Here are the current Papers & Articles under the research topic Pacific Meridional Mode (PMM) and Pacific Decadal Oscillation (PDO). Click on the title of a paper you are interested in to go straight to the full paper. Papers and articles covering the basics (ideal for learning) are shown in Green.
Revisiting the Pacific Meridional Mode
2018 paper. Abstract:
Numerous studies demonstrated that the Pacific Meridional Mode (PMM) can excite Central Pacific (CP) El Niño-Southern Oscillation (ENSO) events and that the PMM is mostly a stochastic phenomenon associated with mid-latitude atmospheric variability and wind-evaporation-SST feedback. Here we show that CP sea surface temperature (SST) variability exhibits high instantaneous correlations both on interannual (ENSO-related) and decadal (Pacific Decadal Oscillation (PDO)-related) timescales with the PMM. By prescribing an idealized interannual equatorial CP ENSO SST forcing in a partially-coupled atmosphere/slab ocean model we are able to generate a realistic instantaneous PMM response consistent with the observed statistical ENSO/PMM relationship. This means that CP ENSO and the PMM can excite each other respectively on interannual timescales, strongly suggesting that a fast positive feedback exists between the two phenomena. Thus, we argue that they cannot be considered two independent dynamical entities. Additionally, we show that the interannual CP ENSO SST forcing generates atmospheric circulation variability that projects strongly on the Aleutian Low and North Pacific SST anomalies that exhibit the characteristic PDO pattern.
The Pacific Decadal Oscillation less predictable under greenhouse warming
2019 paper. Abstract:
The Pacific Decadal Oscillation (PDO) is the most prominent form of decadal variability over the North Pacific, characterized by its horseshoe-shaped sea surface temperature anomaly pattern1,2. The PDO exerts a substantial influence on marine ecosystems, fisheries and agriculture1,2,3. Through modulating global mean temperature, the phase shift of the PDO at the end of the twentieth century is suggested to be an influential factor in the recent surface warming hiatus4,5. Determining the predictability of the PDO in a warming climate is therefore of great importance⁶. By analysing future climate under different emission scenarios simulated by the Coupled Model Intercomparison Project phase 5 (ref. ⁷), we show that the prediction lead time and the associated amplitude of the PDO decrease sharply under greenhouse warming conditions. This decrease is largely attributable to a warming-induced intensification of oceanic stratification, which accelerates the propagation of Rossby waves, shortening the PDO lifespan and suppressing its amplitude by limiting its growth time. Our results suggest that greenhouse warming will make prediction of the PDO more challenging, with far-reaching ramifications.