气候变化领域集成服务门户(CCPortal): Milankovic Forcing in Deep Time

CCPortal

DOI	10.1029/2024PA004861
	Milankovic Forcing in Deep Time
	Zeebe, Richard E.; Lantink, Margriet L.
发表日期	2024
ISSN	2572-4517
EISSN	2572-4525
起始页码	39
结束页码	5
卷号	39 期号:5
英文摘要	Astronomical (or Milankovic) forcing of the Earth system is key to understanding rhythmic climate change on time scales greater than or similar to 10(4) y. Paleoceanographic and paleoclimatological applications concerned with past astronomical forcing rely on astronomical calculations (solutions), which represent the backbone of cyclostratigraphy and astrochronology. Here we present state-of-the-art astronomical solutions over the past 3.5 Gyr. Our goal is to provide tuning targets and templates for interpreting deep-time cyclostratigraphic records and designing external forcing functions in climate models. Our approach yields internally consistent orbital and precession-tilt solutions, including fundamental solar system frequencies, orbital eccentricity and inclination, lunar distance, luni-solar precession rate, Earth's obliquity, and climatic precession. Contrary to expectations, we find that the long eccentricity cycle (LEC) (previously assumed stable and labeled metronome, recent period similar to 405 kyr), can become unstable on long time scales. Our results reveal episodes during which the LEC is very weak or absent and Earth's orbital eccentricity and climate-forcing spectrum are unrecognizable compared to the recent past. For the ratio of eccentricity-to-inclination amplitude modulation (recent individual periods of similar to 2.4 and similar to 1.2 Myr, frequently observable in paleorecords) we find a wide distribution around the recent 2:1 ratio, that is, the system is not restricted to a 2:1 or 1:1 resonance state. Our computations show that Earth's obliquity was lower and its amplitude (variation around the mean) significantly reduced in the past. We therefore predict weaker climate forcing at obliquity frequencies in deep time and a trend toward reduced obliquity power with age in stratigraphic records. For deep-time stratigraphic and modeling applications, the orbital parameters of our 3.5-Gyr integrations are made available at 400-year resolution.
语种	英语
WOS研究方向	Geology ; Oceanography ; Paleontology
WOS类目	Geosciences, Multidisciplinary ; Oceanography ; Paleontology
WOS记录号	WOS:001233799600001
来源期刊	PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/300654
作者单位	University of Hawaii System; University of Hawaii Manoa; University of Wisconsin System; University of Wisconsin Madison
推荐引用方式 GB/T 7714	Zeebe, Richard E.,Lantink, Margriet L.. Milankovic Forcing in Deep Time[J],2024,39(5).
APA	Zeebe, Richard E.,&Lantink, Margriet L..(2024).Milankovic Forcing in Deep Time.PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY,39(5).
MLA	Zeebe, Richard E.,et al."Milankovic Forcing in Deep Time".PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 39.5(2024).