TITLE: Surface Aerosol Nephelometer data [3 wavelength] AUTHORS: Robert Hoeller(*) Earth Observation Research Center National Space Development Agency of Japan Harumi Island Triton Square, Office tower X 22F 1-8-10 Harumi, Chuo-ku, Tokyo 104-6023, Japan Tel: +81-3-6221-9093; Fax: +81-3-6221-9192 E-mail: hoeller@eorc.nasda.go.jp Mikio Kasahara (PI) Graduate School of Energy Science Kyoto University Gokasho, Uji, Kyoto 611-0011, Japan E-mail: kasahara@uji.energy.kyoto-u.ac.jp Tel: +81-774-38-4411; Fax: +81-774-38-4411 * contact for questions about the data 1.0 DATA SET OVERVIEW: Introduction This readme file contains a description of in-situ aerosol optical properties measured at Yasaka and Uji, Japan during the intensive field phase of the ACE-Asia field project. [A] FILE: YAnephKy2a Measurement period: March 20 through April 5, 2001 Physical location: Yasaka, Tango peninsula, Japan (Long: 35.37 degrees North, Lat: 135.81 degrees East) For additional information please visit: http://aerosol.energy.kyoto-u.ac.jp/~hoeller/ACEmineyama.html [B] FILE: UJInephKy0104 Measurement period: March 20 through April 27, 2001 Physical location: Uji, Japan (Long: 34.90 degrees North; Lat: 135.80 degrees East) 2.0 INSTRUMENT DESCRIPTION: Light scattering and backscattering coefficients were measured with an integrating nephelometer (TSI, Inc., model 3563) at wavelengths 450, 550, and 700 nm. Performance characteristics and calibration of this instrument were described by Andersen et al. (1996). To periodically exclude coarse particles, two inlets were operated alternately with a defined switching time of 5 min (Andersen and Ogren, 1998). For the upper cutoff a cyclon with an aerodynamic cutoff diameter of 10 micron at a flowrate of 16.7 l/min was used, and coarse/fine separation at 1 micron was made with a multi-jet impactor (greased impaction plate to prevent bounce). For the reduction of raw data, which consist of 1-min averaged values of scattering coefficients, as well as truncation correction and calibration we followed Andersen and Ogren (1998). To minimize variations of measured scattering coefficients due to changes in ambient relative humidity, we employed a heated (a few degrees above ambient air temperature) stainless-steel tubing (1 m) on the inlet. Using this inlet the relative humidity in the nephelometer measurement chamber was constantly below 35%. The nephelometer was calibrated with CO2 and particle free air before and after the measurement campaigns, and the change of calibration constants was within 3%. The zero of the nephelometer was checked with particle free air every hour during the whole measurement period. A detailed description of the instrumentation and data reduction methods is given in Hoeller et al. (2000). 3.0 DATA COLLECTION AND PROCESSING: Data were collected at 1-minute time resolution. Raw instrumental data are further processed by excluding each first minute of the 5-min switching period to avoid measuring the aerosol in transition, and the remailing 4-min period is averaged to obtain sub-1 micron and sub-10 micron values. Data are further 1-hour averaged and super-micron scattering coefficients are calculated by subtracting sub-micron from sub-10 micron values. Data with "bad" instrumental status flags were excluded from the dataset, but were nearly non-existing during the observation period. 4.0 DATA FORMAT: Missing value indicator is "NaN". Time refers to the starting time of the averaging period. Column number and descriptions are given below. 1: Date (yyyymmdd) [UTC] 2: Time (hhmmss) [UTC] (starttime) 3: A450/550_10um Angstrom exponent (450/550 nm), D < 10 um 4: A450/550_1um Angstrom exponent (450/550 nm), D < 1 um 5: A450/700_10um Angstrom exponent (450/700 nm), D < 10 um 6: A450/700_1um Angstrom exponent (450/700 nm), D < 1 um 7: A550/700_10um Angstrom exponent (550/700 nm), D < 10 um 8: A550/700_1um Angstrom exponent (550/700 nm), D < 1 um 9: Bsp450_10um Scattering coefficient (450 nm), D < 10 um [Mm^-1] 10: Bsp450_1um Scattering coefficient (450 nm), D < 1 um [Mm^-1] 11: Bsp450_sup Scattering coefficient (450 nm), 1 < D < 10 um [Mm^-1] 12: Bsp550_10um Scattering coefficient (550 nm), D < 10 um [Mm^-1] 13: Bsp550_1um Scattering coefficient (550 nm), D < 1 um [Mm^-1] 14: Bsp550_sup Scattering coefficient (550 nm), 1 < D < 10 um [Mm^-1] 15: Bsp700_10um Scattering coefficient (700 nm), D < 10 um [Mm^-1] 16: Bsp700_1um Scattering coefficient (700 nm), D < 1 um [Mm^-1] 17: Bsp700_sup Scattering coefficient (700 nm), 1 < D < 10 um [Mm^-1] 18: Bbsp450_10um Backscattering coefficient (450 nm), d < 10 um [Mm^-1] 19: Bbsp450_1um Backscattering coefficient (450 nm), d < 1 um [Mm^-1] 20: Bbsp450_sup Backscattering coefficient (450 nm), 1 < D < 10 um [Mm^-1] 21: Bbsp550_10um Backscattering coefficient (550 nm), d < 10 um [Mm^-1] 22: Bbsp550_1um Backscattering coefficient (550 nm), d < 1 um [Mm^-1] 23: Bbsp550_sup Backscattering coefficient (550 nm), 1 < D < 10 um [Mm^-1] 24: Bbsp700_10um Backscattering coefficient (700 nm), d < 10 um [Mm^-1] 25: Bbsp700_1um Backscattering coefficient (700 nm), d < 1 um [Mm^-1] 26: Bbsp700_sup Backscattering coefficient (700 nm), 1 < D < 10 um [Mm^-1] 27: b450_10um Backscatter ratio (450 nm), D < 10 um 28: b450_1um Backscatter ratio (450 nm), D < 1 um 29: b450_sup Backscatter ratio (450 nm), 1 < D < 10 um 30: b550_10um Backscatter ratio (550 nm), D < 10 um 31: b550_1um Backscatter ratio (550 nm), D < 1 um 32: b550_sup Backscatter ratio (550 nm), 1 < D < 10 um 33: b700_10um Backscatter ratio (700 nm), D < 10 um 34: b700_1um Backscatter ratio (700 nm), D < 1 um 35: b700_sup Backscatter ratio (700 nm), 1 < D < 10 um 5.0 REFERENCES: Anderson, T.L., Covert, D.S., Marshall, S.F., Laucks, M.L., Charlson, R.J., Waggoner, A.P., Ogren, J.A., Caldow, R., Holm, R.L., Quant, F.R., Sem, G.J., Wiedensohler, A., Ahlquist, N.A. and T.S. Bates, Performance characteristics of a High-Sensitivity, Three-Wavelength, Total Scatter/Backscatter Nephelometer, J. Atmos. Oceanic Technol., 13, 967-986, 1996. Anderson, T.L. and J.A. Ogren, Determining aerosol radiative properties using the TSI 3563 Integrating Nephelometer, Aerosol Sci. Technol., 29, 57-69, 1998. Hoeller, R., Kasahara, M., and H. Horvath, Aerosol singel-scattering albedo determined by horizontal extinction closure, J. Aerosol Res., Jpn., 15, 246-255, 2000.