An Application of the Multi-Physics Ensemble Kalman Filter to Typhoon Forecast     

Chanh Kieu  Pham Thi Minh  Hoang Thi Mai 《Pure and Applied Geophysics》2014,171(7):1473-1497

This study examines the roles of the multi-physics approach in accounting for model errors for typhoon forecasts with the local ensemble transform Kalman filter (LETKF). Experiments with forecasts of Typhoon Conson (2010) using the weather research and forecasting (WRF) model show that use of the WRF’s multiple physical parameterization schemes to represent the model uncertainties can help the LETKF provide better forecasts of Typhoon Conson in terms of the forecast errors, the ensemble spread, the root mean square errors, the cross-correlation between mass and wind field as well as the coherent structure of the ensemble spread along the storm center. Sensitivity experiments with the WRF model show that the optimum number of the multi-physics ensemble is roughly equal to the number of combinations of different physics schemes assigned in the multi-physics ensemble. Additional idealized experiments with the Lorenz 40-variable model to isolate the dual roles of the multi-physics ensemble in correcting model errors and expanding the local ensemble space show that the multi-physics approach appears to be more essential in augmenting the local rank representation of the LETKF algorithm rather than directly accounting for model errors during the early cycles. The results in this study suggest that the multi-physics approach is a good option for short-range forecast applications with full physics models in which the spinup of the ensemble Kalman filter may take too long for the ensemble spread to capture efficiently model errors and cross-correlations among model variables.  相似文献   

Sediment distribution and depositional processes along the fluvial to marine transition zone of the Mekong River delta,Vietnam     

Marcello Gugliotta  Yoshiki Saito  Van Lap Nguyen  Thi Kim Oanh Ta  Toru Tamura 《Sedimentology》2019,66(1):146-164

The area of coastal rivers with a combination of fluvial, tidal and wave processes is defined as the fluvial to marine transition zone and can extend up to several hundreds of kilometres upstream of the river mouth. The aim of this study is to improve the understanding of sediment distribution and depositional processes along the fluvial to marine transition zone using a comprehensive dataset of channel bed sediment samples collected from the Mekong River delta. Six sediment types were identified and were interpreted to reflect the combined action of fluvial and marine processes. Based on sediment‐type associations, the Mekong fluvial to marine transition zone could be subdivided into an upstream tract and a downstream tract; the boundary between these two tracts is identified 80 to 100 km upstream of the river mouth. The upstream tract is characterized by gravelly sand and sand and occasional heterolithic rhythmites, suggesting bed‐load supply and deposition mainly controlled by fluvial processes with subordinate tidal influence. The downstream tract is characterized by heterolithic rhythmites with subordinate sand and mud, suggesting suspended‐load supply and deposition mainly controlled by tidal processes with subordinate fluvial influence. Sediment distributions during wet and dry seasons suggest significant seasonal changes in sediment dynamic and depositional processes along the fluvial to marine transition zone. The upstream tract shows strong fluvial depositional processes with subordinate tidal influence during the wet season and no deposition with weak fluvial and tidal processes during the dry season. The downstream tract shows strong coexisting fluvial and tidal depositional processes during the wet season and strong tidal depositional processes with negligible fluvial influence during the dry season. Turbidity maxima are present along the downstream tract of the fluvial to marine transition zone during both wet and dry seasons and are driven by a combination of fluvial, tidal and wave processes.  相似文献   

The Nui Chua layered peridotite-gabbro complex as manifestation of Permo-Triassic mantle plume in northern Vietnam     

G.V. Polyakov  R.A. Shelepaev  Tran Trong Hoa  A.E. Izokh  P.A. Balykin  Ngo Thi Phuong  Tran Quoc Hung  Bui An Nien 《Russian Geology and Geophysics》2009,50(6):501-516

New data on the age, composition, formation conditions, and ore-geochemical specialization of the Nui Chua layered peridotite-gabbro complex are reported. They evidence that the complex resulted from the Permo-Triassic mantle plume activity in northern Vietnam (southern framing of the Yangtze Platform). Two series of mafic and ultramafic rocks differing in ore productivity—layered (PGE-Cu-Ni) and pegmatoid (Fe-Ti-V)—have been recognized within the complex. The first estimates of the composition of their parental melts have been obtained.  相似文献   

Polycyclic aromatic hydrocarbons from rural household biomass burning in a typical Chinese village     

HaiLin Wang  YaHui Zhuang  ZhengPing Hao  MeiQiu Cao  JinXian Zhong  XiaoKe Wang  Thi Kim Oanh Nguyen 《中国科学D辑(英文版)》2008,51(7):1013-1020

Biomass energy sources are still popular in the rural areas of developing countries for cooking and space heating. Since the incomplete combustion of agricultural residues in home-made ranges might lead to both outdoor and indoor air pollution and cause potential health threat to the rural population, we monitored the ambient levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) at a typical rural site. Ambient particulate PAH samples (PM2.5 and PM10) were taken during both cooking and non-cooking periods. Source emission monitoring was also conducted for both improved and tra- ditional cooking stoves used in the area. Ambient PAHs had a significant increase during the cooking periods and varied from 72.1 to 554.4 ng/m3. The highest total PAH levels were found during the supper cooking time, in which five- and six-ring species accounted for a large proportion. The observed PAH levels during cooking periods at this rural site were even higher than those in urban areas. A good correlation was found between the benzo[a]pyrene level and the total PAH concentration (r=0.98), making benzo[a]pyrene a potential molecular marker for PAH pollution in the rural areas, where bio- mass burning is typical. The profiles of the particulate PAHs in both ambient air and source emissions showed a high proportion of high molecular-mass PAHs. In addition, emission factors of 16 PAHs from an improved household stove were found to be significantly lower than those from traditional stoves used in China and in other Asian countries.  相似文献   

Total organic carbon fluxes of the Red River system (Vietnam)   总被引：1，自引：0，他引：1       下载免费PDF全文

Thi Phuong Quynh Le  Viet Nga Dao  Emma Rochelle‐Newall  Josette Garnier  XiXi Lu  Gilles Billen  Thi Thuy Duong  Cuong Tu Ho  Henri Etcheber  Thi Mai Huong Nguyen  Thi Bich Ngoc Nguyen  Bich Thuy Nguyen  Nhu Da Le  Quoc Long Pham 《地球表面变化过程与地形》2017,42(9):1329-1341

Riverine transport of organic carbon from terrestrial ecosystems to the oceans plays an important role in the global carbon cycle. The Red River is located in Southeast Asia where river discharge, sediment loads and fluxes of elements (carbon, nitrogen and phosphorus) associated with suspended solids have been dramatically altered over past decades as a result of reservoir impoundment and land use, population, and climate change. Dissolved organic carbon (DOC) and particulate organic carbon (POC) concentrations were measured monthly at four stations of the Red River system from January 2008 to December 2010. The results reveal that POC changed synchronically with total suspended solids (TSS) concentration and with the river discharge, whereas no clear trend was observed for DOC concentration. The mean value of total organic carbon (TOC = DOC + POC) flux in the delta of the Red River was 31.5 × 10¹³ ± 4.0 × 10¹³ MgC.yr^?1 (range 27.9–35.8 × 10¹³ MgC.yr^?1 which leads to a specific TOC flux of 2012 ± 255 kgC.km^?2.yr^?1 during this 2008–2010 period. About 80% of the TOC flux was transferred to the estuary during the rainy season as a consequence of the higher river water discharge. The high mean value of the POC:Chl‐a ratio (1585 ± 870 mgC.mgChl‐a^?1) and the moderate C:N ratio (7.3 ± 0.1) in the water column system suggest that organic carbon in the Red River system is mainly derived from erosion and soil leaching in the basin. The effect of two new dam impoundments in the Red River was also observable with lower TOC fluxes in 2010 compared with 2008. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Tropical Cyclone in the North of the South China Sea as a Factor Affecting the Structure of the Vietnamese Current     

Vlasova  G. A.  Xuan  Nguyen Ba  Demenok  M. N.  Long  Bui Hong  Mau  Le Dinh  Dung  Nguyen Thi Thuy 《Izvestiya Atmospheric and Oceanic Physics》2020,56(4):390-400

Izvestiya, Atmospheric and Oceanic Physics - Tropical cyclones play a significant role in the formation of the hydrodynamic regime of the South China Sea, including its western part, which is...  相似文献   

Economic reforms and the New Master Plan of Ho Chi Minh City, Vietnam: Implementation issues and policy recommendations   总被引：1，自引：0，他引：1  

Huong Ha  Tai-Chee Wong 《GeoJournal》1999,49(3):301-309

The economic reforms or `doi moi' introduced in 1986 have transformed Vietnam's planned economy to a more market-oriented one. Rise in international capital, market liberalisation and greater population mobility have contributed towards a greater concentration of squatters in the city centre, and extended metropolitan development in the fringes of Ho Chi Minh City. Rapid urbanisation and, to a lesser extent, industrialisation have converted large tracts of farmlands to urban use, and greater rural exodus. Such dramatic changes have drawn the city government's attention to face the new challenges. As a very important political and economic centre in the south, Ho Chi Minh City has prepared for itself a new Master Plan, approved in 1997, to provide a legitimate and institutional framework to guide its future spatial development. This paper introduces the background and explains the rationale behind the drafting of the Master Plan, and highlights the constraints that are expected in implementing it. The administrative framework in planning is also examined in terms of its advantages and disadvantages in a planning system with four levels: national, provincial, district and local. Land availability in the city centre, source of funding and technical expertise are all parts and parcels of the challenges in the process of modernising HCMC to accommodate the need of its residents and rapid global change. Ho Chi Minh City's strong relationships with its hinterlands have equally required the planners to look at the planning field using the whole national and regional scenarios. Policy recommendations aimed at improving the implementation capability are finally presented. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Effects of warming on microbial communities in the coastal waters of temperate and subtropical zones in the Northern Hemisphere,with a focus on Gammaproteobacteria     

Dao Thi Anh Tuyet  Toshinari Tanaka  Rumi Sohrin  Do Manh Hao  Kazuyo Nagaosa  Kenji Kato 《Journal of Oceanography》2015,71(1):91-103

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Energy consumption,CO2 emissions and GDP in Nigeria     

Sulaiman Chindo  Abdulsamad Abdulrahim  Salisu Ibrahim Waziri  Wong M. Huong  Abdulfatah Abubakar Ahmad 《GeoJournal》2015,80(3):315-322

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Neogene freshwater stromatolites of Vietnam     

A. R. Geptner  V. V. Petrova  Phan Dong Pha  Nguyen Xuan Huyen  Le Thi Nghinh  Nguyen Minh Quang 《Doklady Earth Sciences》2012,443(2):436-438

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