著者

Joseph Q. Basconcillo Ger Anne W. Duran Aaron A. Francisco Rusy G. Abastillas Flaviana D. Hilario Edna L. Juanillo Ana Liza S. Solis Anthony Joseph R. Lucero Shalou-Lea A. Maratas

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.13, pp.114-119, 2017 (Released:2017-06-28)

参考文献数

21

被引用文献数

4 9

---

To overcome the limitation of low network density and sparse distribution of meteorological stations, spatial interpolation is being performed for estimating meteorological variables that are not geographically covered by existing observation network. While there are several readily available spatial interpolation techniques, it is still difficult to determine which one best estimates actual observation. Considering the stimulus for disaster risk reduction, hydrological, agricultural, and other applications of interpolated data, this study compared six interpolation techniques (Inverse Distance Weighted (IDW), Completely Regularized Spline (CRS), Tension Spline (TS), Ordinary Kriging (OK), Universal Kriging (UK), and ANUSPLIN) that have been recommended in tropical maritime region. Validation results comparing historical monthly and interpolated rainfall data from 1981-2010 in 65 stations in the Philippines show that OK has the best performance among the aforementioned techniques followed by ANUSPLIN and TS. Ultimately, this study is a contribution to the existing inadequate literatures that have documented and evaluated interpolation techniques that can be used in archipelagic regions with prominent climate variability.

著者

Masaki Katsumata Kyoko Taniguchi Tomoaki Nishizawa

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17, pp.c1-c4, 2021 (Released:2021-07-03)

参考文献数

1

著者

Ayako Seiki Yukari N. Takayabu Kunio Yoneyama Naoki Sato Masanori Yoshizaki

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.5, pp.93-96, 2009 (Released:2009-06-10)

参考文献数

26

被引用文献数

13 14

---

Oceanic responses to relatively strong Madden-Julian Oscillations (MJOs) and background winds controlled by El Niño-Southern Oscillation (ENSO) are examined. The MJO’s arrival excites dominant downwelling and upwelling Kelvin waves during El Niño developing (pre-El Niño: PEN) and other (non-PEN) phases, respectively. These opposite signals come from background wind directions under different ENSO phases and exert opposite impacts on SST. In addition, MJO convection itself develops accompanied by larger surface wind variations during PEN phases, which can be related to the interactive amplifications of synoptic- and planetary-scale disturbances when westerly wind bursts occur. Consequently, the strength of westerly forcing and its oceanic response during PEN phases are larger than that of the corresponding easterly forcing and its response during non-PEN phases. These results suggest that modulations of MJO amplitude and structure under the background westerly and easterly winds associated with ENSO phases exert opposite but asymmetric impacts on the ocean.

著者

Hiroaki Kawase Munehiko Yamaguchi Yukiko Imada Syugo Hayashi Akihiko Murata Tosiyuki Nakaegawa Takafumi Miyasaka Izuru Takayabu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.17A-002, (Released:2020-12-24)

被引用文献数

20

---

Impacts of historical warming on extremely heavy rainfall induced by Typhoon Hagibis (2019) are investigated using a storyline event attribution approach with the Japan Meteorological Agency Nonhydrostatic Model (JMA-NHM). Control experiments based on JMA mesoscale analysis data well reproduce the typhoon's track, intensity, and heavy precipitation. First, two non-warming experiments are conducted: One excludes both 40-year atmospheric and oceanic temperature trends from 1980 to 2019, and the other excludes the oceanic trend only. A comparison between control and non-warming experiments indicates that historical warming strengthens typhoons and increases the amount of total precipitation by 10.9% over central Japan. The difference between CTL and non-warming experiments without both atmospheric and oceanic temperature trends is larger than that without just the oceanic trend (7.3%). Additional sensitivity experiments without Japan's topography indicate that topography enhances not only total precipitation but also the changes in total precipitation due to historical warming. Through the storyline event attribution approach, it is concluded that historical warming intensifies strength of Typhoon Hagibis (2019) and enhances the extremely heavy precipitation induced by the typhoon.

著者

Ryuichi Kawamura Takuya Ogasawara

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.2, pp.37-40, 2006 (Released:2006-03-21)

参考文献数

14

被引用文献数

30 45

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The extratropical response to typhoon-related convective forcing over the western North Pacific in late summer is examined based on ECMWF global reanalysis (ERA-40) data during the 1958-2001 period. Typhoon activity is intimately associated with most of the major events in which an extratropical wavetrain structure prevails from the north of the Philippines through the central North Pacific. The vertical structure of the wavetrain pattern changes from baroclinic to a barotropic along the great circle. The analysis of the wave activity flux indicates that the extratropical wavetrain is stimulated by stationary Rossby waves. It was found that one or two typhoons, which are a synoptic-scale convective heat source over the western North Pacific, can induce the barotropic Rossby wavetrain and significantly influence the summer weather in the vicinity of Japan as remote forcing.

著者

Takuto Sato Hiroyuki Kusaka Hideitsu Hino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-018, (Released:2020-05-20)

被引用文献数

10

---

This study reveals the best combination of meteorological variables for the prediction of the number of emergency transport due to heat stroke over 64 years old in Tokyo metropolis based on a generalized linear model using 2008-2016 data. Temperature, relative humidity, wind speed, and solar radiation were used as candidates of the explanatory variables. The variable selection with Akaike's information criterion (AIC) showed that all the four meteorological elements were selected for the prediction model. Additional analysis showed that the combination of daily mean temperature, maximum relative humidity, maximum wind speed, and total solar radiation as explanatory variables gives the best prediction, with approximately 19% less error than the conventional single-variable model which only uses the daily mean temperature. Finally, we quantitatively estimated the relative contribution of each variable to the prediction of the daily number of heat stroke patients using standardized partial regression coefficients. The result reveals that temperature is the largest contributor. Solar radiation is second, with approximately 20% of the temperature effect. Relative humidity and wind speed make relatively small contributions, each contributing approximately 10% and 9% of the temperature, respectively. This result provides helpful information to propose more sophisticated thermal indices to predict heat stroke risk.

著者

Masaki Katsumata Kyoko Taniguchi Tomoaki Nishizawa

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.16A-002, (Released:2020-05-19)

被引用文献数

2

---

A shipboard lidar system was examined the capability to retrieve detailed variation of the water vapor mixing ratio in and above the marine atmospheric boundary layer (MABL). The water vapor mixing ratio is retrieved from the ratio of Raman lidar signals by water vapor and by nitrogen, with the help of radiosonde data beside. Data obtained during two special observations, Pre-YMC and YMC-Sumatra, off the west coast of Sumatra island were examined. The mixing ratio was retrieved in the nighttime over 1 km height with the resolution of 10-minutes in temporal and 120-meters in vertical. The root mean square difference from the radiosonde data is about or less than 1 g/kg in MABL. A case study demonstrates that the retrieved spatiotemporal variation of water vapor mixing ratio captures meso-scale drying and moistening in detail. The capabilities of the retrieved data were well demonstrated, while number of improvements are expected in future work.

著者

Satoru Yokoi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.16A-001, (Released:2020-05-15)

被引用文献数

4

---

Given vigorous mean diurnal variation (MDV) of cumulus convection and surface wind over coastal waters of Indonesian Maritime Continent, surface sensible and latent heat fluxes (SHF and LHF) are expected to also exhibit significant MDV. However, it is difficult to grasp characteristics of MDV of these fluxes due to lack of surface observation data. Recently, two intensive observation campaigns were conducted off the west coast of Sumatra Island in boreal winter, which offer us a unique opportunity to examine the characteristics of convection and the fluxes. This study analyzes these observations to reveal that the MDV of both SHF and LHF has considerable amplitude compared with the average. The MDV of SHF is primarily caused by that in surface air temperature, which is due to the MDV of the convection. As for LHF, the MDV is primarily caused by that of surface wind speed, in which both the MDV of convection and sea/land breezes play roles. Furthermore, there are qualitative differences in the MDV of the fluxes between the two campaign periods, which can be explained from the viewpoint of differences in phase and intensity of MDV of convection and the sea/land breezes.

著者

Noriko N. Ishizaki Motoki Nishimori Toshichika Iizumi Hideo Shiogama Naota Hanasaki Takahashi Kiyoshi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-014, (Released:2020-04-01)

被引用文献数

24

---

Bias corrected climate scenarios over Japan were developed using two distinct methods, namely, the cumulative distribution function-based downscaling method (CDFDM) and Gaussian-type Scaling approach (GSA). We compared spatial distribution, monthly variation, and future trends. The seasonal distribution of bias-corrected data using CDFDM closely followed the original general circulation model (GCM) outputs. GSA overestimated the amount of precipitation by 12-18% in every season because of an unsuitable assumption on the probability distribution. We also examined the contributions of each source of the uncertainty in daily temperature and precipitation indices. For daily temperature indices, GCM selection was the main source of uncertainty in the near future (2026-2050), while different Representative Concentration Pathways (RCPs) resulted in large variability at the end of the 21st century (2076-2100). We found large uncertainty using the bias-correction (BC) methods for daily precipitation indices even in the near future. Our results indicated that BC methods are an important source of uncertainty in climate risk assessments, especially for sectors where precipitation plays a dominant role. An appropriate choice of BC, or use of different BC methods, is encouraged for local mitigation and adaptation planning in addition to the use of different GCMs and RCPs.

著者

Ayataka Ebita Shinya Kobayashi Yukinari Ota Masami Moriya Ryoji Kumabe Kazutoshi Onogi Yayoi Harada Soichiro Yasui Kengo Miyaoka Kiyotoshi Takahashi Hirotaka Kamahori Chiaki Kobayashi Hirokazu Endo Motomu Soma Yoshinori Oikawa Takahisa Ishimizu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.7, pp.149-152, 2011 (Released:2011-10-06)

参考文献数

24

被引用文献数

289 412

---

The Japan Meteorological Agency (JMA) started the second Japanese global atmospheric reanalysis project named the Japanese 55-year Reanalysis (JRA-55). It covers 55 years, extending back to 1958, when the global radiosonde observing system was established. Many of the deficiencies found in the first Japanese reanalysis, the Japanese 25-year Reanalysis (JRA-25), have been improved. It aims at providing a comprehensive atmospheric dataset that is suitable for studies of climate change or multi-decadal variability, by producing a more time-consistent dataset for a longer period than JRA-25.Production of JRA-55 started in 2010, and computations for more than 16 years have been completed as of August 2011. The entire JRA-55 production will be completed in early 2013 and thereafter JRA-55 will be continued as a new JCDAS on real time basis. This paper is a brief report to introduce the JRA-55 reanalysis project. The data assimilation and prediction (DA) system used in JRA-55 is introduced and compared to that used in JRA-25. Early results of JRA-55 are presented and discussed, showing general improvements.

著者

Yuhei Takaya

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.15A-010, (Released:2019-07-08)

被引用文献数

15

---

The western North Pacific (WNP) exhibited markedly enhanced tropical cyclone (TC, typhoon) activity during the boreal summer (June–August) of 2018; 18 named typhoons were generated and 13 of these approached near Japan, causing serious damage and disruption in the country. During the summer of 2018, warm sea surface temperature persisted over the tropical Northeastern Pacific, which are typical oceanic conditions of a positive phase of the Pacific meridional mode (PMM), while no El Niño condition was observed. The Japan Meteorological Agency seasonal forecast system successfully predicted the enhanced TC activity in the WNP as well as associated seasonal characteristics such as a deep monsoon trough and active convection. Results of sensitivity experiments clearly indicate that the positive phase of the PMM played a major role in establishing the active TC conditions in the WNP during the summer of 2018 and reveal predictable seasonal processes of TC activity (genesis and tracks) during the summer of 2018, when there was no El Niño.

著者

Yasumitsu Maejima Keita Iga Hiroshi Niino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.2, pp.80-83, 2006 (Released:2006-06-29)

参考文献数

10

被引用文献数

2

---

Upper-tropospheric vortices having a horizontal wavelength of 300-400 km were observed on water vapor images of the Japanese geostationary satellite (MTSAT-1). Grid point values predicted by the Regional Spectral Model of the Japan Meteorological Agency show that the vortices were located along a zonal belt with strong cyclonic shear and horizontal convergence. A quasi-geostrophic linear stability analysis of the basic flow having horizontal and vertical shear shows that the fastest growing mode has a horizontal wavelength, a phase speed and a growth rate that reasonably agree with those of the satellite observation. The amplitude of the fastest growing mode is confined to a region having a meridional width of 2 degrees and a vertical depth of 2 km. An energy budget analysis shows that barotropic instability is the dominant generation mechanism for the growing mode.

著者

Akifumi Nishi Hiroyuki Kusaka Lidia Lazarova Vitanova Yuma Imai

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2019-024, (Released:2019-05-27)

被引用文献数

5

---

We quantitatively evaluated the contributions of foehn winds and the urban heat island (UHI) effect to an extreme high-temperature nocturnal event at Niigata city on 23-24 August 2018. During this event, southeasterly winds blew continually across the Niigata Plain and temperatures on the plain were higher than those in the windward region of the mountain range. Back-trajectory analysis and numerical simulations with and without topography showed that the southeasterly winds were foehn winds that caused precipitation and latent heating on the windward slope of the mountain range. The foehn winds and UHI contributed about 2.8°C and 1.9°C, respectively, to the extreme high-temperature of 31.0°C at 2100 JST in Niigata city. The combined impact of the foehn winds and the UHI at Niigata was about 4.0°C during the night. The contribution of the foehn winds was greater at around midnight, whereas that of the UHI was greater during the early night.

著者

Takumi Matsunobu Mio Matsueda

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.15A-004, (Released:2019-05-24)

被引用文献数

8

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Extremely heavy rainfall events occurred over western Japan in early July 2018. This study assesses the predictability of these events for the period 5th–7th July using three operational medium-range ensemble forecasts available from the European Centre for Medium-range Weather Forecasts (ECMWF), the Japan Meteorological Agency (JMA), and the National Centers for Environmental Prediction (NCEP), and ensemble simulations conducted with an ECMWF model and NCEP operational ensemble initial conditions. All three operational ensembles predicted extreme rainfall on 5th–6th July at lead times of ≤ 6 days, indicating the high predictability of this event. However, the extreme rainfall event of 6th–7th July was less predictable. The NCEP forecasts, initialised on 30th June, performed better at predicting this event than the other operational forecasts. The JMA forecasts initialised on 1st July showed improved predictability; however, the ECMWF forecasts initialised after 30th June showed only gradual improvements as the initialisation time progressed. The ensemble simulations revealed that the lower predictability of the rainfall in the ECMWF forecasts on 6th–7th July can be attributed to the model rather than to the initial conditions. Accurate prediction of the North Pacific Subtropical High is a prerequisite for accurate prediction of such extreme rainfall events.

著者

Kenji Suzuki Rimpei Kamamoto Katsuhiro Nakagawa Michinobu Nonaka Taro Shinoda Tadayasu Ohigashi Yukiya Minami Mamoru Kubo Yuki Kaneko

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2019-018, (Released:2019-04-10)

被引用文献数

5

---

A field observation was carried out along the coast of the Japan Sea in the 2016-2017 and 2017-2018 winter seasons, using the Ground-based Precipitation particle Image and Mass Measurement System (G-PIMMS) to evaluate the Global Precipitation Measurement Mission (GPM) dual-frequency precipitation radar (DPR) precipitation type classification algorithm. The G-PIMMS was installed at Kanazawa University and Ishikawa Prefectural University, which are around 10 km apart from each other. The G-PIMMS observations showed that the major precipitation particle type (graupel or snowflake) was different in the precipitation types classified by the GPM DPR algorithm.

著者

Shunji Kotsuki Koji Terasaki Kaya Kanemaru Masaki Satoh Takuji Kubota Takemasa Miyoshi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15A, pp.1-7, 2019 (Released:2019-01-26)

参考文献数

25

被引用文献数

26

---

This paper is the first publication presenting the predictability of the record-breaking rainfall in Japan in July 2018 (RJJ18), the severest flood-related disaster since 1982. Of the three successive precipitation stages in RJJ18, this study investigates synoptic-scale predictability of the third-stage precipitation using the near-real-time global atmospheric data assimilation system named NEXRA. With NEXRA, intense precipitation in western Japan on July 6 was well predicted 3 days in advance. Comparing forecasts at different initial times revealed that the predictability of the intense rains was tied to the generation of a low-pressure system in the middle of the frontal system over the Sea of Japan. Observation impact estimates showed that radiosondes in Kyusyu and off the east coast of China significantly reduced the forecast errors. Since the forecast errors grew more rapidly during RJJ18, data assimilation played a crucial role in improving the predictability.

著者

Tetsuya Takemi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2018-027, (Released:2018-10-12)

被引用文献数

35

---

An extreme, damaging rainfall occurred in northern Kyushu in July 2017. Whether such an extreme rainfall is quantitatively captured by numerical models is a challenging issue. We investigate the influences of terrain representation in simulating a stationary convective system and the resulting heavy rainfall for this case by conducting a series of 167-m-resolution numerical experiments. By employing a high-resolution elevation dataset as well as a double-moment cloud microphysics scheme, the control experiment successfully reproduced the stationary, linear-shaped convective system and the associated heavy rainfall. When the model terrain was created by a coarser-resolution elevation dataset, the 167-m-resolution experiment underestimated the accumulated rainfall, because of discretely developing convection and weaker intensities of the rainfall.These impacts of the terrain representation were confirmed to be robust through conducting another experiments with a different microphysics scheme. The representation of model terrains is critically important in simulating stationary convective systems and quantitatively the resulting heavy rainfall.

著者

Wataru Mashiko Hiroshi Niino

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.13, pp.135-139, 2017 (Released:2017-07-31)

参考文献数

26

被引用文献数

6

---

A super high-resolution simulation of the 6 May 2012 Tsukuba supercell tornado with a horizontal grid spacing of 10 m is conducted to investigate its fine-scale structure under realistic environmental conditions including surface friction. The simulated tornado repeatedly exhibits evolutions from one-cell to two-cell vortex, and subsequently to a multiple-vortex structure, where the vortex structure is sensitive to a swirl ratio. Subvortices in the multiple-vortex structure are located on the immediate inside of the radius of the maximum tangential wind speed, and cyclonically rotate around the tornado center with a slower speed less than half of the maximum tangential wind speed. The subvortices have a feature of a suction vortex accompanied by strong horizontal convergence and strong updraft near the surface. Although a superposition of the swirling winds associated with the subvortices and the parent tornado vortex causes locally intensified winds, the maximum horizontal and upward winds over the tornado's lifetime occur at the stage of shrinking of the vortex radius right before a transition to a multiple-vortex structure.

著者

Hiroaki Miura

出版者

(公社)日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.13, pp.69-73, 2017 (Released:2017-04-25)

参考文献数

18

被引用文献数

3

---

A shallow water model is developed on the regular hexagonal mesh by combining the hexagonal B1-grid and B2-grid schemes. The new scheme called as the hexagonal synchronized B-grid (SB-grid) scheme in this work allows avoiding a computational mode problem of the ZM-grid scheme. It is known that the problem is caused by the mismatch of degrees of freedoms of the prognostic variables. The SB-grid uses the same variable arrangement as the ZM-grid, placing fluid depths and fluid velocities at the centers and corners of hexagonal cells, respectively, but the nonlinear terms of the momentum equation are discretized using wider spatial stencils than those of the ZM-grid. This change results in the inhibition of extra interactions in the velocity fields that enhances a computational mode in the ZM-grid. Geostrophic adjustment tests on a regular hexagonal mesh confirm that the SB-grid shallow water model behaves almost equivalently to the Z-grid model, and the computational mode problem is certainly settled down.

著者

Yasumitsu Maejima Masaru Kunii Takemasa Miyoshi

出版者

(公社)日本気象学会

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.13, pp.174-180, 2017 (Released:2017-09-27)

参考文献数

37

被引用文献数

14

---

This study aims to investigate the impacts of 30-second-update and 100-m-resolution data assimilation (DA) on a prediction of sudden local torrential rains caused by an isolated convective system in Kobe city on 11 September 2014. We perform a Local Ensemble Transform Kalman filter (LETKF) experiment with the Japan Meteorological Agency non-hydrostatic model (JMA-NHM) at 1-km and 100-m resolution using every-30-second radar reflectivity observed by the phased array weather radar (PAWR) at Osaka University. The 1-km-mesh experiment shows that 30-second-update PAWR DA has positive impacts on the analyses and forecasts. Moreover, the 100-m-mesh experiment shows significant advantages in representing the rainfall intensity and fine structure of the convective system. The promising results suggest that 30-second-update, 100-m-mesh DA have a great potential for predicting sudden local rain events.