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3-D Radar Mosaic and Initial Q2 Development Plans. Jian Zhang 1 , Ken Howard 2 , and Steve Vasiloff 2 1 University of Oklahoma, Norman, OK 2 National Severe Storms Lab, Norman, OK. Outline. NMQ Components Overview Single Radar Process 2-D Radar Mosaic 3-D Radar Mosaic
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3-D Radar Mosaic and Initial Q2 Development Plans Jian Zhang1, Ken Howard2, and Steve Vasiloff2 1University of Oklahoma, Norman, OK 2National Severe Storms Lab, Norman, OK Q2 Workshop, Norman, OK
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
NMQ Overview Flowchart Radar Ingest & QC Satellite 2D/3D Radar Mosaic Hydro Model* Rain Gauge QPF QPE Sfc Obs & Sounding Precip Products Mosaic Products Hydro Products Lightning Verification Users Model
NMQ Overview Flowchart Radar Ingest & QC Satellite 2D/3D Radar Mosaic Hydro Model* Rain Gauge QPF QPE Sfc Obs & Sounding Precip Products Mosaic Products Hydro Products Lightning Verification Users Model
NMQ Philosophy • An open R&D system • Dynamic enhancements/improvements to scientific components • Real-time 24/7 testing and evaluation on CONUS domain to address real-world problems • A real-time verification system • Cost-effective algorithms for operational benefits • Incorporation of new data as they become available • A common framework for joint scientific research and development
Data Ingest • Radar • WSR-88D, level-II and level-III (140+radars) • Canadian radar network (~35 radars, efforts undergoing) • TDWR (ongoing, limited data availability) • CASA/gap-filling radars (future) • Dual-pol radar data (future)
Data Ingest (Cont.) • Satellite • GOES IR imagery data (Tb) • For QC and radar-satellite QPE • GOES sounder data (ECA) • For QC • Other (GOES multi-spectral, exploring) • Auto Estimator (efforts undergoing) • GMSRA (future) GOES Multi-Spectral Rainfall Algorithm • SCaMPR (future) Self-Calibrating Multivariate Precipitation Retrieval
Data Ingest (cont.) • Rain Gauge • NCEP/USGS hourly gage data • OK mesonet • Additional gage networks (mesowest, LCRA, prism) • Other?
Data Ingest (cont.) • Model (RUC 20km, hourly analysis) • Upper Air Sounding • Lightning • Surface Observations (ASOS) (future) • Other?
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
Single Radar Process • Reflectivity QC (dynamically evolving effort!) • Noise filter • Sun beam filter • Terrain based QC (hybrid scan) • Horizontal texture and vertical structure based QC • Temporal continuity based QC Satellite based QC • Satellite based QC • Dual-pol data (future) • Velocity Dealiasing
Temporal Continuity QC To remove the hardware testing pattern: Check sudden increase in echo coverage between consecutive volume scans
Single Radar Process (cont.) • Reflectivity climatology • Brightband Identification • Precipitation typing • (1-good strat rain; 2- bad strat rain; 3-good strat snow; 4- bad strat snow; 5-mixed phase; 6-convective). • Hybrid scan reflectivity and the associated height • Composite reflectivity (QC and UnQC) and the associated height • Vertical Profile of Reflectivity (VPR) • VPR-adjusted hybrid scan reflectivity
Convective Precip Flags Composite Reflectivity Convective/Stratiform Segregation • dBZ > 50 in any bin or, • dBZ > 30 at temperatures < -10 C or, • 1 lightning flash
Bright Band Identification (BBID)(Gourley and Calvert, 2003, WAF) • 3-D Reflectivity Field • Find Layer of Higher Reflectivity • Vertical Reflectivity Gradient • Spatial/Temporal Smoothing
Precipitation type classification • Stratiform rain/snow • Composite refl. • Precip. type
Single Radar Process (cont.) • 3-D Single Radar Cartesian (SRC) Grid reflectivity (QC’d and UnQC’d) • 3-D SRC reflectivity (QC’d with VPR gap-filling) • Multi-scale storm tracking • 3-D SRC grid with synchronization
Single Radar Cartesian Grid R = 460km for coastal radars and 300km for other radars. X R Horizontal grid (~1km x 1km) Vertical grid (31 levels)
o + o o o + o o 3-D Spherical to Cartesian Transformation(Zhang et al. 2005, JTECH) No BB: Vertical linear interpolation No BB BB exists: Vertical and horizontal linear interpolation BB
Convective Case1: RHI, 263° Raw Interpolated
Stratiform Case 2: RHI, 0° Raw Interpolated
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
2-D Radar Mosaic • Composite reflectivity (QC’d and UnQC’d) and associated height • Hybrid scan reflectivity (QC’d, with and without VPR-adjustment) • Precipitation type • Radar coverage maps (spatial and temporal) • Layered composite reflectivity (e.g., the lowest 4 tilts)
Strat Rain (good) Convective (good) Bright Band (bad) Frozen (bad) 2D Precipitation Type Mosaic
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
3-D Radar Mosaic • 3-D multi-radar mosaic grid • QC’d • UnQC’d • QC’d with VPR gap-filling • 2-D derived products: • Composite reflectivity and the associated height • Hybrid scan reflectivity and associated height • Hail products (SHI, POSH, MEHS) • VIL and VILD • ETOP • Layered composite reflectivity
Cross Sections from 3-D Mosaic Dallas Hail Storm, 5/5/1995
Outline • NMQ Components Overview • Single Radar Process • 2-D Radar Mosaic • 3-D Radar Mosaic • Initial Q2 Development Plans • Outlook
Q2 Components • Radar QPE • Satellite QPE • Rain gage QPE • Multi-sensor QPEs • Radar+satellite (& model and sounding) • Radar+gage • Radar+satellite+gage
Radar QPE • Rain rate • Derived from: • Hybrid scan reflectivity from 3-D radar mosaic (QC’d, with and without VPR gap-filling) • Layer composite reflectivity of the lowest 4 tilts (from 2D radar mosaic) • Different Z-R relationships based on 2D mosaic precip type field • 1km x 1km, update every 5 min • Accumulations (1- to 72-h or longer)
Z-R relationships Oklahoma Convective Oklahoma Stratiform Taiwan
Satellite QPE • Products from existing algorithms: • Hydro (Auto) Estimator • GMSRA • SCaMPR
Rain Gauge QPE • Individual stations • Objective analysis -- gridded gage products (e.g., ADAS) • Issues: • Bad data • Spatial representativeness of gage obs • Non-uniform and sparse gage distributions • Terrain effects • Real-time latency
Radar-satellite QPE • Radar rain rate - satellite Tb regressions • Multiple regressions -- one for each weather regimes • Initial weather regimes are defined by: • Surface temperature zones (hourly RUC surface analysis) • Regression using data pairs within a running hourly window • Rain rate averaged for each 1 deg Tb bin • Derive a dynamic exponential regression to the data in a least square fit sense • Various rules to prevent an ill-conditioned regression
Radar-satellite QPE (Contd.) • Satellite rain rate • Apply regression curves to the Tb field in each weather regimes and obtain rain rate • Distance weighted mean across boundaries between different weather regimes • Use rain/no-rain mask (defined by radar obs and satellite) • Accumulations (1-72h)
Surface Temp Regression Equation Satellite CTT Satellite/Radar Regression Regresses co-located satellite Tb with stratiform R from radar. One for each weather regimes. Radar Rainrate Updates regression curves hourly and purges old data
Surface Temp Regr. Eqn Q2 Rainfall Rate Satellite CTT Generating Multi-sensor Rate Regression parameters are used to calibrate cloud-top temperature field by supplying precipitation rates
Radar-gage QPE • Pre-defined bias regions (radar umbrella? basins? weather regimes?) • Regional radar/gage bias adjustment • Compute mean radar/gage bias for each bias region • Adjust radar QPE using the bias • Smoothing over the boundaries between bias regions • Point radar/gage bias adjustment • Compute radar/gage bias at each gage station • Objective analysis of the point biases • Adjust radar QPE using the gridded bias field • Bias is based on hourly accumulation • Adjustment is performed in real-time dynamically