Tropospheric water vapour observations by ground-based lidar

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Summary of lidar and star-photometer measurments in Ny-Alesund during the moon-photometer intercomparison campaign

star photometer and lidar measurements from Ny-Alesund in Feb. 2020 during the international moon photometer intercomparison campaign are presented

Measuring Energy Supply Risks: A G7 Ranking

The security of energy supply has again become a similarly hot topic as it was during the oil crises in the 1970s, not least due to the recent historical oil price peaks. In this paper, we analyze the energy security situation of the G7 countries using a statistical risk indicator and empirical energy data for the years 1978 through 2007.We find that Germany’s energy supply risk has risen substantially since the oil price crises of the 1970s, whereas France has managed to reduce its risk dramatically, most notably through the deployment of nuclear power plants. As a result of the legally stipulated nuclear phase-out, Germany’s supply risk can be expected to rise further and to approach the level of Italy.Due to its resource poverty, Italy has by far the highest energy supply risk among G7 countries.Herfindahl Index, Energy Supply Risk Indicator

Germany's Solar Cell Promotion: Dark Clouds on the Horizon

This article demonstrates that the large feed-in tariffs currently guaranteed for solar electricity in Germany constitute a subsidization regime that, if extended to 2020, threatens to reach a level comparable to that of German hard coal production, a notoriously outstanding example of misguided political intervention. Yet, as a consequence of the coexistence of the German Renewable Energy Sources Act (EEG) and theEUEmissions Trading Scheme (ETS), the increased use of renewable energy technologies does not imply any additional emission reductions beyond those already achieved by ETS alone. Similarly disappointing is the net employment balance, which is likely to be negative if one takes into account the opportunity cost of this form of solar photovoltaic support. Along the lines of the International Energy Agency (IEA 2007:77), we therefore recommend the immediate and drastic reduction of the magnitude of the feed-in tariffs granted for solar-based electricity. Ultimately, producing electricity on this basis is among the most expensive greenhouse gas abatement options.Energy policy, energy security, learning effects

Long-term decline of spring AOD in Ny-Alesund

The long-term decline of Arctic Haze, based on photometer measurments from AWIPEV is presented

Economic Impacts from the Promotion of Renewable Energy Technologies - The German Experience

The allure of an environmentally benign, abundant, and cost-effective energy source has led an increasing number of industrialized countries to back public financing of renewable energies. Germany's experience with renewable energy promotion is often cited as a model to be replicated elsewhere, being based on a combination of far-reaching energy and environmental laws that stretch back nearly two decades. This paper critically reviews the current centerpiece of this effort, the Renewable Energy Sources Act (EEG), focusing on its costs and the associated implications for job creation and climate protection. We argue that German renewable energy policy, and in particular the adopted feed-in tariff scheme, has failed to harness the market incentives needed to ensure a viable and cost-effective introduction of renewable energies into the country's energy portfolio. To the contrary, the government's support mechanisms have in many respects subverted these incentives, resulting in massive expenditures that show little long-term promise for stimulating the economy, protecting the environment, or increasing energy security.Energy policy, energy security, climate, employment

Lossless State Detection of Single Neutral Atoms

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 microseconds. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.Comment: 4 pages, 4 figure

The Nature of the Ny-Ålesund Wind Field Analysed by High-Resolution Windlidar Data

In this work we present windlidar data for the research village Ny-Ålesund located on Svalbard in the European Arctic (78.923°N, 11.928°E) from 2013 to 2021. The data have a resolution of 50 m and 10 min with an overlapping height of about 150 m. The maximum range depends on the meteorologic situation. Up to 1000 m altitude the data availability is better than 71%. We found that the highest wind speeds occur in November and December, the lowest ones in June and July, up to 500 m altitude the wind is channelled strongly in ESE to NW direction parallel to the fjord axis and the synoptic conditions above 1000 m altitude already dominate. While the fraction of windy days (v>10m/s) varies significantly from month to month, there is no overall trend of the wind visible in our data set. We define gusts and jets by the requirement of wind maxima v>2m/s above and below a wind maximum. In total, more than 24,000 of these events were identified (corresponding to 6% of the time), of which 223 lasted for at least 100 min (“Long Jets”). All of these events are fairly equally distributed over the months relatively to the available data. Further, gusts and jets follow different distributions (in terms of altitude or depths) and occur more frequently for synoptic flow from roughly a southerly direction. Jets do not show a clear correlation between occurrence and synoptic flow. Gusts and jets are not related to cloud cover. We conclude that the atmosphere from 400 m to 1000 m above Ny-Ålesund is dominated by a turbulent wind shear zone, which connects the micrometeorology in the atmospheric boundary layer (ABL) with the synoptic flow

Lidar-Derived Aerosol Properties from Ny-Ålesund, Svalbard during the MOSAiC Spring 2020

In this work, we present Raman lidar data (from a Nd:YAG operating at 355 nm, 532 nm and 1064 nm) from the international research village Ny-Ålesund for the time period of January to April 2020 during the Arctic haze season of the MOSAiC winter. We present values of the aerosol backscatter, the lidar ratio and the backscatter Ångström exponent, though the latter depends on wavelength. The aerosol polarization was generally below 2%, indicating mostly spherical particles. We observed that events with high backscatter and high lidar ratio did not coincide. In fact, the highest lidar ratios (LR > 75 sr at 532 nm) were already found by January and may have been caused by hygroscopic growth, rather than by advection of more continental aerosol. Further, we performed an inversion of the lidar data to retrieve a refractive index and a size distribution of the aerosol. Our results suggest that in the free troposphere (above ≈2500 m) the aerosol size distribution is quite constant in time, with dominance of small particles with a modal radius well below 100 nm. On the contrary, below ≈2000 m in altitude, we frequently found gradients in aerosol backscatter and even size distribution, sometimes in accordance with gradients of wind speed, humidity or elevated temperature inversions, as if the aerosol was strongly modified by vertical displacement in what we call the “mechanical boundary layer”. Finally, we present an indication that additional meteorological soundings during MOSAiC campaign did not necessarily improve the fidelity of air backtrajectories.Peer Reviewe