Research reveals how pollution control measures in Europe and the United States over the past 40 years led to significantly decreased anthropogenic aerosols. During the same time period, economic and industrial growth in South and East Asia led to increased anthropogenic aerosols in those regions. The impact of these changes suggests effects on both the frequency of global tropical cyclones (hurricanes and typhoons), as well as a shift in the global wind circulation.. Read More…
GFDL Research Highlights - Atmospheric Processes
The observed trend in Earth’s energy imbalance, a measure of the acceleration of heat uptake by the planet, is a fundamental indicator of perturbations to climate. The study found that it is exceptionally unlikely (< 1% probability) that this observed trend can be explained by natural variations in the climate system alone. Using climate model simulations and by conducting a hierarchy of GFDL CM4/AM4 experiments, the authors estimated the anthropogenic and internal variability contributions to the observed trend during 2001-2020. The study concludes that the satellite record provides clear evidence of a human-influenced climate system. Read More…
February 19th, 2021 - Assessing the influence of COVID-19 on Earth’s radiative balance
The ongoing COVID-19 pandemic led to a worldwide reduction in aerosol emissions. Anecdotal effects on air quality and visibility were widely reported. Less known are the impacts on the planetary energy balance, and by extension, on weather and climate. By separating the impacts from meteorology and emissions with model simulations, the authors found that about one‐third of the clear‐sky anomalies can be attributed to pandemic‐related emission reductions, and the rest to weather variability and long‐term emission trends. Read More…
The authors describe a systematic evaluation of GFDL’s new 50km high-resolution version of the AM4 atmospheric model, for its ability to simulate atmospheric river (AR) characteristics including climatology, variability and future change. This study is relevant for assessing the model’s ability to simulate and predict weather and climate extremes such as flood, drought and extreme winds. Read More…
July 29th, 2019 - Seasonal prediction potential for springtime dustiness in the U.S.
Severe dust storms reduce visibility and cause breathing problems and lung diseases, affecting public health, transportation, and safety. Reliable forecasts for dust storms and overall dustiness are important for hazard preventions and resource planning. Most dust forecast models focus on short, sub-seasonal lead times, i.e., three to six days, and the skill of seasonal prediction is not clear. In this study we examine the potential of seasonal dust prediction in the U.S. using an observation-constrained regression model, with key variables predicted by a seasonal prediction model, GFDL’s Forecast-Oriented Low Ocean Resolution (FLOR). Read More…
December 20th, 2017 - A New Paradigm for Diagnosing Contributions to Model Aerosol Forcing Error
Aerosol radiative forcing and its uncertainty are seen as major challenges that climate models face in reproducing observed temperature records. Climate models, such as those reporting results for the Fourth and Fifth Assessment Reports of the Intergovernmental Panel on Climate Change, exhibit a persistently large range of aerosol radiative forcing, both natural and anthropogenic. For this research, the authors carried out a systematic evaluation of the impact of radiative errors on simulated aerosol radiative effect across the diversity of aerosol distributions resulting from the same experiment, to address a persistent ambiguity in climate sensitivity. Read More…
July 17th, 2017 - Projection of American dustiness in the late 21st century due to climate change
Mineral dust is one of the most abundant atmospheric aerosols by mass. It is lifted to the atmosphere by strong wind from dry and bare surfaces. This study identifies key factors influencing dust activity in the U.S. and uses the projected changes of these influential factors to understand dust activity in the future. Read More…
February 5th, 2015 - Tropical Climate Change Control of the Lower Stratospheric Circulation
Tropical air has less ozone than polar air, even though the tropical stratosphere is where most atmospheric ozone is produced. The Brewer-Dobson circulation is considered key to understanding this apparent contrast. It also brings water vapor, aerosols and other species from the troposphere up into the stratosphere. The strength of the Brewer-Dobson circulation directly affects the thermal structure of the stratosphere and upper troposphere, and impacts the transport and distribution of important climate-influencing constituents including stratospheric water vapor, ozone, and volcanic aerosols. Read More…
The impact of the late 20th century changes of anthropogenic aerosols from local (i.e., South Asia) and remote (i.e., outside South Asia) sources on the South Asian summer monsoon is a rather unexplored topic. It has important implications for strategies to control regional pollution and understand its effect in climate. GFDL scientists investigated the impact of this change in aerosols on the South Asian monsoon. This work provides new insights into the pathway by which global anthropogenic aerosols affect long-term variations of the monsoon hydroclimate, which is still uncertain and largely debated in the scientific community.
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This study investigates the impact of the late 20th century increase of anthropogenic aerosols on the onset of the Indian summer monsoon. Aerosols are likely responsible for the observed earlier onset, resulting in enhanced June precipitation over most of India. This shift is preceded by strong aerosol forcing over the Bay of Bengal and Indochina, mostly attributable to the direct effect, resulting in increased atmospheric stability that inhibits the monsoon migration in May.
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