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11.
Katsanos Dimitrios Retalis Adrianos Tymvios Filippos Michaelides Silas 《Natural Hazards》2016,83(1):53-74
A study of a daily precipitation database for the island of Cyprus is performed for a period of 30 years. A number of climatic indices for precipitation are calculated using the recently available CHIRPS dataset, on high spatial (0.05°) and temporal (daily) resolution. The same parameters for the same time period (1981–2010) are then calculated using the dense network of rain gauges of the Cyprus Department of Meteorology. The results show a quite promising performance regarding indices related to daily precipitation thresholds, resulting in high correlation scores. In the case of indices referring to number of days, it seems that the results are ambiguous, with medium or no correlation, probably related to the criteria used for the identification of a wet (rainy) day on the CHIRPS dataset. 相似文献
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Adrianos Retalis Nicolaos Sifakis 《ISPRS Journal of Photogrammetry and Remote Sensing》2010,65(1):17-25
Low and moderate spatial resolution satellite sensors (such as TOMS, AVHRR, SeaWiFS) have already shown their capability in tracking aerosols at a global scale. Sensors with moderate to high spatial resolution (such as MODIS and MERIS) seem also to be appropriate for aerosol retrieval at a regional scale. We investigated in this study the potential of MERIS-ENVISAT data to resolve the horizontal spatial distribution of aerosols over urban areas, such as the Athens metropolitan area, by using the differential textural analysis (DTA) code. The code was applied to a set of geo-corrected images to retrieve and map aerosol optical thickness (AOT) values relative to a reference image assumed to be clean of pollution with a homogeneous atmosphere. The comparison of satellite retrieved AOT against PM10 data measured at ground level showed a high positive correlation particularly for the AOT values calculated using the 5th MERIS’ spectral band (R2=0.83). These first results suggest that the application of the DTA code on cloud free areas of MERIS images can be used to provide AOT related to air quality in this urban region. The accuracy of retrieved AOT mainly depends on the overall quality, the pollution cleanness and the atmospheric homogeneity of the reference image. 相似文献
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Dimitris A. Retalis 《Pure and Applied Geophysics》1987,125(4):669-678
In the present study the variation in small ion concentration (SIC), positive and negative, above Athens (=37°58.3N, =23°43E,h=107 m) after Chernobyl reactor accident is examined.SIC started to increase importantly at the National Observatory of Athens (N.O.A) since 3 May 1986 and reached its highest mean daily values on Monday, 5 May. These maximum values were 4 times the normal for positive ions and 5 times the normal for negative ions. Correlation coefficients were calculated between SIC and radionuclides I-131, Cs-137, Ru-103 and outdoor exposure rate. 相似文献
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