Scientific Objectives and Required Facilities

Socorro Medina, Robert Houze, and Stacy BrodzikTIMREX Planning Meeting, Tainan, Taiwan, 9 November 2007

• Scientific Objectives– Investigate the vertical structure of precipitation over

Taiwan’s terrain– Investigate the structure of the terrain-modified airflow

• Required Facilities: S-Pol and upper-air soundings

• Highly desired: Vertically-pointing precipitation radar

Results from previous field experiments (MAP and

IMPROVE-2) to illustrate how S-Pol sectors of RHI scans were

used to accomplish similar objectives

Medina et al. (2007)

3-hour mean S-Pol reflectivity (1400-1700 UTC 28 Nov 2001 )

Cross-barrier distribution of time-averaged reflectivity as a function of height

Distance from the radar (km)Pacific Coastal R. Valley Cascades

Oregon Cascades

Cross-barrier distribution of S-Pol reflectivity aloft as a function of time - Maximum reflectivity (between 3-10 km)

Medina et al. (2007)

Te

rrai

n e

leva

tion

(km

)T

ime

(U

TC

) 30

20

10

0-10

dBZ

-20-30

Distance from radar (km)-150 -100 50 0 50 100 150

1.8

1.4

1.0

0.60.2

2118151209

0306

00

09

0306

0028

Nov

29 N

ov

Pacific Coastal R. Valley Cascades

Oregon Cascades

PBL flow adjacent to the terrain and embedded convection (S-Pol data)

Rotunno and Houze (2007)07-10 UTC 20 Sep 1999 mean

Radial velocity (m/s)Radial velocity (m/s)Low-level flowLow-level flowrising over terrainrising over terrain

Reflectivity (dBZ)Reflectivity (dBZ)Maximum echoMaximum echoon top 1on top 1stst peak of peak ofterrainterrain

Particle Type Particle Type (frequency of(frequency ofoccurrence)occurrence)Stratiform Stratiform background background punctuated punctuated by graupelby graupel S-Pol NNW

Distance from the radar (km)

Dry snow

Graupel

Wet snow

Alps

Alps

Evaluation of terrain-modified PBL flows simulated by numerical mesoscale models

08-11 UTC 21 Oct 1999 mean

Time-averaged observed radial Time-averaged observed radial velocity (m/s) (S-Pol)velocity (m/s) (S-Pol)

Time-averaged simulated radial Time-averaged simulated radial velocity (m/s) (MESO-NH) velocity (m/s) (MESO-NH)

S-Pol NW Distance from radar (km)

Alps Alps

S-Pol NW Distance from radar (km)

Alps

Vertically pointing radar dataReflectivity (dBZ)

Time

Radial velocity (m/s)

Houze and Medina (2005)

Other requirements

• Desk space for two people in the Operation Center (OPS) or for one person at the OPS and one person at the S-Pol site (depending on how much data can be transmitted from S-Pol to OPS)

• Internet access