The fraction of 1- to 96-day variability in 250-hPa geopotential height anomalies that is associated with the MJO, according to cross-spectral analysis
The Quasi-Biennial Oscillation modulates teleconnections of the Madden-Julian Oscillation

Research by Toms et al. estimates how much impact the QBO has on the global teleconnection signature of the MJO. The authors use a spectral decomposition approach to quantify the relationships between the MJO and upper-tropospheric geopotential separately for each season of the year and for westerly and easterly QBO phases. Similar to previous studies, the results suggest that the MJO is related to upper-tropospheric geopotential anomalies across the globe. The novel contribution of the results lies in the analysis of the impacts of the QBO.

Array locations and simple schematic of water mass overturning transports
First-ever daily time series of the strength of the abyssal MOC cell in the South Atlantic

Kersalé, Meinen, and coauthors investigate the MOC flows at the southern end of the South Atlantic Ocean to evaluate the variability of the oceanic circulation across 34.5°S in the South Atlantic at all depths and at a daily frequency. This research highlights the first-ever daily quantification of the time-varying strength of the abyssal cell at 34.5°S, for which prior studies had only produced once-a-decade "snapshot" ship section estimates.

Composites of NOAA Climate Prediction Center precipitation in mm day-1 broken down by MJO phase for active MJO days for the November 2015 - April 2016 El Niño event.
US precipitation modulated by MJO-ENSO teleconnection interference

Subseasonal to seasonal climate forecasts in the US depends heavily on atmospheric and oceanic conditions in the tropical Indian and Pacific Ocean regions. While ENSO dominates seasonal predictability, the primary source of global predictability on subseasonal timescales is the MJO. To understand how ENSO and MJO interact, the authors isolated both MJO and ENSO signals and found that depending on the simultaneous location of the MJO convection and the background state of ENSO, the two signals can either enhance or mask each other.

Saildrone: Adaptively sampling the marine environment
Saildrone: Adaptively sampling the marine environment

To improve atmospheric and oceanographic monitoring, a new type of autonomous marine vehicle, the Saildrone, has been developed and deployed in over 40 cruises from which data are publicly available. Coupled with data from other sources such as satellites, Saildrone measurements could be useful for future algorithm and numerical model improvements, particularly at the fine spatial scale and in complex and previously data-sparse ocean regions.

 Sources of uncertainty in climate projections and their relative importance for different variables and regions.
Large Ensemble model simulations help to better quantify sources of uncertainty in climate projections

A new collection of single model initial-condition large ensembles (SMILEs) can test statistical assumptions with a cleaner separation between sources of uncertainty in climate projections. In particular, the potential bias at regional scales or for variables with a lot of internal variability can be greatly reduced.

Time of emergence of the anthropogenic signal in storm-related extreme sea level at New York in the GFDL CM4 simulations.
Elevated storm surge differs in origin along the US East and Gulf Coasts

Yin and coauthors use the new GFDL CM4 and CM4HR models to consider a series of climate change experiments under the CMIP6 protocol to study characteristics of extreme sea level events and their future evolution in a fully coupled weather, climate, sea level, and storm surge modeling system. They found that even in the absence of global warming, the Gulf Coast is most vulnerable to hurricane-induced storm surge.

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Tropical Pacific Observing Needs Workshop

Tropical Pacific Observing Needs Workshop

Save the date for the Tropical Pacific Observing Needs Workshop, May 24-26, 2021. This workshop will gather community input on the types of Tropical Pacific ocean and atmosphere observations needed to advance understanding of poorly observed subgrid-scale processes and how such observations could be leveraged to improve satellite retrievals, data assimilation, and parameterized processes in climate, forecast, and biogeochemical models.

Arctic Circulation Workshop Blog

Arctic Circulation Workshop

In preparation for the Workshop on Observing, Modeling, and Understanding the Circulation of the Arctic Ocean and Sub-Arctic Seas, the organizing committee initiated an online topical community discussion to share perspectives in advance of the workshop.