Heatwaves are impactful extreme climatic events that occur in the atmosphere and even the oceans. Recent research indicates that marine heatwaves (MHWs) will become more frequent and intense under global warming conditions. This situation will likely push marine organisms and ecosystems to their resilience limits and possibly beyond, which could cause irreversible changes and damage.

Scientists with the Institute of Atmospheric Physics at the Chinese Academy of Sciences (IAP CAS) recently published a study in Advances in Atmospheric Sciences that breaks down a real-time updated high-resolution (0.25°) global MHW dataset, which includes accessibility, content, characteristics, and potential applications of MHWs.

"MHWs have occurred more frequently in most ocean regions in the past two decades." said Dr. ZHENG Fei, corresponding author of the study and professor with the International Center for Climate and Environmental Sciences at IAP CAS.

To begin their research, the team first analyzed the MHW dataset's reliability. They demonstrated that the MHW dataset can accurately detect abnormal warm water events, and it can be used to analyze different attributes of MHWs. Further analysis of the dataset shows a linear increased frequency of MHWs in most ocean regions of the world as well as significant interdecadal changes. Researchers also studied the effects of MHWs on the world's four most productive fishing grounds, or regions.

The linear trend of global MHWs frequency from 1982 to 2020. (Image by ZHENG Fei)

"Analyses of the world's four major fishing grounds also display that three of the fishing grounds had significant MHW growth trends in recent decades." remarked Dr. ZHENG.

In contrast, the growth of MHWs in the Peru Fishing Grounds was not significant, indicating that regional ocean upwelling may slow down the production of MHWs.

Prof. ZHENG suggest that climatologists can use this dataset as a base to study the seasonal and decadal changes in extreme ocean events, as well as explore the effects of global warming on the oceans' surface layers during the last 40 years. Additionally, scientists can use the real-time updated dataset to study the ecological impacts of MHWs, support fisheries, and conduct other relevant studies.

Citation: Zhang, X. J., F. Zheng, J. Zhu, and X.-R. Chen, 2022: Observed frequent occurrences of marine heatwaves in most ocean regions during the last two decades. Adv. Atmos. Sci., https://doi.org/10.1007/s00376-022-1291-3.

Media contact: Ms. LIN Zheng, jennylin@mail.iap.ac.cn