Search results for "OPOS"

Aircraft-based measurements of High Arctic springtime aerosol show evidence for vertically varying sources, transport and composition

2019

The sources, chemical transformations and removal mechanisms of aerosol transported to the Arctic are key factors that control Arctic aerosol–climate interactions. Our understanding of sources and processes is limited by a lack of vertically resolved observations in remote Arctic regions. We present vertically resolved observations of trace gases and aerosol composition in High Arctic springtime, made largely north of 80∘ N, during the NETCARE campaign. Trace gas gradients observed on these flights defined the polar dome as north of 66–68∘ 30′ N and below potential temperatures of 283.5–287.5 K. In the polar dome, we observe evidence for vertically varying source…

The airborne mass spectrometer AIMS – Part 1: AIMS-H<sub>2</sub>O for UTLS water vapor measurements

2016

Abstract. In the upper troposphere and lower stratosphere (UTLS), the accurate quantification of low water vapor concentrations has presented a significant measurement challenge. The instrumental uncertainties are passed on to estimates of H2O transport, cloud formation and the role of H2O in the UTLS energy budget and resulting effects on surface temperatures. To address the uncertainty in UTLS H2O determination, the airborne mass spectrometer AIMS-H2O, with in-flight calibration, has been developed for fast and accurate airborne water vapor measurements. We present a new setup to measure water vapor by direct ionization of ambient air. Air is sampled via a backward facing inlet that inclu…

Arctic black carbon during PAMARCMiP 2018 and previous aircraft experiments in spring

2021

Vertical profiles of the mass concentration of black carbon (BC) were measured at altitudes up to 5 km during the PAMARCMiP (Polar Airborne Measurements and Arctic Regional Climate Model simulation Project) aircraft-based field experiment conducted around the northern Greenland Sea (Fram Strait) during March and April 2018 from operation base Station Nord (81.6∘ N, 16.7∘ W). Median BC mass concentrations in individual altitude ranges were 7–18 ng m−3 at standard temperature and pressure at altitudes below 4.5 km. These concentrations were systematically lower than previous observations in the Arctic in spring, conducted by ARCTAS-A in 2008 and NETCARE in 2015, and similar to those observed …

The tropospheric processing of acidic gases and hydrogen sulphide in volcanic gas plumes as inferred from field and model investigations

2007

Abstract. Improving the constraints on the atmospheric fate and depletion rates of acidic compounds persistently emitted by non-erupting (quiescent) volcanoes is important for quantitatively predicting the environmental impact of volcanic gas plumes. Here, we present new experimental data coupled with modelling studies to investigate the chemical processing of acidic volcanogenic species during tropospheric dispersion. Diffusive tube samplers were deployed at Mount Etna, a very active open-conduit basaltic volcano in eastern Sicily, and Vulcano Island, a closed-conduit quiescent volcano in the Aeolian Islands (northern Sicily). Sulphur dioxide (SO2), hydrogen sulphide (H2S), hydrogen chlori…

Enhanced Tropospheric Wave Forcing of Two Anticyclones in the Prephase of the January 2009 Major Stratospheric Sudden Warming Event

2017

Monthly Weather Review, 145 (5)

Saharan dust absorption and refractive index from aircraft-based observations during SAMUM 2006

2009

During the Saharan Mineral Dust Experiment (SAMUM) conducted in summer 2006 in southeast Morocco, the complex refractive index of desert dust was determined from airborne measurements of particle size distributions and aerosol absorption coefficients at three different wavelengths in the blue (467 nm), green (530 nm) and red (660 nm) spectral regions. The vertical structure of the dust layers was analysed by an airborne high spectral resolution lidar (HSRL). The origin of the investigated dust layers was estimated from trajectory analyses, combined with Meteosat 2nd Generation (MSG) scenes and wind field data analyses. The real part n of the dust refractive index was found almost constant w…

The primary volcanic aerosol emission from Mt Etna: Size-resolved particles with SO2 and role in plume reactive halogen chemistry

2018

International audience; Volcanoes are an important source of aerosols to the troposphere. Within minutes after emission, volcanic plume aerosol catalyses conversion of co-emitted HBr, HCl into highly reactive halogens (e.g. BrO, OClO) through chemical cycles that cause substantial ozone depletion in the dispersing downwind plume.This study quantifies the sub-to-supramicron primary volcanic aerosol emission (0.2-5 μm diameter) and its role in this process. An in-situ ground-based study at Mt Etna (Italy) during passive degassing co-deployed an optical particle counter and Multi-Gas SO2 sensors at high time resolution (0.1 Hz) enabling to characterize the aerosol number, size-distribution and…

“Proposta di recupero e fruizione delle miniere di roccia asfaltica di Ragusa (Sicilia sud-orientale)-

2008

Osteonecrosis in Hodgkin lymphoma treated by BEACOPP

2018

Latvijas Vēstures Institūta Žurnāls. 2014, Nr. 2 (91)

2014

Valsts kultūrkapitāla fonds