Atmospheric rivers are shifting poleward, reshaping global weather patterns

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 […]

Huge waves in the atmosphere dump extreme rain on northern Australia

Phys.org  October 10, 2024 Convectively coupled equatorial waves (CCEWs) can be potential sources of predictability for sub-seasonal to seasonal prediction over northern Australia. Researchers in Australia studied the relationship between these waves and rainfall in northern Australia from 1981 to 2018. They found the waves had a significant impact on rainfall during the southern summer (December–February) and autumn (March–May). When waves combined in certain ways, heavy rain events become even more likely. Due to Australia’s vast landmass and local geography, the impacts of these waves were quite different across the continent. They showed that the activity of the “atmospheric melodies” […]

Tropical storms signaled by atmospheric waves, study finds

Phys.org February 7, 2023 Understanding and prediction of tropical cyclone (TC) activity on the medium range remains challenging. Researchers in the UK found that the pre-existing westward-moving equatorial waves can inform the risk of TC occurrence and intensification, based on a dataset obtained by synchronising objectively identified TCs and equatorial waves in a climate reanalysis. Globally, westward-moving equatorial waves can be precursors to 60–70% of pre-tropical cyclogenesis events, and to >80% of the events with the strongest vorticity, related to the favourable environmental conditions within the pouch of equatorial waves. They also found that when storms are in-phase with westward-moving […]

Better hurricane forecasts from use of infrared satellite measurements of cloudy skies

Phys.org  November 4, 2021 An international team of researchers (USA – University of Wisconsin, NCAR Boulder, UK, Japan, China) surveyed the best practices for the observation and use of satellite infrared sounder and imager measurements demonstrating significant improvement in the forecasting of high-impact weather events such as hurricanes and typhoons. They reviewed development of satellite infrared data assimilation by various practitioners and the solutions they have deployed to better use such data in forecasts. They found that use of these cloud-cleared radiances in data assimilation improves the forecasting of high-impact weather events such as tropical cyclones and is now being applied […]

Deep learning accurately forecasts heat waves, cold spells

EurekAlert  February 4, 2020 Researchers at Rice University have created a deep learning computer system called “capsule neural network”. During training, it examines hundreds of pairs of maps. Each map shows surface temperatures and air pressures at five-kilometers height, and each pair shows those conditions several days apart. The training includes scenarios that produced extreme weather — extended hot and cold spells that can lead to deadly heat waves and winter storms. Once trained, the system was able to examine maps it had not previously seen and make five-day forecasts of extreme weather with 85% accuracy…read more. Open Access TECHNICAL ARTICLE

Closing critical gap in weather forecasting

Science Daily  December 7, 2019 An international team of researchers (USA – NOAA, NASA, George Mason University, University of Florida, SUNY Stony Brook, Canada) reports that the Subseasonal Experiment (SubX) is a multimodel subseasonal prediction [weather conditions 3-to-4 weeks out] experiment designed around operational requirements with the goal of improving subseasonal forecasts. Seven global models have produced 17 years of retrospective (re)forecasts and more than a year of weekly real-time forecasts. The reforecasts and forecasts are archived at the Data Library of the International Research Institute for Climate and Society, Columbia University, providing a comprehensive database for research on subseasonal […]