The cloud imaging and particle size experiment on the Aeronomy of Ice in the mesosphere mission: Instrument concept,design, calibration,and on-orbit performance

The Cloud Imaging and Particle Size Experiment (CIPS) is one of three instruments aboard the Aeronomy of Ice in the Mesosphere spacecraft. CIPS provides panoramic ultraviolet images of the atmosphere over a wide range of scattering angles in order to determine the presence of polar mesospheric clouds, measure their spatial morphology, and constrain the parameters of cloud particle size distribution. The AIM science objectives motivate the CIPS measurement approach and drive the instrument requirements and design, leading to a configuration of four wide-angle cameras arrayed in a ‘+’ arrangement that covers a 120° (along orbit track)×80° (across orbit track) field of view. CIPS began routine operations on May 24, 4 weeks after AIM was launched. It measures scattered radiances from PMCs near 83 km altitude to derive cloud morphology and particle size information by recording multiple exposures of individual clouds to derive PMC scattering phase functions and detect nadir horizontal spatial scales to approximately 3 km. This paper describes the instrument design, its prelaunch characterization and calibration, and flight operations. Flight observations and calibration activities confirm performance inferred during ground test, verifying that CIPS exceeds its measurement requirements and goals. These results are illustrated with example flight images that demonstrate the instrument measurement performance.     

Olivine intergranular plasticity at mantle pressures and temperatures

The ductile behavior of olivine-rich rocks is critical to constrain thermal convection in the Earth's upper mantle. Classical olivine flow laws for dislocation or diffusion creep fail to explain the fast post-seismic surface displacements observed by GPS, which requires a much weaker lithosphere than predicted by classical laws. Here we compare the plasticity of olivine aggregates deformed experimentally at mantle pressures and temperatures to that of single crystals and demonstrate that, depending on conditions of stress and temperature, strain accommodated through grain-to-grain interactions – here called intergranular strain – can be orders of magnitude larger than intracrystalline strain, which significantly weakens olivine strength. This result, extrapolated along mantle geotherms, suggests that intergranular plasticity could be dominant in most of the upper mantle. Consequently, the strength of olivine-rich aggregates in the upper mantle may be significantly lower than predicted by flow laws based on intracrystalline plasticity models.     

High-pressure yield strength of rocksalt structures using quartz Raman piezometry

The Raman frequencies of quartz are used to evaluate deviatoric stresses in rocksalt-structure media in diamond-anvil cell experiments to pressures up to 20 GPa. The piezospectroscopic effect in quartz is modeled by first-principles calculations. Non-hydrostatic stresses measured in halogen salts give yield strength estimates of 3 GPa in the B1 structure (NaCl), and 4.5 GPa for the B2 structure (KCl and KBr). Raman measurements in MgO show that the yield strength is reached at around 6 ± 1 GPa. Measurements on quartz alone indicate similar yield strength. The estimated yield strength in MgO is thus likely a lower bound, in consistency with former radial X-ray diffraction measurements that gave a yield strength of 8 ± 1 GPa, and lower-pressure large-volume press experiments indicating a yield strength of 6 GPa at 5 GPa. Former values of the yield strength below 2 GPa determined by pressure gradient measurements were underestimated due to unverified assumptions in boundary conditions. The yield strength increases with increasing coordination of ionic solids, likely contributing to increase viscosity at phase transitions near the upper–lower mantle boundary.     

Estimation of groundwater recharge using a GIS-based distributed water balance model in Dire Dawa, Ethiopia

Sustainable groundwater management requires knowledge of recharge. Recharge is also an important parameter in groundwater flow and transport models. Spatial variation in recharge due to distributed land-us.e, soil texture, topography, groundwater level, and hydrometeorological conditions should be accounted for in recharge estimation. However, conventional point-estimates of recharge are not easily extrapolated or regionalized. In this study, a spatially distributed water balance model WetSpass was used to simulate long-term average recharge using land-use, soil texture, topography, and hydrometeorological parameters in Dire Dawa, a semiarid region of Ethiopia. WetSpass is a physically based methodology for estimation of the long-term average spatial distribution of surface runoff, actual evapotranspiration, and groundwater recharge. The long-term temporal and spatial average annual rainfall of 626 mm was distributed as: surface runoff of 126 mm (20%), evapotranspiration of 468 mm (75%), and recharge of 28 mm (5%). This recharge corresponds to 817 l/s for the 920.12 km² study area, which is less than the often-assumed 1,000 l/s recharge for the Dire Dawa groundwater catchment.     

Application of Landsat 5 and Landsat 7 images data for water quality mapping in Mosul Dam Lake,Northern Iraq

Mosul Dam Lake is the main reservoir in Iraq, supporting the water demand of Mosul, Baghdad, and other cities. The aim of this study is to derive simple and accurate algorithms for the retrieval of water quality parameters for Mosul Dam Lake from Landsat 5 and Landsat 7 reflectance data. The water quality measurements were performed in situ during March and July 2011. These measurements included temperature, turbidity, Secchi disk, chlorophyll-a, nitrate, nitrite, phosphate, total inorganic carbon, dissolved organic carbon, total dissolved solids, and pH. In order to properly use the values of reflectance bands, images enhancement techniques have been used. The field measurements were compared with reflectance values of Landsat 5 and Landsat 7 bands using different band combination of empirical algorithms. Generally, the results of analysis showed significant correlation between these models and water quality parameters with R ²?>?0.7 and p?R ²?>?0.9 and p?R ²?>?0.9, and values of the root mean square error ranged from 0.9 to 0.001. ArcGIS 10 was used to simulate the distribution values of water quality parameters calculated from spectral values of TM5 and ETM+ bands. The results of spatial analysis demonstrate that it is possible to use the TM5 and ETM+ images to evaluate the water quality for Mosul Dam Lake.     

Effect of Microbial Siderophore DFOB on Pb, Zn, and Cd Sorption Onto Zeolite

Recent studies suggest that siderophores form stable complexes with divalent metals and affect their mobility. In this work, effects of trihydroxamate microbial siderophores and desferrioxamine-B (DFOB) on Pb(II), Zn(II), and Cd(II) sorption by two kinds of synthesized zeolites (13X and Na?CY) as a function of pH were investigated. Results showed that 13X zeolite has a higher sorption affinity for studied metals than Na?CY. DFOB strongly affected metal sorption on both zeolites. Under slightly acidic to neutral condition, DFOB increased the metal sorption on zeolites due to the sorption of positively charged heavy metal?CDFOB complexes. Whereas by increasing pH (>7), the mobilizing effect of DFOB was observed for Pb, Zn, and Cd. DFOB drastically decreased (80?%) Zn sorption in alkaline condition. As a result, siderophores can weaken the treatment efficiency of zeolites and increase the bioavailability of metals in soils. Surface complexation modeling revealed that the effects of DFOB on metal sorption by 13X and Na?CY zeolites can be explained by the differences in their surface charge. In general, the result shows the influence of DFOB on metal sorption by zeolites over the pH range 4?C9 and decreasing in the sequence Zn?>?Pb?>?Cd.     

Structural and mineralogical study of active and inactive hydrothermal fluid discharges in Panarea,Italy

The isle of Panarea (Aeolian Arc, Italy) is an active hydrothermal system, characterized by different types of fluid emissions, which cause various types of unique hydrothermal structures that are typical for hydrothermal fluid discharges. Such fluid discharge structures at shallow depths of less than 30 m have not been described in marine hydrothermal systems until now to the authors’ knowledge. The focus of the investigations was set on morphological, mineralogical, geochemical, and structural analyses. A broad variety of analytical methods was applied to gain as much information as possible. In addition to geological and sedimentological documentation and standard methods like making and analyzing thin and polished sections, optical microscopy or X-ray fluorescence analysis, the samples were investigated by X-ray computer tomography and scanning electron microscopy, including energy-dispersive X-ray spectroscopy. Because discharge features occur in various settings, a general classification of the features in the hydrothermal system was performed with special focus on their preservability in geological archives. In total, nine different facies types were distinguished based on genetic and/or morphological differences. All samples show laminated structures from µm to cm scale. The single laminae vary in shape and material witnessing various chemical compositions.     

The cloud imaging and particle size experiment on the aeronomy of ice in the mesosphere mission: Cloud morphology for the northern 2007 season

The Aeronomy of Ice in the Mesosphere (AIM) mission was launched from Vandenberg Air Force Base in California at 4:26:03 EDT on April 25, 2007, becoming the first satellite mission dedicated to the study of noctilucent clouds (NLCs), also known as polar mesospheric clouds (PMC) when viewed from space. We present the first results from one of the three instruments on board the satellite, the Cloud Imaging and Particle Size (CIPS) instrument. CIPS has produced detailed morphology of the Northern 2007 PMC and Southern 2007/2008 seasons with 5 km horizontal spatial resolution. CIPS, with its very large angular field of view, images cloud structures at multiple scattering angles within a narrow spectral bandpass centered at 265 nm. Spatial coverage is 100% above about 70° latitude, where camera views overlap from orbit to orbit, and terminates at about 82°. Spatial coverage decreases to about 50% at the lowest latitudes where data are collected (35°). Cloud structures have for the first time been mapped out over nearly the entire summertime polar region. These structures include ‘ice rings’, spatially small but bright clouds, and large regions (‘ice-free regions’) in the heart of the cloud season essentially devoid of ice particles. The ice rings bear a close resemblance to tropospheric convective outflow events, suggesting a point source of mesospheric convection. These rings (often circular arcs) are most likely Type IV NLC (‘whirls’ in the standard World Meteorological Organization (WMO) nomenclature).     

Impact of Alkaline Earth Metals on Aqueous Speciation of Uranium(VI) and Sorption on Quartz

The effect of Mg-, Ca-, and Sr–Uranyl-Carbonato complexes with respect to sorption on quartz was studied by means of batch experiments with U(VI) concentration of 0.126 × 10⁻⁶ M in the presence and absence of Mg, Ca, and Sr (each 1 mM) at pH from 6.5 to 9. In the absence of alkaline earth elements, 90% of the U(VI) sorbed on the quartz surface at all pH. In the presence of Mg, Ca, and Sr, the sorption of U(VI) on quartz decreased to 50, 10, and 30%, respectively. Sorption kinetics of U(VI) on quartz is faster in the absence of alkaline earth elements and reached equilibrium after 12 h, whereas in the presence of Mg, Ca and Sr, the kinetics of U(VI) sorption on quartz is pH dependent and attained equilibrium after 24 h. Aqueous speciation calculations for alkaline earth uranyl carbonates were carried out by using PHREEQC with the Nuclear Energy Agency thermodynamic database (NEA_2007) by adding constants for MUO₂(CO₃)₃²⁻ and M₂UO₂(CO₃)₃⁰ (M = Ca, Mg, Sr). This study reveals that alkaline earth elements can have a significant effect on the aqueous speciation of U(VI) under neutral to alkaline pH conditions and subsequently sorption behavior and mobility of U(VI) in aqueous environments.