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From January 2017 to December 2021, Office National d’Etudes et de Recherches Aérospatiales (ONERA) and Centre National d’Etudes Spatiales (CNES) operated a beacon receiver able to record the 20.1995 GHz beacon signal of the Amazonas-3 satellite at the Guiana Space Centre in Kourou, French Guiana. A rain gauge was also deployed on site to collect rainfall rate measurements concurrently to beacon data. All years of the experiment, except 2019, had excellent data availability, hence giving four full years of data (2017, 2018, 2020, and 2021). First, the climatic characteristics of French Guiana are shown. Second, the propagation experiment and the data processing methodology are described. Third, the results of the statistical analysis are highlighted and commented. Comparisons are performed with the prediction methods of Recommendation ITU-R P.837-7 (rainfall rate), Recommendation ITU-R P.618-13 (rain attenuation), Recommendation ITU-R P.678-3 (variability of propagation phenomena), and Recommendation ITU-R P.1623-1 (fade dynamics). [ABSTRACT FROM AUTHOR]

Knowledge of the spatial–temporal variation of rain fields is required for the planning and optimization of wide-area high-frequency terrestrial and satellite communication networks. This article presents data and a method for characterizing multi-resolution statistical/dynamic parameters describing the spatial–temporal variation of rain fields across ocean climate in North-Western Europe. The data are derived from the NIMROD network of rain radars. The characterizing parameters include 1) statistical distribution of point 1 min rainfall rates, 2) spatial and temporal correlation functions of rainfall rate, and 3) the probability of rain/no rain. The main contributions of this article are the assessment of the impact of varying spatial and temporal integration lengths on these parameters, their dependencies on the integration volumes and area sizes, and the model for both temporal and spatial correlation parameters. [ABSTRACT FROM AUTHOR]

This contribution describes a realistic rain model that considers a cluster of axis-symmetric but flattened raindrops with a specified shape–size relation, a raindrop size distribution, and a distribution of orientation angle of the symmetry axis. The backscattering cross section and specific attenuation due to the rain medium are determined by the extended boundary condition method. The model is applied to data from two X-band radars to estimate reflectivity and rainfall rate, considering attenuation effects during the two-way propagation between the radar and each sampled rain volume. The results are then compared with corresponding ones from well-established attenuation-correction methods. One of these methods, which relies on unattenuated reflectivities measured by an S-band radar, has been carefully validated by a previous study. The reasonable agreement between the two methods indicates that the proposed model may be a suitable option to estimate reflectivity and rainfall rate fields based on X-band radar data, particularly when no such references are available. [ABSTRACT FROM AUTHOR]

The Ka-band propagation experiments conducted by ONERA in Toulouse (43.57°E, 1.47°N) in the southwest of France started in 2009 and is still on-going. The equipment comprises a beacon Earth station, a profiling radiometer, and a rain gauge. The ground station measures the received beacon signal using a 10-Hz sampling rate. The profiling radiometer measures the sky brightness temperatures at five Ka-band and seven V-band channels, surface temperature, surface humidity, and surface pressure. From July 2009 to March 2011, the beacon receiver recorded the 19.7-GHz (horizontal polarization) HotBird 6 beacon signal along a slant path of 38.6° of elevation angle. Since April 2011, the beacon receiver has been recording the 20.2-GHz (vertical polarization) Astra 3B beacon signal along a slant path of 35.1° of elevation angle. This paper aims at providing a complete description of the ONERA Data Processing Tool (in particular the methodology followed to retrieve total attenuation) used to compute 4 years (from July 2009 to June 2013) of copolar attenuation statistics. The experimental setup and the characteristics of the Earth-space links are briefly described. The complementary cumulative distribution function (CCDF) of total attenuation for the whole period is presented and compared with ITU-R recommendations. The measured CCDF of the rainfall rate is computed and compared with ITU-R Rec. P.837 and will also be used as input for the rain attenuation model given in ITU-R Rec. P.618. The measured CCDFs of total attenuation duration and total attenuation slope are also presented. [ABSTRACT FROM PUBLISHER]