Vincent G. Brackett

Langley Research Center

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E. V. Browell

Langley Research Center

S. A. Kooi

Science Systems and Applications (United States)

M. Clayton

Langley Research Center

William B. Grant

Sunlight Nutrition and Health Research Center

R. A. Ferrare

Langley Research Center

Syed Ismail

National Institute of Technology Warangal

C. F. Butler

Langley Research Center

Marta A. Fenn

Langley Research Center

Jack Fishman

UCLouvain Saint-Louis Brussels

M. J. Mahoney

SUNY College of Environmental Science and Forestry

Cooperative Institutions

Langley Research Center

NSF National Center for Atmospheric Research

Goddard Space Flight Center

University of Colorado Boulder

Ames Research Center

National Oceanic and Atmospheric Administration

University of California, Irvine

Georgia Institute of Technology

National Aeronautics and Space Administration

Science Systems and Applications (United States)

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Large‐scale ozone and aerosol distributions, air mass characteristics, and ozone fluxes over the western Pacific Ocean in late winter/early spring

Journal of Geophysical Research Atmospheres (2003)

E. V. Browell Marta A. Fenn Carolyn F. Butler William B. Grant Vincent G. Brackett

Large‐scale measurements of ozone (O 3 ) and aerosol distributions were made from the NASA DC‐8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE‐P) field experiment conducted in February–April 2001. Remote measurements were made with an airborne lidar to provide O 3 and multiple‐wavelength aerosol backscatter profiles from near the surface to above the tropopause along the flight track. In situ measurements of O 3 , aerosols, and a wide range of trace gases were made onboard the DC‐8. Five‐day backward trajectories were used in conjunction with the O 3 and aerosol distributions on each flight to indicate the possible origin of observed air masses, such as from biomass burning regions, continental pollution, desert regions, and oceanic regions. Average latitudinal O 3 and aerosol scattering ratio distributions were derived from all flights west of 150°E, and these distributions showed the average latitude and altitude dependence of different dynamical and chemical processes in determining the atmospheric composition over the western Pacific. TRACE‐P (TP) showed an increase in the average latitudinal distributions of both O 3 and aerosols compared to PEM‐West B (PWB), which was conducted in February–March 1994. O 3 , aerosol, and potential vorticity levels were used to identify nine air mass types and quantify their frequency of occurrence as a function of altitude. This paper discusses the characteristics of the different air mass types encountered during TP and compares them to PWB. These results confirmed that most of the O 3 increase in TP was due to photochemistry. The average latitudinal eastward O 3 flux in the western Pacific during TP was found to peak near 32°N with a total average O 3 flux between 14 and 46°N of 5.2 Tg/day. The eastward total CO flux was calculated to be 2.2 Tg‐C/day with ∼6% estimated from Asia. The Asian flux of CO 2 and CH 4 was estimated at 4.9 and 0.06 Tg‐C/day.

Trace gas

Tropopause

10.1029/2002jd003290

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Citations (52)

LASE measurements of water vapor, aerosols, and clouds during SOLVE

R. A. Ferrare Syed Ismail E. V. Browell John D. Barrick G. W. Sachse

Airborne water vapor lidar measurements are used to observe moisture variability in tropopause folds, characterize ice supersaturation regions, compare satellite and in situ water vapor measurements, and reveal wave structure in aerosol and cloud distributions.

Supersaturation

Tropopause

10.1364/ors.2001.omb4

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Citations (2)

Characterization of Upper-Troposphere Water Vapor Measurements during AFWEX Using LASE

Journal of Atmospheric and Oceanic Technology (2004)

R. A. Ferrare E. V. Browell Syed Ismail S. A. Kooi L. H. Brasseur

Abstract Water vapor mass mixing ratio profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the Atmospheric Radiation Measurement (ARM)–First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX) are used as a reference to characterize upper-troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors over the Department of Energy (DOE) ARM Southern Great Plains (SGP) site in northern Oklahoma. LASE was deployed from the NASA DC-8 aircraft and measured water vapor over the ARM SGP Central Facility (CF) site during seven flights between 27 November and 10 December 2000. Initially, the DOE ARM SGP Cloud and Radiation Testbed (CART) Raman lidar (CARL) UTWV profiles were about 5%–7% wetter than LASE in the upper troposphere, and the Vaisala RS80-H radiosonde profiles were about 10% drier than LASE between 8 and 12 km. Scaling the Vaisala water vapor profiles to match the precipitable water vapor (PWV) measured by the ARM SGP microwave radiometer (MWR) did not change these results significantly. By accounting for an overlap correction of the CARL water vapor profiles and by employing schemes designed to correct the Vaisala RS80-H calibration method and account for the time response of the Vaisala RS80-H water vapor sensor, the average differences between the CARL and Vaisala radiosonde upper-troposphere water vapor profiles are reduced to about 5%, which is within the ARM goal of mean differences of less than 10%. The LASE and DC-8 in situ diode laser hygrometer (DLH) UTWV measurements generally agreed to within about 3%–4%. The DC-8 in situ frost point cryogenic hygrometer and Snow White chilled-mirror measurements were drier than the LASE, Raman lidars, and corrected Vaisala RS80H measurements by about 10%–25% and 10%–15%, respectively. Sippican (formerly VIZ Manufacturing) carbon hygristor radiosondes exhibited large variabilities and poor agreement with the other measurements. PWV derived from the LASE profiles agreed to within about 3% on average with PWV derived from the ARM SGP microwave radiometer. The agreement between the LASE and MWR PWV and the LASE and CARL UTWV measurements supports the hypotheses that MWR measurements of the 22-GHz water vapor line can accurately constrain the total water vapor amount and that the CART Raman lidar, when calibrated using the MWR PWV, can provide an accurate, stable reference for characterizing upper-troposphere water vapor.

Microwave radiometer

Mixing ratio

10.1175/jtech-1652.1

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Citations (65)

Tropospheric ozone derived from TOMS/SBUV measurements during TRACE A

Journal of Geophysical Research Atmospheres (1996)

Jack Fishman Vincent G. Brackett E. V. Browell William B. Grant

The use of data from Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter Ultraviolet (SBUV) measurements to develop daily maps of the amount of ozone in the troposphere during Transport and Atmospheric chemistry Near the Equator‐Atlantic (TRACE A) is presented. By comparing these maps with available ozone measurements from sensors aboard the NASA DC‐8, we show that the agreement between the satellite‐derived measurements and the other data is generally very good. The TOMS/SBUV technique successfully captures large‐scale gradients and the derived integrated tropospheric ozone amount is generally within 10–15% of the observed amounts. The largest discrepancy between the two data sets occurs when copious amounts of lower‐tropospheric (1–6 km) aerosols (from intense widespread biomass burning) are present. The amount of ozone found over the TRACE A region for the September–October 1992 period agrees well with the climatological values published previously using TOMS and Stratospheric Aerosol and Gas Experiment (SAGE) measurements and with ozonesonde measurements from several tropical sites established as part of TRACE A. The satellite‐derived ozone maximum observed during TRACE A is ∼1000 km north of the previously published climatological data and it is not obvious whether or not this northward shift is due to normal interannual variability, or if it is a result of systematic data processing differences between the SAGE and the SBUV data sets.

Tropospheric ozone

Trace gas

10.1029/95jd03576

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Citations (103)

The climatological distribution of tropospheric ozone derived from satellite measurements using version 7 Total Ozone Mapping Spectrometer and Stratospheric Aerosol and Gas Experiment data sets

Journal of Geophysical Research Atmospheres (1997)

Jack Fishman Vincent G. Brackett

The climatological distribution of tropospheric ozone derived from satellite observations has been updated using the reprocessed version 7 Total Ozone Mapping Spectrometer (TOMS) gridded data. The use of version 7 of the archive has not changed any of the climatological features first identified using earlier archived versions of the TOMS data. In general, however, the absolute values of the amount of ozone in the troposphere are decreased by ∼5 Dobson units (DU). In areas of persistent marine stratus clouds, the climatological values are decreased by an additional 2–3 DU.

Tropospheric ozone

10.1029/97jd01373

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Citations (78)

Characterization of upper troposphere water vapor measurements during AFWEX using LASE.

R. A. Ferrare E. V. Browell Ismayadi Ismail S. A. Kooi L. H. Brasseur

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere (UT) water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. They show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived from the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UT water vapor measurements.

Microwave radiometer

Hygrometer

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Citations (1)

Comparison of the TOMS/SBUV tropospheric ozone residual (TOR) with the TOMS/SAGE TOR and low cloud frequencies

Fred M. Vukovich Vincent G. Brackett J. Fishman Joseph E. Sickles

The 5-year (1985-1989) mean TOMS/SBUV tropospheric ozone residual (TOR) was compared with the 5-year mean TOMS/SAGE TOR. Many of the temporal and spatial features in the TOMS/SBUV TOR were similar to those found in the TOMS/SAGE TOR, suggesting a certain of consistency in the two data sets; however, significant differences were also noted. Some of these differences appear to be the result of spatial resolution differences between the TOMS/SBUV and TOMS/SAGE TOR data. Some, however, could not simply be explained by the spatial resolution differences. The comparisons between the 5-year (1985-1989) mean low-cloud frequency data with the TOMS/SBUV data showed that in some cases centers of persistent low clouds coincided with high ozone centers and in some case they did not.

10.1109/igarss.1998.702298

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Observations of reduced ozone concentrations in the tropical stratosphere after the eruption of Mt. Pinatubo

Geophysical Research Letters (1992)

William B. Grant J. Fishman E. V. Browell Vincent G. Brackett D. Nganga

The eruption of Mt. Pinatubo (15°N, 122°E) on June 15 and 16, 1991, placed a large amount of SO 2 and crustal material in the stratosphere. Based on measurements of decreases of stratospheric ozone after previous volcanic eruptions, it was expected that the aerosols deposited into the stratosphere (both directly and as a result of SO 2 conversion into particulate sulfate) by this eruption would give rise to significant ozone depletions. To check for such an effect, ozone profiles obtained from ECC sondes before and after the eruption at Brazzaville, Congo (4°S, 15°E), and Ascension Island (8°S, 14°W), are examined. Aerosol profiles determined from a lidar system in the western Pacific (4°–6°N, 125°E) show that most of the material injected into the stratosphere is located between 18 and 28 km with highest amounts at 24–25 km. For the period 3–6 months after the eruption, decreases in ozone are found at 16 to 29 km, with peak decreases as large as 20% found at 24 km. Integrated between 16 and 28 km, a decrease of 13–20 Dobson units is observed when the ozonesonde data after the Pinatubo eruption are compared with those prior to the eruption. The altitude at which the most pronounced ozone decrease is found strongly correlates with peak aerosol loading determined by the lidar. In addition, a small increase in ozone density is found above about 28 km. Mechanisms that might explain the results such as heterogeneous chemistry, radiative effects, and dynamics are discussed.

Vulcanian eruption

Sulfate aerosol

10.1029/92gl01153

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Citations (84)

Modeling of thermal lensing in side and end-pumped finite solid-state laser rods. M.S. Thesis

Vincent G. Brackett

Rod

Solid-state laser

Source

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Distribution of tropospheric ozone at Brazzaville, Congo, determined from ozonesonde measurements

Journal of Geophysical Research Atmospheres (1992)

B. Cros D. Nganga Alexis Minga Jack Fishman Vincent G. Brackett

An analysis of 33 ozonesonde launches in Brazzaville, Congo (4°S, 15°E), between June 1990 and May 1991 is presented. The data indicate highest tropospheric amounts between June and early October, coincident with the dry season and with the presence of enhanced widespread biomass burning. The seasonal cycle of ozone derived from the ozonesonde measurements is in good agreement with the climatological seasonal cycle inferred from the use of satellite data and both seasonal cycles peak in September. Averaged throughout the year, the integrated amount of ozone derived from the ozonesondes is 44 Dobson units (DU) and is 39 DU using the satellite data. Within the troposphere the highest partial pressures are generally found at pressure levels near 700 mbar (∼3 km). Using simultaneous ozonesonde data from Ascension Island (8°S, 15°W), examples are presented illustrating that differences in the troposphere are primarily responsible for the observed spatial gradients of total ozone observed by TOMS. Calculation of correlation coefficients suggests that total ozone measurements may be a better indicator of the amount of ozone in the troposphere than are surface measurements.

Tropospheric ozone

Seasonality

10.1029/92jd01219

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Citations (53)