SUbsonic aircraft Contrail & Clouds Effects Special Study (SUCCESS)
Langley DAAC Project/Campaign Document
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SUbsonic aircraft Contrail & Clouds Effects Special Study (SUCCESS)
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SUCCESS is a NASA field program using scientifically instrumented aircraft and ground based measurements to investigate the effects of subsonic aircraft on contrails, cirrus clouds and atmospheric chemistry. The experiment is cosponsored by NASA's Subsonic Assessment Program and the Radiation Sciences Program which are part of the overall Aeronautics and Mission to Planet Earth Programs, respectively. SUCCESS has well over a hundred direct participants from several NASA Centers, other agencies, universities and private research companies.
The SUCCESS project was conducted from the Kansas State University airport facilities in Salina, Kansas from April 8, 1996 until May 10, 1996, with an extension from May 10 until May 15, 1996 at NASA's Ames Research Center in Moffett Field, Ca.
SUCCESS had several objectives:
to better determine the radiative properties of cirrus clouds and of contrails so that satellite observations can more reliably measure their impact on the Earth's radiation budget.
to determine how cirrus clouds form, whether the exhaust from subsonic aircraft presently affects the formation of cirrus clouds, and if the exhaust does affect the clouds whether the changes induced are of climatological significance.
to develop and test several new instruments.
to better determine the characteristics of gaseous and particulate exhaust products from subsonic aircraft and their evolution in the region near the aircraft.
In order to achieve these experimental objectives the NASA DC-8, and T-39 aircraft were used as in situ sampling platforms. The NASA ER-2 aircraft was also employed as a remote sensing platform. The NASA 757 was used as a source aircraft for studies of contrails and exhaust. Table 1 lists the flights that were made by these aircraft.
Table 1: SUMMARY OF SUCCESS FLIGHTS
________________________________________________________________________
Date DC-8 ER-2 T-39 757 CART* Purpose
________________________________________________________________________
4/4 X Test flight
4/8 X Ferry flight
4/10 X Test flight at Ames
4/11 X Transit flight
4/13 X X X DC-8 transit and
contrails, ER-2
Cart site for clear sky
Radiation
4/15 X X X X Coordination practice,
near field sampling and
clear sky radiation
4/16 X X X X Near field sampling by
T-39 Cirrus profiling by
DC-8 radiation
observations of
contrails and cirrus by
ER-2
4/18 X X Xe Near field sampling
without contrails. DC-8
sampled supercooled
water cloud.
4/20 X X X Xe,o T-39 inst. test flight.
ER-2 and DC-8 observed
cirrus clouds with
multiple vertical profiles.
4/21 X X X Vertical profiling of
Cirrus clouds observed
from the top. Contrail
sampling by DC-8.
Studies of convective
clouds
4/23 X ER-2 overflew wave
clouds
4/24 X X X T-39 did near field
sampling of DC-8
exhaust. DC-8 did
vertical profile in cirrus.
4/26 X X T-39 followed
commercial aircraft, ER-2
did satellite underflight.
4/27 X X X Xe,o DC-8 sampled contrail of
T-39, and profiled cirrus
that were observed by
the ER-2
4/29 X X X DC-8 profiled stratus
clouds at CART site for
radar calibration. T-39
sampled DC-8 exhaust.
4/30 X X X DC-8 studied wave cloud
and practiced finding
757 exhaust. T-39
sampled 757 exhaust.
5/2 X X ER-2 and DC-8 studied
wave cloud over Boulder.
5/3 X X X X Xe Sampling of 757 contrail
by the DC-8 and T-39.
5/4 X X X X Xe,o Sampling of the 757
contrail by the DC-8 and
T-39.
5/7 X X X X Sample persistent
contrails over Nebraska
5/8 X X X study convection, T-39
studies DC-8 exhaust.
5/10 X X X transit to Ames or
Langley
5/12 X X Persistent contrail.
5/15 X X Cirrus over water.
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Total 19 18 15 4 11
Flight
hours 110 85
*e=Egret, o=Twin otter
Many of the flights were made over the Department of Energy's Climate and Radiation Testbed (CART) site in Northern Oklahoma, where a suite of ground based remote sensing instruments was located. The DOE also operated an Egret and a Twin Otter aircraft, mostly using remote sensing instruments. The flight dates over the CART site, and those on which the Egret or Otter flew, are also noted in Table 1.
Table 2 list the targets of the various flights, as planned and as flown. Meteorological opportunities were found for most of the planned missions in the vicinity of Salina, Kansas. However, the cirrus-over-water flight could not be done from Salina, but instead was done over the Pacific Ocean using Ames Research Center as a base of operations. Although a diurnal chemistry flight was attempted, weather conditions prevented it from being done. That was the only objective for which a research flight was not completed. Most of the instruments functioned for the majority of the mission.
| Missions | Flights Proposed |
Flights Flown |
|---|---|---|
| Contrails | 3 | 6 |
| Cirrus | 2 | 7 (+1 stratus) |
| Lenticular Clouds | 2 | 2 |
| Cirrus over water | 2 | 2 |
| Near Field | 3 | 3 (757) (parts of 11) |
| Second Priority Missions: | ||
| Outflow from Convective Clouds | 2 | 2 |
| Diurnal Chemistry in Clear Skies | - | 0 |
| Clear sky aerosols | - | many |
There were a large number of interesting science results from the SUCCESS project. Although it is too early to determine if every question posed for SUCCESS was answered, it is clear that considerable progress was made.
A great deal was learned about the radiative properties of cirrus clouds and contrails. A number of multiple-aircraft flights were made, with aircraft making radiative as well as in situ measurements over the well-instrumented CART site. Several coincident flights with satellite overpasses were made. The most complete set of ice cloud particle size distributions and cloud optical properties to data were obtained, which should help resolve long-standing debates about the role of small particles in ice cloud radiative properties, and the shape of the scattering phase function for ice particles of various shapes. Numerous flights were made in which vertical profiles of cloud properties were obtained, and several flights were performed which helped to calibrate ground-based and aircraft-based remote sensing instruments.
Much data were obtained which should shed light on the formation mechanisms of cirrus clouds and contrails. Supersaturations at which ice nucleation occurs were measured which will aid in the prediction of ice formation, and contrails were observed at temperatures where existing theories did not predict their occurrence so new theories may be needed. The first extensive measurements of ice nuclei (IN), cloud condensation nuclei (CCN), and condensation nuclei (CN) concentrations as well as compositions in the upper troposphere were made. The swelling and pre-activation of aerosols providing insight into the nucleation process were observed, the scavenging of aerosols by ice crystals were observed, and data on the (surprising) composition of the aerosols in the upper troposphere over the US were collected. Much evidence was found for significant mixing between the surface and upper troposphere, and possibly on the alterations of aerosol properties which occur in convective cloud systems. Also observed was a number of interesting dynamical phenomena associated with the tropopause.
One goal was to develop and test a series of new instruments. Each of the new instruments on the DC-8 performed very well. A new suite of instruments for gas phase chemistry, aerosol chemistry and microphysics is now available to the community. In addition, numerous instrument intercomparisons were performed (e.g., 5 independent air temperature measurements, 4 independent water vapor measurements, as well as multiple CN, ice water content, IN and particle size measurements). These intercomparisons indicated not only good agreement in some cases, but revealed problems with some measurements previously thought to be reliable.
The goal of obtaining new Near Field data was clearly met and exceeded. Both gas and particle data were obtained from very close to the engine (< 50m) to far from the aircraft (>10 km) for a variety of aircraft. Data were obtained in persistent and not- persistent contrails, in exhaust which did not form a contrail, at a variety of altitudes and for fuels with a large range of sulfur contents. Unique data on concentrations of sulfur, nitrogen, and odd- hydrogen species, as well as on particles were obtained. Numerous emission indices were determined for a variety of aircraft and flight conditions.
SUbsonic aircraft Contrail & Clouds Effects Special Study (SUCCESS)
See Project/Campaign Overview.
During the SUCCESS field deployment, all three aircraft were based in Salina, Kansas. A series of flights, averaging one every other day during this period, was made mainly near the Department of Energy's Clouds and Radiation Testbed site (CART) located in Northern Oklahoma, and Southern Kansas. During this same time period an extensive set of ground based measurements were made by the DOE, which was also operating several aircraft in the area to better understand the radiative properties of the atmosphere. Additional flights were made over the Rocky Mountains, to investigate wave clouds. Flights were also made over the Gulf of Mexico to utilize an oceanic background for remote sensing measurements.
See Project/Campaign Overview.
Two data sets are currently available from the Langley DAAC.
Data were transitioned to the Langley DAAC via electronic means. Video data was transferred on VHS videotape. Data are distributed from the Langley DAAC via ftp and 4mm, 8mm and DLT tape. Video data is distributed on VHS video. The remaining data sets are archived at the SUCCESS Archive at Ames Research Center.
There is no proprietary status for the data sets currently on-line at the Langley DAAC.
There is no cost associated with this data.
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