Historically the atmospheric and meteorological communities are separate worlds with their own data formats and tools
for data handling making sharing of data difficult and cumbersome. On the other hand, these information sources are
becoming increasingly of interest outside these communities because of the continuously improving spatial and temporal
resolution of e.g. model and satellite data and the interest in historical datasets. New user communities that use
geographically based datasets in a cross-domain manner are emerging. This development is supported by the progress
made in Geographical Information System (GIS) software. The current GIS software is not yet ready for the wealth of
atmospheric data, although the faint outlines of new generation software are already visible: support of HDF, NetCDF
and an increasing understanding of temporal issues are only a few of the hints.
In a previous work, an operative procedure to estimate precipitable and liquid water in non-raining conditions over sea was developed and assessed. The procedure is based on a fast non-linear physical inversion scheme and a forward model; it is valid for most of satellite microwave radiometers and it also estimates water effective profiles. This paper presents two improvements of the procedure: first, a refinement to provide modularity of the software components and portability across different computation system architectures; second, the adoption of the CERN MINUIT minimisation package, which addresses the problem of global minimisation but is computationally more demanding. Together with the increased computational performance that allowed to impose stricter requirements on the quality of fit, these refinements improved fitting precision and reliability, and allowed to relax the requirements on the initial guesses for the model parameters. The re-analysis of the same data-set considered in the previous papers showed an improvement of the consistency of the estimates from SSM/I and TMI radiometers and of the agreement with the statistical references. The described work confirmed the stability of the overall approach of the operative Procedure and prepared for new satellite generations (e.g. AMSR-E).
The present work empirically deals with the challenging problem of the integration of data obtained from passive and active microwave sources, in order to develop procedures to suitably calibrate and validate satellite-based passive microwave rainfall algorithms by means of multi parameter radar information over midlatitude areas. Furthermore, this research tires to analyze the well-known beam-filling problem and the different microwave channel penetration top9ic. SSM/I passive microwave radiometer precipitation related parameters were analyzed against multi parameter radar Zh and Zdr 3D maps, obtained from the POLAR-55C multi parameter radar set near Florence, Italy. SSM/I-derived parameters, related to rainfall over land were analyzed by means of information derived form radar volume data. We faced several statistical analyses of the obtained data sets. Results report the effectiveness of Montagnana radar and SSM/I data fusion. In particular, it is assessed the utility of utilizing both active and passive microwave hydrometeor-related information in order to improve the inferences about monitored phenomena. Results are valuable in order to better calibrate and validate passive microwave algorithms for rainfall rate estimation and for cloud detection over land. Correlation values may be improved by filtering radar data according to several parameters thresholds, in order to tackle beam-filling problem and statistical issues.
A numerical monochromatic polarized plane-parallel radiative transfer code over sea has been developed for a non-scattering atmosphere in local thermodynamical equilibrium. In present work a non-linear inversion technique has been applied, based on the Levenberg-Marquardt Method, to a TMI late summer scene over the South of Mediterranean Sea. Temperature, water vapor and cloud liquid water atmospheric profiles have been retrieved over a wind-roughened sea surface. Eventually, integrated water vapor and cloud liquid water content have been estimated. A quasi-contemporary SSM/I acquisition over the same region has been utilized to derive integrated water vapor and cloud liquid water burden, using a statistical well- known algorithm. The TMI and SSM/I derived estimates are then compared for the selected scene.
Knowledge of water cycle in the atmosphere: that is the amount of water in its three phases is very useful for several applications, such as: weather forecasting, latent heat flux estimation, sea-atmosphere interaction. The present work showed a comparison of total precipitable water and cloud liquid water content retrievals from the well-known SSM/I and the new TMI radiometers, utilizing a physical-based inversion scheme -- developed at the PIN of the University of Florence. The estimations obtained through the physical-based inversion scheme are compared against those worked out thorough well- accepted empirical scheme based on SSM/I data. Hence, a validation of the physical-based inversion scheme, was achieved. For this purpose, a specific data-set was collected and analyzed, obtaining near-coincident crossing of the two radiometers over the Mediterranean sea. This is a contribution to understand the applicability of algorithms developed for the SSM/I towards the TMI, and to assess the improvement due to this new instrument (i.e. TMI). The statistical results show the goodness at utilizing the physical inversion model to estimate useful parameters such as atmosphere total precipitable water distribution over the Mediterranean area, from both the SSM/I and the TMI radiometers, and demonstrate a good retrieval accuracy. That is important especially for data-assimilation applications.
Knowledge of water cycle in the atmosphere is very useful for several climatological and meteorological applications. This work presents a forward model of atmospheric emission in clear sky conditions, over Mediterranean sea. Solving a polarized radiative transfer scheme, brightness temperatures at the top of atmosphere were calculated. By fitting such temperatures against those measured by he SSM/I microwave radiometer effective vertical profiles of atmospheric water vapor were retrieved. Eventually, total precipitable water values were estimated. These values were compared with those obtained through statistical well-known algorithms from SSM/I brightness temperatures. The reported procedure was applied on a dataset, made up of Mediterranean scenes acquired during summer. The present work showed the feasibility of obtaining total precipitable water estimates as accurate as statistical ones; moreover, this approach provides information about the effective vertical atmospheric temperature, pressure and water vapor profiles, that allows this procedure to be more flexible and reliable, both form a spatial and a temporal point of view. Therefore, we characterized the presented research, calibrating our procedure for the Mediterranean area: a relative poor region, as far as field observation are concerned.
This paper reports the experimentation of a joint use of ground-based radar and satellite radiometer to calibrate and validate passive microwave data for rainfall monitoring. In particular, the utilization of radar vertical profile maps in order to figure out the passive microwave signatures is outlined. The experimentation has been conducted utilizing active microwave data acquired from the Chilbolton radar and passive microwave data acquired from the DMSP SSM/I instruments. The two microwave data type have been processed in order to be overlayable in time and space, and several parameters have been estimated from the SSM/I data. Radar vertical profile maps have been classified to outline the cloud structure and the obtained information have been utilized to make statistical analysis of passive microwave parameters related to rainfall over land. In particular, an attempt to divide the cloud structure into three meaningful layers has been worked out; this is important as the different channels of SSM/I can penetrate in a diverse way cloud structure. The result are in accordance to theory and outline the importance of utilizing radar vertical profiles in order to figure out the passive microwave measurements.
The present work empirically deals with the challenging problem of the integration of data obtained from passive and active microwave sources, in order to develop procedures to suitably calibrate and validate satellite-based passive microwave rainfall algorithms by means of multiparameter radar information over midlatitude areas. SSM/I passive microwave radiometer precipitation related parameters have been analysed against multiparameter radar Zh and Zdr three dimensional maps, obtained from the POLAR-55C multiparameter radar set near Florence, Italy. The main objectives of this work are: to try to better analyse the satellite beam-filling problem and its different channel penetration topic; to design and validate an operational procedure in order to integrate SSMfl and the POLAR -55C data. Starting from radar-derived volumetric information and passive microwave multi-frequency data, we have faced several statistical analyses of the obtained data sets. Results report the effectiveness of Montagnana radar and SSM/I data fusion. In particular, it was outlined the· diverse influence that different vertical profile layers have on radiometer channels. Radar measurements versus SSM/I parameters correlation values may be improved by filtering radar data according to several parameters thresholds, in order to tackle beam-filling problem and statistical issues. Eventually, utilised hydrometeor classification schemes seems not to work properly for a whole stack of CAPPis. Keywords: Microwave, Radar, Data Integration, Vertical structure, Statistical Analysis
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