A TRMM-Calibrated infrared technique for rainfall estimation: application on rain events over eastern Mediterranean

The aim is to evaluate the use of a satellite infrared (IR) technique for estimating rainfall over the eastern Mediterranean. The Convective-Stratiform Technique (CST), calibrated by coincident, physically retrieved rain rates from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), is applied over the Eastern Mediterranean for four rain events during the six month period of October 2004 to March 2005. Estimates from this technique are verified over a rain gauge network for different time scales. Results show that PR observations can be applied to improve IR-based techniques significantly in the conditions of a regional scale area by selecting adequate calibration areas and periods. They reveal, however, the limitations of infrared remote sensing techniques, originally developed for tropical areas, when applied to precipitation retrievals in mid-latitudes

An Effective Satellite Remote Sensing Tool Combining Hardware and Software Solutions

In this paper we propose a new effective remote sensing tool combining hardware and software solutions as an extension of our previous work. In greater detail the tool consists of a low cost receiver subsystem for public weather satellites and a signal and image processing module for several tasks such as signal and image enhancement, image reconstruction and cloud detection. Our solution allows to manage data from satellites effectively with low cost components and portable software solutions. We aim at sampling and processing of the modulated signal entirely in software enabled by Software Defined Radios (SDR) and CPU computational speed overcoming hardware limitation such as high receiver noise and low ADC resolution. Since we want to extend our previous method to demodulate signals coming from various meteorological satellites, we propose a new high frequency receiving system designed to receive and demodulate signals transmitted at 1.7 GHz. The signals coming from satellites are demodulated, synchronized and enhanced by using low level image processing techniques, then cloud detection is performed by using the well known K-means clustering algorithm. The hardware and software architecture extensions make our solution able to receive and demodulate high frequency and bandwidth meteorological satellite signals, such as those transmitted by NOAA POES, NOAA GOES, EUMETSAT Metop, Meteor-M and FengYun

Application of an automated cloud-tracking algorithm on satellite imgery for tracking and monitoring small mesoscale convective cloud systems

In this study, an automatic algorithm for tracking convective cloud cells, on the basis of infrared and water vapour Meteosat images, is applied in the case of intense precipitation events of 26 and 27 January 1996 in Greece, and the results are presented. The case presented in this study has the particularity of consisting of several localized maximum precipitation events that resulted from small mesoscale convective systems. The ability of the algorithm to detect and track in Meteosat images, in real mode, propagating cloud systems of this size, through the monitoring of several cloud parameters that express cloud development and movement, is examined. It was found that the algorithm was capable of identifying small mesoscale cloud cells and tracking them consistently to the point of dissipation. Moreover, the introduction in the algorithm of new cloud parameters, which are directly related to the cloud-top structure, has proved very valuable in providing additional information on the convective potential of the detected cloud cells. Finally, an empirical nowcasting of convective cloud movement and evolution could be carried out in many cases to support the forecaster's decisions by using information on cloud speed, direction and development in conjunction with synoptic analysis. © 2005 Taylor & Francis Group Ltd

Categorization of meteorological parameters and systems in support of the assessment of the dispersion of forest fire related air emissions

The dispersion of fire related air emissions depends greatly on the meteorological parameters and systems which influence the weather conditions at the site of interest. In this study, an interpretation of the physical meaning of the meteorological parameters at the surface, in the upper air and in relation to synoptic conditions is provided in an effort to assess the dispersion patterns of forest fire related air emissions. In particular a variety of meteorological parameters as temperature, humidity, pressure and others, in the fire area, are categorized to describe the prevailing conditions at the site of interest depending on the type of the front (warm, cold, occluded) and the time evolution of the front, the latter as relating to the site of interest (approaching, over the site, leaving the site). Such categorizations may be used in Decision Support Systems for forest fire management

Categorization of meteorological parameters and systems in support of the assessment of the dispersion of forest fire related air emissions

The dispersion of fire related air emissions depends greatly on the meteorological parameters and systems which influence the weather conditions at the site of interest. In this study, an interpretation of the physical meaning of the meteorological parameters at the surface, in the upper air and in relation to synoptic conditions is provided in an effort to assess the dispersion patterns of forest fire related air emissions. In particular a variety of meteorological parameters as temperature, humidity, pressure and others, in the fire area, are categorized to describe the prevailing conditions at the site of interest depending on the type of the front (warm, cold, occluded) and the time evolution of the front, the latter as relating to the site of interest (approaching, over the site, leaving the site). Such categorizations may be used in Decision Support Systems for forest fire management

The impact of air pollution in an urban area on the amount of solar ultraviolet radiation at the surface

Measured and calculated values of solar ultraviolet radiation (SUVR) at the surface in the Athens area show significant negative correlation between the SUVR values and the level of ozone. This negative correlation supports the hypothesis that increased levels of ozone in the lower troposphere may protect the surface from harmful SUVR. This correlation can be expressed statistically which implies that the influence of photochemical pollution to the transfer of SUVR within the lower troposphere, may be predicted from ground based measurements of air quality. © 1992, Taylor & Francis Group, LLC. All rights reserved

The impact of air pollution in an urban area on the amount of solar ultraviolet radiation at the surface

Measured and calculated values of solar ultraviolet radiation (SUVR) at the surface in the Athens area show significant negative correlation between the SUVR values and the level of ozone. This negative correlation supports the hypothesis that increased levels of ozone in the lower troposphere may protect the surface from harmful SUVR. This correlation can be expressed statistically which implies that the influence of photochemical pollution to the transfer of SUVR within the lower troposphere, may be predicted from ground based measurements of air quality. © 1992, Taylor & Francis Group, LLC. All rights reserved