How have ocean conditions changed in 30 years?
We looked at the ocean conditions from the Bluelink ReANalysis (BRAN2020) experiment, that uses a 10-km resolution (eddy-resolving) ocean model to simulate oceans conditions from 1993 to 2023.
Chamberlain et al. 2021. Next generation of Bluelink ocean reanalysis with multiscale data assimilation: BRAN2020. Earth Syst. Sci. Data, 13, 5663–5688, https://doi.org/10.5194/essd-13-5663-2021
Sea Surface Height
Eddy Field and the Annual Variation in Sea Surface Height
Eddies in the South East Marine ecosystem are large circular ocean currents caused by the southerly East Australian Current. They can last from weeks to months. To show changes in the strength of the eddy field in 1993 and 2023, we calculated the standard deviation in daily Sea Surface Height over each year.
Standard Deviation in BRAN2020 Daily Sea Surface Height 1993 vs 2023
(points are survey sample locations)
Mean monthly Sea Surface Height indicates the warm core (positive) or cold core (negative) eddies. Samples taken on SEFES and SEA-MES voyages in July, 30 years apart, experienced different conditions.
BRAN2020 Monthly Mean Sea Surface Height (m)
1993-July vs 2023-July
BRAN2020 Monthly Mean Sea Surface Height (m)
Selected months of SEFES and SEA-MES surveys
(points are survey sample locations)
| SEFES | SEA-MES |
Mixed Layer Depth
BRAN2020 Monthly Mean Mixed Layer Depth (m)
1993-July vs 2023-July
(points are survey sample locations)
BRAN2020 Monthly Mean Mixed Layer Depth (m)
Selected months of SEFES and SEA-MES surveys (points are survey sample locations)
| SEFES | SEA-MES |
Sea Surface Temperature
BRAN2020 Monthly Mean Sea Surface Temperature (C)
1993-July vs 2023-July
(points are survey sample locations)
BRAN2020 Monthly Mean Sea Surface Temperature (C)
Selected months of SEFES and SEA-MES surveys (points are survey sample locations)
| SEFES | SEA-MES |
Bottom Temperature
BRAN2020 Monthly Mean Bottom Temperature (C)
1993-July vs 2023-July
(points are survey sample locations)
