Fire hazards can have catastrophic effects on human society and ecosystems, posing a pronounced threat to public health, food security, infrastructure, assets, and natural resources. Over the past few decades, fire events have been increasing in size and severity worldwide. Atmospheric vapor pressure deficit (VPD) measures the difference between saturation vapor pressure and actual vapor pressure, and its variability is closely related to fire activity in the Western U.S. Read More…
GFDL Research Highlights
Atmospheric rivers (ARs) are long and narrow atmospheric weather systems that carry large amounts of water vapor. ARs typically cover areas larger than 300,000 km2 and accompany significant precipitation changes over the U.S. They present both societal risks, such as flooding and extreme precipitation, and benefits – including contributions to water resources and snowpack. Using GFDL’s SPEAR prediction system, the authors pinpoint three distinct sources of seasonal predictability of winter AR frequency. They also found that wintertime AR and precipitation predictability over North America are driven by the same sources. Read More…
February 10th, 2025 - What Are the Finger-like Clouds in the Hurricane Inner-core Region?
The inner core region of hurricanes harbors complex dynamical features, including small-scale clouds characterized by finger-like appearances pointing toward the hurricane eye. These features have been frequently observed in intense hurricanes. However, many basic aspects of these features remain unknown, particularly regarding what controls their occurrence, location, and spatial distribution. The authors conducted a numerical simulation with a very fine (about 100 m) horizontal grid spacing to investigate the nature of these features. Their results reveal a mechanism which explains several key characteristics of these features. Read More…
Assessing the impact of anthropogenic climate changes on tropical cyclone activity is of notable scientific and public interest. Since 1980, human-made aerosol emissions have decreased in Europe and the U.S. but increased in China and India. This study used SPEAR, a climate model developed at GFDL, to explore how regional aerosol changes affect global tropical cyclones. Read More…
Despite being the second-smallest ocean on Earth, the Southern Ocean plays an outsized role in absorbing heat and carbon generated from human activities, accounting for over 40% of the planet’s oceanic carbon uptake and 67%–98% of the global ocean heat uptake. As the climate warms, however, changes to the Southern Ocean’s circulation – caused by stronger, more southerly winds and increased meltwater from the Antarctic ice sheet – could affect its heat and carbon absorption abilities, which in turn would have significant consequences for global temperatures and sea level rise. Read More…
The occurrence of extreme weather events, such as heatwaves, droughts, and floods, has increased substantially since the pre-industrial period, but this trend has large regional variations. An important driver of the regional climate variability is the zonally asymmetric atmospheric circulation, or stationary waves, forced by the zonal asymmetries in the Earth’s surface such as the land-sea thermal contrast and elevated terrain (e.g., hills and mountains). Read More…
The Northwest Atlantic Shelf, from the coasts of North Carolina and Virginia to the Gulf of Maine to Newfoundland, has warmed more rapidly than almost any other part of the ocean in the last two decades. This warming has had severe impacts on marine ecosystems and coastal communities. Understanding the drivers of this warming and predicting whether it will continue is thus important for mitigating or adapting to future impacts. Read More…
August 13th, 2024 - Anthropogenic effects on tropical cyclones near Western Europe
Tropical Cyclones (TC) hitting Western Europe are not as rare as one might think. Approximately 10% of Atlantic TCs have made landfall in Europe in the past four decades, about one European landfall per year. Understanding and projecting TC frequency change is especially challenging in certain coastal regions with lower TC activity yet high exposure, and a relatively short duration of reliable observed records – such as Western Europe. Read More…
Large, damaging wildfires are becoming a common occurrence in Canada, the Pacific Northwest, and California. Five of the most destructive wildfire seasons of the last half-century have occurred in the past seven years. These wildfires can cause significant air pollution: burning biomass emits hundreds of reactive gases, including nitrogen oxides, carbon monoxide, ammonia, and an array of volatile organic compounds. Read More…
Nitrogen fertilizer usage and cultivation-induced biological nitrogen fixation help feed nearly half the global population. These practices, in addition to fossil fuel burning for energy production, have increased reactive nitrogen losses to the environment, causing a cascade of negative impacts on the ecosystem and human health. Nitrogen emissions to the atmosphere have contributed to acid rain, air pollution, stratospheric ozone depletion, and the radiative forcing underlying climate change. Nitrogen fluxes from lands have also impaired freshwater quality and contributed to coastal eutrophication, hypoxia, and harmful algal blooms, putting aquatic resources and the communities that depend upon them at risk. Read More…