Preliminary results of 3D hurricane boundary layer wind estimation with multilook Doppler radar measurements of the precipitation

AbstractThe coplane analysis technique for mapping the three-dimensional wind field of precipitating systems is applied to the NASA High-Altitude Wind and Rain Airborne Profiler (HIWRAP). HIWRAP is a dual-frequency Doppler radar system with two downward-pointing and conically scanning beams. The coplane technique interpolates radar measurements onto a natural coordinate frame, directly solves for two wind components, and integrates the mass continuity equation to retrieve the unobserved third wind component. This technique is tested using a model simulation of a hurricane and compared with a global optimization retrieval. The coplane method produced lower errors for the cross-track and vertical wind components, while the global optimization method produced lower errors for the along-track wind component. Cross-track and vertical wind errors were dependent upon the accuracy of the estimated boundary condition winds near the surface and at nadir, which were derived by making certain assumptions about the vertical velocity field. The coplane technique was then applied successfully to HIWRAP observations of Hurricane Ingrid (2013). Unlike the global optimization method, the coplane analysis allows for a transparent connection between the radar observations and specific analysis results. With this ability, small-scale features can be analyzed more adequately and erroneous radar measurements can be identified more easily.

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NSSL Dual-Doppler Radar Measurements in Tornadic Storms: a Preview

Bulletin of the American Meteorological Society ◽

10.1175/1520-0477(1975)056<0524:nddrmi>2.0.co;2 ◽

1975 ◽

Vol 56 (5) ◽

pp. 524-526 ◽

Cited By ~ 11

Author(s):

Rodger A. Brown ◽

Donald W. Burgess ◽

John K. Carter ◽

Leslie R. Lemon ◽

Dale Sirmans

Keyword(s):

Doppler Radar ◽

Radar Measurements ◽

Tornadic Storms ◽

Dual Doppler Radar

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Doppler Profiler and Radar Observations of Boundary Layer Variability during the Landfall of Tropical Storm Gabrielle

Journal of the Atmospheric Sciences ◽

10.1175/jas3608.1 ◽

2006 ◽

Vol 63 (1) ◽

pp. 234-251 ◽

Cited By ~ 39

Author(s):

Kevin R. Knupp ◽

Justin Walters ◽

Michael Biggerstaff

Keyword(s):

Boundary Layer ◽

Doppler Radar ◽

Layer Structure ◽

Flow Direction ◽

Surface Flow ◽

Tropical Storm ◽

Mean Flow ◽

Boundary Layer Structure ◽

Stratiform Precipitation ◽

Wind Profiles

Abstract Detailed observations of boundary layer structure were acquired on 14 September 2001, prior to and during the landfall of Tropical Storm Gabrielle. The Mobile Integrated Profiling System (MIPS) and the Shared Mobile Atmospheric Research and Teaching Radar (SMART-R) were collocated at the western Florida coastline near Venice, very close to the wind center at landfall. Prior to landfall, the boundary layer was rendered weakly stable by a long period of evaporational cooling and mesoscale downdrafts within extensive stratiform precipitation that started 18 h before landfall. The cool air mass was expansive, with an area within the 23°C surface isotherm of about 50 000 km2. East-northeasterly surface flow transported this cool air off the west coast of Florida, toward the convergent warm core of the Gabrielle, and promoted the development of shallow warm and cold fronts that were prominent during the landfall phase. Airflow properties of the boundary layer around the coastal zone are examined using the MIPS and SMART-R data. Wind profiles exhibited considerable temporal variability throughout the period of observations. The stable offshore flow within stratiform precipitation exhibited a modest jet that descended from about 600 to 300 m within the 20-km zone centered on the coastline. In contrast, the onshore flow on the western side of the wind center produced a more turbulent boundary layer that exhibited a well-defined top varying between 400 and 1000 m MSL. The horizontal variability of each boundary layer is examined using high-resolution Doppler radar scans at locations up to 15 km on either side of the coastline, along the mean flow direction of the boundary layer. These analyses reveal that transitions in boundary layer structure for both the stable and unstable regimes were most substantial within 5 km of the coastline.

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