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Geoscience and Remote Sensing Symposium, 2002. IGARSS '02. 2002 IEEE International

Date 24-28 June 2002

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  • 2002 IEEE International Geoscience and Remote Sensing Symposium [front matter]

    Page(s): 0_1 - 0_94
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  • Retrieval of subpixel fire temperature and fire area in Moderate Resolution Imaging Spectrometer

    Page(s): 3205 - 3207 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    The ability to retrieve information at subpixel spatial resolution from a satellite with more than one channel in the thermal infrared spectral range has benefited the monitoring of forest fires. With better sensors, the severity of fire and the degree of damage can be estimated by retrieving fire fraction and fire temperature using the Dozier procedure. A sensitivity analysis was also performed to estimate the uncertainty in the retrieval of fire fraction and fire temperature as a result of inaccurate determination of emissivity and background temperature. View full abstract»

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  • Author index

    Page(s): 3695 - 3710
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  • GoMEx-an experimental GIS system for the Gulf of Mexico region using SAR and additional satellite and ancillary data

    Page(s): 3343 - 3345 vol.6
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    The National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite, Data, and Information Service (NESDIS) is in the third year of the Alaska SAR Demonstration (AKDEMO), an applications project using RADARSAT-1 synthetic aperture radar (SAR) and derived products. The success of this demonstration in providing near real-time SAR data, derived products, and other ancillary data to federal and state agencies, has motivated the development of a similar experimental multi-sensor data fusion system for the Gulf of Mexico and Caribbean region called GoMEx. Unlike the AKDEMO system which focused on near-real time data, this project will begin by using archived data from diverse remote sensing sensors such as RADARSAT-1 SAR, GOES imagers, SeaWiFS, MODIS, AVHRR, scatterometers, as well as data from moored buoy measurements and numerical weather models to study issues and phenomena unique to the region. Other agencies that will contribute and use this system include the National Ocean Service (NOS), Louisiana State University, National Marine Fisheries Service and the University of Maryland. Sample applications of this system are presented including detection of algal blooms, coral reefs off of Belize, oil slicks and rigs off of Louisiana, and fishery applications. View full abstract»

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  • MODIS geolocation error analysis developments

    Page(s): 3661 - 3663 vol.6
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    The Moderate Resolution Imaging Spectroradiometer (MODIS) contains 36 bands from the visible to the thermal infrared with the nominal ground field of views of 250 m, 500 m and 1 km. This paper summarizes the changes to the MODIS Earth location algorithm and geometric parameters since the launch of MODIS on the Terra spacecraft in December 1999. Detailed analysis of residuals from a global network of ground control points reveals biases in unexpected areas of the MODIS geometric model. For instance, systematic off-nadir along-track errors are best modeled by a tilt in the mirror coordinate system. Analysis also indicates that some along-track errors are possibly caused by uncertainty in spacecraft attitude estimates. We discuss how reducing these errors enable sub-pixel geolocation accuracy goals to be achieved. View full abstract»

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  • Field campaign for quantitative remote sensing in Beijing

    Page(s): 3133 - 3135 vol.6
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    In order to evaluate and improve the remotely sensed land surface parameters' accuracy and assimilate accumulating remote sensing data with land surface models, an integrate field campaign was carried out during the winter wheat growth season in 2001. The field campaign was funded by the Chinese Special Funds for Major State Basic Research Project: Quantitative remote sensing theory and application of land surface parameters (QRSLSP). Research on scale effect and angular characteristics of remote sensing data is the most important objectivity. Three different scales of research area are responding to different spatial resolution of remote sensing sensors. The experimental database include space-borne remote sensing data, airborne remote sensing data and field observation data. Some significant research advances have been achieved based the experiment data set, while most research proposals are carrying on. View full abstract»

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  • Global map of water vapor content from ADEOS/POLDER and NASA/AERONET

    Page(s): 3218 - 3220 vol.6
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    The ADEOS/POLDER sensor provides the first opportunity to measure the atmospheric water vapor content on a global scale. A POLDER sensor, mounted on the Earth observation satellite ADEOS in 1996, is a unique sensor which can gather multi-(up to 14) directional polarization measurements of one target. Two channels of POLDER in the near infrared wavelengths are examined in this study. The first channel is in the water vapor absorption band of 0.910 μm and the second is in the gas absorption-free band of 0.865 μm. In practice, a ratio of each reflectance for these two channels is used to estimate the total column water vapor content. This algorithm is referred to as the two-channel ratio method. It is shown that the global distribution of water vapor content from the POLDER data present the typical characteristics of spatial and temporal changes. The water vapor content has high values over the tropical zone and decreases with latitude. Furthermore, the Indian monsoon is clearly demonstrated in the water vapor map. It should be noted that the water vapor content retrieved from the POLDER data has been validated with AERONET measurements. View full abstract»

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  • Temporal variability of land surface and land cover classification using statistics of temporal variability in Korean Peninsula

    Page(s): 3288 - 3289 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (330 KB) |  | HTML iconHTML  

    This study analyzed time variability of the normalized difference vegetation index (NDVI), the leaf area index (LAI) and surface temperature(T) estimated using AVHRR data observed from 1996 and 2000 over Korean Peninsula. In this study, the observed data series, which include many missing/bad values, were reconstructed as a complete image series with two-day interval using dynamic compositing. View full abstract»

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  • The MANTRA campaigns - studying the stratosphere from balloons

    Page(s): 3136 - 3138 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (283 KB) |  | HTML iconHTML  

    The MANTRA (Middle Atmosphere Nitrogen Trend Assessment) series of high-altitude balloon flights is being undertaken to investigate changes in the concentrations of mid-latitude stratospheric ozone, and of nitrogen and chlorine compounds that play a role in ozone chemistry. Two balloons have been launched from Vanscoy, Saskatchewan, the first in August 1998 and the second in August 2000. Each carried a payload of instruments to measure vertical concentration profiles of stratospheric trace gases, and made observations from a float altitude of about 35 km for one day. Several of these instruments were flown 15-20 years ago and thus provide a link to historical data predating the onset of mid-latitude ozone loss. We are now preparing for two additional MANTRA flights, in 2002 and 2003. These new flights will extend the number of trace gases measured, and will include most of the previously flown instruments along with several new ones. This will enable a comparison of measurements of the same gases made by different instruments for the investigation of previously observed discrepancies and an assessment of the instruments' performance. The measurements will also be used to quantify changes in the chemical balance of the stratosphere, with a focus on changes in nitrogen oxides. In addition, the resulting data will be used for validation of several satellite instruments. View full abstract»

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  • COSMO-SkyMed SAR processing parallel implementation

    Page(s): 3165 - 3166 vol.6
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    COSMO-SkyMed constellation will acquire data from its four SAR satellites in several image modes, and will generate focused data products. As images will be acquired at fine geometric resolution and will cover medium sized swath, the SAR processing involved will result well suited to parallel programming implementation. View full abstract»

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  • Scattering from wet snow by applying strong fluctuation theory

    Page(s): 3539 - 3541 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB) |  | HTML iconHTML  

    In this study, the strong fluctuation theory is applied to calculate the scattering from a half space of wet snow. The first and second moments of the fields are calculated, respectively, by using the bilocal and the distorted Born approximations, and the low frequency limit is taken. The singularity of the dyadic Green's function is taken into account. The effective permittivity of wet snow is calculated by the two-phase model with non-symmetrical inclusions. In the two-phase model, wet snow is assumed to consist of dry snow (host) and liquid water (inclusions). Numerical results for the backscattering coefficients of wet snow are illustrated for random media with isotropic and anisotropic correlation functions. The three-phase strong fluctuation theory model with symmetrical inclusions is also presented for theoretical comparison. In the three-phase model, wet snow is assumed to consist of air (host), ice (inclusions) and water (inclusions) and the shape of the inclusions are spherical. View full abstract»

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  • Recent MATR retrieval results over Los Angeles

    Page(s): 3186 - 3188 vol.6
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    The MOPITT (Measurements Of Pollution In The Troposphere) Airborne Test Radiometer (MATR) uses gas filter correlation radiometry to measure tropospheric carbon monoxide (CO) using one length-modulated correlation cell and one pressure-modulated correlation cell. The aircraft that carries MATR usually also carries an in situ sampling system. This paper presents an overview of the MATR instrument and its validation (using in situ data), and then presents results from a flight over Los Angeles. View full abstract»

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  • A fusion-based segmentation algorithm for high-resolution panchromatic aerial photography

    Page(s): 3396 - 3398 vol.6
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    We propose a mixed segmentation algorithm based on both gray level information and a texture parameter. The definitive k-class image is obtained by means of a simple fusion scheme. Our algorithm considers the following steps: (a) obtainment of an n-class image by means of an algorithm based exclusively on spectral properties, (b) obtainment of a texture image, which may be generated by Markov random fields (MRF) modeling or by means of the co-occurrence matrix. (c) From the n-class image of the first step we obtain a mask for each class; based on these masks we analyze the variation degree of the texture parameter: if the variation degree is greater than a defined threshold the class is fissioned into 2 classes, otherwise it remains the same. (d) The definitive class image is obtained by fusing the different sub-images created in the previous step. Results show that considering complementary information in the segmentation process results in a better discrimination among classes, while the main edges of the scene are clearly defined. View full abstract»

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  • Experimental results of synthetic aperture microwave radiometer

    Page(s): 3635 - 3637 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (674 KB) |  | HTML iconHTML  

    Introduces briefly the principles of the interferometric synthetic aperture, a system design of a C-band microwave interferometric synthetic aperture radiometer and its experimental results. This system has a 6-element thinned array with 11 analog complex correlators to obtain the 11 visibility functions, which result in 22 digitally synthesized spatial resolution cells. The synthetic aperture radiometer has a spatial resolution as high as 1/22 of that corresponding to a one-antenna element. The synthetic radiometer has a real aperture resolution cell in the along-track direction and has 22 synthetic aperture resolution cells in the cross-track direction. Finally, the results of imaging experiments are given. View full abstract»

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  • A fast source separation algorithm for hyperspectral image processing

    Page(s): 3516 - 3518 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (389 KB) |  | HTML iconHTML  

    This paper describes a new algorithm for feature extraction in hyperspectral images based on independent component analysis (ICA). The improvement introduced aims at reducing the computation times without decreasing the accuracy. Instead of using the entire image, we perform ICA processing on a subset of representative pixel vectors obtained through spectral screening. Spectral screening is a technique that measures the similarity between pixel vectors by calculating the angle between them. In multispectral/hyperspectral imagery, the independent components can be associated with features present in the image. ICA projects them in different image frames. The features are separated using an algorithm involving gradient descent minimization of the mutual information between frames. The effectiveness of the proposed algorithm (SSICA) has been tested by performing target detection on data from the Hyperspectral Digital Imagery Collection Experiment (HYDICE). Small targets present in the image are separated from the background in different frames and the information pertaining to them is concentrated in these frames. Further selection using kurtosis, skewness and histogram thresholding lead to automated detection of the targets allowing a quantitative assessment of the results. When compared with a target detection ICA algorithm previously introduced by the authors, SSICA achieves similar accuracy, and, at the same time, considerable speedup is obtained. View full abstract»

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  • A new maximum likelihood generalized gamma CFAR detector

    Page(s): 3399 - 3401 vol.6
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    The Generalized Gamma Model has as special cases the Rayleigh, Weibull and Lognormal models. It also closely approximates the K-pdf model. Radar Clutter is often approximated in one of these forms. It is therefore quite useful to develop CFAR (Constant False Alarm Rate) detectors that perform well under this clutter model. In this paper, a Maximum Likelihood Generalized Gamma (MLGG) CFAR detector has been developed. This MLGG detector uses the Maximum Likelihood Equations, both locally and globally, in order to estimate the parameters of the Generalized Gamma clutter. These estimated parameters are then used to estimate the local mean of the detector. The mean of the local CFAR window is then taken as the first moment of the Generalized Gamma distribution evaluated with the estimated parameters. In the examples it is shown that in homogeneous Generalized Gamma clutter, with point targets, the MLGG detector outperforms our standard test detectors, Cell Averager, Ordered Statistic and Optimized Weibull. View full abstract»

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  • Monitoring of forest fire damage by using JERS-1 InSAR

    Page(s): 3290 - 3292 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (610 KB) |  | HTML iconHTML  

    The authors investigated on the applicability of interferometric SAR (InSAR) for monitoring forest fire damage. We attempted to use the coherence information obtained through interferometric SAR (InSAR) to detect and monitor damaged areas by forest fire. The test site is the forest around Tamano City in Okayama Prefecture, where a relatively big forest fire occurred in August, 1994, and a total area of 359 ha was burnt. We used several interferometric data pairs by JERS-1 SAR acquired before and after the forest fire. The multilook intensity images and the coherence images were created in the test site and both of intensity and coherence changes due to the fire in damaged forest areas were extracted and they were compared with those in non-damaged forest areas. The result indicated that intensity decreased slightly after the fire, however, the change was not big enough to interpret and extract damaged forest areas clearly. On the other hand, coherence increased significantly in damaged areas after the fire and it was much easier to interpret and extract damaged areas compared with intensity. The experimental result in this study supports that InSAR is effective for detecting and monitoring land cover changes by a forest fire as well as deforestation, for which InSAR has been already verified to use effectively. View full abstract»

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  • Retrieval of surface skin temperature from MOPITT measurements: validation and impacts to the retrievals of tropospheric carbon monoxide profiles

    Page(s): 3177 - 3179 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (362 KB) |  | HTML iconHTML  

    The Measurements Of Pollution In The Troposphere (MOPITT) instrument is designed to measure the spatial and temporal variation of the carbon monoxide (CO) profile and total column amount in the troposphere from space. MOPITT channels are sensitive to both thermal emission from the surface and target gas absorption and emission. Surface temperature and emissivity are retrieved simultaneously with the CO profile. To obtain the desired precision for the retrieved CO profiles, it is important to retrieve the surface skin temperature accurately and understand the effects of any errors in retrieved skin temperature on retrieved CO. To demonstrate the impacts of surface skin temperature on the retrieval of the tropospheric CO profile, a simulation study is performed. The collocated Moderate Resolution Imaging Spectroradiometer (MODIS) surface temperatures are used to validate the accuracy of the retrieved MOPITT surface temperatures. View full abstract»

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  • Assessing cloud contamination effects on K-means unsupervised classifications of Landsat data

    Page(s): 3387 - 3389 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (266 KB) |  | HTML iconHTML  

    Satellite data, such as obtained by Landsat 5 or 7 sensors, can be effectively used for large-area land cover classifications. Given that approximately 50% of the Earth is covered in cloud at any time, one of the significant challenges in creating repeatable and robust classifications is to understand and appropriately address cloud contamination in Landsat images. The scope of many of the large area mapping projects and the associated large volumes of data to be processed suggest that unsupervised classifications and automated processes may be necessary to obtain timely results. An experiment was developed to investigate the effect of cloud contamination on unsupervised classifications. It was determined that when a small number of classes are used cloud effects in the cloud-free portion of the scene can often be managed by allocating the majority of clusters to clouds. When a large number of classes are required, clouds significantly skew the non-cloud cluster characteristics. View full abstract»

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  • Experimental investigations of amplitude and phase progression fluctuations on microwave line-of-sight links

    Page(s): 3559 - 3560 vol.6
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    Experimental investigations of amplitude and phase progression fluctuations on microwave line-of-sight links are presented. The transmitter unit is represented as a receiver-transmitter device operating for the same antenna. Here the transmitter signal is the heterodyne signal for the receiver. The low frequency channel is used to get in-phase oscillations in both parts of microwave link. The initial phase of low frequency oscillations is transferred on microwave. View full abstract»

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  • Diurnal variation of direct and diffuse radiation and its impact on surface albedo

    Page(s): 3224 - 3226 vol.6
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    A method for calculating the diurnal distribution of direct and diffuse solar radiation was developed. Based on this method, we analysed the changing patterns of the two radiation components under different weather conditions. The results were then used to investigate the effect of underlying snow of a forest on the surface albedo. It shows that the albedo contribution from the underlying snow is stable on overcast days when the radiation is dominated by the diffuse component. However, on clear days when the radiation is dominated by the direct component, the diurnal change of albedo contributed from the snow is significant and it exhibits a "w" shape. It was also found that under any weather conditions, the vegetation masking effect is very significant. As a result, the albedo contribution from the underlying snow in the high latitude is much less than that obtained by the fractional average method commonly used in land surface schemes of climate models. View full abstract»

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  • Japan image database for utilization

    Page(s): 3139 - 3141 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB) |  | HTML iconHTML  

    Using the NOAA-HRPT data received at Tohoku University, a satellite image database for researchers is called the Tohoku Image Database (TIDAS). TIDAS is open for the public, and can be accessed via the Internet. The albedo and brightness temperatures processed from the AVHRR channel 2 and channel 4 are geocoded. This database starts from April 1990. The area is Tohoku on the east side of Japan. From 1996, the database includes the west side of Japan called the Japan Image Database (JAIDAS) to the present. The image data are 1024×1024 pixel for every channel data (Ch1 - Ch5) as the original. And also GIF files are presented as 1/4 size images in the catalog. The output images from the database are on the increase. In 1994 there were 7,834, in 1996 42,776, in 1998 74,241 and in 2000 219,740 images. We counted over 520,000 in only a half period of 2001. The results mean requests for environmental studies and education. We developed JAIDAS into the Tohoku University NOAA Image Database for more contributions to Earth environmental studies. View full abstract»

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  • Full polarimetric emissivity of vegetation-covered soils: vegetation structure effects

    Page(s): 3542 - 3544 vol.6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    In May 1999 the SMOS Earth Explorer Opportunity mission was selected by ESA to provide global soil moisture and sea salinity maps using the MIRAS L-band aperture synthesis interferometric radiometer. At this frequency there is a high dynamic range of the soil moisture signature and surface roughness effects are small, as well as vegetation effects. However, they cannot be neglected at large observation angles or if the vegetation cover is thick and/or dense. In this paper we have carried out a series of simulations to investigate the effect of the soil moisture content and the vegetation density, the influence of the vegetation structure (number, sizes and orientation of branches and leaves) and the influence of each component (trunk, branches, and leaves) on the four Stokes elements J, Th, U and V. View full abstract»

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  • Test results from a 1319-nm laser radar with RF pulse compression

    Page(s): 3588 - 3590 vol.6
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    We report the results of a three-year, NASA-funded project at The University of Kansas Radar Systems and Remote Sensing Laboratory on the development of a laser radar that uses RF pulse compression to significantly improve system performance. Receiver sensitivities of less than -90 dBm have been demonstrated by applying heterodyne optical downconversion and RF pulse compression. With the improved sensitivity, the required transmit power is significantly reduced. This system approach also permits multi-kilohertz pulse-repetition frequencies that enable spatially dense range measurements. Compared to lidars like GLAS and MOLA, this sensor requires a lower peak transmit power while providing orders of magnitude more measurements per second. In the receiver design, we have evaluated two detection schemes: envelope detection and direct downconversion. Envelope detection provides the benefit of discarding the effects of optical phase variations on the detected signal consequently avoiding many temporal correlation issues, however it is less efficient in terms of the resulting signal-to-noise ratio (SNR). Direct downconversion to baseband is more SNR efficient, however the baseband signal contains the effects optical phase variations, which include laser phase noise, effects of atmospheric turbulence, and frequency shifting due to Doppler effects. We have demonstrated the feasibility of using a linear array of optical fibers in the telescope's focal plane to launch and receive the optical signals. Using separate fibers for transmit and receive while sharing telescope optics, we have achieved the required transmitter-receiver isolation of a bistatic system without the accompanying alignment difficulties. With our breadboard system ranging measurements from both man-made and natural extended targets have been made and the results are presented. These results support the feasibility of a satellite-based altimeter (600 km altitude), capable of making more than 4000 range measurements per second with 10 cm accuracy using less than 10 W peak transmit power. While the present breadboard operates at 1319 nm, the overall concept is wavelength independent. Benefits of this development may include increased system reliability, reduced power requirements, smaller sensor mass a- nd volume, improved eye-safety, and lower probability of signal detection. View full abstract»

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  • Relative enhancements of ozone, carbon monoxide, nitrogen dioxide, and aerosols at the Earth's surface during Asian dust episodes in spring

    Page(s): 3267 - 3269 vol.6
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    Time series of ozone, CO, and NO2 surface mixing ratios and of aerosol density have been derived using ultraviolet photometry, infrared absorption spectrometry, gas filter correlation radiometry, and beta-ray absorption, respectively, at Busan, Korea (35.23°N, 129.07°E) since 1992. Enhancements of ozone above 100 ppbv were observed during an Asian dust event on 1 May 1999. A secondary ozone maximum observed at the surface was expected as the result of invasion of air from the free troposphere due to the jet stream. Sudden increases in CO, NO2 and aerosols were caused by the combination of the deepening cut-off low connecting with a surface cyclone, and the slow-moving surface anticyclone located to the south of the upper trough over Korea. The elevated mixing ratios of these gases and aerosols were the result of chemical reactions and stratosphere-troposphere exchange due to tropopause folding in the rear of the jet streak under these weather conditions. In the presence of sufficiently high concentrations of NOx, the enhancement of ozone was due to the catalytic reaction of CO that originates in fossil fuel and biomass burning emissions from China, together with ozone precursors such as VOCs that occur in Busan, Korea. In addition, transport of ozone was determined not only by the invasion of stratospheric ozone followed by tropopause folding of the deep cut-off low associated with the movement of total ozone, but also by long-range horizontal transport from China and from an anticyclone located to the south of Korea. The relative importance of chemical reactions and transport of these gases in the urban area was analyzed using an urban airshed model (UAM) that included biogenic and anthropogenic emissions of VOCs and other gases. It showed that we could estimate the net flux of the ozone mixing ratio due to both long-range advection and free troposphere-boundary layer exchange in connection with stratosphere-troposphere exchange during Asian dust events in springtime. View full abstract»

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