Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE...
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Transcript of Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE...
![Page 1: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/1.jpg)
Orographic Precipitation Enhancement in Midlatitude
Baroclinic Storms: Results from MAP and IMPROVE II
Robert A. Houze and Socorro Medina
![Page 2: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/2.jpg)
Precipitation min on crest of Alps, max on lower slopes
20-year Alpine Autumn Precipitation Climatology
(rain gauge analysis by Frei and Schaer 1998)
![Page 3: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/3.jpg)
Major issue
Understand HOW microphysical processes are invigorated to produce quick and efficient orographic
enhancement in windward side flow
![Page 4: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/4.jpg)
The Cascade Project(Hobbs et al. 1973, Hobbs 1975)
Low concentration (large particles)
Liquid Water ContentStreamlines
Trajectories of ice particles growing by deposition and riming
High concentration (small particles)
![Page 5: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/5.jpg)
What microphysical processes can grow precipitation particles quickly?
Coalescence
T > 0 deg C
Aggregation Riming
T < 0 deg C
“Accretion”
![Page 6: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/6.jpg)
How can the airflow make the accretion processes more active?
(Smith 1979)
“Cellularity”
accretion
![Page 7: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/7.jpg)
Potentially unstable upstream flow: MAP IOPs 2b, 3, and 5
![Page 8: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/8.jpg)
IOP2b
IOP3
IOP5
Equivalent Potential Temperature
Milan sounding
12Z 03 Oct 9900Z 26 Sep 9912Z 20 Sep 99
![Page 9: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/9.jpg)
Stable cases: IMPROVE II Case 11
MAP IOP8
![Page 10: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/10.jpg)
IMPROVE II Experimental Area26 November-22 December 2001
PA
CIF
IC O
CE
AN
![Page 11: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/11.jpg)
IMPROVE II Case 11: 13-14 December 2001MM5 12 h forecast 500 mb height, wind, and temperature
Valid 00 UTC 14 Dec 01
![Page 12: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/12.jpg)
IMPROVE II Case 11Upstream soundings
IMPROVE II Case 11Upstream Soundings of equivalent potential temperature
![Page 13: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/13.jpg)
IMPROVE II Case 113-hour Mean Radial Velocity
Horizontal distance (km)
Hei
ght
(km
)
S-Pol radar
ESE
![Page 14: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/14.jpg)
IMPROVE II Case 113-hour Mean Reflectivity
Horizontal distance (km)
Hei
ght
(km
)
S-Pol radar
ESE
![Page 15: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/15.jpg)
IMPROVE II Case 11Polarimetric Particle Identification over 3 hours
P3 aircraft data
Horizontal distance (km)
Hei
ght
(km
)
S-Pol radar
large aggregates and/or graupelmelting snow
weak echo snow(high dBZ, low ZDR)
(high dBZ, high ZDR)
(low dBZ, low ZDR)
ESE
![Page 16: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/16.jpg)
Reflectivity
IMPROVE II NOAA/ETL S-band Radar13-14 December 2001
![Page 17: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/17.jpg)
IMPROVE II NOAA/ETL S-band Radar13-14 December 2001
Radial Velocity
Ri0.25
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Time series at
McKenzie Bridge during
IMPROVE II Case 11
Shear at0.7 - 3.0 km
(profiler)
Radialvelocity
(VP S-band)
Min radialvelocity at
2-3 km(VP S-band)
Occurrence of graupel &/or aggregates
(S-Pol)
![Page 19: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/19.jpg)
IMPROVE II Case 11Track of P3 aircraft & S-Pol reflectivity at 1.5 deg elevation
160 km
![Page 20: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/20.jpg)
1.6 mm
9.6 mm
IMPROVE II Case 11Ice particle imagery from P3 aircraft
![Page 21: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/21.jpg)
Stable cases:MAP IOP 8
![Page 22: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/22.jpg)
Equivalent Potential Temperature
IOP8
Milan sounding
18Z 20 Oct 99
![Page 23: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/23.jpg)
MAP IOP834-hour Mean radial velocity
S-Pol radar
NW
![Page 24: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/24.jpg)
MAP IOP834-hour Mean Reflectivity
S-Pol radar
NW
![Page 25: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/25.jpg)
MAP IOP8Polarimetric Particle Identification over 34 Hours
S-Pol radar
weak echo snow (low dBZ, low ZDR)
melting aggregates (high dBZ, high ZDR)
NW
![Page 26: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/26.jpg)
MAP IOP8Reflectivity from vertically pointing S-band radar
at Locarno Monti
Time UTC
Hei
ght
(km
)
OPRA radar
Yuter & Houze 2003
![Page 27: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/27.jpg)
Heavy rain
0°CTUR
BULENC
E
Microphysicalenhancement
Conceptual model for orographic precipitation enhancement in stable, sheared upstream flow
AggregationRiming
Coalescence
![Page 28: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/28.jpg)
TURBUL
ENCE
Conclusions
Low-level growth by coalescence and/or riming is needed to make precipitation fall out quickly on lower slopes
Cellularity is required to make the coalescence and/or riming occur
Cellularity may occur by EITHER release of potential instability OR by turbulence in stable flow
In stable flow, cellularity is a manifestation of turbulence in sheared flow rising over the terrain. Cells in stable flowfavor particle growth by
accretion have updrafts >1-3 m/scontain aggregates and/or
graupelenhance precipitation
on lower slopes
![Page 29: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/29.jpg)
![Page 30: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/30.jpg)
Mixed case:MAP IOP 14
![Page 31: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/31.jpg)
Equivalent Potential Temperature
IOP14
Milan sounding
00Z 4 Nov 99
![Page 32: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/32.jpg)
MAP IOP14Mean wind shear from Lonate profiler
Mean and SD over 16 hours
![Page 33: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/33.jpg)
MAP IOP1434-hour Mean radial velocity
S-Pol radar
NNW
![Page 34: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/34.jpg)
MAP IOP1434-hour Mean Reflectivity
S-Pol radar
NNW
![Page 35: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/35.jpg)
MAP IOP14Polarimetric Particle Identification over 34 Hours
S-Pol radar
weak echo snow (low dBZ, low ZDR)
melting aggregates (high dBZ, high ZDR)
NNW
![Page 36: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/36.jpg)
MAP IOP14Reflectivity from vertically pointing S-band radar
at Locarno Monti
Time UTC
Hei
ght
(km
)
OPRA radar
![Page 37: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/37.jpg)
![Page 38: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/38.jpg)
IMPROVE II Case 11Newport Wind Profiler Data
Mean and SD over 8 hours
![Page 39: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/39.jpg)
IMPROVE II Case 11McKenzie Bridge Profiler Data
Mean and SD over 8 hours
![Page 40: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/40.jpg)
MAP IOP8Mean wind shear from Lonate profiler
Mean and SD over 34 hours
![Page 41: Orographic Precipitation Enhancement in Midlatitude Baroclinic Storms: Results from MAP and IMPROVE II Robert A. Houze and Socorro Medina.](https://reader035.fdocuments.net/reader035/viewer/2022070415/56649ed95503460f94be705e/html5/thumbnails/41.jpg)
“Even if we accept the idea that large-scale orographic lifting can cause some release, it is … surprising in light of the difficulties in forming precipitation-size particles, to find release efficiencies of 70% to 100%, … Is it possible to convert such a high fraction of the condensed water into precipitation?”
Ron Smith (1979)
Major issue
Understand HOW microphysical processes are invigorated to produce quick and efficient orographic
enhancement in windward side flow
A Microphysical Question