Proposal of wide-area CO2 concentration fluctuation evaluation technology using multi-point observation type green space evaluation index

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04716
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22050:Civil engineering plan and transportation engineering-related
• Research Institution: Ibaraki University
• Principal Investigator: Kuwahara Yuji 茨城大学, 理工学研究科(工学野), 教授 (80272110)
• Co-Investigator(Kenkyū-buntansha): 藤田 昌史 茨城大学, 理工学研究科(工学野), 准教授 (60362084)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: CO2濃度 / 簡易センサ / 土地被覆 / DOAS法

Outline of Final Research Achievements

During an attempt to measure trace gases at a lake, differential optical absorption spectroscopy (DOAS) measurement equipment failed, causing delays to the experiment. Consequently, an integrated green-space evaluation index of the lake ecosystem could not be proposed. To overcome this issue, technologies were developed to more accurately analyze the observation environment. First, the effects of coverage and observation time on the DOAS measurements were analyzed. Second, an experimental device for measuring CO2 absorption using lake water was developed, capable of measuring the effect of chloroplasts on the measurements. Then, a simple CO2 sensor was developed using a Raspberry Pi. Observations were made in Baotou in China, and Daigo, Chikusei, and Moriya in Japan using the CO2 sensor. As a result, an improvement to the green space evaluation index was proposed for the land area proposed in our previous study.

Free Research Field

空間情報工学

Academic Significance and Societal Importance of the Research Achievements

多点計測では省電力・小型の機器が必要とされるため，実用性の点でラズべリパイを用いて開発したCO2計測機が有用である.また，DOAS法は数km離れた測点間の計測データを得ることができる点で有利であるが，周辺被覆や太陽光の影響を受ける時間帯があるといった計測上の課題を示した.水槽実験では，水面にスチロール板を浮かべ，周囲を透明プラスチック板で囲い込む工夫をすることで水面直上のCO2濃度の計測可能性を示した。更に，低温対策や晴天時のデータサンプリングおよび緑地指標の改良(陸域向け)を検討した結果，極端地域において安定したデータの収集と緑地効果の評価を行うことができた。以上の点が成果の意義となる.