Истребитель СУ-35 - в шаге от пятого поколения. Радиолокатор

14:09 19/09/07

Основу системы управления вооружением Су-35 составляет новая радиолокационная станция с фазированной антенной решеткой (ФАР). Она обладает уникальными характеристиками по дальности обнаружения и количеству сопровождаемых целей. Станция представляет собой дальнейшее развитие РЛС "Барс". ФАР обеспечивает электронное сканирование луча, как по азимуту, так и углу места. Для увеличения обзора в горизонтальной плоскости реализован дополнительный механический доворот антенны по азимуту посредством гиропривода. В режиме "воздух-воздух" радиолокатор может обнаруживать на встречных курсах на дальностях в 350-400 км и сопровождать (при сохранении непрерывности обзора пространства) до 30 целей, а также вести обстрел восьми из них. "Сверхмалоразмерные" цели с эффективной отражательной поверхностью порядка сотой доли квадратного метра обнаруживаются на дальности в 90 км. Это уникальные показатели для современных авиационных радиолокационных станций.

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Geometric Morphometrics for Biologists

Miriam Leah Zelditch, Donald L. Swiderski, H. David Sheets and William L. Fink, 2004: Geometric Morphometrics for Biologists. A Primer. Elsevier Inc. - 416 p.

ISBN: 978-0-12-778460-1

Description. This book is an introductory textbook for a course on geometric morphometrics, written for graduate students and upper division undergraduates, covering both theory of shape analysis and methods of multivariate analysis. It is designed for students with minimal math background; taking them from the process of data collection through basic and more advanced statistical analyses. Many examples are given, beginning with simple although realistic case-studies, through examples of complex analyses requiring several different kinds of methods. The book also includes URL's for free software and step-by-step instructions for using the software.

ScienceDirect - Elsevier B.V.

The Characterization of Ice Cloud Properties from Doppler Radar Measurements

Delanoë, J., Protat, A., Bouniol,  D., Heymsfield,   A., Bansemer, A. and Brown, P., 2007: The Characterization of Ice Cloud Properties from Doppler Radar Measurements. Journal of Applied Meteorology and Climatology, 46(10), 1682–1698.

Abstract. The paper describes an original method that is complementary to the radar–lidar algorithm method to characterize ice cloud properties. The method makes use of two measurements from a Doppler cloud radar (35 or 95 GHz), namely, the radar reflectivity and the Doppler velocity, to recover the effective radius of crystals, the terminal fall velocity of hydrometeors, the ice water content, and the visible extinction from which the optical depth can be estimated. This radar method relies on the concept of scaling the ice particle size distribution. An error analysis using an extensive in situ airborne microphysical database shows that the expected errors on ice water content and extinction are around 30%–40% and 60%, respectively, including both a calibration error and a bias on the terminal fall velocity of the particles, which all translate into errors in the retrieval of the density–diameter and area–diameter relationships. Comparisons with the radar–lidar method in areas sampled by the two instruments also demonstrate the accuracy of this new method for retrieval of the cloud properties, with a roughly unbiased estimate of all cloud properties with respect to the radar–lidar method. This method is being systematically applied to the cloud radar measurements collected over the three-instrumented sites of the European Cloudnet project to validate the representation of ice clouds in numerical weather prediction models and to build a cloud climatology.

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A Multipurpose Radar Simulation Package: QuickBeam

Haynes, J. M., Marchand, R. T., Luo, Z., Bodas-Salcedo, A. and Stephens, G. L., 2007: A Multipurpose Radar Simulation Package: QuickBeam. Bulletin of the American Meteorological Society, 88(11), pp. 1723–1727.

Abstract. The launch of the CloudSat cloud radar has provided some of the first near-global views of the three-dimensional structure of clouds from space. To evaluate clouds in numerical models and compare them to the observations made by CloudSat, it is useful to have a tool that converts modeled clouds to radar returns that might be viewed by a radar system on a satellite passing over the model domain. QuickBeam is a user-friendly radar simulation package that performs this function and is freely available to the meteorological community. The workings of the simulator are briefly described and several applications of the simulator to numerical models are demonstrated.

Abstract | PDF (2.55M)

The source code is written in Fortran 90 and is thus highly portable to a wide variety of platforms. The package and a more technically oriented guide to the simulator can be downloaded from http://cloudsat.atmos.colostate.edu/radarsim

Comparison of Raindrop Size Distribution Estimates From X-Band and S-Band Polarimetric Observations

Anagnostou, M. N., Anagnostou, E. N., Vivekanandan, J., Ogden, F. L., 2007: Comparison of Raindrop Size Distribution Estimates From X-Band and S-Band Polarimetric Observations. IEEE Geoscience and Remote Sensing Letters, 4(4), pp. 601-605

Abstract. This letter evaluates the consistency of rainfall drop size distribution (DSD) parameters that were estimated from attenuation-corrected X-band dual-polarization (XPOL) radar measurements with estimates from a colocated S-band dual-polarization radar (S-Pol). The DSD retrieval technique uses reflectivity and differential reflectivity, and a constrained relationship to estimate the three parameters of a “normalized” gamma distribution model. The more definitive S-Pol DSD parameter estimates are used as a reference to assess the performance of the corresponding XPOL estimates for different rain-path attenuation values. Results show that XPOL attenuation-corrected profiles can provide rainfall DSD estimations that are consistent to an S-band dual-polarization radar, even in cases of moderate to high rain-path attenuation.

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Thales Flycatcher radar