Hot Items 2004National radar mosaic and QPE project
NSSL's Worldwide Integrated Sensor Hydrometeorology (WISH)team has taken on an ambitious project to seamlessly mosaic all 130 NWS and Department of Defense (DoD) radars across the U.S. The mosaic will provide the first high-resolution depiction of storms and quantitative precipitation estimation (QPE) products from coast-to-coast in real-time. Additional users for the national mosaic will include FSL and NCEP.
Mosaic
The ability to integrate data from multiple radars at their fullest resolution
into a single framework was not without significant challenges. The 3-D multi-radar
reflectivity analysis and mosaic scheme is the result of nearly five years
of research and development. The resulting scheme includes quality control,
an adaptive objective analysis scheme, and a distance weighted mosaic technique.
It takes into account different spatial scales of convective and stratiform
weather echoes and reconstructs 3-D reflectivity analyses using different
interpolation techniques. The code has gone through extensive optimization
to assure a high computational efficiency and operational applicability.
The 3-D mosaic has been running in real-time in the FAA Corridor Inegrated Weather System (CIWS) domain since August 2002. The CIWS 3-D mosaic has 1 km x 1 km resolution and 21 vertical levels ranging from 1 km to 17 km above mean sea level. The mosaic combines base level reflectivity data from 32 radars with a five minute update cycle. Other product development teams at NCAR and MIT/LL have been using the CIWS mosaic data in convective and wintertime numerical weather modeling.
QPE-SUMS
Challenges in radar-based QPE were discovered by NSSL scientists by examining
precipitation products for cool season cases over the complex terrain of
Arizona. Issues with beam blockages by terrain and bright band effects limited
the value of the products. The Quantitive Precipitation Estimation and Segregation
Using Multiple Sensors (QPE-SUMS) algorithm, which runs in conjunction with
the 3-D mosaic, was designed the address these issues by integrating satellite
and model data in its scheme. Today, it continues to provide improved basin-wide
rainfall and snow-water equivalent estimates to the Salt River Project for
the purpose of managing large-scale watersheds. In recent years, the 3-D
mosaicking and QPE-SUMS software has been deployed in several other regions
in the U.S. and around the world. Data quality control and estimation techniques
have been improved from these experiences to accommodate precipitation from
typhoons, hurricanes, extratropical cyclones and mixed-phase events.
The Next Phase
The WISH group is taking its entire project to the next phase this spring.
Up to now, the high-resolution radar data (i.e. Level II data) that the algorithms
use to operate were available for only select radars in the U.S. In 2004,
the Collaborative Radar Acquisition Field Test (CRAFT) network will include
all NWS and several DOD radars, thus enabling the WISH group to extend its
software deployment to the whole U.S. The National Mosaic and QPE-SUMS (NMQ)
products will be available every five minutes on a 1 x 1 km grid covering
the conterminous U.S.
This project has potential benefits to government, university and private sector users. The resolution and accuracy of the precipitation products will be a natural fit-in to NWS's Flash Flood Monitoring and Prediction (FFMP) project, for which NSSL provided delineated basins for the entire U.S. Moreover, the QPE-SUMS products will be useful for verifying quantitative preciption forecasts that are being producted at higher and higher resolution.
This project provides the WISH group an impetus to partner with other agencies and develop improved products collaborately during this expansion. NSSL will be working with the Bureau of Reclamation in order to adopt QPE strategies they've developed for snowfall estimation. In addition, satellite-based techniques are being integrated through a collaborative effort with the NOAA National Environmental Satellite, Data, and Information Service. the 3-D mosaic will become 4-D through development of a new temporally weighting scheme that retains high-resolution storm structure from temporally-offset radar observations and minimizes any dampening effects on storm intensities. Several severe storm monitoring and QPE-SUMS products will operate off these new mosaicked reflectivity fields. The WISH group plans to make the NMQ products available to NWS forecaters at local offices and river forecsat centers.
The WISH team has always been at the forefront of technologies related to high-resolution radar data mosaicking and QPE, and this new project is the next step towards the NMQ goal.
4/28/2004