EGU25-8007, updated on 14 Mar 2025
https://doi.org/10.5194/egusphere-egu25-8007
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Poster | Thursday, 01 May, 14:00–15:45 (CEST), Display time Thursday, 01 May, 08:30–18:00
 
vPoster spot 1, vP1.21
Length of the Day changes and climate signatures- their relations in detected ENSO Events
Małgorzata Wińska1, Justyna Śliwińska-Bronowicz2, Jolanta Nastula2, and Dominika Staniszewska3
Małgorzata Wińska et al.
  • 1Warsaw University of Technology, Faculty of Civil Engineering, The Institute of Roads and Bridges, Warsaw, POLAND (malgorzata.winska@pw.edu.pl)
  • 2Centrum Badań Kosmicznych PAN, Warsaw, POLAND
  • 3Warsaw University of Technology, Faculty of Geodesy and Cartography, Department of Geodesy and Geodetic Astronomy, Warsaw, POLAND

The relationship between the length of day (LOD) and the El Niño-Southern Oscillation (ENSO) has been extensively studied since the 1980s. LOD represents the negative time derivative of UT1-UTC, directly proportional to the Earth Rotation Angle (ERA), a key Earth Orientation Parameter (EOP).

ENSO is a climate phenomenon occurring in the tropical eastern Pacific Ocean that primarily impacts the tropics and subtropics. Extreme ENSO events can lead to severe weather conditions, such as flooding and droughts, across various regions worldwide. ENSO event undergoes a lengthy incubation period, during which the interannual variations in length-of-day (LOD) and atmospheric angular momentum (AAM) are rapidly influenced by the interactions between the ocean and the atmosphere.

The significant characteristics of climate change are the rise of global temperature and sea level, which are driven by ENSO. Interannual oscillations in global mean sea temperature (GMST) and global mean sea level (GMSL) might also impact changes in the Earth’s rotation velocity.

The goal of this study is to explain in more detail connections among the interannual (2-8 years) variations of the LOD, AAM, and different climate indices, like the Southern Oscillation Index SOI, Oceanic Niño Index ONI, GMSL, and GMST. The influence of climate signatures on LOD from January 1976 to December 2024 is assessed using semblance analysis based on continuous wavelet transform. This method evaluates the correlation between climate time series in the time and wavelength domains.

Studying the relationship between LOD, AAM, GMSL, GMST, and ENSO indices enhances our understanding of Earth's dynamic system, improves geophysical models, and increases the precision of applications dependent on accurate timekeeping and Earth rotation measurements.

How to cite: Wińska, M., Śliwińska-Bronowicz, J., Nastula, J., and Staniszewska, D.: Length of the Day changes and climate signatures- their relations in detected ENSO Events, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8007, https://doi.org/10.5194/egusphere-egu25-8007, 2025.