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Gas emission strength and evolution of the molar ratio of BrO/SO2in the plume of Nyiragongo in comparison to Etna

2015

Airborne and ground-based differential optical absorption spectroscopy observations have been carried out at the volcano Nyiragongo (Democratic Republic of Congo) to measure SO2 and bromine monoxide (BrO) in the plume in March 2004 and June 2007, respectively. Additionally filter pack and multicomponent gas analyzer system (Multi-GAS) measurements were carried out in June 2007. Our measurements provide valuable information on the chemical composition of the volcanic plume emitted from the lava lake of Nyiragongo. The main interest of this study has been to investigate for the first time the bromine emission flux of Nyiragongo (a rift volcano) and the BrO formation in its volcanic plume. Mea…

Application of an O-ring pinch device as a constant-pressure inlet (CPI) for airborne sampling

2020

We present a novel and compact design of a constant-pressure inlet (CPI) developed for use in airborne aerosol mass spectrometry. In particular, the inlet system is optimized for aerodynamic lenses commonly used in aerosol mass spectrometers, in which efficient focusing of aerosol particles into a vacuum chamber requires a precisely controlled lens pressure, typically of a few hectopascals. The CPI device can also be used in condensation particle counters (CPCs), cloud condensation nucleus counters (CCNCs), and gas-phase sampling instruments across a wide range of altitudes and inlet pressures. The constant pressure is achieved by changing the inner diameter of a properly scaled O-ring that…

Summer Cooling Driven by Large Volcanic Eruptions over the Tibetan Plateau

2018

Large volcanic eruptions may cause abrupt summer cooling over large parts of the globe. However, no comparable imprint has been found on the Tibetan Plateau (TP). Here, we introduce a 400-yr-long temperature-sensitive network of 17 tree-ring maximum latewood density sites from the TP that demonstrates that the effects of tropical eruptions on the TP are generally greater than those of extratropical eruptions. Moreover, we found that large tropical eruptions accompanied by subsequent El Niño events caused less summer cooling than those that occurred without El Niño association. Superposed epoch analysis (SEA) based on 27 events, including 14 tropical eruptions and 13 extratropical eruptions,…

Accelerated Changes of Environmental Conditions on the Tibetan Plateau Caused by Climate Change

2011

Abstract Variations of land surface parameters over the Tibetan Plateau have great importance on local energy and water cycles, the Asian monsoon, and climate change studies. In this paper, the NOAA/NASA Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land (PAL) dataset is used to retrieve the land surface temperature (LST), the normalized difference vegetation index (NDVI), and albedo, from 1982 to 2000. Simultaneously, meteorological parameters and land surface heat fluxes are acquired from the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) dataset and the Global Land Data Assimilation System (GLDAS), respectively. Results show that from …

Spatial distribution of the precipitation in Dobruja (Romania/Black Sea)

2000

An original dataset for the Dobruja, a low plateau region of southeastern Romania, is used to perform a statistical study of the spatial distribution of rainfall at annual and seasonal time-scales. A principal component analysis (PCA) is carried out to identify the precipitation regimes. The high eigenvalue of PC1 attests of the prevailing temperate-continental regime, with a relatively dry winter opposed to a late spring and early summer rainfall maximum. PC2 shows the specific pattern of the coast, with a small secondary maximum in November. In spite of the relatively flat topography, annual rainfall is characterized by a strong gradient between the coast and the interior. Particularly lo…

Monitoring of Eyjafjallajökull volcanic aerosol by the new European Skynet Radiometers (ESR) network

2012

Abstract The passage of a volcanic plume produced by the eruption of Eyjafjallajokull volcano in April 2010 was measured by the sun–sky radiometers of the new European SkyRad (ESR) network. This network consists of several European sites located in the U.K., Poland, Spain and Italy, and therefore was particularly suitable for monitoring the transport of volcanic ash generated by this particular volcano. The atmospheric aerosol characteristics at each site affected by the passage of the volcanic cloud, during and after the eruption, have been reconstructed. For the U.K. ESR sites three events were identified by the sun–sky radiometers: the first, from April 15 to April 16 2010, related to th…

2009

Abstract. A characterization of the ultra-fine aerosol particle counter COPAS (COndensation PArticle counting System) for operation on board the Russian high altitude research aircraft M-55 Geophysika is presented. The COPAS instrument consists of an aerosol inlet and two dual-channel continuous flow Condensation Particle Counters (CPCs) operated with the chlorofluorocarbon FC-43. It operates at pressures between 400 and 50 hPa for aerosol detection in the particle diameter (dp) range from 6 nm up to 1 μm. The aerosol inlet, designed for the M-55, is characterized with respect to aspiration, transmission, and transport losses. The experimental characterization of counting efficiencies of th…

Spatial and temporal temperature trends on the Yunnan Plateau (Southwest China) during 1961-2004

2010

Monthly mean (TEM), maximum (Tmax) and minimum (Tmin) surface air temperatures at 119 meteorological stations on the Yunnan Plateau (YP, Southwest China) were analysed for temporal trends and spatial variation patterns during the period 1961–2004. Linear trend analyses revealed that annual temperature over the YP increased at a rate of 0.3 °C/decade during the period 1961–2004, while warming trend of 0.33 °C/decade and 0.26 °C/decade was observed for winter and summer temperatures, respectively. Warming trends of nighttime minimum temperature are more pronounced than those of daytime maximum temperature, especially during winter season. Consequently, a decreasing trend of diurnal temperatur…

Frequent ultrafine particle formation and growth in Canadian Arctic marine and coastal environments

2017

The source strength and capability of aerosol particles in the Arctic to act as cloud condensation nuclei have important implications for understanding the indirect aerosol–cloud effect within the polar climate system. It has been shown in several Arctic regions that ultrafine particle (UFP) formation and growth is a key contributor to aerosol number concentrations during the summer. This study uses aerosol number size distribution measurements from shipboard expeditions aboard the research icebreaker CCGS Amundsen in the summers of 2014 and 2016 throughout the Canadian Arctic to gain a deeper understanding of the drivers of UFP formation and growth within this marine boundary layer. UFP nu…

Temperature changes in the mid- and high- latitudes of the Southern Hemisphere

2012

A Hierarchical Ascending Classification is used to regionalize monthly temperature anomalies measured at 24 weather stations in Antarctica and the Sub-Antarctic and mid-latitude southern islands from 1973 to 2002. Three principal regions are identified that are geographically coherent: Eastern Antarctica, the Antarctic Peninsula and the Sub-Antarctic and mid-latitude islands. Within each region, consistent trends are observed: namely, stationary temperatures in ‘East-Antarctica’; a robust warming in the ‘Sub-Antarctic and mid-latitude islands’, most pronounced in austral summer (nearly 0.5 °C per decade); and a strong but more recent warming in the ‘Antarctic Peninsula’. Austral summer temp…