Aerosol dynamics simulations on the connection of sulphuric acid and new particle formation

International audienceWe have performed a series of simulations with an aerosol dynamics box model to study the connection between new particle formation and sulphuric acid concentration. For nucleation either activation mechanism with a linear dependence on the sulphuric acid concentration or ternary H2O-H2SO4-NH3 nucleation was assumed. We investigated the factors that affect the sulphuric acid dependence during the early stages of particle growth, and tried to find conditions which would yield the linear dependence between the particle number concentration at 3?6 nm and sulphuric acid, as observed in field experiments. The simulations showed that the correlation with sulphuric acid may change during the growth from nucleation size to 3?6 nm size range, the main reason being the size dependent growth rate between 1 and 3 nm. In addition, the assumed size for the nucleated clusters had a crucial impact on the sulphuric acid dependence at 3 nm. The simulations yielded a linear dependence between the particle number concentration at 3 nm and sulphuric acid, when a low saturation vapour pressure for the condensable organic vapour was assumed, or when nucleation took place at ~2 nm instead of ~1 nm. Comparison of results with activation and ternary nucleation showed that ternary nucleation cannot explain the experimentally observed linear or square dependence on sulphuric acid

Keragaman Jenis Opisthobranchia di Taman Laut 17 Pulau Riung, Nusa Tenggara Timur

Penelitian inventarisasi jenis Opisthobranchia telah dilakukan untuk menunjang ekowisata di daerah Taman Laut 17 Pulau Riung. Taman laut ini terletak di kecamatan Riung, Kabupaten Ngada, Flores, Nusa Tenggara Timur. Kawasan ini di sebelah barat dibatasi oleh kabupaten Manggarai dan disebelah timur oleh desa Nggolonio, di utara dibatasi dengan laut Flores dan di selatan oleh Desa Wangka, Alo Mamek, dan Ten Terong. Areanya meliputi lima buah desa yaitu desa Lengkosambi, Tadho, Benteng Tengah, Nangamese dan Sambinasi. Secara geografis terletak antara 8o20’30” – 8o28’30” LS hingga 90o55’30” – 90o09’00” BT. Luas daratan sekitar 5 ha dan terumbu karang seluas 7.500 ha (Anonim a dan b. 1993). Opisthobranchia amat disukai oleh penyelam dan penggemar fotografi bawah laut dari mancanegara, namun masih amat sedikit penelitiannya di Indonesi

Large methane releases lead to strong aerosol forcing and reduced cloudiness

The release of vast quantities of methane into the atmosphere as a result of clathrate destabilization is a potential mechanism for rapid amplification of global warming. Previous studies have calculated the enhanced warming based mainly on the radiative effect of the methane itself, with smaller contributions from the associated carbon dioxide or ozone increases. Here, we study the effect of strongly elevated methane (CH4) levels on oxidant and aerosol particle concentrations using a combination of chemistry-transport and general circulation models. A 10-fold increase in methane concentrations is predicted to significantly decrease hydroxyl radical (OH) concentrations, while moderately increasing ozone (O3). These changes lead to a 70 % increase in the atmospheric lifetime of methane, and an 18 % decrease in global mean cloud droplet number concentrations (CDNC). The CDNC change causes a radiative forcing that is comparable in magnitude to the longwave radiative forcing ("enhanced greenhouse effect") of the added methane. Together, the indirect CH4-O3 and CH4-OH-aerosol forcings could more than double the warming effect of large methane increases. Our findings may help explain the anomalously large temperature changes associated with historic methane releases

A new feedback mechanism linking forests, aerosols, and climate

International audienceThe possible connections between the carbon balance of ecosystems and aerosol-cloud-climate interactions play a significant role in climate change studies. Carbon dioxide is a greenhouse gas, whereas the net effect of atmospheric aerosols is to cool the climate. Here, we investigated the connection between forest-atmosphere carbon exchange and aerosol dynamics in the continental boundary layer by means of multiannual data sets of particle formation and growth rates, of CO2 fluxes, and of monoterpene concentrations in a Scots pine forest in southern Finland. We suggest a new, interesting link and a potentially important feedback among forest ecosystem functioning, aerosols, and climate: Considering that globally increasing temperatures and CO2 fertilization are likely to lead to increased photosynthesis and forest growth, an increase in forest biomass would increase emissions of non-methane biogenic volatile organic compounds and thereby enhance organic aerosol production. This feedback mechanism couples the climate effect of CO2 with that of aerosols in a novel way

New insights into nocturnal nucleation

Formation of new aerosol particles by nucleation and growth is a significant source of aerosols in the atmosphere. New particle formation events usually take place during daytime, but in some locations they have been observed also at night. In the present study we have combined chamber experiments, quantum chemical calculations and aerosol dynamics models to study nocturnal new particle formation. All our approaches demonstrate, in a consistent manner, that the oxidation products of monoterpenes play an important role in nocturnal nucleation events. By varying the conditions in our chamber experiments, we were able to reproduce the very different types of nocturnal events observed earlier in the atmosphere. The exact strength, duration and shape of the events appears to be sensitive to the type and concentration of reacting monoterpenes, as well as the extent to which the monoterpenes are exposed to ozone and potentially other atmospheric oxidants

New particle formation in the Front Range of the Colorado Rocky Mountains

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei. Currently no conclusive evidence exists as to the mechanism or mechanisms of nucleation and subsequent particle growth. However, nucleation rates exhibit a clear dependence on ambient sulphuric acid concentrations and particle growth is often attributed to the condensation of organic vapours. A detailed study of new particle formation in the Front Range of the Colorado Rocky Mountains is presented here. Gas and particle measurement data for 32 days was analyzed to identify event days, possible event days, and non-event days. A detailed analysis of nucleation and growth is provided for four days on which new particle formation was clearly observed. Evidence for the role of sesquiterpenes in new particle formation is presented

Penguatan Kapasitas Pengelolaan BUMDes Di Desa Pariti, Kecamatan Sulamu Kabupaten Kupang-NTT

Badan Usaha Milik Desa (BUMDes) merupakan suatu badan usaha berbadan hukum, yang bertujuan untuk dapat meningkatkan perekonomian desa khususnya untuk peningkatan kesejahteraan masyarakat. Kegiatan penguatan kapasitas pengelolaan BUMDes dan sharing pengalaman pengelolaannya dalam kegiatan pengabdian pada masyarakat ini, bertujuan untuk dapat memberikan pengetahuan dan pengalaman baru bagi masyarakat. Kegiatan ini dilaksanakan di Desa Pariti, Kecamatan Sulamu, Kabupaten Kupang. Kegiatan ini diikuti oleh 20 oang peserta diantaranya Pemerintah Desa, pengurus BUMDes Gempar dan tokoh masyarakat. Metode pelaksanaan berupa sosialisasi melalui ceramah dan diskusi, sharing pengalaman dengan Kepala Desa Hadakewa serta hasil tes kemampuan (pre test dan post test). Kesimpulan dari hasil kegiatan ini yaitu terdapat peningkatan kemampuan terhadap substansi dan sistem tata kelola BUMDes. Kedepannya kegiatan ini dapat dilanjutkan dengan menghadirkan narasumber-narasumber yang telah sukses mengelola BUMDe

Politicians polarize and experts depolarize public support for COVID-19 management policies across countries

Significance Political polarization impeded public support for policies to address the spread of COVID-19, much as polarization hinders responses to other societal challenges. The present cross-country study demonstrates how the cues from political elites and affective polarization are analogous across countries addressing COVID-19. Far from being an outlier, the United States faces polarization challenges similar to those of other countries. Importantly, the results demonstrate that policies to combat public health crises are more supported when proposed by nonpartisan experts and bipartisan coalitions of political leaders. These results provide clear guidance on depolarizing communication strategies to improve global responses to health crises