Phys.org October 14, 2024 Atmospheric rivers (ARs) are key agents in distributing extratropical precipitation and transporting moisture poleward. Climate models suggest an increase in AR activity in the extratropics over the past four decades. However, analyses indicate a poleward shift of ARs during boreal winter in both hemispheres. Researchers at UC Santa Barbara demonstrated that low-frequency sea surface temperature variability in the tropical eastern Pacific exhibited a cooling tendency since 2000 that played a key role in driving global AR shift, mostly over extratropical oceans. This mechanism also operated on interannual timescales, controlled by the El Niño–Southern Oscillation, and was […]
Tag Archives: Rain
Climate change will lead to wetter US winters, modeling study finds
Phys.org September 26, 2024 A team of researchers in the US (University of Illinois Chicago, Argonne National Laboratory, Pacific Northwest National Laboratory, University of Georgia) investigated 21st-century hydroclimate changes over the United States during winter and the sources of projection uncertainty under three emission scenarios using CMIP6 models. Their study revealed a robust intensification of winter precipitation across the US, except in the Southern Great Plains, where changes were very small. By the end of the 21st century, winter precipitation was projected to increase by about 2–5% K−1 over most of the US. The frequency of very wet winters was […]
Raindrops grow with turbulence in clouds: New findings could improve weather and climate models
Phys.org July 25, 2024 A team of researchers in the US (NSF National Center for Atmospheric Research, industry) provided substantial evidence for significant impacts of turbulence on the evolution of cloud droplet size distributions and rain formation by comparing high-resolution observations of cumulus congestus clouds with state-of-the-art large-eddy simulations coupled with a Lagrangian particle-based microphysics scheme. Turbulence causes earlier rain formation and greater rain accumulation compared to simulations with gravitational coalescence only. The observed rain size distribution tail just above cloud base follows a power law scaling that deviates from theoretical scalings considering either a purely gravitation collision kernel or […]
Can East Asian monsoon enhancement induce global cooling?
Phys.org August 2, 2021 The strong erosion in the Himalayas was assumed to be a primary driver of Cenozoic atmospheric CO2 decline and global cooling predominantly through accelerating silicate chemical weathering in the India-Asia collision zone or through effective burial of organic carbon in the nearby Bengal Fan in South Asia. An international team of researchers (China, France) has found that the northward advance of the East Asian monsoon on tectonically inactive subtropical China induced globally significant silicate weathering atmospheric CO2 sink. The organic carbon burial flux is approximately 25% of the contemporary CO2 consumption by silicate weathering. The unusual […]