Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types
碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 100 === Abstract Eddy-covariance (EC) system has been used to measure exchange of scalars, momentum and energy components between land surface and atmosphere in the past decades. But the limitations and assumptions of EC method s...
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ndltd-TW-100NTU051360142015-10-13T21:45:45Z http://ndltd.ncl.edu.tw/handle/47850399742706646333 Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types 大氣穩定度對不同地表類型之可感熱通量擴尺度研究 Chao-Jung Fan 范釗榮 碩士 國立臺灣大學 地理環境資源學研究所 100 Abstract Eddy-covariance (EC) system has been used to measure exchange of scalars, momentum and energy components between land surface and atmosphere in the past decades. But the limitations and assumptions of EC method such as being a point-measurement make EC method uncertain over complex terrain. To systematically quantify area-averaged energy fluxes, comparing between energy fluxes measured by EC method and surface-layer scintillometer (SLS) over hilly terrain and estuarial grass marsh is studied in this research. SLS system applied Monin-Obukhov Similarity Theory (MOST) to estimate sensible heat fluxes by linking variances and covariances of laser beam intensity within path-length between laser transmitter and receiver and SLS system was established at Xitou flux tower during summer and winter, and at Guandu Nature Park during winter. Owing to the measurement within path-length, SLS system provides better spatial representative than conventional tower-based EC results. In this study, surface parameters and properties such as friction velocity, Bowen ratio and surface roughness length are investigated to understand the features of turbulence formation in each site. Results suggest the under-estimated sensible heat flux by scintillometer and an explanation to the difference of measurement is established under various atmospheric conditions. In this study, it’s concluded that at Xitou, SLS measures about 0.35 times of sensible heat flux to that by EC under stable state and the correlations y=0.76x2-0.56x+1.76 and y=1.56x2-2.07x+1.81 could describe the relationship between logarithm of stability and H ratio under unstable state in winter and summer respectively. At Guandu, the H ratio is constantly 0.9 under stable state and in correlation y=3.25e-0.044x-2.14 between logarithm of stability and H ratio under unstable state. The relationship between results of EC and SLS could be a linkage among tower-based studies and high-scale methods such as remote sensing and be estimated to be a base to regional micrometeorological modeling. Jehn_Yih Juang 莊振義 2012 學位論文 ; thesis 71 en_US |
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碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 100 === Abstract
Eddy-covariance (EC) system has been used to measure exchange of scalars,
momentum and energy components between land surface and atmosphere in the past
decades. But the limitations and assumptions of EC method such as being a
point-measurement make EC method uncertain over complex terrain. To systematically
quantify area-averaged energy fluxes, comparing between energy fluxes measured by
EC method and surface-layer scintillometer (SLS) over hilly terrain and estuarial grass
marsh is studied in this research. SLS system applied Monin-Obukhov Similarity
Theory (MOST) to estimate sensible heat fluxes by linking variances and covariances of
laser beam intensity within path-length between laser transmitter and receiver and SLS
system was established at Xitou flux tower during summer and winter, and at Guandu
Nature Park during winter. Owing to the measurement within path-length, SLS system
provides better spatial representative than conventional tower-based EC results. In this
study, surface parameters and properties such as friction velocity, Bowen ratio and
surface roughness length are investigated to understand the features of turbulence
formation in each site. Results suggest the under-estimated sensible heat flux by
scintillometer and an explanation to the difference of measurement is established under
various atmospheric conditions. In this study, it’s concluded that at Xitou, SLS measures
about 0.35 times of sensible heat flux to that by EC under stable state and the
correlations y=0.76x2-0.56x+1.76 and y=1.56x2-2.07x+1.81 could describe the
relationship between logarithm of stability and H ratio under unstable state in winter
and summer respectively. At Guandu, the H ratio is constantly 0.9 under stable state and
in correlation y=3.25e-0.044x-2.14 between logarithm of stability and H ratio under
unstable state. The relationship between results of EC and SLS could be a linkage among tower-based studies and high-scale methods such as remote sensing and be
estimated to be a base to regional micrometeorological modeling.
|
author2 |
Jehn_Yih Juang |
author_facet |
Jehn_Yih Juang Chao-Jung Fan 范釗榮 |
author |
Chao-Jung Fan 范釗榮 |
spellingShingle |
Chao-Jung Fan 范釗榮 Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
author_sort |
Chao-Jung Fan |
title |
Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
title_short |
Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
title_full |
Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
title_fullStr |
Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
title_full_unstemmed |
Upscaling Parameterization of Sensible Heat Flux under Different Atmospheric Stability Conditions across Various Land Surface Types |
title_sort |
upscaling parameterization of sensible heat flux under different atmospheric stability conditions across various land surface types |
publishDate |
2012 |
url |
http://ndltd.ncl.edu.tw/handle/47850399742706646333 |
work_keys_str_mv |
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