Comparing microphysical/dynamical outputs by different cloud resolving models: impact on passive microwave precipitation retrieval from satellite

International audienceMesoscale cloud resolving models (CRM's) are often utilized to generate consistent descriptions of the microphysical structure of precipitating clouds, which are then used by physically-based algorithms for retrieving precipitation from satellite-borne microwave radiometers. However, in principle, the simulated upwelling brightness temperatures (TB's) and derived precipitation retrievals generated by means of different CRM's with different microphysical assumptions, may be significantly different even when the models simulate well the storm dynamical and rainfall characteristics. In this paper, we investigate this issue for two well-known models having different treatment of the bulk microphysics, i.e. the UW-NMS and the MM5. To this end, the models are used to simulate the same 24-26 November 2002 flood-producing storm over northern Italy. The model outputs that best reproduce the structure of the storm, as it was observed by the Advanced Microwave Scanning Radiometer (AMSR) onboard the EOS-Aqua satellite, have been used in order to compute the upwelling TB's. Then, these TB's have been utilized for retrieving the precipitation fields from the AMSR observations. Finally, these results are compared in order to provide an indication of the CRM-effect on precipitation retrieval

On the potential of sub-mm passive MW observations from geostationary satellites to retrieve heavy precipitation over the Mediterranean Area

International audienceThe general interest in the potential use of the mm and sub-mm frequencies up to 425 GHz resolution from geostationary orbit is increasing due to the fact that the frequent time sampling and the comparable spatial resolution relative to the "classical" (?89 GHz) microwave frequencies would allow the monitoring of precipitating intense events for the assimilation of rain in now-casting weather prediction models. In this paper, we use the simulation of a heavy precipitating event in front of the coast of Crete island (Greece) performed by the University of Wisconsin - Non-hydrostatic Modeling System (UW-NMS) cloud resolving model in conjunction with a 3D-adjusted plane parallel radiative transfer model to simulate the upwelling brightness temperatures (TB's) at mm and sub-mm frequencies. To study the potential use of high frequencies, we first analyze the relationships of the simulated TB's with the microphysical properties of the UW-NMS simulated precipitating clouds, and then explore the capability of a Bayesian algorithm for the retrieval of surface rain rate, rain and ice water paths at such frequencies

A preliminary comparison of Continuous Compaction Control and Portable FWD systems for Qc/Qa

Qc/Qa approach to pavement construction requires that correlated methods of measurement can be employed either by the contractors - guaranteeing the work reliability - and the controller. The case of bearing capacity evaluation for subgrade and foundation layers is today moving from traditional testing (PLT), through Portable FWDs and FWDs, to the latest version of CCC and IC systems. Most of the modern vibrating compactors can be geared with in-built testing devices able to evaluate the stiffness level of the compacted layer down to a decimetric span, during compaction. On the other hand, Portable FWDs can quickly define a dense pattern of measurements in order to assess if the surface stiffness complies with requirements. This paper presents a preliminary testing campaign, aiming to contribute to the discussion of researchers for the CCC and PFWD systems integration as cross validation methods. A full scale double trial site have been constructed and monitored with a common IC-CCC drum and two different PFWDs. Results are also presented in the form of spatial geostatistic analysis

Comparing Light Weight Deflectometers to standardize their use in the compaction control

Along with the increase of road traffic and loads, arises the need for a methodology for studying and predicting the rutting resistance of asphalt concretes. The growth of this phenomenon on the asphalt pavement is directly connected with the layers\u2019 structural damage and it is reflected in terms of safe riding. An accurate laboratory characterization of the material rutting performance is desirable, aiming to reduce the distresses during its lifetime and to predict the mixture tendency to develop excessive permanent deformations under repeated heavy traffic loading. This paper reports a case study concerning the evaluation of the mechanical characteristics of two Warm Mix Asphalts (WMA). A unique binder type was adopted to reduce the number of variables, since it is known that one of the primary cause which engender the rut distress is the plastic behavior of the binder. These analysis were carried out with different tests setup complying with the EN 12697-25 requirements, varying stress level, but keeping constant temperature, loading type and time

In situ Characterization of Self-cementing Properties of Recycled Materials

In the last years, the emerging environmental & financial issues has led the international scientific community to spend more and more research efforts on the use of recycled materials in road construction, encouraging the standardization committees to modify their references. In some Countries the re-use of construction materials is becoming mandatory, reaching high percentages of recycling materials overall the aggregates used in road constructions. In this context the release of specifications, based on in situ performance criteria, assumes greater importance enabling the widespread use of secondary raw materials. The saving up due to the use of recycled materials covers both the economic aspects (reduced supply of virgin materials) and the environmental ones (lower quarrying of inert material and less dumping of waste materials) related to the infrastructure works. The correct understanding of the on time behaviour of recycled materials, particularly those containing significant quantities of crushed concrete, is of fundamental importance in order to ensure their proper design and built on. The aim of this paper is to highlight the selfcementing properties of recycled materials, according to the evolution of the stiffness characteristics assessed at different curing times, using non destructive devices (LWDFWD). Tests carried out with these instruments allow high levels of reliability guaranteeing more detailed investigation, thus increasing the data available for Qc/Qa. The tests were performed on a trial field consisting of 4 different types of recycled materials. Results show a significant increase in stiffness, expressed in terms of Surface Modulus, as a function of the curing time. The analysis of data acquired by some pressure cells located at the base of the recycled layer allows confirming the increase of stiffness of the materials shown by the deflection test results

Low biocide emission antifouling based on a novel route of barnacle intoxication

Marine biofouling can be defined as the colonization of man-made surfaces in seawater by microscopic and macroscopic organisms. This phenomenon can result in great loss of function and effectiveness both for cruising ships and for static constructions. Of special concern are the negative effects of hard fouler such as barnacles, which cause increased drag resistance resulting in increases in fuel consumption, and disruption of the corrosion protective layer of marine vessels and constructions. Present biocide-based antifouling strategies are based on a continuous exposure of biocides at the film/water interface and consequently release into the environment if the antifouling efficacy is to be maintained. Such biocide-based solutions can therefore not be regarded as sustainable. The aim of this thesis is to describe the possibility to design biocide antifouling coatings based on a new strategy. Instead of releasing the bioactive molecule to the bulk water the biocide will be “entrapped” in the paint matrix and only after stimuli by organism interaction with the paint surface intoxication will take place. It was shown (Paper I) that using an experimental formulation, containing ivermectin, both in static panels and on boats, long lasting protection against barnacles was obtained. Moreover, using two model surfaces (Paper II), it was possible to separate and study the different contributions to the antifouling efficacy, finding that the low leaching of ivermectin had no contribution at all while surface’s modulus of the coating was the key factor. This supports the validity of the contact active antifouling hypothesis, rather than emission based. In (Paper III) we could follow the fate of barnacle growing on ivermectin containing coatings, and both field and laboratory tests could demonstrate that the intoxication of barnacles start when the juvenile organism reach ca. 0.6-0.7mm in diameter. Electronic microscopy images on the panels after the test, demonstrate that on control paint (no biocide) the juvenile barnacles (0.6-0.7mm diameter) already leaves imprint or penetration marks on the rosin based coatings. The distribution of ivermectin in the dry film seemed to be related with enhancement of barnacles contact intoxication. This was studied by fluorescence microscopy in (Paper I) and by the use ToF-SIMS in (Paper IV). This particular analytic method gives the possibility to follow organic biocides in paint film without the need of labelling or modify the biocide molecule in any extent. The entrapped antifouling strategy opens up the possibility to achieve long term antifouling (>10 years) as there is no need to use erosive binders. Moreover, this system might also find it uses in marine constructions and other fields where maintenance is difficult