The Top 10 Improvements to the Version 4 Level 2 CALIPSO Lidar Data Products

No abstract availabl

Mg-Doped CuFeO₂ Photocathodes for Photoelectrochemical Reduction of Carbon Dioxide

Mg-doped CuFeO₂ delafossite is reported to be photoelectrochemically active for CO₂ reduction. The material was prepared via conventional solid-state methods, and subsequently assembled into an electrode as a pressed pellet. Addition of a Mg²⁺ dopant is found to substantially improve the conductivity of the material, with 0.05% Mg-doped CuFeO₂ electrodes displaying photocathodic currents under visible irradiation. Photocurrent is found to onset at irradiation wavelengths of ∼800 nm with the incident photon-to-current efficiency reaching a value of 14% at 340 nm using an applied electrode potential of −0.4 V vs SCE. Photoelectrodes were determined to have a −1.1 V vs SCE conduction band edge and were found capable of the reduction of CO₂ to formate at 400 mV of underpotential. The conversion efficiency is maximized at −0.9 V vs SCE, with H₂ production contributing as a considerable side reaction. These results highlight the potential to produce Mg-doped p-type metal oxide photocathodes with a band structure tuned to optimize CO₂ reduction

<i>p</i>‑Type CuRhO₂ as a Self-Healing Photoelectrode for Water Reduction under Visible Light

Polycrystalline CuRhO₂ is investigated as a photocathode for the splitting of water under visible irradiation. The band edge positions of this material straddle the water oxidation and reduction redox potentials. Thus, photogenerated conduction band electrons are sufficiently energetic to reduce water, while the associated valence band holes are energetically able to oxidize water to O₂. Under visible illumination, H₂ production is observed with ∼0.2 V underpotential in an air-saturated solution. In contrast, H₂ production in an Ar-saturated solution was found to be unstable. This instability is associated with the reduction of the semiconductor forming Cu(s). However, in the presence of air or O₂, bulk Cu(s) was not detected, implying that CuRhO₂ is self-healing when air is present. This property allows for the stable formation of H₂ with ca. 80% Faradaic efficiency

DUSEL-related Science at LBNL -- Program and Opportunities

The National Science Foundation is advancing the design of a Deep Underground Science and Engineering Laboratory (DUSEL) at the former Homestake mine in South Dakota. UC Berkeley and LBNL are leading the design effort for the facility and coordinating the definition and integration of the suite of experiments to be coupled to the facility design in the creation of an MREFC (Major Research Equipment and Facility Construction) proposal. The State of South Dakota has marshaled $120M to prepare the site and begin a modest science program at the 4850 ft level. The first physics experiment is anticipated to begin installation in 2009. The current timetable calls for the MREFC Preliminary Design to be assembled by 2010 to be presented to the National Science Board in 2011. This, in turn, indicates that the earliest DUSEL construction start would be FY2013. The MREFC is estimated (before the inclusion of the long baseline neutrino components) at$500--600M, roughly divided evenly between the experimental program and support for the facility. Construction was estimated at 6--8 years. The DOE and NSF are establishing a Joint Oversight Group (JOG) to coordinate the experimental programs and participation in DUSEL. It is anticipated that the JOG would mirror the similar function for the NSF and DOE participation in the LHC, and that DOE-HEP, DOE-NP, and NSF will all participate in the JOG. In parallel with the NSF efforts, DOE-HEP plans to develop a long baseline neutrino program with neutrino beams created at FNAL and aimed at DUSEL. In the P5 report the focus of the program is to pursue CP violation in the lepton sector. The same detectors can also be used for nucleon decay experiments. DOE has indicated that FNAL would be the ''lead lab'' for the long baseline neutrino program and be charged with designing and implementing the neutrino beamline. BNL is to be charged with designing and implementing the detector. The P5 report also emphasizes the importance of dark matter and neutrinoless double beta decay searches. The Nuclear Physics Long Range Plan strongly endorses DUSEL and the associated nuclear physics programs. It mentions, in particular, neutrinoless double beta decay, and accelerator-based nuclear astrophysics measurements as key elements of the DUSEL nuclear physics experimental program. There are numerous fundamental scientific questions that experiments which can naturally be sited at DUSEL can address. LBNL has a long tradition and track record of successful experiments in all of these areas: neutrino physics, dark matter searches, and nuclear astrophysics. Clearly, DUSEL presents many scientific opportunities, and the committee was charged to present a roadmap for LBNL participation, the impact that LBNL is likely to have on experiments at the present level of effort, the value of additional manpower, and opportunities for synergistic Detector R&amp;D activities. The Berkeley community is already deeply involved in a number of experiments and/or proposals, shown in Table 1, that will be relevant to science at DUSEL. The approximate time lines for all projects considered in this report are shown in Table 2. For the DUSEL-related experiments the depth at which they would be located is also shown. Section 2 of this report deals with nuclear astrophysics. Section 3 discusses neutrinoless double beta decays. Section 4 focuses on neutrino oscillations, including the search for CP violation and proton decay. Section 5 deals with dark matter searches. In each section we give a brief overview of that field, review the present Berkeley efforts, and discuss the opportunities going into the future. Section 6 contains our recommendations

Introducing CALIPSO’s Version 4 Level 2 Lidar Data Products

International audienceThe NASA-CNES CALIPSO mission released Version 4.1 (V4.1) of their lidar level 2 (LL2) data products in November 2016. This new release from uses significantly improved retrieval algorithms to provide increased accuracy and substantially reduced uncertainties in the derived parameters. Here we present a comprehensive overview of the V4.1 LL2 data products, and show examples illustrating the improvements made in retrieving the spatial distributions and optical properties of clouds and aerosols

p

Polycrystalline CuRhO2 is investigated as a photocathode for the splitting of water under visible irradiation. The band edge positions of this material straddle the water oxidation and reduction redox potentials. Thus, photogenerated conduction band electrons are sufficiently energetic to reduce water, while the associated valence band holes are energetically able to oxidize water to O2. Under visible illumination, H2 production is observed with ∼0.2 V underpotential in an air-saturated solution. In contrast, H2 production in an Ar-saturated solution was found to be unstable. This instability is associated with the reduction of the semiconductor forming Cu(s). However, in the presence of air or O2, bulk Cu(s) was not detected, implying that CuRhO2 is self-healing when air is present. This property allows for the stable formation of H2 with ca. 80% Faradaic efficiency