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Mechanism of Secondary Eyewall Formation in Tropical Cyclones Revealed by Sensitivity Experiments on the Mesoscale Descending Inflow SOLA (IF 1.9) Pub Date : 2024-03-15 Kyohei Kasami, Masaki Satoh
An eyewall replacement cycle is often seen in tropical cyclones, when a secondary eyewall forms outside the inner eyewall, and the inner eyewall disappears. Although this cycle significantly affects the intensity of tropical cyclones, the mechanisms of secondary eyewall formation (SEF) are diverse, and most are complementary. Some studies have suggested that dry air inflow and diabatic cooling may
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Recent decelerating trends of urban warming in Japan SOLA (IF 1.9) Pub Date : 2024-03-12 Fumiaki Fujibe
Temperature trends in Japanese cities were analyzed using data at 433 stations on the AMeDAS network from April 1979 to March 2023. It was found that urban warming, defined by a temperature increase at an urban station relative to the surrounding non-urban stations, had slowed down in the latter part of the analysis period. The deceleration of urban warming was commonly found for northern, eastern
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Emergent constraints on future changes in several climate variables and extreme indices from global to regional scales SOLA (IF 1.9) Pub Date : 2024-03-12 Hideo Shiogama, Michiya Hayashi, Nagio Hirota, Tomoo Ogura
Climate change impact modelling studies often require not only mean temperature and precipitation but also other climate variables (e.g., solar radiation and wind speed) and extreme indices as input data. However, studies on observational constraints (emergent constraints) about these variables and indices are limited. Based on linearities of future climate change as functions of global warming levels
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Heavy Rainfall on the North Side of Western Japan Induced by Typhoon Lan (2023): Roles of High Sea Surface Temperature over the Sea of Japan and a Terrain-Induced Mesoscale Low SOLA (IF 1.9) Pub Date : 2024-03-05 Satoki Tsujino, Akiyoshi Wada, Teruyuki Kato
An extreme rainfall event with 48-h accumulated precipitation amounts exceeding 500 mm on the north (Japan Sea) side of western Japan occurred when Typhoon Lan (2023) approached and passed over Japan in a weak baroclinic environment. The rainfall event included two local heavy precipitation peaks. In the present study, we perform numerical simulations with a cloud-system-resolving model to investigate
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Vertical development speed of shallow radiation fog SOLA (IF 1.9) Pub Date : 2024-03-02 Rieko Y. Tanahashi, Ryota Misawa, Hirofumi Sugawara
Field observations were conducted at Ibaraki Airport, Japan, to determine the vertical development speed of shallow radiation fog. The development speed in shallow (less than several meters) fog was 3-16 cm min−1, and was slower at higher wind speeds. The speed decreased when the air above the fog layer became drier, possibly due to the mixing of the fog layer with the dry air above it. The speed data
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Three-Dimensional Structure of an Equilibrium Drop Size Distribution within a Convective System in Japan SOLA (IF 1.9) Pub Date : 2024-02-26 Takashi Unuma
This study investigated three-dimensional structure of an equilibrium drop size distribution within a convective system that spawned heavy rainfall over northern Kyushu in western Japan on 10 July 2023. Ground-based optical disdrometer observations showed that the drop size distribution shape became bimodal (the peaks are at 0.7 and 1.0 mm in diameter) and then reached an equilibrium state during the
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Typhoon Intensity Forecasts using TIFS with Pseudo Ocean Coupling SOLA (IF 1.9) Pub Date : 2024-02-23 Munehiko Yamaguchi, Norihisa Usui, Nariaki Hirose
Typhoon HAISHEN, Typhoon No. 10 in 2020, was weaker than forecasts as it moved north over the western coast of Kyushu. The typhoon intensity forecasting scheme called TIFS operated at the Japan Meteorological Agency (JMA) tended to predict HAISHEN's intensity more strongly than the observed one, resulting in large errors in JMA's operational forecasts. One possible reason for the large errors is that
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Seasonal prediction system using CFES and comparison with SINTEX-F2 SOLA (IF 1.9) Pub Date : 2024-02-23 Tomomichi Ogata, Nobumasa Komori, Takeshi Doi, Ayako Yamamoto, Masami Nonaka
In this study, we introduce a new seasonal prediction system using an atmosphere–ocean-coupled general circulation model called CFES (hereafter referred to as CFES ESPreSSO). We compare its prediction skill of the interannual variability of the surface air temperature (SAT) and precipitation anomalies with that of the SINTEX-F2 seasonal prediction system. We find that CFES ESPreSSO has a higher skill
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Semi-Continuous Measurements of Sulfate in Fine Particles in Central Japan: On High Concentration Events and Comparison with Measurement Concentrations by a Commercial Sulfate Monitor SOLA (IF 1.9) Pub Date : 2024-02-20 Koichi Watanabe, Nobuhiro Yamazaki, Motoki Takeuchi, Hiroki Matsubara, Kensuke Fukai
At a site on the Sea of Japan side of central Japan, the concentrations of ionic components in PM2.5 were measured semi-continuously for about 15 months using filter collection and ion chromatography (filter method). Continuous measurements of sulfate particles were simultaneously performed in summer and autumn using a commercial sulfate monitor (Sulfate Particle Analyzer, SPA). High concentrations
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Preliminary diagnosis of primary factors for an unprecedented heatwave over Japan in 2023 summer SOLA (IF 1.9) Pub Date : 2024-02-15 Kazuto Takemura, Hirotaka Sato, Akira Ito, Takafumi Umeda, Shuhei Maeda, Masayuki Hirai, Yuko Tamaki, Hirokazu Murai, Hiroshi Nakamigawa, Yukari N. Takayabu, Hiroaki Ueda, Ryuichi Kawamura, Youichi Tanimoto, Hiroaki Naoe, Masami Nonaka, Toshihiko Hirooka, Hitoshi Mukougawa, Masahiro Watanabe, Hisashi Nakamura
In summer 2023, record-high temperatures were observed in many parts of the Northern Hemisphere, including Japan, where summer-mean temperature was the highest over the last 126 years. Under an unprecedented heatwave in late July through September, record-high temperatures were successively observed particularly over northern and eastern Japan. The late-July heatwave is attributable primarily to the
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Recent Global Distribution of Aridity Index and Land Use in Arid Regions SOLA (IF 1.9) Pub Date : 2024-02-15 Reiji Kimura, Masao Moriyama
Drylands, which occupy 41% of Earth's land area, have large effects on Earth's climate via land-atmosphere interactions, and simulations of future climate indicate that drylands will be very sensitive to climate changes associated with global warming. Monitoring of drylands is therefore necessary to help guide sustainable development in drylands and to protect the global environment. This study examined
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The Impacts of East Siberian Blocking on the Development of the JPCZ SOLA (IF 1.9) Pub Date : 2024-02-07 Akira Yamazaki, Shin Fukui, Shiori Sugimoto
Ensemble dynamical downscaling experiments were performed to investigate the influence of East Siberian blocking on a heavy snowfall event that occurred over Fukui City, Japan, in early February 2018 and was associated with the development of the Japan Sea Polar airmass Convergence Zone (JPCZ). The downscaling experiments simulated the enhancement of the East Asian cold air stream and its flow along
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Evaluations of Actual and Adjusted Wind–Pressure Relationship of Tropical Cyclone Using Aircraft-Assisted Best Track Data SOLA (IF 1.9) Pub Date : 2024-02-01 Sho Arakane, Takeshi Horinouchi
The relationship between maximum sustained wind speed (Vmax) and minimum sea level pressure (Pmin) of tropical cyclones (TC), which is called the wind–pressure relationship (WPR), is investigated by using best track data in which aircraft observations are used. On average, for given Vmax (Pmin), Pmin (Vmax) varies by 8.5 hPa (11.0 kt) between the 25th and 75th percentiles, and it varies by 17.1 hPa
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Shallow Coastal Water Responses During the Near Landfall Intensification of Tropical Cyclones in the South China Sea SOLA (IF 1.9) Pub Date : 2024-02-02 Chunyi Xiang, Hironori Fudeyasu, Udai Shimada, Ryuji Yoshida
Shallow coastal seawater response during the passage of near-landfall intensification (NLI) tropical cyclones (TCs) and non-NLI TCs was examined using oceanic and atmospheric reanalysis data and observations. The sea surface temperature ahead of the NLI-TC track is maintained or even increases when NLI-TC is approaching the land. The magnitude of the wind stress, which play an important role in the
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The SOLA Award in 2023 SOLA (IF 1.9) Pub Date : 2024-02-01 Tetsuya Takemi
The Editorial Committee of Scientific Online Letters on the Atmosphere (SOLA) presents the SOLA Award to one or two outstanding papers published each year. We are pleased to announce that The SOLA Award in 2023 will be given to the paper by Drs. Sachie Kanada and Akira Nishii, entitled "Observed Concentric Eyewalls of Supertyphoon Hinnamnor (2022)" (Kanada and Nishii 2023) and to the paper by Dr. Kenji
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The Environment and Precipitation Characteristics of Widespread Extreme Rainfall Events during the Akisame Season SOLA (IF 1.9) Pub Date : 2024-01-31 Aiko Narita, Yukari N. Takayabu
This study investigates the precipitation characteristics and disturbances of widespread heavy rainfall during the Akisame using meteorological data from the Japanese 55-year Reanalysis, precipitation data from the Automated Meteorological Data Acquisition System (AMeDAS), the Global Satellite Mapping of Precipitation (GSMaP) and the Global Precipitation Measurement (GPM) data. First, in the climatological
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Microphysical Characteristics of Warm Convective Precipitation in Tokyo SOLA (IF 1.9) Pub Date : 2024-01-16 Ryohei Misumi, Yasushi Uji, Takeshi Maesaka
It is generally considered that warm rain is less likely to occur in urban areas where the air is polluted. However, heavy precipitation from shallow convective clouds is occasionally reported in Tokyo. In this study, we observed microphysical characteristics of warm convective precipitation in Tokyo on 19-20 August 2019 using an X-band polarimetric radar, a Ka-band radar, a cloud droplet spectrometer
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Contribution of Shallow Convection to the Localization of a Band-Shaped Area of Heavy Precipitation on 4 July 2020 SOLA (IF 1.9) Pub Date : 2024-01-01 Mikio Nakanishi
On 4 July 2020, a quasi-stationary band-shaped area of heavy precipitation occurred near the center of Kyushu, Japan. The contribution of shallow convection to the localization of the precipitation area is examined using the Weather Research and Forecasting model. Two turbulent transport schemes, the Yonsei University scheme and the Mellor–Yamada–Nakanishi–Niino (MYNN) scheme, are selected. Simulations
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Land surface physics-based downscaling approach for agricultural meteorological prediction: Applicability for tropical-monsoon region, the Red River Delta, Vietnam SOLA (IF 1.9) Pub Date : 2023-11-21 Mau Nguyen-Dang, Quang-Van Doan, Duong-Trịnh Hoang, Thanh-Hung Nguyen, Do Ngoc Khanh, Duong Cao Phan, Tam Tran-Thi, Hieu-Nguyen Van, Tuan Bui-Minh
This study represents a pioneering effort to establish a downscaling framework named “land-surface-physics-based downscaling” (LSP-DS) for agricultural meteorological prediction in the tropical-monsoon region of the Red River Delta, Vietnam. The primary focus of this article is to evaluate the performance of LSP-DS on meteorological variables, specifically temperature and humidity. In details, LSP-DS
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The Role of Sea-Surface Conditions in Southern-Hemisphere Polar Vortex Strength and Associated Wave Forcing Revealed by a Multi-member Ensemble Simulation with the Chemistry–Climate Model SOLA (IF 1.9) Pub Date : 2023-11-17 Yousuke Yamashita, Hideharu Akiyoshi, Makoto Inoue
The dynamical response of the southern hemisphere stratosphere to the ocean-surface conditions in 2002 and 2019, when exceptional sudden stratospheric warming (SSW) events occurred, was examined through the chemistry–climate model and experiments with 1,000 ensemble members using the sea-surface temperature (SST) and sea-ice conditions. Planetary waves propagating from the troposphere to the stratosphere
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Diurnal SST warming and the boreal summer intraseasonal oscillation in the Philippine Sea: contrasts between early and late summer SOLA (IF 1.9) Pub Date : 2023-11-01 Ayako Seiki, Akira Nagano, Ning Zhao, Iwao Ueki, Satoru Yokoi
The relationship between diurnal fluctuations of sea surface temperature (SST) in the Philippine Sea and the boreal summer intraseasonal oscillation (BSISO) and its difference between early and late summer are investigated using four-year (2017-2020) data of a moored buoy deployed at 137°E, 13°N. A strong diurnal cycle of SST is observed frequently during convectively suppressed phases of the BSISO
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Impact of the SST-front on subseasonal predictions of North Atlantic winter circulation using the JMA operational seasonal prediction system SOLA (IF 1.9) Pub Date : 2023-10-25 Yukimasa Adachi, Hiroaki Naoe, Yutaro Kubo
This study evaluates the impact of the mid-latitude oceanic front (MOF) on forecasts using the latest Japan Meteorological Agency seasonal prediction system. We focus on subseasonal predictions of the North Atlantic winter circulation by comparing hindcast experiments with different ocean model resolutions from 1991 to 2020. We find that the higher resolution of sea surface temperatures (SSTs) in the
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Snow melting estimate in the Jozankei Dam basin based on snowpack simulation SOLA (IF 1.9) Pub Date : 2023-10-08 Yoko Taniguchi, Yuta Katsuyama, Masaru Inatsu, Takashi Yamada
A physical snowpack model was forced by observed meteorological data to map the snow melting distribution over the Jozankei Dam basin, Sapporo, Japan. First, the snowpack model experiment forced by radar precipitation reasonably reproduced the snow environment in the basin, although it underestimated the snow depth in the northern area. Second, the map of the basin showed that the average difference
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Mass-Extinction Conversion Factor (MECF) over the Gobi Desert by a Tethered-balloon-based OPC and a Ceilometer SOLA (IF 1.9) Pub Date : 2023-10-03 Kenji Kai, Kei Kawai, Kazuma Ohara, Yuki Minamoto, Yoshitaka Jin, Teruya Maki, Jun Noda, Tatsuo Shiina, Enkhbaatar Davaanyam
The mass concentration of Asian dust in the atmosphere is an essential parameter of the atmospheric environment in East Asia. In April 2016, we conducted simultaneous observations using an optical particle counter (OPC) installed on a tethered balloon and a ceilometer in the Gobi Desert. We estimated the mass-extinction conversion factor MECF (gm−2) from the relationship between the dust extinction
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Development of a new particle imaging radiosonde with particle fall velocity measurements in clouds SOLA (IF 1.9) Pub Date : 2023-09-26 Kenji Suzuki, Yurika Hara, Takuji Sugidachi, Kensaku Shimizu, Masatomo Fujiwara
A new particle imaging radiosonde “Rainscope” has been developed, and for the first time, particle fall velocity measurement functionality was added to a balloon-borne device. Rainscope can capture a clear still image of precipitation particles in a cloud when they interrupt an infrared beam, using a CMOS camera equipped with an electronic shutter. It can also record the time when a particle passes
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Regional extreme precipitation events in wintertime Japan facilitated by East-Asian large-scale flow patterns SOLA (IF 1.9) Pub Date : 2023-09-16 Takumi Matsunobu, Julian F. Quinting, Christian M. Grams, Mio Matsueda
The statistical and dynamical relationships between regional extreme precipitation events (EPEs) during wintertime in five Japanese regions and East-Asian synoptic weather patterns are addressed. 4 Two of the five weather patterns, the southerly flow (SF) and low pressure (LP), are associated with about 50% of EPEs in all the regions. A regional dependency is found, with SF being more likely to cause
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SolaCam: A Deep Learning Model for Solar Radiation Estimation Using Consumer Cameras SOLA (IF 1.9) Pub Date : 2023-09-13 Daisuke Sugiyama, Ryo Onishi, Hironori Fudeyasu
This study proposes a deep learning approach called SolaCam to accurately estimate solar radiation from the images captured by cameras. The proposed SolaCam performs deep learning by utilizing both image features and theoretical maximum solar radiation that vary with time and location. The trained model is capable of accurately estimating solar radiation on the ground surface from sky images captured
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Evaluation of black carbon concentration levels and trends in East Asia from CMIP6 climate models: Comparison to long-term observations in Japan and biases due to Chinese emissions SOLA (IF 1.9) Pub Date : 2023-09-09 Kohei Ikeda, Hiroshi Tanimoto, Yugo Kanaya, Fumikazu Taketani, Atsushi Matsuki
We evaluated the mass concentration levels and long-term trends of black carbon (BC) in the historical and future scenario simulations using 12 climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) for East Asia, the region with the largest anthropogenic emissions. By comparing them with surface observations at two regionally representative sites, Fukue and Noto, for the period
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Particulate Matter Prediction and Shapley Value Interpretation in Korea through a Deep Learning Model SOLA (IF 1.9) Pub Date : 2023-09-05 Youngchae Kwon, Seung A An, Hyo-Jong Song, Kwangjae Sung
This study collected and analyzed data to predict particulate matter (PM) concentrations in Korea at regular intervals. Automated synoptic observation system data, real-time atmospheric observation data from AirKorea, and Geostationary Korea Multipurpose Satellite – 2A data were used. We also used deep learning, which is useful for PM predictions. The deep learning model used a neural network (NN)
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An attempt to estimate differential reflectivity bias using volume scan dataset obtained by C-band polarimetric radar on board R/V Mirai SOLA (IF 1.9) Pub Date : 2023-09-05 Masaki Katsumata, Biao Geng
An alternative method to estimate the differential reflectivity (ZDR) bias is proposed. The method collects data bins with “weak echo” by the liquid hydrometeor, which theoretically should be spherical (not oblate) to result in a ZDR of ∼0 dB, to calculate the averaged ZDR as the bias. The obtained results are comparable to those from traditional “birdbath” scans in hourly data to prove the validity
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Correcting GSMaP through histogram matching against satellite-borne radar-based precipitation SOLA (IF 1.9) Pub Date : 2023-08-29 Yuka Muto, Kaya Kanemaru, Shunji Kotsuki
Improving the accuracy of global precipitation estimates is practically important to predict hydrological disasters such as floods and droughts. Owing to the Global Precipitation Measurement mission and its constellation satellites, surface precipitation can be estimated globally based on microwave radiometers (MWRs). However, MWR-based precipitation is known to be biased, such as overestimation over
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The Role of Convection in Troposphere-Lower Stratosphere Interactions in Radiative-convective Equilibrium Simulations SOLA (IF 1.9) Pub Date : 2023-08-04 Tzung-Yu Tsai, Jin-De Huang, Chien-Ming Wu, Shih-Hao Su
This study investigates interactions between the lower stratosphere and troposphere in the idealized Radiative-Convective Equilibrium (RCE) simulation using the Vector Vorticity cloud-resolving Model (VVM). We conducted a long-term RCE simulation with an elongated domain size and high resolution for two years. This allows for a comprehensive analysis of the relationship between domain-averaged zonal
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Development and classification of Japanese-region-specific aerosol models based on 10-year sky radiometer observations SOLA (IF 1.9) Pub Date : 2023-08-04 Hiroyasu Kobayashi, Hitoshi Irie, Masahiro Momoi, Takeru Ohno, Hirokazu Yamamoto, Pradeep Khatri, Itaru Sano, Hiroshi Okumura, Hiroshi Kobayashi
To improve remote sensing techniques for global environmental research, aerosol models, indispensable inputs to radiative transfer calculations, should be region specific. Here, we focus on the Japanese region, which is situated downwind of the Asian continent, including China, characterized as one of the most significant sources of aerosols globally. By combining 10-year-long sky-radiometer-retrieved
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Variability of future increases in summertime extreme high temperatures on the Kanto Plain, Japan SOLA (IF 1.9) Pub Date : 2023-07-13 Rui Ito, Chieko Suzuki, Shiori Sugimoto
Large ensemble climate projections for Japan's Pacific side depict a greater increase in extreme high temperatures than in mean temperature, driven by changes in near-surface pressure arising from global warming. An exception to this pattern is the Kanto Plain, also on the Pacific side, for which a smaller increase is simulated. We investigated, using the large ensemble projections, the causes on this
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Applying the Sinkhorn Algorithm for Resampling of Local Particle Filter SOLA (IF 1.9) Pub Date : 2023-07-05 Ken Oishi, Shunji Kotsuki
The particle filter attracts interest from the data assimilation research community since it does not assume a Gaussian prior error distribution. Several local particle filters (LPFs) have been proposed to avoid weight collapse due to assimilation of observations in high dimensional systems. This study focuses on an LPF that uses the ensemble transform matrix as used in the local ensemble transform
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Quality evaluation of the column-averaged dry air mole fractions of carbon dioxide and methane observed by GOSAT and GOSAT-2 SOLA (IF 1.9) Pub Date : 2023-07-01 Yukio Yoshida, Yu Someya, Hirofumi Ohyama, Isamu Morino, Tsuneo Matsunaga, Nicholas M. Deutscher, David W. T. Griffith, Frank Hase, Laura T. Iraci, Rigel Kivi, Justus Notholt, David F. Pollard, Yao Té, Voltaire A. Velazco, Debra Wunch
Column-averaged dry air mole fractions of carbon dioxide and methane (XCO2 and XCH4) retrieved from SWIR (Short-Wavelength InfraRed) observations by GOSAT (Greenhouse Gases Observing SATellite) since 2009 and its successor GOSAT-2 since 2019 are available from NIES (National Institute for Environmental Studies) as SWIR L2 (Level 2) products. This paper shows the current status of the data quality of
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Intercomparison of Synthetic Inflow Turbulence Generation Methods for Large-Eddy Simulation Models in Thermally Driven Convective Boundary Layer Simulations SOLA (IF 1.9) Pub Date : 2023-06-22 Takuto Sato, Hiroyuki Kusaka
In this study, synthetic inflow turbulence generation methods developed in computational fluid dynamics (CFD) and meteorological fields were applied to thermally driven convective boundary layer (CBL) simulations. Methods developed in the CFD field include the Reynolds stress Cholesky decomposition and digital filter-based method (DF method), and the cell perturbation method (CPM) is a method developed
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Independent bias correction method for satellite observation data introduced to CO2 flux inversion SOLA (IF 1.9) Pub Date : 2023-06-15 Takashi Maki, Keiichi Kondo, Kentaro Ishijima, Tsuyoshi T. Sekiyama, Kazuhiro Tsuboi, Takashi Nakamura
Satellite observations are expected to play an important role in studying carbon fluxes. However, it is necessary to properly remove spatiotemporal bias from these observations. In this study, we estimated the spatiotemporal bias in satellite XCO2 data by making an inversion of in-situ observations. Compared to the GOSAT XCO2 concentrations derived from this analysis, the global average difference
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Sensitivity and Predictability of an Extreme Rainfall Event in Sulawesi, Indonesia SOLA (IF 1.9) Pub Date : 2023-06-13 James D. Doyle, Carolyn A. Reynolds, Maria Flatau, Beata Latos
The Makassar Peninsula in southwestern Sulawesi, Indonesia, experienced its largest flood in its recorded history in January 2019. Four-day accumulated rainfall exceeded 350 mm with devastating impacts on the community, including 53 perished and over 14 thousand evacuated. Previous studies find a convectively coupled Kelvin wave and convectively coupled equatorial Rossby wave associated with the Madden-Julian
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An equilibrium raindrop size distribution associated with a heavy-rain-producing convective system in Japan SOLA (IF 1.9) Pub Date : 2023-06-09 Takashi Unuma, Hiroshi Yamauchi, Akihito Umehara, Teruyuki Kato
We investigated the microphysical mechanisms for the enhancement of rainfall in a precipitating system that spawned heavy rainfall over the central part of the Kanto Plain in eastern Japan on 12 July 2022. Optical disdrometer observations confirmed the existence of an equilibrium state in the raindrop size distribution, especially when the precipitation intensity was high (e.g., 20 mm hr−1). As the
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Characteristics of the Environmental Conditions for the Occurrence of Recent Extreme Rainfall Events in Northern Kyushu, Japan SOLA (IF 1.9) Pub Date : 2023-06-05 Nanami Naka, Tetsuya Takemi
Using mesoscale gridded analysis data and radar/raingauge-analyzed precipitation products, this study investigated the environmental conditions for the occurrence of extremely heavy rain events that occurred in northern Kyushu during the warm season in recent years. In all cases, the environmental conditions were not particularly unstable but were almost saturated in the deep layer of the troposphere
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Response of Intensity and Structure of Typhoon Jebi (2018) before Landfall to 2-K and 4-K Warmed Future Climates in Dynamical Downscaling Experiments SOLA (IF 1.9) Pub Date : 2023-06-03 Keita Fujiwara, Tetsuya Takemi, Nobuhito Mori
To investigate the effects of global warming on Typhoon Jebi (2018), we performed high-resolution pseudo-global 2-K and 4-K warming simulations with initial time ensembles using a regional atmospheric model. The pseudo-global warming experiments demonstrated the further facilitation of Jebi's development with a higher rise in the temperature. The intensity over the ocean to the south of Japan increased
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Reevaluating the surface energy balance and soil thermal diffusion equations in the Noah multi-parameterization (Noah-MP) scheme SOLA (IF 1.9) Pub Date : 2023-05-30 Mikio Nakanishi
The Noah multi-parameterization (Noah-MP) scheme is one of several land surface schemes implemented in the Weather Research and Forecasting (WRF) model. Our simulations by the WRF model with the Noah-MP scheme show that surface air temperatures in the morning and evening tend to be higher and lower, respectively, than observed, and that the temperatures at an urban station with snow cover increase
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Internal Precipitation and Kinematic Structure of the South Pacific Convergence Zone SOLA (IF 1.9) Pub Date : 2023-05-24 Biao Geng
This study investigated the internal precipitation and kinematic structure of the South Pacific convergence zone (SPCZ) observed by the Doppler radar aboard the research vessel Mirai, which passed through the western tropical portion of the SPCZ on December 17-21, 2016. Convective precipitation developed in association with the low-level convergence induced by the monsoon and the upper-level divergence
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Simultaneous Observations of Atmosphere and Ocean Directly under Typhoons Using Autonomous Surface Vehicles SOLA (IF 1.9) Pub Date : 2023-05-22 Naoko Kosaka, Yusuke Umemiya, Naoto Endou, Tsuneko Kura, Hiroshi Matsubara, Masaki Hisada, Akinori Murata, Satoshi Mitarai
This paper presents experimental observations to improve typhoon prediction accuracy and to understand interactions between atmosphere and ocean directly under typhoons. Two unmanned surface vehicles (Wave Gliders (WGs)) equipped with interchangeable sensors were sailed toward the path of an approaching Category 5 typhoon (Hinnamnor), which began on 29 August 2022 and subsided on 6 September, reaching
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Tropical Cyclone Track Modified by a Front Located to the Northeast SOLA (IF 1.9) Pub Date : 2023-05-16 Soichiro Hirano, Kosuke Ito, Hiroyuki Yamada
In the western North Pacific, as a tropical cyclone (TC) translates northward and approaches the midlatitude jet region, a front is often observed to the northeast of the TC, especially in fall. Theoretically, a front accompanies positive vorticity in the lower troposphere because convergence of cross-frontal circulation generates positive vorticity. Horizontal winds accompanied by positive vorticity
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A projection of future JPCZs by WRF dynamical downscaling simulations based on MIROC6 ScenarioMIP ssp585 SOLA (IF 1.9) Pub Date : 2023-05-10 Tetsuya Kawano, Rina Yasukiyo, Ryuichi Kawamura, Takashi Mochizuki
Downscaling simulations of MIROC6 (the sixth version of Model for Interdisciplinary Research on Climate) data using the Weather Research and Forecasting (WRF) model were performed to investigate future changes in the Japan Sea polar airmass convergence zones (JPCZs) related to heavy snowfall events in the Sea of Japan–side region of central and northern Japan. WRF downscaling simulations showed a northward
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Monitoring of recent aridification in Türkiye using MODIS satellite data from 2000 to 2021 SOLA (IF 1.9) Pub Date : 2023-04-22 Reiji Kimura, Masao Moriyama, Levent Saylan
Simulations of future climate indicate that the Mediterranean countries will see increasing temperatures, and decreasing precipitation. In Türkiye, which has a semi-arid and dry sub-humid climate, the coupled effect of warming and drought is expected to lead to a general increase in aridity. We applied indices derived from satellite data to provide continuous monitoring for drought hazards and evaluated
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Water vapor in the upper troposphere above Syowa Station in the Antarctic: Its variations and causes SOLA (IF 1.9) Pub Date : 2023-04-15 Yoshihiro Tomikawa, Masashi Kohma, Masanori Takeda, Kaoru Sato
An intensive balloon-borne observation was performed at Syowa Station in the Antarctic (69.0°S, 39.6°E) in July 2016 using Cryogenic Frostpoint Hygrometers (CFH) and Electrochemical Concentration Cell (ECC) ozonesondes. High water vapor concentration was observed in the upper troposphere in two out of five observations. Trajectory analysis and atmospheric reanalysis data showed that moist air was transported
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Bimodal distribution of precipitation found in the multimodel climate prediction over central Japan in winter SOLA (IF 1.9) Pub Date : 2023-04-13 Naoki Sato, Takeshi Horinouchi, Yoshio Kawatani
Large-scale trends related to the precipitation in central Japan were investigated in the Coupled Model Intercomparison Project 5 dataset. In the Representative Concentration Pathways 4.5 projections, surface temperature over central Japan increases by 1 to 4 K during the 21st century in most models. Focusing on the trend of surface-air temperature and precipitation in central Japan, these models were
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Observed Concentric Eyewalls of Supertyphoon Hinnamnor (2022) SOLA (IF 1.9) Pub Date : 2023-03-31 Sachie Kanada, Akira Nishii
Ground-based radar observations of the concentric eyewalls (CEs) of supertyphoon Hinnamnor (2022) showed that CEs evolved as follows: (Stage 0) development of a distinct stationary band complex (SBC) downshear in moderate south-southeastward vertical wind shear (VWS), (Stage 1) maturity of the secondary eyewall (SE), (Stage 2) contraction of the SE, and (Stage 3) decay of the CE structures. From Stage
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Regional dependency of the cloud droplet growth process in combined analysis of Aqua MODIS and CloudSat CPR SOLA (IF 1.9) Pub Date : 2023-03-14 Yu Matsumoto, Minrui Wang, Yousuke Sato, Takashi Y. Nakajima
This paper shows the CFODD of the regional dependence of cloud growth processes in low-level clouds obtained by the combined use of the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite and the Cloud Profiling Radar (CPR) on the CloudSat satellite. This enabled the evaluation of the cloud growth process based on the cloud optical thickness (τ) and the effective radius
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Gross assessment of the dynamical impact of numerous power-generating sailing ships on the atmosphere and evaluation of the impact on tropical cyclones SOLA (IF 1.9) Pub Date : 2023-03-10 Takeshi Horinouchi, Taiga Mitsuyuki
The use of massive sailing ships has been proposed as a means of acquiring renewable energy. It has also been proposed that such ships can be used to reduce the intensity of tropical cyclones (TCs). Here we propose a basis for evaluating the dynamical impacts of numerous sailing ships on the atmosphere. The key parameter is the total sail area per unit horizontal area (referred to as β), which is proportional
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Impacts of an Urban Canopy Scheme and Surface Observation Data on a Heavy Rain Event through Data Assimilation SOLA (IF 1.9) Pub Date : 2023-03-10 Ken Sawada, Naoko Seino, Takuya Kawabata, Hiromu Seko
Considering urbanization effects on atmospheric states and subsequent precipitation is crucial to improve the accuracy of forecasting localized heavy rainfall around urban areas and to mitigate related disasters. For this purpose, it is effective to use a time development model that can accurately represent city-specific effects, such as urban heat island effect, in the assimilation process, and to
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Characteristics Analysis of the Senjo-Kousuitai Conditions in the Kyushu Region in Early July: The Case of the July 2020 Heavy Rainfall Event SOLA (IF 1.9) Pub Date : 2023-02-10 Masaki Satoh, Keisuke Hosotani
A sequence of heavy rainfall events due to quasi-stationary band-shaped precipitation systems, or “senjo-kousuitai“, was observed in the Kyushu region, Japan, from 3 to 8 July 2020. In this study, we investigate two of six indices that have previously been used to determine conditions favorable for senjo-kousuitai, i.e., water vapor flux at the height of 500 m and storm-relative environmental helicity
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Simulating the Impact of Bushfires in Australia on Local Air Quality and Aerosol Burden in the Southern Hemisphere SOLA (IF 1.9) Pub Date : 2023-02-07 Kai Cao, Xiao Tang, Lanning Wang, Xueshun Chen, Qizhong Wu, Lei Kong, Miaomiao Lu, Huangjian Wu, Zifa Wang
From the end of 2019 to the beginning of 2020, Australian bushfires caused by high temperatures and drought significantly impacted the local and global atmosphere. This work uses the global atmospheric chemistry transport model and observations to assess the enormous impact of bushfire emissions on PM2.5 in Australia. During December 2019, the significant increase in biomass-burning emissions led to
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The critical role of the upper-level synoptic disturbance on the China Henan “21.7” extreme precipitation event SOLA (IF 1.9) Pub Date : 2023-02-01 Yang Zhao, Seok-Woo Son, Seung-Yoon Back
On 18-20 July 2021, Henan Province in China experienced a historically rare extreme precipitation event, termed as the “21.7” event. Its synoptic environment was characterized by a large amount of moisture supply by binary typhoons located over the ocean and a potential vorticity intrusion in the upper level. The present study examines the importance of the latter by conducting WRF model experiments
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Biases in Shortwave Three-Dimensional Radiative Transfer Calculations for High-Resolution Numerical Models SOLA (IF 1.9) Pub Date : 2023-01-30 Ken Hirata, Miho Sekiguchi, Yousuke Sato, Masaru Inatsu
This study investigated biases of diffuse radiation in a look-up table approach, which pre-computed the sequential ray tracing to avoid heavy computation in full three-dimensional radiative transfer calculation. We introduced corrections that enhanced directionality of radiative propagation in the solar angle and horizontal direction. By comparing irradiance calculations with and without the corrections
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Decreasing quiescence of tropical cyclones in the Western North Pacific SOLA (IF 1.9) Pub Date : 2023-01-20 Ger Anne W. Duran, Joseph Q. Basconcillo
Due to less tropical cyclone (TC) occurrences, the climatology of the quiescent TC season (i.e., March-April-May, MAM) in the Western North Pacific (WNP) is less understood when compared to the more active season (i.e., June-November). Here we show observational evidence of significantly decreasing TC quiescence during MAM that can be attributed to more Central Pacific El Niño events from 2002 to 2022