Notes on Socorro Meeting, January 2001 - EPIC2001

Dave Raymond

Here are some notes on the Socorro meeting of EPIC2001 principal investigators.

  1. Location and timing of program - Aircraft base: Huatulco, México, with Acapulco as a fallback. Aerosonde base: San Cristóbal, Galápagos, Ecuador. 1 Sept - 15 Oct 2001. (See issues below which determine this.)
  2. What is new on the scientific front?

    1. Recent work by George Kiladis shows that Kelvin waves arriving from the west potentially have an effect on east Pacific convection as well as the MJO (Maloney and Hartmann) and easterly waves. We need to take this possibility into account.
    2. Esbensen indicates that the flow of air northward over the SST front near 3 N may be more complex than previously expected. He would like some multi-level flights over this region to try to measure structure and fluxes there.
    3. Mike Gregg indicated that oceanic mixing in the Andaman Sea is quite episodic, and depends on the production of unstable layers by inertial oscillations. The same processes may be a work in the east Pacific.
    4. Bretherton lamented the lack of aerosol instrumentation on the Ron Brown, as aerosols are instrumental in the cloud physics of the marine layer. Darrel Baumgardner may be able to put some instrumentation on the ship.
    5. Chidong Zhang pointed out that the easterly wave variance in OLR actually occurs to the north of the nominal position of the ITCZ. Zehnder and Molinari have shown similar results.

  3. Facilities issues

    1. JOSS will have a Seaspace ground station at the operations center in México. This provides a wide variety of satellite products, with data being downloaded directly from the satellites. The SEAWIFS software needs to be upgraded on this system.
    2. John Bates indicated that easterly waves were quite visible in various forms of water vapor imagery, such as total column water from SSMI and TMI instruments. We need to develop a more detailed plan as to what to do with satellite imagery in the support of operational decisions.
    3. Meghan Cronin indicated that the 95 W TAO mooring line is subject to a lot of vandalism. Therefore it is imperative to make repairs to the moorings from the equator to 12 N just before the project. The current thinking is to try to get extra time on the Ron Brown to carry out this task before the beginning of the observational program.
    4. Esbensen stressed that communications between the Galápagos and the Mexican operations center is crucial in order to coordinate observations. The internet in the Galápagos is shaky, but email seems to work. A satellite phone is essential as a backup.
    5. We need to decide by roughly April 2001 whether the ships and aircraft operations will be centered at 10 N or 8 N. This decision will presumably be based on whether an el Niño is likely to develop during the observational period.
    6. Gus Emmanuel indicated that on the basis of two trips to the region that Huatulco has the facilities needed to execute the experiment. The hotels on Tangolunda Bay are the only ones with all the facilities we need, including space for an operations center and reliable internet connections. These are normally quite expensive, but the project as currently scheduled (1 Sept - 15 Oct 2001) will take place in the low season, and favorable room rates are coming out of the negociations. The airport is normally open from 6 AM to 7 PM, but exceptions can be made on 24 hour notice. Fuel is available. The main thing lacking is the availablility of work space at the airport. Al Schanot from NCAR/RAF will travel to Huatulco later this month to evaluate facilities.
    7. José Meitín (NOAA, JOSS) is working on a data management plan, to support both operations and later research.
    8. Gene Martin (JOSS) will be sending out a survey of the needs of research groups. This is important for planning, so please respond.
    9. Diane Lask (JOSS) will be handling shipping.
    10. The question of a second aircraft is still up in the air. Jay Fein indicated that it is highly unlikely that the Electra will be available to the project. The NRL P-3, which is supposed to carry the Eldora radar in the future, will not be available either. NOAA has received supplementary funds for P-3 operations, so an effort is underway to revive our P-3 request at NOAA. We should know the status of this request soon.

  4. Aircraft plans - We have been awarded 162 h of NCAR C-130 research time. Two plans are presented, with and without a NOAA P-3. The P-3 plan assumes that 144 h of research flight hours are available.

    1. C-130 by itself:

      1. 95 W traversals: 7 C-130 flights at 10 h each. Outbound to equator in the marine layer, dropping ocean probes and making flux measurements, inbound at high levels (6000-7000 m) dropping dropsondes at 1 degree intervals. Multi-level traverses will be made over SST front.
      2. ITCZ traversals: 5 C-130 flights at 9 h each. Cloud physics traversals from 8 N to 12 N on or near 95 W, altitudes of 300 m, 1000 m, 3000 m, 5000 m, dropsondes on 5000 m leg.
      3. ITCZ mesoscale patterns: 5 C-130 flights at 9 h each. C-130 flies at 3000 m in 4 degree square pattern centered on 95 W, 10 N, as specified by Shay et al., dropping dropsondes and ocean probes.

    2. C-130 plus a NOAA P-3:

      1. 95 W traversals: 9 C-130 flights at 10 h each. Outbound to equator in the marine layer, dropping ocean probes and making flux measurements, inbound at high levels (6000-7000 m) dropping dropsondes at 1 degree intervals. Multi-level traverses will be made over SST front.
      2. ITCZ traversals: 8 C-130 flights at 9 h each. Cloud physics traversals from 8 N to 12 N on or near 95 W, altitudes of 300 m, 1000 m, 3000 m, 5000 m, dropsondes on 5000 m leg.
      3. ITCZ mesoscale patterns: 16 P-3 flights at 9 h each, coinciding with C-130 flights. P-3 flies in 4 degree square pattern centered on 95 W, 10 N, as specified by Shay et al. For 6 flights the P-3 flies at 3000 m, dropping both dropsondes and ocean probes. For 10 flights the P-3 flies at 6000 m, dropping just dropsondes. In both cases continuous radar observations are made. The ocean probe measurements should be made when the ship Ron Brown is on station at 95 W, 10 N.

  5. Aerosonde plans - Two-plane "budget" flights will be made between 2S and 5N along or near 95W in conjunction with C-130 flights from Huatulco, the New Horizon equatorial transect, and the Ron Brown stratocumulus pilot cruise. Single-plane "survey" flights will be made along 95W between 5S and 5N when the C130 or ships are not available. Detailed plans are still being developed.
  6. Ship plans

    1. The Ron Brown will possibly first service the 95 W TAO moorings from 12 N to the equator. Roughly 20 days will then be spent in the ITCZ at 95 W, most likely at 10 N, though possibly at 8 N if an el Niño occurs. It will then proceed down the 95 W line and then steam to the IMET mooring at 85 W, 18 S.
    2. The New Horizon will work in conjunction with the Ron Brown in the ITCZ, making mesoscale patterns around the Brown. It will then steam down the 95 W line to the equator and back.

  7. Aircraft issues

    1. John Bates suggested that it would be valuable to coordinate flights with overpasses of the TRMM radar and the various microwave sounders. The radar presents much more challenging coordination issues due to its narrow swath. There was broad agreement that coordination with the microwave sounders would be quite valuable.
    2. If we get a NOAA P-3, it should be the one with the ocean probe data system on it. Both P-3s will be working on a USWRP project during the summer of 2001. However, their flights may well be finished by the time we need the P-3, since they plan to study a single hurricane intensively.
    3. Nick Shay has enough dropsondes to use them on the ITCZ traversals as well as on the 95 W and mesoscale patterns.
    4. We need to have intercomparisons between the C-130 and the P-3, between the aircraft and the ships, and between the aircraft and the buoys. We can arrange for C130 and P-3 flights past the ships on almost every flight. In addition, the aerosondes need to be intercompared with the Galapagos sounding, on every mission if possible, and with each other on two-plane missions. We should consider an intercomparison between a dropsonde and an Aerosonde.
    5. We need to resolve how to handle the diurnal cycle issue.
    6. Aircraft instruments needed beyond what we have already requested:

      1. Can we borrow a CAPS? This replaces a wide variety of particle instrumentation.
      2. WARDS (recording of the pilot's radar).
      3. High rate data (implies Lyman alpha instruments).
      4. Laser hygrometer may be able to replace the wetbulb instrument. Tests will be made on this instrument in two projects preceeding EPIC2001.
      5. Can we borrow an HVPS? This yields a larger sample volume for large precipitation particles.
      6. CVI? This will be on for DYCOMS and it measures total condensed water.
      7. Darrel Baumgardner and Graciela Raga will supply instruments to measure CCN, optical properties of aerosols, and the size distribution of small aerosols.

    7. Storage of dropsondes and ocean probes on the C-130 is an issue.
    8. The maximum people load on the C-130 is 19. This should not be an issue.
    9. The C-130 cannot start before 1 September. Later is possible.
    10. At night NCAR aircraft cannot descend closer than 500 ft to the surface (except of course for landing and takeoff!). This constrains boundary layer operations at night. The NOAA P-3s have a similar limitation.

  8. Ship issues - The main issue is one of scheduling. Four possible schedules are presented below. Two of them allow the servicing of the 95 W TAO array just before the start of the project. Due to vandalism, it is quite important that this be done.

    1. Plan 1: (Currently planned schedule.) New Horizon departs San Diego 18 August, Ron Brown departs San Diego 3 September. This allows only 15 d overlap in the ITCZ and doesn't allow the TAO array to be serviced.
    2. Plan 2: As in plan 1 except Ron Brown departs San Diego on 28 August. This gives 20 d overlap in the ITCZ but still doesn't allow the TAO array to be serviced.
    3. Plan 3: The Ron Brown departs about 6 days earlier than plan 2 (about 22 August) and uses the extra time to service the TAO array.
    4. Plan 4: Change New Horizon schedule so that it departs San Diego on 8 September. Ron Brown departs San Diego 3 September and services TAO array. ITCZ work starts 16 September.

  9. Satellite issues - John Bates will work on providing the following:

    1. Aerosol products
    2. Information on ITCZ diurnal cycle
    3. WEB/FTP products
    4. SST
    5. Surface wind stress
    6. Low cloud amount
    7. Hovmöllers and animations
    8. MJO and Kelvin wave phase
    9. Time series at flux moorings
    10. SEAWIFS reception

  10. Coordination issues - These all require reliable communications between ships, the operations center in México, and the Aerosonde operation in the Galápagos.

    1. The two aircraft should fly one or two intercomparsion flights.
    2. The C-130 should make a low pass by the Ron Brown each flight for flux intercomparison purposes.
    3. Cloud physics measurements on the C-130 should be coordinated with Ron Brown radar observations.
    4. The C-130 and the Ron Brown should meet in the SST front for a joint study of this region.
    5. An intercomparison should be made between a dropsonde and an Aerosonde.
    6. The Aerosondes will fly at the same time the C-130 flies. Coordination of flight patterns and timing must be done.
    7. Aircraft flights should be coordinated with SSMI or TMI microwave scanner overflights, and possibly with TRMM radar overpasses. (The latter will be difficult due to the radar's narrow swath, and may not be feasible.)

  11. Forecasting - We are primarily interested in the westward progression of easterly waves through the project area, and in the eastward progression of Kelvin waves and the MJO. John Molinari will provide input based on model analysis data, while John Bates will provide input from satellite observations. We expect some input to come also from George Kiladis regarding Kelvin waves and the MJO, based on work done by Matt Wheeler and Klaus Weickmann.

File translated from TEX by TTH, version 2.00.
On 3 May 2001, 14:35.