Deng, Aijun, David Stauffer, Brian Gaudet and Glenn
Hunter, Penn State University, USA
To support
time-sensitive, high-resolution modeling applications such as emergency
response and aviation, Penn State has developed a rapidly-relocatable
high-resolution forecast/nowcast system based on WRF. Penn State has been using the system for many applications,
all of which use the WRF multiscale FDDA capabilities developed and implemented
by Penn State. These applications
include 1) the Defense Threat Reduction Agency (DTRA) relocatable on-demand
forecast system (ROFS), currently used at DTRA to support the various
applications related to hazard prediction and assessment; 2) the NEXGEN airport
forecast system (NGAFS) that is initialized hourly using either the Rapid
Update Cycle (RUC) or the Rapid Refresh (RR) with partial cycling of land
surface fields, recently developed under NOAA sponsorship to improve
high-resolution forecasts for airports, and also has potential to be used for
wind energy forecasts; 3) a WRF
realtime forecast system that predicts the 4-D wind fields that was used to
support the flight operation of the Penn State team that won first prize at the
2011 Green Flight Challenge competition; and 4) a time-lagged WRF-Chem realtime
forecast/monitoring system used to support the CO2 monitoring study during the
World Economic Forum Annual Meeting 2012 over Davos, Switzerland.
Some modeling results
from these applications will be presented, with special focus on the results of
the NGAFS that was evaluated with the historic snowstorm that occurred in 29
October 2011. In this case a major
snowstorm over the New York City area terminals disrupted air traffic, and the
timing of the transition from rain to snow turned out to be a difficult problem
that was not well predicted.
Short-term dynamical forecasts using NGAFS were created using nested
domains with 9-km, 3-km and 1-km grid spacings over the New York City area
terminals. The system was
configured to run a 3-h pre-forecast data assimilation followed by a 6-12 h
forecast every hour, The WRF cold-start initial conditions and lateral boundary
conditions were provided by the 13-km operational RUC data. It was found that NGAFS was able
to reasonably predict the timing of the transition from rain to snow over the
airports, and the sensitivity experiments indicated that the assimilation of
Meteorological Assimilation Data and Ingest System (MADIS) surface and Aircraft
Communications Addressing and Reporting System (ACARS) data was particularly
beneficial.