Schematic of long-term mean AMOC pathways overlapped with sections.
The anatomy of the long-term mean AMOC at northern high latitudes

The AMOC is a key player in climate. However, directly observed long-term mean AMOC state over the past several decades is not available to serve as a reference for historical and future AMOC change, which makes it difficult to know whether model-simulated AMOC changes are reliable. In a recent study authored by Zhang and Thomas, Robust Diagnostic Calculations conducted in a high-resolution global coupled climate model constrained by observed hydrographic climatology provide a holistic picture of the long-term mean AMOC at northern high latitudes over the past several decades.

The mean cross-bathymetry velocity component of numerical-model passive particles within the Deep Western Boundary Current and the trajectories of floats from the Export Pathways campaign (Bower et al. 2009)
How does the Deep Western Boundary Current “leak”?

In a recent study Solodoch et al. researched the dynamics of the leakiness of material from the Deep Western Boundary Current to interior pathways. Through numerical modeling and observational analyses, they discovered that the leakiness is largely concentrated near several hotspots and manifests largely as a steady offshore flow, consistent with inertial separation. This study joins a host of other studies charting and explaining the three dimensional pathways of the AMOC in recent years.

Time series of the Niño-3.4 SST index (°C) in observations (black curves) and ensemble-mean forecasts (colored curves) composited for 10 1-yr El Niño, 5 2-yr El Niño, 4 1-yr La Niña, 8 2-yr La Niña, 4 2-yr La Niña following strong El Niño, and 4 2-yr La Niña following moderate El Niño events during 1954–2015.
Predicting the duration of El Niño and La Niña events with multiyear lead time

A new study by Wu and co-authors shows that the duration of individual ENSO events during 1954-2015 can be predicted up to two years in advance using a suite of multiyear retrospective forecasts conducted with the Community Earth System Model version 1, a climate model that well simulates the statistical and dynamical features of the temporal evolution of ENSO events.

Dye tracer released from the Beaufort Gyre region of the western Artic Ocean indicates freshwater transport through the Canadian Arctic Archipelago into the western Labrador Sea, causing freshening there
Record-high Beaufort Sea freshwater content could alter local and global ocean circulations

The Beaufort Sea increased its freshwater content by 40% over the past two decades. How and where this water will flow into the Atlantic Ocean is important for local and global ocean conditions. Zhang and colleagues simulated ocean circulation and tracked the Beaufort Sea freshwater’s spread during a historical release episode from 1983 to 1995.

High correlations between the mean double-ITCZ and future precipitation changes were identified in the US Southwest and Mediterranean Basin.
Models with corrected double-ITCZ projected drier winters for the US Southwest

Climate models generally project wetter winters for the US Southwest under global warming. Dong et al. discovered a strong relationship between a common model bias with future precipitation changes over this region. More specifically, models with excessive double-ITCZ biases tend to exaggerate the future precipitation increase.

Are long-term changes in mixed layer depth influencing North Pacific marine heatwaves?
Are long-term changes in mixed layer depth influencing North Pacific marine heatwaves?

A new study by Amaya and co-authors in the Special “Explaining Extremes of 2019 from a Climate Perspective” Issue of BAMS now reveals that the record thin ocean mixed layer depth (MLD) that drove a Blob 2.0 in the northeast Pacific Ocean was exacerbated by a multi-decadal shoaling of the mean MLDs in this region since 1980.

Welcome to the US Climate Variability and Predictability Program

Request for public comments on best practices document for commercial Earth observations

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The United States Group on Earth Observations (USGEO) is preparing a document containing best practices for Federal government procurement of commercial Earth observation and geospatial data and services, per the 2019 National Plan for Civil Earth Observations. USGEO is seeking public input from all interested parties (e.g., private sector providers and users, academia, and the public) on best practices to inform the writing of this report. Written input is due June 30, 2021.

Recordings for the Tropical Pacific Observing Needs Workshop now available

TPON Workshop Flyner

Recordings of the plenary sessions are now available online. This include the plenary talks, summary of panel sessions, and opening/closing remarks.

Registration now open for GO-BGC Virtual Workshop

Virtual Workshop on the New Global Ocean Biogeochemistry (GO-BGC) Array

Building a Community of Biogeochemical Float Data Users: The GO-BGC array is a 5-year effort funded by NSF to deploy 500 profiling floats eqiupped with biogeochemical sensors in the world ocean. To inform and engage a broad oceanographic user community, US CLIVAR is teaming up with OCB and GO-BGC leadership to plan a virtual workshop from June 28-30, 2021.