Gravity Waves – #1 The NSF/NCAR G-V Research Aircraft: A New Observing Platform for Environmental Research

Gravity Waves – #2 Other Research Aircraft DC-8 (with MTP) ER2, WB57 HALO (2009?) UK BAe-146 Smaller jets (Learjets, Falcon, etc) Commercial aircraft (esp. in special programs) Turboprop aircraft with wind-sensing (but altitude limitation): –NCAR C-130, P3s, etc. –King Air, Merlin, etc. Many more... but need a quality wind-sensing system

Gravity Waves – #3 G-V Characteristics Certified flight to 51,000 ft; climb to 41,000 ft fully loaded Max. range near 6000 n mi (>10,000 km) 12-person crew; satellite comm. system Wind-sensing: –radome-port system with dual INS/GPS and differential GPS –to be added: all-weather gust system, laser velocimeter, higher-quality INS/GPS

Gravity Waves – #4 Observing Gravity Waves Using Research Aircraft In Situ Measurements: –Wind: horizontal wind vertical wind turbulence characterization –Pressure (including high-resolution for perturbations) –Temperature and air density –Fluxes –Tracers (q, ozone, CO, aerosol conc., etc)

Gravity Waves – #5 Observing Gravity Waves Using Research Aircraft Remote Measurements: –Microwave Temperature Profiler (MTP)-2007 –Aerosol-Backscatter Lidar (HSRL)-2008 –GPS full-spectrum receiver-2008 –Future: Cloud Radar-2009 [Remote sensing of wind] [DIAL lidar(s)]

Gravity Waves – #6 Anticipated Accuracies: Horizontal wind: 0.5 m/s Vertical wind: <0.5 m/s Temperature: 0.3C Pressure: 0.3 mb? MTP: 1-2K, 100 m vertical (for all, resolution is much better so changes of perhaps 10% of these values can be measured reliably)

Gravity Waves – #7 What Capabilities Are New? Altitude and range (and plans for routine operation at UT/LS altitudes) High-quality wind system (with GPS corrections) and flux-measuring system Temperature profiling (soon) Pressure-sensing system capable of measuring pressure fluctuations with high resolution (via differential GPS and special attention to calibration of p measurements)

Gravity Waves – #8 airflow 375K 325K MTP measurements from DC-8 in SOLVE (from MJ Mahoney) p. altitude [km] 10 15

Gravity Waves – #9 GPS Full-Spectrum Receiver Enables the aircraft to perform like a “LEO” satellite: –occultation soundings at locations selected for coverage –ability to measure path-integral time delay in directions of a set of satellites, from above most water vapor –potential uses in conjunction with the MTP

Gravity Waves – #10 GPS

Gravity Waves – #11 Tracers: In addition to the basic parameters of the wave, it is possible to measure many tracers that are steady on the time scale of the wave: –water vapor –ozone –CO –particle concentration –etc.

Gravity Waves – #12 Pressure Measurements Aircraft all measure pressure and fly by reference to a constant pressure Normally, measured pressure fluctuations can't be distinguished from altitude changes GPS systems now provide a high-resolution reference altitude, valid (with diff. GPS) to ca. 10 cm. Opportunity to measure pressure fields with high spatial resolution (from D-value measurements)

Gravity Waves – #13 Measurement Opportunity In a gravity wave, can measure: –fluctuations u',v',w',T',p' (and hence density') –T profiler will provide N and H (or sounding) linear theory constraints these amplitudes, dependent on: k,l,m,N,H,f With all measured except m=vertical wavenumber, have highly constrained solution that provides m, vertical propagation, etc.

Gravity Waves – #14 Example (over Utah)

Gravity Waves – #15 Another Example

Gravity Waves – #16 Polarization Relations Expect vertical and horizontal amplitudes to be similar, and (for typical conditions seen in TREX) p fluctuations to be around 0.5 mb. The corresponding D-value changes are around 20 m, and so are measurable with the combined GPS/pressure system. (approx.)

Gravity Waves – #17 Another Example

Gravity Waves – #18 Variance Spectrum, w

Gravity Waves – #19 Variance Spectrum, w

Gravity Waves – #20 Variance Spectrum, u

Gravity Waves – #21 Observing Opportunities Long ferry legs at UT/LS altitudes provide opportunities for assembling climatology. (Example: TREX flown from Colorado, ferry legs to California) Aircraft showed good flight characteristics in turbulence (although experience limited) Above-cloud observations possible (and some will be accumulated routinely). Opportunity to characterize turbulence