Context

In the context of global climate change, most Mediterranean cities have undergone significant warming during last decades which is more pronounced in the summer. Urban Heat Island phenomenon has an additive effect on the regional warming. Meanwhile, the increase in the mean air temperature is accompanied by the increase in the frequency of hot extremes. Therefore, appraisal and quantification of spatially distributed heat wave risk are required to develop innovative tools and services for the subsequent design of targeted measures and strategies. This was the motivation behind the development of a fully automated system for the continuous monitoring of Land Surface and Air Temperatures (LST and AT, respectively) of European cities in real time every 5 minutes at 1km resolution.

Realizing the importance of monitoring the thermal urban environment and the existing gap in data and system availability, the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens (IAASARS/NOA) has developed a system for continuous monitoring the urban thermal environment at high spatial and temporal resolution. This work presents a system based on the data acquired by Meteosat Second Generation 2 – Spinning Enhanced Visible and Infrared Imager (MSG2-SEVIRI) Rapid Scanning Service (RSS) downscaled to 1 km. It is using several algorithms developed by our team as well as products and procedures from Eumetsat Satellite Application Facility on support to Nowcasting/ and Very Short-Range Forecasting (SAFNWC version MSG v2013). In the current implementation, Numerical Weather Predictions (NWP) necessary for SAFNWC are retrieved from the Global Forecasting System (GFS of the U.S. National Climatic Data Centre) for the entire Earth with a grid size of 0.25 degrees.

The developed system comprises five major modules, namely: i) SEVIRI image acquisition, ii) nowcasting of clouds and other atmospheric parameters, iii) derivation of LST and AT from clear sky thermal infrared radiances; iv) sharpening of LST using Support Vector Regression Machines (SVM) and iterative gradient boosting; and v) resampling of AT to 1km. For the demanding retrieval of AT, a first guess atmospheric profile is utilized from GFS and subsequently the radiances at satellite are simulated by RTTOV radiative transfer model. The solution is iterated until the simulated and measured radiances converge.

The system offers four significant advantages: 1) it exploits the high temporal resolution of SEVIRI RSS imagery (5 min), 2) it enhances the spatial resolution of the retrieved temperatures (LST and AT) down to 1 km, 3) it covers a large number of cities around the world, and 4) the derived products are available in real time.

Higher-level products are also produced at the same resolution: Heat Wave Hazard, Cooling Degrees and Discomfort indices. The system as well as the products obtained for 15 cities during summer 2015.

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Contact Person
Iphigenia Keramitsoglou
Senior Researcher
Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing
National Observatory of Athens
I. Metaxa & Vas. Pavlou St.
GR-15236, Penteli, Greece

e-mail
ik@noa.gr
phone
+30 210 810 9167
twitter
@iphigenia_k
linkedin
#ikeramit
Disclaimer

TREASURE has attempted to provide information as accurate as possible, however, all geographic information has limitations due to the scale resolution , modelling limitations, update and interpretation of the original source datasets. Accordingly, TREASURE maps are distributed as is, without any warranty, either expressed or implied, including but not limited to warranties of suitability to a particular purpose or use. The entire risk as to the results of the use of these map is assumed by the users and the Service Provider accepts no liability for any loss, damage or inconvenience caused as a result of reliance on the mapping.

TREASURE Nowcasting service is funded by DG ECHO (ECHO/SUB/2014/695561). Satellite images are provided through the ground segment infrastructure of IAASARS/NOA for acquisition of EUMETSAT Meteosat Second Generation – Spinning Enhanced Visible and Infrared Imager upgraded in the framework of the project BEYOND (FP7-REGPOT-2012-2013-1; No. 316210). Certain software components have been acquired in the framework of PROTEAS project within GSRT’s KRIPIS action, funded by Greece and the European Regional Development Fund of the European Union under the O.P. Competitiveness and Entrepreneurship, NSRF 2007-2013 and the Regional operational Program of Attica.