Saturday, 27 December 2014

Mars Express radio-occultation data: A novel analysis approach

A bit less than two months after its submission, my first paper was accepted for publication in the Journal of Geophysical Research – Space Physics. The reference is:

Grandin, M, P.-L. Blelly, O. Witasse and A. Marchaudon, (2014), Mars Express radio-occultation data: A novel analysis approach, J. Geophys. Res. Space Physics, 119, doi:10.1002/2014JA020698.

The early-access version can be found here.

Abstract:
The Mars Express Radio Science (MaRS) experiment on board Mars Express has been providing radio-occultation data since early 2004. The analysis method currently used to retrieve neutral atmosphere and ionosphere profiles is based on the resolution of a complex inverse problem. The solution to such a problem is obtained under strong assumptions on the atmosphere and the ionosphere and with some limitations. Here we developed a novel method for radio-occultation data analysis based on a direct approach which overcomes some of the difficulties related to the standard inversion. This new method is based on a numerical model of the atmosphere and the ionosphere of Mars computing the propagation of the radio waves from the spacecraft to the receiver on Earth. The main interest of such an approach lies in the intrinsic and coherent coupling between the neutral part and the ionized part of the planetary environment, which gives physical constrains on the retrieved profiles. We have applied this new method to radio occultation experiments performed by MaRS, and we present the results obtained in two different occultation configurations. We discuss the differences which emerge from the standard analysis and the gain that such a method can give to the analysis of planetary environments.


Wednesday, 24 December 2014

Joululukemista: Jaakko Keränen - Suomen Sääprofessori

Heikki Nevanlinna on kirjoittanut kirjan Sodankylän geofysiikan observatorion ensimmäisestä johtajasta Jaakko Keräsestä (1883-1979). Hän tuli koko kansalle paremmin tunnetuksi Ilmatieteen laitoksen johtajana, aikansa mediahahmona "Sää-Keräsenä" ja "Suomen Sääprofessorina".

Ystävällisesti joulupukki toimitti kovakantisen version minulle. Sähköinen versio pdf:nä löytyy täältä: https://helda.helsinki.fi/handle/10138/144225. Eli jos sadan vuoden takainen observatoriomaailma ja Ilmatieteen laitoksen historia kiinnostaa, niin tässä varsin mielenkiintoista joululukemista. Kirjan on kustantanut Ilmatieteen laitos ja Sodankylän geofysiikan observatorio.

Ilmatieteen laitoksen uutinen kirjasta löytyypi täältä: http://ilmatieteenlaitos.fi/ajankohtaista/35939224. Tässä alla kyseisestä Ilmatieteen laitoksen tiedotteesta lainattu pätkä:

Jaakko Keränen

Jaakko Keränen oli kotoisin Kainuun Paltamosta maanviljelijäperheestä. Keränen nimitettiin silloisen Ilmatieteellisen keskuslaitoksen magneetikoksi vuonna 1911. Sääosaston johtajaksi hänet valittiin vuonna 1921. Sitä ennen hän oli tehnyt mittavan työn Suomalaisen Tiedeakatemian Sodankylän magneettisen observatorion ensimmäisenä johtajana 1913–1918. Keräsen tehtäviin kuului myös Suomen alueellinen magneettinen kartoitustyö, joka valmistui 1930-luvun alussa. Kyseessä oli osa suuresta kansainvälisestä maapallonlaajuisesta tutkimusohjelmasta. Sodankylästä Keränen siirtyi kolmeksi vuodeksi geodeettiseen laitokseen, missä hän osallistui Suomen ja Neuvostoliiton välisen Tarton rauhansopimuksen (1920) mukaisiin rajanmääritysmittauksiin Lapissa.
Tasavallan presidentti nimitti Keräsen Ilmatieteellisen keskuslaitoksen johtajaksi vuonna 1933. Ilmatieteellisen keskuslaitoksen johtajan tehtävistä Keränen siirtyi eläkkeelle vuonna 1953, mutta hän jatkoi meteorologian ja geofysiikan tiedeyhteisöissä eri tehtävissä vielä 1960-luvulle saakka. Jaakko Keräsen yli 20 vuotta kestäneen johtajakauden aikana Ilmatieteellisen keskuslaitoksen tehtäväalue laajeni merkittävästi ja henkilökunnan määrä kasvoi lähes kymmenkertaiseksi.

Lentoliikenteen alku 1920-luvulla toi laitokselle uusia ilmailumeteorologisia tehtäviä. Yleisradiotoiminnan käynnistyminen avasi laitokselle uusia mahdollisuuksia meteorologisten tietojen välitykseen. Jaakko Keränen tulikin tunnetuksi kansalaisille radion ja myös sanomalehtikirjoitusten kautta ilmatieteen symbolina ja mediahahmona, "Sää-Keräsenä" ja "Suomen Sääprofessorina".
Jatkosodassa 1941–1944 Keränen johti Ilmatieteellisen keskuslaitoksen toimintaa osana Puolustusvoimien koko maan kattavaa sääpalvelua.
Sodan jälkeen Jaakko Keränen vaikutti merkittävästi Sodankylän magneettisen observatorion uudelleenrakentamiseen. Observatorio tuhoutui täysin Lapin sodassa 1944. Keränen oli myös keskeinen henkilö, kun Ilmatieteellisen keskuslaitoksen Sodankylän aerologinen observatorio perustettiin vuonna 1949. Hänen johtajakautensa lopulla käynnistyi myös Nurmijärven magneettinen observatorio.
Jaakko Keränen oli aktiivisesti mukana Suomalaisessa Tiedeakatemiassa, jonne hänet valittiin vuonna 1926. Hänelle myönnettiin Suomalaisen Tiedeakatemian kunniapalkinto vuonna 1962. Keräsen tieteellinen tuotanto käsittää noin 170 julkaisua, jotka liittyvät lähinnä geomagneettisiin ja meteorologisiin aiheisiin.


Tuesday, 23 December 2014

Christmas is coming ... Kilpisjärvi/KAIRA power failure

We had a bit nervous day with KAIRA operations. KAIRA went silent around 10-11 am (LT). We learned  that this was due to a power line failure ~20 km north of Kaaresuvanto. The reason was a broken power line. Some other structures had failed also. Apparently in that region there has been freezing rain and heavy snowfall. Hence, frost in the power lines and the power failure. Here’s the news in Finnish about the Kilpisjärvi/KAIRA power failure: http://www.iltasanomat.fi/kotimaa/art-1419313726115.html


Finnish Meteorological Institute's Kilpisjärvi observations.
KAIRA came back online a bit after 20:00 LT. Hence, we are rather happy that we do not need to drive up to Kilpisjärvi for maintenance operations in Christmas Eve. It has been really cold in Kilpisjärvi during the last days. Temperature has dropped down to around -30 C. Despite of the ~10 hour power break. KAIRA survived and the operational temperature was 8.30 C when KAIRA came back online.
KAIRA operational temperature
at ~20:20 LT.

One interesting news: 2016 there will be a new 45 kV power transmission line. The current 20 kV line will serve as a back-up line thereafter. Hence, looking forward to an upgraded power service in the near future!

... and Merry Christmas!!




Thursday, 18 December 2014

Observatory Days 2015 - Programme

We have drafted the programme for the Observatory Days 2015. You may find the programme below. The event shall take place in Sodankylä Geophysical Observatory 7th-9th January 2015. All the talks will be in the Polaria lecture hall. The event website is here. Please note that if there will be further changes in the programme, the updated version will be only in the event website!

Monday, 8 December 2014

Observatory Days 2015 and Finnish EISCAT Collaboration Meeting


The Observatory Days 2015 shall be at Sodankylä Geophysical Observatory 7-9 January 2015. This is the final announcement. If you wish to participate, please send an email to lassi.roininen'at'sgo.fi (preferably as soon as possible). If you wish to talk, please send also your talk title.  The event will run all the way from Wednesday midday till Friday midday. The event website is at http://www.sgo.fi/~thu/SodankylaSeminars/index2015.php.

The next Finnish EISCAT Collaboration Meeting will be part of the Observatory Days and take place on Friday, 9th January 2015, in the morning.


There shall be no fee, but the lunches and coffees will be organised via prepaid coupons sold by our canteen that you can purchase when you arrive. 


Welcome to Sodankylä!



Friday, 5 December 2014

Plasma parameter estimation from multistatic, multibeam incoherent scatter data

We report that our latest study on multistatic, multibeam ISR, i.e. using EISCAT VHF incoherent scatter radar in conjunction with KAIRA receiver, has been accepted for publication in Journal of Geophysical Research - Space Physics. The paper is available as an early access version here. The reference is:

I. I. Virtanen, D. McKay-Bukowski, J. Vierinen, A. Aikio, R. Fallows and L. Roininen, Plasma parameter estimation from multistatic, multibeam incoherent scatter data, Journal of Geophysical Research, DOI:10.1002/2014JA020540.

Abstract:


Multistatic incoherent scatter radars are superior to monostatic facilities in the sense that multistatic systems can measure plasma parameters from multiple directions in volumes limited by beam dimensions and measurement range resolution. We propose a new incoherent scatter analysis technique that uses data from all receiver beams of a multistatic, multi-beam radar system and produces, in addition to the plasma parameters typically measured with monostatic radars, estimates of ion velocity vectors and ion temperature anisotropies. Because the total scattered energy collected with remote receivers of a modern multistatic, multibeam radar system may even exceed the energy collected with the core transmit-and-receive site, the remote data improves the accuracy of all plasma parameter estimates, including those that could be measured with the core site alone. We apply the new multistatic analysis method for data measured by the tristatic EISCAT VHF radar and the KAIRA multibeam receiver and show that a significant improvement in accuracy is obtained by adding KAIRA data in the multistatic analysis. We also demonstrate the development of a pronounced ion temperature anisotropy during high-speed ionospheric plasma flows in substorm conditions. 

Figure 1 from the Virtanen et al. paper showing some of the results obtained.

Thursday, 4 December 2014

Broadband Meter-Wavelength Observations of Ionospheric Scintillation

This week, the first KAIRA paper detailing the ionospheric scintillation observations we've been performing, and the "scintillation arc" phenomenon we've noted in the KAIRA blog (http://kaira.sgo.fi/2014/07/ionospheric-scintillation-arcs.html) was accepted for publication in the Journal of Geophysical Research.  The image shown is of a poster presented at the recent European Space Weather Week which summarises this work, along with a few more recent results taken with LOFAR.  The abstract of the paper follows and the full work can already be found online (http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014JA020406/).


Intensity scintillations of cosmic radio sources are used to study astrophysical plasmas like the ionosphere, the solar wind, and the interstellar medium. Normally these observations are relatively narrow band. With Low Frequency Array (LOFAR) technology at the Kilpisjarvi Atmospheric Imaging Receiver Array (KAIRA) station in northern Finland we have observed scintillations over a 3 octave bandwidth. “Parabolic arcs”, which were discovered in interstellar scintillations of pulsars, can provide precise estimates of the distance and velocity of the scattering plasma. Here we report the first observations of such arcs in the ionosphere and the first broad-band observations of arcs anywhere, raising hopes that study of the phenomenon may similarly improve the analysis of ionospheric scintillations. These observations were made of the strong natural radio source Cygnus-A and covered the entire 30-250 MHz band of KAIRA. Well-defined parabolic arcs were seen early in the observations, before transit, and disappeared after transit although scintillations continued to be obvious during the entire observation. We show that this can be attributed to the structure of Cygnus-A. Initial results from modeling these scintillation arcs are consistent with simultaneous ionospheric soundings taken with other instruments, and indicate that scattering is most likely to be associated more with the topside ionosphere than the F-region peak altitude. Further modeling and possible extension to interferometric observations, using international LOFAR stations, are discussed.

Monday, 1 December 2014

SGO's Advent Calendar

Today is the first day of Advent. It is also our first day in SGO without Iina Sirviö, who completed her bachelor thesis last Friday and therefore moved back to Jyväskylä for her studies.

But before leaving, as she knows that chocolate is generally a good remedy against yearning, she offered a nice Advent calendar to all of us.


SHARE THE CHOCOLATES

Now, all we need to do is find a fair way to share the chocolates equally, taking into account each one's trips and holidays.

Kiitos, Iina, ja nähdään pian!

Friday, 28 November 2014

Visit of the Centre Spatial de Liège

Last week, the 11th European Space Weather Week was organised in Liège and gathered together more than 400 scientists and engineers working on developing and improving the forecast of geomagnetic disturbances due to the solar activity.

On Monday morning, a visit of CSL (Centre Spatial de Liège) was organised, mixing presentations about the past, ongoing and planned projects in which CSL is involved and a visit of the test facilities – one of the four ESA testing centres.



The test centre has had very renowned guests, such as Planck and Herschel (the probes), the SWAP instrument (Sun Watcher using Active Pixel System Detector and Image processing) or the Heliospheric Imager instrument of the STEREO satellites.

The thermal box to perform the thermal testing of the probes/instruments

Different kinds of testing can be performed at CSL: thermal vacuum testing, mechanical testing and even cryogenic tests. 

The testing facilities verify class 10,000 norms (i.e. less than 10,000 particules per cubic foot), and if needed an inner chamber can be cleaned down to class 100. This is why the visitors of the test centre need to wear overshoes, lab coats and caps to enter the cleanroom.

One of the shakers to perform the vibrational tests

At CSL, for instance, the HI instrument of STEREO underwent the thermal vacuum and vibrational testings, while Herschel was brought to CSL for its cryo vibrational qualification. Perhaps the most impressive test which has been performed at CSL so far is the one consisting in maintaining the cold point of Planck at about 0.1 K for two weeks. During summer 2008, the coldest point of the known universe was certainly in Liège...

The chamber in which Planck was locked during its testing at CSL

This visit was extremely thrilling and it was great to hear of the technological feats which can be achieved in such facilities. Looking forward to seeing what new ambitious missions will be designed, assembled and tested there in the coming years!

Thursday, 27 November 2014

Norway spiral revisited!

On December 9, 2009, I was in the right place at the wrong time, i.e., about to start my radar experiment at the EISCAT control room.  People started to call me repeatedly "how did you do that?!"

Did what?

Photo: Jan-Petter Jørgensen

A huge spiral shaped light phenomenon had appeared in the eastern sky of Tromsø, clearly visible to a naked eye.

Holy s***t! Is that a distant galaxy seen through a worm hole or what?!

The event lasted for a few minutes and people were able to take photos and even video footage on it, posted promptly to the YouTube among other media. 

Since this was observed mainly in Tromsø, some people thought it was an EISCAT experiment. They found my name & contact info from the EISCAT website --- and started to email me. A lot. If you google "Antti Kero + spiral", you might find some quite dodgy conspiracy websites...

It turned out, however, that the spiral didn't actually take place in Norway at all, but above Kola Peninsula, Russia. The spiral itself was caused by exhaust gasses of a failed Russian "Bulava" test missile precessing like a garden hose. The gas trail was illuminated by the sunrise, making the spiral nicely visible against the dawn skies of Northern Norway. 

According to a recent paper by Alexander Kozlovsky (SGO) et al., the Bulava explosion fragments were, in fact, detected by SGO ionosonde and meteor radar ~2 hours later, please have a look:

SGO ionosonde (a-b) and meteor radar (c-f) data showing ionospheric effects of the missile explosion. Vertical dashed lines indicate time of the explosion occurred 500 km to east. 


Kozlovsky reports: "The Russian military Bulava missile is a three-stage solid propellant 36-tonnes ballistic rocket. On December 9, 2009 a test launch was performed from a submarine located in the White Sea. Because of a technical problem with the second stage, the missile was self-destroyed near 200 km altitude over the Kola Peninsula (north-west of Russia) soon after the launch. It happened at about 07 UT, which corresponds to sunrise. Illuminated by the Sun the combustion products of the fragments of the rocket formed a spiral, which was observed on the dawn sky in northern Norway."


Wednesday, 19 November 2014

EISCAT campaign 2014!




Mainland radar team at the Tromsø control room: Milla Anttila (DLR), Johannes Norberg (FMI) and Antti Kero (SGO). Daniel Whiter (FMI) carries out the experiments at the ESR, Svalbard.

Along this week, we have the annual Finnish EISCAT radar measurement campaign. You can follow the schedule (Finnish experiments denoted as "FI") and the real-time data analysis on-line. Today we conducted a simultaneous space-weather measurement with 22 Finnish High School students visiting the Arecibo radar in --- ayayayayayaaaaaaaa--- Puerto Rico!

Tuesday, 18 November 2014

Bahir Dar visit 2014 ... concluding remarks

I flew back to Finland in the weekend and now back at SGO office. On the contrary to the lush Bahir Dar, in Sodankylä it's winter and 'Grey17'. However, fortunately no slush :) !

Altogether, it was four weeks at the physics and math departments of Bahir Dar University. In addition, before travelling to BDU, I was one week at La Sapienza in Rome, Italy. So, five weeks abroad.

The BC/BDU coherent backscatter radar build
To conclude the science and education done at BDU: We have the BDU riometer running. We did give a series of lectures with Antti. We had good progress in our paper writing sessions with the local people. Hence, quite a nice visit. In addition, it was good to see the Boston College and Bahir Dar University coherent backscatter radar construction. Supposedly, we can also run some of our own tests with this radar, but this has to be further discussed with radar owners. As the radar has a solid-state transmitter, we should be able to run perfect-coded experiments. For the theory of perfect-coding techniques, see our series of papers in Inverse Problems and Imaging:
  1. M. Lehtinen, B. Damtie, P. Piiroinen and M. OrispääPerfect and almost perfect pulse compression codes for range spread radar targets, Inverse Problems and Imaging, 3 465-486 (2009).
  2. L. Roininen and M. Lehtinen, Perfect pulse-compression coding via ARMA algorithms and unimodular transfer functions, Inverse Problems and Imaging, 7 649-661 (2013).
  3. L. Roininen, M. Lehtinen, P. Piiroinen and I. VirtanenPerfect Radar Pulse Compression via Unimodular Fourier Multipliers, Inverse Problems and Imaging, 8 831-844 (2014).
Thank you for all the folks at BDU and hope to come back soon again :) !!

... and here we feature some photos of the BC/BDU radar construction!

Radar under construction!
Here's the 16 kW solid-state amp + receiver system
And here's the antenna field on Friday... Still under construction!

Saturday, 15 November 2014

Tähtimittaaja Uula taivasmatkalla

Enpä voinut aavistaa untuvikkona luonnontieteiden ylioppilaana Sodankylän Tähtelään ensimmäisenä työpäivänä saapuessani millaisen koko elämää tukevan isähahmon tapasin Johannes Kultimaa kätellessäni. Minulle oli jo etukäteen neuvottu, että tapaat myös Uulan, jonka saatat kokea kovasti värikkääksi ja omaperäiseksi persoonaksi. Hän on kuitenkin sydämessään koko humaanista arvomaailmaa tukeva ihminen, jonka puoleen voit kääntyä asiassa kuin asiassa. ”Voit luottaa häneen kuin herkkien magneettisten mittausten tarvitsemaan peruspilariin.” Siinäpä neuvo, joka kuulosti minusta tuolloin voimakkaalta tulevalle tutustumismatkalle sekä tieteeseen, että koko olemisen filosofiaan. Mutta luottamus osoittautui heti oikeaksi, ja totesin pian nimeäväni vanhimman poikanikin Uulan etunimen mukaan.

Johannes Kultima kirjurina magneettikentän
 absoluuttimittauksissa Kevolla 3.10.2014. 
Itse asiassa Uula otti aina observatorioon saapuvat nuoret tutkijat siipiensä suojaan, opettaen heille ettei tieteellisen työn laadusta tingitä, havainnot tehdään perinpohjaisesti valmistautuen ja havaintohetkiin omistautuen, koska luonnonhavaintoja ei voi uusia. Ne on tehtävä luonnon ehdoilla. Nykyisen Sodankylän geofysiikan observatorion, viime vuonna 100 vuotta täyttäneen tutkimuslaitoksen koko olemus kiteytyi hänen suhtautumisessaan observatoriotyöhön, tieteelliseen mittaukseen. Uula oli tähtimittaaja sananmukaisesti, hän oli koulutukseltaan tähtitieteilijä, hionut omin käsin metrisen linssin tieteelliseen kaukoputkeen Turussa ollessaan, ja Sodankylän Tähtelässä mitannut Maan napavariaatiota, siis pohjoisnavan epäsäännöllistä hyrräliikettä, havaitsemalla 5-metrisellä kaukoputkella Sodankylän yli kulkevia tähtiä jokaikinen kirkas talviyö 15 vuoden ajan. Uulalta jäi vain 2 yötä mittaamatta. Se on suoritus, johon tuskin kukaan muu olisi pystynyt, varsinkin kun ottaa huomioon, että kaukoputkihan on ulkolämpötilassa. Ensimmäisenä havaintoyönä, jona olin mukana, Uula totesi tiukasti: ”Älä sitten hengitä putken runkoon, se aiheuttaa lämpölaajenemista ja havaintovirhettä”. Niin, tietenkin sen jälkeen kun olin erehtynyt hengittämään.

Satelliittiaikakauden tulon lopettaessa Tähtelän tähtimittaukset, Uula vastasi observatorion magneettisista mittauksista, ja teki sen samalla tinkimättömyydellä kuin tähtimittauksetkin. Ja opetti sitä meille nuoremmille. Yksi nykyisistä nuorista tutkijoista totesikin: ”Ilman Uulaa en olisi koskaan tullut näihin hommiin. Uulassa oli parasta että hän arvosti kunnollista tieteentekoa ja tuki sitä hieman omanlaatuisella tavallaan ‘kultimoimalla’.” Hauska tarina oli kun Uula yliopiston ruokalippulaskuissa olleen viiden sentin pyöristysvirheen takia teki valituksen yliopistoon. Hallinto yritti pelata alas ongelmaa vähättelemällä, mutta Uula piti pintansa. Ei sen takia, että viisi senttiä olisi iso raha, vaan sen takia, ettei jatkossa hallinto tekisi samanlaisia tyhmyyksiä sortumalla pyöristysvirheeseen.

Uula otti mielellään uudet tutkijat mukaan tekemään magneettisia mittauksia, kertoen juurta jaksaen miten instrumentit toimivat ja miten mittauksia tehdään. Absoluuttimagneettikentän mittaukseen käytettävässä mökissä ei saanut olla ainuttakaan rautanaulaa. Jopa hänen silmälasiensa sangat oli valittu niiden magneettisten ominaisuuksien perusteella. Hän myös tarkisti tietokoneiden mittaamat käyrät hyvin tarkasti. Kun joku sattui tietämättään hiihtämään magnetometrikopin ohi, Uula hyvin hienovaraisesti seuraavana päivänä otti puheeksi suksen siteiden magneettiset ominaisuudet, ja miten niinkin pieni asia vaikuttaa herkkien magnetometrien tekemiin mittauksiin. Hän oli siis nähnyt häiriön magnetometrin mittauksissa ja yhdistänyt ne suksenjälkiin. 

Magnetismin perustyö ei ole ulospäin kovin näkyvää eikä siitä useinkaan synny suoranaisia tieteellisiä julkaisuja, mutta sitä kautta tiedeyhteisölle, niin Suomessa kuin kansainvälisestikin, tarjoutuu alan tutkimukselle korkeatasoista ja laatuvarmennettua magneettista dataa alan tutkimukselle. Sodankylän magneettiset aineistot ovat olleet lukuisissa tieteellisissä tutkimuksissa tärkeää ja arvokasta materiaalia yhdessä muiden maailman observatorioiden kanssa. Yhteistyöt Ilmatieteen laitoksen Nurmijärven observatorion kanssa, kansainväliset vertailumittaukset, ja kansainvälisen IMAGE-magnetometriketjun kalibroinnit olivat Uulan vastuita tiedeyhteisön hyväksi.

Tähtelässä Uula rakensi ja ylläpiti työyhteisön henkeä. Sekä ammattiyhdistystoiminta että yhteiset tapahtumat olivat lähellä hänen sydäntään, eikä ilman Uulaa olisi montaakaan marjaretkeä, tiedehistoriasta kertovaa näytelmää tai peräti työpaikan lumijalkapallo-ottelua noussut pystyyn. Uula piti koululaisista ja sai aikaan observatorion tutkijoiden kiertueen halki koko Lapin, jossa kerroimme revontulista ja avaruustutkimuksesta, kun Uulan ehdotuksesta syntynyt hakemus sai rahoituksen Lapin Kulttuurirahastolta. Uula toimi taustalla koko ajan tavoitteenaan ruokkia lasten ja nuorten tiedonnälkää, ja hän sai observatorion toimimaan Sodankylän päiväkoti Tähtitarhan kummilaitoksena, sekä pitämään revontuli- ja avaruuskursseja Sodankylän lukiossa. Hän selvitti historian tapahtumia ja kirjoitti niistä kansantajuisia artikkeleita, kuvaten saamelaisen tähtitaivaan ja joulun tähden tarinat.

Uulan kanssa oli hauska tingata. Hän oli kaikkien pitämä ja lämminhenkinen ihminen, joka tykkäsi rakentaa keskustelua kahvipöydässä - usein tarkastellen asioita eri näkökulmista ja lisäten sekaan hyväntuulista lappilaista tarinankerrontaa. Paljon Uulan elämänasenteesta kertoo se, että viimeisimmän Sodankylässä pidetyn väitöstilaisuuden karonkassa jälkiruuaksi söimme Uulan poimimia karpaloita kinuskikastikkeen ja tomusokerin kera.

Kun observatorio teki revontulien kenttämittauskampanjoita, Uula ratkaisi näppärästi käytännöt ongelmat lappilaisella neuvokkuudella – ja huumorilla. Ilman Uulaa moni asia olisi jäänyt järjestymättä, kuten kuljetukset läpi 40 km kairan Porojärven tunturikämpälle, huolto kesken kampanjan ja maittavat gourmet-ateriat makaronista ja nötkötistä. Uulan ansiosta asioilla oli omalla rauhallisella tavallaan tapana hoitua, eikä pitkistä oleskeluista tiettömissä kairoissa kymmenien kilometrien päässä muista ihmisistä olisi voinut ilman Uulaa uneksiakaan. Mittauskampanjoissa opimme, että kun Uula nukkuu, kaikki on hyvin!

Uula oli vielä eläkkeelle siirtymisensä jälkeen mukana työtehtävissä, oikoluki tekeillä olevia kirjoituksia ja digitoi käsintehtyjä havaintokirjoja viimeiseen hetkeen asti. Hän oli observatorion tutkijoiden mukana kertomassa avaruusaiheista päiväkodin lapsille ja lähti mielellään magneettisille kenttämittausmatkoille – ansaitusti kirjurina, kun muut olivat jo häneltä oppineet itse mittauksen tekemisen.

Nyt Uula nukkuu. Emme ole ihan varmoja onko kaikki hyvin. Tähtimittaaja lähti taivasmatkalleen yllättäen, liian pian. Jatkamme hänen työtään muistaen hänen opetuksensa. Opetuksesta on jäänyt miellyttävä ja valoisa muisto.

Uulaa kiittäen, Esa Turunen ja Sodankylän geofysiikan observatorion työntekijät

Johannes Kultima in memoriam

Johannes Kultima taking notes during absolute magnetic
field measurements at Kevo on 3rd October 2014.

Upon arrival at Tähtelä, Sodankylä, as a novice student of natural sciences I could not see what kind of father figure I met when I very first time shook hands with Johannes Kultima at the observatory.  I was advised beforehand that I might also find Uula in him, a colourful and original person.

Actually Uula always took newly arriving young scientists under his wings and taught them that you can’t compromise on the quality of scientific work: observations need to be properly prepared and carefully executed because every observation of nature is unique. He was a true Observer of the Stars: an astronomer by education, who honed, with his own hands, the 1-metre telescope lens at Tuorla observatory, Turku. After he came to Sodankylä he carried out with great care the observation of Earth's polar motion during every cloudless night using a zenith telescope. He missed only two clear nights during 15 years of observations.

After satellites began to measure Earth's precise motion, Uula was responsible for geomagnetic observations, which he continued with the same strict attitude to scientific precision. Even the frames of spectacles need to be selected carefully for observations. Magnetic field observations are still done in iron-free buildings. Once someone passed the geomagnetic observatory close-by on skies, and on the next day Uula diplomatically brought up the magnetic properties of the ski bindings and effects on the observations. He had linked the disturbance in the observations to tracks left by the skis at the magnetic observatory.

Basic geomagnetic observatory data, by themselves, rarely bring out new scientific results and publications, but they offer high-quality, validated observations for the global scientific community. Uula’s observations are unique measurements of nature at the time, and as such they stand as invaluable material for researchers.

Uula was a team spirit builder. Without him, we would not go to pick berries in autumn, have a play about the history of science or have a snow football game. He liked pupils and had a talent to awaken the curiosity of children about phenomena of nature. He arranged for observatory scientists to tour the schools of Lapland and tell facts about the northern lights and space research. He also came up with the idea of courses on these topics to be taught at the local upper secondary school. Uula was very interested in history and wrote popular articles, among others, about the stories of the Sami night sky and Star of Bethlehem.

Often Uula solved practical problems with finesse – and humour. Without him many things would have remained unresolved, like transport across 40 km of wilderness to the remote cabin of Porojärvi for a couple of weeks of scientific measurements. There, in the middle of nowhere, far from other people, he took care of matters in his own, unique calmness, and we couldn't have been there without him. During those measurement campaigns we learnt that when Uula sleeps, all is well!

Even after retirement he still proofed texts, digitised his old polar motion observations and visited kindergartens to tell about space. After having taught the art of magnetic measurements to the next generation, he loved to join measurement trips to the various magnetometer stations just to lend a hand even until October 2014.

Now Uula is sleeping. We are not quite sure if all is well. The Observer of the Stars left for his last journey unexpectedly, and too soon. We will continue his work reminiscing his teachings, which remain as fond and vivid memories.

Thank you, Uula,


Esa Turunen and the Staff of Sodankylä Geophysical Observatory

Friday, 14 November 2014

Hunting the green flash

Last week, during the CHAMOS workshop in Luosto, we climbed on the top of the Luostotunturi (514 m), and we reached the summit a few minutes before sunset (i.e. around 3pm). As the sky was clear and the horizon low enough, I tried to take pictures of the sunset, in the hope to catch the green flash.


Well, I have to admit that my camera's zooming capacities are not among its best properties. But still, if we have a closer look at the pixels corresponding to the solar limb...


There is definitely some green! The good thing is that I had never achieved this before. The bad thing is that now I want to buy a new camera to get better results...

To be continued (maybe)...

EDIT: The same story in French (with bonus pictures) here.

Wednesday, 12 November 2014

Treffeillä komeetan kanssa!

Tänään on jännä päivä, kun ihmiskunta kurottaa ensimmäistä kertaa pienen mutta suuren askeleensa komeetan pinnalle. Rosetta-luotaimen Philae-laskeutujan odotetaan tömpsähtävän 67P/C-G:n pinnalle tänään, 12.11.2014, n. kello 18 Suomen aikaa. Tapahtumaa voi jännätä suorana lähetyksenä Euroopan avaruusjärjestön verkkosivuilta.

Rosetassa ja sen Philae-laskeutujassa on runsaasti suomalaista Ilmatieteenlaitoksen ja Patrian avaruusosaamista. Ilmatieteenlaitoksen tutkimusprofessori Minna Palmrothin mainio suomenkielinen yhteenveto Rosetta/Philae -missiosta löytyy täältä.

Jos tämä onnistuu, niin torilla tavataan!




Sunday, 9 November 2014

Hyperlapse: BDU antenna construction

The Boston College & Bahir Dar University radar construction is running according to the schedule. Yesterday, I took this short hyperlapse film from the 'antenna plant'. I'll post antenna field pictures before I head back to the Observatory (departure Friday evening).

Pip-pip!


Friday, 7 November 2014

Bahir Dar coherent backscatter radar

I am still in Bahir Dar, visiting BDU physics and math departments. Today, our US colleagues (from Boston College and Burns Industries Inc.) arrived and started the VHF coherent backscatter radar build. This radar will operate at 49.9 MHz, 16 kW solid-state transmitter. The system will have 64 antennas. The sampling is based on a number of USRP X300-series boxes. Hence, today we feature photos from the Day 1 BDU radar build!

First antenna!!

Here's the future antenna field and control room.

USRP X300 -- these are for sampling!

... and the build continues!



Wednesday, 5 November 2014

CHAMOS workshop at Luosto!

SGO scientists, together with colleagues from Finnish Meteorological Institute, University of Otago (New Zealand) and British Antarctic Survey, have an active science collaboration for studying various solar activity effects on the upper atmosphere and climate. Our CHAMOS team stands for "Chemical Aeronomy in the Mesosphere and Ozone in the Stratosphere" and we have a sparkling workshop going on over this week at Luosto.

Suitably for the theme, last night we enjoyed the most beautiful northern light display.

This is coordination.



Tuesday, 4 November 2014

Afternoon sunset

Early November. We can almost enjoy sunset during our afternoon coffee break in Polaria at 13:30. After a couple of days with positive temperatures, the river is freezing again, showing these funny patterns. The following picture was taken from the shore near the main building of the observatory just a few minutes ago.

Photo: M. Grandin

Friday, 31 October 2014

Virkistyspäivä – "Refreshment Day"

On Wednesday, the staff of Sodankylä Geophysical Observatory spent a recreational day in Ahvenlampi, in Luosto. In Finnish, this is called virkistyspäivä. Weather permitting, outdoor activities are particularly popular in all seasons for such occasions.

Luckily, this was a dry day with slightly positive temperatures, which was particularly well suited for a treasure hunt designed in the same spirit as geocaching during the morning. The staff members were divided into three teams and had to find hints hidden around the pond.

The Virkistelijät team listening to the instructions before departure
Photo: M. Grandin
On their way, they collected sausage sticks, blue wool thread and some metal wire, which they needed to use to "fish" one of the last hints.

The Geotupeltajat team fishing
Photo: M. Grandin
Team work was strongly required to collect the final box containing the indications to find the treasure, which consisted in tikkupulla dough and The Password for lunch.

The Ryhmärymy team reaching the final box
Photo: M. Grandin
During the afternoon, the teams took part in a competition including several activities such as rubber boot throwing and a potato-in-a-spoon-in-the-mouth relay race.

The spoon-and-potato relay race
Photo: M. Grandin
After the competition, the participants all went to the laavu where they had coffee and made the tikkupullat ("stick buns", cooked above the fire). The final task consisted in a quiz about the observatory staff members, after which the points earned by each team were counted.

In the laavu
Photo: T. Ulich
This was a really pleasant and refreshing day, for which we warmly thank the best organiser ever, Iina Sirviö, who did a great job to make this event so memorable!

Tuesday, 28 October 2014

Revontulitalvi alkanut näyttävästi

SGO:n kamerat on kuvanneet Lapin taivasta noin kahden kuukauden ajan ja taivaalla on nähtävää riittänyt 70% öistä. Yleensä syys-lokakuu on pilvistä ja sateista aikaa, mutta tänä syksynä ainakin Lapissa on riittänyt ihan hyvin selkeääkin säätä revontulien havainnointiin. Varsinainen pimeän aika kestää jo 13 tuntia päiväpituuden jäädessä Sodankylän korkeudella alle 8 tunnin. Talviaikaan siirtyminen myös helpotti iltaunisten mahdollisuuksia nähdä revontulia. Alla koko viime yön revontulet, jotka päättyivät sykkiviin revontuliin aamun sarastaessa puoli seitsemän aikaan. Syksyn revontuliyöt löydät SGO:n galleriasta aina 27.-28.10. yöhön saakka.

video

Research Ethics

Euthanasia, animal testing, biofuels, Milgram experiment... Although in physics we do not have the same ethical issues as in biology, medical science or psychology, there are quite a few situations a physicist encounters in his scientific life which require being careful, be it while processing data, publishing a paper or making public statements. This blog post itself has been ethics-checked with the utmost care and contains no plagiarism nor bear any kind of conflict of interest.


In the University of Oulu, all the doctoral students are required to take a Scientific Research and Ethics course during their PhD. For some of them, it is a topic they never dealt with before.

THINK BY THEMSELVES

This course consists of a couple of general lectures introducing the concept of ethics from a philosophical point of view, followed by several field-specific lectures. This enables to treat differently the students in medicine or biology who may open people or animals to publish scientific papers, students in humanities who may make statistics from personal data to publish scientific papers and students in physics or mathematics who may publish scientific papers. Finally, a group work on a research-ethics-related topic and leading to a presentation during a seminar allows the students to think by themselves about what ethics involves, based on a concrete case.

And for those students who may fail this ethics course in this autumn term, another one will be held next spring. In Finnish. Lesson no. 1: don't mix it with vinegar.

Monday, 27 October 2014

Solar flare signature in the BDU riometer

There has been quite inspiring buzz in the media about the current "monster sunspot", and indeed, this giant AR2192 spot has sent multiple X-class solar flares towards us within the past few days. In addition to the widely reported HF-radio blackouts and GPS navigation disturbances, the energetic solar flares cause changes in the upper atmosphere/ionosphere due to increased photoionisation in the whole dayside hemisphere. SGO aims to quantify this ionisation by several ground-based measurement techniques, including riometers.

As mentioned in the earlier blog, we have just installed a new spectral riometer to Bahir Dar, Ethiopia and we were lucky to catch a few of these fresh solar flare events to the data, please have a look:


Received power (in arbitrary dB units) detected by the BDU spectral riometer (start, max and stop times of the solar flare event are marked as dashed lines).

One of the challenges in detecting the solar flare induced ionisation by riometry is that the Sun sends, not only the X-rays, but also bursts of radio emissions related to the flare events. As the riometer operates at the same radio frequencies, these emissions might mask totally the signature of the atmospheric response to the flare, i.e., reduction in the cosmic radio noise levels. 

In this case too, the increased levels of radio noise (red stuff) during the onset and offset phases of the flare are probably caused by the direct solar radio emissions. However, around the maximum time of the flare, there is a clear reduction in the radio noise, most likely caused by increased radio wave absorption in the ionosphere. We are particularly interested in the spectrum of this increased absorption (radio noise absorption at different frequencies) as it carries information on the ionisation profile in the atmosphere. 

This provides a very nice science case for collaboration between the SGO and BDU scientists and pretty awesome kick-off for this instrument, I'd say!


A few photos of the famous beauty & the beast:


www.spaceweather.com

www.spaceweather.com