Understanding the “bigger picture” is imperative if we want to address environmental concerns in the near and distant future!
Arnab Muhuri, PhD, our next pathbreaker, is a Postdoctoral Fellow at the University of Sherbrooke (Quebec, Canada), developing Earth observation algorithms to extract information from satellite images to address interdisciplinary research questions and real-world challenges.
Arnab talks to Shyam Krishnamurthy from The Interview Portal about his research experience on developing such algorithms and their relevance in dealing with problems ranging from national security to natural resource conservation.
For students, if you are planning to take unknown career paths, the ability to turn deaf ears to peoples’ opinions is a crucial trait. Value your dreams and have the courage to follow them!
Arnab, what were your growing up years like?
Let me commence by confessing that I had an excellent upbringing. My parents never had any expectations or plans for me. They just allowed me to enjoy my childhood. Being a single kid I enjoyed undivided attention from them. My dad is a civil engineer, so I got an opportunity to travel around the country and absorb the rich diversity. I grew up visiting mega construction sites like nuclear reactors and underground hydropower plants. Coming from a Bengali family, food was certainly my top priority. So perhaps that impacted my childhood dream to become a chef, though as I grew up, priorities changed and I wanted to be a cop.
Unlike the societal norm, I was never under the pressure of choosing a career path. I was (and still am) a happy-go-lucky kid, and so I took things as they came my way. My parents introduced me to sports at an early age and that really helped to shape my attitude towards coping with failures. My coach, Mr Mandar Ranade, was (and still is) an inspiring personality. At one point I was offered a chance to play professional badminton for Delhi, but being aware of the scope and challenges, I calculated my odds and settled for engineering.
What did you do for graduation/post-graduation?
Since I was bad at memorizing things, Social Sciences and Humanities were certainly not my cup of tea. Rather, I wanted to pursue something where I could build upon basic fundamental concepts. Therefore, I opted to study Electrical engineering. That was perhaps one of the best decisions of my life and I really enjoyed it! Sometimes I feel studying Economics could have been interesting, maybe in the near future.
When I finished my engineering I was not ready to take up a regular job. I knew that path since my dad had a corporate job at HCC. So I set myself on something unknown. Traditional post-graduate programs in Electrical Engineering were crowded, which meant joining the redundant workforce. The domain of Satellite Earth observation was (and still is) still a fairly unknown sector. So I grabbed this opportunity and pursued my Masters and PhD in this domain.
What were some of the drivers that led you to such an offbeat, unconventional and unique career?
As I mentioned before, I opted for Electrical Engineering because cramming was (and still is) not my thing. So at the undergraduate stage, my decision was driven by my understanding of my personal limitations. At the postgraduate level, my decision was influenced by the market. Joining the traditional specialization would have meant following the herd and repeating the same story.
I always found great joy in exploring uncharted territories and that’s what I did!
If I have to give credit to someone in my life who inspired me, it would perhaps be my badminton coach and other sports personalities like Pullela Gopichand, Sachin Tendulkar, and Roger Federer. Other than this, it was all about how I perceived the moment and followed my intuition. One needs to develop a gut feeling about the situation they are in and listen to their intuition.
After finishing my Bachelors in Electrical engineering, I pursued my Masters research at the Microwave Remote Sensing (MRS) lab at IIT Bombay under the supervision of Prof. Avik Bhattacharya. MRS lab focuses on the development and applications of algorithms for information extraction from satellite based radar images. My thesis was focused on finding appropriate probability distribution models for satellite radar signals recorded over agricultural fields in the Netherlands. Such mathematical techniques are employed for the classification of crop types growing over agricultural lands. The Masters program offered a good exposure to a comprehensive set of Earth observation methodologies.
After my Masters, I spent some time soul-searching and exploring the domain of planetary Earth observation. The objective of this investigation was to look for water ice deposits in the Lunar craters located around the near-polar regions. Contrary to popular belief, the results indicated that the observed radar signatures may arise due to scattering from the mixture of fine regolith and scattered rock, which are common features inside the crater. The investigation concluded that the presence of water ice was not a necessary requirement to observe the kind of radar signature, which is often strongly associated with water ice. This investigation was conducted in collaboration with the Indian Space Research Organization (ISRO), Department of Space, Government of India. Although planetary remote sensing is an interesting domain, for my PhD research, I was looking for something that more closely impacts humanity.
Tell us about your career path in Research. What was your PhD research on?
My PhD research was funded by the Department of Science & Technology, Government of India. The investigation was conducted in collaboration with the Defense Research and Development Organization (DRDO), the Ministry of Defense, and the Government of India. Considering the range of seasonally snow-clad mountains bordering the northern frontiers of India, it is relevant both from the national security and natural resource conservation perspective to continuously monitor the extent of the snow-covered area over the remote vastness of the mountain range. Although optical satellites can observe snow cover in the
In the most reliable manner, the dependence of such systems on solar illumination and the obscuring action of cloud cover poses a significant limitation. Under such limiting circumstances, active radar satellites can penetrate through clouds and darkness to help reveal the landcover. Although a number of landcover classification algorithms have been proposed in the literature, with satellite synthetic aperture radar (SAR) data, there was a lack of such target identification techniques for identification of snow cover in alpine areas.
My doctoral research addressed this issue through the development of novel snow cover identification techniques applicable for both dual-polarimetric and full-polarimetric satellite SAR systems. Unlike the optical snow identification technique that exploits the spectral variation in the reflectance in different wavelengths, the radar-based techniques focus on the target backscattering information sensitive to the structure, dielectric, and density of the volume of snow cover. The snow metamorphic state and radar scattering were found to be correlated. This scattering behaviour was exploited for monitoring the seasonal snow precipitation over the Indian Himalayas.
Optical satellites are still operationally preferred due to the distinctly high albedo characteristics of snow cover, which are reliably captured by multispectral sensors. The recent growing number of citations of my work, particularly by the Polar and Cold Regions group of the German Aerospace Center (DLR), indicates an increasing momentum in the direction of employing polarimetric satellite radar observations for cryospheric monitoring.
During this work, I had several opportunities to travel to the Himalayas for field experiments. Monitoring the extent of snow cover is an important task since meltwater feeds the rivers and other underground water resources. Such techniques help in forecasting the available reserve of hydropower for the forthcoming summers and influence national policies like the purchase of coal and nuclear fuel, which in turn influences the national economics.
What were your plans after your PhD and how did you go about executing them?
After a PhD, one has the option to continue with research at an academic/government institution or move to a corporate job. This decision is driven by one’s personal calling and preferences. Often, the objectives in a corporate job are determined by the projects/clients that a company is catering to. Some like to be told what is to be done while others like to pave their own path. So this decision is determined by the desire to either follow or lead.
Academic positions after PhD allow one to plan their own research path and pursue it. The Alexander von Humboldt fellowship is a prestigious opportunity awarded by the German government to a handful of PhDs from every country. The selection process is lengthy and stringent. After my PhD, I was awarded an opportunity by the German government to continue my research at a university of my choice in Germany. The history and reputation of Heidelberg University (established in 1386) appealed to me so I opted for Heidelberg. After living in metropolitan cities with millions of inhabitants I moved to a small town with around 150,000 people. During this period I was also a visiting scientist at the French Space Agency (CESBIO) in Toulouse, France where I got to expand my collaboration with other researchers from around the world.
In 2021 I moved to Uni Sherbrooke in Quebec, Canada to work with RADARSAT-2 and RADARSAT Constellation Mission (RCM) for soil moisture application. After a PhD one has wide opportunities to move around the world and work with different research groups focusing on specific sub-domains.
Can you explain the real world significance of your postdoctoral work at Heidelberg University?
The work looked at multispectral optical satellite sensors employed for operational snow cover monitoring, which was a complementary contribution to my doctoral work on Earth observation of snow cover with satellite radar sensors. Past investigations have reported significant degradation in the performance of the classical snow cover mapping approaches derived from multispectral optical airborne/spaceborne sensor data, upon transitioning from non-forested to forested landscapes. This occurs since the overlying forest elements offer obstruction to both the incoming downwelling radiation and the upwelling reflectance from the snow-covered forest floor. The degree of obstruction offered by canopy elements to the forest floor signature is determined primarily by the canopy gap fraction and the visible gap fraction. Thus, forest reflectance during winters, with snow overlying the forest floor, is determined by the fraction of sunlit snow visible through the canopy. This obscuring effect of the forest cover impacts the operational monitoring of snow cover in forested environments while using optical sensors.
The objective of this work was to understand and upgrade the performance of snow cover monitoring algorithms employed by the Copernicus Snow & Ice Monitoring Service, an operational service offered by the European Environmental Agency (EEA). The work involved large-scale processing and validation of the operational “under canopy snow cover” mapping algorithms in a variety of locations worldwide. This included the snow impacted locations across the European Alps and the Pyrenees, the Black Forest mountain range in Germany, and the Sierra Nevada mountain range in the western United States. This work exploited the processing potential of the French Space Agency’s (Center National D’Etudes Spatiales (CESBIO)) high-performance computing (HPC) facility. The upgraded state of the operational snow cover monitoring algorithm at high spatial & temporal resolution will result in the reduction of forecasting errors for agencies utilizing this service. The EEA provides land cover maps to 33 members and 6 cooperating countries in the Western Balkans.
During the proceedings of this investigation, a major rock and ice avalanche disrupted life around an inhabited portion of the Indian Himalayas. As a preliminary step to disaster response, a massive interdisciplinary collaboration was put together by domain experts from around the world. This investigation on the 2021 Chamoli disaster in the Himalayas was published in the prestigious Science magazine and covered by international media houses like BBC.
How did you get your first break?
After my PhD, I was offered an opportunity by the Alexander von Humboldt Fellowship by the AvH Foundation, Government of the Federal Republic of Germany to pursue my research at Heidelberg University in Germany. This decision was solely based on my academic and research contributions to the domain of satellite Earth observation.
What were some of the challenges you faced? How did you address them?
Let us not call them ‘Challenges’ but some essential ‘Traits’ one needs to possess.
Trait 1: Patience
In the long run, it is not about how intelligent one is but how patient one can be. The supply of patience can run out faster than intelligence, so it is necessary to devise ways to hold one’s patience. Sports and meditation (like Vipassana) are ways to work on this trait.
Trait 2: Resilience
One has to hold on and keep going. Failures are part of the journey. As famously quoted in the movie Rocky (played by Sylvester Stallone): ‘It’s not about how hard you hit. It’s about how hard you can get hit and keep moving forward. How much you can take and keep moving forward’. It takes a lot of effort to swim against the tide, and being resilient under difficult circumstances takes you a long way. One has to stand like a wall in the face of adversities.
Trait 3: Cut the Noise
The ability to turn deaf ears to peoples’ opinions is crucial if you are planning to take unknown paths. You don’t plan your career based on what your neighbour thinks about you. There are opportunities beyond the populistic mainstream opinions. So value your own plans and have the courage to follow your dreams.
Where do you work now? What problems do you solve?
At the moment I am working at the University of Sherbrooke in Quebec, Canada. The fundamental part of my job is to develop algorithms to extract information from satellite images. A typical day at my job can range from working on mathematical relationships based on the physics of image formation to writing technical articles to communicate my research outcomes. A lot of time is spent on reading the past literature to figure out research gaps.
Some algorithms are at the research stage while some are operational. For example, in the agricultural context, such techniques are used to determine the risk of crop failures or the approximate yield of production. It takes a lot of R&D and validation to put a technique for operational use, since crucial decisions are based on their outcomes.
What are the skills needed in your role? How did you acquire them?
Critical thinking and approaching a problem from scratch are some of the fundamental skills required for my job. One also needs a sound understanding of physics, mathematics, and computer science. It’s an interdisciplinary field.
What I love about my job is the ability to plan my own course of action. As a researcher, you are never out of ideas. It’s like running your own business. I seldom take a weekend off. I am not working on a set of instructions put in front of me stuffed in a file. I am the one who creates that file. Apart from this, I am also responsible for lecturing and mentoring students.
How does your work benefit society?
The government spends billions of dollars of taxpayers’ money to support R&D at academic and government institutions. Such investments in R&D
support government decisions at international levels through influence on geopolitics and economics.
Tell us an example of a specific memorable work you did that is very close to you!
In 2021, a huge avalanche caused havoc in the Indian Himalayas. I was working at the French Space Agency (CESBIO) at that time. Within a matter of a week, we put together a team of more than 50 scientists from around the world to explain the cause of this disastrous event. Our work was published in the coveted Science magazine and was covered by international media houses like the BBC.
Your advice to students based on your experience?
As Steve Jobs rightly quoted: ‘Have the courage to follow your heart and intuition. They somehow know what you truly want to become’
So listen to your intuition and have a dream that you can wake up to every morning. And as the celebrated Olympian Michael Phelps quotes: ‘You can’t put a limit on anything. The more you dream, the farther you get’
My future research will focus on expanding the branches of my interdisciplinary collaborations since I believe that the opportunity for innovation lies at the intersection of domains. I would like to be involved in a healthy mix of both the development and application of Earth observation algorithms. There is a perpetual trend in the Earth observation community to push just another algorithm in the presence of a bunch of existing ones by merely demonstrating marginal improvements. Redundancy is something I would like to consciously avoid and rather focus on exploiting the strengths of the existing techniques to address the societal and industry requirements. Furthermore, I have seldom planned things in my life. I will grab suitable opportunities that come my way and be the same happy-go-lucky person.