Investigations of planetary boundary layer processes and particle formation in the atmosphere of planet Mars

The planet Mars is the Earth's neighbour in the Solar System. Planetary research stems from a fundamental need to explore our surroundings, typical for mankind. Manned missions to Mars are already being planned, and understanding the environment to which the astronauts would be exposed is of utmost importance for a successful mission. Information of the Martian environment given by models is already now used in designing the landers and orbiters sent to the red planet. In particular, studies of the Martian atmosphere are crucial for instrument design, entry, descent and landing system design, landing site selection, and aerobraking calculations. Research of planetary atmospheres can also contribute to atmospheric studies of the Earth via model testing and development of parameterizations: even after decades of modeling the Earth's atmosphere, we are still far from perfect weather predictions. On a global level, Mars has also been experiencing climate change. The aerosol effect is one of the largest unknowns in the present terrestrial climate change studies, and the role of aerosol particles in any climate is fundamental: studies of climate variations on another planet can help us better understand our own global change. In this thesis I have used an atmospheric column model for Mars to study the behaviour of the lowest layer of the atmosphere, the planetary boundary layer (PBL), and I have developed nucleation (particle formation) models for Martian conditions. The models were also coupled to study, for example, fog formation in the PBL. The PBL is perhaps the most significant part of the atmosphere for landers and humans, since we live in it and experience its state, for example, as gusty winds, nightfrost, and fogs. However, PBL modelling in weather prediction models is still a difficult task. Mars hosts a variety of cloud types, mainly composed of water ice particles, but also CO2 ice clouds form in the very cold polar night and at high altitudes elsewhere. Nucleation is the first step in particle formation, and always includes a phase transition. Cloud crystals on Mars form from vapour to ice on ubiquitous, suspended dust particles. Clouds on Mars have a small radiative effect in the present climate, but it may have been more important in the past. This thesis represents an attempt to model the Martian atmosphere at the smallest scales with high resolution. The models used and developed during the course of the research are useful tools for developing and testing parameterizations for larger-scale models all the way up to global climate models, since the small-scale models can describe processes that in the large-scale models are reduced to subgrid (not explicitly resolved) scale.Planeettatutkimus versoo ihmiskunnalle tyypillisestä perustavanlaatuisesta tarpeesta tutkia ympäristöään. Mars on Maan naapuri Aurinkokunnassa ja ollut siten ihmisen eriasteisen mielenkiinnon kohteena jo vuosisatoja. Nykyään suunnitellaan jo miehitettyjä Mars-lentoja, joiden onnistumiseksi on äärimmäisen tärkeää ymmärtää ympäristöä, jolle astronautit planeetalla altistuisivat. Suunniteltaessa punaiselle planeetalle lähetettäviä laskeutujaluotaimia ja kiertolaisia käytetään hyväksi tietokonemallien antamaa tietoa Marsin ympäristöstä. Marsin ilmakehän tutkimuksesta on hyötyä erityisesti instrumenttien ja laskeutumisjärjestelmän suunnittelussa, laskeutumispaikan valinnassa ja ilmajarrutuslaskelmissa. Muiden planeettojen kaasukehien tutkimus voi edistää myös Maan ilmakehätutkimusta mallien testaamisen ja parametrisaatioiden kehittämisen kautta: vuosikymmenien ilmakehämallinnuskokemuksen jälkeen emme vieläkään pysty tuottamaan esimerkiksi tarkkoja sääennusteita. Ilmastonmuutosten tutkiminen toisella planeetalla voi auttaa meitä ymmärtämään oman planeettamme globaalia muutosta. Aerosolihiukkasten rooli missä tahansa ilmastossa on perustavanlaatuisen tärkeä, mutta niiden vaikutus on yksi suurimmista tuntemattomista tekijöistä Maan ilmastonmuutostutkimuksessa. Globaalissa mittakaavassa myös Mars on kokenut ilmaston muuttumisen, ja aerosolihiukkasten roolin tutkiminen sen kaasukehässä voi antaa arvokasta tietoa myös Maan ilmastonmuutostutkimukseen. Tässä väitöskirjassa tutkin kaasukehän alinta kerrosta, planetaarista rajakerrosta (PBL), käyttäen Marsin ilmakehää kuvaavaa pylväsmallia, minkä lisäksi kehitin myös nukleaatio- eli hiukkasmuodostusmalleja Marsin oloihin. Tutkimuksessani mallit myös yhdistettiin, jotta niiden avulla voitiin tutkia rajakerroksen sumun muodostumista. Rajakerros on kenties kaikkein merkittävin ilmakehän osa sekä laskeutujaluotaimille että ihmisille, koska elämme sen vaikutuksen alla ja koemme sen tilan esimerkiksi tuulen puuskaisuutena, yöpakkasina ja sumuina. Rajakerroksen mallintaminen säänennustusmalleissa on kuitenkin edelleen vaikea tehtävä. Toinen keskeinen tarkastelun kohde väitöskirjassani ovat Marsissa esiintyvät erityyppiset pilvet ja niiden syntyprosessi. Enemmistö Marsin pilvistä on muodostunut vesijäästä, mutta niiden lisäksi hyvin kylmässä napayössä ja muilla alueilla korkealla ilmakehässä muodostuu myös CO2-pilviä. Pilvikiteet muodostuvat höyrystä suoraan jääksi Marsin kaasukehässä leijuvien pölyhiukkasten päälle. Nukleaatio onkin hiukkasmuodostuksen ensiaskel ja siihen liittyy aina olomuodon muutos. Nykyilmastossa Marsin pilvillä on pieni vaikutus säteilynkulkuun, mutta niiden vaikutus on voinut olla suurempi menneisyydessä. Tämä väitöskirja esittelee Marsin kaasukehän pienimpien skaalojen ilmiöiden mallinnusta mahdollisimman tarkalla erotuskyvyllä ja tarkkuudella. Tutkimustyössä kehitetyt mallit soveltuvat työkaluiksi suuren (jopa pallonlaajuisen) skaalan malleihin tehtävien parametrisaatioiden kehittämiseen ja testaamiseen. Pienen skaalan mallit pystyvät kuvaamaan prosesseja, jotka laajan skaalan malleissa jäävät hilakokoa pienemmiksi eivätkä siis ole niissä suoraan ratkaistavissa

Global Climate Modeling of the Martian water cycle with improved microphysics and radiatively active water ice clouds

Radiative effects of water ice clouds have noteworthy consequences on the Martian atmosphere, its thermal structure and circulation. Accordingly, the inclusion of such effects in the LMD Mars Global Climate Model (GCM) greatly modifies the simulated Martian water cycle. The intent of this paper is to address the impact of radiatively active clouds on atmospheric water vapor and ice in the GCM and improve its representation. We propose a new enhanced modeling of the water cycle, consisting of detailed cloud microphysics with dynamic condensation nuclei and a better implementation of perennial surface water ice. This physical modeling is based on tunable parameters. This new version of the GCM is compared to the Thermal Emission Spectrometer observations of the water cycle. Satisfying results are reached for both vapor and cloud opacities. However, simulations yield a lack of water vapor in the tropics after Ls=180{\deg} which is persistent in simulations compared to observations, as a consequence of aphelion cloud radiative effects strengthening the Hadley cell. Every year, our GCM simulations indicate that permanent surface water ice on the north polar cap increases at latitudes higher than 80{\deg}N and decreases at lower latitudes. Supersaturation above the hygropause is predicted in line with SPICAM observations. The model also shows for the first time that the scavenging of dust by water ice clouds alone fails to fully account for observed dust detached layers.Comment: 19 pages, 13 figures, submitted to Journal of Geophysical Research (Planets

Rocket dust storms and detached dust layers in the Martian atmosphere

International audienceAirborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling that includes the transport of radiatively active dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, rather than by latent heating as in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30–50 km). Combined to horizontal transport by large-scale winds, rocket dust storms produce detached layers of dust reminiscent of those observed with Mars Global Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation is less efficient than daytime convective transport, and the detached dust layers can convect during the daytime, these layers can be stable for several days. The peak activity of rocket dust storms is expected in low-latitude regions at clear seasons (late northern winter to late northern summer), which accounts for the high-altitude tropical dust maxima unveiled by Mars Climate Sounder. Dust-driven deep convection has strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration

Analysis of high altitude clouds in the martian atmosphere based on Mars Climate Sounder observations

International Symposium on Sun, Earth, and Life, Jun 2016, Bandung, IndonesiaInternational audienceHigh altitude clouds have been observed in the Martian atmosphere. However, their properties still remain to be characterized. Mars Climate Sounder (MCS) aboard Mars Reconnaissance Orbiter (MRO) is an instrument that measures radiances in the thermal infrared, both in limb and nadir views. It allows us to retrieve vertical profiles of radiance, temperature and aerosols. Using the MCS data and radiative transfer model coupled with an automated inversion routine, we can investigate the chemical composition of the high altitude clouds. We will present the first results on the properties of the clouds. CO2 ice is the best candidate to be the main component of some high altitude clouds due to the most similar spectral variation compared to water ice or dust, in agreement with previous studies. Using cloud composition of contaminated CO2 ice (dust core surrounded by CO2 ice) might improve the fitting result, but further study is needed

An impedimetric study of DNA hybridization on paper-supported inkjet-printed gold electrodes

In this study, two different supramolecular recognition architectures for impedimetric detection of DNA hybridization have been formed on disposable paper-supported inkjet-printed gold electrodes. The gold electrodes were fabricated using a gold nanoparticle based ink. The first recognition architecture consists of subsequent layers of biotinylated self-assembly monolayer (SAM), streptavidin and biotinylated DNA probe. The other recognition architecture is constructed by immobilization of thiol-functionalized DNA probe (HSDNA) and subsequent backfill with 11mercapto1undecanol (MUOH) SAM. The binding capacity and selectivity of the recognition architectures were examined by surface plasmon resonance (SPR) measurements. SPR results showed that the HSDNA/MUOH system had a higher binding capacity for the complementary DNA target. Electrochemical impedance spectroscopy (EIS) measurements showed that the hybridization can be detected with impedimetric spectroscopy in picomol range for both systems. EIS signal indicated a good selectivity for both recognition architectures, whereas SPR showed very high unspecific binding for the HSDNA/MUOH system. The factors affecting the impedance signal were interpreted in terms of the complexity of the supramolecular architecture. The more complex architecture acts as a less ideal capacitive sensor and the impedance signal is dominated by the resistive elements

Mars Express science highlights and future plans

21st EGU General Assembly, EGU2019, proceedings from the conference held 7-12 April, 2019 in Vienna, Austria, id.11100After 15 years in orbit Mars Express remains one of ESA's most scientifically productive Solar System missions whose publication record now exceeds 1200 papers. Characterization of the geological processes on a local-to-regional scale by HRSC, OMEGA and partner experiments on NASA spacecraft has allowed constraining land-forming processes in space and time. Recent results suggest episodic geological activity as well as the presence of large bodies of liquid water in several provinces (e.g. Eridania Planum, Terra Chimeria) in the early and middle Amazonian epoch and formation of vast sedimentary plains north of the Hellas basin. Mars Express observations and experimental teams provided essential contribution to the selection of the Mars-2020 landing sites. Recent discovery of subglacial liquid water underneath the Southern polar cap has proven that the mission science potential is still not exhausted. More than a decade-long record of the atmospheric parameters such as temperature, dust loading, water vapor and ozone abundance, water ice and CO2 clouds distribution, collected by SPICAM, PFS, OMEGA, HRSC and VMC together with subsequent modeling have provided key contributions to our understanding of the martian climate. Recent spectroscopic monitoring of the 2018 dust storm revealed dust properties, their spatial and temporal variations and atmospheric circulation. More than 10,000 crossings of the bow shock by Mars Express allowed ASPERA-3 to characterize complex behavior of the magnetic boundary topology as function of the solar EUV flux. Observations of the ion escape during complete solar cycle revealed important dependencies of the atmospheric erosion rate on parameters of the solar wind and EUV flux and established global energy balance between the solar wind and escaping ion flow. The observations showed that ion escape can be responsible for removal of about 10 mbar over the Mars history that implies existence of other more effective escape channels. The structure of the ionosphere sounded by the MARSIS radar and the MaRS radio science experiment was found to be significantly affected by the solar activity, the crustal magnetic field, as well as by the influx of meteorite and cometary dust. MARSIS and ASPERA-3 observations suggest that the sunlit ionosphere over the regions with strong crustal fields is denser and extends to higher altitudes as compared to the regions with no crustal anomalies. Several models of the upper atmosphere and plasma environment are being developed based on and in support of the collected experimental data. The models aim at creating user-friendly data base of plasma parameters similar to the Mars Climate Database that would be of great service to the planetary community. A significant recent achievement was the flawless transition to the >gyroless> attitude control and operations mode on the spacecraft, that would allow mitigating the onboard gyros aging and extending the mission lifetime. In November 2018 ESA's Science Programme Committee (SPC) confirmed the mission operations till the end of 2020 and notionally approved its extension till the end of 2022. The talk will give the Mars Express status, review the recent science highlights, and outline future plans focusing on synergistic science with TGO

Investigations of the Mars Upper Atmosphere with ExoMars Trace Gas Orbiter

The Martian mesosphere and thermosphere, the region above about 60 km, is not the primary target of the ExoMars 2016 mission but its Trace Gas Orbiter (TGO) can explore it and address many interesting issues, either in-situ during the aerobraking period or remotely during the regular mission. In the aerobraking phase TGO peeks into thermospheric densities and temperatures, in a broad range of latitudes and during a long continuous period. TGO carries two instruments designed for the detection of trace species, NOMAD and ACS, which will use the solar occultation technique. Their regular sounding at the terminator up to very high altitudes in many different molecular bands will represent the first time that an extensive and precise dataset of densities and hopefully temperatures are obtained at those altitudes and local times on Mars. But there are additional capabilities in TGO for studying the upper atmosphere of Mars, and we review them briefly. Our simulations suggest that airglow emissions from the UV to the IR might be observed outside the terminator. If eventually confirmed from orbit, they would supply new information about atmospheric dynamics and variability. However, their optimal exploitation requires a special spacecraft pointing, currently not considered in the regular operations but feasible in our opinion. We discuss the synergy between the TGO instruments, specially the wide spectral range achieved by combining them. We also encourage coordinated operations with other Mars-observing missions capable of supplying simultaneous measurements of its upper atmosphere

No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations

The detection of methane on Mars has been interpreted as indicating that geochemical or biotic activities could persist on Mars today. A number of different measurements of methane show evidence of transient, locally elevated methane concentrations and seasonal variations in background methane concentrations. These measurements, however, are difficult to reconcile with our current understanding of the chemistry and physics of the Martian atmosphere, which-given methane's lifetime of several centuries-predicts an even, well mixed distribution of methane. Here we report highly sensitive measurements of the atmosphere of Mars in an attempt to detect methane, using the ACS and NOMAD instruments onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter from April to August 2018. We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections. We suggest that reconciliation between the present findings and the background methane concentrations found in the Gale crater would require an unknown process that can rapidly remove or sequester methane from the lower atmosphere before it spreads globally

Martian dust storm impact on atmospheric H₂O and D/H observed by ExoMars Trace Gas Orbiter

Global dust storms on Mars are rare but can affect the Martian atmosphere for several months. They can cause changes in atmospheric dynamics and inflation of the atmosphere, primarily owing to solar heating of the dust. In turn, changes in atmospheric dynamics can affect the distribution of atmospheric water vapour, with potential implications for the atmospheric photochemistry and climate on Mars. Recent observations of the water vapour abundance in the Martian atmosphere during dust storm conditions revealed a high-altitude increase in atmospheric water vapour that was more pronounced at high northern latitudes, as well as a decrease in the water column at low latitudes. Here we present concurrent, high-resolution measurements of dust, water and semiheavy water (HDO) at the onset of a global dust storm, obtained by the NOMAD and ACS instruments onboard the ExoMars Trace Gas Orbiter. We report the vertical distribution of the HDO/H O ratio (D/H) from the planetary boundary layer up to an altitude of 80 kilometres. Our findings suggest that before the onset of the dust storm, HDO abundances were reduced to levels below detectability at altitudes above 40 kilometres. This decrease in HDO coincided with the presence of water-ice clouds. During the storm, an increase in the abundance of H2O and HDO was observed at altitudes between 40 and 80 kilometres. We propose that these increased abundances may be the result of warmer temperatures during the dust storm causing stronger atmospheric circulation and preventing ice cloud formation, which may confine water vapour to lower altitudes through gravitational fall and subsequent sublimation of ice crystals. The observed changes in H2O and HDO abundance occurred within a few days during the development of the dust storm, suggesting a fast impact of dust storms on the Martian atmosphere

Sosiaalisen median markkinointiviestinnän kehittämissuunnitelma Panimo Kiiski Oy:lle

Tämän opinnäytetyön toimeksiantaja on mäntsäläläinen käsityöläispanimo Panimo Kiiski Oy, joka on perustettu vuonna 2016 ja aloittanut toimintansa vuonna 2017 kahden kaveruksen toimesta. Yrityksellä on käytössään sekä Facebook että Instagram sosiaalisen median markkinointia varten. Tämän opinnäytetyön tavoitteena oli kehittää Panimo Kiiski Oy:n sosiaalisen median markkinointia keskittyen jo olemassa olevien Facebook -ja Instagram-sivustojen markkinointiin. Tavoitteena oli luoda konkreettisia ehdotuksia sisällöntuotantoon kyselytutkimuksen avulla, jossa kerättiin vastauksia yrityksen Facebook -ja Instagram-markkinoinnin sisältöön liittyen pääosin mäntsäläläisiltä. Kyselytutkimus suoritettiin lokakuussa 2020 ja se oli auki viikon ajan (12.10.-19.10.2020). Linkki kyselyyn julkaistiin Panimo Kiiskin Instagram -ja Facebook-sivuilla, Mäntsälän Facebook-ryhmässä sekä kirjoittajan omalla Facebook-sivulla. Kyselytutkimuksen avulla selvitettiin esimerkiksi, millaista sisältöä kuluttajat haluaisivat nähdä ja millaista tietoa kuluttajat etsivät eri yrityksistä sosiaalisessa mediassa. Ideoita Panimo Kiiskin sosiaalisen median sisältöön kerättiin myös vertailuanalyysin avulla. Vertailuanalyysissa Panimo Kiiski Oy:n sosiaalisen median markkinointia verrattiin kahden suomalaisen pienpanimon, Maku Brewingin ja Malmgårdin Panimon sekä yhden ulkomaalaisen panimon, Founders Brewingin sosiaalisen median markkinointiin. Vertailuanalyysissa esiin nousseita ehdotuksia hyödynnettiin kyselytutkimuksen vastausvaihtoehdoissa. Lopputuloksena syntyi kehitysehdotuksia sosiaalisen median sisältöön liittyen yrityksen käyttöön tulevaisuuden markkinoinnissa. Isoimmat kehitysehdotukset päivitysten sisältöön ja teemoihin liittyen ovat luonto kuvausympäristönä, ruokasuositukset oluille ja reseptivinkit, joissa olutta voidaan hyödyntää, päivitykset kulissien takaa sekä kuvien hyvälaatuisuus ja sisällön julkaiseminen aina silloin, kun yrityksellä on asiaa