A5016663657- Atmospheric Ozone and Climate
- Climate variability and models
- Ionosphere and magnetosphere dynamics
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Tropical and Extratropical Cyclones Research
- Atmospheric chemistry and aerosols
- Oceanographic and Atmospheric Processes
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Polar Research and Ecology
- Precipitation Measurement and Analysis
- Ocean Acidification Effects and Responses
- High Altitude and Hypoxia
- Aerospace Engineering and Energy Systems
- Hydrological Forecasting Using AI
- Statistical and numerical algorithms
- Marine and coastal ecosystems
- Plant Water Relations and Carbon Dynamics
- GNSS positioning and interference
- Reservoir Engineering and Simulation Methods
- Radiation Dose and Imaging
- Geomagnetism and Paleomagnetism Studies
- Arctic and Antarctic ice dynamics
- Atmospheric aerosols and clouds
Japan Agency for Marine-Earth Science and Technology
2015-2024
Hokkaido University
2023-2024
Pacific International Center for High Technology Research
2019
University of Hawaiʻi at Mānoa
2019
University of Hawaii System
2019
National Centre for Atmospheric Science
2019
University of Oxford
2019
Australian Antarctic Division
2015
University of Tasmania
2015
The University of Tokyo
2003
Abstract. The sixth version of the Model for Interdisciplinary Research on Climate (MIROC), called MIROC6, was cooperatively developed by a Japanese modeling community. In present paper, simulated mean climate, internal climate variability, and sensitivity in MIROC6 are evaluated briefly summarized comparison with previous our model (MIROC5) observations. results show that overall reproducibility variability is better than MIROC5. tropical systems (e.g., summertime precipitation western...
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...
Abstract Gravity wave characteristics in the middle- to high-latitude Southern Hemisphere are analyzed using simulation data over 3 yr from a high-resolution middle-atmosphere general circulation model without any gravity parameterizations. waves have large amplitudes winter and mainly distributed region surrounding polar vortex middle upper stratosphere, while energy is generally weak summer. The distribution not zonally uniform, but it leeward of southern Andes Antarctic Peninsula. Linear...
Abstract The quasi‐biennial oscillation (QBO) of the zonal mean wind is primary mode variability in tropical lower stratosphere. QBO characterized by alternating easterly westerly shear layers that descend down from ∼10 to 100 hPa. also seen stratospheric temperature, water vapor, and ozone affects tropospheric through various teleconnections. We examine here progress simulating Coupled Model Intercomparison Project (CMIP) models, more specifically CMIP3, CMIP5, CMIP6 models. show number...
Using hourly data from a three‐year simulation based on gravity‐wave resolving general circulation model, we have first inferred global view of gravity wave sources and propagation affecting significantly the momentum balance in mesosphere. The meridional cross section fluxes suggests that there are few dominant paths originating subtropics summer middle to high latitudes winter. These waves focused into mesospheric jets their respective seasons, acting effectively decelerate jets....
A high‐resolution middle atmosphere general circulation model (GCM) developed for studying small‐scale atmospheric processes is presented, and the features of are discussed. The GCM has T213 spectral horizontal resolution 256 vertical levels extending from surface to a height 85 km with uniform spacing 300 m. Gravity waves (GWs) spontaneously generated by convection, topography, instability, adjustment in model, reproduces realistic extratropical stratosphere mesosphere. oscillations similar...
Abstract The roles of equatorial trapped waves (EQWs) and internal inertia–gravity in driving the quasi-biennial oscillation (QBO) are investigated using a high-resolution atmospheric general circulation model with T213L256 resolution (60-km horizontal 300-m vertical resolution) integrated for three years. model, which does not use gravity wave drag parameterization, simulates QBO. Although simulated QBO has shorter period than that real atmosphere, its amplitudes structure lower...
Abstract. Teleconnections between the Quasi Biennial Oscillation (QBO) and Northern Hemisphere zonally averaged zonal winds, mean sea level pressure (mslp) tropical precipitation are explored. The standard approach that defines QBO using equatorial winds at a single is compared with empirical orthogonal function characterizes vertical profile of winds. Results interpreted in terms three potential routes influence, referred to as tropical, subtropical polar routes. A novel technique...
A 20-year integration by the nonhydrostatic icosahedral atmospheric model (NICAM) with a 14 km mesh was conducted for first time to obtain climatological mean and diurnal interannual variability of simulated atmosphere. Clouds were explicitly calculated using cloud microphysics scheme without cumulus convection scheme. The simulation performed under intercomparison project-type conditions, except that sea surface temperature nudged toward observed historical values slab ocean model. results...
Abstract Quasi‐biennial oscillations (QBOs) in thirteen atmospheric general circulation models forced with both observed and annually repeating sea surface temperatures (SSTs) are evaluated. In most the QBO period is close to, but shorter than, of 28 months. Amplitudes within ±20 % amplitude at 10 hPa, typically about half that lower altitudes (50 70 hPa). For almost all models, oscillation's profile shows an overall upward shift compared to reanalysis its meridional extent too narrow....
Abstract. The Stratosphere–troposphere Processes And their Role in Climate (SPARC) Quasi-Biennial Oscillation initiative (QBOi) aims to improve the fidelity of tropical stratospheric variability general circulation and Earth system models by conducting coordinated numerical experiments analysis. In equatorial stratosphere, QBO is most conspicuous mode variability. Five have therefore been designed (i) evaluate compare verisimilitude modelled QBOs under present-day conditions, (ii) identify...
Abstract We compare the response of Quasi‐Biennial Oscillation (QBO) to a warming climate in eleven atmosphere general circulation models that performed time‐slice simulations for present‐day, doubled, and quadrupled CO 2 climates. No consistency was found among QBO period response, with decreasing by 8 months some lengthening up 13 others doubled simulations. In simulations, reduction 14 models, whereas several tropical oscillation no longer resembled present‐day QBO, although it could...
Temperature profiles derived from Constellation Observing System for Meteorology, Ionosphere and Climate Global Positioning Radio Occultation satellite constellation data are used to study equatorial gravity wave potential energy associated with waves having vertical wavelengths of less than 7 km their interaction the background quasi‐biennial oscillation (QBO) wind. The binned into grids size 20° in longitude 5° latitude. Results show evidence vertically propagating convectively generated...
Abstract. This paper reports on a project to compare the representation of monthly-mean zonal wind in equatorial stratosphere among major global atmospheric reanalysis data sets. The degree disagreement reanalyses is characterized by standard deviation (SD) and this depends latitude, longitude, height, phase quasi-biennial oscillation (QBO). At each height SD displays prominent maximum, indicating particularly challenging nature problem low-latitude stratosphere. 50–70 hPa geographical...
Abstract. The sixth version of the Model for Interdisciplinary Research on Climate (MIROC), called MIROC6, was cooperatively developed by a Japanese modeling community. In present manuscript, simulated mean climate, internal climate variability, and sensitivity in MIROC6 are evaluated briefly summarized comparison with previous our model (MIROC5) observations. results show that overall reproducibility variability is better than MIROC5. tropical systems (e.g., summertime precipitation western...
Abstract We analyze the stratospheric waves in models participating phase 1 of Stratosphere–troposphere Processes And their Role Climate (SPARC) Quasi‐Biennial Oscillation initiative (QBOi). All have robust Kelvin and mixed Rossby‐gravity wave modes winds temperatures at 50 hPa represent them better than most Coupled Model Intercomparison Project Phase 5 (CMIP5) models. There is still some spread among models, especially concerning waves. attribute variability equatorial QBOi part to varying...
Abstract. This paper reports on a project to compare the representation of semiannual oscillation (SAO) in equatorial stratosphere and lower mesosphere within six major global atmospheric reanalysis datasets with recent satellite Sounding Atmosphere Using Broadband Emission Radiometry (SABER) Microwave Limb Sounder (MLS) observations. All reanalyses have good quasi-biennial (QBO) middle each displays clear SAO centered near stratopause. However, differences among are much more substantial...
Abstract The Quasi‐biennial Oscillation (QBO) dominates the interannual variability of tropical stratosphere and influences other regions atmosphere. high predictability QBO implies that its teleconnections could lead to increased skill seasonal decadal forecasts provided relevant mechanisms are accurately represented in models. Here modelling sampling uncertainties examined using a multi‐model ensemble QBO‐resolving atmospheric general circulation models have carried out set coordinated...
Recovery processes after a major stratospheric sudden warming (SSW) with the formation of an elevated stratopause and strong polar‐night jet are investigated using gravity‐wave‐resolving GCM. The SSW that occurred in GCM bears resemblance to observations January 2006 2009. recovery phase is divided into two stages. In first stage during about five days just SSW, large positive Eliassen‐Palm (E‐P) flux divergence associated growth planetary waves contributes quick eastward wind above 2 hPa...
Abstract Southern Hemisphere extratropical gravity wave activity is examined using simulations from a free-running middle-atmosphere general circulation model called Kanto that contains no parameterizations. The total absolute momentum flux (MF) and its intermittency, diagnosed by the Gini coefficient, are during January July. MF intermittency results calculated agree well with satellite limb superpressure balloon observations. analysis of indicates following results. Nonorographic waves...
Abstract The Quasi‐Biennial Oscillation initiative (QBOi) is a model intercomparison programme that specifically targets simulation of the QBO in current global climate models. Eleven models or versions participated QBOi study have upper boundaries above mesosphere and therefore simulate region where stratopause semiannual oscillation (SAO) dominant mode variability zonal winds tropical stratosphere. Comparisons SAO simulations these are presented here. These show amplitudes phases...
Abstract A multi‐model study is carried out to investigate the ability of models predict evolution quasi‐biennial oscillation (QBO) up 12 months in advance. All are initialised from common reanalysis data, and forecasts run for a set 30 start dates over 15 years. have high skill predicting phase QBO at 20–30 hPa, with slightly more variable results higher lower levels. Other aspects predicted quality, some cases consistently poor. easterlies too weak all 20–50 while westerlies can be either...
Abstract Phase 6 of the Coupled‐Model Intercomparison Project (CMIP6) is first in which a significant number models include well‐resolved stratosphere. Changes equatorial stratospheric variability historical and Shared Socioeconomic Pathways (SSPs) scenario simulations are investigated 10 with realistic quasi‐biennial oscillations (QBO). All project weakening QBO throughout stratosphere for SSP370 SSP585 scenarios 1960 to 2010. The strongest lower stratosphere, ranging from % per decade at...