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.

Recent trends in the warm-season 500-hPa vertical velocity over 1979-2014
Contrasting recent and future changes in the Intertropical Convergence Zone

Under global warming, the ITCZ is projected to shift towards the equator, leading to squeeze in the annual-mean tropical ascent and far-reaching impacts on global circulation. Zhou and coauthors researched the observed and projected ITCZ changes based on a variety of observation and reanalysis datasets and ensemble projections of climate models, and found that the observed ITCZ changes are largely opposite to the projected future changes.

Spatial distribution of two widespread precipitation events that occurred on 8 May 1995 and 13 September 1961 and geometric illustration of the extent of an SHPE on the ground
Understanding the spatial structure of simultaneous heavy precipitation events over the conterminous United States

Najibi, Devineni, and co-authors present a new idea defined as simultaneous heavy precipitation events (SHPEs) to quantify extreme regional precipitation considering the spatial structure of extreme events. Quantifying the characteristics of SHPEs and modeling their footprints can improve the projections of flood risk and understanding of damages to interconnected infrastructure systems.

Welcome to the US Climate Variability and Predictability Program

Workshop on Future US Earth System Reanalysis

Reanalysis Workshop Flyer

The Workshop on Future US Earth System Reanalysis aims at developing a shared scientific, technological, and application vision for the future of the US reanalysis efforts over the next 5-10 years. Registration and abstract submission will open this summer.

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.

Tropical Pacific Observing Needs Workshop: Agenda now available

Tropical Pacific Observing Needs Workshop Flyer

The agenda for the virtual 2021 Tropical Pacific Observing Needs Workshop (May 24-26, 2021) is now available. Do not forget to register by May 17.