Brief summaries of aircraft and ground based missions involving the PALMS instrument follow. Select a mission, then choose a date. The resulting graph shows either altitude and latitude for that flight, or meteorological data for ground-based measurements. Next, click on a region of the graph to begin viewing spectra starting at that portion of the flight or day.
WAM made measurements of the chemical composition of individual atmospheric aerosol particles, accompanied by particle sizing, gaseous tracer measurements, very accurate water vapor and total water, radiometric radiance measurements and fast response, and accurate measurements of pressure, temperature, and winds. The objective of the mission was to characterize the chemical composition of individual aerosol particles in the upper troposphere and lower stratosphere as a function of size and gaseous composition of the air.
The WAM mission took place in the Spring of 1998. All six flights using the NASA WB-57F high-altitude research aircraft originated from Ellington Field in Houston, Texas, and covered a latitude range of 9°N to 46°N. Most flights were about six hours in duration. The PALMS instrument collected over 28,000 spectra of individual particles during WAM, the first aircraft mission that the instrument participated in. MJ Mahoney from the NASA Jet Propulsion Laboratory supplied the MTP data which is used to show the tropopause height in the graphs.
|WAM - select a flight to begin viewing spectra|
|19980408||2.25 hr||29N-31N||92W-95W||2187||Test flight from Houston|
|19980409||6 hr||17N-30N||83W-95W||2923||Test flight southeast from Houston - cold soak|
|19980411||6 hr||30N-46N||95W-109W||5316||Science flight northwest from Houston - two dips|
|19980501||5.5 hr||13N-30N||94W-95W||8752||Science flight south from Houston|
|19980504||6.5 hr||9N-30N||94W-95W||10415||Science flight south from Houston|
|19980506||5 hr||29N-45N||89W-95W||6216||Science flight north from Houston|
|19980507||6 hr||29N-35N||73W-95W||7986||Science flight east from Houston|
The ACCENT missions were multi-agency sponsored efforts to investigate the chemistry of rocket and aircraft emissions in the upper troposphere (UT) and lower stratosphere (LS) using the NASA WB-57F high-altitude research aircraft. Dr. Paul Newman, NASA ACCENT describes the mission with many photos, including some taken from the cockpit of the NASA WB-57F showing the exhaust plumes of various rockets that the airplane has encountered. ACCENT is jointly sponsored by the Atmospheric Effects of Aircraft Program (AEAP) and the Rocket Impacts on Stratospheric Ozone (RISO) program, also operating earlier rocket plume intercept missions.
The ACCENT mission took place in the Spring and Fall of 1999, though the PALMS instrument participated in the Fall portion only. Most flights originated from Ellington Field in Houston, Texas. There was a flight south to Costa Rica, with the return flight to Houston occuring the following day. Another flight went west to California to do a "rocket intercept," flying through the exhaust plume of a rocket launch at Vandenburg Air Force Base. The return flight to Houston was about a week later. The main mission objectives were to characterize exhaust emisions from different types of rocket motors, and measure the distribution and characteristics of aerosols in and out of major commercial aviation flight corridors as well as over the Pacific Ocean.
|ACCENT - select a flight to begin viewing spectra|
|19990903||4 hr||29N-39N||92W-97W||??||Test flight|
|19990913||5 hr||29N-33N||80W-95W||6387||East coast survey flight|
|19990915||5.5 hr||29N-32N||80W-95W||5964||Hurricane Floyd over-flight|
|19990917||5.25 hr||29N-34N||95W-97W||2914||Air traffic corridors|
|19990920||5.25 hr||5N-30N||84W-95W||12302||Houston to San Jose, Costa Rica|
|19990921||4.5 hr||10N-30N||82W-95W||9817||Costa Rica to Houston|
|19990922||3.5 hr||28N-33N||95W-100W||3287||Test flight|
|19990924||5 hr||29N-35N||95W-121W||9699||Rocket intercept. Landed at Edwards AFB, CA|
|19991004||3.75 hr||29N-35N||95W-118W||2241||Edwards AFB to Houston|
The ACCENT II mission took place in September of 2000. Mission objectives were: 1) to make detailed measurements of the composition and impact of combustion emissions from a solid rocket motor (SRM) in the lower stratosphere, and 2) to study the mixing and transport in the tropical upper troposphere and lower stratosphere. This mission consisted of seven flights using the NASA WB-57F high-altitude research aircraft. There was a flight to Florida to intercept the exhaust plume from the space shuttle as it blasted off to the international space station. The return flight to Houston was on the following day. Another series of three flights went to Costa Rica one day, south from Costa Rica to reach a latitude of 4°S, and back to Costa Rica on the second day. The third flight returned to Houston.
The Idaho Hill measurements took place in September 1993 during the Tropospheric OH Photochemistry experiment. Several techniques for measuring the OH radical were compared and the chemistry leading to the hydroxyl radical was studied (Mount and Williams, J. Geophys. Res., 102, 6171, 1997). Idaho Hill is at 3070 m (10070 feet) elevation just east of the continental divide. It is about 25 km west-northwest of Boulder and the Denver metropolitan area. The Idaho Hill measurements were the first field measurements of single particle composition. Mass spectra of over 5000 particles were obtained with an early version of the PALMS instrument. Notably, the mass spectrometer resolution was lower than in later measurements and the excimer laser was operated at 248 nm rather than 193 nm.
The Cape Grim measurements were conducted in November-December 1995 during the ACE-1 Aerosol Characterization Experiment. The experiment studied aerosols in a very clean marine location. Our mass spectra helped show that sea salt aerosols are a significant source of cloud condensation nuclei in marine regions with high wind speeds and low sulfate pollution.
For further information, see Cape Grim Baseline Air Pollution Station and ACE-1 Southern Hemisphere Aerosol Characterization Experiment.
The ground version of the PALMS instrument was operated by Dr. Ann Middlebrook and Dr. Shanhu Lee at the EPA Supersite in Atlanta during late summer 1999. Over 500,000 mass spectra of individual particles were recorded.