This study investigated the atmospheric and oceanic contributions to the genesis of Typhoon Faxai in 2019. Our statistical analysis using the tropical cyclone genesis score (TGS) attributed the ...tropical disturbance that developed into Faxai (Pre-Faxai) to easterly waves (EWs). The EW score evaluated by a grid version of the TGS (Grid-EW) averaged around the occurrence of Pre-Faxai was approximately twice as large as the climatological mean, and it was the second largest value in the past 38 years. The Pre-Faxai area with high Grid-EW scores could be traced back to the eastern North Pacific (ENP) around August 25, 2019. The lower-troposphere environment characterized by high Grid-EW scores was favorable for vortex formation because it provided a containment area for moisture entrained by the developing circulation or lofted by the deep convection therein. The Pre-Faxai area with high Grid-EW scores moved westward due to the background easterly flow over the ENP and then entered the western North Pacific (WNP). The Typhoon Intensity Forecast Scheme (TIFS) showed that the important environments for its genesis were ocean conditions and the vertical wind shear. The oceanic conditions contributed to the development of Pre-Faxai as it traveled over the WNP. The enhancement of vertical wind shear and subsequent suppression of the development of Pre-Faxai were caused by the lower-troposphere easterly winds associated with high EW scores. They were also caused by upper-troposphere westerly winds associated with an upper cold low northwest of Pre-Faxai. When the vertical shear decreased with weakening of the upper cold low, Pre-Faxai reached tropical storm intensity on September 4. Therefore, TGS and TIFS detected Pre-Faxai 10 days before the typhoon arose, which indicates that monitoring environmental factors such as EW and vertical wind shear are important for disaster prevention.
The Japan Meteorological Agency (JMA) started the second Japanese global atmospheric reanalysis project named the Japanese 55-year Reanalysis (JRA-55). It covers 55 years, extending back to 1958, ...when the global radiosonde observing system was established. Many of the deficiencies found in the first Japanese reanalysis, the Japanese 25-year Reanalysis (JRA-25), have been improved. It aims at providing a comprehensive atmospheric dataset that is suitable for studies of climate change or multi-decadal variability, by producing a more time-consistent dataset for a longer period than JRA-25. Production of JRA-55 started in 2010, and computations for more than 16 years have been completed as of August 2011. The entire JRA-55 production will be completed in early 2013 and thereafter JRA-55 will be continued as a new JCDAS on real time basis. This paper is a brief report to introduce the JRA-55 reanalysis project. The data assimilation and prediction (DA) system used in JRA-55 is introduced and compared to that used in JRA-25. Early results of JRA-55 are presented and discussed, showing general improvements.
This study investigated the characteristics and environmental conditions of tropical cyclones (TCs) over the western North Pacific from 2009 to 2017 that dissipated before reaching tropical storm ...strength (TDs) under unfavorable environmental conditions; we compared TDs with TCs that reached tropical storm strength (TSs) in terms of modulations of relevant large-scale flow patterns. The flow patterns were categorized based on five factors: shear line, confluence region, monsoon gyre, easterly waves, and Rossby wave energy dispersion from a preexisting cyclone. Among 476 cases, 263 TDs were detected using best-track data and early stage Dvorak analysis. The TCs in the environments associated with the confluence region or Rossby wave energy dispersion (easterly waves) tended to reach tropical storm strength (remain weak) compared with the other factors. The average locations of TDs at the time of cyclogenesis in the confluence region, monsoon gyre, and easterly waves (Rossby wave energy dispersion) in the summer and autumn were farther to the west (east and north) than those of TSs that exhibited the same factors. The environments around TDs were less favorable for development than those around TSs, as there were significant differences in atmospheric (oceanic) environmental parameters between TDs and TSs in the factors of confluence region, easterly waves, and Rossby wave energy dispersion (shear line, monsoon gyre, and Rossby wave energy dispersion). The environmental conditions for reaching tropical storm strength over their developing stage, using five factors, can be summarized as follows: higher tropical cyclone heat potential in the shear line and monsoon gyre, weak vertical shear in the confluence region, wet conditions in the easterly waves, and higher sea surface temperatures and an intense preexisting cyclone in Rossby wave energy dispersion from a preexisting cyclone.
The withdrawal of Baiu, the end of early summer rainy period over Japan, is marked by a stepwise northward migration of the westerly jet in the upper troposphere. The Coupled Model Intercomparison ...Project Phase3 (CMIP3) dataset was utilized to investigate possible changes in the seasonal development under a warmer climate. To obtain realistic model simulations, we evaluated model performance by comparing simulated and observed westerly jets for the present-day climate, selecting the top five models. Future climate projections using these models show that the westerly jet will be strengthened to the south of the jet axis, and the amount of precipitation in late July will be increased over the main land of Japan. These findings indicate that, by the end of the 21st century, withdrawal of the Baiu season will be delayed. The CMIP3 models also allowed changes in larger-scale atmospheric circulation to be predicted. Most of the CMIP3 models project that the Asian jet will be intensified on its equatorward side. Decreased upper tropospheric divergence in the western North Pacific and simultaneous shrinking of the Tibetan high suggest that the simulated change in the westerly jet is closely connected to the weakening of monsoonal circulation in Asia.
In preparation for the Fourth International Workshop on Tropical Cyclone Landfall Processes (IWTCLP-IV), a summary of recent research studies and the forecasting challenges of tropical cyclone (TC) ...rainfall has been prepared. The extreme rainfall accumulations in Hurricane Harvey (2017) near Houston, Texas and Typhoon Damrey (2017) in southern Vietnam are examples of the TC rainfall forecasting challenges. Some progress is being made in understanding the internal rainfall dynamics via case studies. Environmental effects such as vertical wind shear and terrain-induced rainfall have been studied, as well as the rainfall relationships with TC intensity and structure. Numerical model predictions of TC-related rainfall have been improved via data assimilation, microphysics representation, improved resolution, and ensemble quantitative precipitation forecast techniques. Some attempts have been made to improve the verification techniques as well. A basic forecast challenge for TC-related rainfall is monitoring the existing rainfall distribution via satellite or coastal radars, or from over-land rain gauges. Forecasters also need assistance in understanding how seemingly similar landfall locations relative to the TC experience different rainfall distributions. In addition, forecasters must cope with anomalous TC activity and landfall distributions in response to various environmental effects. Keywords: tropical cyclone, landfall, rainfall, nowcast, forecast verification
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Future changes in winter stationary waves are investigated using Coupled Model Intercomparison Project Phase 5 (CMIP5) models and a linear baroclinic model (LBM). The CMIP5 models showed a wave-like ...pattern of stationary waves from East Asia to the North Pacific and a weakening of horizontal divergence over the Maritime Continent. To investigate dynamical relationships among these changes, we performed LBM experiments using the zonal mean basic state and zonally asymmetric thermal forcing. The differences between the future and present experiments were similar to the changes projected by the CMIP5 models, although positions and amplitudes differed slightly. In addition, two of the LBM experiments showed that the change in the basic state explained most of the changes in the stationary wave, whereas the change in thermal forcing accounted for the eastward shift of the stationary wave. The storm track experiments conducted with the LBM to investigate the role of transient eddy feedback on stationary wave changes suggested that the feedback shifts the thermally forced stationary waves northeastward. This shift may explain the difference between the LBM experiments and the CMIP5 future projection.
The winter response of the Asian jet stream to global warming is investigated using the Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model dataset under the RCP4.5 scenario. We first ...evaluate model performances in reproducing the current climatology in the upper troposphere and select the best 27 models. A multi-model ensemble projection by the selected models indicates that the jet stream over the Indochina peninsula and the South China Sea is intensified on its equatorial side in the late 21st century, while the jet stream shifts poleward over the Eurasian continent and the North Pacific. The strengthening of the jet stream on the south side is associated with cyclonic (anticyclonic) circulation anomalies in the upper (lower) troposphere over the southern part of China and decreased upper tropospheric divergence over the Maritime Continent. The strength of the upper tropospheric divergence and the amplitude of the anticylonic eddy streamfunction are strongly correlated. These findings suggest that future changes in the jet stream are related to the weakening of a Matsuno-Gill response to tropical heating.
This study investigated the atmospheric and oceanic contributions to the genesis of Typhoon Faxai in 2019. Our statistical analysis using the tropical cyclone genesis score (TGS) attributed the ...tropical disturbance that developed into Faxai (Pre-Faxai) to easterly waves (EWs). The EW score evaluated by a grid version of the TGS (Grid-EW) averaged around the occurrence of Pre-Faxai was approximately twice as large as the climatological mean; it was the second largest value in the past 38 years. The Pre-Faxai area with high Grid-EW scores could be traced back to the eastern North Pacific (ENP) around August 25, 2019. The lower-troposphere environment characterized by high Grid-EW scores was favorable for vortex formation because it provided a containment area for moisture entrained by the developing circulation or lofted by the deep convection therein. The Pre-Faxai area with high Grid-EW scores moved westward because of the background easterly flow over the ENP, then entered the western North Pacific (WNP). The Typhoon Intensity Forecast Scheme (TIFS) showed that the important environments for its genesis were ocean conditions and the vertical wind shear. The oceanic conditions contributed to the development of Pre-Faxai as it traveled over the WNP. The enhancement of vertical wind shear and subsequent suppression of the development of Pre-Faxai were caused by the lower-troposphere easterly winds associated with high EW scores; they were also caused by upper-troposphere westerly winds associated with an upper cold low northwest of Pre-Faxai. When the vertical shear decreased with weakening of the upper cold low, Pre-Faxai reached tropical storm intensity on September 4. Therefore, TGS and TIFS detected Pre-Faxai 10 days before the typhoon arose, an indication that monitoring environmental factors such as EW and vertical wind shear are important for disaster prevention.
Five Cases of Torsion of the Gallbladder Oikawa, Yoshinori; Bandou, Michiya; Murata, Yuujirou ...
Nihon Fukubu Kyukyu Igakkai Zasshi (Journal of Abdominal Emergency Medicine),
2012/09/30, Volume:
32, Issue:
6
Journal Article
Open access
Between 2005 and 2010, we experienced 5 cases of torsion of the gallbladder, and examined useful findings for their preoperative diagnosis. We were able to diagnose 2 cases in 5 preoperatively, in ...which direct findings showing torsion of the gallbladder, such as the lack of contrast in the gallbladder wall on contrast-enhanced CT, the tapering and twisted cystic duct with coronal section image of contrast-enhanced CT, and disappearance of the bloodstream signal in the gallbladder wall on color Doppler sonography, were useful for the preoperative diagnosis. In addition, the following 7 factors were noted in all of 5 patients, including elderly female, lean figure, kyphosis, right hypochondrial pain in the physical examination, significant swelling of the gallbladder, floating gallbladder, and a high density area in the gallbladder wall suggesting hemorrhagic necrosis with an attenuation value ranging from 35 to 65 Hounsfield units on plain CT. It was thought that these were indirect findings seen with an increased frequency in torsion of the gallbladder. Our data suggested that, if these indirect findings were seen, they might lead to a preoperative diagnosis of torsion of the gallbladder when taken in combination with coronal section imaging on contrast-enhanced CT and color Doppler sonography.
A UHF-band RFID system handling many RF tags has some advantages over a bar code system such as simultaneous multi-reading and long read range. Especially, it has been strongly desired by the ...logistics and the retail industries for efficiency of operation. Recently, user-friendly RFID systems are being studied. We focused on a gate system using RFID technologies. If the tag moving direction can be recognized at the RFID gate system, it will be very useful for the efficiency of inventory management and the checking of pilferage or shoplifting. In this paper, new methods of tag moving direction detection using the difference of passing time of two antennas without expensive external sensors is proposed and evaluated.
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