Friday, January 5, 2018

2018: Centre of Excellence of Inverse Modelling and Imaging

Happy New Year 2018!

They are plenty of new things in my academic life. I am officially back at Finnish Meteorological Institute, now with the title “Senior Research Scientist.” Because of the large organization change at FMI, the name of my group is now entitled “Greenhouse Gases and Satellite Methods” in Earth Observation Research Unit.

Centre of Excellence of Inverse Modelling and Imaging: applications.
Probably the biggest news story is that now also our FMI team is part of the new 2018–2025 “Centre of Excellence of Inverse Modelling and Imaging.” The University of Helsinki team, the team where I had the pleasure of visiting for the last seven months, coordinates this Centre! We will have the kick-off meeting next week at Uunisaari. It will be fun!

Regarding this site, I updated my Biographical Sketch. Enjoy!

In the next post will recap my experiences from Slush 2017 Skolar Award.

Stay tuned!


Thursday, November 30, 2017

Slush 2017 Skolar Award Science Pitching

Hi guys!

I am very happy to say to that I am on of the ten finalists for the Skolar Award Science Pitching competition happening at Slush 2017 tomorrow! This means that I have amazing change to pitch my research idea in front of 2 000 people for three minutes! I will give everything I got!

Here’s my research idea in a nutshell:
As everyone should realize by now, climate change is one of the biggest threats to humanity. The main culprits are atmospheric greenhouse gases, GHGs, that increase the global temperature. This research aims to identify the main man-made areas of greenhouse gases with the help of space-based observations. Those offer a sustainable and cost-efficient tool to estimate the impact of human activities on our environment.
You can meet the finalist at and

Yesterday morning I was in the Yle morning show talking about my idea. The interview went really well, and you can watch it from Yle Areena:

Yesterday evening we had The Skolar Award Premiere at the Kaskas Media HQ. Now I should be ready!

See You at Slush Central stage tomorrow at 13:10 Finnish time. You can follow the event online at



Friday, October 13, 2017

Eye in the Sky

Dear friends,

It is my pleasure to announce that the prestigious journal Science has published a collection of five research papers based on OCO-2 data.

The main finding of this special issue was how the 2015-16 El Niño, one of the largest on record, was responsible for the record spike in carbon dioxide levels. The increase was about 3 ppm per year,  while in recent years, the average annual increase has been closer to 2 ppm per year. According to  Dr. Junjie Liu who led the study "about 80 percent of that amount, or 2.5 gigatons of carbon, came from natural processes occurring in tropical forests in South America, Africa and Indonesia, with each region contributing roughly the same amount."

I wasn’t part of that study, but I had a little contribution to the paper "The Orbiting Carbon Observatory-2 early science investigations of regional carbon dioxide fluxes" with XCO2 anomalies. Here’s a little video from Science Museum of Virginia explaining how the anomaly approach work:

You can find the OCO-2 special issue here:


Wednesday, June 14, 2017


Dear readers,

Last week the 13th International Workshop on Greenhouse Gas Measurements from Space (IWGGMS) was held at the main building of the University of Helsinki. The meeting had a very good atmosphere, and with about 160 participants, I got to talk with many new and old GHG colleagues, and once again learned a lot! Here are couple of photos.

Thank you for the meeting!


Opening talk by Dr. David Crisp

That's me presenting my work!
Dr. Iolanda Ialongo presenting her poster
Our PhD student Ella Kivimäki presenting her poster
Dr. Hannakaisa Lindqvist presenting her posters

Group photo!

Wednesday, May 31, 2017

Back to the start

Dear readers,

I started my academic life in 2004 as a math student in University of Helsinki. I enjoined my time there, although, one of the best experiences of my “university years” was the academic year 2006/2007 that I got to spent in Roma Tre University as an Erasmus exchange student. During the later part of my studies, in 2008, I joined the Atmospheric Remote Sensing group of the Finnish Meteorological Institute first as a summer trainee, then as a master’s thesis worker, and finally as a research scientist. I never looked back, and went to do my PhD studies in Lappeenranta University of Technology (2011–2013). This means that I never actually worked for my alma mater.

Tomorrow that is about to change, as I will join the Inverse Problems research group in the Department of Mathematics and Statistics until the end of this year. I am excited about this opportunity and will try to learn as much as I can during the next seven months. Research-wise, this is also an excellent opportunity to study the different aspects of the inverse problems research.

Actually, I will start my first full week as a university employee in the “13th InternationalWorkshop on Greenhouse Gas Measurements from Space.” Finnish Meteorological Institute organizes the meeting, but it will be held in the main building of… University of Helsinki!

See you there!


Saturday, December 10, 2016

Direct space-based observations of anthropogenic CO2 emission areas from OCO-2, Part II

Dear readers,

the previous blogpost was about the public outreach of our latest paper: "Direct space-based observations of anthropogenic CO2 emission areas from OCO-2."

However, the blogpost itself did not mention the scientific content of that paper at all. As I presented this work as a poster at the OCO-2 Algorithm and Science Team Meeting at NCAR Mesa Lab in Boulder, Colorado earlier this year. I would like to share the poster with you now

The meeting itself was absolutely fantastic, and I learned a lot. We also got to see a AirCore launch which was fun


Direct space-based observations of anthropogenic CO2 emission areas from OCO-2

Dear readers,

it has been a while since I have blogged last time. But there has been a good reason. I have been busy with our latest work "Direct space-based observations of anthropogenic CO2 emission areas from OCO-2". In comparison to many of my previous works, the public outreach with this one has been through the roof. For example JPL/NASA published a news feature about it

The same text was also published as a press release at the front page of FMI website. It was also picked-up by many news outlets like the Daily Mail and Tähdet ja Avaruus from Finland, to name a few. One of the funniest was this newspaper clipping we got all the way from Katmandu

We made also a Finnish press release about it.

NASA EarthObservatory made new elegant figures for their image of the day feature. Those images were further included for example in this article.

I have gotten so many emails about this work from journalist, scientist, teachers, and ordinary people alike. Literally, everyday. Two of the questions from readers of NASA EarthObservatory, with responses, were published in a follow-up

Today also come out new Tiedelehti. There’s a "Tieteen tentti" with a familiar face

I wrote also an article, suitable for the general public, to the next Ilmansuojelu -lehti, 4/2016. It will come out later this month.

Earlier this week, I gave a guest lecture at Lappeenrant University of Technology. The XCO2 anomaly data together with OMI NO2 data were also given for the students for their study assignment related to cluster analysis.

This research has also trigged many new scientific collaborations, and there will be many new adventures. I will promise.

Stay tuned!


Tuesday, August 16, 2016

Pawan K. Bhartia – the man who created the first image of the ozone hole

Hi guys,

couple of days ago, I found this very interesting Youtube video of “Pawan K. Bhartia Maniac Lecture, August 27, 2014.”

In the video P.K. talks about his career and how the discovery of the ozone hole come about. It is a very interesting story.

See also “Discovering the Ozone Hole: Q&A With Pawan Bhartia” and “Ozone Hole History.

Oh, and this is the very first image of the ozone hole:

Very powerful image!


Friday, May 6, 2016

CARB-ARC: Remote sensing of greenhouse gas concentrations #Arktiko


next week I'm headed to the Academy of Finland's annual ARKTIKO seminar.  Below you can find the poster I'm about to present. It summarize the remote sensing activities done in our CARB-ARC project.


Saturday, April 16, 2016

The Audacity of Hope: President Obama Explains How Pollution Affects Our Planet


have you guys seen this already!? In this video President Obama speaks about OMI data. And if you didn't know, OMI  is a Dutch-Finnish satellite instrument  onboard NASA's Aura spacecraft etc.

Btw. See you next week in EGU! Maybe I will do some live posting from there...


Friday, April 1, 2016

Using OCO-2 Data to Analyze Anthropogenic CO2 Hotspots: First Preliminary Results


just submitted the abstract below to the "12th International Workshop on Greenhouse Gas Measurements from Space." I am not going, but our boss Johanna Tamminen will present this.


Using OCO-2 Data to Analyze Anthropogenic CO2 Hotspots:
First Preliminary Results

Janne Hakkarainen (1), Iolanda Ialongo (1), and Johanna Tamminen (1)
(1) Finnish Meteorological Institute (FMI)

NASA’s Orbiting Carbon Observatory 2 (OCO-2) was launched on 2 July 2014 to monitor global atmospheric concentration and flux of CO2 from space. As of March 2016, the instrument has collected more than one year of data. In this paper, we utilize this data record to analyze hotspots of anthropogenic CO2 sources. Our aim is to utilize advanced techniques developed to analyze spaceborne nitrogen dioxide (NO2) and sulfur dioxide (SO2)both short-lived atmospheric trace gases with both anthropogenic and natural sourcesdatasets. Unfortunately, trends, seasonality, long lifetime, and large atmospheric background significantly complicate the analysis of CO2 hotspots. Our methodology is based on simultaneously deseasonalizing and detrending the data, and then mapping the remainingthe so-called anomaly datato a grid.  
In this paper, we show that the main anthropogenic pollution regions like eastern USA, Central Europe, East Asia, and Middle East are easily detectable from our OCO-2 CO2 anomaly maps. In addition, also smaller sources are visible. In order to better understand CO2 anomaly maps, we simultaneously analyze the established NO2 and SO2 mapsobserved by Dutch-Finnish Ozone Monitoring Instrument (OMI) onboard NASA’s Aura spacecraftand use these data records also to qualitatively validate our results. In future, as the OCO-2 data record gets longer, we hope to individually detect all the Megacities.

Keywords: OCO-2, carbon dioxide, anthropogenic emissions, hotspots, validation, OMI, nitrogen dioxide

Tuesday, March 29, 2016

Pavlof, Alaska volcanic eruption 2016


yesterday OMPS observed volcanic SO2 plume from Pavlof eruption with three overpasses:

The data are acquired and processed by GINA/UAF and posted at FMI Direct Readout web site:

Note that also ash was observed:

Zoom it!


Friday, March 11, 2016

Generalized correlation integral vectors: A distance concept for chaotic dynamical systems


I’ve been about to blog about our ”Generalized correlation integral vectors: A distance concept for chaotic dynamical systems” paper for a quite some time. Now, I have a good option, since I’m about to go EGU general assembly for the first time this April.

Below there’s my poster that I’m about to present. The motivation for this methodology comes from our NOVAC project where the aim was to analyze the climate models.

See you all in EGU,


Thursday, March 3, 2016

Time series of methane and carbon dioxide


my colleague Hannakaisa Lindqvist recently published a paper with a fancy title: “Does GOSAT capture the true seasonal cycle of carbon dioxide?” This summer we are taking a summer trainee to study that same question for methane.

Today I decided to do a little bit of our summer student's work and plotted TCCON time series of methane and carbon dioxide in the same figure. These figures came out so nice that I want to share theme with you guys.


Wednesday, December 2, 2015

Random projection in a nutshell

I was reading the random projection paper – written by Teija Seitola et al. – the other day, and I think I have now quite a good understanding of how the method works.

The whole thing is based on Johnson–Lindenstrauss lemma from 1984. The lemma says that random projection (nearly) preserves the distances.

Let X be a n×d-dimensional data matrix, where n is the number of data (or ensemble) points and d is the actual dimension. Let f be d×k-dimensional random projection matrix. Let xi and xj be d-dimensional data vectors and ε>0. Now we have that

(1-ε)×ǁxi-xjǁ2 ≤ ǁf(xi)-f(xj2 ≤ (1+ε)×ǁxi-xjǁ2.

In the paper there are also to explicit formulas for k that surprisingly do not depend on the dimension d, but only on the number of observations n and the error ε. For example, k > 4×(ε2/2-ε3/3)-1×log(n).

So if, for example in correlation dimension, we set n = 2000 and ε = 0.1, we need k that is higher than 4*(.1^2/2-.1^3/3)^(-1)*log(2000) = 6515.1. I tested this with 320-dimensional Lorenz and set k to 10000 and the thing works since the curves became so similar (see figure below).

As a conclusion, I would say that random projection method works “better” in large than small dimensional problems, and that the dimension have to be really large before it is worth to use random projections in applications where the preservation of distances is very very important. Note that there are other kinds of applications too…

Below, there is a little Matlab example.


%% Random projection Matlab example

n = 2000; % Number of time points
d = 20000; % Dimension
k = 10000; % Random dimension

X = 10+5*randn(n,d); % Data matrix

R = randn(d,k); % Random projection matrix
for kkk = 1:d
   R(kkk,:) = R(kkk,:)/norm(R(kkk,:)); % Normalization

P = X*R; % Projection

% Distances
ii = 10; jj = 20;