A5000712197- Climate variability and models
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Geology and Paleoclimatology Research
- Meteorological Phenomena and Simulations
- Atmospheric chemistry and aerosols
- Tropical and Extratropical Cyclones Research
- Ocean Acidification Effects and Responses
- Geophysics and Gravity Measurements
- Archaeology and Natural History
- Oceanographic and Atmospheric Processes
- Seismic Imaging and Inversion Techniques
- Distributed and Parallel Computing Systems
- Advanced Data Storage Technologies
- Geological and Geophysical Studies
- Complex Systems and Time Series Analysis
- Clinical Nutrition and Gastroenterology
- Geological and Tectonic Studies in Latin America
- Botany, Ecology, and Taxonomy Studies
- Plant Water Relations and Carbon Dynamics
- Methane Hydrates and Related Phenomena
- Ionosphere and magnetosphere dynamics
- Marine and fisheries research
- Groundwater and Isotope Geochemistry
- Botany and Geology in Latin America and Caribbean
NSF National Center for Atmospheric Research
2019-2024
George Mason University
2023
Johnson Space Center
2023
Auburn University
2023
Cooperative Institute for Research in Environmental Sciences
2018-2020
NOAA Earth System Research Laboratory
2018-2020
University of Colorado Boulder
2018-2020
Indiana University
2020
Colorado State University
2013-2019
University of Washington
2002-2011
We describe the main differences in simulations of stratospheric climate and variability by models within fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above stratopause relatively fine vertical resolution (high‐top), those below (low‐top). Although simulation mean two ensembles is similar, low‐top ensemble has very weak on daily interannual time scales. The frequency major sudden warming events strongly underestimated with less than half observed reanalysis data...
Abstract The arid subtropics are situated at the edges of tropical belt, where subsidence in Hadley cells suppresses precipitation. Any meridional shift these edge latitudes could have significant impacts on surface climate. Recent studies investigated past and future changes belt width found discrepancies rates expansion estimated with different metrics between climate models reanalyses. Here, CMIP5 simulations four modern reanalyses analyzed using an ensemble objective to reexamine if such...
Abstract There is mounting evidence that the width of tropics has increased over last few decades, but there are large differences in reported expansion rates. This is, likely, part due to wide variety metrics have been used define tropical width. Here we perform a systematic investigation into relationship among nine zonal-mean using preindustrial control and abrupt quadrupling CO 2 simulations from suite coupled climate models. It shown latitudes edge Hadley cell, midlatitude eddy-driven...
ABSTRACT To explore the various couplings across space and time between ecosystems in a consistent manner, atmospheric modeling is moving away from fractured limited-scale strategy of past toward unification range scales inherent Earth system. This paper describes forward-looking Multi-Scale Infrastructure for Chemistry Aerosols (MUSICA), which intended to become next-generation community infrastructure research involving chemistry aerosols. MUSICA will be developed collaboratively by...
Abstract Prediction systems to enable Earth system predictability research on the subseasonal time scale have been developed with Community System Model, version 2 (CESM2) using two configurations that differ in their atmospheric components. One uses Atmosphere 6 (CAM6) its top near 40 km, referred as CESM2(CAM6). The other employs Whole Climate (WACCM6) whose extends ∼140 and it includes fully interactive tropospheric stratospheric chemistry [CESM2(WACCM6)]. Both are utilized carry out...
Abstract Subseasonal prediction fills the gap between weather forecasts and seasonal outlooks. There is evidence that predictability on subseasonal timescales comes from a combination of atmosphere, land, ocean initial conditions. Predictability land often attributed to slowly varying changes in soil moisture snowpack, while sources such as El Niño Southern Oscillation. Here we use set reforecast experiments with CESM2 quantify respective roles conditions skill over land. These reveal...
Our research at Union Oil Platform EVA, off Huntington Beach,
Abstract. Observational and modeling studies suggest that Earth's tropical belt has widened over the late 20th century will continue to widen throughout 21st century. Yet, estimates of tropical-width variations differ significantly across studies. This uncertainty, an unknown degree, is partly due large variety methods used in width. Here, for eight commonly metrics width are implemented Tropical-width Diagnostics (TropD) code package MATLAB programming language. To consolidate various...
Abstract The width of the tropical Hadley circulation (HC) has garnered intense interest in recent decades, owing to emerging evidence for its expansion observations and models anticipated impacts on surface climate descending branches. To better clarify causes widening, this work generalizes zonal mean HC regional level by defining meridional overturning cells (RC) using horizontally divergent wind. edges RC are more closely connected hydroclimate than traditional metrics (such as sea...
Abstract Subseasonal weather prediction can reduce economic disruption and loss of life, especially during “windows opportunity” when noteworthy events in the Earth system are followed by characteristic patterns. Sudden stratospheric warmings (SSWs), breakdowns winter polar vortex, one such event. They often precede warm temperatures Northern Canada cold, stormy throughout Europe United States - including most recent SSW on January 5th, 2021. Here we assess drivers surface weeks following...
Abstract. Specified dynamics schemes are ubiquitous modeling tools for isolating the roles of and transport on chemical weather climate. They typically constrain circulation a chemistry–climate model to in reanalysis product through linear relaxation. However, recent studies suggest that these create divergence climate meridional between models do not accurately reproduce trends circulation. In this study we perform systematic assessment specified scheme Community Earth System Model version...
Simulating whole atmosphere dynamics, chemistry, and physics is computationally expensive. It can require high vertical resolution throughout the middle upper atmosphere, as well a comprehensive chemistry aerosol scheme coupled to radiation physics. An unintentional outcome of development one most sophisticated hence expensive model configurations that it often excludes broad community users with limited computational resources. Here, we analyze two Community Earth System Model Version 2,...
An expansion of the tropical belt has been extensively reported in observations, reanalyses, and climate model simulations, but there is a great deal uncertainty estimates rate widening as different diagnostics give wide range results. This study critically examines robust for width to explore their seasonality, interannual variability, multidecadal trends. The based on latitudes maximum tropospheric dry bulk static stability, measuring difference potential temperature between tropopause...
Abstract Over the past 15 years, numerous studies have suggested that sinking branches of Earth’s Hadley circulation and associated subtropical dry zones shifted poleward over late twentieth century early twenty-first century. Early estimates this tropical widening from satellite observations reanalyses varied 0.25° to 3° latitude per decade, while global climate models show at lower end observed range. In 2016, two working groups, U.S. Climate Variability Predictability (CLIVAR) group on...
Simulating whole atmosphere dynamics, chemistry, and physics is computationally expensive. It can require high vertical resolution throughout the middle upper atmosphere, as well a comprehensive chemistry aerosol scheme coupled to radiation physics. An unintentional outcome of development one most sophisticated hence expensive model configurations that it often excludes broad community users with limited computational resources. Here, we analyze two Community Earth System Model Version 2,...
Abstract Numerous studies have concluded that historical Hadley cell expansion simulated in reanalyses is much larger than the future predicted by climate model simulations. Is too weak models, or are trends spuriously large? This study shows mean meridional circulation generally does not conserve mass. The mass imbalance projects onto edge latitudes modifying both and anomalous circulation. In correcting for imbalance, majority of early‐generation hemispheres revised to be smaller...
Abstract. Model simulations of future climates predict a poleward expansion subtropical arid at the edges Earth's tropical belt, which would have significant environmental and societal impacts. This may be related to shift Hadley cell edges, where subsidence stabilizes atmosphere suppresses precipitation. Understanding primary drivers is hampered by myriad forcing agents in most model projections climate. While many previous studies examined response idealized models simplified climate...
Abstract Earth’s arid subtropics are situated at the edges of tropical belt, which encircles planet along equator and covers half its surface area. The climate belt is strongly influenced by Hadley cells, with their subsidence easterly trade winds both sustaining aridity belt’s edges. understanding past, present, future climates contingent on dynamics influencing this region. An important but unanswered question how realistically models reproduce mean state belt. This study augments existing...
NASA's future Artemis missions to the Moon seek explore areas around Lunar South Pole. Though humans have previously set foot on lunar surface, proposed region provides unique and challenging environments that require insight investigation prior arrival. Several teams throughout agency are performing this site mission planning, design, analysis support like Human Landing System (HLS), surface mobility, habitation elements, scientific exploration. The NASA Exploration Systems Simulation...
[1] Using a new reanalysis data set, the seasonal cycle of midlatitude tropospheric static stability is examined. Dry and moist measures are analyzed as function latitude, longitude, season. It shown that in both Northern (NH) Southern Hemispheres (SH), dry averaged over midlatitudes maximizes December–February. Examining spatial structure changes indicates difference between hemispheres due to behavior land, which its winter. Ocean surfaces have qualitatively similar cycles hemispheres....
Abstract. Specified dynamics (SD) schemes relax the circulation in climate models toward a reference meteorology to simulate historical variability. These simulations are widely used isolate dynamical contributions variability and trends trace gas species. However, it is not clear if stratospheric overturning properly reproduced by SD schemes. This study assesses numerous modeling choices Community Earth System Model (CESM) Whole Atmosphere Chemistry Climate (WACCM) determine set of best...
This paper provides a framework for evaluating creativity in co-creative systems: those that involve computer programs collaborating with human users on creative tasks. We situate systems within broader context of computational and explain the unique qualities these systems. present four main questions can guide evaluation Who is creativity, what being evaluated, when does occur how performed. These provide comparing existing evaluate we apply them to examples art, humor, games robotics....
Abstract Variations in the width and strength of Hadley cells are associated with many radiative, thermodynamic, dynamical forcings. The physical mechanisms driving these responses remain unclear, part because interactive nature eddy‐mean flow adjustment. Here, a modeling framework is developed which separates mean time‐mean eddy gray radiation general circulation model simple representations ocean heat transport ozone. In absence eddies, moist convection weak numerical damping, cell...
Abstract. Several analyses of satellite-based ozone measurements have reported that lower stratospheric has declined since the late 1990s. In contrast to this, was found be increasing in specified dynamics (SD) simulations from version 4 Whole Atmosphere Community Climate Model (WACCM-SD) where model nudged using reanalysis wind/temperature fields. This paper demonstrates standard configuration WACCM-SD fails reproduce underlying tropical upwelling changes present fields used drive model....