Project Report

Overseas Fellowship Program Participant: FY2022 First Call Short-Term Program
Yusuke Ochiai (Shinshu University)

I was selected for the ArCS II Overseas Fellowship Program, which allowed me to participate in AsiaFlux 2022 held in Kuching, Malaysia. Presentations at AsiaFlux 2022 included the reports on the results of the latest research measuring the transport of greenhouse gases and energy (heat) between the terrestrial ecosystem and the atmosphere using methods such as the eddy covariance method. I collected information on research related to the Arctic region and made a poster presentation of my own research. In the poster presentation, I presented research results and discussions regarding the effects of land surface changes after forest fires on convective rainfall in the Alaskan boreal forest. The temperature, humidity, and height of the atmospheric boundary layer were approximately reproduced by the model, which resulted in the reproduce of the timings of rainfall onsets on average. At the birch young forest site with small Bowen ratio after the forest fire, the sensitivity analysis of the model to changes in Bowen ratio showed that the frequency of cloud formation and convective rainfall was increasing.

Through discussions with other researchers at poster presentations, I was able to obtain suggestions and advice for my research. For example, I was advised to consider the differences in net radiation between sites when I analyze the sensitivity of the model to changes in Bowen ratio. Following these suggestions, I’m going to summarize the differences in rainfall characteristics before and after the forest fire and the accuracy of convective rainfall prediction in my master’s research.

At AsiaFlux 2022, several presentations of studies on the northern region were made, which allowed me to understand the trends in flux observations in the northern region. In addition, there were reports on changes in energy balance due to alteration by deforestation and drought, or crop phenology, as well as reports showing the relationship between crop variables such as the leaf area index and latent heat flux. I will use these reports as references when considering the effects of vegetation recover after forest fires on changes in latent and sensible heat fluxes in my own research. In addition, there was a report on the relationship between aerosols and rainfall. In my own research, I have seen the events in which cloud formation and rainfall are predicted by the model, but not observed. Using this report as a reference, we will consider the influence of aerosols as a possible cause.

By participating in this program, I was able to have discussions in English with foreign researchers and collect information on the latest research, which was stimulating. Thank you very much for this precious opportunity.