Doppler Weather Radar Research and Development
NSSL Project 2 – National Quantitative Precipitation Estimation Mosaic (formerly called Quantitative Precipitation Estimation and Segregation Using Multiple Sensors)
Funding Type: CIMMS Task II
Objectives
Develop a seamless high-resolution national 3-D grid of radar reflectivity
for data assimilation, model verification, and aviation product development;
develop automated multi-sensor QPE techniques at high spatial and temporal
resolutions and accuracy for use in operational flash flood monitoring
and prediction and water resource management.
Accomplishments
The 3-D high-resolution national radar reflectivity mosaic has been running
at NSSL in real-time since June 2006. The software was transferred
to NCEP for operational implementation during 2006. Meanwhile, the
3-D national radar mosaic at NSSL continues to serve as a prototype
system and as a testbed for new research and development activities.
Research and development this year included the integration of Canadian
radar network (5-cm radar) with the WSR-88D network (10-cm radar) and
creation of a gap filling technique based on the vertical profile of
reflectivity (VPR). The figure below shows example horizontal cross-sections
of reflectivity from 3-D mosaic grids with and without the Canadian
radars. The Canadian radar network provides better coverage of this
precipitation system at all altitudes. The additional coverage provided
at the lower levels (panels b and d) is significant because of the
Canadian radar’s lower elevation angle (0.3°) in comparison
to the WSR-88D (0.5°). This could potentially improve quantitative
precipitation estimation (QPE) in the Great Lakes region. At upper
levels images (panels f and h) seamless mosaicing is shown between
the WSR-88D and Canadian radars. The seamless 3-D reflectivity grid
can be beneficial to aviation weather applications such as convective
and winter weather monitoring and prediction as well as for icing condition
analysis across the U.S./Canada border.
A new warm season radar-based QPE algorithm has been developed based on the 3-D radar mosaic produced through the Q2 initiative (Vasiloff et al. 2007). It was evaluated over 20 events during March 2007 using rain gauge data and NCEP Stage IV precipitation products. The performance of the new algorithm is comparable to the Stage IV for most events with the exception of in mountainous regions of California and the Pacific Northwest. The results are very encouraging since this radar-based QPE is a high-resolution (1-km versus 4-km for Stage IV) and rapidly-updating (every 5-min versus every hour for Stage IV) product. It has the potential for improving flash flood detection.
This project is ongoing.
Publications
Langston, C., J. Zhang, and K. Howard, 2007: Four-dimensional dynamic radar
mosaic. J. Atmos. Oceanic Technol., 24, 776-790.
Vasiloff, S., D.J., Seo, K. Howard, and J. Zhang, 2007: Q2: Next generation QPE and very short-term QPF. Bull. Amer. Met. Soc., accepted. Yang, H., J. Zhang, and C. Langston, 2007: Synchronization of radar observations with multi-scale storm tracking. Adv. in Atmos. Sci. in press.
Zhang, J. and S. Wang, 2006: An automated 2-D multi-pass Doppler radar velocity dealiasing scheme. J. Atmos. Oceanic Technol., 23, 1239-1248. Zhang, J., C. Langston, and K. Howard, 2007: Bright band identification based on vertical profiles of reflectivity from the WSR-88D. J. Atmos. Oceanic Technol., in press.
Zhang, J., K. Howard, and S. Wang, 2006: Single radar Cartesian grid and adaptive radar mosaic system. 12th Conf. on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, Amer. Meteor. Soc., CD-ROM 1.8.
Zhang, J., C. Langston, K. Howard, and B. Clarke, 2006: Gap-filling in 3D radar mosaic analysis using vertical profile of reflectivity. 12th Conf. on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, Amer. Meteor. Soc., CD-ROM 1.9.
Zhang, J., C. Langston, and K. Howard, 2006: Vertical profiles of reflectivity for different precipitation regimes. Proc., 4th European Conference on Radar in Meteorology and Hydrology. Barcelona, Spain, 225-228.
Yang, H., J. Zhang, C. Langston, and S. Wang, 2006: Synchronization of multiple radar observations in 3-D radar mosaic. 12th Conf. on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, Amer. Meteor. Soc., CD-ROM 1.10.
Horizontal cross sections at 0.5 (row 1), 1.0 (row 2), 3.0 (row 3), and 5.0 (row 4) km above mean sea level from the 3- D mosaic grid with two WSR-88Ds (KDLH and KMVX) (left column) and from the 3-D mosaic grid with three additional Canadian radars (XWL, XDR, and XNI) (right column).