TITLE: Aerosol light scattering measurements as a function of relative humidity onboard the Ron Brown Version 1.0 AUTHORS: Christian M. Carrico Department of Atmospheric Science Colorado State University Ft. Collins, CO 80523 Tel: 970-491-8667 Fax: 970-491-8483 Email: carrico@lamar.colostate.edu Pinar Kus Department of Civil and Environmental Engineering, MC-250 University of Illinois at Urbana-Champaign Urbana, IL 61801 Tel: 217-333-8692 Fax: 217-333-6968 Email: pinarkus@students.uiuc.edu Mark J. Rood Department of Civil and Environmental Engineering, MC-250 University of Illinois at Urbana-Champaign Urbana, IL 61801 Tel: 217-333-6963 Fax: 217-333-6968 Email: m-rood@uiuc.edu 1.0 DATA SET OVERVIEW The dataset are measurements of aerosol light scattering and backscattering as a function of relative humidity (RH) for RH between ~40 and 85%. The measurements occurred onboard the R/V Ronald Brown from 17 March 2001 through 20 April 2001. The light scattering measurements are at wavelengths of 450, 550, and 700 nm and alternating between upper particle size cuts of 10 and 1 micrometers. Unless otherwise specified the parameters given here are for standard temperature and pressure conditions of 273K and 1013 mbar. 2.0 INSTRUMENT DESCRIPTION Measurements were made with a controlled relative humidity nephelometry system (humidograph) [Carrico et al., 1998; 2000]. Aerosol was sampled from the Ron Brown community aerosol inlet at a height of approximately 20m above sea level and from which instruments in both aerosol vans on the forward deck sampled. The community aerosol inlet was conditioned by heating to ~50% RH to allow size cuts to be imposed at a common RH before sampling by individual instruments. The humidograph includes two TSI 3563 nephelometers with a humidity control system located between the instruments. The first nephelometer, the dry reference nephelometer, is operated at low RH (RH=19 ? 5%) continuously. This was accomplished by additional sample heating to 33.5 ? 1.9?C). An RH control system follows the first nephelometer and scans sample RH by adding water vapor and/or changing temperature. Downstream of the RH controller, the scanning RH nephelometer measures light scattering properties while scanning RH from ~40% to 85%. RH scans are performed with both increasing controlled RH starting from a "dry" state and decreasing RH conditions starting from a hydrated state. A complete increasing and decreasing RH scan (humidogram) is measured in approximately 45 minutes. 3.0 DATA COLLECTION AND PROCESSING Nephelometer calibration occurred approximately every 3 days with CO2 and filtered air. RH and temperature measurements were inter-calibrated before and during the experiment. Measurements with laboratory generated NaCl and (NH4)2SO4 were used during the experiment for validation of instrument operation. Lamp power was decreased and ventilation was increased to diminish the effects of instrumental heating on the measurements. Light scattering and backscattering coefficients as a function of controlled RH are given as f(RH) values for discrete RH values of 35%, 45%, 50%, 60%, 65%, 70%, 75%, 80%, 82%, and 85% . As defined here, f(RH) is the ratio of the measured light scattering coefficient at the indicated controlled RH to the light scattering coefficient at the RH of the dry reference nephelometer (also given in the data file and with average of RH = 19 ? 5%). Based on observed curve structure, measured f(RH) were fit to one of two curves, monotonic or deliquescent as given in the table below [Kotchenruther et al., 1999]. Monotonic curves featured smoothly increasing and decreasing f(RH) that demonstrated similar pathways for increasing and decreasing controlled RH. Deliquescent curves featured step change(s) in f(RH) and demonstrated a hysteresis effect with separate f(RH) pathways for increasing and decreasing controlled RH. Deliquescent step changes are plotted versus RH measured immediately upstream of the scanning RH nephelometer. This is the point where the highest RH is achieved within the humidograph (due to nephelometer heating) and where deliquescence occurs. Curve fit parameters a, b, c, d, and g are given as appropriate for the curve fit for each humidogram. Growth Type Equation Monotonic (increasing and decreasing RH) Deliquescent (Increasing RH) Deliquescent (decreasing RH) 4.0 DATA FORMAT The data file is a column-separated data file that is comma delimited and time stamped at the beginning of each nominal 45 minute period. Unless otherwise noted, the parameters given are for standard temperature and pressure (1013 mbar and 273K). Meteorological parameters (columns 4 through 20) are courtesy of Jim Johnson of NOAA-PMEL and are provided for calculation of the parameters at ambient pressure, temperature, and RH. PMEL light scattering measurements (at RH~50%) are provided for comparative purposes and are courtesy of Trish Quinn and Tim Bates. The final 18 columns give low RH reference light scattering and backscattering coefficient mean values and standard deviations, at ambient temperature and pressure followed by f(RH=ambient). Thus multiplying corresponding low RH ambient scattering with f(RH=ambient) values gives scattering at ambient temperature, pressure, and RH. Parameter names that end with "UP" apply to increasing controlled RH starting from "dry" conditions while those including "DN" apply to decreasing controlled RH starting from a hydrated state. Curve fits that are designated "MON" in the "Growth_Type" column 25 exhibit the same hygroscopic growth behavior for increasing and decreasing controlled RH and thus only one curve fit is given. Curve fits that are designated "DEL" in the "Growth_Type" column 25 exhibit different pathways for increasing and decreasing controlled RH and have distinct curve fits given for increasing RH (UP) and decreasing controlled RH (DN). Each row of the data file gives the following information in the column numbers given below: 1. filename (YMMDDHHfracH) Time stamp UTC filename (for internal bookkeeping) 2. Date_Time_fRHfile (YYYYMMDDHHMM) UTC date and time for the beginning of f(RH) measurement. The complete up/down RH scan lasts approximately 45 minutes. 3. DayOfYear_fRHfile (Decimal Day) Day of year for f(RH) measurement based on 1 Feb 12:00 noon UTC = 32.5 4. Date_Time_MET: (YYYYMMDDHHMM) UTC date and time for the meteorological data 5. DayOfYear_MET (Decimal Day) Day of year for meteorological data based on 1 Feb 12:00 noon UTC = 32.5 6. LAT (Deg) Ship's latitude position in degrees from û90 to +90 degrees 7. LONGT (Deg) Ship's longitude position in degrees from 0 to 360 degrees 8. GPS-course (Deg) Ship's course from 0 to 360 degrees (0=north) 9. GPS-spd (knts) Ship's speed in knots 10. AirT_Ambient (Deg C) ambient air temperature in degrees Celcius 11. RH_Ambient (%) ambient relative humidity in percent 12. Baro (mb) (ambient ?) barometric pressure in millibar 13. Insolation (w m^2) solar flux in watts per square meter 14. WS_rel (m/s) wind speed relative to ship in meters per second 15. WD_rel to bow (deg) wind direction relative to ship direction (-90 port, 0 dead ahead, +90 starboard) 16. WindS (m/s) wind speed relative to ocean surface in meters per second 17. WindD (deg) wind direction relative to ocean surface 18. WindU (m/s) wind to east in meters per second 19. WindV (m/s) wind to north in meters per second 20. RainRate (mm hr-1) rainfall rate in millimeters per hour 21. Size (um) Upper size cut of the measurement (1 or 10 micrometers) 22. PMEL_RH (%) for NOAA-PMEL nephelometer recorded simultaneously 23. PMEL_sp550 (1/Mm) light scattering coefficient in inverse megameters (1/Mm =1e-6/m) at 550 nm for NOAA-PMEL nephelometer for given size cut at T=0¦ C, RH=PMEL_RH, and P=1013 mb. 24. PMEL_Position Determination of whether light scattering measured at RH~50% is on the upper branch of the hysteresis loop (U), lower branch (L), intermediate (75-closer to upper branch, 50 in the middle, 25 closer to the lower branch), on both the upper and lower curves for the case of monotonic growth (B), or an is outlier (O) from the f(RH) curve. This position is used to calculate the ambient f(RH) below. 25. Growth_Type: Curve fit used to measured experimental data. Deliquescent curves (DEL) have step change(s) in light scattering coefficients at deliquescence and crystallization RH values with evidence of hysteresis comparing increasing and decreasing RH scans. Monotonic curves (MON) have smoothly changing light scattering coefficients with little difference between increasing and decreasing RH scans. 26. DRH (%) Deliquescence RH if the curve fit is deliquescent 27. CRH (%) Crystallization RH if the curve fit is deliquescent. Note that if the value -99 for a deliquescent type of growth, CRH value could not be determined. 28. RH_ReferenceNeph (%): RH in the low RH reference nephelometer 29. period (min): Duration over which dry scattering values are reported 30. drysp_450_STP (1/Mm) Low RH light scattering coefficient in inverse megameters (1/Mm =1e- 6/m) at 450 nm (at 0¦ C and 1013 mb) 31. devdrysp_450_STP (1/Mm) Standard deviation of drysp_450_STP 32. drysp_550_STP (1/Mm) Low RH light scattering coefficient at 550 nm 33. devdrysp_550_STP (1/Mm) ) Standard deviation of drysp_550_STP 34. drysp_700_STP (1/Mm) Low RH light scattering coefficient at 700 nm 35. devdrysp_700_STP (1/Mm) Standard deviation of drysp_700_STP 36. drybsp_450_STP (1/Mm) Low RH light back scattering coefficient at 450 nm 37. devdrybsp_450_STP (1/Mm) Standard deviation of drybsp_450_STP 38. drybsp_550_STP (1/Mm) Low RH light back scattering coefficient at 550 nm 39. devdrybsp_550_STP (1/Mm) Standard deviation of drybsp_550_STP 40. drybsp_700_STP (1/Mm) Low RH light back scattering coefficient at 700 nm 41. devdrybsp_700_STP (1/Mm) Standard deviation of drybsp_700_STP 42. a_450sp_UP: Parameter a for curve fit for total scattering at 450 nm 43. b_450sp_UP: Parameter b for curve fit for total scattering at 450 nm 44. d_450sp_UP: Parameter d for curve fit for total scattering at 450 nm 45. c_450sp_UP: Parameter c for curve fit for total scattering at 450 nm 46. g_450sp_UP: Parameter g for curve fit for total scattering at 450 nm 47. RMSE_450sp_UP: Fit root mean square errora for f(RH) at 450 nm 48. Conf90_450sp_UP: Confidence widthb in value of f(RH=90%) for total scattering at 450 nm 49. a_550sp_UP: Parameter a for curve fit for total scattering at 550 nm 50. b_550sp_UP: Parameter b for curve fit for total scattering at 550 nm 51. d_550sp_UP: Parameter d for curve fit for total scattering at 550 nm 52. c_550sp_UP: Parameter c for curve fit for total scattering at 550 nm 53. g_550sp_UP: Parameter g for curve fit for total scattering at 550 nm 54. RMSE_550sp_UP: Fit root mean square error of f (RH) fit for total scattering at 550 nm 55. Conf90_550sp_UP: Confidence width in value of f(RH=90%) for total scattering at 550 nm 56. a_700sp_UP: Parameter a for curve fit for total scattering at 700 nm 57. b_700sp_UP: Parameter b for curve fit for total scattering at 700 nm 58. d_700sp_UP: Parameter d for curve fit for total scattering at 700 nm 59. c_700sp_UP: Parameter c for curve fit for total scattering at 700 nm 60. g_700sp_UP: Parameter g for curve fit for total scattering at 700 nm 61. RMSE_700sp_UP: Fit root mean square error of f(RH) fit for total scattering at 700nm 62. Conf90_700sp_UP: Confidence width in value of f(RH=90%) for total scattering at 700nm 63. a_450bsp_UP: Parameter a for curve fit for back scattering at 450 nm 64. b_450bsp_UP: Parameter b for curve fit for back scattering at 450 nm 65. d_450bsp_UP: Parameter d for curve fit for back scattering at 450 nm 66. c_450bsp_UP: Parameter c for curve fit for back scattering at 450 nm 67. g_450bsp_UP: Parameter g for curve fit for back scattering at 450 nm 68. RMSE_450bsp_UP: Fit root mean square error of f (RH) fit for back scattering at 450 nm 69. Conf90_450bsp_UP: Confidence width in value of f(RH=90%) for back scattering at 450 nm 70. a_550bsp_UP: Parameter a for curve fit for back scattering at 550 nm 71. b_550bsp_UP: Parameter b for curve fit for back scattering at 550 nm 72. d_550bsp_UP: Parameter d for curve fit for back scattering at 550 nm 73. c_550bsp_UP: Parameter c for curve fit for back scattering at 550 nm 74. g_550bsp_UP: Parameter g for curve fit for back scattering at 550 nm 75. RMSE_550bsp_UP: Fit root mean square error of f (RH) fit for back scattering at 550 nm 76. Conf90_550bsp_UP: Confidence in value of f(RH=90%) for back scattering at 550 nm 77. a_700bsp_UP: Parameter a for curve fit for back scattering at 700 nm 78. b_700bsp_UP: Parameter b for curve fit for back scattering at 700 nm 79. d_700bsp_UP: Parameter d for curve fit for back scattering at 700 nm 80. c_700bsp_UP: Parameter c for curve fit for back scattering at 700 nm 81. g_700bsp_UP: Parameter g for curve fit for back scattering at 700 nm 82. RMSE_700bsp_UP: Fit root mean square error of f (RH) fit for back scattering at 700 nm 83. Conf90_700bsp_UP: Confidence width in value of f (RH=90%) 84. UPfitfRH_450sp_35: f (RH=35%) value for total scattering at 450 nm 85. UPfitfRH_450sp_45: f (RH=45%) value for total scattering at 450 nm 86. UPfitfRH_450sp_50: f (RH=50 %) value for total scattering at 450 nm 87. UPfitfRH_450sp_60: f (RH=60%) value for total scattering at 450 nm 88. UPfitfRH_450sp_65: f (RH=65%) value for total scattering at 450 nm 89. UPfitfRH_450sp_70: f (RH=70%) value for total scattering at 450 nm 90. UPfitfRH_450sp_75: f (RH=75%) value for total scattering at 450 nm 91. UPfitfRH_450sp_80: f (RH=80%) value for total scattering at 450 nm 92. UPfitfRH_450sp_82: f (RH=82%) value for total scattering at 450 nm 93. UPfitfRH_450sp_85: f (RH=85%) value for total scattering at 450 nm 94. UPfitfRH_550sp_35: f (RH=35%) value for total scattering at 550 nm 95. UPfitfRH_550sp_45: f (RH=45%) value for total scattering at 550 nm 96. UPfitfRH_550sp_50: f (RH=50%) value for total scattering at 550 nm 97. UPfitfRH_550sp_60: f (RH=60%) value for total scattering at 550 nm 98. UPfitfRH_550sp_65: f (RH=65%) value for total scattering at 550 nm 99. UPfitfRH_550sp_70: f (RH=70%) value for total scattering at 550 nm 100. UPfitfRH_550sp_75: f (RH=75%) value for total scattering at 550 nm 101. UPfitfRH_550sp_80: f (RH=80%) value for total scattering at 550 nm 102. UPfitfRH_550sp_82: f (RH=82%) value for total scattering at 550 nm 103. UPfitfRH_550sp_85: f (RH=85%) value for total scattering at 550 nm 104. UPfitfRH_700sp_35: f (RH=35%) value for total scattering at 700 nm 105. UPfitfRH_700sp_45: f (RH=45%) value for total scattering at 700 nm 106. UPfitfRH_700sp_50: f (RH=50%) value for total scattering at 700 nm 107. UPfitfRH_700sp_60: f (RH=60%) value for total scattering at 700 nm 108. UPfitfRH_700sp_65: f (RH=65%) value for total scattering at 700 nm 109. UPfitfRH_700sp_70: f (RH=70%) value for total scattering at 700 nm 110. UPfitfRH_700sp_75: f (RH=75%) value for total scattering at 700 nm 111. UPfitfRH_700sp_80: f (RH=80%) value for total scattering at 700 nm 112. UPfitfRH_700sp_82: f (RH=82%) value for total scattering at 700 nm 113. UPfitfRH_700sp_85: f (RH=85%) value for total scattering at 700 nm 114. UPfitfRH_450bsp_35: f (RH=35%) value for back scattering at 450 nm 115. UPfitfRH_450bsp_45: f (RH=45%) value for back scattering at 450 nm 116. UPfitfRH_450bsp_50: f (RH=50%) value for back scattering at 450 nm 117. UPfitfRH_450bsp_60: f (RH=60%) value for back scattering at 450 nm 118. UPfitfRH_450bsp_65: f (RH=65%) value for back scattering at 450 nm 119. UPfitfRH_450bsp_70: f (RH=70%) value for back scattering at 450 nm 120. UPfitfRH_450bsp_75: f (RH=75%) value for back scattering at 450 nm 121. UPfitfRH_450bsp_80: f (RH=80%) value for back scattering at 450 nm 122. UPfitfRH_450bsp_82: f (RH=82%) value for back scattering at 450 nm 123. UPfitfRH_450bsp_85: f (RH=85%) value for back scattering at 450 nm 124. UPfitfRH_550bsp_35: f (RH=35%) value for back scattering at 550 nm 125. UPfitfRH_550bsp_45: f (RH=45%) value for back scattering at 550 nm 126. UPfitfRH_550bsp_50: f (RH=50%) value for back scattering at 550 nm 127. UPfitfRH_550bsp_60: f (RH=60%) value for back scattering at 550 nm 128. UPfitfRH_550bsp_65: f (RH=65%) value for back scattering at 550 nm 129. UPfitfRH_550bsp_70: f (RH=70%) value for back scattering at 550 nm 130. UPfitfRH_550bsp_75: f (RH=75%) value for back scattering at 550 nm 131. UPfitfRH_550bsp_80: f (RH=80%) value for back scattering at 550 nm 132. UPfitfRH_550bsp_82: f (RH=82%) value for back scattering at 550 nm 133. UPfitfRH_550bsp_85: f (RH=85%) value for back scattering at 550 nm 134. UPfitfRH_700bsp_35: f (RH=35%) value for back scattering at 700 nm 135. UPfitfRH_700bsp_45: f (RH=45%) value for back scattering at 700 nm 136. UPfitfRH_700bsp_50: f (RH=50%) value for back scattering at 700 nm 137. UPfitfRH_700bsp_60: f (RH=60%) value for back scattering at 700 nm 138. UPfitfRH_700bsp_65: f (RH=65%) value for back scattering at 700 nm 139. UPfitfRH_700bsp_70: f (RH=70%) value for back scattering at 700 nm 140. UPfitfRH_700bsp_75: f (RH=75%) value for back scattering at 700 nm 141. UPfitfRH_700bsp_80: f (RH=80%) value for back scattering at 700 nm 142. UPfitfRH_700bsp_82: f (RH=82%) value for back scattering at 700 nm 143. UPfitfRH_700bsp_85: f (RH=85%) value for back scattering at 700 nm 144. c_450sp_DN: Parameter c for curve fit for total scattering at 450 nm 145. g_450sp_DN: Parameter g for curve fit for total scattering at 450 nm 146. RMSE_450sp_DN: Fit root mean square errora for f(RH) at 450 nm 147. Conf90_450sp_DN: Confidence widthb in value of f(RH=90%) for total scattering at 450 nm 148. c_550sp_DN: Parameter c for curve fit for total scattering at 550 nm 149. g_550sp_DN: Parameter g for curve fit for total scattering at 550 nm 150. RMSE_550sp_DN: Fit root mean square error of f (RH) fit for total scattering at 550 nm 151. Conf90_550sp_DN: Confidence width in value of f(RH=90%) for total scattering at 550 nm 152. c_700sp_DN: Parameter c for curve fit for total scattering at 700 nm 153. g_700sp_DN: Parameter g for curve fit for total scattering at 700 nm 154. RMSE_700sp_DN: Fit root mean square error of f(RH) fit for total scattering at 700nm 155. Conf90_700sp_DN: Confidence width in value of f(RH=90%) for total scattering at 700nm 156. c_450bsp_DN: Parameter c for curve fit for back scattering at 450 nm 157. g_450bsp_DN: Parameter g for curve fit for back scattering at 450 nm 158. RMSE_450bsp_DN: Fit root mean square error of f (RH) fit for back scattering at 450 nm 159. Conf90_450bsp_DN: Confidence width in value of f(RH=90%) for back scattering at 450 nm 160. c_550bsp_DN: Parameter c for curve fit for back scattering at 550 nm 161. g_550bsp_DN: Parameter g for curve fit for back scattering at 550 nm 162. RMSE_550bsp_DN: Fit root mean square error of f (RH) fit for back scattering at 550 nm 163. Conf90_550bsp_DN: Confidence in value of f(RH=90%) for back scattering at 550 nm 164. c_700bsp_DN: Parameter c for curve fit for back scattering at 700 nm 165. g_700bsp_DN: Parameter g for curve fit for back scattering at 700 nm 166. RMSE_700bsp_DN: Fit root mean square error of f (RH) fit for back scattering at 700 nm 167. Conf90_700bsp_DN: Confidence width in value of f (RH=90%) for back scattering at 700 nm 168. DNfitfRH_450sp_35: f (RH=35%) value for total scattering at 450 nm 169. DNfitfRH_450sp_45: f (RH=45%) value for total scattering at 450 nm 170. DNfitfRH_450sp_50: f (RH=50 %) value for total scattering at 450 nm 171. DNfitfRH_450sp_60: f (RH=60%) value for total scattering at 450 nm 172. DNfitfRH_450sp_65: f (RH=65%) value for total scattering at 450 nm 173. DNfitfRH_450sp_70: f (RH=70%) value for total scattering at 450 nm 174. DNfitfRH_450sp_75: f (RH=75%) value for total scattering at 450 nm 175. DNfitfRH_450sp_80: f (RH=80%) value for total scattering at 450 nm 176. DNfitfRH_450sp_82: f (RH=82%) value for total scattering at 450 nm 177. DNfitfRH_450sp_85: f (RH=85%) value for total scattering at 450 nm 178. DNfitfRH_550sp_35: f (RH=35%) value for total scattering at 550 nm 179. DNfitfRH_550sp_45: f (RH=45%) value for total scattering at 550 nm 180. DNfitfRH_550sp_50: f (RH=50%) value for total scattering at 550 nm 181. DNfitfRH_550sp_60: f (RH=60%) value for total scattering at 550 nm 182. DNfitfRH_550sp_65: f (RH=65%) value for total scattering at 550 nm 183. DNfitfRH_550sp_70: f (RH=70%) value for total scattering at 550 nm 184. DNfitfRH_550sp_75: f (RH=75%) value for total scattering at 550 nm 185. DNfitfRH_550sp_80: f (RH=80%) value for total scattering at 550 nm 186. DNfitfRH_550sp_82: f (RH=82%) value for total scattering at 550 nm 187. DNfitfRH_550sp_85: f (RH=85%) value for total scattering at 550 nm 188. DNfitfRH_700sp_35: f (RH=35%) value for total scattering at 700 nm 189. DNfitfRH_700sp_45: f (RH=45%) value for total scattering at 700 nm 190. DNfitfRH_700sp_50: f (RH=50%) value for total scattering at 700 nm 191. DNfitfRH_700sp_60: f (RH=60%) value for total scattering at 700 nm 192. DNfitfRH_700sp_65: f (RH=65%) value for total scattering at 700 nm 193. DNfitfRH_700sp_70: f (RH=70%) value for total scattering at 700 nm 194. DNfitfRH_700sp_75: f (RH=75%) value for total scattering at 700 nm 195. DNfitfRH_700sp_80: f (RH=80%) value for total scattering at 700 nm 196. DNfitfRH_700sp_82: f (RH=82%) value for total scattering at 700 nm 197. DNfitfRH_700sp_85: f (RH=85%) value for total scattering at 700 nm 198. DNfitfRH_450bsp_35: f (RH=35%) value for back scattering at 450 nm 199. DNfitfRH_450bsp_45: f (RH=45%) value for back scattering at 450 nm 200. DNfitfRH_450bsp_50: f (RH=50%) value for back scattering at 450 nm 201. DNfitfRH_450bsp_60: f (RH=60%) value for back scattering at 450 nm 202. DNfitfRH_450bsp_65: f (RH=65%) value for back scattering at 450 nm 203. DNfitfRH_450bsp_70: f (RH=70%) value for back scattering at 450 nm 204. DNfitfRH_450bsp_75: f (RH=75%) value for back scattering at 450 nm 205. DNfitfRH_450bsp_80: f (RH=80%) value for back scattering at 450 nm 206. DNfitfRH_450bsp_82: f (RH=82%) value for back scattering at 450 nm 207. DNfitfRH_450bsp_85: f (RH=85%) value for back scattering at 450 nm 208. DNfitfRH_550bsp_35: f (RH=35%) value for back scattering at 550 nm 209. DNfitfRH_550bsp_45: f (RH=45%) value for back scattering at 550 nm 210. DNfitfRH_550bsp_50: f (RH=50%) value for back scattering at 550 nm 211. DNfitfRH_550bsp_60: f (RH=60%) value for back scattering at 550 nm 212. DNfitfRH_550bsp_65: f (RH=65%) value for back scattering at 550 nm 213. DNfitfRH_550bsp_70: f (RH=70%) value for back scattering at 550 nm 214. DNfitfRH_550bsp_75: f (RH=75%) value for back scattering at 550 nm 215. DNfitfRH_550bsp_80: f (RH=80%) value for back scattering at 550 nm 216. DNfitfRH_550bsp_82: f (RH=82%) value for back scattering at 550 nm 217. DNfitfRH_550bsp_85: f (RH=85%) value for back scattering at 550 nm 218. DNfitfRH_700bsp_35: f (RH=35%) value for back scattering at 700 nm 219. DNfitfRH_700bsp_45: f (RH=45%) value for back scattering at 700 nm 220. DNfitfRH_700bsp_50: f (RH=50%) value for back scattering at 700 nm 221. DNfitfRH_700bsp_60: f (RH=60%) value for back scattering at 700 nm 222. DNfitfRH_700bsp_65: f (RH=65%) value for back scattering at 700 nm 223. DNfitfRH_700bsp_70: f (RH=70%) value for back scattering at 700 nm 224. DNfitfRH_700bsp_75: f (RH=75%) value for back scattering at 700 nm 225. DNfitfRH_700bsp_80: f (RH=80%) value for back scattering at 700 nm 226. DNfitfRH_700bsp_82: f (RH=82%) value for back scattering at 700 nm 227. DNfitfRH_700bsp_85: f (RH=85%) value for back scattering at 700 nm 228. drysp_450_AMB (1/Mm) Low RH ambient scattering at 450 nm (scattering at ambient T and P conditions at RH = RH_ReferenceNeph) 229. devdrysp_450_AMB (1/Mm) Standard deviation for drysp_450_AMB 230. drysp_550_AMB (1/Mm) Low RH ambient scattering at 550 nm 231. devdrysp_550_AMB (1/Mm) Standard deviation for drysp_550_AMB 232. drysp_700_AMB (1/Mm) Low RH ambient scattering at 700 nm 233. devdrysp_700_AMB (1/Mm) Standard deviation for drybsp_700_AMB 234. drybsp_450_AMB (1/Mm) Low RH ambient back scattering at 450 nm 235. devdrybsp_450_AMB (1/Mm) Standard deviation for drybsp_450_AMB 236. drybsp_550_AMB (1/Mm) Low RH ambient back scattering at 550 nm 237. devdrybsp_550_AMB (1/Mm) Standard deviation for drybsp_550_AMB 238. drybsp_700_AMB (1/Mm) Low RH ambient back scattering at 700 nm 239. devdrybsp_7000_AMB (1/Mm) Standard deviation for drybsp_700_AMB 240. f(RHamb)_sp450: f(RH=ambient) value for total scattering at 450 nm 241. f(RHamb)_sp550: f(RH=ambient) value for total scattering at 550 nm 242. f(RHamb)_sp700: f(RH=ambient) value for total scattering at 700 nm 243. f(RHamb)_bsp450: f(RH=ambient) value for back scattering at 450 nm 244. f(RHamb)_bsp550: f(RH=ambient) value for back scattering at 550 nm 245. f(RHamb)_bsp700: f(RH=ambient) value for back scattering at 700 nm 5.0 DATA REMARKS a Fit root mean square error: the root mean square error of the regression, which is calculated as the square root of the sum of squares of residuals (difference between observed and predicted value) divided by degrees of freedom. A value closer to zero means a better fit. b Confidence width: defines the width of the confidence interval for the predicted value with a 95% certainty. It means there is a 95% probability that the predicted value actually is within lower (associated value-confidence width) and upper (associated value + confidence width) limit of the confidence interval. For example, an f(RH) value of 2 with a confidence width of 0.3 indicates that the f(RH) value can be between 1.7 and 2.3 with a 95% confidence limit. 6.0 REFERENCES Carrico, C.M., M.J. Rood, and J.A. Ogren, Light scattering properties at Cape Grim, Tasmania, during the First Aerosol Characterization Experiment, J. Geophys. Res., 103, D13, 16,565-16,574, 1998. Carrico, C.M., M.J. Rood, J.A. Ogren, C. Neususs, A. Wiedensohler, and J. Heintzenberg, Aerosol optical properties at Sagres, Portugal, during ACE-2, Tellus, 52B, 694-716, 2000. Kotchenruther, R.A., P.V. Hobbs, and D.A. Hegg, Humidification factors for atmospheric aerosols off the mid-Atlantic coast of the United States, J. Geophys. Res., 104, D2, 2239- 2251, 1999. Actually is around 36% I think it would be good to note that fits for decreasing controlled RH pathway in a Deliquescent type of growth is valid until CRH+5%.