• Sample clouds, aerosols, water vapor, radiative fluxes, and tracers of convection in hours-days old outflow from deep convection. The WB-57 will be the primary aircraft for this sampling, but if clouds and convective outflow extend low enough then the Citation will be useful as well. The ER-2 can be used for cloud remote sensing and radiation measurements.

• Measure the radiative flux divergence in the tropopause region both in clear sky conditions, and with optically thin clouds.

• Sample the water vapor, tracers, aerosols, and clouds in the tropopause region and lowermost stratosphere.

• If possible, coordinate these flights with Aqua or Terra satellite overpasses.

Pickering and Selkirk/Pfister will be providing tracer forecasts and predictions of convectively influenced regions. Presumably, on days when no suitable Cbs are forecast in the south Florida region we may be able to identify regions where we can sample aged convective outflow (hours to days old). These regions may well include detached cirrus layers including optically thin cirrus in the tropopause layer. Ideally, we would sample these regions over one of the ground sites such that we can use the lidars to identify optically thin cloud layers. If possible, we should also try to time these flights to include coordination with Aqua or Terra overpasses. We may want to head south avoiding Cuba) to reach air more typical of the deep tropics. By sampling these airmasses/clouds and measuring tracers of convection, we should be able to address science questions involving the evolution of convective outflow in the upper troposphere, the influence convection on upper tropospheric water vapor, and the influence of convection on water vapor concentrations in the lowermost stratosphere. In addition, we can use the WB-57 and ER-2 to measure the radiative flux divergence in the tropopause layer by flying coordinated legs near the tropopause.

WB57: Launch and fly to the target location. Fly stairstep pattern perpendicular to the wind with 10-15 minute legs separated by 500 feet. The back-seater should have a display of the CO concentration to locate where the maximum convective outflow is. Adjust the leg endpoints such that the legs are centered on the maximum outflow location. Start at the forecast altitude of maximum convective outflow and stairstep up to the WB-57 ceiling, then step down to 45 Kft. After the stairstep pattern is completed, fly a 15 minute leg along the outflow at the altitude of maximum CO concentration. If narrow cirrus layers are present, then additional legs may be necessary to sample the clouds. If time permits, repeat this flight pattern further upstream or downstream in the convective outflow.

If the WB-57 will be used to for the tropopause layer radiative budget experiment, then follow the flight plan described for the ER-2 below.

ER-2: Launch and fly to the target location. Fly 15 minute leg downwind at 150 mbar. Then make a 90-270 turn and fly back along the same path. The duration of this leg will be shorter (depending on the wind speed). This return leg will determine the variability of the radiative fluxes (due to both instrument precision and temporal variability). Next, ascend to 80 mbar and fly a 15 minute downwind leg. Then make a 90-270 and fly back along the path at 80 mbar. Repeat these back-and-forth legs at 80 and 150 mbar as long as possible. We may want to shift the location of the pattern based on ground-based lidar or WB-57 measurements. If we are over water, launch one dropsonde when arriving at the target and one just before departure.

CIT: If cirrus layers in the target location extend below 44 Kft, then the Citation should be used to sample them. Launch well after the WB-57, fly to the target location and fly a stairstep pattern underneath the WB-57. The flight leg altitudes should extend from the base of the cirrus up to the Citation ceiling.