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.
{"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}
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.
这项工作量化了高分辨率区域非流体静力模式在预测北太平洋西部热带气旋(tc)方面的技能。所选病例几乎全部为2012-2014年期间的tc，初始时间为UTC时间1200。利用日本气象厅(JMA)水平网格间距为5km的非流体静力模式(NHM5km_atm)及其大气-海洋耦合模式(NHM5km_cpl)进行了为期3天的预报。利用插值到0.5度水平网格间距的JMA-global spectral model (GSM)输出对NHM5km_atm和NHM5km_cpl的初始边界条件和侧向边界条件进行了研究。在区域专业气象中心东京最佳航迹数据集上验证了该技能和GSM预报技能。结果表明，NHM5km_atm和NHM5km_cpl在24 ~ 60 h的预报时间内总体上改善了路径预报，对于水平风强垂直切变的tc，路径预报提高了20%。然而，对平均值的双尾检验显示，在90%的置信水平之上，改善在统计学上并不显著。NHM5km_atm和NHM5km_cpl对2 ~ 3 d TC强度的预报较GSM提高了20%以上，但由于初始化不足，短期预报对强TC强度的预报效果较差。NHM5km_cpl虽然严重低估了TC强度，但其对TC强度变化的相关系数增加幅度最大。研究还表明，确定TC中心位置的方法对路径预报误差的影响可达几个百分点，最大风速预报误差取决于所选择的最佳路径数据集作为参考。
{"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}
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
{"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}
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
{"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}
Pub Date : 2012-01-01DOI: 10.2467/mripapers1950.10.2_85
R., N. Kulkarni, P. Angreji, K. Ramanathan
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
1955年在冬季和春季双对流层频繁出现的克什米尔(34°N)地区建立了一个新的臭氧站。本文比较了1957- 1958年印度德里(281/2°N)和斯利那加(34°N)和日本馆野(36°N)的臭氧量。Tateno的臭氧量比斯利那加大得多，尽管它的纬度只比斯利那加大2°。回顾，在比斯利那加纬度低的梓嘉卫和开罗，冬季记录到的臭氧值明显较高。由此可见，一个地方所测得的臭氧总量受地理因素的影响很大。显然，喜马拉雅山和印度夏季风对喜马拉雅山以南的臭氧量有很强的抑制作用，而寒冷的西伯利亚反气旋的入侵往往会带来中国和日本上空更大的臭氧量。1957年印度北部上空臭氧的季节变化具有不寻常的特征。RAMANATHAN(1954)在国际气象协会罗马会议上总结了1954年以前在印度进行的臭氧测量结果。在一年中的大部分时间里，臭氧的日常变化很小，地表天气条件似乎对它们没有影响。然而，在12月至4月，在阿布山和新德里上空的臭氧有显著的变化，这是活跃的西方扰动穿过印度北部的时期。臭氧从秋季最小值到冬季和春季相对较高值的转变发生在一连串的浪涌中，第一次浪涌大约与印度北部强高空西风带的出现一致。一些明显的浪涌与6公里和9公里处的低压槽通过有关。当西北风取代西南风时，臭氧量就会上升，但一旦西北风稳定下来，臭氧量就会开始下降。1959年7月在牛津举行的国际臭氧研讨会上发表的论文。86 r。N. Kulkarni, P. D. Angreji和K. R. Ramanathan在第X卷第2卷中解释了引航气球高度风向的变化。在冬季和春季，即使在低至20°N的纬度地区，也可观测到与高层大气波有关的臭氧中纬度变化。后来在德里、阿布山和奎达进行的观测证实了臭氧变化与西方扰动的联系。自1955年以来，在斯利那加(34°N)这个双对流层频繁出现的纬度，对臭氧总量及其垂直分布进行了观测。1955年5月，在斯利那加建立了一个臭氧观测站，将多布森分光光度计转移到那里。重新校准了分光光度计的光楔并测定了常数。在随后的一段时间里，经常检查校准。本文载有迄今分析的臭氧观测结果的摘要。决定在本研究中使用在波长对3114/3324 (CC’)上观测到的下午臭氧量。臭氧值是按照RAMANATHAN和KARANDIKAR(1949)提出的方法计算和校正的。为了均匀起见，所有臭氧值都转换为VIGROUX的臭氧吸收系数a水平。1. 图1给出了1957- 1958年印度三个站点的日臭氧值，分别是阿布山(24°N)、新德里(28V2°N)和斯利那加(34°N)。图中还包括了日本馆野(36°N)上空1957- 1958年的日臭氧量。1959年1957- 1958年臭氧量的比较87该图的一个显著特征是，尽管Tateno的纬度与斯利那加的纬度只相差2°，但在冬季和春季，Tateno的臭氧值远高于斯利那加。Tateno上空臭氧含量的波动也明显大于斯利那加上空。然而，8月至10月，馆野上空的臭氧含量仅略高于印度北部监测站。12月，馆野臭氧开始与印度值分离，差异迅速扩大。2. 图2为1955年7月至1958年12月在泰特诺、斯利那加、新德里和阿布山的10天平均臭氧值。(1)总体上，季节变化符合适合中纬度地区的正常变化规律，冬春季最大，夏季最小
{"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}
Pub Date : 2012-01-01DOI: 10.2467/mripapers1950.23.2_136
T. Kizawa
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.
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