Robust Satellite Data Analysis Technique Research Articles

Outgoing longwave radiation anomalies analysis associated with different types of seismic activity

The paper has developed and proposed a statistical analysis method based on the Robust Satellite data analysis technique to detect seismic anomalies within the NOAA OLR dataset based on spatial/temporal continuity analysis. The proposed methods has been applied to statistical analyze about 3376 earthquake cases from September 01, 2007 to May 23, 2015. For statistical purposes, all these events have been divided into different types on the basis of the seismic parameters, including Southern or Northern Hemisphere earthquakes, earthquakes at different magnitude levels, earthquakes at different depth levels. The results show that the intensity of the anomalies increased with the magnitude increasing; anomalies are more easily observed during shallow earthquakes than the deep ones; more obvious anomalies could be detected for the earthquakes occurring in the Northern Hemisphere and the anomalies significant increases near the epicenter one day before and on the day of the earthquake. A similar anomaly shows that there are anomalies near the epicenters before earthquakes and the anomalies have some relation with the earthquake preparation on all seismic activity. All these statistical results can help create a better understanding of the preparation process of the earthquakes.

Seismic infrared anomalies detection in the case of the Wenchuan earthquake using bi-angular advanced along-track scanning radiometer data

<p>The paper has developed Robust Satellite data analysis Technique (RST) to detect seismic anomalies in the case of the Wenchuan earthquake occurred on May 12, 2008, using the bi-angular Advanced Along-Track Scanning Radiometer (AATSR) gridded brightness temperature (BT) data based on spatial/temporal continuity and confutation analysis. The proposed method has been applied to analyze the Wenchuan earthquake with longitude from 95°E to 111°E and latitude from 23°N to 39°N, and a full data-set of 7 years data from 2003 to 2009 during the months of April and May has been analyzed. Combining with the rupture structure data of the Wenchuan earthquake, the analyzed results indicate that: the main structure activity (the Yingxiu-Beichuan fault) characteristics of the Wenchuan earthquake can be identified and extracted using the bi-angular AATSR nadir and forward brightness temperature data, and the seismic infrared radiation anomalies detected by the AATSR nadir brightness temperature is more close to the Yingxiu-Beichuan fault.</p>

Satellite detection of IR precursors using bi-angular advanced along-track scanning radiometer data: a case study of Yushu earthquake

The paper has developed and proposed a synthesis analysis method based on the robust satellite data analysis technique (RST) to detect seismic anomalies within the bi-angular advanced along-track scanning radiometer (AATSR) gridded brightness temperature (BT) data based on spatial/temporal continuity analysis. The proposed methods have been applied to analyze the Yushu (Qinghai, China) earthquake occurred on 14th April 2010, and a full AATSR data-set of 8 years data from March 2003 to May 2010 with longitude from 91°E to 101°E and latitude from 28°N to 38°N has been analyzed. Combining with the tectonic explanation of spatial and temporal continuity of the abnormal phenomena, the analyzed results indicate that the infrared radiation anomalies detected by the AATSR BT data with nadir view appear and enhance gradually along with the development and occurring of the earthquake, especially along the Ganzi-Yushu fault, Nu River fault and Jiali-Chayu fault; more infrared anomalies along the earthquake fault zone (Lancangjiang fault and Ning Karma Monastery-Deqin fault) are detected using the proposed synthesis analysis method, which can also characterize the activity of seismic faults more precisely.

Reducing atmospheric noise in RST analysis of TIR satellite radiances for earthquakes prone areas satellite monitoring

Space–time fluctuations of the Earth’s emitted Thermal Infrared (TIR) radiation observed from satellite from months to weeks before an earthquake are reported in several studies. Among the others, a Robust Satellite data analysis Technique (RST) was proposed (and applied to different satellite sensors in various geo-tectonic contexts) to discriminate anomalous signal transients possibly associated with earthquake occurrence from normal TIR signal fluctuations due to other possible causes (e.g. solar diurnal–annual cycle, meteorological conditions, changes in observational conditions, etc.). Variations in satellite view angle depending on satellite’s passages (for polar satellites) and atmospheric water vapour fluctuations were recognized in the past as the main factors affecting the residual signal variability reducing the overall Signal-to-Noise (S/N) ratio and the potential of the RST-based approach in identifying seismically related thermal anomalies. In this paper we focus on both factors for the first time, applying the RST approach to geostationary satellites (which guarantees stable view angles) and using Land Surface Temperature (LST) data products (which are less affected by atmospheric water vapour variability) instead of just TIR radiances at the sensor.The first results, obtained in the case of the Abruzzo earthquake (6 April 2009, MW∼6.3) by analyzing 6years of SEVIRI (Spinning Enhanced Visible and Infrared Imager on board the geostationary Meteosat Second Generation satellite) LST products provided by EUMETSAT, seem to confirm the major sensitivity of the proposed approach in detecting perturbations of the Earth’s thermal emission a few days before the main shock. The results achieved in terms of increased S/N ratio (in validation) and reduced “false alarms” rate (in confutation) are discussed comparing results obtained by applying RST to LST products with those achieved by applying an identical RST analysis (using the same MSG-SEVIRI 2005–2010 data-set) to the simple TIR radiances at the sensor.

Detecting seismic IR anomalies in bi-angular Advanced Along-Track Scanning Radiometer data

Abstract. This paper presents a validation and confutation analysis using the methods of the robust satellite data analysis technique (RST) to detect seismic anomalies within the bi-angular Advanced Along-Track Scanning Radiometer (AATSR) data based on spatial/temporal continuity analysis. The distinguishing feature of our method is that we carried out a comparative analysis of seismic anomalies from bi-directional observation, which could help understanding seismic thermal infrared (TIR) anomalies. The proposed method has been applied to analyse bi-angular AATSR gridded brightness temperature data with longitude from 5 to 25° E and latitude from 35 to 50° N associated with the earthquake that occurred in Abruzzo, Italy, on 6 April 2009, and a full data set of 7 yr data from 2003 to 2009 during the months of March and April has been analysed for validation purposes. Unperturbed periods (March–April 2008) have been considered for confutation analysis. Combining with the tectonic explanation of spatial and temporal continuity of the abnormal phenomena, along with the analysed results, a number of anomalies could be associated with possible seismic activities, which follow the same time and space. Therefore, we conclude that the anomalies observed from 29 March 2009 to 5 April 2009, about eight days before the Abruzzo earthquake, could be earthquake anomalies.

A New Approach for Detecting and Monitoring Saharan Dusts from Space

A New Approach for Detecting and Monitoring Saharan Dusts from Space The Saharan region has long been indicated as the main source in the world of soil dust in the atmosphere. Saharan dust storms are particularly investigated because they represent a potential risk for human health and cause damages and disruptions to the transport routes and communication. They can have direct implications (strictly related to the desertification processes affecting the Sub Saharan region) on the Earth’s climatic system and/or on the precipitation regimes. In recent years, in addition to the ground monitoring systems, several satellite techniques have been proposed to detect and monitor Saharan dust clouds. The success of these methodologies, as those exploiting the reverse absorption behaviour shown by silicate particles, in comparison with ice crystals and water droplets, at 11 and 12 μm wavelengths (split-window), is strongly dependent on the observational conditions (day/night, land/sea, etc.) and on the specific aerosol properties (mainly size distribution and complex refractive index). In particular, although dust and meteorological clouds generally show a different spectral behaviour in the split window bands, an effective discrimination of these features still represent a major issue. In this paper, a Robust Satellite data analysis Technique (RST), which already highlighted good performances in detecting desert dust aerosol, has been further tested, analyzing an important Saharan dust event affecting Mediterranean basin in May 2010, with results compared to those provided by two traditional split window methods. Outcomes of this study, achieved using, for the first time, daytime infrared MSG-SEVIRI (Meteosat Second Generation-Spinning Enhanced Visible and Infra-red Imager) data, confirm that RST, thanks to a good trade-off between sensitivity and reliability of detection, may profitably be used for monitoring Saharan dust events from space in different observational conditions.

A robust satellite technique for monitoring seismically active areas: The case of Bhuj–Gujarat earthquake

A robust satellite data analysis technique (RAT) has been recently proposed as a suitable tool for satellite TIR surveys in seismically active regions and already successfully tested in different cases of earthquakes (both high and medium–low magnitudes). In this paper, the efficiency and the potentialities of the RAT technique have been tested even when it is applied to a wide area with extremely variable topography, land coverage and climatic characteristics (the whole Indian subcontinent). Bhuj–Gujarat's earthquake (occurred on 26th January 2001, M S ∼ 7.9) has been considered as a test case in the validation phase, while a relatively unperturbed period (no earthquakes with M S ≥ 5, in the same region and in the same period) has been analyzed for confutation purposes. To this aim, 6 years of Meteosat-5 TIR observations have been processed for the characterization of the TIR signal behaviour at each specific observation time and location. The anomalous TIR values, detected by RAT, have been evaluated in terms of time–space persistence in order to establish the existence of actually significant anomalous transients. The results indicate that the studied area was affected by significant positive thermal anomalies which were identified, at different intensity levels, not far from the Gujarat coast (since 15th January, but with a clearer evidence on 22nd January) and near the epicentral area (mainly on 21st January). On 25th January (1 day before Gujarat's earthquake) significant TIR anomalies appear on the Northern Indian subcontinent, showing a remarkable coincidence with the principal tectonic lineaments of the region (thrust Himalayan boundary). On the other hand, the results of the confutation analysis indicate that no meaningful TIR anomalies appear in the absence of seismic events with M S ≥ 5.

Assessing the potential of thermal infrared satellite surveys for monitoring seismically active areas: The case of Kocaeli (İzmit) earthquake, August 17, 1999

Space–time anomalies of Earth's emitted radiation in the thermal infrared spectral range (TIR) measured from satellite months to weeks before the occurrence of earthquakes, have been interpreted, by several authors, as pre-seismic signals. The claimed connection of TIR emission with seismic activity has been considered, up to now, with some caution by the scientific community mainly for the insufficiency of the validation data-sets and the scarce importance attached by those authors to other causes (e.g. meteorological) that, rather than seismic activity, could be responsible for the observed TIR signal fluctuations. In this paper, a robust satellite data analysis technique is described which permits us to identify anomalous space–time TIR signal transients even in very variable observational (satellite view angle, land topography and coverage, etc.) and natural (e.g. meteorological) conditions. A statistically well-founded definition of TIR anomaly is given and proposed as a suitable tool for satellite TIR surveys in seismically active regions. Eight years of Meteosat TIR observations have been analyzed in order to characterize the TIR signal behavior at each specific observation time and location. Space–time TIR signal transients have then been analyzed, both in the presence ( validation) and in the absence of ( confutation) seismic events, looking for possible space–time relationships. The devastating earthquake which occurred in Turkey (İzmit, August 17, M S∼7.8) in 1999 has been considered as a test case for validation, relatively unperturbed periods (no earthquakes with M > 5) were taken for confutation purposes. Quite intense ( S / N > 3.5) and rare, spatially extensive and time persistent, TIR signal transients were identified appearing eight days before the İzmit main shock in Greece, moving to Turkey on August 13 and disappearing, moving back to Greece, some days after. Possible implications of such results, together with present limitations of the proposed technique, will also be discussed in the light of the improved performances expected by its extension to other existing or future satellite packages.

Seismically active area monitoring by robust TIR satellite techniques: a sensitivity analysis on low magnitude earthquakes in Greece and Turkey

Abstract. Space-time TIR anomalies, observed from months to weeks before earthquake occurrence, have been suggested by several authors as pre-seismic signals. Up to now, such a claimed connection of TIR emission with seismic activity has been considered with some caution by scientific community mainly for the insufficiency of the validation data-sets and the scarce importance attached by those authors to other causes (e.g. meteorological) that, rather than seismic activity, could be responsible for the observed TIR signal fluctuations. A robust satellite data analysis technique (RAT) has been recently proposed which, thanks to a well-founded definition of TIR anomaly, seems to be able to identify anomalous space-time TIR signal transients even in very variable observational (satellite view angle, land topography and coverage, etc.) and natural (e.g. meteorological) conditions. Its possible application to satellite TIR surveys in seismically active regions has been already tested in the case of several earthquakes (Irpinia: 23 November 1980, Athens: 7 September 1999, Izmit: 17 August 1999) of magnitude higher than 5.5 by using a validation/confutation approach, devoted to verify the presence/absence of anomalous space-time TIR transients in the presence/absence of seismic activity. In these cases, a magnitude threshold (generally M<5) was arbitrarily chosen in order to identify seismically unperturbed periods for confutation purposes. In this work, 9 medium-low magnitude (4<Mb<5.5) earthquakes which occurred in Greece and Turkey have been analyzed in order to verify if, even in these cases, anomalous TIR transients can be observed. The analysis, which was performed using 8 years of Meteosat TIR observations, demonstrated that anomalous TIR transients can be observed even in the presence of medium-low magnitude earthquakes (4<Mb<5.5). As far as the research (just started) of possible correlation among TIR anomalies and earthquake occurrence is concerned, such a result suggests that: a) in order to identify seismically unperturbed periods for confutation purposes, a magnitude threshold (at least) lower than 4 should be used; b) the proposed validation/confutation approach should be applied in low-seismicity areas in order to find suitably long seismically quiescent periods.