Published on September 30, 2007
Influence of Coastal Meteorological Processes on Aerosol Transport : Influence of Coastal Meteorological Processes on Aerosol Transport Sethu Raman Department of Marine, Earth, and Atmospheric Sciences North Carolina State University Outline: Outline United Arab Emirates – Unified Aerosol Experiment (UAE2, 2004) Meteorological and Aerosols Observations Numerical simulation INDOEX (1999) observations Dust transport and the coastal circulations Summary Indian Southwest Monsoon (June – Sep): Indian Southwest Monsoon (June – Sep) Mesoscale Circulations: Mesoscale Circulations Land – Ocean – Land – Atmosphere Interaction Sea breeze Land breeze Land plume Thermal internal boundary layer Diurnal variation Interaction with large scale flow Topography effects Geographic Overview: Geographic Overview Copyright World Sites Atlas (sitesatlas.com) UAE has a very slow upslope from north to south Al-Hajar Mountains in Oman (1500-3000 m) Zagros Mountains in Iran (1500-4300m) Mostly clear skies UAE2 Observation Systems: UAE2 Observation Systems Surface Platforms 50 surface meteorological stations Temperature, dew point, winds, humidity, pressure, precipitation, solar radiation Upper-Air Platforms Radiosonde sites Aircraft Frequency of Sea and Land Breezes: Frequency of Sea and Land Breezes Abu Dhabi Sea Breeze – winds from 225º to 45º for at least four hours Land Breeze – winds from 45º to 225º for at least four hours Data: NCDC Integrated Surface Hourly Observations 1995-2002 9-11 September 2004: 9-11 September 2004 9 Sep: SB: 1pm 115 km offshore 130 km onshore 10 Sep: SB: 1pm 115 km offshore 130 km onshore 11 Sep: SB: 11 am Sea Breeze Animation: Sea Breeze Animation Land Breeze: Land Breeze Slide14: Aerosol profile 80 km offshore Southerly surface offshore winds at noon, Conc. about 2.75 p/cm3 NE winds aloft from Iran, Land Plume 1-2 μm and 2-3 μm data used to estimate dust conc. Slide15: Aerosol profile 80 km offshore Nortwesterly surface onshore winds at 1600 LT, (SB), Conc. about 0.6 p/cm3, lower values Northerly winds aloft from Iran, Land Plume Slide17: Aerosol profile close to coast S – SE surface offshore winds at 1000 LT 700 m PBL ht, Conc. about 4.1 p/cm3 Easterly winds aloft, Land Plume Onshore – 0.6 Offshore, 80 km – 2.75 Offshore, 2 km – 4.1 Slide18: INDOEX DATA PLATFORMS: Aircraft Research Vessels Satellites Surface obs. stations Constant level balloons Northeast Monsoon: Northeast Monsoon Schematic of aerosol and gas transport in the land plume.: Schematic of aerosol and gas transport in the land plume. LAND PLUME STRUCTURE: θv: LAND PLUME STRUCTURE: θv θ v profile taken from R/V Ron Brown on 7 March 1999 over the Arabian Sea. The land plume is defined as an elevated layer where the transport of aerosols and gases take place. Two distinct layers are present: MBL and elevated mixed layer or Land Plume. A and B represent strong capping inversions. LAND PLUME STRUCTURE: LIDAR: LAND PLUME STRUCTURE: LIDAR Downward looking Lidar from research aircraft Mystere on 9 March 1999. Layer of high backscattering (indicating high aerosol concentration) between 800 to 2400 m altitudes. This layer corresponds to the general location of the Land Plume. Elevated Land Plume: Elevated Land Plume Summary: Summary Coastal regions are characterized by two significant features: Development of mesoscale circulations and the development of different air masses In enclosed waters, land-ocean-land interaction determines aerosol concentration near the surface and aloft and has a strong diurnal variation. On a continental scale, a land plume can form above the ocean with a vertical extent of about 3500 m, approximate depth of the upwind land PBL. Aerosol transport is modulated by the coastal circulations and the land plume that forms aloft. Acknowledgements:: Acknowledgements: Naval Research Laboratory National Science Foundation State Climate Office of NC Becky Eager, Mathew Simpson, NCSU Jeff Reid, and Doug Westphal, NRL, Monterey Slide26: Thank You!