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:

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:

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:

1.0DATA SET OVERVIEW

The dataset are measurements of aerosol light scattering and backscattering as a function of relative humidity (RH) for RH between ~40[p1] 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.

2.0INSTRUMENT 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.

3.0DATA 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.[p2]

Growth Type

/ Equation

Monotonic (increasing and decreasing RH)

/

Deliquescent

(Increasing RH) /

Deliquescent (decreasing RH)

/

4.0DATA 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 –90 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=0º 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 0º 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

5.0DATA 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.

6.0REFERENCES

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.

[p1]Actually is around 36%

[p2]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%.