Investigation of systematic effects in atmospheric microthermal probe data.

114 Pages·1.2 MB·en_US

by  Roper, Daniel S.;Walters, Donald L.

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valPostgraduateSchool (Ifapplicable) NavalPostgraduateSchool
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TITLE(IncludeSecurityClassification)
VESTIGATIONOFSYSTEMATICEFFECTSINATMOSPHERICMICROTHERMALPROBEDATA
.PERSONALAUTHOR(S) DanielS.Roper
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ister'sThesis From To December1992 106
SUPPLEMENTARYNOTATION
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BviewsexpressedinthisthesisarethoseoftheauthoranddonotreflecttheofficialpolicyorpositionoftheDepartmentofDefenseortheU.S.
vernment.
.COSATICODES 18.SUBJECTTERMS(continueonreverseifnecessaryandidentifybyblocknumber)
:IELD GROUP SUBGROUP opticalturbulence,diurnalvariation,thermocoupleresponse,microthermalprobes,
thermosonde,propagation
.ABSTRACT(continueonreverseifnecessaryandidentifybyblocknumber)
Tiepropagationofelectromagneticradiationthroughtheatmosphereisacrucialaspectoflasertargetacquisitionandsurveillancesystems
disvitaltotheeffectiveimplementationofsomeTheaterMissileDefensesystems. Atmosphericturbulencedegradestheimageorlaserbeam
alityalonganopticalpath. Duringthepastdecade,theU.S.AirForce'sGeophysicsDirectorateofPhillipsLaboratorycollectedhighspeed
ferentialtemperaturemeasurementsoftheatmospherictemperaturestructureparameter,CT2,andtherelatedindexofrefractionstructure
rameter,C„2 The stratosphericresultsshowa1-2orderofmagnitudeincreaseindayturbulencevaluescomparedtonight. Resolving
ethertheseresultswererealoranartifactofsolarcontaminationisacriticalTheaterMissileDefenseissue.
ThisthesisanalyzedthethermosondedatafromanexperimentalprogramconductedbytheGeophysicsDirectorateinDecember1990and
indstrongevidenceofsolarinducedartifactsinthedaytimethermalprobedata. Inaddition,thisthesisperformedatheoreticalanalysisofthe
armalresponseversusaltitudeoffinewireprobesbeingusedinanewthermosondesystemunderdevelopmentattheNavalPostgraduate
100I. Experimentalwindtunnelmeasurementswereconductedtovalidatetheanalyticalpredictions.
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Approved for public release; distribution is unlimited.
Investigation of Systematic Effects in
Atmospheric Microthermal Probe Data
by
Daniel S. Roper
Captain, United States Army
B.S., United States Military Academy, 1982
Submitted in partial fulfillment
of the requirements for the degree of
MASTER OF SCIENCE IN PHYSICS
from the
NAVAL POSTGRADUATE SCHOOL
December 1992
ABSTRACT
The propagation ofelectromagnetic radiation through the atmosphere is a crucial aspect
oflaser target acquisition and surveillance systems and is vital to the effective implementation
ofsome Theater Missile Defense systems. Atmospheric turbulence degrades the image or laser
beam quality along an optical path. During the past decade, the U.S. Air Force's Geophysics
Directorate ofPhillips Laboratory collected high speed differential temperature measurements
of the atmospheric temperature structure parameter, Cj.2 and the related index of refraction
,
structure parameter, C 2 The stratospheric results show a 1-2 order ofmagnitude increase in
n .
day turbulence values compared to night. Resolving whether these results were real or an
artifact of solar contamination is a critical Theater Missile Defense issue.
This thesis analyzed the thermosonde data from an experimental program conducted by
the Geophysics Directorate in December 1990 and found strong evidence of solar induced
artifacts in the daytime thermal probe data. In addition, this thesis performed a theoretical
analysis of the thermal response versus altitude of fine wire probes being used in a new
thermosonde system under development at the Naval Postgraduate School. Experimental wind
tunnel measurements were conducted to validate the analytical predictions.
in
am
TABLE OF CONTENTS
INTRODUCTION
I. 1
BACKGROUND 4
II.
A. THEORY 4
B. STRUCTURE FUNCTIONS AND PARAMETERS 6
C. CURRENT APPLICATIONS 9
D. PREVIOUS RESULTS 10
DIURNAL VARIATION 15
III.
A. DIURNAL VARIATION EXPERIMENT 2 15
Purpose 15
1.
2. Experimental Procedure 15
3. Experimental Conditions 17
a. 4 December 1990 17
b. 5 December 1990 17
c. 6 December 1990 17
d. 7 December 1990 17
e. 8 December 1990 18
IV
.
DUDLEYKNOXLIBRARY
NAVALPOSTGRADUATESCHOOL
MONTEREY. CALIFORNIA 93943-5002
RESULTS AND ANALYSIS OF DIURNAL VARIATION
B.
EXPERIMENT 2 19
Data Reduction 19
1
2. Statistical Methodology 19
3. Results 21
a. Diurnal Variation 21
b. 7 December 1990 26
c. 8 December 1990 31
4. Analysis 37
C. DVE SUMMARY 41
D. SONDE STABILIZATION FOR SUBSEQUENT EXPERIMENTS 42
.
PROBE RESPONSE 44
IV.
A. PROBE RESPONSE TIME AS A FUNCTION OF DECREASING
TEMPERATURE AND AIR DENSITY 44
1. Thermocouple Measurement Limitations Due to Probe
Response Time 44
2. Fluid Characteristics and Heat Transfer 45
a. Forced Convection 45
b. Viscosity 46
c. Kinematic Viscosity 47
d. No-Slip Condition 48
..
e. Reynolds Number, Re 48
Nusselt Number 51
f.
g. Rate of Convective Heat Flow 54
h. Convective Heat Transfer Coefficient, h 54
c
B. TIME CONSTANT, r 57
1 Theoretical Probe Response 57
2. Thermocouple Characteristics 59
Thermocouple Type 59
(1)
Material Properties 60
(2)
Thermocouple Geometry 60
(3)
3. Theoretical Calculation of r 62
C. EXPERIMENTAL VERIFICATION OF PROBE RESPONSE TIME 65
.
Empirical Formula For Probe Thermal Response 65
1
2. Wind Tunnel Test 65
3. Experimental Results 68
4. Comparison of Experiment vs. Theoretical Calculations ... 69
D. PROBE RESPONSE SUMMARY 74
CONCLUSIONS AND RECOMMENDATIONS 76
V.
CONCLUSIONS 76
A.
RECOMMENDATIONS 77
B.
VI