Discriminate Analysis for Dust Storm Prediction in the Gobi and Steppe Regions in Mongolia

A discriminate analysis method for probability forecast of dust storms in Mongolia has been developed. The prediction method uses data recorded at 23 meteorological stations in the Gobi and steppe regions of Mongolia, including surface air pressure and geo-potential height at the 500-hPa level on grid points, and weather maps from 1975 to 1990. Weather elements such as air temperature, pressure, geo-potential height etc, which influence the formation of dust storms, are prepared as predictors. To select the most informative/important predictors (variables), we used a mean correlation matrix of variables together with the Mahalonobis distance, and correlation coefficients between dust storms and predictors with an orthogonalization for removing correlated predictors. The most informative predictors for dust storm prediction are intensities of surface cyclones and migratory anticyclones, passage of cold fronts, the horizontal gradients of the surface air pressure in the cold frontal zone, cyclonic circulations from the ground surface up to the 500-hPa level, the geo-potential height at 500-hPa level and its temporal changes. Selected predictors are used in discriminate analysis for formulating dust storm prediction equations. Sandstorm data have been classified into three classes, viz., strong, moderate and weak dust storms, depending on their intensities, durations and areas covered. Predictions of the probabilities of dust storm occurrence use the prediction equations for each class. The prediction is made from 12 hours to 36 hours. Verification of the probability forecasts of dust storms is also shown. The accuracy of forecasts is 72.2–79.9% with the data used for developing equations (dependent variables), in contrast to 67.1–72.0% with unrelated data for deriving equations (independent variables).     

Identification of PM10 Sources in a Mediterranean Island

Due to the dry Mediterranean climate in Cyprus, particulate matter is resuspended from soils and other surfaces. From November 2002 to August 2003, gravimetric PM₁₀ measurements were carried out at three characteristic sites (traffic, residential and rural). A significant seasonal trend with high winter concentrations was observed at the traffic site. Special events, e.g. long-range transport of Sahara dust storms, were recorded over traffic, residential and rural areas in the order of six to eight events per year, with a major frequency in summer and spring periods. This contributes to the increase of 24-h EU limit value exceedances for PM₁₀ at the three investigated sites. The origin of the PM₁₀ load was determined by enrichment factors based on analyses of the local soil deposition at the investigated sites. Furthermore, positive matrix factorisation modelling was applied to find the sources of PM₁₀. Results indicate that the major emission sources affecting the PM₁₀ load were mineral soil, sea salt, road dust, oil combustion, secondary pollutants and gasoline vehicles. The natural contribution (local mineral soil and sea salt) at the three sites was in the range of 7–9 μg m^?3 in PM₁₀. Besides the Sahara dust storms and natural background concentrations, the vehicular pollution was found as the largest contributor (12–14 μg m^?3) to PM₁₀ load at the traffic site.     

What Anthropogenic Radionuclides (90Sr and 137Cs in Atmospheric Deposition, Surface Soils and Aeolian Dusts Suggest for Dust Transport over Japan

Currently, atmospheric anthropogenic radionuclides (particulate) are controlled by suspension of the surface dust containing those radionuclides (resuspension). We have found, therefore, that such radionuclides can be used as tracers of the surface dust suspension, transport and its subsequent deposition in distant areas. The ¹³⁷Cs/⁹⁰Sr activity ratios in the atmospheric deposition, without the direct influence of nuclear tests and accidents, at the Meteorological Research Institute (MRI, Tsukuba, Japan) during the 1990s were fairly low (average: 2.1). This value is not in agreement with the ratios in Japanese surface soils (range of averages: 4–7), which had been considered as the primary source of the deposited dust. This suggests that the current atmospheric dust deposition in Japan is a mixture of local and remote components. The remote component could be an aeolian dust that has been transported long distances from arid areas. The major component is most likely to be Asian dust. It was further hypothesized that other remote source may exist beyond the Asian domain, based on accumulated observations and model results. To obtain more information about the dust transport, Sahara dust deposited in Monaco in 2002 and a suspended dust collected in the Taklamakan area in 2001 were analyzed for ⁹⁰Sr and ¹³⁷Cs. The Taklamakan dust exhibited a ¹³⁷Cs/⁹⁰Sr ratio of about 4, which is within the range of atmospheric deposition observed at the MRI, while the Sahara dust exhibited a higher ¹³⁷Cs/⁹⁰Sr ratio (about 13). Although the present Sahara datum was negative for our hypothesis of ‘hyper-range transport’, the seasonal change of the ¹³⁷Cs/⁹⁰Sr ratio in the atmospheric deposition observed at the MRI requires an aeolian dust source having a low ¹³⁷Cs/⁹⁰Sr ratio, other than Asian dust.     

Feature of Dust Particles in the Spring Free Troposphere over Dunhuang in Northwestern China: Electron Microscopic Experiments on Individual Particles Collected with a Balloon-borne Impactor

Free tropospheric aerosol particles were collected using a balloon-borne particle impactor in August of 2002 and March of 2003 at Dunhuang in northwestern China (40°00′N, 94°30′E), and the morphology and elemental composition of the aerosol particles were analyzed in order to understand the mixing state of coarse dust particles (diameter >1 μm) over the desert areas in the Asian continent in spring. Electron microscopic experiments on the particles revealed that dust particles were major constituents of coarse mode particles in the free troposphere over the Taklamakan Desert in spring and summer. Si-rich or Ca-rich particles are major components of dust particles collected in the free troposphere over dunhuang and the values of [number of Ca-rich particles]/[number of Si-rich particles] differs markedly between spring and summer, being about 0.3 in the spring of 2003 and about 1.0 in the summer of 2002 at heights 3–5 km above sea level. It is likely that the condition of the ground surface and the strength of vertical mixing in source areas of Asian dust are potential factors causing the difference in the chemical types of dust particles. Comparison of the elemental compositions of these particles with those of particles collected over Japan strongly suggests that these particles were chemically modified during their long-range transport in the free troposphere. Analysis of wind systems shows that both the predominating westerly wind in the free troposphere and the surface wind strongly controlled by the geographical structure of the Tarim Basin are important in the long-range transport of KOSA particles originating in the Taklamakan Desert.     

Aerosol Composition Change due to Dust Storm: Measurements between 1992 and 1999 at Gosan,Korea

Aerosol composition change between dust storm and non duststorm periods is studied using the TSP (Total SuspendedParticulate) data measured at Gosan, Korea between 1992 and1999. The concentrations of elements measured between 1993and 1996 and those of ions between 1992 and 1999 duringdust storms are compared with those during non-dust stormperiods in spring (March, April, and May). Among theanalyzed ions, the concentrations of crustal species(potassium, calcium, magnesium, and chloride) andanthropogenic species (nitrate and non-sea salt (nss)-sulfate) increased when dust storm occurs while those ofammonium and sodium did not increase. Among the analyzedelements, the concentrations of crustal species (Fe, Al,Ca, Ti, and Zn) increased when dust storm occurs whilethose of anthropogenic species (Mn, V, Ni, Cu, Cd, and Cr)did not increase. The only anthropogenic element of whichconcentration increased during dust storm periods was Pb.It was found that the concentrations of nitrate and nss-sulfatewere highest during spring. Also, the ratio of theyearly average concentrations of nitrate to nss-sulfateincreases, probably due to the emission trend change innortheast Asia, especially, in China.     

Study of Asian Dust Phenomena in 2001–2003 Using A Network of Continuously Operated Polarization Lidars

We have conducted dust observations at a number of locations including Beijing, Hefei, Suwon, Fukue, Nagasaki, Tsukuba, and Sapporo using automated two-wavelength polarization lidars o study Asian dust phenomena, including generation, transport, and change during transport. We developed a method using the depolarization ratio for estimating the contributions of Asian dust and spherical air-pollution aerosols in observed aerosol mixtures. We analyzed the dust profiles statistically to derive climatological characteristics and year-on-year variations. We also studied dust source and transport path for each dust event using the regional chemical transport model CFORS. The statistical analysis clearly demonstrated the year-on-year variation of dust phenomena and the characteristics depending on the locations of the observational sites. Most major dust events in 2001 and 2002 originated in Inner Mongolia and/or Mongolia at the southern edge of a low-pressure area located in Siberia and were transported by strong westerlies. In 2003, the typical meteorological pattern for heavy dust cases accompanying a strong low in Siberia was not seen, except for one case in April. Furthermore, the lidar observation in Beijing suggests that less dust was generated in the source regions in Inner Mongolia and/or Mongolia, probably due to higher precipitation in 2003.     

Investigation of Boundary Layer Fine Structure in Arid Regions: Injection of Fine Dust into the Atmosphere

Fine structure of the atmospheric boundary layerin desert regions of Kalmykia and on dried bottom of theAral Sea and its relation to soil particle emission in theatmosphere are discussed. It was found that in a hot seasonin the absence of dust storms convective processes lift updust particles into the atmospheric boundary layer fromsandy landscapes of Kalmykia and Sub-Aral regions. Thisaerosol consists of aggregate particles and contains asignificant amount of long-living aerosol of size less than5 m (including fine-dispersion 0.01–0.1 maerosol). The increasing of fine aerosol concentration wasfound at air temperature above 25 °C, surfacetemperature above 50 °C, and relative humidityless than 40–50%. Some mechanisms influencing the particle emission rates are briefly considered.     

Duststorms and Mesoscale Cloud Systems over The East Asian Deserts in Spring

Meteorological characteristics and morphology of duststorms and other dust weather phenomena in the arid regions of East Asia were described in order to investigate a possible role of mesoscale cloud disturbances that develop in synoptic-scale mid-latitude cyclones in intensifying dust weather. This study is a statistical examination of conventional surface observational data as well as satellite data obtained during April 2000–2003. In the deserts of Mongolia and northern China (e.g., the Gobi Desert) duststorms and other weaker dust weather (i.e., dust whirls, blowing dust) frequently occur under a strong influence of synoptic-scale cyclones; on the other hand in the Taklamakan Desert (northwestern China), dust weather phenomena occur in a less organized fashion and may be driven mainly by local meteorological and geographical effects. A significant signal was identified, revealing of the intensification of dust weather by the presence of convective cloud disturbances. Meteorological changes such as pressure rise and temperature drop, typically found during the passage of cold fronts, were frequently observed in the cases of duststorms occurring in the analysis region. However, no definite tendency was found for moisture change and wind speed in relation to cloud activity, probably because rainfall amount is generally too low to moisten the boundary-layer air.     

Anthropogenic Calcium Particles Observed in Beijing and Qingdao, China

Analysis of individual particles collected at Beijing in northern China revealed that particles abundant in calcium (Ca) always constituted a large fraction of mineral particles in the urban atmosphere. The particles were characterized by cubic morphologies. The major mineral element in the particles was Ca and few or no other mineral elements were detected. A large number of the particles were in the range of diameter <1 μm, where common natural mineral particles were rarely detected. The contribution of the Ca particles to the volume of total mineral particles greatly exceeded that of other mineral particles during non-dust-storm periods and was comparable to that during dust-storm periods. Reagent film tests showed that particulate sulfate and nitrate formation on the Ca particles was similar to that on common mineral particles. These results indicate that a large portion of Ca in the atmospheric particulate matter in Beijing was from anthropogenic sources rather than from natural sources, and the anthropogenic Ca particles acted as a significant medium for the formation of sulfate and nitrate. Similar particles were also detected at Qingdao, a coastal city in northern China. Data of a dust storm event showed that Ca-abundant particles from East China arrived there and moved out of the continent, similarly to Asian dust storm particles, suggesting possible contributions of anthropogenic Ca even in Asian dust storm samples in the downstream areas. Therefore, Ca may not be a good indicator of Asian dust from natural sources. However, the Ca particles, due to their unique shapes and elemental compositions, may provide an indicator for the atmospheric dispersion of anthropogenic particulate matters in East Asia.     

Characteristics of air pollution in Beijing during sand-dust storm periods

In the Beijing area, March and April have the highest frequency of sand-dust weather. Floating dust, blowing sand, and dust storms, primarily from Mongolia, account for 71%, 20%, and 9% of sand-dust weather, respectively. Ambient air monitoring and analysis of recent meteorological data from Beijing sand-dust storm periods revealed that PM₁₀ mass concentrations during dust storm events remained at 1500 μg m⁻³, which is five to ten times higher than during non-dust storm periods, for fourteen hours on both April 6 and 25, 2000. During the same period, the concentrations in urban areas were comparable to those in suburban areas, while the concentrations of gaseous pollutants, such as SO₂, NO _x , NO₂, and O₃, remained at low levels, owing to strong winds. Furthermore, during sand-dust storm periods, aerosols were created that consisted not only of many coarse particles, but also of a large quantity of fine particles. The PM_2.5 concentration was approximately 230 μg m⁻³, accounting for 28% of the total PM₁₀ mass concentration. Crustal elements accounted for 60–70% of the chemical composition of PM_2.5, and sulfate and nitrate for much less, unlike the chemical composition of PM_2.5 on pollution days, which was primarily composed of sulfates, nitrates, and organic material. Although the very large particle specific surface area provided by dust storms would normally be conducive to heterogeneous reactions, the conversion rate from SO₂ to SO₄ ²⁻ was very low, because the relative humidity, less than 30%, was not high enough.     

Long Range Transport of Asian Dust from Dust Storms and its Impact on Japan

We simulated the long range transport of dust emitted from dust storms that occurred in China by using a global three-dimensional chemical transport model. A modified dust emission flux scheme and a nonlocal diffusion scheme for determining the atmospheric eddy diffusivity in the atmospheric boundary layer were implemented to improve the chemical transport model. We examined the dust transport by comparing the model results with TOMS satellite images. The model calculated monthly total deposition of dust masses were used for comparison with the measurements collected at sampling stations in Japan, and good agreement was found. The model generally reproduced the temporal and spatial variations of dust reasonably well.     

The Relation Between Sandstorms and Strong Winds in Xinjiang,China

With observational data spanning 1961–1999 from 90 meteorological stations in Xinjiang, China, the spatial and temporal characteristics of sandstorms and strong winds, and the contribution of strong winds to the occurrence of sandstormsare analyzed. Moreover, the dominant wind direction and minimumwind speeds during sandstorm periods are discussed. The research shows that although possessing similar climatic trends, sandstorms and strong winds in Xinjiang have opposite geographical distributions, i.e. places with more sandstorms show fewer strong winds. The contribution of strongwinds to sandstorms in northern Xinjiang is larger than that insouthern Xinjiang. The dominant wind directions clearly indicatethe paths of the weather systems that introduced the sandstorms.The minimum wind speeds in the sandstorms were over 10 ms^-1in northern and eastern Xinjiang and in the Turpan and Yanqi Basins of southern Xinjiang. In Tarim Basin of southern Xinjiang,however, the minimum wind speed was about 6–8 ms^-1, and even 6 ms^-1 at its southern edge.     

Environmental Conditions of Dust Events in Northern China during 2000–2001

To investigate the large-scale environmental conditions of duststorms occurring in Northern China, a synoptic situation of tendust events in Northern China during 2000–2001 was composed andits dynamic features were identified. The composite synoptic situation showed that the occurrence of the ten dust events was associated with the eastward movement of a strong cold high fromMongolia, and the development of a cyclone in Northeast China, which caused the pressure gradient to intensify considerably in Northern China. The upper level circulation revealed that a 500 hPa trough developed rapidly above Northern China, and diagnosis showed that composite ascending motion was pronouncedabove the Siberian district. The change of vertical motion in themiddle and low troposphere above Mongolia was also related to theoccurrence of the ten dust events. When the descendingcurrent, 12 hr before the occurrence, was completely replacedby the ascending current, the instable atmospheric stratificationof the lower troposphere enabled dry dust to be transported from the surface to high altitudes toward Northern China.     

Local Circulation with Aeolian Dust on the Slopes and Foot Areas of the Tianshan and Kunlun Mountains around the Taklimakan Desert, China

Four automatic weather stations (AWS) were installed on the slopes and foot areas of the Tianshan and Kunlun Mountains along a longitude of 80 degrees east: (1) Taglak 2400 m a.s.l., (2) Aksu 1000 m, (3) Kartash 2800 m, and (4) Qira 1700 m. These two slopes face the Taklimakan Desert. Tagliak lies on the southern slope of Tianshan, and Kartash on the northern slope of Kunlun. The meteorological characteristics of the mountainous regions were investigated using surface data obtained during an intensive observation period (IOP) in spring 2002. It was found that visibility on the slopes decreases in the daytime, and there is no relationship between visibility and wind speed in the mountainous areas. Two snow layers containing dust particles were observed in the snow cover in Taglak during the IOP in spring 2003. These results suggest that a warm air parcel containing aeolian dust climbs over the slopes of the mountainous areas, and dust particles in the mountainous areas are transported from the foot areas.     

The Influence of Synoptic-scale Air Flow and Local Circulation on the Dust Layer Height in the North of the Taklimakan Desert

The present study investigates the influences of synoptic-scale air flows and local wind circulations on the dust layer height (DLH) in the Taklimakan Desert, based on lidar observations performed in the north of the desert in March 2003. The DLH fluctuates approximately every three days between 2500 m (above sea level) and 5000 m, including diurnal variations. Meteorological analyses and numerical simulations show that the three-day fluctuation of DLH corresponds with variations in synoptic-scale air flows over the Taklimakan Desert, and the diurnal variations are linked to downdrafts and updrafts that are formed over the north of the desert as part of local circulations. When strong northerly winds prevail in the upper troposphere and a developed valley wind blows toward the Tienshan Mountains in the lower troposphere, the downdrafts strengthen in the middle troposphere over the north of the desert, lowering the DLH to about 2500 m. In contrast, the DLH rises to about 5000 m when the updrafts develop between strong southerly winds in the upper troposphere and a developed mountain wind blowing from the Tienshan Mountains. Simulations for the local circulation behavior without the presence of the Tienshan Mountains demonstrate that the valley and mountain winds on the southern slope of the Tienshan Mountains control the intensity of the downdrafts and updrafts, thereby influencing the DLH over the north of the Taklimakan Desert.     

Current and future solid waste management system in Northern Viet Nam with focus on Ha Noi: climate change effects and landfill management

The contribution investigates the solid waste management system in Ha Noi under consideration of the interrelation between climate change effects and landfill management by means of a cause-and-effect-analysis as well as water balances using the HELP 3.95 model and gas emission data, followed by a Strength, Weakness, Opportunities, Threats (SWOT) analysis. Even landfills are sources of methane (CH₄) emissions they are also impacted by climate change. The main effects on landfill sites are the change of climatic conditions, namely the regional water balance, extreme precipitation and storm events. The results of the water balance model results show that a geomembrane surface sealing can reduce the leachate formation significantly, a fact that is also valid for the climate change scenario with higher precipitation. The risk of flooding and erosion at the landfill sites increases, which will require a customized water management. In parallel landfill gas offers the opportunity for recovery of Greenhouse Gases (GHG) and the generation of renewable energy. Some further management options are wind turbines, photovoltaic systems or biomass for biogas conversion, which was grown on closed landfill sites. The inclusion of climate friendly management options of closed landfills in a “Good Landfill Aftercare Practice” is recommended.     

Water Retention Capacity of Polysaccharides from Prickly Pear Nopals of <Emphasis Type="Italic">Opuntia Ficus Indica</Emphasis> and <Emphasis Type="Italic">Opuntia Litoralis</Emphasis>: Physical–Chemical Approach

Polysaccharides were isolated from nopals mucilage pulp and peel of Opuntia Ficus Indica (OFI) and Opuntia litoralis (OL) by aqueous extraction and purified by ultrafiltration. Studying the glycosyl residue composition, these polysaccharides were assumed to be rhamnogalacturonan I (RG-I). The macromolecular features of these compounds have been characterized by SEC/MALLS and by low shear viscosimetry. In the present work, we have undertaken a comparative study about different polysaccharides resulting from OFI and OL growing in different area. This comparison is to see the influence of the geographical area in which these two plants push on the mechanism of retention of water by the different polysaccharides extract. The polysaccharides resulting from the nopal peels of the two plants are highly methylated (>70%), thus they are much more hydrophobic especially for peels of OFI growing in the desert area than those resulting from pulps. Consequently, they probably prevent the evaporation of water in nopals by increasing their water retention capacity. Prickly pear nopals of OFI and OL contain a significant amount of water (>80%), carbohydrates (75% compared to the soluble matter), proteins (8% compared to the soluble matter) and salt (17% compared to the soluble matter). Thus, they represent an important source of water and alimentation especially in the arid and semi-arid areas.     

Soils, climate change and the OECD

Some concepts of sustainability applied to soils are given in relation to the Organisation for Economic Co-operation and Development (OECD) Co-operative Research Programme 'Biological Resource Management for Sustainable Agricultural Systems'. The application of these concepts to climate change will be discussed in relation to seven high-profile papers published over the past 12 months. It is argued that multi-disciplinary (including social science) approaches are needed to address the issues. There is also a brief discussion on biomass energy in terms of soil sustainability and climate change.     

The GaNE programme in a global perspective

This paper provides the background to this special issue, outlining the extent to which the global atmospheric nitrogen cycle has been modified by human activity and outlining the range of effects. The global total emissions of reduced and oxidized nitrogen, amount to 124 Tg N, and exceed those from natural sources (34 Tg N) by almost a factor of four showing the extent to which anthropogenic activity has taken over the global N cycle. Of the 124 Tg N, 70 Tg N is emitted in the oxidized form, largely as NO and 70% of which results directly from anthropogenic activity. The remaining 54 Tg N is emitted as NH₃, (66% anthropogenic). The enhanced nitrogen emissions are associated with a range of local, regional and global issues including, acidification, eutrophication, climate change, human health and tropospheric O₃. The paper also places the Global Nitrogen Enrichment (GaNE) research programme in the UK in a wider perspective.     

The GaNE programme in a global perspective

This paper provides the background to this special issue, outlining the extent to which the global atmospheric nitrogen cycle has been modified by human activity and outlining the range of effects. The global total emissions of reduced and oxidized nitrogen, amount to 124 Tg N, and exceed those from natural sources (34 Tg N) by almost a factor of four showing the extent to which anthropogenic activity has taken over the global N cycle. Of the 124 Tg N, 70 Tg N is emitted in the oxidized form, largely as NO and 70% of which results directly from anthropogenic activity. The remaining 54 Tg N is emitted as NH₃, (66% anthropogenic). The enhanced nitrogen emissions are associated with a range of local, regional and global issues including, acidification, eutrophication, climate change, human health and tropospheric O₃. The paper also places the Global Nitrogen Enrichment (GaNE) research programme in the UK in a wider perspective.