Laser Radar (LIDAR) Applications to Weather and Climate Studies

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1 Laser Radar (LIDAR) Applications to Weather and Climate Studies Prof. Panuganti CS Devara Amity Centre for Ocean-Atmospheric Science and Technology (Amity COAST) Amity University Haryana, Panchgaon (Manesar) Gurgaon Other Contributors: Dedicated team at Indian Institute of Tropical Meteorology (IITM), Pune, India

2 OUTLINE Introduction Lidar Configurations Lidar Facilities Long-term Changes and Trends in Aerosol Loading; Environmental Chemistry and Pollution; Turbulence and Sate Variables; Clouds and Climate Upcoming Lidar Programs in India for Climate Studies Thoughts to Think Tank and Future Scope

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5 Lidar Configurations

6 Aerosol and Gas Profiling Facilities (Active Remote Sensors) Bi-static, Helium-Neon Lidar Bi-static, Multi-wavelength Argon-ion Lidar Argon-ion Pumped Dye Lidar Mono-static Excimer DIAL TEA Pulsed CO 2 Lidar Dual Polarization Micro Pulse Lidar (DPMPL) Doppler Wind Lidar Multi-Parameter Raman Lidar

7 Bi-static Argon-ion Lidar with Newtonian Telescope Equipped with Detection and Data Acquisition Systems UV DIAL Ozone Profiler with Alt- Azimuth Cassegrain Telescope Equipped with Detection and Data Acquisition Systems Portable Doppler Wind Lidar LOS Raman Lidar with Double Monochromator and Fiber Optic Coupling Dual Polarization Micro Pulse Lidar with Built-in Polarization Flipper Multi-parameter Raman Lidar Profiler Active Remote Sensing Facilities

8 Atmospheric Lidar Facilities and their Applications * Helium-Neon Lidar (632.8 nm) * Multi-wavelength Argon Ion Lidar (514.5, 501.5, 496.5, 488.0, nm) * Argon ion pumped Dye lidar [( nm (Rhodamin 6G) & nm (Pyridin I)] * Tunable Carbon dioxide lidar ( m) * Excimer-Raman DIAL lidar (308 nm & 353 nm) * Dual Polarization Micro Pulse Lidar (532 nm) The Argon ion lidar has Operated during the correlative measurement program of LITE (Lidar In-space Technology Experiment) of NASA in September 1994 and now for CALIPSO, upcoming Megha Operated extensively during the INDOEX, BoBMEX and ARMEX Operating in conjunction with the overhead passes of IRS-P3/P4/P6 Twice-a-week observations of vertical profiles of aerosol concentration using the Argon ion lidar have been in progress since October Using these multi-year data sets, tropospheric aerosol climatology has been established and undertaken several studies.

9 Atmospheric Aerosols TYPES: (i) SOURCES The most complex and least well understood constituents Varied chemical composition (both acid- and water-soluble) Dynamic size range from 10^-3 to 10^2 m diameter Aitken Nuclei or Condensation Nuclei or Transient Nuclei Radius <0.1 m [Play significant roles in Atmospheric Chemistry and Electricity] (ii) Large or Accumulation-mode particles 0.1 < radius < 1.0 m [Earth-Atmosphere Radiation Balance and Climate Change] (iii) Giant or Coarse-mode particles > 1.0 m [Act as Cloud Condensation Nuclei or Ice Nuclei and are important for studies in Cloud Physics] Natural: Anthropogenic: * Gas-to-Particle (Chemical Reaction of variety of particles) * Sea-spray (Marine or Maritime aerosols) * Wind-blown mineral dust particles from arid and semi-arid zones * Organic aerosols from trees and plants * Biological aerosols such as pollens and spores * Smoke emissions from burning of land biota * Stratospheric aerosols due to volcanic eruptions (direct particle and gas phase reactions) * Meteoric debris * Industrial emissions, soot particles (carbonaceous) * Al2O3 and SO2 from aircrafts and rockets * Bio-mass and bio-fuel burning * Transport and vehicular emissions * Land-use pattern changes such as building constructional activities and agricultural activities

10 Photograph of the Lidar Laboratory with Different Laser Systems

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12 [A] [B] [C] Multi-Wavelength Continuous Wave Argon-ion Lidar system. [A]: Laser Source (Transmitter); [B]: Beam Director and [C]: Telescope, Detection and Data Acquisition System (Receiver)

13 Computer-controlled Bi-static Argon-ion Lidar Newtonian telescope - Receiver part of the Lidar System Argon-ion lidar in operation Lidar Dome Equipped with Cassegrain Telescope and Data Acquisition Systems

14 Aerosol Column Content (X10 6 Cm-2) October 1986 September 2006 Intra-Seasonal Variations in Aerosol Loading over Pune

15 Aerosol column content ( X 10 6 ) cm October December 2006 ACC Regression fit Month number Long-term Changes and Trends in Aerosol Loading. Dashed red line indicates polynomial regression fit

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17 Time evolution of mixed and stable layer heights

18 Ventilation Coefficient (m 2 s -1 ) Mixed Layer Height (m) Ventilation Coefft. Mixing Depth Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month 300 Variation of monthly mean mixed layer heights and corresponding ventilation coefficients observed during over Pune

19 Optical Layout of Laser Scintillometer

20 Aerosol-Cloud-Climate Interactions Aerosols Clouds Climate

21 Cloud Lidar Principle

22 Cloud Profiling using Argon-ion Lidar

23 BEAM EXPANDER /2 WAVE PLATE POLARIZATION FLIPPER 1 Hz to 5 KHz 14" DIA. SCHMIDT CASSEGRAIN TELESCOPE BEAM SPLITTER DPSS LASER DEPOLARIZING OPTICS FILTER PMT1 H.V. MONITOR ENERGY METER COMPUTER PRINTER V PMT SUPPLY FILTER PMT2 * M C S 2 M C S 1 FEEDBACK AND VOLTAGE CONTROL DUAL CHANNEL PHOTON COUNTER DUAL CHANNEL MULTI- CHANNEL SCALER Optical Layout of Dual Polarization Micro Pulse Lidar (DPMPL). Bore-sight mechanism, Octopus and Pockels cell are some of the novel features of the system

24 Main Specifications of Dual Polarization Micro Pulse Lidar (DPMPL) Transmitter Laser type: DPSS Nd:YAG Laser wavelength: 532 nm Laser Repetition Rate: 2 KHz Laser Pulse Energy: 20 J/pulse Laser Pulse Width: 18 ns Laser Beam Expansion: > 20 Polarization Flipper: Alternate parallel and perpendicular Polarization Switching: 1 KHz Receiver Telescope type: 30-cm (12 inch) Schmidt Cassegrain Focal Ratio: f / 10 Filter Bandwidth: 0.6 nm Detection: Dual Channel MCS with metal package PMTs in photon count mode FOV overlapping: Octopus (4 Quadrant PSD), High Performance Remote Terminal Unit Range Resolution: 30 cm

25 Dual Pol Micro Pulse Lidar (DPMPL)

26 Dual Polarization Micro Pulse Lidar (DPMPL) Time evolution of NBL and Residual layer and aerosol plumes Time evolution of Linear Depolarization Ratio (LDR) observed in the night intervening between 30 and 31 December Smaller LDR values in the surface layer almost from mid-night to early morning hours indicate relatively more isotropic aerosol particles than in the NBL over the experimental site.

27 Typical profiles of nocturnal boundary layer and stratiform cloud evolution observed with DPMPL during south-west monsoon 2008

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30 Principle of DIAL (DIfferential Absorption Lidar) or DASE (Differential Absorption Scattering Energy) Technique

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32 Block Diagram of XeCl (Xenon Chloride) Excimer Ozone Lidar System

33 Photograph Showing the Excimer Laser, Raman Cell and Beam Expander-cum-Collimator

34 Photograph Displaying the Lidar Telescope, Detection and Data Acquisition / Processing Systems

35 Altitude (Km) December Hrs Wind Gradiant (S -1 ) x x x x x x x x10 12 Ozone Number Density (cm -3 ) 0 Vertical distributions of DIAL ozone and their association with height gradients of wind speed (open circles) derived from concurrent pilot-balloon observations on December 18, 2003

36 Total Column Ozone (DU) /11/03 20/11/03 21/11/03 25/11/03 27/11/03 28/11/03 29/11/03 Date MICROTOPS LIDAR TOMS Comparison of total ozone determined from Microtops, Lidar and TOMS

37 TEA Carbon Dioxide Tunable Laser System

38 Schematic of the Raman lidar set-up for LOS monitoring of atmospheric NO 2, CO 2 and CH 4. Corresponding shifted wavelengths are 535, 554 and 605 nm at 515 nm

39 LOS Raman Lidar Photograph showing the receiver consisting of 25cm-diameter astronomical quality Newtonian telescope fitted with Peltier-cooled Photo Multiplier Tube and holographic grating-based double monochromator with fiber optic coupling of the Raman-Lidar set up at IITM, Pune

40 Laser Return Signal Strength (mv) nm (Ar + ) Date:9/1/2006 Time:2032 Hrs Scan range = nm Spectral resolution of scan=2nm nm (NO 2 ) 554 nm (CO 2 ) 605 nm (CH 4 ) Wavelength (nm) Typical record of LOS Raman Lidar

41 Main Specifications of Doppler Wind Lidar

42 Compact (65 Kg) Doppler Wind Lidar. The system provides 3D wind field during all sky and weather conditions.

43 DOPPLER WIND LIDAR Height Time evolution of signalto-noise-ratio recorded on 15/07/2010. Cirrus cloud signatures Up to 12 km can be noted from the figure. Height Time evolution of horizontal wind recorded on 15/07/2010. Wind structures within the cloud up to 12 km can be noted from the figure.

44 DPMPL Investigation of Recharging of Atmosphere July 03, 2007 Time-height cross-section of the noise-corrected Back-scattered signal strength profiles obtained with p (co-polarization) and s (cross-polarization) channels of the DPMPL from around 2015 to 2200 LT on July 03, The gap in the record corresponds to drizzle for about 11 minutes. The delay (about 7 minutes) in revival of cloud activity followed by this (recharging of atmosphere) over the site may be noted.

45 CALIPSO Date: August 9, 2007 Validation Total attenuated back scattered signal Perpendicular attenuated backscatter 5 km 0 km Depolarization Pune region Pune region Pune region Cloud-Aerosol Lidar and Infrared Pathfinder Spaceborne Observations (CALIPSO) Validation Experiments on 9 and 11 August 2007 at IITM, Pune, India using DPMPL

46 The low-level clouds observed with DPMPL and CALIPSO at 02:30 hrs on 31 May 2008

47 Indian Lidar Network (I-Link) Right now, a few Research Organizations and a very few Universities have stationary/ mobile lidar systems for monitoring aerosols, gases and temperature in the boundary layer, free-troposphere and stratosphere. In addition, a well-planned program to establish country-wide network of micro pulse lidars for regular monitoring of aerosols, pre-cursor gases and clouds up to the UTLS region has been drawn. Some of these lidars are also being planned to be operated in conjunction with ST Radars/Doppler Sodars for better characterization of aerosols and clouds in terms of their radiative forcing in regional climate diagnosis and prediction programs. Space Borne Lidar (SBL) An ISRO project, as a National Program, called Aerosol Cloud Climatology Laser Radar in Mission to Space (ACCLAIMS) has been undertaken to study the role of aerosols, gases and clouds in the atmosphere-land-ocean interactions. The pilot experiment has been successfully conducted to test the performance of the payload Backscatter Lidar with the National Balloon Facility in Hyderabad. Altitude: 600 km; No. of orbits per day: 15; Wavelengths: 532 and 1064 nm Height resolution: ~ 30 m

48 SOME THOUGHTS AND FUTURE SCOPE Laser Radar (LIDAR) technique augments humanity s ability to study aerosols, trace gas chemistry, clouds and state variables, joining in-situ instruments in both complementary and unique ways for environmental monitoring and climate studies. There is still much work to be done to bring the field maturity. Besides the stationary systems, new generation mobile profilers need to be developed for multi-dimensional mapping of aerosols and gases in different environments. Such systems in network mode will play a vital role in the identification of sources/sinks and modeling of the impacts of aerosols and gases on air pollution, hydrological cycle, weather and climate. Modeling techniques need to be developed for better laser sources with wide tunability and more portability.

49 Thank you all for Attention