High-Altitude Imaging Wind and Rain Airborne Radar (HIWRAP)

Li, Lihua; Heymsfield, Gerald M.; Carswell, J.; Schaubert, D.H.; Creticos, J.P.; Vega, Manuel A.

doi:10.1109/igarss.2008.4779356

Cited by 16 publications

(11 citation statements)

References 2 publications

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“…The frequency dependence of backscattering efficiency (when size parameter becomes similar to the wavelength) and extinction efficiency have motivated the development of radar systems operating at two or more frequencies (e.g., Sadowy et al, 2003, Li et al, 2008 or separate radars with matched beams (e.g., Chandrasekhar et al, 2010 so that these differences can be used to further constrain the range-resolved parameters of the PSD. For any pair of frequencies υ1 and υ2, where υ1 < υ2, the dual-frequency ratio (DFR) is defined as:…”

Section: [[H1]] Multi-frequency Methodsmentioning

confidence: 99%

Remote Sensing of Precipitation from Airborne and Spaceborne Radar

Munchak

2018

Remote Sensing of Aerosols, Clouds, and Precipitation

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Weather radar measurements from airborne or satellite platforms can be an effective remote sensing tool for examining the three-dimensional structures of clouds and precipitation. This chapter describes some fundamental properties of radar measurements and their dependence on the particle size distribution (PSD) and radar frequency. The inverse problem of solving for the vertical profile of PSD from a profile of measured reflectivity is stated as an optimal estimation problem for single-and multi-frequency measurements. Phenomena that can change the measured reflectivity Zm from its intrinsic value Ze, namely attenuation, non-uniform beam filling, and multiple scattering, are described and mitigation of these effects in the context of the optimal estimation framework is discussed. Finally, some techniques involving the use of passive microwave measurements to further constrain the retrieval of the PSD are presented. [[H1]] IntroductionThe ability of weather radar to measure the location and intensity of precipitation was rapidly realized in the late 1940s following World War II. However, ground-based radars are limited in their ability to directly detect precipitation close to the ground far from the radar site due to ground clutter, refraction of the radar beam, and the curvature of the earth. Beam blockage by terrain also poses problems for radar coverage in mountainous areas. Coverage over oceans and other remote areas, where maintaining a ground radar would be difficult and costly, is also impractical, yet the precipitation that falls in these regions has important impacts on the global https://ntrs.nasa.gov/search.jsp?R=20180000191 2018-05-12T19:37:19+00:00Z atmospheric circulations via latent heating (e.g., Hoskins and Karoly, 1981, Hartmann et al., 1984, Matthews et al., 2004 and can have a profound influence on weather patterns thousands of kilometers away. Likewise, knowledge of precipitation over land, particularly in the form of snow, is a crucial component of the mass balance equation for glaciers and ice sheets, which must be properly characterized for realistic climate simulations (Shepherd et al., 2012).Airborne radar systems can provide high sensitivity and finely resolved vertical profiles to characterize precipitation microphysics for the benefit of model parameterizations and process understanding (e.g., Reinhardt et al, 2010, Heymsfield et al., 2013, Rauber et al., 2016.However, in order to achieve true global coverage, it had been proposed from nearly the beginning of the space age to put a weather radar in space (Kreigler and Kawitz, 1960), and efforts to do so began in earnest in the late 1970s and 1980s with the planning of the Tropical Rainfall Measuring Mission satellite (TRMM; Simpson et al., 1987, Okamoto et al., 1988 increased accuracy, sensitivity, and extension to higher latitudes. Both the TRMM PR and GPM DPR were intended not only to estimate precipitation directly from the radar data but also to construct a database of precipitation profiles to unify precipitation retri...

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Section: [[H1]] Multi-frequency Methodsmentioning

confidence: 99%

Remote Sensing of Precipitation from Airborne and Spaceborne Radar

Munchak

2018

Remote Sensing of Aerosols, Clouds, and Precipitation

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“…Airborne remote sensing using active radars has become an effective tool in geoscience fields for conducting Earth observations [1][2][3]. Compared to satellite observations, airborne platforms are capable of spatially finer-resolution measurements over large areas.…”

Section: Introductionmentioning

confidence: 99%

Sensor-Driven Preliminary Wing Ground Plane Sizing Approach and Applications

Patil

Arnold

2018

International Journal of Aerospace Engineering

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Structurally integrated antenna arrays provide synergies allowing the integration of large apertures onto airborne platforms. However, the surrounding airframe can greatly impact the performance of the antenna array. This paper presents a sensor-driven preliminary wing ground plane sizing approach to provide insight into the implications of design decisions on payload performance. The improvement of a wing-integrated antenna array that utilizes the wing as a ground plane motivated this study. Relationships for wing span, wing chord, and thickness are derived from extensive parametric electromagnetic simulations based on optimum antenna performance. It is expected that these equations would be used after an initial wing-loading design point has been selected to provide the designer guidance into how various wing parameters might affect the integrated antenna performance.

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“…A new airborne scanning Doppler radar, the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP), has been developed recently at NASA Goddard Space Flight Center (Li et al 2008). It is a downward-pointing, conically scanning Doppler radar system with dual frequency (Ku and Ka bands) and dual beams (308 and 408 incidence angles), with the capability to provide information about three-dimensional reflectivity and wind structures in precipitating systems and ocean surface winds in rain-free regions.…”

Section: Introductionmentioning

confidence: 99%

Velocity–Azimuth Display Analysis of Doppler Velocity for HIWRAP

Tian

Heymsfield

Didlake

et al. 2015

Journal of Applied Meteorology and Climatology

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The velocity-azimuth display (VAD) analysis technique established for ground-based scanning radar is applied to the NASA High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP). The VAD technique provides a mean vertical profile of the horizontal winds for each complete conical scan of the HIWRAP radar. One advantage of this technique is that it has shown great value for data assimilation and for operational forecasts. Another advantage is that it is computationally inexpensive, which makes it suitable for real-time retrievals. The VAD analysis has been applied to the HIWRAP data collected during NASA's Genesis and Rapid Intensification Processes (GRIP) mission. The traditional dual-Doppler analysis for deriving wind fields in the nadir plane is also presented and is compared with the VAD analysis. The results show that the along-track winds from the VAD technique and dual-Doppler analysis agree in general. The VAD horizontal winds capture the mean vortex structure of two tropical cyclones, and they are in general agreement with winds from nearby dropsondes. Several assumptions are made for the VAD technique. These assumptions include a stationary platform for each HIWRAP scan and constant vertical velocity of the hydrometeors along each complete scan. As a result, the VAD technique can produce appreciable errors in regions of deep convection such as the eyewall, whereas in stratiform regions the retrieval errors are minimal. Despite these errors, the VAD technique can still adequately capture the larger-scale structure of the hurricane vortex given a sufficient number of flight passes over the storm.

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High-Altitude Imaging Wind and Rain Airborne Radar (HIWRAP)

Cited by 16 publications

References 2 publications

Remote Sensing of Precipitation from Airborne and Spaceborne Radar

Remote Sensing of Precipitation from Airborne and Spaceborne Radar

Sensor-Driven Preliminary Wing Ground Plane Sizing Approach and Applications

Velocity–Azimuth Display Analysis of Doppler Velocity for HIWRAP

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