Overview of USWRP’s
International H2O Project
(IHOP_2002)
David B. Parsons and Tammy Weckwerth
NCAR/ATD
• IHOP facts and research goals
• Preliminary highlights
• Modeling plans
IHOP_2002 Hypothesis
Improved measurements of water
vapor will lead to a corresponding
improvement in our ability to predict
convective rainfall amounts.
Note: 0-12 h forecasts in an environment where
the dyamics is well characterized.
Isentrophic Airflow and IHOP Sounding
Domain
Isentropic streamlines (37 C) for 2330 UTC 4 May 1961. The dashed lines are
isobars at 100 hPa intervals (from Carlson and Ludlam 1968)
Some Research Goals Directly Relevant to QPF
• Improved understanding and prediction of convective onset.
• Determine the degree of improvement in forecast skill that occurs
through improved characterization of the water vapor field (06/12 h) in an environment where the dynamics are relatively well
captured.
• Improved understanding and treatment of the relationship
between atmospheric water vapor, soil moisture, surface fluxes
and boundary layer processes.
• Improved assimilation of water vapor measurements for warm
season events (including satellite data).
• Determine the future optimal mix of satellite, ground-based and
surface water vapor measurement strategies for warm season
rainfall.
IHOP Summary: 13 May to 25 June
• >200 Investigators and technical participants
• ~2500 additional soundings
• > 50 instrument platforms, 6 aircraft, 36 IOPs
• 268 h of airborne water vapor lidar measurements
• 76 h of airborne satellite evaluation measurements (SHIS and NAST)
• Dedicated GOES-11 data
S-Pol Refractivity Retrieval
dryline
• variations in q, T and p
• boundary detection
• advection
• QPF, CI, ABL and inst
•Lower ABL
warm/dry
dryline
cool/moist
Refractivity: One Day After Heavy Rainfall
Aircraft In-situ data
N: Ts=45,Theta60=307, q60 = 8.5
S: Ts=32,Theta60=306.2, q60 = 11
Evolution
of the
dryline
Nocturnal Convection
An example of
a nocturnal
undular bore
Example
of
a
Nocturnal
Undular
Bore
Example of a Doppler
Nocturnal
Undular
Velocity
Bore
Bore Example (Radar RHI)
BORE
Example
From
MAPR
4 June
Water Vapor: 20 June
Sounding Susceptible to PBL-Based Convection
DVN (0000 UTC 9/12/2000)
Sounding Susceptible to Elevated Convection
GRB (0000 UTC 9/12/2000)
From Trier et al. 2002, abstract 130
Convective
Initiation
of a flash
flood
Some Closing Thoughts
• Some spectacular convective initiation cases, but often
highly dependent on forecaster refinement of model
output. Also many null cases (50-50?).
• Nocturnal convection is far different than previously
thought (bores and jet decoupling).
• Potential utility of radar refractivity and high resolution
radar composites.
• Water vapor vertical cross-sections useful for determining
changes in capping inversions for forecasters. (SPC
forecaster comment)
• Spaced antenna profilers can easily detect intense
mesoscale air motions.
• Scientist/forecaster interactions were extremely valuable.
• Modeling work has only just begun.
Model, Assimilation and Nowcasting Efforts2
•
•
•
•
•
•
•
10-km version of the ETA model (Gallus/U of Iowa)
ARPS non-hydrostatic model1 (Carr et al./CAPS-OU)
Operational RUC (Szoke & Brown et al./NOAA/FSL)
LAPS with MM5 & WRF (Koch et al./NOAA/FSL)
Non-hydrostatic CSU RAMS (Zeigler/NOAA/NSSL)
UW NMS (Mecikalski/UW)
MM5 mesoscale model (Lapenta/GSFC; Mecikalski/UW; Pinto et
al./NCAR)
• WRF mesoscale model (NCAR)
• CRAS mesoscale model (Diak/UW & Davis/Penn State)
• Interactive flash flood analyzer and rainfall autonowcaster (Holt et
al./NOAA/NESDIS)
• NCAR autonowcaster (Wilson et al./NCAR)
• NCAR Water Cycle Initiative Group (Cloud model to Community climate
model scales)
• ETA/WRF NCEP mesoscale branch (after data is cleaned up)
• __________________
1These efforts may move to the WRF model during the post-field phase.
2The research includes evaluation of current products, assimilation
research, forecasting, and predictability studies.