Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate

doi:10.1029/2022JC019587

IOCAS-IR

	Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate
	Tian, Feng 1,2; Zhang, Rong-Hua2,3,4
	2023-07-01
发表期刊	JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
ISSN	2169-9275
卷号	128 期号:7 页码:21
通讯作者	Zhang, Rong-Hua(rzhang@nuist.edu.cn)
摘要	Shortwave penetration (Q(pen)) through the bottom of the oceanic mixed layer (ML) profoundly affects the thermal structure in the upper ocean and consequently contributes to sea surface temperature (SST) change, which has not been adequately understood under global warming. Here, using ensemble earth system model simulations under a high-emissions scenario (SSP5-8.5), we investigate the Q(pen) change and related effects on some oceanic parameters, which are regionally dependent. It is found that globally averaged Q(pen) typically increased by 2.49 +/- 0.83 W m(-2) in the second half of the 21st century, which is comparable to an increase in the net surface heat flux (3.01 +/- 0.31 W m(-2)), corresponding to an increase in SST by 3.07 +/- 0.83 degrees C. Although there exist substantial intermodel uncertainties in the projected chlorophyll change, the shoaled ML contributes the most of the increase in Q(pen) in the global ocean, whereas in the tropical ocean, the reduction in the chlorophyll concentration plays an equivalent role with the mixed layer depth in determining Q(pen) change. The ML heat budget indicates that the enhanced Q(pen) leads to surface cooling through a decrease in the surface net surface heat flux. However, the cooling is compensated for by a warming effect from ocean dynamical change due to more shortwave penetration into the subsurface layer, leading to a small net effect on the ML heat budget. It is suggested that the impact of Q(pen) on the global oceanic ML heat balance needs to be adequately recognized. Plain Language Summary Understanding the mechanism for ocean warming induced by anthropogenic effects (e.g., global warming) is important to study global climate change. The accumulated heat into the ocean (heat gain) mainly consists of heat fluxes at the air-sea interface absorbed with the oceanic mixed layer (ML). Additionally, a small part of shortwave radiation (similar to 20 W m(-2)) can penetrate out of the bottom of the ML and enters the subsurface ocean, which is referred to as Q(pen). As Q(pen) is instantaneously determined by the ML depth and chlorophyll concentration, it also reflects optical characteristics associated with the redistribution of net surface heat flux and biomass. However, the Q(pen) change characteristics and its climatic effect under anthropogenic warming have not been quantified yet. Here, we found that the globally averaged Q(pen) typically increased by 2.49 +/- 0.83 W m(-2) in the second half of the 21st century. Furthermore, the enhanced Q(pen) leads to less heat absorbed within the ML and consequently contributes to surface cooling. Meanwhile, the enhanced Q(pen) makes the subsurface gain more heat, which subsequently warms the ML by ocean dynamical change. Therefore, recognizing the role played by the enhanced penetration is essential to understanding the global oceanic ML heat balance.
DOI	10.1029/2022JC019587
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[42006001] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42000000] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42040100] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB42040103] ; Qingdao postdoctoral application research project ; NFSC[42030410] ; NFSC[LSKJ202202402] ; Startup Foundation for Introducing Talent of NUIST
WOS研究方向	Oceanography
WOS类目	Oceanography
WOS记录号	WOS:001040850000001
出版者	AMER GEOPHYSICAL UNION
WOS关键词	SEA-SURFACE TEMPERATURE ; HYBRID COUPLED MODEL ; EQUATORIAL PACIFIC ; SOLAR-RADIATION ; BIOGEOPHYSICAL FEEDBACK ; INDIAN-OCEAN ; PHYTOPLANKTON ; SIMULATION ; CHLOROPHYLL ; VARIABILITY
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/182675
专题	中国科学院海洋研究所
通讯作者	Zhang, Rong-Hua
作者单位	1.Chinese Acad Sci, Inst Oceanol, CAS Key Lab Ocean Circulat & Waves, Qingdao, Peoples R China 2.Laoshan Lab, Qingdao, Peoples R China 3.Nanjing Univ Informat Sci & Technol, Sch Marine Sci, Nanjing, Peoples R China 4.Univ Chinese Acad Sci, Beijing, Peoples R China
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	Tian, Feng,Zhang, Rong-Hua. Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2023,128(7):21.
APA	Tian, Feng,&Zhang, Rong-Hua.(2023).Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,128(7),21.
MLA	Tian, Feng,et al."Increasing Shortwave Penetration Through the Bottom of the Oceanic Mixed Layer in a Warmer Climate".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 128.7(2023):21.