Vertical air motion retrievals in deep convective clouds using the ARM scanning radar network in Oklahoma during MC3E
The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Southern Great Plains (SGP) site includes a heterogeneous distributed scanning Doppler radar network suitable for collecting coordinated Doppler velocity measurements in deep convective clouds. The surroundi...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-08-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/10/2785/2017/amt-10-2785-2017.pdf |
| Summary: | The US Department of Energy (DOE) Atmospheric Radiation
Measurement (ARM) program's Southern Great Plains (SGP) site includes a
heterogeneous distributed scanning Doppler radar network suitable for
collecting coordinated Doppler velocity measurements in deep convective
clouds. The surrounding National Weather Service (NWS) Next Generation
Weather Surveillance Radar 1988 Doppler (NEXRAD WSR-88D) further supplements
this network. Radar velocity measurements are assimilated in a
three-dimensional variational (3DVAR) algorithm that retrieves horizontal
and vertical air motions over a large analysis domain (100 km × 100 km) at storm-scale resolutions (250 m). For the first time, direct
evaluation of retrieved vertical air velocities with those from collocated
915 MHz radar wind profilers is performed. Mean absolute and
root-mean-square differences between the two sources are of the order of 1 and 2 m s<sup>−1</sup>, respectively, and time–height correlations are of
the order of 0.5. An empirical sensitivity analysis is done to determine a
range of 3DVAR constraint weights that adequately satisfy the velocity
observations and anelastic mass continuity. It is shown that the vertical
velocity spread over this range is of the order of 1 m s<sup>−1</sup>. The 3DVAR
retrievals are also compared to those obtained from an iterative upwards
integration technique. The results suggest that the 3DVAR technique provides
a robust, stable solution for cases in which integration techniques have
difficulty satisfying velocity observations and mass continuity
simultaneously. |
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| ISSN: | 1867-1381 1867-8548 |