Notice

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

• Be at the ABLE office at 2330 Ohio St, Augusta, KS.
• Have one PC to display conventional weather data and access CASES-97 surface, sounding and profile data for operational purposes.
• Have a speakerphone for conference calls with the Aircraft Operations Center and Radar Operations Center. It should be able to operate while at least one computer is on line.
• Have a fax for sending/receiving flight plans and systems status.
• Have communications to aircraft via VHF radio.
• Have space for 5-6 people on a short-term basis, and for 2-3 on a longer-term basis.

 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:

• Two telephone lines, one dedicated for computer communication and one for communication with the CASES Coordination Center.
• Fax machine.
• Overhead projector and screen for discussion of flight plans
• Speaker phone for conference calls

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

• Monitor surface-flux and meteorological data quality for the ASTER and PAM sites.
• Monitor special instrumentation, including ozone flux, soil moisture, cloud base (ceiliometer) and cloud cover (all-sky camera).
• Provide space for 1-2 PIs to do early-stage analyses of flux and radiosonde data.

 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

• Perform radar scans to monitor precipitation.
• Perform fair-weather scans in support of the CASES-I IOPs.
• Perform scans in support of Tammy Weckwerth’s project.

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)

• Present conditions at surface and 850 mb.
• Forecast maps (surface and 500 mb (12, 24, 36 hr)).
• Satellite image.
• Radar composite.

• Airframe and crew readiness.
• Flight-hour summary.
• Meeting science Objectives.
• Intercomparisons.
• Instrument status.

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

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

Web: www.mesoscale.iastate.edu

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

• Profiler/Sodar/RASS On-line at Augusta office
• PAM/ASTER ASTER base. (316)-986-5474
• CLASS (ATD representative) (303)-263-7556
• Aircraft Ponca City Pump Room (405)-762-2580

Greenwood Aviation (405)-767-0422

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

• Radar S-POL (radar representative) (316) 794 2804.
• NOAA surface flux site Ponca City (405) 762-2580
• Qualls site Julie Lundquist ABLE office or aircraft office

• Plans for IOPs
  • 48-hour outlook for precipitation
  • Wind direction
• Special Weather Concerns
  • Heavy rain
  • Flooding
  • Thunderstorms or Severe Weather
• Check to make sure noon sounding received by NWS

• Soil moisture (ASTER Web page)
• Bowen ratio map (Derive from ASTER Web page)

• System status chart
• Requested weather information

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

• System/intercomparison status and operations concerns (~5 min),
• Update on observations completed and fulfillment of scientific objectives (~5 min)
• The weather forecast and special weather concerns (Section 2.2.2, Section 3.5, ~10 min)
• Discussion (~15 min)
• The decision for commencing a 24-hour IOP (~5 min).
• Whether to keep the Krypton sensors bagged

• Beginning and end time of the 24-hour sounding IOP. Tentative beginning times are 1900 or 0530 CDT (Section 2.3.2). Note that the last sounding will be launched 1.5 h before the end of the IOP.
• Flight plans and launch time. Although details may vary, each flight plan must provide (See Chapter 5):
  • Horizontal divergences of mass, heat, moisture, and momentum
  • Vertical flux divergence
  • Data near at least 2 of the three profilers for comparison
  • Low-level flights past the three chemistry surface flux stations and as many of the other flux stations as practicable

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

• Message for sonde operators (Augusta). This will include:
  • Launch times (IOP or not)
  • Launch locations (2 of 3 sites for non-IOP days)
  • Whether sonde release time will be changed by threat of severe weather and time to check message machine for change.
• Augusta faxes sonde schedule to FAA ((316)-942-2101).
• Augusta notifies Argonne to insure Profilers sample full spectral data.
• Augusta notifies radar of IOP plans.
• Augusta notifies Iowa State.
• If an IOP is declared, Ponca begins to design flight plan for IOP.

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:

• Ponca faxes flight plan to Augusta (Fax: (316) 775-1291)

2.2.2 Special Weather Concerns

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

• Since the humidity devices on the surface stations are not rain-proof, a heavy-rain forecast sets in motion a protocol for protecting them. ATD Surface Operations Director keeps close track on the weather. If heavy rain is expected, s/he may have technicians/volunteers temporarily cover the fast humidity sensors at the 8 PAM/ASTER locations. .
• If there is a threat of thunderstorms or severe weather at radiosonde launch time, the soundings could be moved up or cancelled if this action enables sampling before the storm begins.
• In the unlikely event of a threat of flooding at the two river basin sites, a decision to protect or pull out the stations out may be necessary. The ATD representative has the final say on this decision.

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.

• Evaporation and sensible heat flux (i.e., Bowen ratios) from surface stations (ATD/NCAR representative).
• Previous days' rainfall from S-POL or WSR-88D (CASES-2 rep).

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.

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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