The concept and category of wind-sand engineering were discussed in this paper. The development processes of wind-sand engineering in China were reviewed preliminarily. Based on different regional environments, wind-sand engineering research in our country can be divided into two parts: aeolian research of major engineering in desert areas, and aeolian research of major engineering in other areas with special environment. Further than that, aeolian research of major engineering in desert areas can be divided into 4 stages, and aeolian research of major engineering in other areas with special environment mainly focuses on tropical coastal areas, Tibet Plateau and gobi in arid areas. Our research suggests that the development trends of major wind-sand engineering can be summarized as the following aspects. \mathrm{①} Revealing principles of the wind-sand engineering shelter systems; \mathrm{②} Evaluating environmental effects of the major wind-sand engineering; \mathrm{③} Functions of the wind-sand engineering transforming from simple sand prevention to eco-economic types shelter systems; \mathrm{④} A kind of treatment technology with fabricated materials and equipped construction processes needs to be studied urgently, which can make sand prevention with rapid pace, high efficiency and high quality.

Atmospheric bioaerosols have great impact on the global climate, air quality, atmospheric process and human health. The dust events have a role in transporting bioaerosols and affecteing the concentration and property of bioaerosols in the downwind area by facilitating long-distance dispersal events every year. This paper reviewed the study progress on the concentration, characteristics and distribution of bioaerosols in dust weather. The references showed that the ratio of different kind of bioaerosols changed in dust weather with the changing of contribution of bacteria and fungi. The concentration of cultural bacteria, fungi and the total microbes increased on dust days. However, the increase ratio was different for different microbes in different areas. Microbes in bioaerosols mainly distributed in coarse particles; the size distribution of bioaerosols was affected greatly by dust events with different variation for different kinds of bioaerosols. The microbial community and predominant species of microorganism in bioaerosols changed in dust weather. The impact and mechanism of dust on the concentration, size distribution, microbial community and activity of bioaerosols need to be studied further.

Controlled by the landscape pattern of oasis and desert,the oasis-desert transitional zone is very sensitive to the change of environmental conditons. The processes of wind-blown sand in the oasis-desert transitional zone have direct impact on the stability and development of oasis. Local circulation and microclimate induced by the gradient differences of environment factors between oasis and desert such as vegetation, relief, underlying surface, hydrographic and meteorological factors and so on have restricted the back and forward of desert or the transition of oasis. This paper summarizes the latest research achievements in such six aspects that include local climate, soil erosion, sand storms, aeolian environments, sand transport and prevention system of sand damages. It is expected to solve the problems of sand damages and ensure ecological safety of oasis. Moreover, it will provide scientific evidence for establishing the oasis-protection system in arid region,which is both significant in theory and in practice.

Aeolian processes and the related material transports are the key land surface process, which play a major role in the ecologicial environments. This paper generialized the mechanisms of nutrient emission, transport, and deposition of the blown wind materials in arid and semiarid regions. Based on the results of enormous previous studies, the componets of the nutrients and materials, the source-sink models of the aeolian transports, the influence of nutrient loss and depositions on vegetation growth, reallocations and utilizations of the nutrients within wind blown materials on phytocommunity development, the responses of phytocommunity development to the aeolian transports in arid and semiarid regions were discussed. Finally, based on the current results of studies our colleagues acquired, pointed out that the researches in the near future may reveral the deposition mechanisms of aeolian materials in different terrestrial ecologicial systems, appraise the composition and effect contents of the nutrients, highlight the dominant transporting routes of the aeolian nutrients, found the source-sink models of the nutrients, analyze the responses between the aeolian activity and vegetation formation, and by adopting the integrated qualitative and quantitative methodologies understand the dynamic relationships between the aeolian activity and vegetation evolution. The related studies may further improve the understanding of the roles of the aeolian transport on terrestrial ecosystem evolution, thereby providing new evidence for the theories of arid geomorphology and providing academic supports for local ecological remediation of arid and semiarid regions.

Crust is a compact soil layer which distributes widely in arid and semi arid region to resist wind erosion. In this paper the model of crust destruction in wind erosion is suggested to study the crust destruction mechanics, and crust life length is forecasted. Dimensional analysis is applied to establish the constitutive equation of crust wind erosion volume with sand continuous impacting. The numerical calculation results show that crust life length is effected obviously by sand impacting velocity，sand rotational angular velocity，sand impacting angle，sand diameter,dust-storms datasets and its duration. Through statistic analysis and calculation with above influencing factors, the crust life length is 3~8 years and 5.3 years average when the crust thickness is 20 mm. This research can make people more deeply understand natural destruction features of crust, which has important theoretical significance and practical application value in sand-protecting and sandbinding.

 In this paper, the characteristics between the decadal variation of sand-storm in north China and decadal variability of thermohaline circulation (THC) in recent 50 years are analyzed. It is found that there are some relationships between the sand-dust storm and THC. Further analyses indicate the primary process of this following relationship:  THC influences on NAO, NAO on Siberia high, Siberia high on cold air activities, and then, on the sanddust storm. The results show that when THC is strong (weak), NAO is weak (strong), Siberia and north winds  in surface are strong (weak), sanddust storms are more (less). Moreover, a remarkable variation from the end of the 1970’s to the beginning of 1980’s is also found that THC, Siberia high and north wind changed from strong to weak, NAO from weak to strong and sanddust storm in north China obviously decreased.

Threshold friction velocity  u_*t or threshold velocity  u_t represents the erodibility of soil and is the critical factor for dust emission into the atmosphere. It is also one of the most important parameters in dust emission schemes, and can be determined via three widely used methods, namely, observation through field experiments, model parameterization and statistical calculation. The results obtained by different methods can be compared and validated. The dust emission criterion could be established and the parameterization schemes for dust emission threshold could be improved based on the results of field experiments. This paper has reviewed the results, applications, representation and differences of various methods. The remaining problems and suggestions in the future have been pointed out.

In this paper, new research advances and representative productions about the temporal and spatial characterastics of sand-dust storm and the relationship between sand-dust storm and arid in China are briefly reviewed and summarized. The mechanism of the formation of sand-dust storm and the interaction between sand-dust and arid is also discussed. 

Based on data (1951-2000) from the 188 meteorological observation stations and the NDVI data (1983-2000) from EROS data center from1983 to 2000, the authers analyzed the impact factors of dust storm in northern China, and arrived at the main conclusions as follows: (1) Among the natural factors which affect the occurrence, development and evolution of dust storm, vegetation coverage, precipitation, windy days and temperature play a critical role. The summer vegetation coverageaffects the occurrence frequency of the following spring season. Precipitation and temperature have direct impact on the dust storm related groundparameters such as vegetation coverage. (2) Windy days and temperature are composed of the impetus factors of dust storm, and vegetationcoverage and precipitation are the main resistance factors. The changes of the dust storm days and duration mainly depend on theintegrated affection of the impetus factors and the resistance factors. (3) The fundamental measures to reduce dust storm disaster is not to deal with dust storm itself, but to eliminate the social impact which caused land and ecological degradation and to achieve the harmony development among social, economic and eco-environmental construction.

Simulation of dust emission flux is very fundamental for evaluating climatic effects of dust aerosols and controlling desertification process and dust storm. The two shear stress partition models were proposed by Marticorena and Alfaro respectively for evaluating effect of roughness elements on dust production. The existing problems of them are discussed on basis of sensitive tests, previous wind tunnel and field experiments. First, the influence of porosity and spatial heterogeneity of roughness elements on shear stress partition was not taken into account because all equations about roughness length can not involve such factors as porosity and spatial heterogeneity of roughness elements. However, it is proved that these factors cannot be neglected by many experiments. Second, the result from sensitive test of Marticorena's Model is in disagreement with that of Alfaro's Model, implying that the models need to be investigated further by wind tunnel experiment. Third, regarding the roughness length to efficiently suppress wind erosion, the values predicted respectively by the models are questioned by some wind erosion experiment data, therefore the relationship between shear stress partition and roughness length need to be reassessed. In terms of these problems of the models, two approaches are proposed: improving roughness length formula and tuning empirical constants of the models by wind tunnel experiment.

Soil water content was observed continuously and automatically in Erlianhaote, Wulatezhongqi and Wuhai, northwestern Inner Mongolia, China for two years (2002-2003) in this paper. Based on the data, the temporal variation of soil water content was analyzed, which represented the characteristics of land surface. The effect on soil water content) influenced by atmosphere in different soil texture (Brown-calcium soil, Chestnut--calcium soil and Gray-desert soil) was compared. Seasonal variations of the soil water content were characterized into three stages, from thawing to active dust storm (spring), rainy (autumn) and snow cover (winter) period. The soil water content much depended on meteorology condition. By these observations, it became clear that the soil water content was the lowest in the beginning thaw period, and was the highest in the rainy season. Differences in soil water content among the years depended on the lowest in the whole thaw period meteorological conditions The soil water content was lowest during the soil melt period, the variations of Chestnut-calcium soil was obvious under meteorology condition. The dust emission much influenced by thaw time of soil, soil wetness and the thaw period and depth of frozen soil.

A sand-dust numerical model coupled with GRAPES (Global/Regional Assimilation and Prediction Enhanced System)－GRAPES_SDM is introduced. GRAPES_SDM includes such detail physical processes as dust emission, transport, dry deposition and clear sky process, which can simulate and forecast the initial and sand-dust concentration of sand and dust storm. Based on GRAPES_SDM, a numerical model forecasting system is established in northwest China, and is applied to Lanzhou Center Meteorological Observatory for operational prediction of sand and dust storm from April, 2005. Two severe sand and dust storms occurred in 17-19, April, 2005 and 28-29, May, 2005 in northwest China are choosed to simulate there initial, transport, dust emission and disappear. The results show no difference for sand-dust spetial distribution between model outputs and remote sensing monitoring imageres, which indicates that the model system has the capability of forecasting sand and dust storm in northwest China.

Based on the Micaps meteorology data provided by China Meteorological Administration, the source, movement route, influence areas and impact probabilities on different seas were studied for each case. It was shown that about 70% sand-dust storms that influenced China originally came from Mongolia, and were strengthened during their movement in the desert areas of China. There were totally 42 sand-dust storms influencing China and three movement routes from west to east during 2000-2002. Firstly, sand-dust originally occurred in Mongolia intruded into China from the east part of Inner Mongolia, by the way of Hunshandake desert and Horqin desert, and were deposited into the Bohai sea, the Yellow sea, Korea Strait and Japan sea; secondly, sand-dust coming from Mongolia intruded into China from the west of Inner Mongolia, were transported from west to east, and then sunk into the Bohai sea, the Yellow sea, the East China sea, Korea Strait and Japan Sea; and thirdly, sand-dust that occurred in Mongolia and in the northwest of China were transported by the high northwest current and sunk into the Yellow sea, the East China sea and the West Pacific Ocean. There were about 63.9% sand dust weather that might affect China seas by the three different routes. The impact probability on the Bohai sea was 27.4%, the Yellow sea 30.9%, the East China sea 12.3%, Korea Channel 20.2% and Japan sea 9.2%.

To recuperate the shortage of soil moisture, based on hourly soil moisture date observed from April 2001 to June 2003 in western and central Inner Mongolia of China, the change regulation of daily mean soil moisture and daily mean wind speed and their integrative contributions are analyzed in the paper. Then rationality of the statistic result is discussed, from which some interesting results can be drawn as follows: (1）The minimum value of daily mean wind speed for dust storm emission is 3.5m/s, and dust storm will occur when the wind speed over 8m/s in this area. (2）There are 18.4% of dust storms that occurred and 81.6% of non-dust storms that occurred in the total data collected when the wind speed was more than 3.5m/s. It indicated that dynamical factor with daily mean wind speed is not a most important one in the factors of dust storm emission. (3）If only soil moisture and wind speed are consider, when there is a inverse relation between daily mean soil moisture and daily mean wind speed, dust storm would occurred (r= 0.674). Otherwise, if their relation were not shown as this inverse, dust storm would not occur. The formation and development of dust storm is an integrative result of soil moisture and wind speed. Continuous data of soil moisture would be an avail index to study dust storm for showing the humid status of soil directly and for scaling the status of vegetation cover indirectly.

Researching dust storm is very important for ecological environment construction and sustainable development in the north of China.In the past ten years, the dust storm weather in the north of China has shown an upward trend, and researchers in relating subjects began studying dust storm from different sides. This article summarizes the development of studying dust storm by remote sensing in the world. Firstly, this paper gives a brief review of the history and actuality about researching dust storm in the world, then, it systemically introduces the data resources, characteristics, theories and technologies about researching dust storm with remote sensing. Among which, we lay emphasis on the technologies of researching dust storm with remote sensing. Finally, aiming at the shortage of actual research, this paper conceives the development trend of studying dust storm using remote sensing in future:① Using multi-sources image data is the major trend in the dust storm research and establishing quantitative remote sensing model of information extraction is also important;② It is necessary to do some ground experiments in the proper area to improve the precise of calculation of dust storm optics thickness, sandy quantity and intensity; ③ It is also very important to extract some parameters(such as land use, moist of soil, composition and structure of vegetation) of ground data along dust storm path by remote sensing. In addition, based on GIS, it is urgent to establish the spatial database about Gobi, desert, desertification land and potential densification land, and combining the climatic factors (temperature, precipitation and wind) and topography conditions relating dust storm to develop quantitative model to analysis the relationship between ground surface factor and the intensity of dust storm.

An analysis on the relationship between percentage of coverage of vegetation and days of sandstorm in central and western Inner Mongolia autonomous region is performed in this paper, taking percentage of coverage of vegetation and days of sandstorm as indexes and using the NDVI data of NOAA/AVHRR and meteorological observation data from earth surface. The study shows that in this area :
(1) Positive anomaly of days of sandstorm matches with the negative anomaly of percentage of coverage of vegetation in 1980’s and negative anomaly of days of sandstorm matches with the positive anomaly of percentage of coverage of vegetation in 1990’s.
(2) There is a negative interrelation between the days of sandstorm and the percentage of coverage of vegetation, which varies due to the difference of geomorphic feature and the changes of season.
The negative interrelation between the percentage of coverage of vegetation in summer(July、August and September) in sand-covering area and the days of sandstorm in the next year is of the most markedness.

This article summarizes the field and progress about the research of dust storm. The methods of extracting dust storm information and dividing dust storm information by density based on (NOAA/AVHRR data is provided.  Compared with meteorological data, the result is satisfactory. By analysis the relationship between dust storm and surface (land cover and vegetables coverage degree)  in Northern China, it is proved that the land cover and vegetable coverage degree have more relationship with the form of dust storm and change of its intensity in same  meteorological conditions.

Mineral dust affects the radiation and energy budget of the earth mainly by absorbing and scattering solar and terrestrial radiation, and thus affects the climate change. It is generally stated that the net radiative effect of dust corresponds to a cooling effect at the surface and a warming at the altitude of the dust layers. But the sign of the effect of the mineral aerosol on the radiative budget at the surface and at-top-of-atmosphere depends on highly variable dust parameters, primarily the concentration, mineralogical composition, size distribution and vertical distribution of the particles, and on external parameters such as the surface albedo and temperature. Meanwhile, both climate change and human activities, such as land use, desertification and metropolitanization, could lead to the change of mineral dust in the atmosphere. It is now believed that mineral dust plays an important role in the global climatic and environmental change.

Dynamics and Engineering of Blown Sand and Sand Dunes, which studies natures and characteristics of fluid field of blown sand, boundary conditions, mechanics, processes and the relationl and forms, and engineering approaches to prevent the calamity of blown sand, is of a basic and (or) applied basical branch of science. The present and near future research focuses on three aspects: deepening under standing of blown sand phenomena, principle and measuers of blown sand calamity prevention and development of resources in desert. Based on the trends of studies in this field mentioned above, the author suggests that we should take the dynamical mechanics of blown sand, soil erosion by wind, processes of desertification, form and formation of Aeolian landforms, nature of Aeolian sedimentary deposits and their formation processes, dusts storm, engineering principle and approaches to prevent the calamity of blown sand etc.as main research tasks at present and near future.