Modeling approach for estimating biogenic VOCS emission and CO2 assimilation of vegetation in Taiwan

• Main Authors: YU,JHIH-YUAN, 游智淵
• Other Authors: CHANG,KEN- HUI
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/99489p

博士 === 國立雲林科技大學 === 工程科技研究所 === 105 === The emission of BVOCs is considered an important part of causing light smoke. Taiwan Air Quality Model was used for O3 simulation, the simulated results with TBEIS-2 emission match well with the observed data than that with TBEIS emission. The average daily O3 maximum concentration for the simulated 5-day data Only underestimate 5.2 ppb from TBEIS-2, more than underestimate 12.6 ppb from TBEIS. The O3 simulation results from TAQM with TBEIS-2 was improved the accuracy. The goal of the present study is to provide a comprehensive model to estimate CO2 assimilation and emission flux in Taiwan, called Taiwan Carbon Dioxide Assimilation Model (TEPM). Chang et al. (2009) have developed a model, called Taiwan Biogenic Emission Inventory System (TBEIS). There is another function in LEAFC3 to compute the CO2 assimilation flux due to Leaf-level net photosynthesis of plants. Therefore, based on the photosynthetic algorithm in LEAFC3 and combined with the database in TBEIS, an hourly time step model that couples major processes controlling short-term forest CO2 exchanges for Taiwan is established in this study. To possess the capability of simulation for seasonal variation with LAI change, the NDVI-LAI transfer function, where LAI data are transformed from NDVI, has been also added to TEPM. Based on the meteorological data in 2007, the annual total amount of CO2 assimilation about 115.3 million ton in Taiwan. The CO2 assimilation amount is higher in the third quarter (July–September) and lower in the first quarter (January–March) for 44.3% and 16.4% of the annual total amount respectively. The annual total amount of CO2 assimilation about 90.5 million ton from evaluation for NDVI-LAI transfer function used in TEPM. The second quarter (Apirl–June) and third quarter (July–September) was about 76.8% of the annual total amount. Seasonal variation of CO2 assimilation is very important in Taiwan. Predicted CO2 uptake and release fluxes show a relatively good correlation with observed data (R2 = 0.67) In general, the simulated results of TEPM on the daytime showed a slightly underestimated CO2 uptake flux due to photosynthesis effect with mean normalized bias of 35%, while those on the nighttime presented a significantly underestimated CO2 release flux due to respiration effect with mean normalized bias of -118%. The best assimilation flux of tree in Taiwan was 5,975 ton km-2 y-1 form Acacia trees, the second was 5,603 ton km-2 y-1 form natural Broadleaf forest, the third was 5,521 ton km-2 y-1 form Broadleaf forest, the lowest was 700 ton km2 y1 form旱田.The first five of tree the same low BVOCS emitted, found that the top tree high CO2 assimilation the same low BVOCS emitted use are Acacia trees、Broadleaf forestand Formosan Ash. The best CO2 assimilation the same native species is Acacia trees