Working progress

Li Du

JJA-aggregated over 2000 to 2005

JJA-aggregated over 2000 to 2005

DJF-aggregated over 2000 to 2005

ASOS vs AIRNOW comparison

• Time period: 2010-05-01 to 2010-06-01

• ASOS: 1-min resolution visibility data hourly average

VS. AIRNOW: hourly PM2.5 data

Adopted RH Correction Curve (To be validated for different locations/seasons)

Correction factor: C=8E-08*RH^4-7E-06*RH^3+0.0003*RH^2-0.0032*RH+1.0046

Adopted from Evaluation of the Light Scattering Data from the ASOS Network(ppt) by Rudolf B Husar

RH is calculated from T – Temperature, deg C and D – Dewpoint, deg C

RH = 100*((112-(0.1*T)+D)/(112+(0.9*T)))8

Selected sites:Orangeburg (33.46167 -79.1419) from ASOS and Cape Romain (32.94167 -79.6578) from AIRNOW Approximated 75 km apart

What’s next…(tentative plan)

• Humidity correction of GSOD as well as ASOS data sets through programming so that the corrected version could be viewed in the browser

• Importing more ASOS data (for most sites there are only less than one year’s data) and make some comparisons between aggregated data