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.

Uncertainty for drifter GMSL and GMSL trend estimates
Can we measure global mean sea level with an array of drifting buoys?

In a recently published Geophysical Research Letters paper, Elipot demonstrates how a new ocean observing system for measuring local and global sea level changes could piggy-back on the existing array of freely drifting buoys. Development and implementation of such sea level measurements could ultimately provide an independent and resilient observational system to infer natural and anthropogenic sea level changes, augmenting the ongoing tide gauge and satellites records.

Visualization of the mass transport carried by particle trajectories
Routes of the upper limb of the Atlantic Meridional Overturning Circulation

In a recent article published in Geophysical Research Letters, researchers investigate the origins of the upper limb of the AMOC at 6°S, from different sections in the global ocean, by determining Lagrangian trajectories and tracing particles backward in time for 2,011 years. One of the key results is that all the routes follow the outer edges of the supergyre of the Southern Hemisphere and converge into the Agulhas region.

Box-plots for the future phase changes (units: days) in the precipitation annual cycle
Why is the seasonal delay of tropical rainfall only evident over land?

A recent study by Song et al. discovered contrasting phase changes of the precipitation annual cycle between land and ocean under global warming, with land delay and ocean advance by examining simulations from 37 CMIP5 models and five large ensembles. They found that the seasonal delay of lands is mainly attributable to the increased effective heat capacity, while there exists a competing mechanism against the impact of increased capacity for the ocean precipitation.

Welcome to the US Climate Variability and Predictability Program

Seeking community input on draft data commercialization white paper

US CLIVAR seeks comments and input from the science community on the draft white paper "Summarizing Weather, Climate, and Earth System Observational Data Sharing Needs for Research and Education."

State estimation and observing system design in support of Arctic Ocean Observing

Arctic Circulation Workshop Blog

In preparation for the US CLIVAR Arctic Circulation Workshop, organizing committee member Patrick Heimbach and his team contribute to post #3: State estimation and observing system design in support of Arctic Ocean Observing.

Tropical Pacific Observing Needs Workshop

Tropical Pacific Observing Needs Workshop Flyer

Registration and abstract submission are now open for the virtual 2021 Tropical Pacific Observing Needs Workshop. Deadline to submit abstracts is March 5, 2021. Registration is free but required in order to attend.