A5051506851- Ionosphere and magnetosphere dynamics
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Geophysics and Gravity Measurements
- Atmospheric chemistry and aerosols
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- GNSS positioning and interference
- Meteorological Phenomena and Simulations
- Astro and Planetary Science
- Tropical and Extratropical Cyclones Research
- Oceanographic and Atmospheric Processes
- Atmospheric aerosols and clouds
- Space exploration and regulation
- Planetary Science and Exploration
- Advanced Thermodynamics and Statistical Mechanics
- Statistical Mechanics and Entropy
- Advanced Data Storage Technologies
- Wind and Air Flow Studies
- Rocket and propulsion systems research
- Gas Dynamics and Kinetic Theory
- Magnetic confinement fusion research
- Superconducting Materials and Applications
Goddard Space Flight Center
2023-2025
Heliophysics
2024-2025
United States Naval Research Laboratory
2015-2024
Naval Research Laboratory Space Science Division
2014-2023
Community Coordinated Modeling Center
2023
Clemson University
2023
United States Navy
2016
NSF National Center for Atmospheric Research
2002-2014
NSF NCAR Climate and Global Dynamics Laboratory
2009
Atmospheric and Environmental Research
2003
We have used the Whole Atmosphere Community Climate Model to produce a small (three‐member) ensemble of simulations period 1950–2003. Comparison model results against available observations shows that for most part, is able reproduce well observed trends in zonal mean temperature and ozone, both as regards their magnitude distribution latitude altitude. Calculated water vapor, on other hand, are not at all consistent with from either HALOE satellite instrument or Boulder, Colorado,...
Abstract Recent observational and theoretical studies of the global properties small‐scale atmospheric gravity waves have highlighted effects these on circulation from surface to middle atmosphere. The large‐scale long been treated via parametrizations in both climate weather‐forecasting applications. In parametrizations, key parameters describe distributions gravity‐wave momentum flux, wavelengths frequencies. Until recently, observations could not define required because are small scale...
The Model for Ozone and Related Chemical Tracers, version 3 (MOZART‐3), which represents the chemical physical processes from troposphere through lower mesosphere, was used to evaluate representation of long‐lived tracers ozone using three different meteorological fields. fields are based on (1) Whole Atmosphere Community Climate Model, 1b (WACCM1b), (2) European Centre Medium‐Range Weather Forecasts (ECMWF) operational analysis, (3) a new reanalysis year 2000 ECMWF called EXP471....
Abstract Middle atmospheric general circulation models (GCMs) must employ a parameterization for small-scale gravity waves (GWs). Such parameterizations typically make very simple assumptions about wave sources, such as uniform distribution in space and time or an arbitrarily specified GW source function. The authors present configuration of the Whole Atmosphere Community Climate Model (WACCM) that replaces spectrum with parameterizations. For nonorographic frontal system convective are...
More Than the Sum of Parts The radiative output Sun varies distinctly with 11-year cycle sunspots, although change in energy is small—less than a tenth percent magnitude. Nevertheless, that small variation produces changes sea surface temperatures two or three times as large it should, and mechanism by which this occurs has remained unclear. Meehl et al. (p. 1114 ; see news story Kerr ) employ global, coupled climate models to simulate phenomenon. Two mechanisms appear act conjunction cause...
Abstract Regional extratropical tropospheric variability in the North Pacific and eastern Europe is well correlated with Northern Hemisphere wintertime stratospheric polar vortex both ECMWF reanalysis record Whole Atmosphere Community Climate Model. To explain this correlation, link between vertical Eliassen–Palm flux analyzed. Simple reasoning shows that can deepen or flatten stationary waves, particular its wavenumber-1 -2 components, thus providing a physical explanation for correlation...
Abstract The response of stratospheric climate and circulation to increasing amounts greenhouse gases (GHGs) ozone recovery in the twenty-first century is analyzed simulations 11 chemistry–climate models using near-identical forcings experimental setup. In addition an overall global cooling stratosphere (0.59 ± 0.07 K decade−1 at 10 hPa), causes a warming Southern Hemisphere polar lower summer with enhanced above. rate correlates projected by and, on average, changes from 0.8 0.48 100 hPa as...
A global analysis of convective cloud in the tropical tropopause region (12–17 km) is presented. The based on high‐resolution imagery brightness temperatures from satellites and contemporaneous reanalysis temperatures. coverage by deep convection decreases nearly exponentially with increasing altitude region. Convection found at colder than cold point over ∼0.5% (±0.25%) tropics. rarely penetrates more 1.5 km above tropopause. Large‐scale relationships between indicate that where coldest...
The NCAR Whole Atmosphere Community Climate Model, version 3 (WACCM3), is used to study the atmospheric response from surface lower thermosphere changes in solar and geomagnetic forcing over 11‐year cycle. WACCM3 a general circulation model that incorporates interactive chemistry solves for both neutral ion species. Energy inputs include radiation energetic particles, which vary significantly This paper presents comparison of simulations cycle maximum minimum conditions. Changes composition...
A simulation of the middle atmosphere is presented using a general circulation model (GCM) forced with observed sea surface temperature for period 1950–2000. The GCM extends to lower thermosphere and reproduces realistic dynamical distributions. contains several El Niño La Niña events, which are identified NINO3 index. Composite anomalies relevant meteorological fields obtained by stratifying northern winter season according These have structure vertically propagating planetary waves...
In atmospheric and space environment studies it is key to understand quantify the coupling of regions solar impacts on whole atmosphere system. There thus a need for numerical model that encompasses can self‐consistently simulate dynamic, physical, chemical, radiative, electrodynamic processes are important Sun‐Earth This goal developing National Center Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM). this work, we report development preliminary validation...
Advances in weather and climate research have demonstrated the role of stratosphere Earth system across a wide range temporal spatial scales. Stratospheric ozone loss has been identified as key driver Southern Hemisphere tropospheric circulation trends, affecting ocean currents carbon uptake, sea ice, possibly even Antarctic ice sheets. variability also shown to affect short-term seasonal forecasts, connecting tropics midlatitudes guiding storm-track dynamics. The two-way interactions...
This article describes the implementation of a new source spectrum parameterization for convectively generated gravity waves in Whole Atmosphere Community Climate Model, version 2 (WACCM2). is active tropics and interactive with underlying convection. The wave at each model grid point time step determined based on convective heating depth, tropospheric wind, rate. introduces more realistic spatial temporal distributions activity yields characteristics related to source. We present estimated...
Abstract The simulation of major midwinter stratospheric sudden warmings (SSWs) in six stratosphere-resolving general circulation models (GCMs) is examined. GCMs are compared to a new climatology SSWs, based on the dynamical characteristics events. First, number, type, and temporal distribution SSW events evaluated. Most show lower frequency than climatology, which has mean 6.0 SSWs per decade. Statistical tests that three produce significantly fewer between 1.0 2.6 Second, four...
We present a set of six 20 year experiments made with state‐of‐the‐art chemistry‐climate model that incorporates the atmosphere from surface to lower thermosphere. The response middle 11 solar cycle, its impact on troposphere, and especially role an externally prescribed stratospheric quasi‐biennial oscillation (QBO) is investigated NCAR's Whole Atmosphere Community Climate Model (WACCM3). use either fixed cycle inputs or together QBO phase. annual mean in temperature ozone upper...
The present study compares simulations of the 2009 sudden stratospheric warming (SSW) from four different whole atmosphere models. models included in comparison are Ground‐to‐topside model Atmosphere and Ionosphere for Aeronomy, Hamburg Model Neutral Ionized Atmosphere, Whole Model, Community Climate Extended version (WACCM‐X). focuses on zonal mean, planetary wave, tidal variability middle upper during SSW. constrained lower atmosphere, simulated mean wave is thus similar up to ∼1 hPa (50...
Mesospheric thermal inversions are investigated in a numerical simulation with the Whole Atmosphere Community Climate Model, an upward extension of National Center for Atmospheric Research's Model. The seasonal character, spatial extent, and magnitude inversion layers realistic during winter. In model, occurrence wintertime is direct consequence rapid decay height vertically propagating planetary waves, which induces large temperature perturbations upper mesosphere to maintain hydrostatic...
Between May 2002 and April 2006, many continuous observations of mesopause region temperature horizontal wind, each lasting longer than 24 h (termed full‐diurnal‐cycle observations), were completed at the Colorado State University Na Lidar Facility in Fort Collins, (41°N, 105°W). The combined data set consists 120 binned on a monthly basis, with minimum 7 cycles maximum 18 August. Each was analyzed to deduce mean values tidal period perturbations. After removal signals, are used for study...
Abstract To investigate ionosphere variability during the 2009 sudden stratosphere warming (SSW), we present simulation results that combine Whole Atmosphere Community Climate Model Extended version and thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model (TIME‐GCM). The simulations reveal notable enhancements in both migrating semidiurnal solar ( S W 2) lunar (M 2 ) tides SSW. M amplitudes reach ∼50 m s −1 ∼40 , respectively, zonal wind at E region altitudes....
We present numerical simulations using the Whole Atmosphere Community Climate Model, extended version, constrained below 90 km by a combination of NASA's Modern Era Retrospective Analysis for Research and Applications U.S. Navy's Operational Global Atmospheric Prediction System ‐ Advanced Level Physics High Altitude assimilation products. The period examined is January February 2009, when large stratospheric warming occurred on 24 with anomalous circulation persisting several weeks after...
It is recognized that the resolved tropical wave spectrum can vary considerably among general circulation models (GCMs) and these differences have an important impact on simulated climate. A comprehensive comparison of low-latitude waves presented for December–January–February period using high-frequency data from nine GCMs participating in GCM Reality Intercomparison Project Stratospheric Processes Their Role Climate (GRIPS; SPARC). Quantitative measures wavenumber-frequency structure their...
Recent satellite and radar observations suggest that the semiannual oscillation (SAO) in mesosphere is modulated by stratospheric quasibiennial (QBO). The modulation only apparent during SAO easterly phase, which considerably stronger when QBO winds are westerly than they easterly. We use an equatorial beta-plane model to demonstrate how such a could come about through selective damping of wave spectrum excited deep convection. waves affected most strongly inertia-gravity phase speeds slower...
Abstract It has been known for a long time that the equatorial electrojet varies from day to even when solar and geomagnetic activities are very low. The quiet day‐to‐day variation is considered be due irregular variability of neutral wind, but little about how variable winds drive variability. We employ numerical model introduced by Liu et al. (2013), which takes into account weather changes in lower atmosphere thus can reproduce ionospheric forcing below. simulation run May June 2009....
Abstract The distinctive spatial patterns of the ionosphere's total electron content (TEC) response to solar, seasonal, diurnal, and geomagnetic influences are determined across globe using a new statistical model constructed from 2‐hourly TEC observations 1998 2015. combines representations physical solar EUV photon activity drivers with solar‐modulated sinusoidal parameterizations four seasonal cycles seasonally modulated three diurnal cycles. average absolute residual data‐model...