Flight Plans for VOCALS 1. Cross Section Mission robwood/VOCALS/info/VOCALS... Flight Plans for...

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Transcript of Flight Plans for VOCALS 1. Cross Section Mission robwood/VOCALS/info/VOCALS... Flight Plans for...

  • Flight Plans for VOCALS

    1. Cross Section Mission

    Table 1 and Figure 1 shows the key parameters and C-130 flight plan agreed upon by the C-130 PIs at the

    VOCALS meetings in June 2007 and March 2008. Table 1 shows a brief summary of the critical aspects

    of the Cross-Section flights. Table 2 shows a leg-by-leg summary of the outbound portion of the Cross-

    Section flight for a typical 9 hour flight out to approximately 85°W. Take off will be within 1 hour of 3am

    to minimize diurnal aliasing when combining data from these missions. Level (fixed altitude) legs of 10

    minute duration will be conducted at three different nominal altitudes:

    1) Subcloud layer (layer below almost all cloud, typically 150 m altitude, the minimum permitted for night flying);

    2) Cloud layer (layer close to center of stratocumulus cloud deck, which will range from 800-1300 m depending upon synoptic conditions, and will usually increase gradually westwards); the cloud layer

    will periodically be of a broken nature and the expectation is that this run may therefore pass into clear

    regions between clouds; small height adjustment can be made close to the start of the run to ensure the

    optimal cloud sampling.

    3) Free-tropospheric layer (layer approximately 500-1000 m above cloud top in the free-troposphere). This layer will be cloud free.

    In between these level legs, the C-130 will conduct profiles between the layers, and also up to

    approximately 4 km (exact height depending upon aerosol structure) as shown in Figure 1. The nominal

    ascent/descent rate will be 1000 ft min -1

    (300 m min -1

    ).

    At some point during the Cross-Section missions the C-130 will rendezvous with the NOAA R/V Ronald

    H Brown (RHB) and a collaborative flight maneuver described in Figure 2 will be conducted on the

    return portion rendezvous location. This involves:

    1) Low level run (150 m) to intercept the RHB 2) Turn to upwind direction (usually ESE, or SE) for subcloud run for 10 minutes at 150 m altitude 3) 180 degree turn and profile up to cloud level to conduct 10 minute return leg toward RHB at nominal

    cloud altitude

    4) Turn back onto Cross-Section Mission and resume cloud leg.

    Table 1: Key parameters for the C-130 Cross-Section Missions

    Flight duration Typically 9 hours

    Take off time Within 1 hour of 03:00 local

    Landing time Approximately noon local

    Key waymarkers From Arica (18° 29' S, 70° 20' W) to waypoint (20°S,

    72°W) then along 20°S to final location (82-85°W, 20°S)

    Notes

    Rendezvous for 20-30 minute cosampling with Ronald H

    Brown which will be located at different locations along

    20°S.

    Profile ascent/descent rate 1000 ft min -1

    (300 m min -1

    )

    Level leg duration 10 minutes (all runs)

  • Figure 1: Schematic flightplan for Cross-Section missions.

    Figure 2: Schematic of Cosampling with Ronald H Brown during rendezvous on the C-130 Cross-Section Missions.

  • Table 2: Leg-by-leg summary of the outbound portion of the Cross-Section flight for a typical 9 hour flight out to

    approximately 85°W. Assumed parameters are: Ascent/Descent rate 300 m/min, cloud leg height = 1100 m,

    subcloud leg height = 150 m, free-tropospheric (FT) leg height= 2000 m; maximim height for profiles, i.e. level H =

    4000 m, aircraft ground speed = 100 m/s. The inbound portion of the flight will be a mirror image of the outbound

    portion.

    Leg type Leg time

    [min]

    Leg dist

    [km] Altitude change [m]

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-H 9.67 58 2900

    Profile H-S 13.00 78 -3900

    Subcloud 10.00 60 0

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-F 3.00 18 900

    FT 10.00 60 0

    Profile F-S 6.33 38 -1900

    Subcloud 10.00 60 0

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-F 3.00 18 900

    FT 10.00 60 0

    Profile F-S 6.33 38 -1900

    Subcloud 10.00 60 0

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-H 9.67 58 2900

    Profile H-S 13.00 78 -3900

    Subcloud 10.00 60 0

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-F 3.00 18 900

    FT 10.00 60 0

    Profile F-S 6.33 38 -1900

    Subcloud 10.00 60 0

    Profile S-C 3.33 20 1000

    Cloud 10.00 60 0

    Profile C-F 3.00 18 900

    FT 10.00 60 0

    Profile F-S 6.33 38 -1900

    Subcloud 10.00 60 0

    Total to halfway 4.38 1576 0

    Deg W traveled 15.08

  • 2. POC-Drift Mission

    Table 3 and Figure 3 shows the key parameters and C-130 flight plan agreed upon by the C-130 PIs at the

    VOCALS meetings in June 2007 and March 2008. Table 3 shows a brief summary of the critical aspects

    of the Cross-Section flights. Table 4 shows a leg-by-leg summary of the POC-Drift flight for a typical 9

    hour flight assuming that the POC boundary (target location) is situated at 21°S, 78°W. Stacks (probably

    two at most) of level (fixed altitude) legs of 25-30 minute duration will be conducted at four different

    nominal altitudes. To facilitate communication we will term these legs the subcloud, cloud-base, cloud,

    and free-tropospheric legs, but it must be appreciated that, especially within the POC, the clouds are

    particularly heterogeneous, so that the boundary layer will not be separable into clearly defined cloud

    and subcloud layers. Instrument sampling strategy, particularly for those measurements which require

    considerable integrating time, must take this into account.

    1) Subcloud layer (layer below almost all cloud, typically 150 m altitude, the minimum permitted for night flying);

    2) Cloud-base layer. This is a layer approximately 100 m above the lifting condensation level (LCL) of the surface air, which will contain a mixture of clouds and clear air. This is the critical level for

    midlevel mesoscale inflow into the precipitating centers within the POC.

    3) Cloud layer. This is a layer close to center of stratocumulus cloud deck, which will range from 800- 1300 m depending upon synoptic conditions); the cloud layer will periodically be of a broken nature

    especially on the POC side of the POC boundary and the expectation is that this run may therefore

    pass into clear regions between clouds; small height adjustment can be made close to the start of the

    run to ensure the optimal cloud sampling.

    4) Free-tropospheric layer (layer approximately 500-1000 m above cloud top in the free-troposphere). This layer will be cloud free.

    In between these level legs, the C-130 will conduct spiral or 180 degree turn profiles between the layers.

    The nominal ascent/descent rate will be 1000 ft min -1

    (300 m min -1

    ). At least two profiles will be

    conducted in each of the two regions (POC and non-POC).

    Table 3: Key parameters for the C-130 POC-Drift Missions

    Flight duration Typically 9 hours

    Take off time Either 03:00-4:00 local or 09:00-10:00 local depending

    upon whether C-130 is in day or night mode

    Landing time Either 12:00-13:00 local or 06:00-07:00 local depending

    upon whether C-130 is in day or night mode

    Key waymarkers

    From Arica (18° 29' S, 70° 20' W) to predetermined POC

    boundary location. Sampling within 150 km of this

    boundary and then returning to Arica

    Notes May occur in region with RHB, either upstream or

    downstream

    Profile ascent/descent rate 1000 ft min -1

    (300 m min -1

    )

    Level leg duration 20-30 minutes (all runs)

  • Figure 3: Schematic flight plan for the POC-Drift missions.

  • Table 2: Leg-by-leg summary of the outbound portion of the POC-Drift flight for a typical 9 hour flight. Transit time

    will vary depending upon POC location. Assumed parameters are: Ascent/Descent rate 300 m/min, cloud leg height

    = 1100 m, cloudbase leg height 750 m, subcloud leg height = 150 m, free-tropospheric (FT) leg height= 2000 m;

    maximim height for profiles, i.e. level H = 4000 m, aircraft ground speed = 100 m/s.

    Leg type Leg time

    [min]

    Leg dist

    [km]

    Leg elev

    change [m]

    Transit from Arica

    STACK 1:

    Subcloud 30.00 180 0

    Profile S-F in POC 6.50 39 1850

    Profile turn F-Cb 3.00 18 -1250

    Cloudbase 30.00 180 0

    Profile turn Cb-C 3.00 18 350

    Cloud 30.00 180 0

    Profile turn C-F 3.00 18 900

    FT 30.00 180 0

    Profile F-S out of POC 6.50 39 -1850

    STACK 2:

    Subcloud 30.00 180 1850

    Profile S-F in POC 6.50 39 -1250

    Profile turn F-Cb 3.00 18 0

    Cloudbase 30.00 180 0

    Profile turn Cb-C 3.00 18 350

    Cloud 30.00 180 0

    Profile turn C-F 3.00 18 900

    FT 30.00 180 0

    Profile F-S out of POC 6.50 39 -1850

    Repeat if time permits

    Transit to Arica

    Total on task 4.73 1704 0