著者

Yuta Katsuyama Masaru Inatsu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17, pp.35-40, 2021 (Released:2021-02-25)

参考文献数

24

被引用文献数

2

---

This study developed a volume scan-type disdrometer and investigated the size distribution of solid-precipitation particles observed by flux- and volume-scan type disdrometers, installed in 2016-2017 winter in Sapporo, Japan. The former disdrometer detected particles, by line sensors, of which frequency is proportional to the particle number per area. On the other hand, the latter directly observed the particle number per volume using an image sensor. The flux-scan data are known to have the bias of more frequency in higher-speed (or larger-size) particles, but this bias was hardly corrected due to the error of estimated particles' velocity. It was first validated that the volume scan-type disdrometer could observe particle size between 0.5 mm and 13 mm, consistently with the flux scan-type one. Then, we examined how many events showed the difference of the size distribution between the two disdrometers with the Kolmogorov-Smirnov test. The result showed that 84% of the total events examined fell into the class where they were significantly different, partially due to fast-falling graupels.

著者

Satoshi Iizuka Ryuichi Kawamura Hisashi Nakamura Toru Miyama

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17A, no.Special_Edition, pp.21-28, 2021 (Released:2021-02-23)

参考文献数

19

被引用文献数

11

---

Typhoon Hagibis (2019) caused widespread flooding and damage over eastern Japan. The associated rainfall maxima were primarily observed on the windward mountain slopes along with the west of the leading edge of a low-level front. Concomitantly, a significant positive value in sea surface temperature anomalies (SSTAs) was observed in association with an ocean eddy over the Oyashio region, together with anomalous warmth over the entire western North Pacific. The present study examines the role of the SSTAs in the rainfall distribution associated with Hagibis, to deepen our understanding of the influence of the midlatitude ocean on tropical cyclones and associated rainfall. Our sensitivity experiments demonstrate that the observed warm SSTAs had the potential to displace the rainfall caused by Hagibis inland and thereby acted to increase precipitation along the Pacific coast of northeastern Japan. Our results suggest that midlatitude SSTAs on ocean-eddy scales can also influence the synoptic-scale atmospheric front and associated heavy rainfall.

著者

Koichi Shiraishi Takashi Shibata

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2021-005, (Released:2021-01-25)

被引用文献数

2

---

Stratospheric aerosols over the high Arctic at Ny Ålesund, Svalbard (79°N, 12°E) were observed continuously for four years from March 2014 by a lidar system using the second harmonic wavelength (532 nm) of the Nd:YAG laser. Our observations reveal the seasonal features of stratospheric aerosols and the arrival of the smoke at the high Arctic from Canadian forest-fire in August 2017. We estimated the seasonal variation for three years before the Canadian forest-fire when there was no apparent volcanic effect. In the estimation, we removed polar stratospheric clouds by the threshold temperature of their formation. The seasonal variation for the three years is that the vertical profiles of the backscattering ratio take a maximum value of about 1.05-1.06 at altitudes between 13 and 16 km from December to March, and about 1.02-1.04 at altitudes between 17 and 20 km from April to November. These results are compared with the results observed at the low Arctic, northern Norway. We also present the increases in the backscattering ratio and the volume depolarization ratio from September to December 2017 caused by the smoke from the Canadian forest-fire.

著者

Akiyoshi Wada Johnny C. L. Chan

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.17A-005, (Released:2021-01-11)

被引用文献数

9

---

In the 2019 tropical cyclone season in the western North Pacific, Typhoons FAXAI and HAGIBIS made landfall in Japan while keeping the intensity, resulting in serious disasters. This study addresses the influences of an increasing trend and variations in the upper ocean heat content above 26°C (tropical cyclone heat potential: TCHP) from January 1982 to June 2020 on FAXAI and HAGIBIS. TCHP underneath FAXAI and HAGIBIS in 2019 was higher than the climatological mean except for a part of mature phase of HAGIBIS due to HAGIBIS-induced sea surface cooling. TCHP significantly increased with the interannual oceanic variations (IOVs) in the subtropical (15-20°N, 140-150°E) and midlatitude (30-35°N, 130-140°E) areas where FAXAI and HAGIBIS intensified or kept the intensity. From an empirical orthogonal function (EOF) analysis of TCHP, we demonstrate that the leading three EOF modes of TCHP explains approximately 76.8% of total variance, but the increase in TCHP along the tracks of FAXAI and HAGIBIS particularly in the early intensification of HAGIBIS cannot be explained only by the IOVs included in the leading three EOF modes but rather by the warming trend irrespective of the IOVs.

著者

Kosuke Ito Hana Ichikawa

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17A, no.Special_Edition, pp.1-6, 2021 (Released:2021-01-01)

参考文献数

18

被引用文献数

7

---

One of the remarkable environmental characteristics of tropical cyclone (TC) Hagibis (2019) was the positive sea surface temperature (SST) anomaly observed in the western North Pacific Ocean. In this study, an ensemble-based sensitivity experiment was conducted with a nonhydrostatic model, focusing on the impact of SST on TC motion. The TC with the analyzed SST (warm run) moved faster near mainland Japan than with the lowered SST (cold run), as the TC in the warm run was embedded earlier in the mid-latitude westerly jet located to the north than that in the cold run. The TC displacement was consistent with the large decrease of geopotential height at 500-hPa (Z500) in the north of TC Hagibis during the warm run. Further investigation showed that the approach to the westerly jet presumably induced the low local inertial stability as well as the southwesterly vertical wind shear enhancing the upward mass flux in the north of the TC. They led the enhanced upper-tropospheric northward outflow from the TC energized by the warm SST, and it resulted in the decrease of the Z500 in the north. This study suggests that warm SST can affect TC tracks through interaction with mid-latitude westerly jets.

著者

Lusha Wang Ayumi Kotani Takafumi Tanaka Takeshi Ohta

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.259-264, 2020 (Released:2020-12-24)

参考文献数

20

被引用文献数

1

---

Based on the drought severity index (DSI), which is derived from the ratio of evapotranspiration (ET) to potential evapotranspiration (PET) and normalized difference vegetation index (NDVI), as measured by remote sensing, we replaced the ET/PET ratio with soil moisture (0-10 cm) to establish an improved index (IDSI) and evaluated the drought situation in Inner Mongolia. The two components in IDSI are independently derived; however, the effects of evapotranspiration are contained in the soil moisture, and even precipitation changes could be reflected. We used monthly IDSI data for Inner Mongolia to evaluate drought throughout the growing season (May–September) during 2001-2010. The IDSI showed that 2001, 2007, and 2009 were years with significant drought. Areas that experienced extreme drought were less extensive than those found by the DSI because we removed the ET/PET component, which already contains the effects of the NDVI. IDSI results not only contained the degree of precipitation change for a given month through soil moisture, but also reflected the influence of water and heat in the previous month through the NDVI. Moreover, IDSI results were generally consistent with agricultural drought disaster records.

著者

Yu Li Shuqing Ma Ling Yang Xiaoqiong Zhen Dan Qiao

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.252-258, 2020 (Released:2020-12-23)

参考文献数

28

---

Array weather radar (AWR), a kind of distributed phased array radar, includes at least three Phased Array Front Ends (PAFE). Every three PAFEs are grouped for synchronous scanning to ensure that the Data Time Difference (DTD) at the same point in the fine detection area is less than 2 s. This paper adopts the multiple-Doppler wind synthesis method to synthesize the wind field of the small-DTD AWR data and discusses the sensitivity analysis on the wind fields under the different DTDs. The analysis experiment includes the wind fields under two types of precipitation systems. One is a convective precipitation system with unstable airflow, and the other is a non-convective precipitation system with stable airflow. The statistical analysis showed that, due to the advection effect and intrinsic evolution of the precipitation systems, the bigger the DTD is, the bigger the wind field error is. When the DTD is greater than 24 s, the wind field obtained by the convective precipitation system has more errors. When the DTD is greater than 84 s, the wind field obtained by the non-convective precipitation system has more errors.

著者

Tomoe Nasuno

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2021-003, (Released:2020-12-23)

被引用文献数

1

---

Relationship between diurnal convection and the intraseasonal oscillation (ISO) over the western Maritime Continent (MC) was investigated by a case study of an ISO event that occurred during the Years of the Maritime Continent (YMC)-Sumatra 2017 campaign. Two sets of global cloud-permitting simulations using cloud microphysics settings for ISO prediction (CTL) and for climate simulation (MOD) were performed to clarify their impacts. CTL had biases of weaker diurnal variation and smaller precipitation amounts over land than in observations; these were reduced in MOD by higher probabilities of local intense convection in the middle troposphere and higher precipitation efficiency. The enhanced convection over land coincided with suppressed convection over the surrounding ocean, especially at the diurnal peak time of land convection. Exception is the onset period of the ISO convection, when upward moisture advection and precipitation increased also over ocean in MOD than in CTL at the diurnal peak time of oceanic convection. These results suggest that the enhancement of local convection over the MC by the cloud microphysical processes basically hinder the ISO convection by the activation of land convection, but it also favors the ISO convection development over ocean during the onset period.

著者

Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki Izuru Takayabu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.17A-003, (Released:2020-12-16)

被引用文献数

8

---

Numerical experiments on Typhoon Trami (2018) using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model in current and pseudo-global warming (PGW) climates were conducted to investigate future changes of a slow-moving intense typhoon under the warming climate. Over the warmer sea in the PGW climate, the maximum near-surface wind speed rapidly increased around the large eye of the simulated Trami. The stronger winds in the PGW simulation versus the current simulation caused a 1.5-fold larger decrease of sea surface temperature (SST) in the storm core-region. In the PGW climate, near-surface air temperature increased by 3.1°C. A large SST decrease due to ocean upwelling caused downward heat fluxes from the atmosphere to the ocean. The magnitude of the SST decrease depended strongly on initial ocean conditions. Consideration of the SST decrease induced by an intense typhoon, and a slow-moving storm in particular, indicated that such a typhoon would not always become more intense under the warmer climate conditions. An atmosphere–ocean coupled model should facilitate making more reliable projections of typhoon intensities in a warming climate.

著者

Lusha Wang Ayumi Kotani Takafumi Tanaka Takeshi Ohta

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-043, (Released:2020-11-23)

被引用文献数

1

---

Based on the drought severity index (DSI), which is derived from the ratio of evapotranspiration (ET) to potential evapotranspiration (PET) and normalized difference vegetation index (NDVI), as measured by remote sensing, we replaced the ET/PET ratio with soil moisture (0-10 cm) to establish an improved index (IDSI) and evaluated the drought situation in Inner Mongolia. The two components in IDSI are independently derived; however, the effects of evapotranspiration are contained in the soil moisture, and even precipitation changes could be reflected. We used monthly IDSI data for Inner Mongolia to evaluate drought throughout the growing season (May–September) during 2001-2010. The IDSI showed that 2001, 2007, and 2009 were years with significant drought. Areas that experienced extreme drought were less extensive than those found by the DSI because we removed the ET/PET component, which already contains the effects of the NDVI. IDSI results not only contained the degree of precipitation change for a given month through soil moisture, but also reflected the influence of water and heat in the previous month through the NDVI. Moreover, IDSI results were generally consistent with agricultural drought disaster records.

著者

Kazuo Saito Takumi Matsunobu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.198-205, 2020 (Released:2020-11-04)

参考文献数

25

被引用文献数

5

---

Heavy rainfalls often occur when a tropical cyclone (TC) exists on the sea off the south coast. These pre-typhoon rainfalls (PRE) is associated with the northward moisture transport ahead of the TC. In this paper, we examine the northward moisture transport by the ageostrophic winds associated with typhoon T0918 (Melor) and its impact on PRE. According to a numerical simulation conducted in the previous study (Saito 2019), we analyzed the northward moisture fluxes by reproduced geostrophic and ageostrophic winds. Although the southerly ageostrophic winds are dominant mainly in the upper levels, the ageostrophic winds contribute to enhance the poleward water vapor transport for the upper and middle levels above 3 km. To see the impact of the ageostrophic moisture transport on PRE, we conducted a sensitivity experiment where the model moisture in middle and upper levels over the sea off the south coast of western Japan was reduced. Precipitation over western Japan was decreased about 30% when the contributions in moisture fluxes by ageostrophic winds were removed. This result suggests that the northward ageostrophic winds associated with a TC enhance PRE by moistening the middle and upper atmosphere.

著者

Narihiro Orikasa Atsushi Saito Katsuya Yamashita Takuya Tajiri Yuji Zaizen Tzu-Hsien Kuo Wei-Chen Kuo Masataka Murakami

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.212-219, 2020 (Released:2020-11-05)

参考文献数

31

被引用文献数

2

---

Since March 2012, multi-year ground-based observation of atmospheric aerosol particles has been carried out in Tsukuba, Japan to characterize the aerosol particle number concentrations (NCs), air mass origin relevance, and specifically, their cloud condensation nuclei (CCN) and ice nucleating particle (INP) characteristics. The CCN NCs at any water supersaturation (SS) exhibit strong seasonality, being higher in winter and lower in summer; this pattern is similar in the polluted urban environment in East Asia and contrary to that in the Pacific coastal region. The hygroscopicity (κ) is generally high in early autumn and low in early summer, likely due to the seasonal difference of synoptic-scale systems. In contrast, the INP NCs and ice nucleation active surface site density (ns) at defined temperature (−15 to −35°C) and SS (0%-5%) lack clear seasonal influence. The average INP NCs and ns in this study were comparable at warmer temperatures and approximately one order of magnitude lower at colder temperatures, compared with those in other urban locations under limited dust impact. Moreover, the ns values were one to four orders of magnitude lower and exhibited weaker temperature dependence than previous parameterizations on mineral dust particles.

著者

Kyosuke Kawano Ryoko Oda Atsushi Inagaki Makoto Nakayoshi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.192-197, 2020 (Released:2020-10-29)

参考文献数

23

---

The thermal stress along a marathon course in Tokyo is evaluated using a radiation balance model. The wet-bulb globe temperatures (WBGTs) for runners and spectators are calculated based on the surrounding building and tree geometries using the Solar LongWave Environmental Irradiance Geometry model. Analysis is conducted in terms of summer days in August 2018, which was during the hottest summer in the past 5 years. The WBGT classification for runners along the outward leg (until around 14 km) reaches the “Warning” level (WBGT = 26.5°C) despite of the many shadows on the street in the early morning (until 0645 JST). The WBGT increases around the Imperial Palace because the road has a sky view factor of over 95%, and no obstacles to make shadows on the street at around 0750 JST. The WBGT classification for runners reaches the level of “Severe warning”. For spectators, the difference of average WBGT from the runners are about 0.1°C although the difference could be significant locally due to partial shading on a road side.

著者

Hiroshi G. Takahashi Takuya Yamazaki

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.206-211, 2020 (Released:2020-11-04)

参考文献数

15

被引用文献数

2

---

This study investigated the impact of sea surface temperature (SST) on a snowfall event of late January 2018 on Kanto, Honshu, Japan, associated with an extratropical cyclone (south-coast cyclone) along the Pacific side, during the Kuroshio large meandering period by a regional atmospheric model. We addressed SST impacts on the snowfall event under almost the same synoptic-scale conditions, such as extratropical cyclone, in a framework of lateral boundary forcing. We conducted control experiments (KLM) with SST of the Kuroshio large meandering, and sensitivity experiments (NKLM) prescribed non-Kuroshio large meandering SSTs. Observational results showed that SST anomalies south of Tokai, and east of northern Kanto and Tohoku could be candidates to modify a snowfall event. As simulated results, timings of snowfall and precipitation associated with the extratropical cyclone was reproduced. Unlike what has been suggested, the SST impact south of Tokai on snowfall was not clear. However, the SST east of northern Kanto and Tohoku showed a significant impact. This impact was explained by southward advection of modified air-mass from east of northern Kanto and Tohoku. Additional sensitivity experiments supported this result. This study implies the importance of the SST anomaly east of northern Kanto and Tohoku for snowfall in Tokyo.

著者

Mikiko Fujita Tatsuya Fukuda Iwao Ueki Qoosaku Moteki Tomoki Ushiyama Kunio Yoneyama

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.16A-004, (Released:2020-10-13)

被引用文献数

4

---

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 positioning and converted to PWV with ASV surface meteorological data. The GPS-PWV was in agreement with the PWV obtained from radiosondes, with a root mean square error of 3.02 mm and a mean difference of 0.16 mm. A similar accuracy was found in a comparison of GPS-PWV with satellite-based microwave measurements. In anticipation of real-time monitoring applications, PWV was also estimated using real-time clock and orbit data. These estimates were in agreement with the post-processing values. High-resolution temporal observations of PWV over the open ocean made possible by ASV technology could greatly improve our understanding of the rapid variations of developing convective systems.

著者

Kyosuke Kawano Ryoko Oda Atsushi Inagaki Makoto Nakayoshi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-033, (Released:2020-09-10)

---

The thermal stress along a marathon course in Tokyo is evaluated using a radiation balance model. The wet-bulb globe temperatures (WBGTs) for runners and spectators are calculated based on the surrounding building and tree geometries using the Solar LongWave Environmental Irradiance Geometry model. Analysis is conducted in terms of summer days in August 2018, which was during the hottest summer in the past 5 years. The WBGT classification for runners along the outward leg (until around 14 km) reaches the “Warning” level (WBGT = 26.5°C) despite of the many shadows on the street in the early morning (until 0645 JST). The WBGT increases around the Imperial Palace because the road has a sky view factor of over 95%, and no obstacles to make shadows on the street at around 0750 JST. The WBGT classification for runners reaches the level of “Severe warning.” For spectators, the difference of average WBGT from the runners are about 0.1°C although the difference could be significant locally due to partial shading on a road side.

著者

Kazuo Saito Takumi Matsunobu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-034, (Released:2020-09-11)

被引用文献数

5

---

Heavy rainfalls often occur when a tropical cyclone (TC) exists on the sea off the south coast. These pre-typhoon rainfalls (PRE) is associated with the northward moisture transport ahead of the TC. In this paper, we examine the northward moisture transport by the ageostrophic winds associated with typhoon T0918 (Melor) and its impact on PRE. According to a numerical simulation conducted in the previous study (Saito 2019), we analyzed the northward moisture fluxes by reproduced geostrophic and ageostrophic winds. Although the southerly ageostrophic winds are dominant mainly in the upper levels, the ageostrophic winds contribute to enhance the poleward water vapor transport for the upper and middle levels above 3 km.To see the impact of the ageostrophic moisture transport on PRE, we conducted a sensitivity experiment where the model moisture in middle and upper levels over the sea off the south coast of western Japan was reduced. Precipitation over western Japan was decreased about 30% when the contributions in moisture fluxes by ageostrophic winds were removed. This result suggests that the northward ageostrophic winds associated with a TC enhance PRE by moistening the middle and upper atmosphere.

著者

Narihiro Orikasa Masataka Murakami Takuya Tajiri Yuji Zaizen Taro Shinoda

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-032, (Released:2020-08-28)

被引用文献数

2

---

Aircraft observations were conducted over the eastern mountainous areas of the United Arab Emirates (UAE) in September 2017 to characterize the microphysical properties of diurnal convective clouds. Aerosol particle and cloud condensation nuclei (CCN) measurements indicate that the air mass had a continental nature, resulting in high cloud droplet concentrations of 600-800 cm−3. Two case studies were undertaken to obtain the vertical profiles of hydrometeors up to the cloud top. The ice particle number concentrations in the updraft core were a few particles L−1, which is similar to the primary ice nucleating particle (INP) number concentrations estimated from immersion freezing of high concentration dust particles in the convectively mixed boundary layer. The ice particle number concentrations were several tens of particles L−1 outside the updraft core in the upper levels. INP measurements and the observed cloud microphysical structure suggest that drizzles, frozen via the immersion freezing nucleation of dust particles, formed graupel embryos and ice particles, with concentrations of one to two orders of magnitude greater than those of the primary INPs, which may be generated via secondary ice production and/or ice particle accumulation from primary ice nucleation in clouds with relatively warm cloud top temperatures (approximately −12°C).

著者

Sheau Tieh Ngai Hidetaka Sasaki Akihiko Murata Masaya Nosaka Jing Xiang Chung Liew Juneng Supari Ester Salimun Fredolin Tangang

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-023, (Released:2020-06-25)

被引用文献数

9

---

The Non-hydrostatic Regional Climate model (NHRCM) was used in simulating the present and future rainfall climate over Malaysia under the RCP8.5 scenario in this study. Simulation and projection from 1979 to 2002 for present day and 2070 to 2100 for the end of century were conducted over the Malaysia. The 20 km resolution MRI-AGCM3.2 model simulation from Meteorological Research Institute, MRI was used as boundary conditions. The objective of this study was to estimate the extreme rainfall projections in Malaysia at 5 km of resolution during the November to February period, representing the northeast monsoon season. Overall, the model was capable to simulate the historical rainfall climatology and distribution, but model tended to underestimate high rainfall frequency and mean rainfall intensity in Malaysia. However, compared with simulations at 25 km, added values have been shown at 5 km resolution. Based on the NHRCM05 simulations, a number of hotspots have been identified with significant projected increases up to 80% for the extreme rainfall indices (R20mm, RX1day, R95pTOT and R99pTOT), 30% increases in mean rainfall intensity (SDII) and 20% for consecutive dry days indices (CDD).

著者

Takafumi Miyasaka Hiroaki Kawase Tosiyuki Nakaegawa Yukiko Imada Izuru Takayabu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

pp.2020-022, (Released:2020-06-22)

被引用文献数

14

---

Heavy precipitation in Japan is caused by various phenomena, such as tropical cyclones and the Baiu front, and shows regional-scale variation. Here we investigate extremely heavy precipitation events exceeding the 100-year return period in the Kanto area and future projections of such events using large ensemble climate simulations for periods of several thousand years. To understand these extreme events, associated sea level pressure anomalies over Japan and the surrounding region are classified into four clusters. These cluster means are characterized by (1) a strong anomalous cyclone, (2) a weak anomalous cyclone, (3) an anomalous cyclone accompanied by an anomalous anticyclone to the north, and (4) an anomalous anticyclone to the north. The cluster with a strong anomalous cyclone is accompanied by widely distributed heavy precipitation, and its area-averaged precipitation is predicted to be more enhanced under global warming than that of other clusters, partly because of an increase in the strength of strong tropical cyclones approaching Kanto. The cluster dominated by an anomalous anticyclone is characterized by localized heavy precipitation in the plains area. The relative frequency of this cluster will increase, whereas that of other clusters will decrease under global warming.