Abstract
The Madden-Julian Oscillation (MJO) is the leading mode of intraseasonal climate variability, having profound impacts on a wide range of weather and climate phenomena. Here, we use a wavelet-based spectral Principal Component Analysis (wsPCA) to evaluate the skill of 20 state-of-the-art CMIP6 models in capturing the magnitude and dynamics of the MJO. By construction, wsPCA has the ability to focus on desired frequencies and capture each propagative physical mode with one principal component (PC). We show that the MJO contribution to the total intraseasonal climate variability is substantially underestimated in most CMIP6 models. The joint distribution of the modulus and angular frequency of the wavelet PC series associated with MJO is used to rank models relatively to the observations through the Wasserstein distance. Using Hovmöller phase-longitude diagrams, we also show that precipitation variability associated with MJO is underestimated in most CMIP6 models for the Amazonia, Southwest Africa, and Maritime Continent.
| Original language | English |
|---|---|
| Article number | e2020GL092244 |
| Journal | Geophysical Research Letters |
| Volume | 48 |
| Issue number | 12 |
| DOIs | |
| State | Published - Jun 28 2021 |
| Externally published | Yes |
Funding
The authors acknowledge support provided by the National Science Foundation (NSF) under the TRIPODS + X program (Grant DMS‐1839336) and the EAGER program (Grant ECCS‐1839441), as well as by NASA’s Global Precipitation Measurement program (Grant 80NSSC19K0684). Upon request, the code that supports the findings of this paper can be provided by the corresponding authors. The authors acknowledge the FAIR data policy.
Keywords
- CMIP6
- MJO
- PCA
- spectral
- wavelet