Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging
Defining the averaging time required for measuring meaningful turbulence statistics is a central problem in boundary-layer meteorology. Path-averaging scintillation instruments are presumed to confer some time-averaging benefits when the objective is to measure surface fluxes, but that hypothesis ha...
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ftdtic:ADA421359 2023-05-15T15:01:53+02:00 Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging Andrea, Edgar L. Fairall, Christopher W. Persson, P. O. Guest, Peter S. ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB 2003-12 text/html http://www.dtic.mil/docs/citations/ADA421359 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA421359 en eng http://www.dtic.mil/docs/citations/ADA421359 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Meteorology Statistics and Probability Fluid Mechanics *PROBABILITY DISTRIBUTION FUNCTIONS *TURBULENCE *METEOROLOGY RATIOS FLUX(RATE) PATHS REFRACTIVE INDEX TIME SERIES ANALYSIS BOUNDARY LAYER SURFACES SCALE HYPOTHESES BUDGETS HEAT BENEFITS CONFIDENCE LIMITS SCINTILLATION COUNTERS BETA PARTICLES ARCTIC OCEAN Text 2003 ftdtic 2016-02-21T07:39:10Z Defining the averaging time required for measuring meaningful turbulence statistics is a central problem in boundary-layer meteorology. Path-averaging scintillation instruments are presumed to confer some time-averaging benefits when the objective is to measure surface fluxes, but that hypothesis has not been tested definitively. This study uses scintillometer measurements of the inner scale of turbulence l(sub 0) and the refractive index structure parameter (C(sup, sub n)) collected during SHEBA (the experiment to study the Surface Heat Budget of the Arctic Ocean) to investigate this question of required averaging time. The first conclusion is that the beta probability distribution is useful for representing; C(sup 2, sub n) and l(sub 0) measurements. Consequently, beta distributions are used to set confidence limits on C(sup 2, sub n) and l(sub 0) values obtained over various averaging periods. When the C(sup 2, sub n) and l(sub 0) time series are stationary, a short-term average of C(sup 2, sub n) or l (sub 0) can be as accurate as a long-term average. But, as with point measurements, when time series of path- averaged C(sup 2, sub n) or l (sub 0) values are nonstationary, turbulent surface fluxes inferred from these C(sup 2, sub n) and l (sub 0) values can be variable and uncertain-problems that path-averaging was presumed to mitigate. Since nonstationarty turns out to be a limiting condition, the last topic is quantifying the nonstationarty with a published nonstationarty ratio and also by simply counting zero-crossings in the time series. Text Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean Defense Technical Information Center: DTIC Technical Reports database Arctic Arctic Ocean |
institution |
Open Polar |
collection |
Defense Technical Information Center: DTIC Technical Reports database |
op_collection_id |
ftdtic |
language |
English |
topic |
Meteorology Statistics and Probability Fluid Mechanics *PROBABILITY DISTRIBUTION FUNCTIONS *TURBULENCE *METEOROLOGY RATIOS FLUX(RATE) PATHS REFRACTIVE INDEX TIME SERIES ANALYSIS BOUNDARY LAYER SURFACES SCALE HYPOTHESES BUDGETS HEAT BENEFITS CONFIDENCE LIMITS SCINTILLATION COUNTERS BETA PARTICLES ARCTIC OCEAN |
spellingShingle |
Meteorology Statistics and Probability Fluid Mechanics *PROBABILITY DISTRIBUTION FUNCTIONS *TURBULENCE *METEOROLOGY RATIOS FLUX(RATE) PATHS REFRACTIVE INDEX TIME SERIES ANALYSIS BOUNDARY LAYER SURFACES SCALE HYPOTHESES BUDGETS HEAT BENEFITS CONFIDENCE LIMITS SCINTILLATION COUNTERS BETA PARTICLES ARCTIC OCEAN Andrea, Edgar L. Fairall, Christopher W. Persson, P. O. Guest, Peter S. Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
topic_facet |
Meteorology Statistics and Probability Fluid Mechanics *PROBABILITY DISTRIBUTION FUNCTIONS *TURBULENCE *METEOROLOGY RATIOS FLUX(RATE) PATHS REFRACTIVE INDEX TIME SERIES ANALYSIS BOUNDARY LAYER SURFACES SCALE HYPOTHESES BUDGETS HEAT BENEFITS CONFIDENCE LIMITS SCINTILLATION COUNTERS BETA PARTICLES ARCTIC OCEAN |
description |
Defining the averaging time required for measuring meaningful turbulence statistics is a central problem in boundary-layer meteorology. Path-averaging scintillation instruments are presumed to confer some time-averaging benefits when the objective is to measure surface fluxes, but that hypothesis has not been tested definitively. This study uses scintillometer measurements of the inner scale of turbulence l(sub 0) and the refractive index structure parameter (C(sup, sub n)) collected during SHEBA (the experiment to study the Surface Heat Budget of the Arctic Ocean) to investigate this question of required averaging time. The first conclusion is that the beta probability distribution is useful for representing; C(sup 2, sub n) and l(sub 0) measurements. Consequently, beta distributions are used to set confidence limits on C(sup 2, sub n) and l(sub 0) values obtained over various averaging periods. When the C(sup 2, sub n) and l(sub 0) time series are stationary, a short-term average of C(sup 2, sub n) or l (sub 0) can be as accurate as a long-term average. But, as with point measurements, when time series of path- averaged C(sup 2, sub n) or l (sub 0) values are nonstationary, turbulent surface fluxes inferred from these C(sup 2, sub n) and l (sub 0) values can be variable and uncertain-problems that path-averaging was presumed to mitigate. Since nonstationarty turns out to be a limiting condition, the last topic is quantifying the nonstationarty with a published nonstationarty ratio and also by simply counting zero-crossings in the time series. |
author2 |
ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB |
format |
Text |
author |
Andrea, Edgar L. Fairall, Christopher W. Persson, P. O. Guest, Peter S. |
author_facet |
Andrea, Edgar L. Fairall, Christopher W. Persson, P. O. Guest, Peter S. |
author_sort |
Andrea, Edgar L. |
title |
Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
title_short |
Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
title_full |
Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
title_fullStr |
Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
title_full_unstemmed |
Probability Distributions for the Refractive Index Structure Parameter and the Inner Scale of Turbulence and Their Implications for Flux Averaging |
title_sort |
probability distributions for the refractive index structure parameter and the inner scale of turbulence and their implications for flux averaging |
publishDate |
2003 |
url |
http://www.dtic.mil/docs/citations/ADA421359 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA421359 |
geographic |
Arctic Arctic Ocean |
geographic_facet |
Arctic Arctic Ocean |
genre |
Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean |
genre_facet |
Arctic Arctic Ocean Surface Heat Budget of the Arctic Ocean |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADA421359 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
_version_ |
1766333880406638592 |