Papers in Meteorology and Geophysics最新文献

{"title":"Estimation of JMA-Magnitude for Slow Tsunami Earthquakes","authors":"Takahito Nishimiya, A. Katsumata","doi":"10.2467/mripapers.70.1","DOIUrl":"https://doi.org/10.2467/mripapers.70.1","url":null,"abstract":"When an earthquake occurs and a tsunami threatens, rapid issuance of the first tsunami warning is important for timely evacuation of coastal residents. For tsunami early warning, estimates of an earthquake’s hypocenter and magnitude are usually used. In Japan, the Japan Meteorological Agency (JMA) magnitude MJ, which is based on the observed displacement amplitude, is used to estimate the first tsunami warning. Slow tsunami earthquakes, such as the 1896 Meiji Sanriku earthquake, generate high tsunami waves but relatively small seismic waves. Thus, the use of MJ can cause underestimation of the size of such earthquakes and, therefore, lead to underestimation of the tsunami wave height. Quantitative understanding of the underestimation of slow tsunami earthquake magnitudes is needed, but local seismic records of slow tsunami earthquakes are scarce. In this study, we conducted spectrum analyses of teleseismic waves and used previously reported moment rate functions to construct synthetic local seismic wave records for slow tsunami earthquakes. First, we used data of earthquakes that occurred off the Japanese coast to confirm the validity of this method of constructing synthetic records. Then, we assumed tsunami earthquakes occurring off Miyagi Prefecture or the Sanriku Coast of Japan with the same moment rate functions as five major historical slow tsunami earthquakes, and compared our estimated magnitudes for these assumed earthquakes with the moment magnitudes (MW) of the five slow tsunami earthquakes. We found that MJ underestimated the size of the assumed earthquakes by 1 or more magnitude units when compared with MW. We also evaluated M100, a scale introduced after the 2011 Tohoku earthquake to supplement MJ and avoid underestimation of magnitude 9 class earthquakes. We found that M100 underestimated magnitudes by 0.5 or more magnitude units. Additionally, we suggest that amplitude distributions obtained from long-period seismic monitors, which were introduced to prevent underestimation of the magnitude of huge earthquakes, may be effectively used to estimate magnitudes of slow tsunami earthquakes. Corresponding author: Takahito Nishimiya Department of Seismology and Tsunami Research, Meteorological Research Institute 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan. E-mail: tnishimi@mri-jma.go.jp © 2022 by the Japan Meteorological Agency / Meteorological Research Institute Nishimiya, T. and A. Katsumata Vol. 70 2 ラスの平成 23 年東北地方太平洋沖地震において過小 評価となったが M 8 程度までの規模の地震に対しては モーメントマグニチュード(MW)にほぼ等しい適正な M が得られる(Hirose et al. 2011)。平成 23 年東北地方 太平洋沖地震における過小評価後は、巨大地震対策と して MJ の過小評価を補うための、地震波の最大振幅 を使った他の迅速な規模推定手法も用いられるように なっている(気象庁 2013)。 一方、地震波の最大振幅から推定する M(以後単に M と記した場合は、最大振幅から求めるマグニチュー ドを指す)に対して不均衡に大きな津波をもたらす津 波地震が知られ、多くの犠牲者が生じた明治三陸津波 地震もその 1 つとされる(Kanamori 1972)。Kanamori (1972)は、明治三陸津波地震の震源断層の破壊が、断 層の大きさの割にゆっくりであることを指摘した。ま た Polet and Kanamori(2000)は、1992 年から 1996 年 までに沈み込み帯で発生した MW 7.0 以上の浅い地震の 震源スペクトルを推定した結果、大きな津波を伴った 地震の中に震源スペクトルの 1 ~20 秒で見ると振幅が 通常の地震に比","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of an Objective Detection Method of Long-Term Slow Slip Events using GNSS Data: Detection of Short-Term Slow Slip Events and Estimation of Moment Magnitude of Long-Term Slow Slip Events","authors":"A. Kobayashi","doi":"10.2467/MRIPAPERS.69.1","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.69.1","url":null,"abstract":"Long-term and short-term slow slip events (SSEs) have occurred repeatedly in the Nankai Trough subduction zone, Japan. The SSEs may incrementally stress the adjacent parts of the locked megathrust zone. When SSEs occur, it is important to determine whether they are similar to previous repeated events, in order to judge whether the probability of occurrence of a large Nankai Trough earthquake is relatively high. In this study, we objectively detected short-term SSEs in the Nankai Trough subduction zone by correlating the GNSS daily and 6-hour coordinates with a ramp function with a one-week slope, excluding common noise and long-term trends. The spatiotemporal distribution of short-term SSEs detected was in good agreement with the occurrence of deep low-frequency earthquakes. In addition, assuming slip on a rectangular fault on a plate boundary, we estimated the moment magnitude of long-term SSEs from displacement data for two years and obtained results that were close to those of previous studies. Corresponding author: Akio Kobayashi Department of Seismology and Tsunami Research, Meteorological Research Institute 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan. E-mail: akobayas@mri-jma.go.jp © 2021 by the Japan Meteorological Agency / Meteorological Research Institute A. Kobayashi Vol. 69 2 規模によっては検出できることが示された(Nishimura et al. 2013)。同じ現象を複数の観測項目で監視すること で観測結果の信頼度は向上すること、ひずみ計の観 測点は GNSS と比較して数が少なく観測点分布が一 様ではないことから、ひずみ計や傾斜計に加えて、 GNSS による検出も併用することが重要である。また、 Kobayashi(2017)による手法は長期的 SSE に伴う変位 の確からしさを示すもので、SSE の規模を推定するも のではない。長期的 SSE および短期的 SSE について、 GNSS データを用いて即時的に位置や規模を推定する ことを目標に、ここでは以下の手法を開発・検証した。 2 章では、Kobayashi(2017)の手法を応用し、注目 する現象の継続時間を短くすることにより、GNSS 日 値による短期的 SSE の客観的な検出を試みる。また、 東海地域のみより時間発展の短い現象の検出のために、 GNSS の 6 時間座標値(6 時間値)が 3 時間ごとに求め られている(小林 2007)。3 章では、この GNSS6 時間 値を用いた場合の短期的 SSE の検出について検討する。 4 章では、客観検出手法を応用した長期的 SSE の規模","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deepening and Evolution of a Low over the Sea of Japan in Late August in 2016: Interaction of Midlatitude Flows and Typhoon Lionrock (1610)","authors":"N. Kitabatake, Hiroshige Tsuguti","doi":"10.2467/mripapers.68.1","DOIUrl":"https://doi.org/10.2467/mripapers.68.1","url":null,"abstract":"This study examined a midlatitude low pressure system that deepened to 974 hPa over the Sea of Japan on 31 August 2016 using the Japanese 55-year reanalysis (JRA-55) dataset. The low appears to have developed by absorbing Typhoon Lionrock (2016). This unusual development of the low occurred in a relatively weak baroclinic environment in association with high potential vorticity air that moved southeastward and downward along a slantwise isentropic surface in the upper troposphere. Middle and lower tropospheric warming also contributed to the deepening of the surface low. In the last stage of its development, the upper-tropospheric trough became coupled with Typhoon Lionrock. Lionrock also contributed to the deepening of the low at an earlier stage by inducing moist air to flow in the lower troposphere between Lionrock and a high pressure system located to its north. The consequent latent heat release over the Sea of Japan led to intensification of the upper-tropospheric ridge and increased vorticity advection. These are also considered to have contributed to the deepening of the low.","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tropical cyclone forecasts for the Western North Pacific with high-resolution atmosphere and coupled atmosphere-ocean models","authors":"Kosuke Ito, M. Sawada, M. Yamaguchi","doi":"10.2467/MRIPAPERS.67.15","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.67.15","url":null,"abstract":"This work quantified the skills of high-resolution regional nonhydrostatic models in forecasting tropical cyclones (TCs) in the Western North Pacific. The selected cases were almost all TCs during 2012–2014 with an initial time of 1200 UTC. The Japan Meteorological Agency (JMA)-nonhydrostatic model with a horizontal grid spacing of 5 km (NHM5km_atm) and its atmosphere-ocean coupled version (NHM5km_cpl) were used to conduct three-day forecasts. The JMA-global spectral model (GSM) outputs interpolated to a horizontal grid spacing of 0.5 degree were used for initial and lateral boundary conditions of the NHM5km_atm and NHM5km_cpl. The skills and GSM forecast skill were validated with respect to the Regional Specialized Meteorological Center Tokyo best track dataset. Results showed that use of the NHM5km_atm and NHM5km_cpl generally improved track forecasts at forecast times of 24–60 h. Track forecasts improved by as much as 20% for TCs with strong vertical shears of horizontal winds. However, a two-tailed test for the mean value revealed that the improvements were not statistically significant above the 90% confidence level. Use of the NHM5km_atm and NHM5km_cpl significantly improved TC intensity forecasts of 2–3 days by more than 20% with respect to the GSM, but strong TC intensities were not well predicted by short-term forecasts because of initialization deficiencies. Although the NHM5km_cpl tended to seriously underestimate TC intensities, it tended to produce the greatest increase in the correlation coefficient between observed and predicted intensity changes. This study also showed that the method used to determine the TC center position affects the track forecast error by up to a few percent and that the maximum wind speed forecast error depends on the best track dataset selected as a reference.","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"67 1","pages":"15-34"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2467/MRIPAPERS.67.15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a new methane calibration system at JMA for WCC Round Robin experiments","authors":"H. Matsueda, K. Tsuboi, Shinya Takatsuji, Teruo Kawasaki, Masamichi Nakamura, Kazuyuki Saito, A. Takizawa, Kohshiro Dehara, Shuichi Hosokawa","doi":"10.2467/MRIPAPERS.67.57","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.67.57","url":null,"abstract":"A new calibration system of methane (CH4) standard gases by using a wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) analyzer was developed at the Japan Meteorological Agency (JMA) in collaboration with the Meteorological Research Institute. We used two sets of CH4 primary standard gases with mole fractions assigned based on the World Meteorological Organization (WMO) CH4 mole fraction scale maintained by the National Oceanic and Atmospheric Administration to test the performance of the new WS-CRDS calibration system. Our results showed high repeatability (0.06 nmol mol) and reproducibility (0.07 nmol mol) of measurements and good linearity against the WMO CH4 mole fraction scale. The CH4 calibration results for the new system agree well with those of the previous JMA calibration system, which employed a gas chromatograph with a flame ionization detector (GC/FID). These tests indicate that the new WS-CRDS CH4 calibration system at JMA will provide results that are consistent with those of the previous GC/FID system but with precision that is one order of magnitude higher. We also evaluated the stability and consistency of the JMA calibrations over the past 10 years by examining data from the World Calibration Centre (WCC) Round Robin comparison experiments in Asia and the regions in the southwest Pacific. The results of our study clearly demonstrate that the new calibration system will provide more precise CH4 measurements and improved traceability to the WMO scale of atmospheric CH4 measurements for the JMA/WCC comparisons. Corresponding address: Oceanography and Geochemistry Research Department, Meteorological Research Institute 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan. E-mail: hmatsued@mri-jma.go.jp © 2018 by the Japan Meteorological Agency / Meteorological Research Institute Matsueda, H. et al. Vol. 67 58 much as ~10 nmol mol; this value is considerably larger than the analytical precisions of ~1−2 nmol mol at individual laboratories (e.g., Matsueda et al., 2004; Dlugokencky et al., 2005; Tsuboi et al., 2017). Careful and regular calibration of measuring devices and comparison of calibration scales among laboratories are fundamental requirements for analyses of global observation data. The World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) programme coordinates systematic observations and analyses of atmospheric CH4 and other trace gas species (http://www.wmo.int/gaw). Measurement data are posted by WMO/GAW participating laboratories and archived and distributed by the World Data Centre for Greenhouse Gases (WDCGG) at the Japan Meteorological Agency (JMA). The WMO/GAW programme strives to achieve compatibility among participating laboratories of ±2 nmol mol for measurements of CH4 in well-mixed background air (WMO, 2016); this precision is deemed sufficient for detection of global trends related to climate change. The WMO/ GAW requires datasets to be traceable to a common reference. The National Oceanic and ","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"67 1","pages":"57-67"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2467/MRIPAPERS.67.57","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69026102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An improved equation for estimating diurnal atmospheric radiation near the surface in Japan","authors":"T. Fujieda","doi":"10.2467/MRIPAPERS.67.1","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.67.1","url":null,"abstract":"It is important to evaluate precisely whether observational data that include screen-level air temperatures could be affected by the environment around meteorological surface observation stations. It is well known that atmospheric radiation (downward long-wave radiation) from the atmosphere and clouds affects the temperature of the ground as well as observational air temperature data, but there are few stations that observe atmospheric radiation. Therefore, various formulas have been proposed and developed to estimate the atmospheric radiation under clear sky conditions that use air temperature and water vapor pressure; these are used in earth surface models to estimate average hourly thermal energy budgets in the planetary boundary layer. It is necessary to verify whether the formulas are applicable for recent data in Japan, because these formulas were developed with data collected at local observation stations during specific periods. In this study, the accuracy of the familiar formulas used for estimation of diurnal atmospheric radiation under clear sky conditions was evaluated. Results from the formulas were compared with observational data from five stations, namely Sapporo, Tateno (Tsukuba), Fukuoka, Ishigaki Island, and Marcus Island, at which renovated solar and infrared radiation observations commenced on 31 March 2010. It was found that there were noticeable differences between observations and calculations as well as their seasonal variations. Therefore, the coefficients of Brutsaert (1975), which are comparatively theoretical, were adjusted to fit the regional meteorological conditions. The new Brutsaert-type formulas caused the differences","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"60 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2467/MRIPAPERS.67.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of ozone in the middle troposphere over Japan from 6-year observation at the summit of Mount Fuji (3776m)","authors":"Y. Tsutsumi","doi":"10.2467/MRIPAPERS.67.45","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.67.45","url":null,"abstract":"The continuous measurement of tropospheric ozone was made at the summit of Mt. Fuji (3776 m a.s.l.) for 6 years (1992-1998). The observations suggest some characteristic features of ozone in the middle troposphere over Japan. The annual variation at the summit of Mt. Fuji shows a bimodal seasonal trend; May and October maxima and August and December minima. The summer minimum, which causes the bimodal seasonal trend, is resulted from the domination of the ozone-depleted maritime air at the summit. In June, however, the enhanced ozone (>60 ppbv) is occasionally observed at the summit in the air with low water-vapor mixing ratio and high potential vorticity (PV), suggesting that it has origins in the stratosphere or the upper troposphere. The small variance of ozone during the winter is suggested by the winter photochemistry on ozone and strong zonal winds. The infrequent ozone intrusions from the stratosphere are also thought to contribute to the small variance of ozone during the winter. The synchronization of the annual course of daily-mean ozone with the clear-sky solar radiation at the summit from late autumn to early spring and the coincident of the both minima in late December suggest that the solar radiation controls ozone observed at the summit during this period of time. In the spring, the daily-mean ozone simultaneously increases with the daily solar radiation besides the ozone concentrations do not correlate with PV, suggesting that the spring ozone maximum at the summit of Mt. Fuji is mainly resulted from photochemical ozone production. However, the possibility of partial contribution of indirect stratospheric ozone intrusions or aged stratospheric ozone to the spring ozone maximum cannot be ruled out. The 6-year observation of ozone at the summit shows the increase trend of 0.49 ppbv year-1, but it is not significant at 95% significance level. 4.088","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"67 1","pages":"45-56"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69026040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the choice of precipitation data to utilize for correction of volumetric strainmeter signals","authors":"K. Kimura","doi":"10.2467/MRIPAPERS.67.35","DOIUrl":"https://doi.org/10.2467/MRIPAPERS.67.35","url":null,"abstract":"","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"67 1","pages":"35-44"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69025984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Ozone Amounts Measured at Delhi (28I/2°N), Srinagar (34°N) and Tateno (36°N) in 1957~58","authors":"R., N. Kulkarni, P. Angreji, K. Ramanathan","doi":"10.2467/mripapers1950.10.2_85","DOIUrl":"https://doi.org/10.2467/mripapers1950.10.2_85","url":null,"abstract":"A new ozone station was established in Kashmir (34°N) in 1955 in a region where double tropopauses are frequent in winter and spring. In this paper, a comparison is made of the ozone amounts measured at Delhi (281/2°N) and Srinagar (34°N) in India and at Tateno (36°N) in Japan in 1957-58. The ozone amounts at Tateno are much larger than at Srinagar although the latitude of Tateno is only 2° greater than that of Srinagar. It is recalled that at Zi-Ka-Wei and Cairo, which are at lower latitndes than Srinagar, significantly higher ozone values had been recorded in winter. It is thus evident that there is a large geographical influence on the total ozone amount measured at a place. Apparently, the Himalayas and the Indian summer monsoon exert a strong depressing influence on the ozone amount south of the Himalayas and incursions of the cold Siberian anti-cyclone tend to bring with it larger amounts of ozone over China and Japan. The seasonal variation of ozone over N. India was of an unusual character in 1957. A summary of the results of the ozone measurements made in India prior to 1954 was given by RAMANATHAN (1954) at the Rome Meeting of the International Association of Meteorology. The day-to-day variations of ozone are small during most of the year and surface weather conditions do not seem to affect them. In December to April, however, there are significant variations of ozone over Mt. Abu and New Delhi, this being the period when active western disturbances move across N. India. The transition from the autumn minimum of ozone to the comparatively high values in winter and spring takes place in a succession of surges, the first surge approximately coinciding with the onset of strong upper westerlies over N. India. Some pronounced surges are associated with the passage of deep troughs of low pressure at 6 and 9 km. The rise of ozone during a surge takes place when northwesterly winds are replacing the southwesterlies, but once the northwesterlies get settled, the ozone amount begins to fall. However, ozone fluctuations could not be * Paper presented at the International Ozone Symposium at Oxford in July 1959. 86R. N. Kulkarni, P. D. Angreji and K. R. Ramanathan Vol. X No. 2 explained in terms of shifts in wind direction at pilot balloon levels. Middle latitude variations of ozone associated with waves in the upper atmosphere are observable even at latitudes down to 20°N in winter and spring. The association of ozone changes with western disturbances was confirmed from later observations made at Delhi, Mt. Abu and Quetta. Since 1955, observations on the total amount of ozone and its vertical distribution have been made at Srinagar (34°N) at a latitude where double tropopauses are frequent. An ozone observing station was established at Srinagar in May 1955 by transferring a DOBSON'S spectrophotometer there. The optical wedges of the spectrophotometer were recalibrated and the constants determined. Frequent checks of calibration were made in the su","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2467/mripapers1950.10.2_85","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69026560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Some New Phenomena Observed in the 1970-1971 Eruption at Volcano Komagatake","authors":"T. Kizawa","doi":"10.2467/mripapers1950.23.2_136","DOIUrl":"https://doi.org/10.2467/mripapers1950.23.2_136","url":null,"abstract":"The eruptive activities of Komagatake, Akita Prefecture, which were recorded during the period from September 1970 to February 1971, are especially interesting on account of some unusual phenomena involved in lava flows and explosions. The writer expressed the characteristics of the volcano's mechanism of explosion in terms of S/M, that is, the ratio of two phase amplitudes of sound and earthquake in a seismogram of explosion (Fig. 6). Referring to the theoretical values of tide generating forces of Komagatake, the writer studied the nature of this activity and explained the depth of the source of explosion and its changes. The mechanism of the underground activities of Komagatake applies also to the Matsushiro earthquake swarm and activities of other volcanoes. During the eruptive activities, the \"smoke-ring\" was observed for the first time in Japan. Fortunately, the writer was able to observe the whole process of its formation from the crater, by means of an 8 mm cinecamera and the tapecorder. Then he carried out spectrum analysis and examined the relationship between the fluctuations of explosive energy and the seismic waves, so as to elucidate the cause of this unique phenomenon which is seldom recorded in the history of volcanoes of the world. At 14 : 16 in Oct. 24, 1970, a pillar-like white smoke emerged out of the crater with a detonation (Fig. 2-a-1). It grew with the top part gradually shaping into a horizontal ring as it became taller (Fig. 2-a-2). After 12 seconds, at a height of 50meters, the ring went up alone leaving the white pillar of smoke below. The ring was about 7 meters in diameter. The air current was seen to move relatively upwards inside the ring and downwards outside it. The ring travelled up for about 20 minutes until it disappeared in the cloud (AC) about 5, 000 meters high. The detonating sound of the explosion recorded on magnetic tape was analysed by band pass filters, the results being shown in Fig. 3-a, 3-b. There is little difference in strength between the detonation accompanied by \"smoke-ring\" and that without it. Marked difference, however, is seen in the type of spectrum of the detonation between that with \"smoke-ring\" (Fig. 4, top) and those without it. (Fig. 4, middle and bottom). Sound energy is more concentrated in the lower band of frequency in the former case than in the latter.","PeriodicalId":39821,"journal":{"name":"Papers in Meteorology and Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69031080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}