Preliminary Study on the Feasibility of Performing Quantitative Precipitation Estimation Using X-band Radar

IRCTR has built an experimental X-band Doppler po-larimetric weather radar system aimed at obtaining high temporal and spatial resolution measurements of precipitation, with particular interest in light rain and drizzle. In this paper a first analysis of the feasibility of obtaining accurate quantitative precipitation estimation from the radar data performed using a high density network of rain gauges is presented

Shaner leaves legacy of leadership, strong teaching

Radar range: standard. Max rain level: moderate rain

Dynamic Validation Logic Generation using Business Rules Management Systems

Input validation in web applications represents an important part of their functionality. With proper validation we ensure that provided input data is in accordance with technical constraints, defined by the developer and with business-related constraints. In web development frameworks, validation logic is coupled with program code. If one validation rule is changed, application needs to be recompiled and redeployed. In this thesis we developed a system for input validation based on business rules management system. Validation rules are stored in central repository, separated from implementation of web applications. Thus, we have achieved a simple and transparent way of declaring validation logic in the form of declarative business rules as well as simplifed applications maintenance in case of changes in validation logic

Ground-based remote sensing of precipitation using a multi-polarized FM-CW Doppler radar

Electrical Engineering, Mathematics and Computer Scienc

High-resolution polarimetric X-band weather radar observations at the Cabauw Experimental Site for Atmospheric Research

In 2007, the horizontally scanning polarimetric X-band radar IDRA (IRCTR Drizzle Radar) was installed on top of the 213 m high mast at the Dutch meteorological observatory Cabauw Experimental Site for Atmospheric Research (CESAR) at Netherlands. This radar complements a large variety of measurement instruments at CESAR by providing information on the horizontally spatial distribution and the temporal evolution of precipitation around the site. IDRA is a frequency-modulated continuous-wave radar developed at TU Delft's International Research Centre for Telecommunications and Radar (IRCTR). IDRA is designed to provide a high spatial resolution (down to 3 m in range) at a temporal resolution of 1 min. Its central frequency of 9.475 GHz, sensitive receivers with a large dynamic range, and the possibility to adjust the power of the transmitted signal permit IDRA to measure the whole spectrum of meteorological echoes from low-level clouds and drizzle to heavy convective rain. Similarly to most data collected at CESAR, also the data collected by IDRA are freely available for scientific purposes. IDRA data are stored at the Dutch 3TU.Datacentrum in order to make it easily accessible for everyone. In this article, we outline the IDRA dataset, including details on the data acquisition, processing, and possible applications.Geoscience & Remote SensingCivil Engineering and Geoscience

A framework for cloud - Aerosol interaction study

Aerosols can indirectly influence climate either by cloud albedo or lifetime effect. In order to have better understanding of these processes it is crucial to measure detailed vertical profiles of the radiative transfer and the microphysical evolution of clouds. Best results can be achieved by using advanced sensor synergy techniques. Essential remote sensing instruments used in this study include cloud radars and different types of lidar to obtain vertical structure of the atmosphere, as well as microwave radiometers and radiation sensors for improving the accuracy of the retrieved profiles. Several advanced combined retrieval algorithms will be used to quantify the physical characterization of water clouds and aerosols. Further work will be required on the understanding of the relation between cloud and aerosol.Geoscience and Remote ControlCivil Engineering and Geoscience

Novel method of drizzle formation observation at large horizontal scales using multi-wavelength satellite imagery simulation

The observations of on-board satellite imaging radiometers are representative of a far-reaching two-dimensional cloud top properties, however with a cutback in the capacity of profiling the cloud vertically. A combination of simulated radiances calculated at the top of the cloud in the near-infrared (IR) and thermal infrared part of the spectra, is used as a proxy to estimate in-cloud droplet growth stage and ongoing precipitation intensity at the water cloud base. We present a drizzle observational technique that is built on simulated satellite imaging radiometry via the EarthCARE SIMulator (ECSIM). A period of 40 hours of the modeled cloud field evolution (using Dutch Atmospheric Large Eddy Simulator - DALES) for the case study during the Atlantic Stratocumulus Transition Experiment campaign (ASTEX) is used to create a series of cloud scenes of a transitioning Sc into a Sc topped Cumulus (Cu) fields. Drizzle appears throughout the cloud evolution, evaporating on its way to the surface, depleting the cloud droplets at the cloud base. Longwave radiation model from ECSIM is applied to the ingested three-dimensional cloud scenes of a Stratocumulus evolution. The cloud top brightness temperatures are calculated using a three-dimensional, Monte Carlo, long-wave Radiative Transfer Model (RTM). The simulated Brightness Temperatures Difference (BTD) between the channels 3.9 and 11mm is then used to highlight the cloud top droplet size spatial variability, during the production of drizzle near the cloud base. The observed correlation of the BTD with the droplet size variability is used to interpret the conditions at which the precipitation at the cloud base is triggered or went through a change in the intensity. Tracking the process of evolution of the cloud droplet into a precipitating drop is likely due to the sensitivity of the 3.9mm channel to the particle size and cloud phase, near the cloud top. A comparison of the observed BTD with the vertically averaged cloud droplet size from the imported cloud scene is done. It is used to examine if a single pixel value of BTD from the cloud top (as retrieved via RTM) can be representative of the inhomogeneous microphysical vertical structure of a Sc deck and the potential precipitation intensity at the cloud base. A range in BTD for the two infra-red channels, between 0 and 2K is correlated to the presence of effective radius of the cloud droplets larger than 15mm, treated as drizzle drops in this paper.Geoscience & Remote SensingCivil Engineering and Geoscience

Ground-based remote sensing scheme for monitoring aerosol–cloud interactions (discussion)

A method for continuous observation of aerosol–cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of cloud microphysical changes due to the changing aerosol concentration. We use high resolution measurements from lidar, radar and radiometer which allow to collect and compare data continuously. This method is based on a standardised data format from Cloudnet and can be implemented at any observatory where the Cloudnet data set is available. Two example study cases were chosen from the Atmospheric Radiation Measurement (ARM) Program deployment at Graciosa Island, Azores, Portugal in 2009 to present the method. We show the Pearson Product–Moment Correlation Coefficient, r, and the Coefficient of Determination, r2 for data divided into bins of LWP, each of 10 g m?2. We explain why the commonly used way of quantity aerosol cloud interactions by use of an ACI index (ACIr,? = dln re,?/dln?) is not the best way of quantifying aerosol–cloud interactions.Geoscience & Remote SensingCivil Engineering and Geoscience