Mikiko Fujita

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Verified

Mikiko verified their affiliation via an institutional email.

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• PhD
• Senior Researcher at Japan Agency for Marine-Earth Science and Technology

Precipitable water vapor (PWV) was measured using a shipborne Global Positioning System (GPS) during a two month cruise in the equatorial Indian Ocean. More than 300 profiles were also observed by radiosondes released from the ship during the experiment. GPS atmospheric delay and PWV was estimated and compared to the radiosonde observations. The GP...

The authors investigated diurnal convection peak characteristics over the eastern Indian Ocean off the island of Sumatra during different phases of the Madden-Julian oscillation (MJO). During MJO phases 2 to 3 (P2 and P3) defined by Wheeler and Hendon (2004), prominent diurnal variation in convection was observed by satellites when moderate low-lev...

Extremely heavy precipitation affects human society and the natural environment, and its behaviour under a warming climate needs to be elucidated. Recent studies have demonstrated that observed extreme precipitation increases with surface air temperature (SAT) at approximately the Clausius–Clapeyron (CC) rate, suggesting that atmospheric water vapo...

We report experimental observations of precipitable water vapor (PWV) derived using Global Positioning System/Global Navigation Satellite System (GPS/GNSS) receivers mounted on autonomous surface vehicles (ASVs), which were deployed in the tropical Pacific Ocean from July to September 2018. The GPS atmospheric delay was estimated by precise point p...

An array of atmospheric profile observations consists of three‐dimensional vectors representing pressure, temperature, and humidity, with each profile forming a continuous curve in this three‐dimensional space. In this paper, the Signature method, which can quantify a profile's curve, was adopted for the atmospheric profiles, and the accuracy of pr...

Tornadoes are responsible for several high-impact weather disasters in Japan. However, little is known about how these events have changed over the last several decades or how they may change in future climates. This study examines environmental conditions associated with tornados in Japan using pseudo-soundings from the high-resolution fifth-gener...

Under the international field program Years of the Maritime Continent (YMC), we conducted a field campaign YMC-Boreal Summer Monsoon study in 2020 (YMC-BSM 2020) in the tropical western Pacific in August-September 2020. While this campaign was aimed to capture and understand the behavior of northward propagating boreal summer intraseasonal oscillat...

Tornadoes are responsible for several high impact weather related disasters in Japan. However, little is known about how these events have changed over the last several decades or how they may change in future climates. This study examines environmental conditions associated with tornados in Japan using pseudo-soundings from the high-resolution fif...

This short article describes humidity data correction based on intercomparison between the two manufacturers' radiosondes with the assessment using precipitable water vapor (PWV) derived from Global Navigation Satellite System (GNSS) signals. In addition, we propose a method to determine whether the same correction procedure can be applied for the...

To investigate future changes in snow cover and snowfall over mountainous areas in central Japan, we conducted regional climate projections using a high-resolution non-hydrostatic regional climate model (NHRCM) with 5 km and 1 km grid spacings. Boundary conditions are derived from the database for Policy Decision making for Future climate change (d...

This study investigates future changes to extremely cool days (ECDs) during the summer (June-August) season in northeastern Japan by applying self-organizing map (SOM) technique to large ensemble simulations from the “database for Policy Decision making for Future climate change” (d4PDF). Two separate SOMs, one trained on mean sea level pressure us...

Analyses of large ensemble data on future climate are significantly useful for the probabilistic future projection of climate change in various interdisciplinary fields. However, the data volume of the Database for Policy Decision making for Future climate change or d4PDF, which is a mega-ensemble dataset, exceeds ∼ 3 PB, which is too large to down...

We have recently experienced several heavy snowfall events, but still do not sufficiently understand how global warming will impact changes in local extreme snowfall events. The analysis relevant to the extreme events requires ensemble experiments with high‐resolution regional climate modeling. In this study, we use a large number of ensemble warmi...

Analyses of large ensemble data of future climate are quite useful in order to provide probabilistic future projection of climate change in various interdisciplinary fields related to, e.g., hydrology, civil engineering and adaptation planning in response to global warming. Ensemble data of "+2K near-future climate simulations" are currently genera...

Analyses of large ensemble data of future climate are quite useful in order to produce proba-bilistic future projection of climate change in various interdisciplinary fields. However, the data volume of the d4PDF exceeds ∼3 PB which is to large to download to local computers of users. In order to provide functions to retrieve and download necessary...

We investigated extremely heavy precipitation that occurred around the Kinugawa River, Japan, in September 2015, and the probability of extreme precipitation occurrence, using data from a large ensemble forecast more than 1,000 members that were dynamically downscaled to 1.6 km horizontal grid spacing. The observed event was statistically rare amon...

Future changes in the climatological distribution of clear air turbulence (CAT) and its seasonality over the North Pacific are estimated based on an ensemble of climate projections under warming for the globally averaged surface air temperature of 2 K relative to pre-industrial levels, which includes over 3000 years of ensembles using a 60-km atmos...

This study examines long-term ensemble projections for historical and future climate conditions over 5,000 years using an atmospheric global circulation model. The future climate condition is assumed as a constant +4°C in the global mean temperature from before the Industrial Revolution (c.a. 1850), and the historical climate condition is perturbed...

Plain Language Summary Our study shows the precipitation changes in the near‐future around the 2040s, +2‐K climate. Even in the +2‐K climate, both extreme precipitation and dryness in the extratropics increase significantly. These results urge to plan for adaptation to extreme weather in the near future. The 2‐K warming climate simulation was perfo...

The incremental dynamical downscaling and analysis system (InDDAS) which has been developed from the pseudo-global-warming method by appending partial functions was applied for a probabilistic regional scale climate change projection with the target regions of Kanto and Japan Alps. In InDDAS, the most reliable future state was projected by a region...

We investigated climate change in the annual snow cover period in mountainous areas of central Japan by downscaling simulations of four climate change projections based on a Coupled Model Intercomparison Project phase 3 (CMIP3) Special Report on Emission Scenarios (SRES) A1B emission scenario using a regional climate model. Our numerical simulation...

Dynamical downscaling is a promising tool to assess the future fate of water in a catchment. To overcome strong biases in Coupled Ocean-Atmosphere General Circulation Models (CGCMs), the Pseudo Global Warming Downscaling (PGW-DS), which combines climatology differences (future-past) of CGCM ensembles and Reanalysis Dataset (RD) was proposed as a re...

An experimental cruise was conducted around the west side of the North Pacific Ocean with a global navigation satellite system (GNSS) antenna, which was installed facing the zenith on the deck of the 3,991-ton research vessel "Hakuho Maru" to investigate the benefits of multi-GNSS processing. More than 100 profiles were also observed by radiosondes...

Snowfall amounts have fallen sharply along the eastern coast of the Sea of Japan since the mid-1980s. Toyama Prefecture, located approximately in the center of the Japan Sea region, includes high mountains of the northern Japanese Alps on three of its sides. The scarcity of meteorological observation points in mountainous areas limits the accuracy...

Difference of diurnal cycle of precipitation over the eastern Indian Ocean off Sumatra Island between positive and negative Indian Ocean Dipole (IOD) phases was investigated by using regional numerical model. During negative IOD phase, which are defined by the Dipole Mode Index of Saji et al., prominent precipitation peak was simulated over the lan...

Regional scale climate change projections play an important role in assessments of influences of global warming and include statistical (SD) and dynamical downscaling (DD) approaches. One of DD methods is developed basing on the pseudo-global-warming (PGW) method developed by Kimura and Kitoh (2007) in this study. In general, DD uses regional clima...

Seven major reanalyses of precipitable water (PW) are compared in this paper. In addition, using a regional climate model, we also investigated the impact of the boundary conditions on downscaling simulations in the tropics with a particular focus on the differences in the absolute value of PW among reanalyses. Results showed that the absolute am...

We focus on the dramatic decrease in the snow cover on the Japan Sea side of Central Japan in the late 20th century. Using a regional climate model, a control experiment (CTL) was conducted, and it accurately simulated the dramatic decrease in maximum snow depth (SNDmax) between the 1980s and the 1990s. We then conducted a pseudo climate simulation...

A novel project (GPS pRecipitable wAter reSearch Project) GRASP has been launched to investigate variations of precipitable water vapor caused by the climate change. The water vapor is one of the greenhouse gases, which is more effective than CO2, so it is important to observe water vapor change for a long period. More than 1,000 points stationary...

A field observational campaign [i.e., the Mirai Indian Ocean cruise for the Study of the MJO-convection Onset (MISMO)] was conducted over the central equatorial Indian Ocean 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 wer...

This paper describes the formation mechanism of morning maximum in the diurnal cycle of precipitation, at the Strait of Malacca under a calm condition, with a nonhydrostatic mesoscale numerical model and ship-based observational data. The morning precipitation peak at the strait is induced by the convergence of two cold outflows that have been prod...

The present paper investigates the relationship between the skin sea surface temperature (SSTskin) and the precipitable water (PW) observed over the tropical Indian Ocean. PW is derived from a shipborne Global Positioning System (GPS). Composite diurnal variations indicate that the increase of PW and radar echo coverage (rainfall) in the daytime co...

1] This paper describes the structure and evolution of northward propagating mesoscale convective systems (MCSs) observed over the tropical western Pacific on 15 June 2005. A wedge-shaped convective cloud area, consisting of three groups of MCSs, was generated near the equator to the north of New Guinea at around 0000 LST on 15 June, and one of the...

The Mirai Indian Ocean cruise for the Study of the Madden–Julian oscillation (MJO)-convection Onset (MISMO) was a field experiment that took place in the central equatorial Indian Ocean during October–December 2006, using the research vessel Mirai, a moored buoy array, and land-based sites at the Maldive Islands. The aim of MISMO was to capture atm...

Atmospheric soundings using the Vaisala RS92 radiosonde were intensively conducted during the field experiment MISMO (Mirai Indian Ocean cruise for the Study of the MJO-convection Onset) in the central and eastern equatorial Indian Ocean from October to December 2006. By comparing the RS92 relative humidity data with that from the Meteolabor Snow W...

The effect of the assimilation of dropsonde data over the tropical western Pacific was investigated in an objective analysis. In June 2005, 30 dropsondes were released on four separate flight days. The data impact was assessed using the objective analysis dataset of “ALERA.” The analysis of the zonal wind field over the tropical western Pacific in...

A remarkable decrease in water vapor was observed during daytime on calm days over coastal Thailand. Precipitable water vapor (PWV) and surface specific humidity (SSH) decreased by about 5 mm and 3 g kg ⁻¹, respectively, in Bangkok from the late morning to the late afternoon on sunny days with weak low-level winds between March 1998 and December 19...

Diurnal variation of precipitation was investigated over Palau in the tropical western Pacific. Compared to other larger islands, heating effect of the island is assumed to be small in Peleliu Island. Peleliu Island was chosen for the representative of oceanic feature. Over Palau region, the season can be divided into westerly and easterly wind reg...