A5001660177- Climate variability and models
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Meteorological Phenomena and Simulations
- Geophysics and Gravity Measurements
- Geological and Geophysical Studies
- Ocean Waves and Remote Sensing
- Atmospheric Ozone and Climate
- Ionosphere and magnetosphere dynamics
- Atmospheric aerosols and clouds
- Solar and Space Plasma Dynamics
- Marine and coastal ecosystems
- Atmospheric chemistry and aerosols
- GNSS positioning and interference
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Coastal and Marine Management
- Spacecraft and Cryogenic Technologies
- Maritime Navigation and Safety
- Underwater Acoustics Research
- Aeolian processes and effects
- Precipitation Measurement and Analysis
- Island Studies and Pacific Affairs
- Maritime Transport Emissions and Efficiency
- Ocean Acidification Effects and Responses
Japan Agency for Marine-Earth Science and Technology
2016-2025
University of Hawaiʻi at Mānoa
2019
University of Hawaii System
2019
NSF National Center for Atmospheric Research
2019
Pacific International Center for High Technology Research
2019
Okayama University
2008
Tokyo University of Marine Science and Technology
1995-2003
Kyushu University
1989
An international field campaign aiming at atmospheric and oceanic processes associated with the Madden–Julian oscillation (MJO) was conducted in around tropical Indian Ocean during October 2011–March 2012. The objective of to collect observations urgently needed expedite progress understanding key MJO, focusing on its convective initiation but also including propagation maturation, ultimately improve skills numerical simulation prediction MJO. Primary targets included interaction deep...
Turbulent and radiative exchanges of heat between the ocean atmosphere (hereafter fluxes), surface wind stress, state variables used to estimate them, are Essential Ocean Variables (EOVs) Climate (ECVs) influencing weather climate. This paper describes an observational strategy for producing 3-hourly, 25-km (and aspirational goal hourly at 10-km) flux stress fields over global, ice-free with breakthrough 1-day random uncertainty 15 W m-2 a bias less than 5 m-2. At present this accuracy...
Abstract [1] The Madden-Julian Oscillation (MJO) is the dominant mode of intraseasonal variability in tropical atmosphere. This study examines evolution hydrologic regime from before onset MJO (pre-onset period) to period, using deuterated water vapor (HDO) measurements Tropospheric Emission Spectrometer (TES) and ground-based stations. Ground-based observations reveal a clear transition between high HDO/H2O isotope ratios during pre-onset period repeated abrupt decreases ratio associated...
Abstract The upper-air sounding network for Dynamics of the Madden–Julian Oscillation (DYNAMO) has provided an unprecedented set observations studying MJO over Indian Ocean, where coupling this oscillation with deep convection first occurs. With 72 rawinsonde sites and dropsonde data from 13 aircraft missions, covers tropics eastern Africa to western Pacific. In total nearly 26 000 soundings were collected during experiment’s 6-month extended observing period (from October 2011 March 2012)....
Abstract Global cloud/cloud system-resolving models are perceived to perform well in the prediction of Madden–Julian Oscillation (MJO), a huge eastward -propagating atmospheric pulse that dominates intraseasonal variation tropics and affects entire globe. However, owing model complexity, detailed analysis is limited by computational power. Here we carry out simulation series using recently developed supercomputer, which enables statistical evaluation MJO skill costly new-generation manner...
A polarization lidar was continuously operated aboard the research vessel Mirai in tropical western Pacific over three northern winters: at 2.0°N, 138.0°E during November and December 2001; 138.5°E 2002; 7.5°N, 134.0°E 2004 January 2005. Intensive radiosonde soundings were made from 3‐h intervals all campaigns. The mechanisms that underlie observed variations cirrus tropopause layer (TTL) are discussed viewpoint of large‐scale dynamics transport. During 2001 campaign, region cold, but TTL...
Abstract This study analyzes data obtained by intensive observation during a pilot field campaign of the Years Maritime Continent Project (Pre-YMC) to investigate diurnal cycle precipitation in western coastal area Sumatra Island. The period (November–December 2015) is found have number similarities with statistical behavior as revealed previous studies, such afternoon over land, nighttime offshore migration zone, and dependency on Madden–Julian oscillation (MJO) phase. Composite analyses...
Abstract Years of the Maritime Continent (YMC) is a multiyear international program with participants from over 15 countries. Its overarching goal to expedite progress toward improving understanding and prediction local oceanic atmospheric multiscale variability Indo‐Pacific (MC) its global impacts. YMC motivated by unique role MC in both weather climate systems, our lack key processes governing this role, persistent systematic biases errors numerical model output for region. builds...
Abstract Recent studies using TOGA COARE data have found that extremely dry air from middle‐latitude waves frequently intrudes into the equatorial troposphere over western Pacific. Using sounding taken during COARE, magnitude of advection water vapour for one event is calculated, and it estimated lime atmosphere to recover moist conditions was ∼ 10‐20 days. From drying frequency these events, proposed intrusions must be a major contributor tropospheric moisture budget region making difficult...
The Mirai Indian Ocean cruise for the Study of Madden-Julian oscillation (MJO)-convection Onset (MISMO) was a field experiment that took place in central equatorial during October–December 2006, using research vessel Mirai, moored buoy array, and landbased sites at Maldive Islands. aim MISMO to capture atmospheric oceanic features when convection MJO initiated. This article describes details as well some selected early results. Intensive observations Doppler radar, radiosonde, surface...
Abstract The role of air–sea interaction in the diurnal variations convective activity during suppressed and developing stages an intraseasonal event is analyzed using situ observations from Mirai Indian Ocean cruise for Study Madden–Julian oscillation (MJO)-convection Onset (MISMO) experiment. For whole period, convection shows a clear average cycle with primary maximum early morning secondary one afternoon. Episodes large sea surface temperature (SST) are observed because warm layer (DWL)...
The authors investigated diurnal convection peak characteristics over the eastern Indian Ocean off island of Sumatra during different phases Madden-Julian oscillation (MJO). During MJO 2 to 3 (P2 and P3) defined by Wheeler Hendon (2004), prominent variation in was observed satellites when moderate low-level westerly winds were dominant Ocean. peaks evening, while migrations toward early morning. By using Global Positioning System around western region offshore Sumatra, a significant...
Abstract We investigate the influence of background wind regime on interannual variability in equatorial Kelvin waves (including both freely propagating ones and convectively coupled ones) upper troposphere lower stratosphere using ERA5 re-analysis data. focus number wave cases as a function westerly that controls propagation, given by zonal index (ZWI) eastern Pacific is measure strength branch Walker circulation western hemisphere. The ZWI correlates well with sea surface temperature...
Recent studies using data from the Tropical Ocean and Global Atmosphere program's Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) have shown that synoptic-scale areas of extremely dry air can occur in troposphere over equatorial western Pacific. These layers modify convective activity vertical profile radiation clear air. At present time there is some disagreement as to dynamic mechanism responsible for these events a number their characteristics are relatively unknown. In this...
Atmospheric soundings using the Vaisala RS92 radiosonde were intensively conducted during field experiment MISMO (Mirai Indian Ocean cruise for Study of MJO-convection Onset) in central and eastern equatorial from October to December 2006. By comparing relative humidity data with that Meteolabor Snow White (SW) chilled-mirror dew/frost-point hygrometers launched on same ship around local noon time, dry bias was found increase significantly height. In addition, it also revealed had a clear...
Abstract This study examines the variability in surface meteorological parameters and air‐sea heat fluxes due to cold pools emanating from cumulus convective systems observed over tropical Indian Ocean November 2011. In particular, this focuses on that are spatially smaller than mesoscale a southeasterly trade wind environment. Composite analyses of convectively active periods show an increase sensible flux by 15–20 W m −2 is primarily attributed difference between air temperature sea latent...
Precipitable water vapor (PWV) was measured using a shipborne Global Positioning System (GPS) during two month cruise in the equatorial Indian Ocean. More than 300 profiles were also observed by radiosondes released from ship experiment. GPS atmospheric delay and PWV estimated compared to radiosonde observations. The GPS‐PWV is good agreement with (RS‐PWV) an rms error of 2.27 mm mean difference less 1 nighttime. In daytime, dry bias RS‐PWV becomes 3.63 mm. Thus under way open ocean...
Abstract Tropospheric moisture is a key factor controlling the global climate and its variability. For instance, moistening of lower troposphere necessary to trigger convective phase Madden–Julian oscillation (MJO). However, relative importance processes this has yet be quantified. Among these processes, by shallow convection still debated. The authors use high-frequency observations humidity from Research Vessel (R/V) Mirai that was located in Indian Ocean ITCZ during Cooperative Experiment...
Interactions between the convective activity and atmospheric thermodynamic structures are analyzed utilizing upper-air rawinsonde observations obtained by R/V Mirai, Kaiyo, Natsushima, of Japan Agency for Marine-Earth Science Technology (JAMSTEC) over western tropical Pacific Ocean, those three GEWEX Asian Monsoon Experiment (GAME) stations: Chiang Mai, Non Khai, Ubon Ratchathani. Special emphases placed on understanding correlation convection in relation to recent findings tri-modal cloud...
The future changes in the Madden-Julian Oscillation (MJO) and its extratropical teleconnection East Asia during boreal winter are examined by analyzing 12 climate models with good simulation skills of MJO convective signal Coupled Model Intercomparison Project phase 3 (CMIP3). convection increases over western to central Indian Ocean (IO) under warming seven (MJO-plus models). However, it decreases other five (MJO-minus wintertime sea surface temperature (SST) exhibits more El Niño-like...
This study examined the impact of an active phase Madden–Julian Oscillation (MJO) on a torrential rain event that occurred western coast Sumatra Island 12 December 2015, using surface meteorological observations, radar and balloon sounding data obtained from pre-Years Maritime Continent field campaign. Strong MJO activity took place in mid-December 2015 into January 2016. Radar observations revealed convergence convective cloud merger mesoscale systems eastward propagating westward moving...
Abstract A field observational campaign [i.e., the Mirai Indian Ocean cruise for Study of MJO-convection Onset (MISMO)] was conducted over central equatorial in October–December 2006. During MISMO, large-scale organized convection associated with a weak Madden–Julian oscillation (MJO) broke out, and some other notable variations were observed. Water vapor precipitation data show prominent 3–4-day-period cycle meridional wind υ variations. Filtered anomalies at midlevels reanalysis Japan...
Abstract The multiscale structure of a super cloud cluster (SCC) over the equatorial Indian Ocean, observed in November and December 2006, was investigated using data from satellite microwave sensors surface-based radars. smaller-scale this SCC marked by complicated relationship between rainfall systems upper-tropospheric shields, which moved eastward westward, respectively, with cycle 2–4 days. In analyses, attention given to slow eastward-propagating (5–11 m s−1) precipitating related...
[1] Equatorial westerly wind bursts (WWBs) and their relationship with El Nino–Southern Oscillation (ENSO) in the 18 climate models presented World Climate Research Programme's Coupled Model Intercomparison Project phase 3 (CMIP3) are examined. Some depict a realistic eastward shift of collective occurrences WWBs over Pacific as warm pool expands eastward. These that frequent western preceding Nino peak, known to trigger or enhance Nino, tend reproduce background states ENSO more accurately....
The high‐frequency time series data collected during 28th October to 21st November 2006 onboard R/V Mirai provided the first evidence of short‐term bio‐physical coupling in central equatorial Indian Ocean (EIO). predominant feature thermal structure was down‐sloping 28°C‐isotherm and up‐sloping 14°C‐isotherm indicating deepening surface‐layer shoaling lower‐thermocline respectively. Concomitant with surface‐layer, nitracline subsurface chlorophyll maximum (SCM) also deepened. From prominent...