Solution and difficulty for flux measurement over ocean using Eddy Covariance System

• Main Authors: Yuan-Lung Chen, 陳元隆
• Other Authors: 莊秉潔
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/01773720141890260371

碩士 === 國立中興大學 === 環境工程學系所 === 95 === While using Eddy Covariance System to observe the atmospheric flux in the marine environment, there are many problems that must be overcomed, such as: rock, rotation, and movement. Most energy are stored under sea surface, thus, we must measure energy storage in ocean to understand energy behavior. Moreover, it will be reduced useful data when the observed lens of the Li7500 open path CO2/H2O analyzer is covered with water droplet, fog, sea salt, and so on. First, we designed a mobile platform to simulate the shaking condition in the ocean and used Gyro to measure partial angles of anemometer along three axes (roll, pitch, and yaw). We corrected atmospheric flux with two kinds of correction methods, and chose better one by statistics values (OLS, RMSE, MAE,BIAS) .Second, In Chung Hsing lake, water temperature was measured in different depth to estimate energy storage. We try to understand whether it is feasible or not that estimating the energy storage of water body from the temperature probe observation. And the auto-sprayer can clean salt upon observed lens when the Li7500 open path CO2/H2O Analyzer were observed on boat. In shaking case, relational coefficient of vertical wind speed raise from 12% to 43 %. The relational coefficient of wind direction raise from 59 % to 89 %. After sea correction, the flux was not better than original. It is found the surface energy budget was imbalanced, the turbulent heat flux was 33 % lower than the available surface heat flux during the NCHU Lake study period. After using 2-axis rotation correction with WPL term, the energy closure gap is reduced to 28 %. The application of auto-sprayer can certainly get rid of the substance covered on the observed lens and make sure that the data is authentic 5 minutes after cleaning lens.