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…
GFDL Research Highlights
The occurrence of exceptionally high sea levels can cause severe coastal flooding and inundation, threatening lives and infrastructure in the coastal regions. High sea level also alters the coastal environment, moving barrier islands and cutting channels through them, impacting forests and crops, inundating the coastline with salt water, and damaging habitats essential to support wildlife. Read More…
November 17th, 2023 - Anthropogenic forcing changes coastal tropical cyclone frequency
Anthropogenic activities have been affecting our climate since the industrial revolution. The effect of anthropogenic climate change on tropical cyclones (TCs) is of particular concern because of their catastrophic damage at landfall and their relatively frequent occurrence compared to other natural hazards. However, attributing a regionally observed change in tropical cyclone frequency (TCF) to anthropogenic climate change is notoriously challenging for two main reasons. First, climate internal variability can considerably modulate regional TC activities. Second, reliable TC observations are only available since the satellite era, and therefore, not long enough to separate the potential effect of anthropogenic climate change from climate internal variability. Read More…
September 5th, 2023 - Coherent mechanistic patterns of tropical land hydroclimate change
Accurate predictions of future changes in hydroclimate over land, in particular the magnitude and frequency of extreme heat, extreme rainfall, and droughts are of paramount importance for society. Gaps in our process-level understanding of land-atmosphere interactions remain, in particular with respect to the connection between changes in different types of extremes; and the connection between changes in local land-atmosphere interactions with the global-scale response of the hydrological cycle to climate forcings. The authors introduce a novel method that preserves the mechanistic local, daily-mean time scale understanding while substantially reducing the dimensionality of the global, time-varying problem in order to provide an integrated, big-picture perspective. Read More…
Tropical forests buffer climate change impacts by acting as a major sink for anthropogenic carbon emissions, which is essential to slowing down the buildup of atmospheric CO2. However, the response of tropical forests to more frequent weather extremes and long-recovery disturbances like fires remains uncertain. Analyses of field data and ecological theory raise concerns about the possibility of the Amazon crossing a tipping point, leading to catastrophic tropical forest loss. In contrast, climate models consistently project an enhanced tropical sink. Read More…
Hurricanes, also known as tropical cyclones (TC), are the costliest weather disasters in the U.S. and accurate hurricane track and intensity forecasts are crucial for early preparation. High-resolution models (approximately 3 km grid spacing or finer) covering a large domain are emerging as powerful tools for hurricane prediction. However, while the use of high resolution helps improve hurricane intensity prediction, it can also make the model more prone to develop errors in the prediction of steering flow and hurricane tracks – due to the possible impact of prevalent small-scale features resolved by the model. This study suggests that regulating small-scale convection activity in a high-resolution model can significantly improve hurricane track predictions at days 4 and 5. 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…
Extreme precipitation is among the most destructive natural disasters. Simulating changes in regional extreme precipitation remains challenging, partially limited by the horizontal resolution in climate models. For this study, the authors used an ensemble of high-resolution (25-km) global climate model simulations to study extreme precipitation over the Northeastern United States, where extremes have increased rapidly since the mid-1990s. Read More…
One of the most puzzling observed climate events in recent years was the dramatic decline in Antarctic Sea ice extent (SIE) in late 2016. It remains unclear to what extent this low sea ice extent can be attributed to changing ocean conditions. This SIE retreat persisted for several years after 2016, thus becoming a multiyear shift. 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…