NEW |
PACJET 2003 Site
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RESOURCES |
PACJET 2002 Site
GPS Realtime Water Vapor
GWINDEX
West Coast RUC
ETL Profiler Network
Press Materials
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BACKGROUND |
About Pacjet
CALJET Summary
Societal Impacts and User Input
Linkages to National Priorities
USWRP
Data Assimilation Implementation Plan
March 2001 Program Status Report
PACJET 2001 Poster
NSSL Briefing
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PROGRAM DOCUMENT |
PACJET and a Long-term Effort
to Improve 0-24 h West Coast Forecasts
Overview Poster
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RESEARCH PARTICIPANTS |
NOAA Research
ETL,
NSSL,
FSL,
AL,
CDC
National Weather Service Western Region
Eureka,
Hanford,
Medford,
Monterey,
Oxnard,
Portland,
Reno,
Sacramento,
San Diego,
Seattle,
CNFRC
Office of Marine and Aviation Operations
AOC
Naval Postgradute School
DRI CIASTA
CIRES
SUNY Stony Brook
National Centers for Environmental Prediction
EMC,
HPC,
MPC
National Environmental Satellite, Data
and Information Service
CIMSS,
CIRA
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OPERATIONAL FORECASTING COMPONENTS |
COMET Presentation
West Coast RUC
Aircraft Obs via AWIPS
GWINDEX Poster
Applications Development
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RESEARCH COMPONENTS |
Modeling Research Components
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RELATED EXPERIMENTS |
Winter Storm Reconnaissance (Central Pac.)
CRPAQS (CA Air Quality)
IMPROVE (Microphysics)
THORPEX (Synoptic Targeting)
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OBSERVING SYSTEMS |
AEROSONDE
NOAA P-3
Wind Profiler Network
Satellite Products
NOAA S-band Radar
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CONTACTS |
Program
Media Contacts
Webmaster
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PLANNING WORKSHOPS |
2001 - Monterey, CA
July 13-14 2000 (Boulder, CO)
July Workshop Agenda
September 1999 - Monterey, CA
1999 Planning Workshop Figures
June 1998 - CALJET
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Validation and Improvement of Forecasting Models
- Surface momentum and thermal fluxes
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PACJET will provide opportunities to evaluate and improve physics in
operational forecasting models related to property transport between
the surface and the air.
For example, quantitative precipitation
forecasts in the vicinity the US West Coast are sensitive to the water
vapor transfer that occurs horizontally (from offshore to coast) and
vertically (between the sea surface and the air). It has been
recognized that the capability of numerical models in describing water
vapor transfer at the air-sea interface is limited by insufficient
knowledge of physical property exchange between the surface and the
air associated with strong weather events.
When a weather system
approaches the coast, its interaction with the sea and coastal
topography is very dynamic. Offshore in light wind conditions, the
sea surface and air-sea interaction is relatively simple because there
is little wave breaking, but under high wind conditions or near the
coast, wave breaking, sea spray, surface currents, and differences
between wave and wind directions all contribute to the air-sea
interaction and create a complex challenge to modeling. On land, the
topography and land surface characteristics are highly irregular on
many spatial scales from meters to kilometers.
Properly simulating
the complex interaction of the weather system with the sea and the
coast is a major challenge in meteorology. PACJET will combine
airborne and ship-based flux measurements and will include intensive
wave observations. The intercomparison of airborne and ship measurements
require different assumptions about the spatial and temporal
sampling of fluxes. A similar
intercomparison will be performed on airborne scanning radar
altimeter measurements and ship borne measurements of waves.
- Cloud physics
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The skill of numerical models in fog and quantitative precipitation
forecasts near the US West Coast is limited by uncertainties in the
understanding and parameterization of cloud microphysics when moist
maritime air flow interacts with complex coastal mountains. Of
particular interest is the quantification from CALJET that warm rain
processes can produce rain rates in the coastal mountains that are
capable of producing flooding. PACJET will further explore this
phenomena using an enhanced observational approach. These results
will improve understanding of microphysical behavior, and will feed
back into parameterization testing.
- Using Ensembles in Quantitative Precipitation
Forecasting
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One approach to improve coastal storm and rainfall prediction is the
so-called ensemble prediction. This approach is based on the
assumption that the skill of a single deterministic model forecast is
limited by many uncertainties, particularly in initial conditions and
in model formulations, while the average skill of an ensemble of
different model predictions will be better than any of the individual
members. PACJET will provide comprehensive data sets that can be used
to evaluate different ensemble techniques.
- Assimilation of Targeted Observations
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It has been recognized that targeted observations in areas where
routine observations are not available can improve the accuracy of
weather prediction for a specific region and lead time.
However, many
questions remain.
- How best identify and sample a target?
- How large the impact can be?
- How sensitive the results are to the temporal and spatial scales of the observations?
- What are the best data assimilation approaches for ingesting the
targeted observations into numerical models?
PACJET will provide
observations that can be used for answering these questions. This
will be done in quasi-real time using parallel runs of key models,
including the MRF run at NCEP, an experimental version of the
RUC that
covers the eastern Pacific and is run at FSL, and a version of
MM5 run
at ETL. For each model, the difference between a run with and without
the experimental data will be calculated, and thus the impact of the
data on NWP will be assessed.
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