A Survey of Wyoming King Air and Cloud Radar Observations in the Cumulus Photogrammetric In-Situ and Doppler Observations (CuPIDO) experiment

J. Cory Demko (coryuw@uwyo.edu) Rick Damiani (rickdami@uwyo.edu) Bart Geerts (geerts@uwyo.edu) Joseph Zehnder (zehnder@asu.edu)

Department of Atmospheric Science, University of Wyoming Global Institute of Sustainability, Arizona State UniversityCumulus convection is of fundamental importance as it

serves as the primary mechanism for the vertical transfer of heat, moisture and momentum. Details of the evolution of cumulus convection at multiple scales, particularly the transition from shallow to deep convection, are important, since these processes must be parameterized in numerical weather prediction and general circulation models. CuPIDO examines fundamental cumulus dynamics and the two-way interaction between cumuli and the environment. The detrainment of momentum, heat and moisture by isolated cumuli is directly relevant to cumulus parameterization in NWP models An isolated mountain serves as a natural laboratory for the study of cumulus evolution, allowing continuous measurements by ground-based instruments, cameras, radiosondes, and aircraft. CuPIDO also aims to study how surface fluxes around an isolated mountain drives anabatic flow, moisture and heat convergence, and the initiation of shallow, mediocre, and deep convection.

Rationale

Scientific Objectives Characterize the onset and transition from shallow to deep convection using surface and upper air measurements, various ground-based profiling systems, in-situ and Doppler aircraft observations and stereo

digital photogrammetric techniques.

CuPIDO will advance scientific knowledge on several fronts:

fundamental cumulus dynamics orographic forcing of cumulus clouds cumulus-environment interaction

Who/What Was Involved? University of Wyoming

King AirWyoming Cloud Radar

Arizona State UniversityDigital Visible Spectrum

Cameras(2 stereopairs)

NCAR/EOL10 ISFF/PAM Stations2 M-GAUS mobile radiosondes

University of Arizona: WRF modeling Support

GPS water vapor

Site Location

 

Santa Catalina Mountains, north of Tucson, AZ. This range has a maximum elevation of about 2800 m (9000 feet) and referred to as a “sky island” .

16 flights were conducted between 18 July and 17 August 2006.

Orographic forcing of boundary layer flow: mass and moisture convergence

ISFF site

Camera site

Flight summaryNumber of flight hours: 60Number of flights sampling transition from cloud-free to Cu congestus: ~8Number of flights sampling transition to deep convection: ~7Number of flight loops around the mountain, in the convective BL:

25 July 2006 case illustrating orographic boundary layer forcing over the Santa Catalinas. Panels 1 – 3 illustrates circumnavigation loops at 1,000ft agl, 7,000ft msl, and 10,000ft msl conducted 1600 – 1647 UTC. Tracks show equivalent potential temperature and wind barbs are colored via mixing ratio. Panels 1 and 2 view the mountain top-down whereas panel 3 shows the southern periphery. Panel 4 illustrates an aircraft sounding from 1946 – 1953 UTC (23,000ft msl – 1,000ft agl). Track show equivalent potential temperature and wind barbs colored via potential temperature. Graphics produced using IDV.

Weak low - level upslope flow exists with very little if any wind shear. A relatively moist and cool boundary layer exists during the morning hours (MST) due to a Gulf of Mexico surge which arrived several hours prior. The

boundary layer contained more moisture than any other day up to this point. Rather high CAPE, but also significant CIN existed during this IOP.

Equivalent Potential Temperature (°K)

Mixing Ratio (g/kg)5 15

1

Equivalent Potential Temperature (°K)

Mixing Ratio (g/kg)5 15

N↑3

Potential Temperature (°K)

Mixing Ratio (g/kg)5 15

2

Eq

uiv

ale

nt

Pote

nti

al

Tem

pera

ture

(°K

)

Pote

ntia

l Tem

pera

ture

(°K)

330

3454

Successive shallow Cu developed between 1740 – 1840 UTC (~800m deep) evolving rapidly into congestus by 1935 UTC

Cumulus Dynamics using the Wyoming Cloud Radar (WCR)

18 July 2006 16:44:30 – 16:46:30 UTC (left) and 16:48:15 – 16:50:15 UTC (right) The figures show plumes detaching from the ground and connecting to clouds above.

18 July 2006 vertical plane dual Doppler image which shows a section of a turret tilting against the main wind direction. It is forming to the north of Mt. Lemmon.

18:03:30 – 18:04:20 UTC