A5053264978- Climate variability and models
- Meteorological Phenomena and Simulations
- Atmospheric and Environmental Gas Dynamics
- Oceanographic and Atmospheric Processes
- Arctic and Antarctic ice dynamics
- Tropical and Extratropical Cyclones Research
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Atmospheric Ozone and Climate
- Climate Change and Environmental Impact
- Atmospheric chemistry and aerosols
- demographic modeling and climate adaptation
- Distributed and Parallel Computing Systems
- Hydrology and Drought Analysis
- Social Media in Health Education
- Seismology and Earthquake Studies
- Species Distribution and Climate Change
- Atmospheric aerosols and clouds
- Wind and Air Flow Studies
- Physical Activity and Health
- Mobile Health and mHealth Applications
- Scientific Computing and Data Management
- Environmental and Social Impact Assessments
- Telemedicine and Telehealth Implementation
Climate and Global Dynamics Laboratory
2010-2024
NSF National Center for Atmospheric Research
2015-2024
Apple (United States)
2024
Nexen (Canada)
2018
TransCanada (Canada)
2014
University of Illinois Urbana-Champaign
2001
An overview of the Community Earth System Model Version 2 (CESM2) is provided, including a discussion challenges encountered during its development and how they were addressed. In addition, an evaluation pair CESM2 long preindustrial control historical ensemble simulations presented. These performed using nominal 1° horizontal resolution configuration coupled model with both "low-top" (40 km, limited chemistry) "high-top" (130 comprehensive versions atmospheric component. contains many...
Abstract While internal climate variability is known to affect projections, its influence often underappreciated and confused with model error. Why? In general, modeling centers contribute a small number of realizations international assessments [e.g., phase 5 the Coupled Model Intercomparison Project (CMIP5)]. As result, error are difficult, at times impossible, disentangle. response, Community Earth System (CESM) community designed CESM Large Ensemble (CESM-LE) explicit goal enabling...
Uncertainty in future climate change presents a key challenge for adaptation planning. In this study, uncertainty arising from internal variability is investigated using new 40-member ensemble conducted with the National Center Atmospheric Research Community Climate System Model Version 3 (CCSM3) under SRES A1B greenhouse gas and ozone recovery forcing scenarios during 2000–2060. The contribution of intrinsic atmospheric to total further examined 10,000-year control integration model...
Abstract The Pacific decadal oscillation (PDO), the dominant year-round pattern of monthly North sea surface temperature (SST) variability, is an important target ongoing research within meteorological and climate dynamics communities central to work many geologists, ecologists, natural resource managers, social scientists. Research over last 15 years has led emerging consensus: PDO not a single phenomenon, but instead result combination different physical processes, including both remote...
Abstract The Whole Atmosphere Community Climate Model version 6 (WACCM6) is a major update of the whole atmosphere modeling capability in Earth System (CESM), featuring enhanced physical, chemical and aerosol parameterizations. This work describes WACCM6 some important features model. can reproduce many modes variability trends middle atmosphere, including quasi‐biennial oscillation, stratospheric sudden warmings, evolution Southern Hemisphere springtime ozone depletion over twentieth...
This study examines the tropical linkages to interdecadal climate fluctuations over North Pacific during boreal winter through a comprehensive and physically based analysis of wide variety observational datasets spanning twentieth century. Simple difference maps between epochs high sea level pressure (1900–24 1947–76) low (1925–46 1977–97) are presented for numerous variables throughout Indo-Pacific region, including rainfall, cloudiness, surface temperature (SST), pressure. The results...
Abstract This study highlights the relative importance of internally generated versus externally forced climate trends over next 50 yr (2010–60) at local and regional scales North America in two global coupled model ensembles. Both ensembles contain large numbers integrations (17 40): each which is subject to identical anthropogenic radiative forcing (e.g., greenhouse gas increase) but begins from a slightly different initial atmospheric state. Thus, diversity projected within ensemble due...
Abstract The spatial patterns, time history, and seasonality of African rainfall trends since 1950 are found to be deducible from the atmosphere’s response known variations global sea surface temperatures (SSTs). robustness oceanic impact is confirmed through diagnosis 80 separate 50-yr climate simulations across a suite atmospheric general circulation models. Drying over Sahel during boreal summer shown warming South Atlantic relative North SST, with ensuing anomalous interhemispheric SST...
Diagnostics combining atmospheric reanalysis and station-based temperature data for 1950–2003 indicate that European heat waves can be associated with the occurrence of two specific summertime circulation regimes. Evidence is presented during record warm summer 2003, excitation these regimes was significantly favored by anomalous tropical Atlantic heating related to wetter-than-average conditions in both Caribbean basin Sahel. Given persistence climate anomalies, their seasonality,...
This study compares the global distribution of 20th century SST and marine air temperature trends from a wide variety data sets including un‐interpolated archives as well globally‐complete reconstructions. Apart eastern equatorial Pacific, all datasets show consistency in their statistically significant trends, with warming everywhere except far northwestern Atlantic; largest are found middle latitudes both hemispheres. Two reconstructions exhibit cooling over disagreement which this region....
Abstract This study presents an overview of the El Niño–Southern Oscillation (ENSO) phenomenon and Pacific decadal variability (PDV) simulated in a multicentury preindustrial control integration NCAR Community Climate System Model version 4 (CCSM4) at nominal 1° latitude–longitude resolution. Several aspects ENSO are improved CCSM4 compared to its predecessor CCSM3, including lengthened period (3–6 yr), larger range amplitude frequency events, longer duration La Niña Niño. However, overall...
Abstract This study elucidates the physical mechanisms underlying internal and forced components of winter surface air temperature (SAT) trends over North America during past 50 years (1963–2012) using a combined observational modeling framework. The framework consists 30 simulations with Community Earth System Model (CESM) at 1° latitude–longitude resolution, each which is subject to an identical scenario historical radiative forcing but starts from slightly different atmospheric state....
Abstract The U.S. Climate Variability and Predictability (CLIVAR) working group on drought recently initiated a series of global climate model simulations forced with idealized SST anomaly patterns, designed to address number uncertainties regarding the impact forcing role land–atmosphere feedbacks regional drought. runs were carried out five different atmospheric general circulation models (AGCMs) one coupled atmosphere–ocean in which was continuously nudged imposed forcing. This paper...
This paper describes the Stratospheric Aerosol Geoengineering Large Ensemble (GLENS) project, which promotes use of a unique model dataset, performed with Community Earth System Model, Whole Atmosphere Climate Model as its atmospheric component [CESM1(WACCM)], to investigate global and regional impacts geoengineering. The simulations were designed achieve multiple simultaneous climate goals, by strategically placing sulfur injections at four different locations in stratosphere, unlike many...
Application of random sampling techniques to composite differences between 18 El Niño and 14 La Niña events observed since 1920 reveals considerable uncertainty in both the pattern amplitude Northern Hemisphere extratropical winter sea level pressure (SLP) response ENSO. While SLP responses over North Pacific America are robust variability, their magnitudes can vary by a factor 2; other regions, such as Arctic, Atlantic, Europe less patterns, amplitudes, statistical significance. The...
Abstract Internal variability in the climate system gives rise to large uncertainty projections of future climate. The due internal can be estimated from ensembles change simulations which experiment setup is same one ensemble member next but for small perturbations initial atmospheric state. However, are invariably computationally expensive and susceptible model bias. Here authors outline an alternative approach assessing role based on a simple analytic statistics unforced variability....
This study highlights the expected range of projected winter air temperature and precipitation trends over next 30–50 years due to unpredictable fluctuations North Atlantic Oscillation (NAO) superimposed upon forced anthropogenic climate change. The findings are based on a 40-member initial-condition ensemble simulations covering period 1920–2100 conducted with Community Earth System Model version 1 (CESM1) at 1° spatial resolution. magnitude (and in some regions, even sign) Europe, Russia...
Abstract. A community diagnostics and performance metrics tool for the evaluation of Earth system models (ESMs) has been developed that allows routine comparison single or multiple models, either against predecessor versions observations. The priority effort so far to target specific scientific themes focusing on selected essential climate variables (ECVs), a range known systematic biases common ESMs, such as coupled tropical variability, monsoons, Southern Ocean processes, continental dry...
Abstract The evolving roles of anthropogenic aerosols (AER) and greenhouse gases (GHG) in driving large-scale patterns precipitation SST trends during 1920–2080 are studied using a new set “all-but-one-forcing” initial-condition large ensembles (LEs) with the Community Earth System Model version 1 (CESM1), which complement original “all-forcing” CESM1 LE (ALL). number ensemble members (15–20) each LEs enables regional impacts AER GHG to be isolated from noise model’s internal variability....
Recently, there has been substantial effort to understand the fundamental characteristics of warm ocean temperature extremes-known as marine heatwaves (MHWs). However, MHW research primarily focused on surface signature these events. While MHWs (SMHW) can have dramatic impacts ecosystems, extreme warming along seafloor also significant biological outcomes. In this study, we use a high-resolution (~8 km) reanalysis broadly assess bottom (BMHW) continental shelves North America. We find that...
The wintertime atmospheric circulation responses to observed patterns of North Atlantic sea surface temperature and ice cover trends in recent decades are studied by means experiments with an general model. Here the relationship between forced dominant pattern internally generated variability is focused on. total response partioned into a portion that projects onto leading mode internal (the indirect response) residual from projection direct response). This empirical decomposition yields...