海洋再解析データを用いたアカイカ好適生息域モデルの構築とその利用 五十嵐, 弘道; 淡路, 敏之; 石川, 洋一 ...
JAMSTEC Report of Research and Development,
2014, Volume:
18
Journal Article
Open access
文部科学省「気候変動適応研究推進プログラム」(RECCA: Research Program on Climate Change ...Adaptation)の研究課題「気候変動に伴う水産資源・海況変動予測技術の革新と実利用化」プロジェクトで開発した,海洋再解析データを用いたアカイカ好適生息域モデルにより,夏季における北太平洋日付変更線付近のアカイカ漁場において日々変動するアカイカ好適生息域を精度よく推定することが可能となった.さらに,この成果を,インターネットと衛星通信を介して配信するウェブシステムを構築し,操業中のイカ釣り漁船にリアルタイム配信する実証試験を行った.その結果,イカ釣り漁船が,本プロジェクトで作成したアカイカ漁海況情報を利用することにより,漁場探査の効率化や燃油消費ひいては二酸化炭素排出量削減につながったことが,聞き取り調査から明らかとなり,本プロジェクトの成果が実利用上も有益であることが示された.
Data assimilation has been recently considered as a key and essential component of understanding of oceanic phenomena, development of parameterization process in numerical ocean modeling, mapping out ...of observation strategies and forecasting of ocean state. Variational adjoint method is introduced as one of the data assimilation method in this introductory review. The basic concept of the variational adjoint method is to combine observations via variational method (estimation theory or Lagrange's multiplier method) with a dynamical model. The method is applied to a parameter estimation in a simple model of an unsteady Ekman flow in physical oceanography. Recent developments of the method are also introduced briefly.
Reflection of internal waves at the interface between the mixed layer and a stratified fluid is experimentally investigated. Reflection coefficients of the internal waves and transmission ...coefficients of interfacial waves are obtained through experiments, where the interfacial waves propagate along the interface. In order to reveal the energy budget of the two kinds of waves, the reflection and transmission coefficients are adopted in consideration of wave dissipation. Where a ratio of the frequencies of the interfacial and internal waves is 1/2, 1 or 2 with the same horizontal wavenumber, the over-reflection takes place (i.e. reflection coefficient >1), while under the same condition the transmission coefficient of the interfacial wave is less than unity. Therefore, it is estimated that the energy source of the over-reflection of the internal wave is the interfacial wave. When the two kinds of waves have the identical frequencies and are in phase, over-reflection also takes place. On the other hand, the interfacial wave over-transmits the energy (i.e. transmission coefficient >1), where the phases of the two kinds of waves are inverse to each other.