Hirose K.,Sophia University |
Kikawada Y.,Sophia University |
Igarashi Y.,Meteorological Research Institute |
Fujiwara H.,Japan National Institute for Agro - Environmental Sciences |
And 4 more authors.
Journal of Environmental Radioactivity | Year: 2016
Plutonium (238Pu and 239,240Pu), 137Cs and plutonium activity ratios (238Pu/239,240Pu) as did uranium isotope ratio (235U/238U) were measured in surface soil samples collected in southeast Mongolia. The 239,240Pu and 137Cs concentrations in Mongolian surface soils (<53 μm of particle size) ranged from 0.42 ± 0.03 to 3.53 ± 0.09 mBq g-1 and from 11.6 ± 0.7 to 102 ± 1 mBq g-1, respectively. The 238Pu/239,240Pu activity ratios in the surface soils (0.013-0.06) coincided with that of global fallout. The 235U/238U atom ratios in the surface soil show the natural one. There was a good correlation between the 239,240Pu and 137Cs concentrations in the surface soils. We introduce the migration depth to have better understanding of migration behaviors of anthropogenic radionuclides in surface soil. We found a difference of the migration behavior between 239,240Pu and 137Cs from 137Cs/239,240Pu - 137Cs plots for the Mongolian and Tsukuba surface soils; plutonium in surface soil is migrated easier than 137Cs. © 2016 Elsevier Ltd.
Sugimoto N.,Japan National Institute of Environmental Studies |
Hara Y.,Japan National Institute of Environmental Studies |
Yumimoto K.,Kyushu University |
Uno I.,Kyushu University |
And 2 more authors.
Scientific Online Letters on the Atmosphere | Year: 2010
Dust emission estimated with a 4D-Var data assimilation system using ground-based lidar network data was compared with vegetation growth data based on visual observations in the Gobi desert in Mongolia in the spring of 2007. The dust emission flux estimated with the data assimilation system was less than that estimated without data assimilation in the dust event of May 21-30 and was the opposite in the event of March 25-April 3. The threshold surface friction velocity estimated from the results of the data assimilation was less than 0.3 m s-1 in the dust event of March 25-April 3 and was ~0.36 m s-1 in the event of May 21-30. The difference between the two events was qualitatively explained by the vegetation growth data. The accumulated precipitation during the period was ~2 mm. The results show that vegetation growth with slight precipitation in the Gobi desert may significantly reduce dust emission. © 2010, the Meteorological Society of Japan.
Jersabek C.D.,University of Salzburg |
Jersabek C.D.,Academy of Natural Sciences of Philadelphia |
Bolortsetseg E.,Institute of Meteorology and Hydrology
Proceedings of the Academy of Natural Sciences of Philadelphia | Year: 2010
A list of monogonont rotifers that have São far been found in Mongolia has been compiled, based on recent collections and previously published records. For all species, detailed information is provided on their occurrence in Mongolia, along with notes on their world distribution and autecology. To date, 246 species and infraspecific taxa in 55 genera are known, including 16 potentially new, as yet undescribed species.
Prakash S.,Atmospheric and Oceanic science Group |
Mahesh C.,Atmospheric and Oceanic science Group |
Gairola R.M.,Atmospheric and Oceanic science Group |
Buyantogtokh B.,Institute of Meteorology and Hydrology
International Journal of Hydrology Science and Technology | Year: 2012
Rainfall forecast has prime importance in an agrarian country like India, wherein the agricultural production is solely dependent on monsoon rainfall. In this paper, an artificial neural network (ANN) technique is used to construct a non-linear mapping between output data from global forecast system (GFS) and rainfall from tropical rainfall measuring mission (TRMM) satellite measurements. The objective of the present study is to generate region-specific six-hourly quantitative rainfall forecast over central India using ANN and resilient propagation learning algorithm. Meteorological variables from the GFS model and precipitation product from TRMM multisatellite precipitation analysis (TMPA) are used as input data for training the network, which generate rainfall forecast for the next time step. The test was performed for central India during the summer monsoon period of 2010. In order to evaluate the potential of rainfall forecast skill over the studied region, the forecast precipitation has been intercompared with TMPA-3B42, and Kalpana-1 derived precipitation products and a statistical analysis was performed. The linear correlation between ANN forecast and TMPA-3B42 rainfall was 0.58, whereas it was 0.52 with Kalpana-1 derived precipitation estimates. The results show that the predicted precipitation by the present technique performs better than GFS model precipitation forecast, and the system indicates a potential for more accurate rainfall forecasting. Copyright © 2012 Inderscience Enterprises Ltd.
Jugder D.,Institute of Meteorology and Hydrology |
Jugder D.,Tottori University |
Sugimoto N.,Japan National Institute of Environmental Studies |
Shinoda M.,Tottori University |
And 3 more authors.
Atmospheric Environment | Year: 2012
Polarization-sensitive Mie-scattering lidars were installed for dust storm monitoring at Sainshand and Zamyn-Uud in the Gobi Desert and at the Mongolian capital city of Ulaanbaatar in 2007. We studied the temporal and spatial distributions and transportation of dust, elevated dust, biomass burning smoke, and anthropogenic aerosol by using lidar measurements from the end of 2007 to the first half of 2010. The study results show that the maximum height of dust layers over the Gobi Desert of Mongolia during dust event periods varied from 0.5 to 5.5 km above the ground level (AGL). The 95th percentile level of dust vertical distribution was found at 4 and 4.5 km for Zamyn-Uud and Sainshand, respectively. The averaged maximum height of dust layers during dust events was 2.0-2.2 km AGL at those Gobi sites. The lidar measurements also revealed transport of dust layers elevated in the atmosphere. Base heights of elevated dust layers varied from 0.5 to 2.5 km AGL, while maximum heights from 2.5 to 4.5 km AGL. Backward air trajectory analyses suggested source areas of the elevated dust that transported from other source regions to southeastern Mongolia. A detail study was conducted of the dust event in 19-20 May 2008. Hourly maximum dust concentrations of PM10 (PM2.5) reached 1139-1409 (384-404) μg m-3 during the dust event episode. Dust concentration of PM10 had high correlations with visibilities. Threshold winds for dust emission were determined at Sainshand and Zamyn-Uud. The lidar measurements at the three sites detected vertical profiles of biomass burning smoke and anthropogenic aerosol with top heights of 3-4 km AGL. © 2012 Elsevier Ltd.