When the first observations of a tropospheric trace gas were obtained in the 1980s, carbon monoxide enhancements from
tropical biomass burning dominated the observed features. In 2005, an active remote-sensing system to provide detailed
information on the vertical distribution of aerosols and clouds was launched, and again, one of the most imposing
features observed was the presence of emissions from tropical biomass burning. This paper presents a brief overview of
space-borne observations of the distribution of trace gases and aerosols and how tropical biomass burning, primarily in
the Southern Hemisphere, has provided an initially surprising picture of the distribution of these species and how they
have evolved from prevailing transport patterns in that hemisphere. We also show how interpretation of these
observations has improved significantly as a result of the improved capability of trajectory modeling in recent years and
how information from this capability has provided additional insight into previous measurements form satellites.
The need for high resolution spatial and temporal measurements of tropospheric ozone is discussed. Tropospheric ozone is globally increasing due to anthropogenic sources such as industrialization and biomass burning. In addition to its hazardous effects during pollution episodes, elevated levels of tropospheric ozone may have additional detrimental environmental effects due to ozone's crucial role in tropospheric chemistry and in global climate. Ground-based lidar instruments can play an important role in meeting this measurement need. We present test results for a prototype compact, minimal-cost ozone lidar. The instrument is designed to be as reliable and simple as possible but still be capable of routinely measuring ozone profiles with less than 10% relative error from the ground up into the lower stratosphere. In addition to local pollution monitoring, this lidar satisfies the basic requirements necessary for future global monitoring projects requiring multi-instrument networks, such as that proposed for the Global Tropospheric Ozone Project (GTOP). GTOP is currently being formulated by a scientific panel of the International Global Atmospheric Chemistry Project to meet its goal to better understand the processes that control the global sources, sinks, and transformation mechanisms of tropospheric ozone.
Current results from laboratory testing of an eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar measurements in the troposphere are presented. This compact prototype instrument is intended to be a prototype for operation at remote field sites and to serve as the basic unit for future monitoring projects requiring multi-instrument networks. In order for the lidar to be widely deployed, it must be fairly easy to use and maintain as well as being cost-competitive with a ground station launching ozone sondes several times a week. To achieve these goals, the system incorporates (1) an all- solid state compact OPO transmitter, (2) a highly efficient, narrow bandpass grating-based receiver, (3) dual analog and photon-counting detector channels, and (4) a PC-based data acquisition system.
KEYWORDS: Ozone, Receivers, LIDAR, Transmitters, Optical parametric oscillators, Mirrors, Analog electronics, Near field optics, Data acquisition, Camera shutters
The development of a portable, eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar (DIAL) measurements in the troposphere is presented. This compact prototype instrument is intended to operate at remote field sites and to serve as the basic unit for future monitoring projects requiring multi-instrument networks. In order for the lidar technology to be widely deployed in networks, it must be fairly easy to use and maintain as well as being cost-competitive with a ground station launching ozone sondes several times a week. The chosen laser transmitter for the system is an all-solid state tunable frequency-doubled OPO which produces 25 mJ uv pulses. Progress with alternative solid-state uv laser sources based upon an IR-pumped OPO and based upon stimulated Raman scattering in barium nitrate will be discussed. The receiver incorporates highly efficient dielectric coatings, a parabolic primary and a narrow- bandpass grating-based filter. Dual analog and photon-counting detector channels are incorporated to extend the measurement range. All data acquisition and control hardware is incorporated in an industrial PC-based system. A flexible, user-friendly graphical user interface is written in LabVIEW for data acquisition and online processing and display.
The geostationary tropospheric pollution satellite (GEO TROPSAT) mission is a new approach to measuring the critical constituents of tropospheric ozone chemistry: ozone, carbon monoxide, nitrogen dioxide, and aerosols. The GEO TROPSAT mission comprises a constellation of three instruments flying as secondary payloads on geostationary communications satellites around the world. This proposed approach can significantly reduce the cost of getting a science payload to geostationary orbit and also generates revenue for the satellite owners. The geostationary vantage point enables simultaneous high temporal and spatial resolution measurement of tropospheric trace gases, leading to greatly improved atmospheric ozone chemistry knowledge. The science data processing, conducted as a research (not operational) activity, will provide atmospheric trace gas data many times per day over the same region at better than 25 km ground footprint. The high temporal resolution identifies short time scale processes, diurnal variations, seasonal trends, and interannual variation.
Measurements from two independent satellite data sets have been used to derive the climatology of the integrated amount of ozone in the troposphere. These data have led to the finding that large amounts of ozone pollution are generated by anthropogenic activity originating from both the industrialized regions of the Northern Hemisphere, and from the southern tropical regions of Africa. To verify the existence of this ozone anomaly at low latitudes, an ozonesonde capability has been established at Ascension Island (8 degree(s)S, 15 degree(s)W), since July, 1990. According to the satellite analyses, Ascension Island is located downwind of the primary source region of this ozone pollution, which likely results from the photochemical oxidation of emissions emanating from the widespread burning of savannas and other biomass. These in situ measurements confirm the existence of large amounts of ozone in the lower atmosphere. A summary of these ozonesonde data to date is presented. In addition, some ozone profile measurements are presented from SAGE II which can be used to provide upper tropospheric ozone measurements directly in the tropical troposphere. A preliminary comparison between the satellite observations and the ozonesonde profiles in the upper troposphere and lower stratosphere also are presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.