Regional Atmospheric Measurement Modeling and Prediction Program (RAMMPP)

Summer 2001 Aircraft Research Update for: July 25

It has been a busy several days for the Maryland research aircraft, initially conducting 5 research flights (RF-38 through RF-42) July 22-23 in the Pittsburgh, PA (PIT) area in support of the DOE-sponsored Upper Ohio River Valley Project (UORVP) and EPA-sponsored 2001 Eastern Supersite intensive (ESP01). Although conditions did not produce high ozone during this period we did observe some interesting features during these flights. Some stratified pollution layering was observed over the PIT area, and these layers were seen to be entrained into the developing planetary boundary layer (PBL) during the course of the afternoon. Also, significant ozone and total aerosol scattering enhancements were observed downwind of the PIT city center, with visibility impaired greatly in some instances. A environmental reporter from the Pittsburgh Post-Gazette, Don Hopey, accompanied us on RF-41 investigating ozone/haze production downwind of PIT.

After characterizing the onset of this brief episode over western Pennsylvania, the focus moved east across the state to Philadelphia, PA (PHL) to support the EPA-sponsored NARSTO Northeast Oxidant and Particle Study (NARSTO/NE-OPS) during the termination phase. A further 5 research flights (RF-43 though RF-47) were conducted July 24-25 but the continued brisk winds and relatively clean conditions did not create much high ozone, although haze was moderate throughout the period. On July 25 despite little regional loading of remnant ozone (around 70 ppbv in the PBL) and ozone/haze precursors observed upwind of PHL in the AM, there was a clear increase in ozone (to around 105 ppbv) directly downwind of PHL over Trenton, NJ (N87) while less than 30 miles away over Camden, NJ (19N) - not downwind of PHL on this day - ozone and haze levels were near seasonal background levels.

Under regional weather conditions considered marginal for ozone and haze formation, clear evidence for the influence of the city center on downwind ozone production was observed over two large Pennsylvania cities, PIT and PHL. The data collected during this event should make for interesting modeling scenario in the future. Flight data and vertical survey spiral detail are available in the 2001 RAMMPP research flight summary. Preliminary flight data files are available upon request from the Principal Investigator. Some photographs taken during this most recent NE-OPS deployment have been added to the Photo Gallery below.

A frontal passage is expected over the mid-Atlantic during the next 36 hours. The current plan is to deploy for NARSTO/NE-OPS back to Philadelphia, PA on Friday July 27 after the front passes and remain on station though Sunday July 29 if weather permits. While in Philadelphia we will base at Philadelphia Jet Center: 215-673-9000 (ask for "N500Z Crew") at PNE and will be staying at the nearby Philadelphia Northeast Doubletree Hotel 215-671-9600.