The United Arab Emirates Unified Aerosol Experiment: Investigations into the properties of heterogeneous environments

Transcription

1 The United Arab Emirates Unified Aerosol Experiment: Investigations into the properties of heterogeneous environments Jeffrey S. Reid, Stuart J. Piketh, Brent N. Holben, Douglas L. Westphal, Abdulla Al Mandoos, Roelof Bruintjes And a Cast of 50+ NCAR

2 UAE 2 in a Nutshell Excellent local resources and development through DWRS Micro-synoptic meteorology, microphysics, radiative transfer Papers currently being submitted to JGR special issue Assets SA Aerocommander Aircraft (70 hrs) NRL MAARCO: Coast NASA SMART: Inland desert 5 Doppler radars Met 15 AERONET sites Super 15 Satellite sensors 52 Surface stations 4 Mesoscale models COAMPS NRL deployed MAARCO to the area, and this mobile MM5&MM5 laboratory RTTDA collected Sun Photometer+Met data along with 15 AERONET Sun photometer stations, WRFtwo radiation and aerosol super sites, and a research aircraft. 1 Global model (NAAPS)

3 Participating Institutions Dept. of Water Resources, Office of the President, United Arab Emirates Desert Research Institute, Univ. of Nevada Droplet Measurement Technologies, Inc Jet Propulsion Laboratory, Pasadena, CA National Center for Atmospheric Research, Boulder CO NASA Goddard Space Flight Center, Greenbelt MD Naval Postgraduate School, Monterey, CA Naval Research Laboratory, Monterey, CA Naval Research Laboratory, Stennis, CA North Carolina State University, Raleigh, NC Oman Weather Service Orsmond Aviation, South Africa. Scripps Institution of Oceanography South African Weather Agency TNO Physics and Electronics Laboratory, The Hague, Netherlands Universite de Shebrooke, Sherbrooke, Quebec, Canada University of Alabama, Huntsville, AL University of California, Davis, CA University Corporation for Atmospheric Research University of Hawaii, Honolulu HI University of Lille, France University of Maryland Baltimore County (GEST), Baltimore MD University of Maryland, Collage Park, MD University of Muscat, Oman University of Witwatersrand, South Africa Warsaw University, Warsaw, Poland

4 Aerosol Mass Concentration and Optical Depth at MAARCO Aerosol Optical Thickness (500 nm) Mass Concentration (ug m -3 ) and O'Neill Fine Mode Fraction (η) AOT η C oarse M ode P M Aug/8 Aug/22 Sep/5 Sep/19 Oct/3 High periodic levels of both dust and pollution Aerosol optical depth fine mode fraction varies between 0.2 to 0.8 for high AOTs (>0.4 at 500 nm)

5 Variable Source Regions Northwesterly flow brings dust from Iraq. Sept 12th Northwesterly flow coupled to strengthening of Indian Monsoon Somali Jet Indian Monsoonal Trough

6 Aircraft Observations: NW Flow T d T Sept 1 (a) θ e Strong stable MBL develops over the AG Altitude (m) Oct T, T d, θ e ( o C) Fine Mode (µg m -3 ) Dust (µg m -3 )

7 Variable Source Regions Southwesterly flow brings dust from Interior: Sept 8 Weakening Indian Monsoon results in southwesterly winds l a n o t so e il J on a M m an o S ndi d fi e n o e k up a e ak W re B h g u o Tr

8 Aircraft Observations: SW Flow: Well mixed and developed boundary layer Altitude (m) T d Aug. 28 T Sept. 8 (a) θ e Dust and pollution can be mixed or separated by inversion T, T d, θ e ( o C) Fine Mode (µg m -3 ) Dust (µg m -3 )

9 Example Result 1: Dust Size is Source Region Specific Dust size distributions always fell into one of 4 distinct groups. This corresponded to specific source regions and particle chemistries regardless of production wind speed and transport characteristics. 1 (a) 5 (a) dv aei /d Lnd aei Volume Medain Diameter (µm) Iraq UAE Regional Yemen Interior Indicated Aerodynamic Diameter, d ae (µm) Northern UAE/Iran TSP Ca:Fe Ratio Reid et al., Dynamics of Southwest Asian Dust Particle Size Characteristics with Implications for Global Dust Research, JGR Submitted

10 Example Result 2: Major Revision to AERONET Retrievals Version 2: SSA Dust Dominated Significant Pollution Eck et al., Spatial and Temporal Variability of Column Integrated Aerosol Optical Properties in the Southern Arabian Gulf and United Arab Emirates in Summer, submitted JGR

11 Example Result 3: Satellite Cal Val for dusty, bright and heterogeneous environments New algorithms look very good. MODIS: Kuciauskas Deep Blue: Hsu MISR: Kahn MAARCO AVHRR N16/17: Kuciauskas AATSR: Schoemaker Quickbird: Vincent Plus: CERES, AMSU A/B, AMSR-E, HIRS, AIRS, Meteosat-5/MSG

12 Distinct Regional Aerosol Air Mass Types Identified Dust + Pollution: UAE2 Campaign MISR Data, R. Kahn September 01, 2004 Orbit Path 162 Blocks V Dalma MAARCO Dalma 1 MAARCO 2 Mezaira Mezaira MISR 26 f Image MISR AOT Angstrom Exponent SSA Fract. Spherical Approximately five air masses : Higher ANG --> Lower SSA West Side (including Dalma): Spherical, clean + Dust mixtures dominate East Side (includes Sir Bu Nuair, MAARCO off swath): More Pollution, less Dust

13 Example Result 4: Comprehensive Study of Haboobs, Miller et al. JGR: Haboobs are significant in regional dust budget Low Clouds Haboob Dust Front Motion calculations: Convective cell: 7.1 ms-1 Haboob: 8.8 ms-1

14 UAE 2 : Summary of key results SW Asia is a crossroads of 5+ sub-continents. Aerosol sources in all of these regions need to be modeled well (Walker et al.). Pollution is every bit as important as dust for AOT and forcing in the region. Particles are mostly ammonium bi-sulfate/h 2 SO 4 with some black carbon. Very few organics. (Ross et al.). Micro-meso-synoptic meteorology are all present. Mesoscale features are extremely important in the regional dust budget. (Miller et al.; Eager et al.) Previous descriptions of how particle vertical distributions relate to the inversions is grossly oversimplified. (Reid et al.; Walker et al.). Next generation of over-desert AOT algorithms have been tested (Hsu et al., Kahn et al., Kuciauskas et al., Schoemaker et al., Vincent et al.) SW Asian dust high in evaporates. Implication: Dust is a good CCN, and may have some hygroscopic growth; not surprising since dust is frequently from saline beds. (E. A. Reid et al.)