2. Operations Coordination and Oversight

Daily meetings will be necessary to determine when daily observations escalate into an Intensive Observing Period (IOP). There will be 5 IOPs. During an IOP, radiosondes will be launched at 90-minute intervals and aircraft operations will complement the data.

Each IOP is 24 hours long; during this time there must be no rainfall. It is desirable that the IOP's sample days with different surface characteristics, ranging from wet days (with very moist ground with large evapotranspiration and evaporation) to dry days (with dry ground and small evaporation and patchy evapotranspiration, Section 2.3.1). Starting times for the IOP will be staggered to insure capture of all phases of the diurnal cycle (Section 2.3.2).

ES-1, Bob Grossman, Bob McMillen, and Peggy LeMone, with consultation with representatives from the S-POL group (CASES-2). The facilities representatives (NCAR/ATD for flux and radiosonde stations; University of Wyoming for King Air, NOAA/AOC for Twin Otter), will be contacted to insure that all measurement systems are ready to operate. Cooperating investigators (Cuenca for CASES-1d soil moisture experiment, Arritt for JETEX) will be informed of our status and IOP decision.

2.1. Operations Centers

There will be four major centers of operation.

2.1.1. The CASES-97 Coordination Center will be the focal point for IOP decisions and IOP coordination. The CASES Operations Director (LeMone) will work there. It will

 2.1.2 The Aircraft Operations Center will be located in the Pump Room of the Marlin Manor Hotel, Ponca City, Oklahoma. Aircraft will be based at Greenwood Aviation, Ponca City Airport. The Pump Room can seat about 40 persons. NOAA will have their data reduction operations in the Pump Room and can make one of two computers available for communications as necessary for primary operations. The Aircraft Operations Director (Grossman) will work at the Pump Room and perform aircraft data analysis there with the NCAR computer (citron). NSF/Wyoming data reduction operations will be at Greenwood Aviation.

 The aircraft operations center in the Pump Room will have the following support:

2.1.3 The Surface-Flux Operations Center or ASTER Base will be located at the J.C. Braungardt farm east of Rock, KS. The NCAR/ATD Surface-flux Coordinator (Steve Oncley or substitute) will be located there. The Surface-Flux Operations Center will

 2.1.4 The Radar Operations Center will be 6 mi WNW of Wichita Airport (37 deg 40'30'' N, 97 deg 33'02''W). It will

2.1.5 The JETEX program will be run remotely, from the University of Iowa.

2.1.6 The soil-moisture project will be run remotely, from Oregon State University.

2.2. Daily Operations

2.2.1 Timeline

The timing of the following daily tasks is dictated by the need to have 12-hour notice for radiosonde launches. Weather will also be monitored continuously from watching the Weather Channel.

CASES-97 will use Local daylight time for communications and display purposes.

Time will be set using GPS.

Augusta = Cases Coordination Office; Ponca = Aircraft Coordinations Office.

0830 CDT: Augusta and Ponca reps watch the Weather Channel

Prepare for daily conference call (start late morning)

1. Augusta, Ponca download national/regional weather information from Internet (this frees up fax for communication in the afternoon)

2. Ponca obtain aircraft status

3. Augusta Check with Iowa State JETEX plans and forecast (they will normally call between 1300 and 1330).

Tel: (515)-294-9870 (w)


4. Augusta gets CASES/ABLE Systems Status and discusses plans

Greenwood Aviation (405)-767-0422

At this time also check to see if it necessary to fax weather data to Ponca.

5. Augusta joins 1400 briefing from Weather Service (Tels: 945-3687; 945-3842)

6. Augusta obtains CASES surface/BL conditions

7. Augusta faxes materials to Ponca City (FAX: (405) 763-5813)

8. Augusta calls Ponca City (Phone: (405) 763-5809) to confer with Grossman and Wellman (at 1430-1530 CDT or a preset time)


9. When it is decided to have an IOP, the next decisions are:

 10. By 1600 CDT (or at the close of the conference call):

Augusta writes up summary of discussion and plans and emails CASES97 community describing plans (mailing list under Appendix 7A: Addresses); summary will be updated on the CASES Web page periodically but not daily

11. Befone morning:

Aircraft time-line in Section 5.6

2.2.2 Special Weather Concerns

When heavy rains, severe weather, or flooding threatens, special actions may be necessary.

2.3. Definition of an IOP

2.3.1. Proper Weather Conditions

For an IOP, the weather forecast must be for no rain for the period from 12-15 hours to 48 hours from conference call time. This requirement allows 12 hours for notification plus 24 hours for rain-free operations. Aircraft should be prepared for operations, and an acceptable mix of surface stations should be running.

If a rainless period is forecast, the next criterion is whether surface conditions meet the requirements of the scientific objectives. IOPs will be sought to capture a range of Bowen ratios (ratio of surface sensible to latent heat flux), which will be driven by surface wetness and plant transpiration. Ideally, the range of conditions would be from a totally wet surface, to days of intermediate degrees of dryness with patchy surface moisture, to a day with dry soil and low evapotranspiration.

The following data will be used to decide whether surface conditions are appropriate.

2.3.2 IOP Timing

0600 CDT (sunrise) and 1800 CDT (sunset) have tentatively been set as beginning times for IOPs. These times ensure capture of most of the interesting features of the diurnal cycle, (Fig. 2.1), and ensure correspondence with JETEX and synoptic launches. Three IOPs should commence at 0600 CDT, and two of the IOPs at 1800 CDT.

Nocturnal BL
/           \
Morning Transition
/           \
Convective BL
/        \
Evening Transition
/           \
Nocturnal BL
/           \












Aircraft Operations










Fig. 2.1. Timing of phases in the diurnal evolution of the ABL, namely Morning Transition which includes the change from stable to convective conditions, and rapid growth; Daytime Convective Boundary Layer fairly steady-state conditions; Evening Transition from convective to near-neutral to stable (Also called ABL collapse); Night-time evolution of the BL including development of the low-level jet (several hours after sunset to just after sunrise). Aircraft operations are limited to daylight hours.

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Last Modified: 20 Aug 1997