US intrsumentation S-Pol-Ka and DOWs

US intrsumentationS-Pol-Ka and DOWs

Sabine GökeDept. of Atmospheric Sciences, University of Illinois, Champaign-Urbana, USA

COPS meeting, 10-11 April 2006

S-Pol-Ka

Dual-polarization and dual-wavelength S-band Doppler radar

Pictures courtesy NCAR

Ka-band radar

Objectives

• Improvement of basic understanding of the initiation and evolution of convection over moderate-mountain terrain.

T. Weckwerth, J. Wilson, S. Ellis (NCAR), M. Hagen (DLR)

• Improvement of very short period forecasts of convective precipitation processes.

J. Wilson (NCAR), W. Deierling (U. Alabama), A. Blyth (U. Leeds)

Objectives (cont.)

• Improvement of microphysical parametrization schemes in numerical models.

G. Zhang (U. Oklahoma), E. Brandes (NCAR)

• Improvement of radar data assimilation in numerical models.

G. Zhang (U.Oklahoma), J. Sun (NCAR), V. Wulfmeyer (U. Hohenheim)

Potential locations for

S-Pol-Ka

Site survey on 27 November 2005

J. Wilson (NCAR), M. Hagen (DLR)

DOWs

DOWs (Doppler on wheels) are X-band (3.2 cm) radars

Resolution along the beam direction: 25-50 m

Pictures courtesy CSWR

Objectives• How does the initiation of convection over the COPS region

depend on:

• the convergence and updrafts created by forced lifting on the windward side and thermally-forced anabatic flow,

• the wind shear profile normal to the ridges,

• variations in the depth of the convective boundary layer (CBL) and in convective inhibition (CIN) and convective available potential energy (CAPE) values across the mountain ridges,

• the presence of gravity waves impinging on the ridges, and

• the degree of dry air entrainment into developing cumuli?

Objectives (cont.)

• How does the enhancement of precipitation over the COPS region depend on:

• the wind flow direction relative to the ridge lines,

• static stability of the air being lifted and

• existing convergence features?

• How does boundary-layer convection interact with the topographically forced vertical velocity pattern?Are there particular conditions under which their superposition results in a greater likelihood of convection initiation?

Objectives (cont.)

• When mesoscale boundaries occur on the valley floor, how do they interact with the terrain as they propagate toward the mountains? If mesoscale vortices exist along the mesoscale boundaries, how does their structure and their influence on the vertical motion pattern change as they encounter terrain?

• How does the terrain influence the propagation and evolution of a convective system as it passes over moderately high terrain?

Y. Richardson (PSU), P. Markowski (PSU), J. Wurman (CSWR), T. Weckwerth, J. Wilson (NCAR)

Potential locations for

DOWs

Deployment strategy:

Several sites will be identified prior to the experiment and then selected daily depending on the expected flow conditions and missions.

Current funding status

Six weeks deployment of S-Pol-Ka ~ $ 618,000

100,000 Euro awarded by the DFG (for S-Pol-Ka or Dows)

125,000 GBP requested (for S-Pol-Ka) from the National Environment Research Council

Decision (for S-Pol-Ka and DOWs) from NSF expected in early June 2006

Site survey planned this summer