Microwave link derived rain rates show good correlation with ground observations, but can often suffer from large biases when applying only a standard ITU-R equation. The ITU-R equation describes the relation between path attenuation and rain rate, but other effects like wetting of the antenna can occur. Since 2015 SMHI has a semi-operational processing method that tries to correct these...
Since September 2017 we gather data from around 4000 CMLs distributed over all landscapes of Germany at a temporal resolution of one minute.
We present a fast, parallelized workflow with a processing scheme composed from methods from literature, that were adjusted to our data set. This includes the comparison of different methods to classify wet and dry periods and to compensate for wet...
Commercial microwave links are installed and maintained for the purpose of telecommunication. Hydrometeors between transmitting and receiving antennas cause the microwave signal to be attenuated. From signal attenuation, the path-averaged rainfall intensity can be calculated. A 7-month dataset of instantaneously logged signal powers from almost 2000 unique links in The Netherlands is analyzed....
Many different algorithms and approaches for the retrieval of rain using CMLs measurements have been presented in the past. In general, these algorithms can be divided into two groups, based on the different type of the available measurements: A) algorithms that make use of the standard network management system 15-minute min/max measurements; B) algorithms that make use of instantaneous...
CML data might exhibit high signal fluctuations, even during dry periods. At the same time the number of newly available CMLs is rising fast. It is necessary to develop a technique to recognise the pattern of rainfall in CML signal levels, that is (1) generalizing to previously unknown sensors, (2) stable in time and (3) showing better performance than established methods. We therefore...
This talk will give an introduction to fundamental antenna parameters and characteristics like gain, directivity, efficiency, and reflection coefficient. It will debate the impact of wetness on the antenna cover on these parameters and on the link attenuation as a whole.
The impact of water on electromagnetic wave propagation is explained based on the canonical example of a thin water layer...
This contribution presents the ability of individual CMLs to provide relevant QPEs for rainfall-runoff simulations, specifically, the influence of CML characteristics and position on the predicted runoff. The analysis is based on a 3-year-long experimental data set from a small (1.3 km2) urban catchment located in Prague, Czech Republic. QPEs from real world CMLs are used as inputs for an...
The current study proposes a new method to process Commercial Microwave Links (CML) data for rainfall estimation.
Since the concept was introduced in the mid-2000, several papers have discussed and illustrated how rain-induced fluctuations could be used to quantify rainfall.
Most previous work on the subject is based on applying a power-law relationship between the attenuation over the link...
The difficulty when using path-averaged rain rates derived from commercial microwave links (CMLs) is, that they give non-linear constrains for the precipitation field. To address this challenge, we apply Random Mixing to stochastically simulate precipitation fields. We generate precipitation fields as linear combinations of unconditional spatial random fields, where the spatial dependence...
In this contribution, we present the results of the simulations carried out during the testing phase
of the tomographic reconstruction algorithm, developed in the framework of the MOPRAM project. To this purpose, we exploited a large data set of radar rain maps (assumed as ground truth) and assumed a realistic distribution of microwave links over the area of interest. We considered both...
Creating an interpolated gridded map based on local measurements is commonly done in a straightforward way using IDW or kriging. The chosen output resolution is usually the same as the resolution of a field to be compared with (i.e. interpolated rain gauges and radar) or it is defined by the required parameters of a model. But how to choose an optimal resolution based on the input data? We...
Abstract
In the last decade, various algorithms have been developed to provide accurate rainfall maps from measurements of rain-induced attenuation on commercial wireless links (CWLs), such as [1].
These solutions provide precise results but they also require dense terrestrial microwave networks, which have non negligible installation and operating costs.
A cheaper alternative for...
TBA
New generation of E-band commercial microwave links (CMLs) operating at frequency band 70 - 86 GHz is gradually completing cellular backhaul networks and especially in cities often replacing older devices. CML rainfall retrieval methods developed during last decade have been designed and tested for frequency bands 20-40 GHz, where path attenuation caused by raindrops is almost linearly related...
