oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Fractal Characteristics and Trend Forecast of Dust-Storms and Severe-Dust-Storms in Northern China
我国北方沙尘暴与强沙尘暴过程的分形特征及趋势预测

YIN Xiao-hui,WANG Shi-gong,
尹晓惠
,王式功

中国沙漠 , 2007,
Abstract: Dust-storm is a kind of common harmful weather phenomenon. A lot of domestic and international experts and scholar have paid close attention to the prediction of them due to the high frequency and severe calamity of dust-storms. This paper first reviewed the international progress of relevant research, and then analyzed the fractal characteristics of dust-storms and severe-dust-storms in recent 49 years in Northern China according to the observed data from 1954 to 2002. Finally, we used the R/S analytical method to predict the variation tendency of them. The results showed that the dust-storm and severe-dust-storm events have an approximate unanimous variation tendency; namely, the occurrence of dust-storm and severe-dust-storm reduced gradually since 1950s but increased relatively in recent years. The temporal sequences of dust-storms and severe-dust-storms in Northern China have fractal characteristics. The correlative dimensions are 2. 64 and 3.34, and the average predictable periods are 7-8 years and 8-9 years respectively. The Hurst indexes can reflect the rules of dust-storms and severe- dust-storms in Northern China very well. According to the indexes and the .variation tendency of dust-storm and severe-dust- storm, we can predict that the occurrence of dust-storm in Northern China will increase first and reduce next from 2002 to 2010 and the occurrence of severe-dust-storms will have a similar trend from 1999 to 2008.
A Statistical Model for Long-Term Forecasts of Strong Sand Dust Storms  [PDF]
Siqi Tan, Moinak Bhaduri, Chih-Hsiang Ho
Journal of Geoscience and Environment Protection (GEP) , 2014, DOI: 10.4236/gep.2014.23003
Abstract:

Historical evidence indicates that dust storms of considerable ferocity often wreak havoc, posing a genuine threat to the climatic and societal equilibrium of a place. A systematic study, with emphasis on the modeling and forecasting aspects, thus, becomes imperative, so that efficient measures can be promptly undertaken to cushion the effect of such an unforeseen calamity. The present work intends to discover a suitable ARIMA model using dust storm data from northern China from March 1954 to April 2002, provided by Zhou and Zhang (2003), thereby extending the idea of empirical recurrence rate (ERR) developed by Ho (2008), to model the temporal trend of such sand dust storms. In particular we show that the ERR time series is endowed with the following characteristics: 1) it is a potent surrogate for a point process, 2) it is capable of taking advantage of the well developed and powerful time series modeling tools and 3) it can generate reliable forecasts, with which we can retrieve the corresponding mean number of strong sand dust storms. A simulation study is conducted prior to the actual fitting, to justify the applicability of the proposed technique.

Dust Storms in North China in 2002: A Case Study of the Low Frequency Oscillation
Dust Storms in North China in 2002: A Case Study of the Low Frequency Oscillation

FAN Ke,WANG Huijun,
FAN Ke
,WANG Huijun

大气科学进展 , 2007,
Abstract: The low frequency oscillation in both hemispheres and its possible role in the dust weather storm events over North China in 2002 are analyzed as a case study. Results show that the Aleutian Low is linked with the Circumpolar Vortex in the Southern Hemisphere on a 30-60-day oscillation, with a weak Circumpolar Vortex tending to deepen the Aleutian Low which may be helpful for the generation of dust storm events.The possible mechanism behind this is the inter-hemispheric interaction of the mean meridional circulation,with the major variability over East Asia. The zonal mean westerly wind at high latitudes of the Southern Hemisphere in the upper level troposphere may lead that of the Northern Hemisphere, which then impacts the local circulation in the Northern Hemisphere. Thus, the low frequency oscillation teleconnection is one possible linkage in the coupling between the Southern Hemisphere circulation and dust events over North China. However, the interannual variation of the low frequency oscillation is unclear.
Analysis of the severe group dust storms in eastern part of Northwest China

ZHOU Zijiang,WANG Xiwen,

地理学报 , 2002,
Abstract: Based on the available original dust storm records from 60 meteorological stations, we discussed the identification standard of severe dust storms at a single station and constructed a quite complete time series of severe group dust storms in the eastern part of Northwest China in 1954-2001. The result shows that there were 99 severe group dust storms in this region in recent 48 years. The spatial distribution indicates that the Alax Plateau, most parts of the Ordos Plateau and most parts of the Hexi Corridor are the main areas influenced by severe group dust storms. In addition, the season and the month with the most frequent severe group dust storms are spring and April, accounting for 78.8% and 41.4% of the total events respectively. During the past 48 years the lowest rate of severe group dust storms occurred in the 1990s. Compared with the other 4 decades, on the average, the duration and the affected area of severe group dust storms are relatively short and small during the 1990s. In 2000 and 2001, there were separately 4 severe group dust storms as the higher value after 1983 in the eastern part of Northwest China.
Regional characteristics of dust events in China

WANG Shigong,WANG Jinyan,ZHOU Zijiang,SHANG Kezheng,YANG Debao,ZHAO Zongsuo,

地理学报 , 2003,
Abstract: The regional characteristics of dust events in China has been mainly studied by using the data of dust storm, wind-blown sand and floating dust from 338 observation stations through China from 1954 to 2000. The results of this study are as follows: (1) In China, there are two high frequent areas of dust events, one is located in the area of Minfeng and Hotan in the South Xinjiang Basin, the other is situated in the area of Minqin and Jilantai in the Hexi Region. Furthermore, the spatial distributions of the various types of dust events are different. The dust storms mainly occur in the arid and semiarid areas covering the deserts and the areas undergoing desertification in northern China. Wind-blown sand and floating-dust not only occur in the areas where dust storms occur, but also extend to the neighboring areas. The range of wind-blown sand extends northeastward and southeastward, but floating-dust mainly extends southeastward to the low-latitude region such as the East China Plain and the area of the middle and lower reaches of the Yangtze River. Compared with wind-blown sand, the floating-dust seldom occurs in the high latitude areas such as North Xinjiang and Northeast China. (2) The affected areas of dust storms can be divided into seven sub-regions, that is, North Xinjiang Region, South Xinjiang Region, Hexi Region, Qaidam Basin Region, Hetao Region, Northeastern China Region and Qinghai-Xizang (Tibet) Region. The area of the most frequent occurrence of dust storms and floating-dust is in South Xinjiang Region, and of wind-blown sand in the Hexi Region. In general, the frequency of dust events in all the seven regions shows a decreasing tendency from 1954 to 2000, but there are certain differences between various dust events in different regions. The maximum interannual change and variance of dust events during this time happened in South Xinjiang Region and Hexi Region. The dust events generally occur most frequently in April in most parts of China. The spring occurred days of dust events occupied 60-70% of the whole year in Hetao Region and Northeastern China Region. However, in South Xinjiang Region and North Xinjiang Region, which was less affected by monsoon climate, dust events may occur at any time of the year, less than 50% of the events in this region occur during spring. In the remaining three regions 50-60% of the dust events occur in spring of a year.
Analysis and Comparison of AVHRR Land Surface Temperature in the Dust Storm Weather with TSP/PM10 Data
沙尘发生期遥感反演地表温度与实测沙尘数据之间的比较分析

Han Xiuzhen,Dong Chaohu,Ma Lan,Luo Jingning,Li Yajun,Zhang Xiaohu,
韩秀珍
,董超华,马岚,罗敬宁,李亚军,张晓虎

气候与环境研究 , 2004,
Abstract: In spring of 2002, several dust storms occurred in the northern China, which brought difficulty to people's life and production, and attracted the attention of many Asian countries. This work compared the trend of AVHHR LST temporal change with that of TSP data in March 2002. Corresponding relation was found between the two. The conclusion is that spacecraft observation provides an important data source for dust storm study.
Study and case simulation of a regional dust model coupled with a nonhydrostatic dynamics model
Conglan Cheng,Yingchun Wang,Weidong Liu,Xiaoling Zhang,Xiaofeng Xu,Pu Xie
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03185785
Abstract: A new regional dust model suitable for simulation and forecasting of dust storms over northern China was described. The dust model was developed by coupling the mesoscale dynamics model MM5 (the Fifth-Generation NCAR/Penn State Mesoscale Model) with a set of mass conservation equations for the particles. The model includes all the atmospheric physical processes of dust storms including occurrence, lifting, transport, and dry and wet deposition. It considers the parameterization of dry and wet deposition, the dust size distribution and microphysical processes in detail. The dust flux from the surface is parameterized based on the friction velocity, which is provided by the mesoscale nonhydrostatic dynamics model, which takes account of the vegetation coverage, land use, soil category, and soil moisture. This new dust model is used to simulate the dust storm that occurred on 19–21 March, 2002 in North China. The results show that there is high dust concentration and its movement is consistent with the surface weather record and satellite monitoring images of the observed dust storm. The simulated dust concentration coincides with the observation data of the particulate concentration of PM10 (dust particles smaller than 10 um in diameter). The new numerical model also successfully simulates the formation and migration of the dust storm of 6–8 April, 2002 in North China.
Rocket dust storms and detached dust layers in the Martian atmosphere  [PDF]
Aymeric Spiga,Julien Faure,Jean-Baptiste Madeleine,Anni M??tt?nen,Fran?ois Forget
Physics , 2012, DOI: 10.1002/jgre.20046
Abstract: Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low-latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high-altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.
Several Scientific Issues of Studies on the Dust Storms
沙尘暴研究中的若干科学问题

Shi Guangyu,Zhao Sixiong,
石广玉
,赵思雄

大气科学 , 2003,
Abstract: During the recent years much more dust storm events occurred in Northern China. This has aroused general concern. In fact, dust storms do not only have effects on the air quality, traffic etc. , and cause soil erosion and damages of human being and domestic animals, but as a special species of atmos-pheric aerosols dust (or soil) particles also have significant climate and environment effects. This paper will briefly review the studies on the dust storms and some scientific issues which need to be investigated will be emphasized.
Sand-dust storms in China: temporal-spatial distribution and tracks of source lands
QIU Xin-fa,ZENG Yan,MIAO Qi-long,

地理学报(英文版) , 2001,
Abstract: Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published on Surface Meteorological Monthly Bulletin and Surface Chart during 1971-1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in China. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into China across the Sino-Mongolian border from Hami, a city in the eastern part of Xinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into China from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.