Relative humidity and its effect on aerosol optical depth in the vicinity of convective clouds

Transcription

1 Supplementary Material Relative humidity and its effect on aerosol optical in the vicinity of convective clouds O. Altaratz 1, R. Z. Bar-Or 1,2, U. Wollner 1 and I. Koren 1 1 Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, Rehovot, Israel 2 Currently at the Center for Global Change Science and Joint Program of the Science and Policy of Global Change, Massachusetts Institute of Technology, Cambridge, MA, USA. Ilan.Koren@weizmann.ac.il

2 Introduction The 3 tables below present the details of sounding measurements over a period of 12 years ( ), between June and August, from 13 registered World Metrological Organization (WMO) stations (7 continental and 6 maritime). All data is obtained from the Atmospheric Sounding dataset of the University of Wyoming ( Table 1 presents general information about the stations and the cloudy s characteristics. Table 2 presents the findings of the mean RH values and their standard deviation, and the differences in those values between thick and shallow cloudy s. Table 3 presents the results of the radiative transfer calculations, including the details about the change in AOD as a result of changes in the mean RH values and the differences between the RH values in the vicinity of thick vs. shallow cloudy s.

3 Table 1. This contains general information about the 13 selected stations: station name, WMO station number, geo location (latitude and longitude), elevation above sea level, selected measurement time in UTC and local time, the total number of profiles in the selected season and hour for , the number of cloudy profiles. In addition, it presents the information about the cloudy s in the profiles: the calculated mean LCL height above sea level for the selected season and hour, the LCL standard deviation, cloudy mean, cloudy std, and cloudy median value. The data represents day time measurements during June-July-August, between The maritime stations are indicated by a gray background. Station WMO Station # Location (lat, long) Elev. Time UTC Time LT Lihue, Hawaii , Z 2pm Hilo, Hawaii , Z 2pm Le Raizet, Guadeloupe , Z 8pm Lord Howe Island, Australia # of profiles # of cloudy profiles Mean LCL LCL std mean std median , Z 11am Naze-Funchatoge, Japan , Z 9am Noumea, New Caledonia , Z 11am Lake Charles, Louisiana , Z 6pm Nashville, Tennessee , Z 7pm Manaus, Brazil , Z 8pm Blacksburg, Virginia , Z 7pm Pittsburgh, Pennsylvania , Z 8pm Stuttgart, Germany , Z 1pm Jokioinen, Finland , Z 2pm

4 Table 2. The findings for the 13 selected stations: mean RH values in s of 1 and 2 km - and the matching standard deviation for the 2 s -. The difference in the mean relative humidity values in the lower cloudy atmosphere for 1 and 2 km s, between the deeper cloudy s (their is deeper than the median) and the shallower cloudy s - (RH 1km ), (RH 2km ) (%). The maritime stations are indicated by a gray background. Station (%) (%) (RH 1km) (%) (%) (%) (RH 2km) (%) Lihue, Hawaii Hilo, Hawaii Le Raizet, Guadeloupe Lord Howe Island, Australia Naze-Funchatoge, Japan Noumea, New Caledonia Lake Charles, Louisiana Nashville, Tennessee Manaus, Brazil Blacksburg, Virginia Pittsburgh, Pennsylvania Stuttgart, Germany Jokioinen, Finland

5 Table 3. The findings of the radiative transfer simulations. The calculated changes in AOD - Δ(AOD) (%): (a) based on the standard deviation of the mean RH values in 1 and 2 km, and (b) based on the difference in the mean relative humidity values in the lower cloudy atmosphere (up to 1 and 2 km from the surface), between deeper cloudy s (their is deeper than the median), and shallower cloudy s ( (RH 1km ), (RH 2km )). The radiation transfer calculations use sea-salt like aerosol with a high hygroscopic value (κ=0.7) and biomass burning like aerosol with a low hygroscopic value (κ=0.3). The maritime stations are indicated by a gray background. Maritime Δ(AOD) (%) Δ(AOD) (%) Δ(AOD) (%) Δ(AOD) (%) κ= % 6% 26% 11% κ= % 6% 28% 11% Continental Δ(AOD) (%) Δ(AOD) (%) Δ(AOD) (%) Δ(AOD) (%) κ= % 4% 22% 5% κ= % 5% 22% 4%