Kavaya-1 Coherent Doppler Lidar Roadmap to Both the NRC Decadal Survey “Science Demonstration” and “Operational” Missions Michael J. Kavaya Jirong Yu Upendra Singh NASA Langley Research Center Mulugeta Petros Science and Technology Corp. Working Group on Space-Based Lidar Winds Monterey, California USA 5 – 8 February 2008

Kavaya-2 Geometry 400 vs. 824 km 45 degree nadir angle Spherical earth 400 – 48.5 s/350 km 824 – 53.1 s/350 km

Kavaya-3 Geometry 400 vs. 824 km 45 degree nadir angle Flat Earth Spherical Earth CDWL Simulation Pulse Energy (i.e., all effects included) Ratio of Slant Ranges (eff) Ratio of Squares of Slant Ranges dB of Ratio of Squares of Slant Ranges

Kavaya-4 NASA/NOAA Wind Measurement Requirements Part 1 of 3 Science Demonstration Operational Vertical depth of regard (DOR)0-20 km Vertical resolution: Tropopause to top of DOR Top of BL to tropopause (~12 km) Surface to top of BL (~2 km) km Horizontal resolution A 350 km Minimum Number of horizontal A wind tracks B 24- Number of collocated LOS wind measurements for horizontal A wind calculation 2 = pair - Velocity error C Above BL In BL m/s Minimum wind measurement success rate D 50 % A Horizontal winds are not actually calculated; rather two LOS winds with appropriate angle spacing and collocation are measured for an “effective” horizontal wind measurement. The two LOS winds are reported to the user. B The 4 cross- track measurements do not have to occur at the same along-track coordinate; staggering is OK. C Error = 1  LOS wind random error, projected to a horizontal plane; from all lidar, geometry, pointing, atmosphere, signal processing, and sampling effects. The true wind is defined as the linear average, over a 100 x 100 km box centered on the LOS wind location, of the true 3-D wind projected onto the lidar beam direction provided with the data. D Scored per vertical layer per LOS measurement not counting thick clouds

Kavaya-5 Pulsed Doppler Wind Lidar Concept Science MissionOperational Mission NRC 2007 Earth Science Decadal Survey Recommended Demonstration “3-D Winds” Mission in 2016 NRC 2007 Earth Science Decadal Survey Recommended Operational “3-D Winds” Mission in 2022

Kavaya-6 NASA/NOAA 2008 Wind Measurement Requirements Science Demonstration Mission Operational Mission Current Horizontal Wind Vertical Profile Observations ~23 km Global averages If 2 measurements in a box, pick best one Emphasis on wind profiles vs. height Courtesy Dr. G. David Emmitt Note different color key

Kavaya-7 Equal Performance Parameter Linkages: Note: better vertical resolution is a smaller value of “Vert Res” If decrease (improve) Vert Res by a factor F, then increase E by a factor, or increase PRF by F, or increase D by If increase number of azimuth angles N AZ by a factor F, then increase PRF by F, or increase Vert Res by F, or increase E by, or increase D by If increase R by a factor F, then increase D by F, or increase E by F 2, or increase PRF or Vert Res by F 4 Connecting Lidar Parameters to Measurement Performance Coherent Detection Doppler Wind Lidar

Kavaya-8 Coherent Doppler Lidar Roadmap to Hybrid DWL Science and Operational Missions: Science Demonstration, 400 km GWOS Mission No. Sat. Lidars per Sat.** Aperture Pulse Energy PRF TX/RX Misalignment Angle, dB Loss Requirements: Science Demonstration z SAT = 400 km t RT = 3.9 ms (TX/RX misalignment = Gaussian RV, zero mean, std. dev. = X microradians Loss MIS = Y dB) m*250 mJ5 Hz 3.08  rad, 3 dB Least desirableMost desirable *assume no SNR loss due to scanner effective aperture **Does not include spare lasers for each lidar Point Design With Requirements Exceeded

Kavaya-9 Mission No. Sat. Lidars per Sat.** Aperture Pulse Energy PRF TX/RX Misalignment Angle Requirements: Operational z SAT = 400 km t RT = 3.9 ms m*500 mJ5 Hz 3.08  rad, 3 dB m*354 mJ10 Hz 3.08  rad, 3 dB m*250 mJ20 Hz 3.08  rad, 3 dB 111 m*496 mJ20 Hz 3.08  rad, 12 dB 111 m*63 mJ20 Hz 1.54  rad, 3 dB 111 m*125 mJ5 Hz 1.54  rad, 3 dB Coherent Doppler Lidar Roadmap to Hybrid DWL Science and Operational Missions: Operational, 400 km *assume no SNR loss due to scanner effective aperture **Does not include spare lasers for each lidar Least desirable Most desirable Note: 250 mJ x 2 = 500 mJ

Kavaya-10 Coherent Doppler Lidar Roadmap to Hybrid DWL Science and Operational Missions: Operational, 824 km Mission No. Sat. Lidars per Sat.** Aperture Pulse Energy PRF TX/RX Misalignment Angle Requirements: Operational z SAT = 824 km t RT = 8.4 ms m*2330 mJ5 Hz 3.08  rad, 3 dB m*1650 mJ10 Hz 3.08  rad, 3 dB m*1170 mJ20 Hz 3.08  rad, 3 dB m*2190 mJ5 Hz 3.08  rad, 4.3 dB m*2320 mJ5 Hz 3.08  rad, 5.9 dB 111 m*583 mJ5 Hz 1.54  rad, 3 dB 111 m*292 mJ20 Hz 1.54  rad, 3 dB m*2330 mJ0.625 Hz 3.08  rad, 3 dB m*825 mJ5 Hz 3.08  rad, 3 dB m*1000 mJ5 Hz 3.08  rad, 1.9 dB m*1970 mJ5 Hz 3.08  rad, 0.75 dB *assume no SNR loss due to scanner effective aperture **Does not include spare lasers for each lidar Different orbit period not included Least desirableMost desirable Note: 500 mJ x 4.67 = 2330 mJ

Kavaya-11 Status of LaRC 2-Micron Pulsed Laser Demonstrated Performance Pulse Energy*PRFComponentsCoolingPackaging 12/ mJ2 Hz Oscillator + 2 Amplifiers (both 2-pass) Laser Diodes Conductive; Laser Rod Liquid Optical Table 8/ mJ5 Hz Oscillator + 1 Amplifier (2-pass) All ConductiveCompact 11/ mJ10 Hz Oscillator + 1 Amplifier (2-pass) Laser Diodes Conductive; Laser Rod Liquid Compact, Engineered Space Science Demo Mission 250 mJ5 Hz Oscillator + 1 Amplifier All Conductive Compact, Engineered, Space Qualified Space Operational Mission 500, 1650, or 825 mJ 5 or 10 Hz TBDAll Conductive Compact, Engineered, Space Qualified * 1 pulsette per pulse

Kavaya-12 Brought to you by NASA, NOAA, IPO, and the Ad Council