著者

Hideo Shiogama Noriko N. Ishizaki Naota Hanasaki Kiyoshi Takahashi Seita Emori Rui Ito Toshiyuki Nakaegawa Izuru Takayabu Yasuaki Hijioka Yukari N. Takayabu Ryosuke Shibuya

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17, pp.57-62, 2021 (Released:2021-04-03)

参考文献数

20

被引用文献数

1 16

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Climate change impact assessment studies often use future projections of only a few global climate models (GCMs) due to limited research resources. Here we develop a novel method to select a small subset of GCMs that widely capture the uncertainty range of large ensemble. By applying this method, we select a subset of five GCM projections from the Coupled Model Intercomparison Project Phase 6 (CMIP6) ensemble for impact and adaptation studies in Japan. At first, we omit GCMs whose global warming projections have been evaluated to be overestimated in the recent literature. Then, we select a subset of five GCMs that widely captures the uncertainty ranges for 8 climate variables and have good performances in present-climate simulations. These selected GCM simulations will be used to provide better climate scenarios for impact and adaptation studies than those in the previous impact assessment project.

著者

S. Manabe

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.35, no.6, pp.311-326, 1957-12-25 (Released:2007-10-19)

参考文献数

20

被引用文献数

69 71

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Japan Sea is generally considered to be one of the places where the most rapid airmass transformation takes place in winter season.As it is surrounded by the dense network of radiosonde and surface observation stations, quantitative investigation about the modification of airmass is possible.Selecting the period of a typical continuous outburst of cold air from 20 Dec.'54 to 3 Jan.'55 during which the air-sea temperature difference exceeded 10°C, we computed the integrated netflux divergence of enthalpy and water vapor and the vertical transport of them at the standard levels in the lower half of the troposphere, and further estimated the amount of heating and cooling due to radiation and condensation.Then, based upon the balance requirement, the amount of heat or water vapor supplied from the sea to the atmosphere was obtained.According to the results of above computations, it is concluded that the amount of supplied heat is as much as 1000ly/day in such a typical unstable situation, and is 2.3 times as large as that of supplied latent heat in spite of the fact that mean Bowen's ratio expected from mixing length theory was nearly equal, to unity.Finally, for several periods when no remarkable cyclone passed over the Japan Sea, the amount of evaporation computed by the scheme above-mentioned are compared with the results obtained by use of climatological evaporation equation after Jacobs.

著者

野田 彰 時岡 達志

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.67, no.6, pp.1057-1069, 1989 (Released:2007-10-19)

参考文献数

27

被引用文献数

37 43

著者

Qoosaku Moteki

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15A, pp.37-42, 2019 (Released:2019-07-10)

参考文献数

21

被引用文献数

13

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Heavy rain in western Japan was broadly induced by the stagnation of the Baiu front during 5-7 July 2018. This study hypothesizes that cold air advection over the Sea of Japan intensified by Typhoon Prapiroon (Typhoon No. 7) was one of the triggering factors for the formation process of the Baiu front over western Japan. Typhoon Prapiroon passed over the Sea of Japan on 4 July and became extratropical at approximately 40°N on 5 July. During its passage, the strong southward pressure gradient force to the north of Typhoon Prapiroon broke down the convergence line of the Baiu front that remained at approximately 45°N before 4 July and thick cold air from the Okhotsk High flowed over the Sea of Japan. The Okhotsk High expanded toward the Sea of Japan and enhanced cold air advection to the north of western Japan. As a result, the Baiu front was stationary at approximately 35°N after 5 July. In addition, the westerly jet in the east of an upper-level trough deepened along the typhoon track was associated with the adiabatic component of the ascending motion over the isentropic upslope and was suggested to contribute to the maintenance of Baiu frontal convection.

著者

DUEBEN Peter D. WEDI Nils SAARINEN Sami ZEMAN Christian

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-016, (Released:2020-03-17)

被引用文献数

2 24

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Global simulations with 1.45 km grid-spacing are presented that were performed with the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). Simulations are uncoupled (without ocean, sea-ice or wave model), using 62 or 137 vertical levels and the full complexity of weather forecast simulations including recent date initial conditions, real-world topography, and state-of-the-art physical parametrizations and diabatic forcing including shallow convection, turbulent diffusion, radiation and five categories for the water substance (vapour, liquid, ice, rain, snow). Simulations are evaluated with regard to computational efficiency and model fidelity. Scaling results are presented that were performed on the fastest supercomputer in Europe - Piz Daint (Top 500, Nov 2018). Important choices for the model configuration at this unprecedented resolution for the IFS are discussed such as the use of hydrostatic and non-hydrostatic equations or the time resolution of physical phenomena which is defined by the length of the time step. Our simulations indicate that the IFS model — based on spectral transforms with a semi-implicit, semi-Lagrangian time-stepping scheme in contrast to more local discretisation techniques — can provide a meaningful baseline reference for O(1) km global simulations.

著者

Saori Nakashita Takeshi Enomoto

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.17A, no.Special_Edition, pp.33-37, 2021 (Released:2021-04-20)

参考文献数

14

被引用文献数

2

---

The predictability of Typhoon Hagibis in October 2019 is examined with ensemble forecasts from four major operational numerical weather prediction centers. From six to four days before the landfall, the forecast from the Japan Meteorological Agency was the best among the four centers. However, the error increased sharply three days before the landfall. Consistent with the westward track error, a northwestward bias is found in the environmental winds. The ensemble sensitivity analysis for the landing region indicates a large sensitivity to a ridge located to the southeast of the typhoon. The member with the largest track error has perturbations that act to weaken the ridge. A low-pressure disturbance to the southeast of the ridge is found to migrate westward faster than the member with the smallest track error. Therefore, the typhoon is advected westward by the easterlies associated with the low. These results indicate a significant influence of the tropical disturbance on the predictability of Hagibis.

著者

HUANG Xiaogang PENG Xudong FEI Jianfang CHENG Xiaoping DING Juli YU Dandan

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2021-008, (Released:2020-11-19)

被引用文献数

19

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This study systematically evaluates the accuracy, trends and error sources for western North Pacific tropical cyclone intensity forecasts between 2005 and 2018. The study uses homogeneous samples from TC intensity official forecasts issued by the China Meteorological Administration (CMA), the Joint Typhoon Warning Center (JTWC), and the Regional Specialized Meteorological Center Tokyo-Typhoon Center (RSMC-Tokyo). The TC intensity forecast accuracy performances are: 24-48 h, JTWC > RSMC-Tokyo > CMA; 72 h, JTWC > CMA > RSMC-Tokyo; and 96-120 h, JTWC > CMA. Improvements in TC intensity forecasting are marginal but steady for all the three centers. The 24-72 h improvement rate is approximately 1-2 % yr−1. The improvement rates are statistically significant at the 95 % level for almost half of the verification times from 0-120 h. The three centers tend to overestimate weak TCs over the northern South China Sea, but strong TCs are sometimes underestimated over the area east of the Philippines. The three centers generally have higher skill scores associated with forecasting of rapid weakening (RW) events than rapid intensification (RI) events. Overall, the three centers are not skillful in forecasting RI events more than three days in advance. Fortunately, RW events could be forecasted five days in advance with an accuracy order of CMA > RSMC-Tokyo > JTWC.

著者

Seika Tanji Masaru Inatsu

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15, pp.32-36, 2019 (Released:2019-02-13)

参考文献数

31

被引用文献数

2 4

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Blowing snow potential is diagnosed for typical cases around Sapporo, Japan, as snow concentration and visibility based on dynamically downscaled data with 1-km resolution. The results are consistent with the blowing-snow records on time and place of traffic disruption, when the dynamical downscaling (DDS) reproduced wind speed well for a case. The diagnosis with mesoscale model analysis with 5-km resolution does not reproduce the blowing snow events in most area, however. Hence, the DDS potentially, not perfectly, adds the value to estimate blowing snow potential, despite a large scale-gap from an explicit representation of small-scale turbulence related to blowing snow. Sensitivity tests clarify that blowing snow requires strong wind and freezing temperature at the surface.

著者

Yu Someya Yukio Yoshida Shamil Maksyutov

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.157-161, 2020 (Released:2020-08-25)

参考文献数

33

被引用文献数

2

---

Although wetlands are the largest natural source of atmospheric methane, the amount and variability of methane emissions from wetlands still have large uncertainty. We investigated the local growth rate of the column-averaged methane dry air mole fraction (XCH4) in Siberia where wetlands are widely abundant using 11-year (2009-2019) Greenhouse gases Observing SATellite (GOSAT) data. While the mean growth rate during the summer from the GOSAT observations is 7.2 ppb yr−1 globally, that in West Siberia is 8.4 ppb yr−1. In particular, the growth rates in West Siberia after 2013 is much larger in July and August than in the other months. Moreover, the growth of XCH4 in West Siberia appears to larger than in the other boreal areas. These results imply that methane emissions from wetlands in West Siberia increased during the summer in recent several years.

著者

YAMAGUCHI Munehiko MAEDA Shuhei

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-068, (Released:2020-08-27)

被引用文献数

15

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Global warming already affects weather and climate worldwide; accordingly, various studies have been conducted to understand the effects of climate change on tropical cyclones (TCs). The translation speed of a tropical cyclone is a particularly important feature, as a slower translation speed lengthens the duration of a cyclone's impact. Here, on the basis of observational data, we report that tropical cyclone translation speeds in the middle latitudes of the western North Pacific basin have significantly decreased during September over the last 40 years. Historical model simulations with and without observational global warming trends reveal two main factors responsible for translation speed slowdown: natural decadal climate variabilities (such as the Pacific Decadal Oscillation) and global warming. Both factors produce an anticyclonic anomaly in the westerly jet over western Japan; this anomaly relaxes the latitudinal geopotential height gradient, weakening the environmental synoptic winds by which tropical cyclones are steered. Furthermore, model simulations for a future warmer climate show that global warming further reduces the steering flows, leading to more slowly-moving TCs in autumn in the future.

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

vol.16, pp.185-191, 2020 (Released:2020-10-17)

参考文献数

22

被引用文献数

2

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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

SONG Hwan-Jin KIM Sunyoung ROH Soonyoung LEE Hyesook

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-044, (Released:2020-06-02)

被引用文献数

6

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This study compares the regional characteristics of heavy rain clouds in terms of Cloud Top Height (CTH) and Storm Height (SH) from long-term Tropical Rainfall Measuring Mission (TRMM) observations. The SH is derived from Precipitation Radar reflectivity and the CTH is estimated using Visible and InfraRed Scanner brightness temperature (10.8 μm) and reanalysis temperature profiles. As the rain rate increases, the average CTH and average SH increase, but by different degrees in different regions. Heavy rainfall in continental rainfall regimes such as Central Africa and the United States is characterized by high SH, in contrast to oceanic rainfall regions such as the northwestern Pacific, Korea, and Japan; the increase of atmospheric instability in dry environments is interpreted as a mechanism of continental floods. Conversely, heavy rain events in Korea and Japan occur in a thermodynamically near-neutral environment with large amounts of water vapor; these are characterized by the lowest CTH, SH, and ice water content. The northwestern Pacific exhibits the lowest SH in humid environments, similar to Korea and Japan; however, this region also characteristically exhibits the highest convective instability condition as well as high CTH and CTH–SH values, in contrast to Korea and Japan. The observed CTH and SH characteristics of heavy rain clouds are expected to be useful for the evaluation and improvement of satellite-based precipitation estimation and numerical model cloud parameterization.

著者

TSUJI Hiroki YOKOYAMA Chie TAKAYABU Yukari N.

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-045, (Released:2020-06-02)

被引用文献数

35

---

Precipitation characteristics and environment are compared between two rainfall events in Japan: the July 2018 heavy rainfall event (2018 case) and the 2017 Northern Kyushu rainfall event (2017 case). Both events occurred in the later stage of the Baiu season, after the passage of a tropical cyclone, south of a subtropical jet and to the front side of an upper tropospheric trough. However, contrasting precipitation properties and environments are observed between these cases. In the 2018 case, long-lasting heavy precipitation was observed over a large area with moderately tall precipitation systems. Environment was stable and moist compared with the climatology. A deep trough over the Korean Peninsula played a role to prepare the environment favorable for organizing precipitation systems through moistening of mid-troposphere by quasi-geostrophic dynamically forced ascent. In contrast, in the 2017 case, a short-term intense precipitation was observed over a small area with exceptionally tall precipitation systems. The environment was unstable and moist compared with the climatology but was dryer than the 2018 case. In this case, a shallow trough over the Korean Peninsula destabilized the atmosphere via associated high-altitude cold air.  The observed contrast of characteristics between the 2018 and 2017 cases is like that found between composites of extreme rainfall events and extremely tall convection events included in the previous statistical study by Hamada and Takayabu (2018, doi:10.1175/JCLI-D-17-0632.1). Temperature anomalies and specific humidity anomalies from climatological values in the 2018 and 2017 cases are several times as large as those in the composites of the extreme events although the previous study analyzed the uppermost 0.1 % of extreme events. This result means that the 2018 case is an extreme among the extreme rainfall events and the 2017 case corresponds to an extreme event of the extremely tall convection events.

著者

Shuhei Matsugishi Hiroaki Miura Tomoe Nasuno Masaki Satoh

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16A, no.Special_Edition, pp.12-18, 2020 (Released:2020-06-27)

参考文献数

38

被引用文献数

6

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We show that a modification to the latent heat flux (LHF) formulation in Non-hydrostatic Icosahedral Atmospheric Model (NICAM) impacts the representation of a Madden–Julian oscillation (MJO) event during the Pre-Years of the Maritime Continent (Pre-YMC) field campaign in 2015. First, we compare the LHFs computed by the standard NICAM setting with those estimated from the ship observation during Pre-YMC. In this comparison, the NICAM LHF is smaller than observation in the low wind speed region and larger in the high wind speed region. Consequently, the MJO signal weakens when it passes over the Maritime Continent (MC). Next, sensitivity experiments are conducted with a modification to the threshold minimum wind speed in the bulk formula, to enhance the LHFs in the low wind speed region. With this modification, propagation of the MJO is better simulated over the MC, although a bias still remains without corrections in the high wind speed regions. This result indicates that increasing the LHF in the low wind speed region likely contributes to a more effective accumulation of moisture over the eastern MC region and consequently allows the MJO to pass over the MC in the model.

著者

Hideo Shiogama Rui Ito Yukiko Imada Toshiyuki Nakaegawa Nagio Hirota Noriko N. Ishizaki Kiyoshi Takahashi Izuru Takayabu Seita Emori

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.16, pp.75-79, 2020 (Released:2020-05-01)

参考文献数

22

被引用文献数

5

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The ensemble average projections of the Coupled Model Inter-comparison Project Phase 5 (CMIP5) ensemble show future increases in shortwave radiation at the surface (SW) in Japan. We reveal that the Arctic Oscillation-like atmospheric circulation trends cause cloud cover decreases around Japan, leading to increases in the SW.In many cases, impact assessment studies use the outputs of only a few models due to limited research resources. We find that the four climate models used in the Japanese multisector impact assessment project, S-8, do not sufficiently capture the uncertainty ranges of the CMIP5 ensemble regarding the SW projections. Therefore, the impact assessments using the SW of these four models can be biased. We develop a novel method to select a better subset of models that are more widely distributed and are not biased, unlike the S-8 models.

著者

松川 哲美

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.3, no.6, pp.160-162, 1925-07-30 (Released:2009-02-05)

著者

SUI Chung-Hsiung SATOH Masaki SUZUKI Kentaroh

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-024, (Released:2020-03-01)

被引用文献数

21

---

Precipitation efficiency (PE) is a useful concept for estimating precipitation under a given environmental condition. PE is used in various situations in meteorology: to evaluate severe precipitation associated with a single storm event; as a parameter of cumulus convective parameterization; and to separate clouds and precipitation in climate projection studies. PE has been defined in several ways. In this review, we start with definitions of PE from microscopic and macroscopic perspectives, and provide estimates of PE based on observational and modeling approaches. Then, we review PE in shallow and organized deep convective systems that provide either a conceptual framework or physical constraints on representations of convection in models. Specifically, we focus on the roles of PE in cloud-radiative feedbacks to climate variability. Finally, we argue the usefulness of PE for investigating cloud and precipitation changes in climate projection studies.

著者

SEO Jaemyeong Mango LEE Hyunho MOON Sungju BAIK Jong-Jin

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2020-003, (Released:2019-10-20)

被引用文献数

3

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This study examines how upslope geometry controls aerosol effects on orographic precipitation through two-dimensional idealized simulations of orographic precipitation from shallow warm convective clouds over a bell-shaped mountain with 1-km height. A total of nine cases are simulated by considering three different prescribed aerosol number concentrations and three different windward-widths of the mountain. For a detailed representation of drop size distributions, the Weather Research and Forecasting (WRF) model that includes a bin microphysics scheme is used with a horizontal grid size of 250 m and 401 terrain-following vertical levels. A higher aerosol number concentration leads to production of more cloud droplets, inhibiting the growth of cloud droplets into raindrops in the cases with the symmetric mountain (the windward-side half-width a1 = 10 km). As a result, the total and maximum surface precipitation amounts decrease and the location of the maximum surface precipitation amount shifts downstream. The aerosol effects on orographic precipitation are more clearly seen in the cases with the narrow windward-width (a1 = 5 km) compared to the cases with the symmetric mountain and the wide windward-width (a1 = 20 km). In the cases with the narrow windward-width, the steep upslope generates strong convection with a short advection timescale (∼ 600 s), resulting in more precipitation being concentrated over a narrow area of the mountain downslope compared to the cases with the symmetric mountain and the wide windward-width. On the other hand, in the cases with the wide windward-width, the gentle upslope generates weak convection with a sufficiently long advection timescale (∼ 2400 s), so that a large portion of liquid drops precipitates out on the wide mountain upslope before reaching the peak.

著者

Nobuo Sugimoto Yoshitaka Jin Atsushi Shimizu Tomoaki Nishizawa Keiya Yumimoto

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15, pp.257-261, 2019 (Released:2019-12-26)

参考文献数

19

被引用文献数

1 7

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Mineral dust transported from Africa and Middle East was observed with the Asian Dust and aerosol lidar observation Network (AD-Net). In March 2018, the dense Sahara dust, reported by mass media as that snow in Sochi, Russia stained into orange, was transported to Sapporo in 4 days from Sochi and observed by the lidar. In April 2015, dust from Middle East was transported to Nagasaki passing across the Taklamakan desert. Dust source areas and transport paths were studied with the global aerosol transport model MASINGAR mk-2 separately calculated for different dust sources regions. The results showed that dust from Sahara and Middle East was transported to East Asia and sometimes mixed with dust from the Gobi desert and the Taklamakan desert. The analysis of recent AD-Net data after 2015 showed such long-range transport cases were observed every year in March or April. The transport path often led over the Caspian Sea, Kazakhstan, and Russia. Sahara dust transported north and reached around the Black Sea was transported long range by strong westerly in springtime.

著者

Tetsuya Takemi

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.15, pp.125-131, 2019 (Released:2019-05-30)

参考文献数

32

被引用文献数

23

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This study investigated the impacts of global warming on extreme rainfall produced by a slow-moving typhoon by conducting pseudo-global warming (PGW) experiments. We examined Typhoon Talas (2011) that caused long-lasting heavy rainfall exceeding 2000 mm over the Kii Peninsula. The experiments successfully captured the track and translation speed of the actual typhoon, which enabled to quantitatively assess the climate change impacts. The PGW experiments indicated that the extreme rainfall is intensified in the future climates than in the present climate. Especially, the higher extremes of the accumulated rainfall are projected to be more severe in the future climate scenario. The analysis on the environmental factors showed that the cases with increased precipitable water lead to the increases in rainfall in future climates, despite the stabilized atmospheric conditions. Among the PGW experiments, the most increased amount of rainfall was found not to be produced by the most intensified typhoon.