EO Detective ID SW6-2303-EVT-DEC15
What do you work on?
Over the past few years I have worked with international agencies on early warning systems that help address food shortages. We assess risk to droughts and floods, which affect food production and availability, and link this to socio-economic factors that determine food accessibility such as household vulnerabilities and food prices. Under a changing climate, it is equally important for farmers to be able to grow crops and for international organisations to be able to respond by sending food aid where and when it is most urgently needed. I find it fascinating to work on making such responses more cost effective and efficient.
The pictures are from a field trip in Tunisia. We made ground observations of landscape, vegetation, water sources and soil salinisation, and learned about traditional rainwater irrigation systems. I then developed a computer-based model of water balance in these areas using Earth observation data.
How did you come to be an EO Detective?
My job in aerial imaging the summer before I finished my bachelor’s degree in environmental sciences inspired me to learn more about digital cameras flown on small aircraft and, later, about imaging instruments on space-borne platforms (satellites). I then continued my studies in post-graduate school and years later, after graduating with a PhD and working as a research scientist, I still think it was this early hands-on experience in that enthused me to learn more about Earth observation applications and eventually pursue a career in the area.
What do the images show?
The images show rainfall over Tanzania for the same time period (21–30 April 2011) mapped by three different rainfall products (ARC, CHIRPS, and TAMSAT). You can see substantial differences, both in terms of the amount of rainfall (up to almost 300 mm in ARC2, and less than 200 mm in CHIRPS and TAMSAT) and in how it is spread across the country.
Rainfall is one of the key factors affecting crop growth. Therefore, when we use the rainfall products in a computer-based model of crop growth and development to estimate seasonal production of, in this case, maize, the results would be affected by these differences. It is thus important to validate satellite-based rainfall data by comparing it with ground-based observations. By understanding the impact of these differences on the estimates we make of crop growth, we can better understand what impact the future climate may have on crop production in the region.
How is the data you use collected?
The data I use are collected by generations of geostationary satellites (fixed over a given location on the Earth) and polar orbiting satellites. Information from many of these is combined to make data products such as those which generated the rainfall images.
What’s the best thing about your job?
I enjoy working with colleagues from across the world, from different fields, and decision-makers in government, private, and non-profit sectors that wish to make use of EO data and science. As a research scientist, I also appreciate the opportunity to retreat from team and collaborative work occasionally and to focus on investigating a specific issue in depth, to write code to analyse data, or to read or peer-review articles for academic journals.
I know that clouds can be as low as a few hundred metres above ground, yet I was surprised to wake up ‘above the clouds’ on Kilimanjaro – a sight not to be forgotten!
Tell us about your favourite image of the Earth from space
I appreciate the great variety of images of the Earth taken by astronauts and satellites, but also those from low-flying platforms such as hot-air balloons and unmanned aerial vehicles, or UAVs (also known as drones). I like the dynamics in images of clouds such as the ones we use for rainfall estimation from the EUMETSAT Meteosat satellites (shown), the ‘time travel’ option in the NASA MODIS vegetation index (NDVI) data, NASA’s ‘Blue Marble’ night lights imagery, and the ESA image of space debris around the Earth, even though the size of the satellites is exaggerated.
What do you do in your spare time?
Reading books, visiting food markets, spending time with family and friends, and taking long walks in my favourite cities. I used to photograph a lot, but now prefer to observe and capture ‘mind maps and photos’ of my environment.