The Simple Rectification to Cartesian Space of Folded Radial Velocities from Doppler Radar Sampling

Miller, L. Jay; Mohr, Carl G.; Weinheimer, A. J.

doi:10.1175/1520-0426(1986)003<0162:tsrtcs>2.0.co;2

Cited by 46 publications

(38 citation statements)

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“…For this study, an automated algorithm was utilized to unfold radial velocity measurements outside the radar Nyquist velocity range following a procedure described in Miller et al (1986). Specifically, radial velocities were "locally" unfolded during the interpolation to caretesian space using the NCAR REORDER software package .…”

Section: Methodsmentioning

confidence: 99%

An Ensemble Study of Wet Season Convection in Southwest Amazonia: Kinematics and Implications for Diabatic Heating

et al. 2004

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Dual-Doppler radar data from the Tropical Rainfall Measuring Mission Large Scale Biosphere–Atmosphere Experiment in Amazonia (TRMM-LBA) field campaign are used to determine characteristic kinematic and reflectivity vertical structures associated with precipitation features observed during the wet season in the southwest region of Amazonia. Case studies of precipitating systems during TRMM-LBA as well as overarching satellite studies have shown large differences in convective intensity associated with changes that develop in low-level easterly flow [east regime (ER)] and westerly flow [west regime (WR)]. This study attempts to examine the vertical kinematic and heating structure of convection across the spectrum of precipitation features that occurred in each regime. Results show that convection in the ER is characterized by more intense updrafts and larger radar reflectivities above the melting level, in agreement with results from lightning detection networks. These regime differences are consistent with contrasts in composite thermal buoyancy between the regimes: above the boundary layer, the environment in the ER is characterized by a greater virtual temperature excess for near-surface rising parcels. Both regimes showed a peak in intensity during the late afternoon hours, as evidenced by radar reflectivity and kinematic characteristics, consistent with previous studies of rainfall and lightning in the Rondônia (TRMM-LBA) region. After sunset, however, convective intensity in the WR decreases much more abruptly compared to the ER. In the stratiform–weak convective region, the ER showed both reflectivity and kinematic characteristics of classic stratiform structure after sunset through the early morning hours, consistent with the life cycle of mesoscale conjective systems (MCSs). Apparent heating (Q1) profiles were constructed for each regime assuming the vertical advection of dry static energy was the dominant forcing term. The resulting profiles show a peak centered near 8 km in the convective regions of both regimes, although the ER has a broader maximum compared to the WR. The breadth of the ER diabatic heating peak is consistent with the more dominant role of ice processes in ER convection.

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Section: Methodsmentioning

confidence: 99%

An Ensemble Study of Wet Season Convection in Southwest Amazonia: Kinematics and Implications for Diabatic Heating

et al. 2004

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“…Commonly used schemes for gridding such observations to 3-D Cartesian space are the distance-dependent weighted averaging schemes based on the Cressman (1959) and Barnes (1964) weighting functions (Nelson, 1980;Askelson, 1996). Other applied schemes are those based on the nearestneighbor method (Jorgensen et al, 1983) and on bilinear interpolation (Mohr and Vaughan, 1979;Miller et al, 1986;Fulton, 1998). Trapp and Doswell III (2000) analyzed the various theoretical aspects of these schemes and recommended that both the choice of interpolation scheme and the choice of weighting function parameters should be problem specific.…”

Section: Radar Interpolation Schemesmentioning

confidence: 99%

Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

Lamer

Tatarevic

et al. 2014

Atmos. Meas. Tech.

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Abstract. The scanning Atmospheric Radiation Measurement (ARM) cloud radars (SACRs) provide continuous atmospheric observations aspiring to capture the 3-D cloudscale structure. Sampling clouds in 3-D is challenging due to their temporal-spatial scales, the need to sample the sky at high elevations and cloud radar limitations. Thus, a suggested scan strategy is to repetitively slice the atmosphere from horizon to horizon as clouds advect over the radar (Cross-Wind Range-Height Indicator -CW-RHI). Here, the processing and gridding of the SACR CW-RHI scans are presented. First, the SACR sample observations from the ARM Southern Great Plains and Cape Cod sites are post-processed (detection mask, gaseous attenuation correction, insect filtering and velocity de-aliasing). The resulting radial Doppler moment fields are then mapped to Cartesian coordinates with time as one of the dimensions. Next the Cartesian-gridded Doppler velocity fields are decomposed into the horizontal wind velocity contribution and the vertical Doppler velocity component. For validation purposes, all gridded and retrieved fields are compared to collocated zenith-pointing ARM cloud radar measurements. We consider that the SACR sensitivity loss with range, the cloud type observed and the research purpose should be considered in determining the gridded domain size. Our results also demonstrate that the gridded SACR observations resolve the main features of low and high stratiform clouds. It is established that the CW-RHI observations complemented with processing techniques could lead to robust 3-D cloud dynamical representations up to 25-30 degrees off zenith. The proposed gridded products are expected to advance our understanding of 3-D cloud morphology, dynamics and anisotropy and lead to more realistic 3-D radiative transfer calculations.

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“…In advance of being assimilated, radar data are pre-processed using the methods given by Park and Lee (2009). The preprocessing includes quality control, interpolation/thinning to Cartesian grids by the Sorted Position Radar INTerpolation (SPRINT; Mohr and Vaughan, 1979;Miller et al, 1986) and Custom Editing and Display of Reduced Information in Cartesian coordinate (CEDRIC; Mohr et al, 1986) packages and hole-filling/smoothing by the CEDRIC package. The details of the quality control are as follow.…”

Section: Experimental Designmentioning

confidence: 99%

Radar radial wind data assimilation using the time-incremental 4D-Var method implemented to the WRFDA system

Choi¹,

Lim

Lee

2013

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C TIn this study, we selected a heavy rainfall case over the Korean Peninsula, which was characterised by two localised rainfall maxima. Neither of the two maxima is accurately simulated when no radar data are assimilated or when radar data are assimilated using the three-dimensional variational (3D-Var) method of the Weather Research and Forecasting Data Assimilation (WRFDA) system. Using the four-dimensional variational (4D-Var) method included in the WRFDA system improves the rainfall forecast partially. To obtain further improvements in the rainfall forecast, outer loops and the time-incremental 4D-Var method are used. In the time-incremental 4D-Var method, the length of the assimilation window is increased gradually, and the starting point of the current minimisation task comes from the minimiser of the previous minimisation task. The analysis of the experiment using outer loops or the time-incremental 4D-Var method is closer to the observations than that of the experiment using the 4D-Var method. This is because the first guess is improved progressively by using outer loops or the time-incremental 4D-Var method. The gap between nonlinear and linear growth is reduced via outer loops or the time-incremental 4D-Var method compared to the 4D-Var method, because the nonlinearity is accounted for by consistently updating the nonlinear model trajectory. However, the rainfall forecast is improved only in the experiment using the time-incremental 4D-Var method. Analysis increments of the horizontal wind and convective available potential energy (CAPE) result in proper modifications to the analysis, and finally, an improved subsequent forecast. The quasi-static adjustment in the time-incremental 4D-Var method may contribute to finding the global minimum under the high degree of nonlinearity present in the original minimisation problem.

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The Simple Rectification to Cartesian Space of Folded Radial Velocities from Doppler Radar Sampling

Cited by 46 publications

References 0 publications

An Ensemble Study of Wet Season Convection in Southwest Amazonia: Kinematics and Implications for Diabatic Heating

An Ensemble Study of Wet Season Convection in Southwest Amazonia: Kinematics and Implications for Diabatic Heating

Evaluation of gridded scanning ARM cloud radar reflectivity observations and vertical doppler velocity retrievals

Radar radial wind data assimilation using the time-incremental 4D-Var method implemented to the WRFDA system

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