Real time monitoring of the diurnal variations in the distribution of the land surface temperatures (LST) across a city is significant to a range of issues, including heat wave risk, energy demand and heat-related health issues. Geostationary satellites, such as Meteosat Second Generation- Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI) viewing Europe, Africa and a part of S. America, are the only remote sensing platforms that can offer continuous monitoring of LST distribution at quarter-hourly basis. The high temporal resolution of many meteorological geostationary satellites is unparalleled for the diurnal study of the Surface Urban Heat Island (SUHI) phenomenon, since it can reveal the most subtle changes. However, their coarse spatial resolution of 3-5 km has prohibited their extensive use for urban studies. The only way to exploit the dataset from this monitoring platform for urban applications is to employ computational methods for sharpening the data down to 1 km or better.

A system for real time and online monitoring of the thermal urban environment using geostationary satellite images is being developed at the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens (IAASARS/NOA) in Greece. The system comprises separate modules, namely: satellite image acquisition, cloud screening, and sharpening of LST. Satellite images are acquired from MSG-SEVIRI EUMETCast station installed at IAASARS/NOA. The cloud screening delineates the cloud-free pixels allowing the LST derivation to be applied only to clear sky thermal infrared radiances. Lastly, LST imagery is downscaled down to 1 km spatial resolution using Support Vector Regression Machines (SVM) and iterative gradient boosting.

The summer months of 2014 were the first operational ones: our system produced thousands of sharpened LST images every quarter-hour in real time. Our vision is to develop the system for all the cities with population greater than 1 million in the SEVIRI disk (117 cities in total). The system can be potentially used for heat-related health issues, energy demand applications, urban planning, Urban Heat Island studies and more.

A short video of what we do: http://youtu.be/pCMUHi7FJiY

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Dr. Iphigenia Keramitsoglou is a Senior Researcher at IAASARS/NOA and co-Leader of the Group on Earth Observations (GEO) Global Urban Observation and Information Task. She is member of the Program Management Board of BEYOND project that is partly financing this activity.

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