Goal for FY01 and FY02:
International H2O Project - 13 May to 30 June 2002
Investigators from the U.S. (NCAR, NOAA, NASA and university community (~12), France, German and Canada.
IHOP 2002 focused on the improved prediction of the timing, location, duration and magnitude of warm season convective rainfall.
Floods, especially flash floods, cause more deaths each year than tornadoes, hurricanes, lightning and wind storms (Doswell et al. 1996, USA Today 1999). Other serious human impacts.
Highest percentage of federal aid events are floods and flash floods. Significant property losses due to flash floods (>$5 billion per year, U.S. Army Corps of Engineer 1998).
The problem of flash floods and warm season convective damage is not a regional problem but one that national and international in scope.
It has been argued that improvements in QPF for non-flood situations will have significant economic and social benefit.
Extremely poor skill in predicting warm season heavy rainfall events and lack of recent improvement. Despite significant progress made in detecting and/or forecasting many other warm and cool season hazard.
IHOP 2002 focused on improved understanding and prediction of warm season convection through better characterization of the water vapor field.
Numerous mesoscale modeling studies [see IHOP 2002 overview document and Koch et al. (1997) for list] demonstrated that more accurate characterizations of the water vapor field led to significant improvements in forecasts of convective rainfall. The European Center tested the sensitivity of warm season forecasts to humidity measurements.
Predictions of convection with cloud models required very accurate water vapor measurements - accuracy that was often beyond our current operational measurement capabilities (Crook 1996).
The impact of variations in the low-level humidity on CAPE was well established as was the importance of CAPE and its ratio with the vertical wind shear on convective intensity and structure (see well known work of Mitch, Morris and others here at NCAR).
The project has four overlapping components:
Instrumentation. Contribute to determining the optimal mix of future water vapor measurement and assimilation techniques for research and operations. Evaluate current and future satellite sounding techniques
Convective Initiation. Improved understanding and prediction of where, when and why convection forms over the southern Great Plains.
Boundary layer. Understanding how boundary layer processes and surface characteristics lead to atmospheric heterogeneity and subsequently impact convective development and evolution. Improved treatment of boundary layer processes in numerical models of varying scales.
QPF. Determine the relative impact of improved water vapor measurements on skill in nowcasting and predicting convection.
Instrumentation. Have the participation of most sensor techniques utilized for water vapor and test performance in a convective environment. Use airborne measurements to mimic satellite based approaches.
Convective Initiation. Target airborne and ground-based measurements in region where convection is predicted to occur.
Boundary layer. Airborne mapping of water vapor and water vapor transport through the boundary layer plus enhanced surface measurements.
QPF. Ground network of profiling sites plus mapping of the water vapor field by multiple aircraft.
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