Trainee Ave Ansper: one day on the skiing trail, another giving a talk at ESA

Kairi Janson | 19.02.2018

If someone had told Ave Ansper, the trainee of the observatory’s remote sensing of water bodies group five years ago that she would be holding a presentation at the European Space Agency (ESA) in 2018, she would not have believed it. „I’d rather have believed that I would go to the PyeongChang Olympics,“ she said. As a matter of fact, she would have perfectly fitted there as well.

Ave Ansper

The laureate of the last Juhan Ross scholarchip Ansper has made making satellite data work for us and other living things her goal. She uses the Sentinel-2 mission multispectral instrument data to evaluate the condition of Estonian small lakes.

The choice of major turned out surprising

After graduating from high school, Ansper thought about law, IT and landscape architecture as her possible future majors. She picked environmental protection just before having to confirm her major. “I had been wandering in Estonian nature right before that and got interested in studying something nature-related,” she said.

After graduating from the Estonian University of Life Sciences with a bachelor’s degree, Ansper wanted to try something more technical. Therefore she continued her master’s studies in environmental technology at the University of Tartu where she studies to date.

Having started her master’s studies, Ansper still did not think of picking remote sensing of water bodies as her major. At first, she wanted to start doing research in remote sensing of vegetation – the area that her bachelor’s thesis had been in. Now, however, she is more than happy to have picked remote sensing of water bodies. „My supervisor Krista Alikas managed to make this topic very interesting for me and right now I would not even imagine having chosen remote sensing of vegetation,“ she said.

Why to evaluate the levels of chlorophyll a and phytoplankton biomass

Ansper’s master’s thesis should be completed this spring. She uses both satellite and in situ measurements. „Satellite remote sensing is a very effective method which requires less money than in situ measurements,“ Ansper said.

The goal of Ansper’s thesis is to evaluate the water quality parameters of Estonian small lakes: the levels of chlorophyll a, phytoplankton biomass and transparency that show how dangerous or non-dangerous the water body is to living organisms.

Phytoplankton are microscopic organisms which can form large colonies. Phytoplankton contain chlorophyll (one type of which is chlorophyll a) and can therefore photosynthesize. “Due to the energy produced in the process of photosynthesis, phytoplankton are the agent of primary production which is an important part of the proper functioning of the aquatic food chain,” Ansper specified.

To evaluate water quality, the biomass of phytoplankton in the water needs to be assessed, Ansper said. According to that, the rate of nutrients in the water can be evaluated. The transparency of the water body indicates the underwater lightfield which is important to underwater plants and organisms.

„In case of algal blooms, all kinds of sediments and nutrients are in the water. These can increase the phytoplankton biomass. This is when the colour of the water turns green and intransparent, blocking the light from reaching deeper water layers,“ Ansper said. The bloom of one type of phytoplankton, cyanobacteria, is toxic and dangerous to human. It also hinders the vitally important processes of other organisms of the ecosystem.

At least a good status

According to the European Union Water Framework Directive, member states of the union should aim to achieve the objective of at least a “good” water status by defining and implementing the necessary measures within integrated programmes of measures. Ansper’s master’s thesis focuses on the way of evaluation that could be used for reports regarding the directive.

“The ecological status of the lakes has to be ascertained according to the type-specific base conditions,” Ansper said. The ecological status is determined depending on the biological, physicochemical and hydromorphological quality elements. Each element has fixed quality class boundaries according to which the status of the water body is evaluated.

For each element, remote sensing periods are agreed upon. Based on the results of a certain period, the average value of this period is calculated. The average value corresponds with one of the ecological status classes of surface water bodies: “high”, “good”, “moderate”, “poor”, or “bad”.

When the ecological status class of the surface water body is “good”, the values of the type-specific biological quality elements show that the water body is little affected by human activity. “If the water body belongs to the “good” or “high” quality class, this evaluation has to be supported by the physicochemical and hydromorphological quality elements. If these elements indicate a moderate status, the final quality class will be “moderate” as well,” Ansper explained.

A huge experience: presentation at ESA

In the end of January, Ansper got a chance to give a talk at the European Space Agency (ESA). „I was very nervous at first, but it actually wasn’t scary at all. Everyone was very supportive and friendly,“ Ansper stated. She said that holding a presentation at ESA was a huge experience.

It was a Sentinel-2 validation team meeting.  Sentinel-2  is an ESA land monitoring constellation of two satellites: one sent into orbit in 2015 and other in 2017. The spatial resolution (10 m, 20 m, 60 m) of Sentinel-2 is much better than the one of the satellites meant for remote sensing of water bodies and therefore the satellites can be used for the remote sensing of Estonian small lakes as well.

Because the signal coming back from lakes goes through atmosphere, it is important to clear the signal from the influence of the atmosphere. An atmosphere correction method is used for that. In ESA, Ansper talked about the comparison of four different atmosphere corrections used in the case of Estonian small lakes.

A fresh body keeps the mind fresh

Ansper knows that it is important that one keeps their mind fresh in everything they do. For Ansper, the best way to do that is sport. “I always take my sneakers with me when travelling somewhere for a longer amount of time – I’m just used to being active,” Ansper said.

Ansper has done many sports but since starting school, her main sport has been cross-country skiing. By now, she has participated in many international competitions and already teaches others. Among other things, she has been a skiing instructor in Australia. „Constant training has been great help in other parts of my life as well because it teaches consistency and the sense of duty,“ Ansper said.

Those qualities have surely paid off. Last autumn, the observatory appointed the Juhan Ross scholarship to Ansper. She was the only master’s student among PhD students. „Other scholarship earners are, of course, role models for me as a master’s student,“ Ansper said.

Ave Ansper ESAs
Ave Ansper at the European Space Agency
Ave Ansper ESAs
Ave Ansper holding a presentation at the European Space Agency