Driving factors of aerosol properties over the foothills of central Himalayas based on 8.5 years continuous measurements

This study presents analysis of in situ measurements conducted over the period 2005–2014 in the Indian Himalayas to give a thorough overview of the factors and causes that drive aerosol properties. Aerosol extensive properties (namely, particle number concentration, scattering coefficient, equivalent black carbon, PM2.5, and PM10) have 1.5–2 times higher values in the early to late afternoon than during the night, and a strong seasonality. The interannual variability is ±20% for both PM2.5 and total particle number concentration. Analysis of the data shows statistically significant decreasing trends of −2.3 μg m−3 year−1 and −2.7 μg m−3 year−1 for PM2.5 and PM10, respectively, over the study period. The mountainous terrain site (Mukteshwar, MUK) is primarily under the influence of air from the plains. This is due to convective transport processes that are enhanced by local and mesoscale topography, leading to pronounced valley/mountain winds and consequently to atmospheric boundary layer air lifting from the plains below. The transport from plains is evident in seasonal‐diurnal patterns observed at MUK. The timing of the patterns corresponds with changes in turbulence and water vapor (q). According to our analysis, using these as proxies is a viable method for examining boundary layer influence in the absence of direct atmospheric boundary layer height measurements. Comparing the measurements with climate models shows that even regional climate models have problems capturing the orographic influence accurately at MUK, highlighting the importance of long‐term direct measurements at multiple points to understand aerosol behavior in mountainous areas

Secondary new particle formation in Northern Finland Pallas site between the years 2000 and 2010

Secondary new particle formation affects atmospheric aerosol and cloud droplet numbers and thereby, the aerosol effects on climate. In this paper, the frequency of nucleation events and the associated particle formation and growth rates, along with their seasonal variation, was analysed based on over ten years of aerosol measurements conducted at the Pallas GAW station in northern Finland. The long-term measurements also allowed a detailed examination of factors possibly favouring or suppressing particle formation. Effects of meteorological parameters and air mass properties as well as vapour sources and sinks for particle formation frequency and event parameters were inspected. In addition, the potential of secondary particle formation to increase the concentration of cloud condensation nuclei (CCN) sized particles was examined. Findings from these long-term measurements confirmed previous observations: event frequency peaked in spring and the highest growth rates were observed in summer, affiliated with increased biogenic activity. Events were almost exclusively observed in marine air masses on sunny cloud-free days. A low vapour sink by the background particle population as well as an elevated sulphuric acid concentration were found to favour particle formation. These were also conditions taking place most likely in marine air masses. Inter-annual trend showed a minimum in event frequency in 2003, when also the smallest annual median of growth rate was observed. This gives further evidence of the importance and sensitivity of particle formation for the condensing vapour concentrations at Pallas site. The particle formation was observed to increase CCN<sub>80</sub> (>80 nm particle number) concentrations especially in summer and autumn seasons when the growth rates were the highest. When the growing mode exceeded the selected 80 nm limit, on average in those cases, 211 ± 114% increase of CCN<sub>80</sub> concentrations was observed

Commercial Arctic shipping through the Northeast Passage:routes, resources, governance, technology, and infrastructure

The Russian and Norwegian Arctic are gaining notoriety as an alternative maritime route connecting the Atlantic and Pacific Oceans and as sources of natural resources. The renewed interest in the Northeast Passage or the Northern Sea Route is fueled by a recession of Arctic sea ice coupled with the discovery of new natural resources at a time when emerging and global markets are in growing demand for them. Driven by the expectation of potential future economic importance of the region, political interest and governance has been rapidly developing, mostly within the Arctic Council. However, this paper argues that optimism regarding the potential of Arctic routes as an alternative to the Suez Canal is overstated. The route involves many challenges: jurisdictional disputes create political uncertainties; shallow waters limit ship size; lack of modern deepwater ports and search and rescue (SAR) capabilities requires ships to have higher standards of autonomy and safety; harsh weather conditions and free-floating ice make navigation more difficult and schedules more variable; and more expensive ship construction and operation costs lessen the economic viability of the route. Technological advances and infrastructure investments may ameliorate navigational challenges, enabling increased shipping of natural resources from the Arctic to global markets.Albert Buixadé Farré, Scott R. Stephenson, Linling Chen, Michael Czub, Ying Dai, Denis Demchev, Yaroslav Efimov, Piotr Graczyk, Henrik Grythe, Kathrin Keil, Niku Kivekäs, Naresh Kumar, Nengye Liu, Igor Matelenok, Mari Myksvoll, Derek O'Leary, Julia Olsen, Sachin Pavithran.A.P., Edward Petersen, Andreas Raspotnik, Ivan Ryzhov, Jan Solski, Lingling Suo, Caroline Troein, Vilena Valeeva, Jaap van Rijckevorsel and Jonathan Wightin

Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300-2000 cm(-3) in the marine boundary layer and free troposphere (FT) and 1000-10 000 cm(-3) in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2-10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R-2=0.46) but fail to explain the observed seasonal cycle (R-2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=-88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=-25%). Simulated CN concentrations in the continental BL were also biased low (NMB=-74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R-2=0.3) than by increasing the number emission from primary anthropogenic sources (R-2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation-type nucleation parameterizations gave similar agreement with observed monthly mean CN concentrations

Musiikkikeskus Oulun keskustaan

Tiivistelmä. Kandidaatintyöni aiheena oli suunnitella musiikkikeskus Oulun keskustaan Pakkahuoneenkadulle. Halusin tehdä musiikkitalon, joka näkyy kaupunkikuvassa ja kutsuu muitakin kuin musiikin harrastajia musiikin maailmaan. Tavoitteena oli myös muodostaa uuden arkkitehtuurin avulla mielenkiintoista kaupunkitilaa Pakkahuoneenkadulle. Suunnittelutyölle varattu tontti sijaitsee tiiviissä korttelissa kahden rakennuksen välissä. Kaupunkikuvallisesti merkittävän musiikkitalon sijoittaminen tiiviiseen kaupunkirakenteeseen vaikutti aluksi haastavalta, mutta luonnosteluvaiheen ajatus rakennusmassan viemisestä Pakkahuoneenkadun yläpuolelle ratkaisi monia haasteita. Toisaalta ulokeratkaisun käyttö toi muita mielenkiintoisia suunnitteluhaasteita mukanaan. Yksi Nykyaikaisen arkkitehtuurin III-kurssin teemoista oli kiertotalouden ja kestävän kehityksen ratkaisujen toteuttaminen nykyarkkitehtuurin keinoja hyödyntämällä. Suunnittelutyön yhtenä tavoitteena oli hyödyntää tontilla olemassa olevaa rakennusta uudessa suunnitelmassa. Paikalla sijaitsee Veijo Kerolan suunnittelema konttori- ja liiketalo vuodelta 1962. Säilytin omassa suunnitelmassani vanhan rakennuksen betonisen pilarilaatta rungon kokonaisuudessaan ja lisäksi hyödynsin vanhan julkisivun kuparimateriaalia uudessa julkisivussa kollaasin muodossa. Rakennuksen uusi ja vanha osa ovat eri luonteiset, mutta yhteen sointuvat, molemmissa rakennuksen runkorakenteet ja -materiaalit ovat hallitsevia. Halusin jakaa rakennuksen toimintoja niin, että katutilaan kurottuvassa osassa on julkisemmat tilat ja vanhassa rakennuksen osassa on yksityisemmät tilat, eli esimerkiksi opetustilat ja toimistot. Toimintojen jakoa korostaa myös se, että kamarimusiikkisalista ja ravintolasta avautuu pitkä näkymä Pakkahuoneenkadulle, sekä opetus- ja toimistotiloista avautuu näkymä rauhalliselle sisäpihalle