Arid Regions Of Asia Research Articles

Size-segregated compositional analysis of aerosol particles collected in the European Arctic during the ACCACIA campaign

Abstract. Single-particle compositional analysis of filter samples collected on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft is presented for six flights during the springtime Aerosol–Cloud Coupling and Climate Interactions in the Arctic (ACCACIA) campaign (March–April 2013). Scanning electron microscopy was utilised to derive size-segregated particle compositions and size distributions, and these were compared to corresponding data from wing-mounted optical particle counters. Reasonable agreement between the calculated number size distributions was found. Significant variability in composition was observed, with differing external and internal mixing identified, between air mass trajectory cases based on HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) analyses. Dominant particle classes were silicate-based dusts and sea salts, with particles notably rich in K and Ca detected in one case. Source regions varied from the Arctic Ocean and Greenland through to northern Russia and the European continent. Good agreement between the back trajectories was mirrored by comparable compositional trends between samples. Silicate dusts were identified in all cases, and the elemental composition of the dust was consistent for all samples except one. It is hypothesised that long-range, high-altitude transport was primarily responsible for this dust, with likely sources including the Asian arid regions.

Phosphate concentration and arbuscular mycorrhizal colonisation influence the growth, yield and expression of twelve PHT1 family phosphate transporters in foxtail millet (Setaria italica).

Phosphorus (P) is an essential element which plays several key roles in all living organisms. Setaria italica (foxtail millet) is a model species for panacoid grasses including several millet species widely grown in arid regions of Asia and Africa, and for the bioenergy crop switchgrass. The growth responses of S. italica to different levels of inorganic phosphate (Pi) and to colonisation with the arbuscular mycorrhizal fungus Funneliformis mosseae (syn. Glomus mosseae) were studied. Phosphate is taken up from the environment by the PHT1 family of plant phosphate transporters, which have been well characterized in several plant species. Bioinformatic analysis identified 12 members of the PHT1 gene family (SiPHT1;1-1;12) in S. italica, and RT and qPCR analysis showed that most of these transporters displayed specific expression patterns with respect to tissue, phosphate status and arbuscular mycorrhizal colonisation. SiPHT1;2 was found to be expressed in all tissues and in all growth conditions tested. In contrast, expression of SiPHT1;4 was induced in roots after 15 days growth in hydroponic medium of low Pi concentration. Expression of SiPHT1;8 and SiPHT1;9 in roots was selectively induced by colonisation with F. mosseae. SiPHT1;3 and SiPHT1;4 were found to be predominantly expressed in leaf and root tissues respectively. Several other transporters were expressed in shoots and leaves during growth in low Pi concentrations. This study will form the basis for the further characterization of these transporters, with the long term goal of improving the phosphate use efficiency of foxtail millet.

Phenolics, Antioxidant and Pasting Properties of Various Pearl Millet and Finger Millet varieties Varying in Amylose Content

Pearl millet and fingermillet are micronutrient rich staple foods for millions in arid regions of Asia and Africa. India being the largest producer of these millets, extruded products based on these can ensure both food and economic security amongst the malnutrition prone areas. Of the total phenols in pearlmillet (720–874 mg GAE/100g), approximately 40% of the phenols were present in the free form. While in fingermillet, total phenols ranged from 326–743.8 mg GAE/100 g, with approximately 48% in the free form. Positive correlations were found between phenols and antioxidant activity of millets through CUPRAC assay (p=0.00) and FRAP assay (p=0.005). The effect of starch composition in terms of amylose level on the pasting properties of four pearl millet varieties and ten fingermillet varieties was analysed and correlated to their X ray diffraction pattern. Amylose content showed a negative correlation to the percentage crystallinity, while it showed positive correlation to the pasting temperature (p< 0.05). X ray diffraction was found to give more accurate correlation to the pasting properties compared to amylose especially for fingermillet varieties. Percentage crystallinity had a negative correlation to the pea viscosity, holding strength, breakdown viscosity, final viscosity and setback from peak. The findings of this study formidate the effect of amylose content in raw material on the cooking attributes flours and shall prove to be a useful tool for industrial product development and design from the pearl millet and fingermillet sources.

Satellite-based assessment of large-scale land cover change in Asian arid regions in the period of 2001–2009

Arid regions in Asia are commonly characterized by rapidly growing populations with limited land resources and varying rainfall frequencies under climatic change. Despite being one of the most important environmental challenges in Asia, the changing aridity in this region, particularly due to large-scale land cover change, has not been well documented. In this study, we used rainfall data and a new land heterogeneity index to identify recent trend in land cover changes in the Asian arid regions. The result indicates a significant decreasing trend of barren lands and an increasing trend of vegetated lands. Although the potential land cover change is commonly believed to be strongly sensitive to rainfall change, such sensitivity has not been observed during the nine-year period (2001–2009) analyzed. Through the analyses of two separate periods (2001–2005 and 2005–2009), the sensitivity of rainfall to land cover change in arid regions is found to be dependent on the initial spatial heterogeneity of vegetated land cover. The approach used and the findings in this study represent an important step toward better understanding of large-scale land cover change in the Asian arid regions, and have the potential to predict future land cover change under various climate change scenarios.

Magnetic properties of coastal loess on the Midao islands, northern China: Implications for provenance and weathering intensity

Loess deposits are widely distributed over the islands in the Bohai Gulf and neighboring regions of northern China. The coastal loess, located to the east of the Chinese Loess Plateau (CLP), is believed to have a local source from exposed marine sediments and a distant source from inner arid regions in Asia. In this study, magnetic, geochemical and diffuse reflectance spectroscopic analyses were conducted on the loess to explore its relationship with the loess on the CLP and its paleoclimatic implications. We find that the coastal loess shows similar geochemical composition, background susceptibility and magnetic enhancement to loess on the CLP. Magnetic minerals characteristic of pedogenesis are more important in the paleosol layer, with fine ferrimagnetic minerals abundant in paleosol layer SB1 and hematite in paleosol layer SB2. Geochemical evidence suggests that weathering intensity in paleosol SB2 is similar to or even stronger than in paleosol SB1. Pedogenic enhancement of magnetic susceptibility in the study area is not so strong, which may be due to enhanced hematite formation as opposed to ferrimagnetic mineral production and preservation.

New Infrageneric Taxa of Corispermum L. (Chenopodiaceae)

Two new infrageneric taxa of Coris- permum L. (Chenopodiaceae) are described: sections Patellisperma and Declinata. Geographical distri- butions and taxonomic comments are provided. Corispermum L. (Chenopodiaceae, Corisper- meae) is a relatively compact and clearly defined genus consisting of ca. 60 almost obligately psam- mophytic species distributed primarily in the arid regions of Asia, with some species also native to temperate Europe, northern Asia, and North Amer- ica. Unfortunately, with the exception of three series described by Klokov (1960) in his monograph of some East European species, no infrageneric system has been proposed for this genus. The present paper may be regarded as the pre- liminary outline of the infrageneric classification of Corispermum (at the sectional level), since the prop- er placement of many insufficiently known species (e.g., sometimes represented in herbaria only by type collections) is not completely clear and remains a task for further study. It is especially true for Central and East Asian species (see Iljin, 1929; Tsien Cho- po & Ma Cheng-gung, 1979).

Origin of calcium in aerosols over the western North Pacific

Weekly aerosol samples were collected from March 1981 to June 1983 at the six stations in the western North Pacific region and analyzed for Ca and Na. By coupling data with those previously reported for Al (Tsunogai et al., 1985), the following results and conclusion have been obtained. There was a positive correlation between the atmospheric concentration of Al and the concentration of nonsea salt Ca (nssCa). The nssCa/Al ratios from the six stations, however, considerably varied (from 0.84±0.36 to 3.00±1.91), and the ratios were usally larger than those of the crustal average or of usual soil in Japan. The Ca/Al ratios of Asian desert soil and loess vary from 0.52 to 1.29, which are similar to the nssCa/Al ratios of aerosols in the surface air over the western North Pacific region except at Onna, Okinawa. The exception may be due to a local effect of coral. These results suggest that a large part of nonsea salt Ca in the surface air over the western North Pacific is derived from arid regions in Asia and that the nssCa/Al ratio in aerosol varies with that of the source material.

Deposition of atmospheric mineral particles in the North Pacific Ocean

Total deposition of atmospheric mineral particles (wet plus dry) has been measured during consecutive two-week sampling intervals from January, 1981 to March, 1982 at four island stations (Midway, Oahu, Enewetak, and Fanning) of the SEAREX Asian Dust Study Network in the North Pacific. The total deposition of mineral aerosol during the period from February to June is higher than that during the period from July to January at most of the stations. A systematic geographical trend is apparent in the dust flux, with greater fluxes at higher latitudes. The deposition values are correlated with the atmospheric mineral particle concentrations at these stations. The mineral particles are transported from arid regions in Asia to the North Pacific, and the annual dust deposition to the ocean appears to be dominated by sporadic dust events of short duration. Wet deposition dominates the removal of dust particles from the atmosphere over the North Pacific. The total deposition of atmospheric mineral material to the central North Pacific is estimated to be ∼20×1012 g yr-1.

Transport of mineral aerosol from Asia Over the North Pacific Ocean

Concentrations of atmospheric aluminum—a good indicator of mineral aerosol—have been measured weekly, between January 1981 and March 1982, at the seven stations of the SEAREX Asian Dust Network in the North Pacific. A seasonal transport pattern was found at most of the sites, with high Al concentrations from February to June and low concentrations from July to January. There was a latitudinal gradient in the mean annual atmospheric dust concentration, with the greatest concentrations occurring in the mid‐latitudes. When coupled with statistics of dust storms in Asia and of Kosa (dense dust hazes traced to Chinese origins) in Japan, the data suggest that the dust collected in the network was transported by the westerlies from arid regions in Asia. It is estimated that 6–12×106 tons of Asian dust are transported annually to the central North Pacific; larger quantities are probably deposited over the western North Pacific, closer to the Asian sources. This atmospherically transported mineral aerosol is a significant source of sedimentary material for the North Pacific.

Earth-atmosphere system and surface reflectivities in arid regions from LANDSAT MSS data

Previously developed programs for computing atmospheric transmission and scattering of the solar radiation are used to compute the ratios of the Earth-atmosphere system (space) directional reflectivities in the nadir direction to the surface Lambertian reflectivity, for the four bands of the Landsat multispectral scanner (MSS). These ratios are presented as graphs for two water vapor levels, as a function of the surface reflectivity, for various sun elevation angles. Space directional reflectivities in the vertical direction are reported for selected arid regions in Asia, Africa and Central America from the spectral radiance levels measured by the Landsat MSS. From these space reflectivities, surface reflectivities are computed applying the pertinent graphs. These surface reflectivities are used to estimate the surface albedo for the entire solar spectrum. The estimated albedos are in the range 0.34–0.52, higher than the values reported by most previous researchers from space measurements, but are consistent with laboratory and in situ measurements.

The Legal Problems of Reclamation of Lands By Means of Irrigation

Although irrigation, as applied to the individual dealing with his land, is new to the Anglo-Saxon race, it must have been an early form of agriculture. The earliest traces of civilization are in the arid region of Asia, where men found that, except in a few favored localities, it was impossible to raise crops without applying water to the land. Accordingly, we find in Asia evidences of irrigation work done at an early period and involving great labor and some degree of engineering skill. In Egypt, likewise, there are indications of massive work requiring an enormous amount of labor and the transportation of great quantities of material for long distances. The earliest records contain references to irrigation and the laws of the remotest times of which we have knowledge allude to irrigation matters and regulate various features of irrigation practice. The Anglo-Saxon race first encountered the subject of irrigation from an administrative standpoint in India; and the enormous development of irrigation works in recent years in that country is a monument to the energy of the British nation. So also in Egypt the British Government has taken hold of the irrigation question and has added wonderfully to the possibilities of development in that country. In Europe irrigation was introduced in the early stages of civilization, and when the discoverers reached the continent of America they found evidences that irrigation had been practiced for many generations. In the southwestern part of the United States there are ruins of ancient irrigation works and some of their sites are being used for the modern construction carried on under the auspices of the United States Reclamation Service. The gold miners of California were early confronted with the problem of determining the right to the use of water, because the gold mining involved the large use of streams of water under heavy pressure to break down the hillsides and carry the dirt away into (664)