semidiurnal
/ˌsɛmidaɪˈɜrnəl/
adjective
- Occurring twice a day, especially in reference to tides or astronomical cycles.
- Scientists study semidiurnal variations in the ocean to predict flooding.
- Coastal areas with semidiurnal patterns experience two high tides and two low tides daily.
- The semidiurnal tides rise and fall twice every 24 hours.