担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JCLI-D-22-0382.1

Web of Science

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1029/2022GL097997

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/atmos12111377

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/jmsj.2021-060

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JCLI-D-19-0933.1

Web of Science

記述言語：日本語  

DOI： 10.1175/JAMC-D-20-0171.1

Web of Science

DOI： 10.1029/2020GL090675

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/jmsj.2021-060

担当区分：筆頭著者  

DOI： 10.1175/JAS-D-19-0154.1

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1748-9326/ab5da9

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JAS-D-19-0092.1

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JAMC-D-18-0011.1

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JAS-D-17-0355.1

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2017GL076440

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/jmsj.2018-054

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.atmosres.2017.06.021

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10712-017-9429-z

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10712-017-9419-1

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1175/JAMC-D-16-0272.1

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2016JD025827

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2016MS000855

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2016EA000181

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2016JD024753

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/jmsj.2015-032

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.2151/sola.2015-004

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5194/amt-8-1197-2015

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/2014GL062301

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study examines the significance of aerosol serving as cloud condensation nuclei (CCN) in modulating strengths
of tropical maritime convection. Through a Tropical Ocean Global Atmosphere Couple Ocean̶Atmosphere Response
Experiment (TOGA COARE) case study using a cloud-resolving model (the Goddard Cumulus Ensemble Model with
a horizontal mesh interval of 750 m) anda detailedspectral bin microphysical scheme, it is foundthat low aerosol
concentration acts to reduce convection strengths. Over the tropical western Pacific where low-level water vapor is
abundant and a ubiquitous weak stable level exists near 0°C, the low backgroundmaritime aerosol concentration is
conducive for forming cumulus congestus. Sensitivity tests show that the main mechanism of convection damping in a
clean maritime environment is through reduced condensational growth, although the freezing of supercooled water,
cloudtop evaporation, andrain evaporation also contribute to the simulatedeffects. Considering the importance of
congestus in tropical dynamics and the Madden̶Julian oscillation (MJO) lifecycle, we further propose a hypothesis
that aerosol̶cloud̶precipitation interactions in an ultraclean marine environment may serve as a damping mechanism
for tropical convection.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 1784-1800

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 1625-1632

記述言語：英語   掲載種別：研究論文（学術雑誌）  

TRMM-observed mature-stage squall lines during late spring and early summer
in the central USA over a 9-year period are compiled and compared with a case
simulation by the Goddard Cumulus Ensemble (GCE) model with a spectral bin
microphysical scheme. During the quasi-steady state of the simulation, a forward
radiative transfer model calculates TRMM Precipitation Radar (PR) reflectivity
and 85 GHz brightness temperatures from simulated particle size distributions.
Comparisons between model and TRMM observations using radar Contoured
Frequency with Altitude Diagrams (CFADs) and 85 GHz brightness temperature
probability density distributions are performed, in addition to CFADs from a surface
C-band radar for the same case. Radar CFADs comparisons reveal that the model
overestimates sizes of snow/aggregates in the stratiform region.
Three sets of sensitivity tests are carried out in order to improve the simulated
radar reflectivity profiles: increase of aggregates’ density and terminal fall velocity;
changing temperature dependency of collection efficiency between ice-phase
particles, particularly those of the plate-type; and adding a break-up scheme for
large aggregates. While all three approaches mitigate the discrepancies, changing
collection efficiency produces the best match in magnitudes and characteristics
of radar CFADs. In addition, interactions between ice- and water-phase particles
also need to be adjusted in order to have good comparisons in both radar CFADs
and 85 GHz brightness temperature distributions. This study shows that long-term
satellite observations, especially those with multiple sensors, can be very useful in
constraining model microphysics.

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The east Pacific double intertropical convergence zone (ITCZ) in austral fall is investigated with particular
focus on the growing processes of its Southern Hemisphere branch. Satellite measurements from the Tropical
Rainfall Measuring Mission (TRMM) and Quick Scatterometer (QuikSCAT) are analyzed to derive 8-yr
climatology from 2000 to 2007. The earliest sign of the south ITCZ emerges in sea surface temperature (SST)
by January, followed by the gradual development of surface convergence and water vapor. The shallow
cumulus population starts growing to form the south ITCZ in February, a month earlier than vigorous deep
convection is organized into the south ITCZ. The key factors that give rise to the initial SST enhancement or
the southeast Pacific warm band are diagnosed by simple experiments. The experiments are designed to
calculate SST, making use of an ocean mixed layer ‘‘model’’ forced by surface heat fluxes, all of which are
derived from satellite observations. It is found that the shortwave flux absorbed into the ocean mixed layer is
the primary driver of the southeast Pacific warm band. The warm band does not develop in boreal fall because
the shortwave flux is seasonally so small that it is overwhelmed by other negative fluxes, including the latent
heat and longwave fluxes. Clouds offset the net radiative flux by 10–15 W m22, which is large enough for the
warm band to develop in boreal fall if it were not for clouds reflecting shortwave radiation. Interannual
variability of the double ITCZ is also discussed in brief.

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

A long-term observation from the Tropical Rainfall Measuring Mission (TRMM) is analyzed to investigate the Madden-Julian Oscillation (MJO), Kelvin wave, and equatorial Rossby (ER) wave in austral summer seasons. TRMM Precipitation Radar (PR) and Visible/Infrared Scanner (VIRS) measurements are jointly used to clarify convective progression associated with individual modes of the tropical oscillations. Variability in the dynamic and thermodynamic environment involving sea surface temperature (SST), column relative humidity (CRH), and moisture convergence is also examined. A sea surface warming is found to precede the peak MJO convection by ∼ 10 days, while a prior SST increase is not as evident for the Kelvin and ER waves. Moisture convergence and CRH exhibit a horseshoe-like pattern in the composite MJO map, constituted of a pair of off-equatorial maxima and a weak equatorial peak. The Kelvin wave has a moist anomaly on the equator leading the convective peak as theoretically expected, while the moist anomaly also extends poleward without being accompanied by moisture convergence. Moisture convergence leads CRH by a day or two for the Kelvin and ER waves. Moisture convergence is, in contrast, virtually concurrent with CRH for the MJO. The correlation between CRH and deep stratiform coverage is diverse among the three modes of the tropical oscillations. Shallow cumulus and cumulus congestus lead the MJO convective peak by ∼ 1 day, followed by lingering non-precipitating high clouds. ER wave convection is led by moisture convergence but lagged by CRH. The convective progression appears not to proceed in a monotonic way for the ER wave.
A possible mechanism to explain MJO propagation is discussed as suggested by a synthesis of the present findings. The Kelvin wave guides the eastward migration of MJO convection onset over the Indian Ocean. The role of the Kelvin wave in MJO propagation diminishes as the MJO enters the west Pacific with the convective are

記述言語：英語   掲載種別：研究論文（学術雑誌）  

This study discloses detailed Madden–Julian oscillation (MJO) characteristics in the two 30-day integrations
of the global cloud-system-resolving Nonhydrostatic Icosahedral Atmospheric Model (NICAM) using the allseason
real-time multivariateMJO index ofWheeler and Hendon. The model anomaly is derived by excluding
the observed climatology because the simulation is sufficiently realistic.Results showthat theMJOhas a realistic
evolution in amplitude pattern, geographical locations, eastward propagation, and baroclinic- and westwardtilted
structures. In the central IndianOcean, convection develops with the low-level easterlywind anomaly then
matures where the low-level easterly and westerly anomalies meet. Anomalous moisture tilts slightly with
height. In contrast, over the western Pacific, the convection grows with a low-level westerly anomaly.Moisture
fluctuations, leading convection in eastward propagation, tilt clearly westward with height. The frictional
moisture convergence mechanism operates to maintain the MJO. Such success can be attributed to the explicit
representation of the interactions between convection and large-scale circulations. The simulated event, however,
grows faster in phases 2 and 3, and peaks with 30%higher amplitude than that observed, although the 7-km
version shows slight improvement. The fast-growth phases are induced by the fast-growing low-level convergence
in the IndianOcean and the strongly biased ITCZ in the west Pacific when themodel undergoes a spinup.
The simulated OLR has a substantial bias in the tropics. Possible solutions to the deficiencies are discussed.
1. Introduction
The Madden–Julian oscillation (MJO; Madden and
Julian 1971, 1972, 1994) dominates tropospheric variability
in the tropics on time scales of 30–60 days. The
oscillation influences weather and climate variability
substantially in both the tropics (e.g., Yasunari 1979;
Hendon and Liebmann 1990; Lawrence and Webster
2002) and

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Precipitation and high-level cloud (HLC) areas in association with the large-scale circulation over the tropical
Pacific are analyzed for simulations of nineteen Coupled Model Intercomparison Project Phase 3 (CMIP3) models
with observations for 16 years of 1984–1999. The distribution of rainfall and HLC areas are composited around
the geographical center of tropospheric upper-level (200 hPa) divergence (DIV) along Intertropical Convergence
Zone (ITCZ) using monthly anomaly data. Datasets with a finer temporal sampling than monthly means were
not available for the present purposes. The most notable feature is that the horizontal spread of enhanced circulation
and the related rainfall and HLC areas are all underestimated around the DIV center in the models compared
to the observation. Particularly, the underestimation is pronounced in HLC, presumably owing to di‰culties
in the physical processes relevant to the spatial distribution of HLC area. In general, a model with a higher
correlation between the large-scale circulation field and rainfall tends to have a wider spread of HLC area around
the DIV center.

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The Madden–Julian oscillation (MJO), Kelvin wave, and equatorial Rossby (ER) wave—collectively
called intraseasonal oscillations (ISOs)—are investigated using a 25-yr record of outgoing longwave radiation
(OLR) measurements as well as the associated dynamical fields. The ISO modes are detected by
applying bandpass filters to the OLR data in the frequency–wavenumber space. An automated wavetracking
algorithm is applied to each ISO mode so that convection centers accompanied with the ISOs are
traced in space and time in an objective fashion. The identified paths of the individual ISO modes are first
examined and found strongly modulated regionally and seasonally. The dynamical structure is composited
with respect to the convection centers of each ISO mode. A baroclinic mode of the combined Rossby and
Kelvin structure is prominent for the MJO, consistent with existing work. The Kelvin wave exhibits a
low-level wind field resembling the shallow-water solution, while a slight lead of low-level convergence over
convection suggests the impact of frictional boundary layer convergence on Kelvin wave dynamics. A lagged
composite analysis reveals that the MJO is accompanied with a Kelvin wave approaching from the west
preceding the MJO convective maximum in austral summer. MJO activity then peaks as the Kelvin and ER
waves constructively interfere to enhance off-equatorial boundary layer convergence. The MJO leaves a
Kelvin wave emanating to the east once the peak phase is passed. The approaching Kelvin wave prior to the
development of MJO convection is absent in boreal summer and fall. The composite ER wave, loosely
concentrated around the MJO, is nearly stationary throughout. A possible scenario to physically translate
the observed result is also discussed.

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

開催年月日： 2009年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：San Francisco, CA, USA   国名：アメリカ合衆国  

開催年月日： 2009年7月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Montreal, Quebec, Canada   国名：カナダ  

開催年月日： 2009年1月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Phoenix, AZ, USA   国名：アメリカ合衆国  

開催年月日： 2008年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：宮城県仙台市   国名：日本国  

開催年月日： 2008年5月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地： 神奈川県横浜市   国名：日本国  

開催年月日： 2008年1月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催年月日： 2007年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催年月日： 2007年11月

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2007年10月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2007年7月

記述言語：英語   会議種別：口頭発表（一般）  

開催年月日： 2007年5月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：日本国  

開催年月日： 2007年4月

記述言語：英語   会議種別：口頭発表（一般）  

開催年月日： 2006年10月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国