Giovanni Laneve

Validation of Aura Microwave Limb Sounder Ozone by ozonesonde and lidar measurements

We present validation studies of MLS version 2.2 upper tropospheric and stratospheric ozone profiles using ozonesonde and lidar data as well as climatological data. Ozone measurements from over 60 ozonesonde stations worldwide and three lidar stations are compared with coincident MLS data. The MLS ozone stratospheric data between 150 and 3 hPa agree well with ozonesonde measurements, within 8% for the global average. MLS values at 215 hPa are biased high compared to ozonesondes by A`20% at middle to high latitude, although there is a lot of variability in this altitude region. Comparisons between MLS and ground-based lidar measurements from Mauna Loa, Hawaii, from the Table Mountain Facility, California, and from the Observatoire de Haute-Provence, France, give very good agreement, within A`5%, for the stratospheric values. The comparisons between MLS and the Table Mountain Facility tropospheric ozone lidar show that MLS data are biased high by A`30% at 215 hPa, consistent with that indicated by the ozonesonde data. We obtain better global average agreement between MLS and ozonesonde partial column values down to 215 hPa, although the average MLS values at low to middle latitudes are higher than the ozonesonde values by up to a few percent. MLS v2.2 ozone data agree better than the MLS v1.5 data with ozonesonde and lidar measurements. MLS tropical data show the wave one longitudinal pattern in the upper troposphere, with similarities to the average distribution from ozonesondes. High upper tropospheric ozone values are also observed by MLS in the tropical Pacific from June to November.

Remote sensing water observation for supporting Lake Victoria weed management.

This paper aims to assess the suitability of remote sensing for enhancing the management of water body resources and for providing an inexpensive way to gather, on a wide area, weed infestation extent and optical parameter linked to the water body status. Remotely sensed satellite images and ancillary ground true data were used to produce land cover maps, trough classification techniques, and water compounds maps, applying radiative transfer models. The study proposed within the framework of the cooperation between Italian Foreign Affair Ministry (through the University of Rome) and Kenyan Authorities has been carried out on the Kenyan part of the Lake Victoria. This lake is one of the largest freshwater bodies of the world where, over the last few years environmental challenges and human impact have perturbed the ecological balance affecting the biodiversity. The objective of this research study is to define the thematic products, retrievable from satellite images, like weed abundance maps and water compound concentrations. These products, if provided with an appropriate time frequency, are useful to identify the preconditions for the occurrence of hazard events like abnormal macrophyte proliferation and to develop an up-to-date decision support system devoted to an apprised territory, environment and resource management.

satellite de-orbiting by means of electrodynamic tethers part i: general concepts and requirements

Abstract It has been recently suggested that conductive tethers, besides other applications, may be effective for the de-orbiting of satellites at the end of their operational life. In this paper we give a preliminary evaluation of this capability with respect to a well-defined tether system and using the expertise and results from the recently flown TSS-1 project. The system considered is a long conducting tether, covered by an insulator, with a passive electron collector at the positive termination and a hollow-cathode electron emitter at the opposite end. In analyzing this system, we point out the crucial importance of the contact impedances associated to the coupling between the tether terminations and the ionospheric plasma. We give a first evaluation of the de-orbiting time for a typical case and conclude about feasibility of a tether system to de-orbit satellites.

Continuous Monitoring of Forest Fires in the Mediterranean Area Using MSG

Fires represent one of the main factors of degradation and destruction of the Mediterranean forest heritage. According to fire-fighting agencies, a satellite-based fire-detection system can be considered operationally useful for Mediterranean countries when fires with a minimum extent of 1500 m2 can be detected with a temporal resolution of 30 min. In fact, such a system should be able to detect fires at their first stage when it is possible to extinguish them more easily. The Centro di Ricerca Progetto San Marco has been analyzing for several years the possibility of using images acquired by the Spinning Enhanced Visible and Infrared Imager sensor onboard the geostationary satellite Meteosat Second Generation for this purpose. A new processing approach exploiting the increase in both spatial and temporal resolution (15 min) with respect to previous meteosat systems is described in this paper. The idea is based on the use of a change-detection technique to maximize the detection capabilities of the system in spite of its limited spatial resolution. This technique consists of comparing two or more images acquired at 15-min intervals, for which any temperature change can be attributed to fast dynamic phenomena, such as fires, when natural changes are modeled and removed. An assessment of the performances of this algorithm is carried out comparing its results with the report made available by Italian fire-fighting agencies and with fire products based on higher resolution sensors such as the Moderate Resolution Imaging Spectroradiometer

Assessment of the abnormal growth of floating macrophytes in Winam Gulf (Kenya) by using MODIS imagery time series

Abstract The objective of this research study is to assess the capability of time-series of MODIS imagery to provide information suitable for enhancing the understanding of the temporal cycles shown by the abnormal growth of the floating macrophytes in order to support monitoring and management action of Lake Victoria water resources. The proliferation of invasive plants and aquatic weeds is of growing concern. Starting from 1989, Lake Victoria has been interested by the high infestation of water hyacinth with significant socio-economic impact on riparian populations. In this paper, we describe an approach based on the time-series of MODIS to derive the temporal behaviour, the abundance and distribution of the floating macrophytes in the Winam Gulf (Kenyan portion of the Lake Victoria) and its possible links to the concentrations of the main water constituencies. To this end, we consider the NDVI values computed from the MODIS imagery time-series from 2000 to 2009 to identify the floating macrophytes cover and an appropriate bio-optical model to retrieve, by means of an inverse procedure, the concentrations of chlorophyll a, coloured dissolved organic matter and total suspended solid. The maps of the floating vegetation based on the NDVI values allow us to assess the spatial and temporal dynamics of the weeds with high time resolution. A floating vegetation index (FVI) has been introduced for describing the weeds pollution level. The results of the analysis show a consistent temporal relation between the water constituent concentrations within the Winam Gulf and the FVI, especially in the proximity of the greatest proliferation of floating vegetation in the last 10 years that occurred between the second half of 2006 and the first half of 2007.The adopted approach will be useful to implement an automatic system for monitoring and predicting the floating macrophytes proliferation in Lake Victoria.

SEVIRI Onboard Meteosat Second Generation, and the Quantitative Monitoring of Effusive Volcanoes in Europe and Africa

The spectral and radiometric performance of payload SEVIRI onboard the geostationary platform MSG-2, make its data particularly well suited not only to the detection of the onset of volcanic activity, but also to the measurement of thermal radiant fluxes and eruption rates. Thorough testing was carried out on two volcanoes - Stromboli (Aeolian Islands, Southern Italy) and Piton de la Fournaise (Reunion Island, northwestern Indian Ocean) - that mostly give rise to short-lived lava flows. Aimed to comply with the outstandingly high acquisition rate, we developed an ad-hoc code to automatically detect volcanic hot-spots, measure radiant fluxes, and derive lava volume effusion rates within the 15-minute interval between two SEVIRI data streams.

Development of algorithms and products for supporting the Italian hyperspectral PRISMA mission: The SAP4PRISMA project

The SAP4PRISMA is a four year research project which aims at developing algorithms and products for the future PRISMA mission. The project started on May 2010 and is now entering his full activities as the ”PRISMA like” data set has been defined and the test areas were selected. The paper describes the main project objectives and the activities realized in the first 9 months of the project.

Improved MSG-SEVIRI Images Cloud Masking and Evaluation of its Impact on the Fire Detection Methods

One of the most important factors responsible of the fire-detection algorithms fail is represented by the inaccurate cloud detection methods. In fact, the cloud-contaminated pixels are often associated with false fire pixel because of the brightness temperature increase in the mid-infrared channel. On the other hand an incorrect cloud masking could hide a real fire pixel, especially at the borders of clouds. Together with the SEVIRI images EUMETSAT provides its own cloud mask (CLM product). This mask is computed by making full use of the MSG-SEVIRI spectral channels. Among the 12 channels, only channels 8 (IR 9.7) and 12 (HRV) are not included in the cloud detection and analysis. Due to the particular application for which CRPSM is using SEVIRI images, detection of fire at its early stage (sizes lower than 0.1 ha), a high sensitivity to changes in the radiance measured by the sensor in channel 4 (3.9 iquestm) is required. Since the presence of a cloud covering only a fraction of the pixel (~4 times 4 km at mid latitude) can produce an increase in the estimated brightness temperature, in such channel, capable to provoke a false alarm we decided to use also channel 12 in the cloud detection algorithm. Thus, in order to improve the cloud masks provided by EUMETSAT a new methodology has been introduced. The approach is firstly based on the application of the HRV channel during daytime.

Assessment of the Fire Detection Limit using SEVIRI/MSG Sensor

Forest fires represent the main cause of forest degradation in Italy and in the Mediterranean area countries. This phenomenon, progressively increasing, reached an average of 11000 fires per year in the period 1990-2000 with the destruction of 553,000 ha of vegetated areas in the Italian peninsula. It has high relevance also for other countries in the region such as Spain, Portugal, Greece, France. Damages caused by forest fires have a direct economic impact related to the cost of burned wood, and the cost of the activities of prevention, fire- fighting and recover of burned areas. Less easy is the estimate of the economic impact of forest loss as part of the eco-system (reduction of the hydro-geological defenses, spoiling of tourist and landscape attractions, etc.). An efficient way to manage this problem involves an observation system able to provide a prompt detection and monitoring of fires and a synoptic view of the area of interest. Thus, satellites seem to be the ideal instrument for this purpose, even if the temporal frequency of the observations is generally still a problem. In several previous paper the capability of setting up an early fire detection system using the sensor SEVIRI (Spinning Enhanced Visible and Infrared Imager) on board of the geostationary satellite MSG (Meteosat Second Generation) has been demonstrated. The present paper aims at assessing the limits of the SEVIRI sensor in detecting fires taking into account the spatial resolution of this sensor and the new algorithms especially developed to exploit its temporal resolution characteristics. The assessment of the limits of this sensor performances will be obtained mainly comparing its results with those obtainable from higher resolution sun- synchronous sensor data (MODIS and ASTER).

Operational Integration of Spaceborne Measurements of Lava Discharge Rates and Sulfur Dioxide Concentrations for Global Volcano Monitoring

We present the rationale and the main initial achievements of the operational prototype of the first multi-method system for the real-time, unsupervised, quantitative monitoring of erupted masses simultaneously at all active volcanoes in Europe, Africa, the Eastern Antilles and the ocean islands. The system is structured as a multi-pole, geographically distributed system, where raw datasets from space payloads SEVIRI, MODIS, GOME-2, IASI and OMI are acquired at four downlink stations, distributed to, and automatically processed at six locations in four European nations, then returned to a central post-processor for real-time alert and Wide Area Network display. This architecture is aimed at optimizing quality and timeliness of the advanced methods run within it, and to let the inherent technical knowledge remain with inventors without concern for individual intellectual property. Before entering operations early in 2012, the system underwent extensive testing in 2011 during the major eruptions of Nabro (Eritrea) and Nyamulagira (DR Congo), which are presented here.