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.
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.
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.
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.
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.
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.
