Winter atmospheric rivers (ARs) are crucial for water supply and extreme weather events in both the western (WUS) and eastern United States (EUS), yet their long-term trends and interactions remain unclear. The authors address this by analyzing multiple observational AR datasets spanning the past four decades. They identified contrasting yet interrelated trends in AR frequency, intensity, and associated mean precipitation, and explain these trends based on large-scale atmospheric and oceanic variability in the Pacific. Their findings offer a unified explanation for the observed AR trends and carry important implications for mitigating risks related to AR-induced extreme events in both densely populated coastal regions. Read More…
GFDL Research Highlights - Atmospheric Processes
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…
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…
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…
May 28th, 2024 - Cloud radiative effects associated with daily weather regimes
This research Investigates the effect of high-impact storms on Earth’s radiation budget, in order to better constrain climate models and improve weather and climate forecasts. Using detailed satellite observations and reanalysis data, the author categorized daily weather patterns into different types and measured the cloud radiative effects (CRE) associated with each type. The weather patterns included non-precipitation days, drizzle, wet non-storm days, and storm days, encompassing events like atmospheric rivers, tropical storms, and mesoscale convective systems. Read More…
Under global warming, changes in the location and structure of the deep convection in the tropics have profound consequences for tropical climate. The tropics are characterized by the ubiquitous presence of high ice clouds formed by detrainment from precipitating deep convection. The bulk of these clouds are so-called anvil clouds in extensive formations that shield the convective centers. These can persist for several hours after the decay of active convection and they carry low to moderate ice loads. Read More…
Projections of future nutrient limitation and primary production have implications for fisheries management. The authors used GFDL’s Earth system model, ESM4.1, to explore climate-driven changes in the deposition of dust and iron from the atmosphere to the ocean under a range of climate change scenarios, in an attempt to understand where the “fish food” is going to be and why. Read More…
Greenhouse gas emissions from human activities trap heat (radiative forcing) and cause global warming. This warming is amplified or diminished by feedbacks in the climate system. We had limited direct observations of global greenhouse gas forcing and feedbacks, despite the fact that they are the primary causes of climate change. While it has long been known that resolving the thermal spectrum at different wavelengths can help us to better separate the signals due to forcings and feedbacks, observing this has been elusive because of irregular, uncalibrated, or limited measurements. However, the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua Satellite has recently provided such data (2003-2021). Read More…
Bubbles bursting at the ocean surface are an important source of sea spray aerosols. They contribute to atmospheric aerosols and play a crucial role in radiative and cloud processes. Uncertainties related to the large range of scales involved, and the complexity of the processes, leads to open questions about the dependencies on wind speed, ocean wave properties and water temperature. Read More…
The Indo-Gangetic Plain (IGP), stretching from Pakistan to Bangladesh across Northern India, and home to over 800 million people, experiences among the most elevated concentrations of fine particulate matter (PM2.5) in the world. High local anthropogenic emissions associated with waste and crop residue burning, transportation, industry, and power generation are the primary cause for the poor air quality in the region. Unlike other major population centers in Europe, the United States, and China, air pollution has been worsening in the IGP over the last two decades. Exposure to such high levels of air pollution are estimated to reduce average life expectancy by nearly a decade. Read More…