3:00 PM - 3:15 PM
[MIS16-05] High-spatiotemporal-resolution hindcast simulation for reproducing coral reef environments in Sekisei Lagoon, Okinawa, Japan
Keywords:hindcast simulation, ocean circulation model, downscaling
Scleractinian corals provide high-resolution (monthly to weekly) climate and environmental records on the shallow-water tropical and subtropical ocean regions. The environmental parameters, such as temperature and salinity, are extracted from the coral skeleton as environmental proxies, such as skeletal δ18O, Sr/Ca and Mg/Ca. However, to convert the proxies to certain environmental parameters, the environment proxies should be calibrated with observation data. Because the proxies usually do not follow theoretical values due to biological activities, so-called vital-effect. Therefore, to convert the proxies to environmental parameters and to extend proxies extracted from the coral core to long-term environmental data, the environmental data on where coral cores are collected is required. However, available on-site past environmental data is very limited.
Recently some global/regional ocean analysis/reanalysis products, such as Global HYCOM (https://www.hycom.org/), JCOPE2M (Miyazawa et al., 2017; 2019), and JCOPE-T DA (Varlamov et al., 2015) are released. The latest Global HYCOM is 3 hourly products and available from 1994 to the present. The JCOPE2M is daily products and available from 1992 to present. The JCOPE-T DA is hourly products and available from 2018 to present. The analysis/reanalysis products might be a good option for extending the availability of environmental data. However, the products are not enough resolution for extract environments inside our target area, Sekisei lagoon, since the resolutions of the Global HYCOM, JCOPE2M and JCOPE-T DA are 1/12° (~9 km), 1/12° (~9 km) and 1/36° (~3 km), respectively.
For overcoming the problems, we conducted downscaling from global/regional products to the Sekisei lagoon area by multi-nested approach by using an ocean circulation model based on the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System (Warner et al., 2010). A YAEYAMA1 is the coarsest grid which is 1.5 km grid resolution and covering the East-coast of Taiwan to Miyako Island. The YAEYAMA1 was downscaled from Global HYCOM between 1994 and 2018, and JCOPE-T DA between 2018 and present. The YAEYAMA1 is downscaled to YAEYAMA2 domain which is 300 m resolution and covering the entire Ishigaki Island and Iriomote Island, then that is finally downscaled to YAEYAMA3 domain which is 100 m resolution and covering Sekisei lagoon area by offline one-way nesting. Since the Global HYCOM products do not include tide, the tidal forcing by TPXO9-atlas global tidal solution (Egbert and Svetlana, 2002) was added to the boundaries produced by Global HYCOM products. Atmospheric forcing datasets are used Dynamical Regional Downscaling Using the JRA-55 Reanalysis (DSJRA-55; Kayaba et al., 2016) from 1994 to 2003, and Japan Meteorological Agency’s Meso-Scale Model Grid Point Value (MSM-GPV) from 2004 to the present. By using this multi-nested model, we can obtain a long-term (1994 to present) high-spatiotemporal-resolution (hourly, 100-m grid resolution) dataset of temperature, salinity and water velocity around the Sekisei lagoon area.
Recently some global/regional ocean analysis/reanalysis products, such as Global HYCOM (https://www.hycom.org/), JCOPE2M (Miyazawa et al., 2017; 2019), and JCOPE-T DA (Varlamov et al., 2015) are released. The latest Global HYCOM is 3 hourly products and available from 1994 to the present. The JCOPE2M is daily products and available from 1992 to present. The JCOPE-T DA is hourly products and available from 2018 to present. The analysis/reanalysis products might be a good option for extending the availability of environmental data. However, the products are not enough resolution for extract environments inside our target area, Sekisei lagoon, since the resolutions of the Global HYCOM, JCOPE2M and JCOPE-T DA are 1/12° (~9 km), 1/12° (~9 km) and 1/36° (~3 km), respectively.
For overcoming the problems, we conducted downscaling from global/regional products to the Sekisei lagoon area by multi-nested approach by using an ocean circulation model based on the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System (Warner et al., 2010). A YAEYAMA1 is the coarsest grid which is 1.5 km grid resolution and covering the East-coast of Taiwan to Miyako Island. The YAEYAMA1 was downscaled from Global HYCOM between 1994 and 2018, and JCOPE-T DA between 2018 and present. The YAEYAMA1 is downscaled to YAEYAMA2 domain which is 300 m resolution and covering the entire Ishigaki Island and Iriomote Island, then that is finally downscaled to YAEYAMA3 domain which is 100 m resolution and covering Sekisei lagoon area by offline one-way nesting. Since the Global HYCOM products do not include tide, the tidal forcing by TPXO9-atlas global tidal solution (Egbert and Svetlana, 2002) was added to the boundaries produced by Global HYCOM products. Atmospheric forcing datasets are used Dynamical Regional Downscaling Using the JRA-55 Reanalysis (DSJRA-55; Kayaba et al., 2016) from 1994 to 2003, and Japan Meteorological Agency’s Meso-Scale Model Grid Point Value (MSM-GPV) from 2004 to the present. By using this multi-nested model, we can obtain a long-term (1994 to present) high-spatiotemporal-resolution (hourly, 100-m grid resolution) dataset of temperature, salinity and water velocity around the Sekisei lagoon area.