically by last name:
James Brenton1, Dr. K. Lee Burns1, Nathan Curtis2, Ryan Decker2, Dr. Lisa 
Huddleston3, Frank Leahy2, John Orcutt1, Barry Roberts2, and Patrick White2
1Jacobs Space Exploration Group
2NASA Marshall Space Flight Center Natural Environments Branch
3NASA Kennedy Space Center Weather
Phoenix, AZ
9 Jan 2018
https://ntrs.nasa.gov/search.jsp?R=20190000730 2019-08-30T10:08:11+00:00Z
Agenda
2
1. Purpose
2. Certification Requirements
3. Data
4. Analyses
5. Summary
Purpose
• Explain the requirements and analyses performed to certify the Kennedy Space Center (KSC) 
Tropospheric Doppler Radar Wind Profiler (TDRWP) for use in Space Launch System Program 
(SLSP) day-of-launch (DOL) integrated vehicle performance assessments for commit to launch 
decision.
• Requirements are based on SLS vehicle response characteristics to the wind profile, consistency to 
previous databases used in vehicle design assessments, and DOL operational considerations. 
3
Certification Requirements
4
• For effective vertical resolution (EVR), the maximum wavelength of gust analyses is based on accounting for a 30-minute 
assessment.
– EVR quantifies the vertical extent of the smallest feature that an instrument can resolve.
– Boundary wavelength using Aerospace Corporation equation (Spiekermann et al. 1999) yields 768 m.
– Set criterion to 700 m to add conservatism.
Requirement Criteria Rationale
Time Interval 5 min Supports DOL timeline
Vertical Data Interval 150 m Consistent with database used for SLS design
Data Collection Period One year
Analyzing available data over one year of
continuous operation produces statistically 
significant results over all seasons
Wind Accuracy
1.5 m/s root-mean-
square component 
difference
Accuracy of heritage balloon and DRWP systems
Altitude 2,700 - 15,250 m Consistent with database used in SLS design
Reliability
No criterion.  Will report 
the percent of usable 
profiles.
Consistent with the method Shuttle used to 
certify the Automated Meteorological Profiling 
System (AMPS)
Effective Vertical Resolution 700 m
Based on maximum wavelength of gust analyses 
during SLS design
Data: Summary of Datasets
5
• Collected AMPS balloon and TDRWP data for the period of record (POR) 06/22/2016 – 06/22/2017.
• Implemented quality control (QC) algorithms on both datasets.
• Balloon
– One-second AMPS high- and low-resolution profiles (1,159 profiles).
– A total of 98 profiles failed altitude (50 kft) or shear (0.15 s-1 over 100 ft) check.
– An additional 31 profiles failed duplicate profile (5-min) check, leaving 1,030 profiles available for analysis.
• TDRWP [no QC]: Data as archived by MSFC Natural Environments Branch (EV44).
• TDRWP [QC]: 
– QC based off Barbré (2012).
– Automated checks for unrealistic values, possible convection, and parameters that exceeded shear, vertical velocity, temporal and 
vertical consistency, spectral width, and first-guess propagation (FGP) thresholds.
– Manual checks to flag suspect or erroneous data that passed automated checks and to confirm convection. 
Analyses: Time Interval, Vertical Data Interval, Data 
Collection Period
6
• Examined TDRWP [no QC].
• Time interval passes criteria under nominal operations.
• Vertical data interval passes criteria.
• Data were collected over a calendar year (348 days available).
Analyses: Wind Accuracy and Altitude Methodology
7
Small delta between TDRWP and 
balloon winds
Large delta between TDRWP and 
balloon winds
• Averaged all 1-s balloon data within 75 m of each TDRWP 
altitude.
• Temporally matched balloon and TDRWP data throughout 
balloon ascent.
• Utilized 287 comparisons spaced by at least 24 hours to 
maintain sampling independence.
• Examined five-panel plots of each comparison. 
• Delta between concurrent balloon and TDRWP measurements includes 
measurement errors from both systems, as well as the deltas due to 
spatial separation. Reference Eq. (1).
• Quantified RMS deltas due to spatial separation using the North 
American Regional Reanalysis (NARR) (Curtis et al. 2019).
• NARR profiles are coarse and do not capture small scale wind features. 
Therefore, a small scale component must be added to the spatial 
separation determined from the NARR. 
• Utilizing the calculated estimate of small scale features accounts for 
balloon errors. Reference Eq. (2).
• Solve for the TDRWP error. Reference Eq. (3).
Analyses: Wind Accuracy and Altitude Methodology, 
Isolating TDRWP Error
8
Variable list
∆TDRWP-balloon difference between a concurrent TDRWP and balloon report
ETDRWP difference attributed to TDRWP measurement errors 
Eballoon difference attributed to balloon measurement errors
∆spatial estimate of expected differences due to spatial separation
∆spatial,NARR estimate of expected differences due to spatial separation from NARR
∆small estimate of expected differences due to small-scale features for which 
the NARR does not account 
∆small,calc calculated estimate of expected differences due to small-scale 
features for which the NARR does not account 
𝛥𝑇𝐷𝑅𝑊𝑃−𝑏𝑎𝑙𝑙𝑜𝑜𝑛
2 = 𝐸𝑇𝐷𝑅𝑊𝑃
2 + 𝐸𝑏𝑎𝑙𝑙𝑜𝑜𝑛
2 + 𝛥𝑠𝑝𝑎𝑡𝑖𝑎𝑙,𝑁𝐴𝑅𝑅
2 + ∆𝑠𝑚𝑎𝑙𝑙
2 Eq. (1) 
𝛥𝑠𝑚𝑎𝑙𝑙,𝑐𝑎𝑙𝑐
2 = 𝛥𝑠𝑚𝑎𝑙𝑙
2 + 𝐸𝑏𝑎𝑙𝑙𝑜𝑜𝑛
2 Eq. (2)
𝐸𝑇𝐷𝑅𝑊𝑃 = 𝛥𝑇𝐷𝑅𝑊𝑃−𝑏𝑎𝑙𝑙𝑜𝑜𝑛
2 − 𝛥𝑠𝑝𝑎𝑡𝑖𝑎𝑙,𝑁𝐴𝑅𝑅
2 − 𝛥𝑠𝑚𝑎𝑙𝑙,𝑐𝑎𝑙𝑐
2 Eq. (3)
Substitute Eq. (2) into Eq. (1) and solve for ETDRWP to obtain:
Plots provided by N. Curtis / EV44
Analyses: Wind Accuracy Results
9
• Subtracted the RMS delta due to large-scale 
spatial separation and the RMS delta due to 
accounting for small-scale wind features (which 
include balloon error) from the initial TDRWP-
balloon computation.
• Rounded ETDRWP to the nearest 0.1 m/s to account 
for instrument precision. Wind speed is provided to 
the nearest 0.1 m/s.
• Plot shows RMS wind component delta = X for 
profiles between 1.795 km and Y km. 
• Results yield an altitude range of 1,795 – 19,280 m 
where the wind accuracy meets the criteria of      
1.5 m/s RMS wind component delta.
Altitude Range: 
1,795 – 19,280 m
Analyses: EVR
10
• Methodology (Merceret 1999)
– Used data from 2.70-15.25 km from 
days containing at least 100 five-
minute pairs.
– Preprocessing
• Removed linear trend.
• Applied Parzen window on entire 
profile.
– Computed the daily mean 
coherence.
• Power spectral density (PSD) of each 
profile within pair.
• Cross-spectral density (CSD) of each pair.
– Computed sample-weighted mean 
coherence and PSD. 
• Results: estimated EVR of the TDRWP 
is 450 m.
– Coherence crosses 0.25 at 379.5 m and 
415.4 m for U and V, respectively.
– Slope of mean PSDs appear to flatten 
(going from right to left) around 400-500 m.
– Similar results noted when assessing the 
entire altitude range. 
Summary
11
• The TDRWP passes criteria for SLSP certification.
Requirement Criteria Pass / Fail w/Remarks
Time Interval 5 min Pass
Vertical Data Interval 150 m Pass
Data Collection Period One year Pass
Wind Accuracy
1.5 m/s root-mean-square 
component difference
Root-mean-square differences pass criterion from 1,795-
19,280 m.
Altitude 2,700 - 15,250 m
Pass, altitude range within which wind accuracy passes 
envelopes the criteria.
Reliability
No criterion.  Will report the 
percent of usable profiles.
Probability of obtaining a usable profile per requirement is 
86.5%. Probability of obtaining any profile is 93.8%.
Effective Vertical Resolution 700 m Pass, EVR estimated at 450 m.
References
• Barbré, R.E., Jr., 2012. Quality control algorithms for the Kennedy Space Center 50-MHz Doppler Radar Wind Profiler winds 
database. Journal of Atmospheric and Oceanic Technology. Vol. 29. PP. 1731-1743.
• Barbré, R.E., Jr., 2016. Results of the Kennedy Space Center Tropospheric Doppler Radar Wind Profiler Operational Acceptance 
Test. Jacobs ESSSA Group. Contractor Report ESSSA-FY16-3075. Enclosure to NASA MSFC Memorandum EV44 (16-011).
• Curtis, N., F. Leahy, and R. Barbré, Jr., 2019. Analyzing Error in Balloon-Based Wind Measurements due to Spatial Separation 
using the North American Regional Reanalysis. 19th Conference on Aviation, Range, and Aerospace Meteorology. Phoenix, AZ. 
Jan 6-10, 2019.
• Merceret, F. J., 1999. The Vertical Resolution of the Kennedy Space Center 50-MHz Wind Profiler. Journal of Atmospheric and 
Oceanic Technology. Vol. 16. PP. 1273-1278.
• Merceret, F. and J. Ward, 2006: Spatial Properties of Wind Differences in the Lowest Three Kilometers of the Atmosphere. 86th
Annual AMS Meeting. P10.8. Atlanta, GA.
• Schumann, R.S., G. E. Taylor, F. J. Merceret, T. L. Wilfong, 1999. Performance Characteristics of the Kennedy Space Center 50-
MHz Doppler Radar Wind Profiler Using the Median Filter/First-Guess Data Reduction Algorithm. Journal of Atmospheric and 
Oceanic Technology. Vol. 16. PP. 532-549.
• Spiekermann, C.E., B.H. Sako, and A.M. Kabe. 1999. Indentifying Slowly-Varying and Turbulent Wind Features for Flight Loads 
Analyses.  Aerospace Coorporation Report No. TR-99(1534)-2. Prepared for Space and Missile Systems Center Air Force 
Material Command. Los Angeles, CA. Contract No. F04701-93-C-0094.
• Wilfong, T., 2012. AMPS II Eastern Range Formal DT&E Analysis. Tim Wilfong and Associates, LLC. Prepared for ITT 
Corporation Spacelift Range Systems. Contract #F04701-01-C-001. PO #63925W., CO.
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Analyses of Kennedy Space Center Tropospheric Doppler Radar Wind Profiler Data for Space Launch System Program Certification

Analyses of Kennedy Space Center Tropospheric Doppler Radar Wind Profiler Data for Space Launch System Program Certification

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