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…
Three consecutive dry winters (2015-2017) in southwestern South Africa (SSA) resulted in the Cape Town “Day Zero” drought in early 2018. Combined with management practices and infrastructure shortcomings, the drought caused one of the most serious water crises ever experienced in any heavily populated metropolitan area, with extensive economic impacts. The authors of this study applied a high-resolution (0.5◦×0.5◦) large ensemble, generated from the newly developed Seamless System for Prediction and EArth System Research (SPEAR) global climate model developed at GFDL, to investigate regional hydroclimatic risk. Read More…
The Geophysical Fluid Dynamics Laboratory’s newest Earth System Model, ESM4.1, was developed to study the past, present, and future evolution of the Earth system under scenarios for natural and anthropogenic drivers of earth system change, including greenhouse gases and aerosols. The response of the ocean’s vast carbon and heat reservoirs to accumulating greenhouse gases greatly reduces their atmospheric and terrestrial impacts, but also puts ocean environments and the marine resources they support at risk. This paper describes, evaluates, and discusses the ocean biogeochemical component of ESM4.1. Read More…
The atmospheric model documented in this study, AM4.1, marks the culmination of GFDL’s 4th-generation model development effort that included comprehensive revisions of atmospheric dynamics, physics, and chemistry, and biogeochemical coupling to land and ocean. These efforts were merged into a single atmospheric configuration in support of NOAA’s first coupled carbon-chemistry-climate Earth system model (ESM4.1) with state-of-the-art representation of each component, along with comprehensive interactions between components. The final coupled ESM4.1 configuration is described in a separate manuscript (Dunne et al.). Read More…
The Earth system model documented in this study, ESM4.1, marks the culmination of GFDL’s 4th generation model development effort that included comprehensive revisions of atmospheric dynamics, physics and chemistry, ocean physics, biogeochemistry and ecosystems, sea ice, and land physics, biogeochemistry and ecosystems. These efforts were merged into NOAA’s first coupled carbon-chemistry-climate model with state-of-the-art representation of each, along with comprehensive interactions between components. Read More…
With anthropogenic climate change becoming evident, it is imperative to provide reliable scientific information to society on causes of emerging trends. Sea level pressure (SLP) is a key variable, relevant for impacts and extremes (e.g., steering flows for storms, storm track changes), for which trends and other changes must be monitored and understood. This study explores how the atmospheric circulation may be changing regionally in response to anthropogenic forcing, based on an analysis of sea level pressure trends in observations and models. Read More…
Estuary and coastal ocean forecasts based on predictions of temperature, salinity, currents, and storm surge have been shown to be able to protect lives and property from storm surge, assist search and rescue operations, and protect public health. These forecasts enable predictions of harmful algal blooms and the dispersion of oil spills. Many estuaries are also home to ecologically and economically important ecosystems and fisheries, and forecasts may also be useful for improving the management of fisheries and locating ideal fishing spots. This research demonstrates that temperature and salinity can be skillfully forecast at both the bottom and surface levels of an estuary up to two weeks in advance. 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…
At many weather forecasting centers, different computer weather models are run for different applications. In the U.S., there are separate models for short-range, long-range, seasonal, and hurricane forecasting. Each specialized model is designed by different experts to get the best results. However, having separate models multiplies the effort needed to maintain and upgrade each model, and makes it difficult to move improvements from one model to another. Read More…
Extreme wildfires have increased in Alaska, affecting the economy and public health of an entire region. The authors assessed the influence of anthropogenic activities on extreme fires in Alaska, taking advantage of the modeling capability of GFDL’s Earth System Model (ESM4.1) to simulate the complex interactions between fire, climate, land ecosystem, and human activity. Their findings indicate that a three-fold increased risk of Alaska’s extreme fires during recent decades can be attributed to primarily anthropogenic ignition and, secondarily, climate-induced biofuel abundance. By sorting out controlling factors of wildfires in Alaska, this modeling study improves our understanding of the impact of climate change on wildfires in Alaska, enabling better predictions. Read More…
