International Incoherent Scatter Radar School: Sodankylä 2016

We have the pleasure to announce the upcoming International Incoherent Scatter Radar School on 24–30 July 2016. This summer school will be held in Sodankylä, and is jointly organised by the Sodankylä Geophysical Observatory and SRI International. It is sponsored by the EISCAT Scientific Association and the US National Science Foundation (NSF).

The purpose of the summer school is to provide graduate and advanced undergraduate students with a solid background on the incoherent scatter radars, from the underlying theory of incoherent scatter to the design of radar experiments and data analysis, with a strong practical component. In particular, the students will be given the opportunity to design and run their own experiments using the EISCAT radar system, and then to analyse their data sets.

The school will be organised as follows. The lectures will take place during the morning sessions, from Monday 25 until Friday 29 July. The afternoon sessions will be dedicated to hands-on work in  small groups, with the objectives of designing a radar experiment suitable to study a chosen physical phenomenon, and of analysing the obtained data accordingly. There will also be many opportunities for students to directly interact with the lecturers during these sessions. The experiments will be run during the 26-27 July night. On Saturday 30 July morning, the groups will present their results to all  the summer school participants.

The school will take place near the beautiful banks of the river Kitinen.

Photo: M. Grandin

All students will be hosted at the local vocational school in Sodankylä, and meals (breakfasts, lunches and dinners) will be provided.

The deadline for submitting an application is 6 March 2016. The selected participants will be notified by 29 March 2016.

More information and detailed instructions for application can be found on the following webpages:

- EISCAT participants: http://www.sgo.fi/Events/RS2016/index.php

- US participants: http://www.amisr.com/workshop

For any inquiries, please contact RS2016(at)sgo.fi (EISCAT/SGO) or summerschool(at)esd.sri.com (US NSF).

Geminidien tähdenlentoparvi ja 6.12. tulipallo SGO:n tulipallokamerassa

Tänä vuonna säät suosi viime vuotta paremmin Geminidien tähdenlentoparven havainnointia Lapissa. Ainoastaan tiistaiaamuyön 15.12. tähdenlennot jäi pilvisen taivaan taakse. Tulipallokameran automaattinen eventtien tunnistusohjelma poimi 12.-16.12. välisenä aikana yhteensä 75 eventtiä. Näistä 12.-13.12. välisenä yönä tallentui 24 eventtiä ja 13.-14.12. yönä  35 eventtiä, kun tyypillisesti kamera tallentaa 3-5 eventtiä yötä kohti, johon mahtuu myös satelliitteja ja kirkkaita revontulia.

Pimeän ajan (15UT-06UT) tunnittaisten maksimipikseliarvokuvien summa SGO:n tulipallokamerasta 12.-16.12. 2015 väliseltä ajalta. Kuvassa erottuu myös 14.12. illan kirkkaimmat revontulet.

 SGO:n tulipallokamera on WATEC 902H3 (1/3")

 varustettuna 2.8mm laajakulmalinssillä antaa

 noin 65° kuva-alan taivaalta.

SGO:n tulipallokamera toimii revontulikameran rinnalla. Kameralla on tarkoitus tukea SGO:n muita havaintoja ja aineisto on yhteistyökumppaneiden käytettävissä. Samalla kamera täydentää Lapin muuten harvaa automaattista havaintoverkkoa. Etenkin ennen URSA:n Taivaanvahti-järjestelmää SGO sai runsaasti havaintosoittoja kansalaisilta. Tällä hetkellä SGO käyttää Eric Stamplesin (Uppsalan yliopisto) kehittämää ohjelmistoa Ruotsin tulipallokameraverkolle, jota myös SGO:n yhteistyökumppani IRF Kiirunassa käyttää. Kyseinen ohjelmisto tallentaa vain tunnistetut eventit.

Tulipallokameran monitoroima taivas merkittynä punaisella 

laatikolla UCL:n revontulikamerakuvaan. Tällä hetkellä kamera on suunnattu

lähes zeniittiä kohti.

Useimmat URSA:n Taivaanvahti-järjestelmään raportoidut tulipallot jäävät SGO:n kameran kuva-alan ulkopuolelle. Laajakulmalinssin vaihto kalansilmälinssiin auttaisi asiaan ja on suunnitelmissa. 

6.12. 2015 SGO:n tulipallokamera kuitenkin tallensi osittain Pohjois-Suomen taivaalla havaitun kirkkaan tulipallon, josta tehtiin myös äänihavainnot Kittilässä ja Sodankylässä. Kyseinen tulipallo tallentui 4 sekunnin ajan SGO:n kameraan.

Effects of solar wind high-speed streams on the high-latitude ionosphere: Superposed epoch study

Our study of the effects of solar wind high-speed streams on the high-latitude ionosphere, based on data from the SGO ionosonde during the years 2006–2008, has now been accepted for publication. An early-access version is available here, and the reference is:

Grandin, M., A. T. Aikio, A. Kozlovsky, T. Ulich and T. Raita (2015), Effects of solar wind high-speed streams on the high-latitude ionosphere: Superposed epoch study, J. Geophys. Res. Space Physics, 120, doi:10.1002/2015JA021785.

Here is the abstract:

Solar wind high-speed streams (HSSs) are the most important source of geomagnetic disturbances during the declining phase of the solar cycle. Their ionospheric response, especially at high latitudes, is not fully understood yet. We carried out a phase-locked superposed epoch analysis to study the effects of HSSs on the high-latitude ionospheric F region, using data from the Sodankylä ionosonde (L = 5.25) during 2006–2008. We found that the F layer critical frequency f_oF₂ decreases between 12 and 23 magnetic local time (MLT) in summer and around equinoxes for several days. Our interpretation, supported by numerical estimations, is that increased electric fields in the evening sector of the auroral and subauroral regions create ion-neutral frictional heating. Frictional heating will increase the loss rate of O⁺ due to two reasons. The first one is neutral heating producing thermal expansion of the atmosphere and enhancing N₂ and O₂ contents at the F region peak. The second one is ion heating which may occur under strong enough electric fields (about 50–60 mV/m), leading to enhancement of the reaction coefficients. An increase in f_oF₂ is observed in two different MLT sectors. First, a short-lived f_oF₂ increase is visible during all seasons near noon on the first day after the arrival of the HSS, possibly triggered by the compressed solar wind plasma pressure pulse, which may produce particle precipitation from the dayside central plasma sheet. Second, f_oF₂ is enhanced for several days in the morning sector during equinoxes and in winter. We suggest that this is caused by the low-energy tail of particle precipitation.

Variations of foF2 and max(foE, foEs) values compared to background values, by magnetic local time and day number relative to zero epoch. ©2015. American Geophysical Union.

Sodankylä ionospheric tomography dataset 2003–2014

At Sodankylä Geophysical Observatory, we have made continuous ionospheric tomography measurements for one solar cycle. Because of this big database, we have written a dataset paper, and, the paper is now online as a discussion paper in Geoscientific Instrumentation, Methods and Data Systems (an EGU journal).

The number of satellite overflights over the 
whole observation period with respect to 
minimum threshold elevation. 

In the paper, we show that ionospheric tomography results are modulated by the solar cycle, which can be seen from the analysed data. We have altogether measured over 66,000 flybys of the Russian COSMOS beacon satellites. For the analysis, we used only north-to-south flights, because they are along the SGO ionospheric tomography chain.

In the figure below, we have plotted the analysed total electron content (VTEC) values over Kokkola, Finland (averaged from 11-14 MLT). These are compared to the well-established Sun activity indices, the sunspot number and the solar flux index F10.7.

The paper is fully citable as:

Norberg, J., Roininen, L., Kero, A., Raita, T., Ulich, T., Markkanen, M., Juusola, L., and Kauristie, K.: Sodankylä ionospheric tomography dataset 2003–2014, Geosci. Instrum. Method. Data Syst. Discuss., 5, 385-404, doi:10.5194/gid-5-385-2015, 2015.

... and here's the abstract:

Sodankylä Geophysical Observatory has been operating a tomographic receiver network and collecting the produced data since 2003. The collected dataset consists of phase difference curves measured from Russian COSMOS dual-frequency (150/400 MHz) low-Earth-orbit satellite signals, and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003–2014, there were three-to-five operational stations at the Fenno-Scandinavian sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60°. These constraints limit the number of overflights to around 10 000. Based on this dataset, one solar cycle of ionospheric vertical total electron content estimates is constructed. The measurements are compared against International Reference Ionosphere IRI-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model are on average 40 % higher of that of the tomographic results.

VTEC values over Kokkola averaged from 11-14 MLT 
versus corresponding IRI-2012 model values, 
sunspot number and solar flux index F10.7. 

Northern Lights

It's been very cloudy this past month, with few clear nights. Often we saw in our instruments that there must have been brilliant lights on the other side of the clouds, but on the ground there was no chance to see anything. Then, on Wednesday evening (2nd December), there were gaps in the clouds and for a brief moment the lights appeared...

With this photo we wish all of you a very good weekend, and those of you in Finland a very good Independence Day on 6th December, when Finland will turn 98. Hyvää Itsenäisyyspäivää!

Photo: Thomas Ulich.

International Incoherent Scatter Radar School 2016

In the near future the EISCAT Scientific Association will face a major instrumental upgrade with the ESFRI Roadmap project "EISCAT_3D: A European Three-Dimensional Imaging Radar for Atmospheric and Geospace Research."

The NSF and EISCAT, in co-operation with the Sodankylä Geophysical Observatory, will run a training course for new users of the incoherent scatter radars, from 24 to 30 July 2016 (Sunday to Saturday). The training course will be held in Sodankylä, where one of the EISCAT VHF remote sites is located.

The course will cover all essential aspects of the current incoherent scatter radar systems, including the science programme. An overview of the existing hardware and software was provided and future plans will be discussed, with an emphasis on phased array radars in preparation of EISCAT_3D.

The course will have a very strong emphasis on practicals, i.e. work in groups of participants on real data. There will be dedicated radar experiments for every group, and the groups will analyse their data and present their results under the guidance of an experienced team of instructors.

For more information, please refer to the radar school web pages.

Deadlines for registration are still undetermined, and we will provide more information soon.

Photo: Craig Heinselman, EISCAT.

Observatory Days 2016

On 13–15 January 2016, Sodankylä Geophysical Observatory will host its Observatory Days. It is a great opportunity for space physics researchers to discuss the latest scientific results, current projects as well as future plans for development.

The presentations and discussions will be in English. Interested scientists from any country and institute are therefore welcome to participate!

Please note the deadline for registration and abstract submission: 7 December 2015.

More information is available on the dedicated webpage.

We look forward to welcoming you in January!