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Overview of The International H 2 O Project (IHOP_2002)

Overview of The International H 2 O Project (IHOP_2002). David B. Parsons and Tammy Weckwerth Co-lead Scientists NCAR/ATD. Motivation and research goals Preliminary highlights Impacts and role of profiling. GENERAL MOTIVATION. Overall Goals.

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Overview of The International H 2 O Project (IHOP_2002)

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  1. Overview of The International H2O Project (IHOP_2002) David B. Parsons and Tammy Weckwerth Co-lead Scientists NCAR/ATD • Motivation and research goals • Preliminary highlights • Impacts and role of profiling

  2. GENERAL MOTIVATION

  3. Overall Goals • Improved understanding and prediction of warm season rainfall (0 –12 h forecast) • Improved characterization of the time varying 3-D distribution of water vapor • Four overlapping research components • Convective initiation • Quantitative precipitation forecast • Atmospheric Boundary Layer • Instrumentation (optimal mix)

  4. Isentrophic Airflow and 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)

  5. IHOP Summary: 13 May to 25 June • >200 Technical participants from the U.S., France, Germany and Canada • ~2500 additional soundings • > 50 instrument platforms, 6 aircraft, 45 IOPs • 268 h of airborne water vapor lidar measurements • 76 h of airborne satellite evaluation measurements (S-HIS and NAST) • Dedicated GOES-11 data

  6. IHOP_2002

  7. IHOP Aircraft

  8. Convective Initiation Flight Plan

  9. Mobile Mesonet, Smart-R radar and Control Center

  10. Convective Initiation of a flash flood

  11. Wyoming Cloud Radar (WCR) reflectivity profile above flight level, along a 22 km long transect from ESE to WNW on 24 May 2002 in northern Texas.

  12. 1ST Session Gentry et al. (GLOW) Geerts and Maio (bugs) Yu et al. (MAPR-RIM) 2nd Session Feltz et al. (AERI) Flentje et al. (DLR DIAL on IHOP ferry flights) Session 6 Flamant et al. (bore) Koch et al. (bore) Whiteman et al. (SRL) Browell et al. (LASE) Demoz et al. (Dryline) Hardesty et al. (Doppler and DLR DIAL) Kiemle et al. (DLR DIAL) Di Girolamo (Raman) RESEARCH HIGHLIGHTS

  13. Session 6 (cont.) Tarniewicz et al. (GPS, DIAL, NWP) Lhomme et al. (LEANDRE DIAL) Van Baelen et al. (GPS) Wang (radiosonde and lidar) Behrendt et al. (DIAL intercomparison) Knuteson et al. (HIS) Session 7 Schwemmer et al. (HARLIE) RESEARCH HIGHLIGHTS

  14. 1st Research Example • Radar Refractivity- • Current nowcasting systems use radar fine lines detected by reflectivity, future systems will rely heavily on radar refractivity!! • Developed by Fred Fabry (McGill) • Deployed on the NCAR’s S-band radar (S-Pol) • Analysis by Fabry, Weckwerth, Pettet et al.

  15. Radar Measurements of Refractive Index 4πf —— r n c Target phase: Ф(r) = 2πf ttravel(r) = For fixed targets, phase will change as n changes.

  16. Rapid moistening Storm Outflow Wet Real Time Display Example 60 Diurnal cycle (mostly) Dry Wet

  17. 10 5 0 IHOP Examples: Dry-Line Genesis 7º 11º+ P3 Broad Td gradient; Hints of convergence

  18. Fine line appears 10 5 0 IHOP Examples: Dry-Line Genesis 20:51 P3 Tight gradient moving Tightening gradient

  19. Dry line splits IHOP Examples: Dry-Line Evolution …As dry line moves west To join back after…

  20. Refractivity: One Day After Heavy RainfallAircraft In-situ data Northern edge of aircraft track Ts=45, Theta60=307, q60 = 8.5 Southern edge of aircraft track Ts=32, Theta60=306.2, q60 = 11 Weckwerth and LeMone also Fabry

  21. 2nd Research Example GOAL: Attempt to answer the conundrum of why there is a nocturnal precipitation maximum over the Southern Great Plains when the convective stability should be less favorable. Result: Undular bore-like disturbances, thought to occur over this region on occasion, are common, tigger new convection and create a mesoscale environment favorable for deep convection.

  22. IHOP_2002 Sounding Western OK1730 pm LST CAPE CIN

  23. Water Vapor: 20 June

  24. BORE Example From MAPR 4 June

  25. “Surface”-based Parcel 20TH June Unstable, capped env. 1730 pm Dramatic stabilization, expected due to radiational cooling ! 0301 am Very stable

  26. “Surface” and Inversion Parcels 0301 am 1730 pm 1730 pm 0301 am Opposite trends In fact the parcels are easier to convect than during the day!!!! Instability increases during the night

  27. 20 June: 3 am Sounding Dramatic moisture increase

  28. 2 June Bore/Wave Event

  29. BORE Example From MAPR 4 June Post height Pre-bore height

  30. 12 June Bore/Wave Event

  31. 13 June Bore/Wave Event

  32. 21 June Bore/Wave Event

  33. 25 June Bore/Wave Event

  34. Bore Height Displacements Scattering Layer Height (km) Reference slope of .5 m/s Reference slope of .5 m/s Time (mins)

  35. Bore Summary • Bore/wave disturbances are ubiquitous over this region at night when convection is present. ~26 event. Most events occur at the end of LLJ moisture return periods (when convection is present) • These disturbances can promote intense lifting with net displacements of up to ~1-2 km. They creating a deeper moist inflow and favorably impact stability. Some CI occurs. Peak vertical motions are >1-2 m/s. • Surface radars undercount bore/wave events (at a fixed location), since the lifting can be limited to heights above the PBL. Thus, ~26 events is likely an undercount! • These disturbances are (almost) always initiated by convection (slight evidence for both a secondary evening and larger nocturnal initiation). Later in the program and initiation is not by dry fronts. • Typical spacings of waves ~10-14 km, surface evidence (pressure disturbances (.25 – 1.5 hpa) with some closed circulations, typical duration is ~3-6 hrs with mesoscale to synoptic coverage areas.

  36. 3rd Research Example:more rawinsonde controversy

  37. SUCCESS (?) • Significant impact on current conferences • 23 papers at the recent Int’l Conference on Radar Meteorology (August in Seattle) • ~20 papers at this meeting • Already see points where we will likely impact operational prediction in US (sonde transition work and radar refractivity) • Already see strong research on the atmosphere and instrument techniques, but assimilation work for NWP is yet to come

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