Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494151
D. Flittner
Profiles of light scattered from the limb of the terrestrial atmosphere can provide information upon the vertical structure of optically thin aerosol layers. Such data can also be used to determine the upper altitude of thicker layers (/spl tau/>0.01). Multi-wavelength measurements can help determine relative size distribution, but only with assumptions concerning the particle index of refraction and shape. Measurements of polarization can help to narrow the range of possible optical constants and shapes, but the small range of scatterings angles limits the degree of useful information. Despite these limitations, limb scatter observations can be quite useful for stratospheric aerosol research and examining the injection of aerosols into the upper troposphere and lower stratosphere. Presented is an algorithm for the estimation of the aerosol extinction profile from 10-30 km using limb scatter radiance profiles. Data is presented from the 1 am channel of the Limb Ozone Retrieval Experiment (LORE) flown on-board STS107 (Columbia). Comparisons are made with aerosol extinction profiles measured by the Stratospheric Aerosol and Gas Experiment (SAGE) II using the solar occultation method. On average the difference for the LORE data is less than 20% with a variation of 40%. Additional results are presented for multi-wavelength Limb scatter observations made by SAGE III. Analysis of the retrievals shows altitude registration and stray light to be the major error factors.
{"title":"What can limb scatter tell us about aerosols?","authors":"D. Flittner","doi":"10.1109/AERSOL.2005.1494151","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494151","url":null,"abstract":"Profiles of light scattered from the limb of the terrestrial atmosphere can provide information upon the vertical structure of optically thin aerosol layers. Such data can also be used to determine the upper altitude of thicker layers (/spl tau/>0.01). Multi-wavelength measurements can help determine relative size distribution, but only with assumptions concerning the particle index of refraction and shape. Measurements of polarization can help to narrow the range of possible optical constants and shapes, but the small range of scatterings angles limits the degree of useful information. Despite these limitations, limb scatter observations can be quite useful for stratospheric aerosol research and examining the injection of aerosols into the upper troposphere and lower stratosphere. Presented is an algorithm for the estimation of the aerosol extinction profile from 10-30 km using limb scatter radiance profiles. Data is presented from the 1 am channel of the Limb Ozone Retrieval Experiment (LORE) flown on-board STS107 (Columbia). Comparisons are made with aerosol extinction profiles measured by the Stratospheric Aerosol and Gas Experiment (SAGE) II using the solar occultation method. On average the difference for the LORE data is less than 20% with a variation of 40%. Additional results are presented for multi-wavelength Limb scatter observations made by SAGE III. Analysis of the retrievals shows altitude registration and stray light to be the major error factors.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115349172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494142
J. Spinhirne, E. Welton, J. Campbell, T. Berkoff
The original lidars were incoherent elastic backscatter systems, and one of the original applications for such systems was profiling the vertical distribution of aerosol. In the beginning there was significant limitation in both the practicality of the lidar hardware and in using data for aerosol retrievals of significant parameters such as the aerosol extinction and backscatter cross section. The paper reviews the use of lidars for remote sensing of atmospheric aerosols.
{"title":"Monitoring aerosol distribution from ground based elastic scattering lidar: a review","authors":"J. Spinhirne, E. Welton, J. Campbell, T. Berkoff","doi":"10.1109/AERSOL.2005.1494142","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494142","url":null,"abstract":"The original lidars were incoherent elastic backscatter systems, and one of the original applications for such systems was profiling the vertical distribution of aerosol. In the beginning there was significant limitation in both the practicality of the lidar hardware and in using data for aerosol retrievals of significant parameters such as the aerosol extinction and backscatter cross section. The paper reviews the use of lidars for remote sensing of atmospheric aerosols.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126666626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494140
J. Spinhirne, S. Palm, D. Hlavka, W. Hart, E. Welton
The Geoscience Laser Altimeter System (GLAS) launched in 2003 has provided the first global aerosol profiling from space. GLAS is a two wavelength nadir viewing instrument. The measurement requirement to profile all radiatively significant aerosol layers has been exceeded. Data processing algorithms have provided aerosol scattering cross section profiles, boundary detection and height for all aerosol layers, aerosol optical depth and extinction cross section for data from 2003. The data products are openly available to the global science community.
{"title":"Global aerosol distribution from the GLAS polar orbiting lidar instrument","authors":"J. Spinhirne, S. Palm, D. Hlavka, W. Hart, E. Welton","doi":"10.1109/AERSOL.2005.1494140","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494140","url":null,"abstract":"The Geoscience Laser Altimeter System (GLAS) launched in 2003 has provided the first global aerosol profiling from space. GLAS is a two wavelength nadir viewing instrument. The measurement requirement to profile all radiatively significant aerosol layers has been exceeded. Data processing algorithms have provided aerosol scattering cross section profiles, boundary detection and height for all aerosol layers, aerosol optical depth and extinction cross section for data from 2003. The data products are openly available to the global science community.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"517 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133193285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494147
X. Wang, J. Reagan, C. Cattrall, K. Thome
Aerosol retrievals at 532 nm for the current GLAS and upcoming CALIPSO satellite lidar missions employ/will employ a table look-up approach to select climatologically based S/sub a/ model values for these retrievals when alternate, less uncertain methods for either defining S/sub a/ (the aerosol extinction-to-backscatter ratio, or aerosol lidar ratio) or providing the needed auxiliary information are unavailable. Reagan et al. (2004, 2005) addressed a revised table look-up approach that incorporated two notable revisions for improved S/sub a/ selection, which, as a consequence, enable more bounded aerosol retrievals. One is a refined, more bounded set of S/sub a/ values, both for 532 nm and 1064 nm, representative of a definitive set of aerosol types/models determined from an extensive analysis of the AERONET database. The other is an accompanying set of key spectral ratio parameters (i.e., dual wavelength, 532 nm to 1064 nm, ratios of backscatter, extinction and S/sub a/) also derived from the AERONET data which offer additional ways to bound the lidar aerosol retrievals. Thus, aerosol retrievals can be obtained subject to the constraints that the lidar data yield retrievals with spectral ratio parameters consistent with a given aerosol model (or models), to confirm the model choice and better bound the retrievals. This paper presents the simulation results made by assuming different models in support of the two-wavelength lidar constrained ratio aerosol model-fit (CRAM) retrieval approach. In addition, a performance function and multiple scattering corrections based on LITE signals are also investigated.
{"title":"Spaceborne lidar aerosol retrieval approaches based on improved aerosol model constraints","authors":"X. Wang, J. Reagan, C. Cattrall, K. Thome","doi":"10.1109/AERSOL.2005.1494147","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494147","url":null,"abstract":"Aerosol retrievals at 532 nm for the current GLAS and upcoming CALIPSO satellite lidar missions employ/will employ a table look-up approach to select climatologically based S/sub a/ model values for these retrievals when alternate, less uncertain methods for either defining S/sub a/ (the aerosol extinction-to-backscatter ratio, or aerosol lidar ratio) or providing the needed auxiliary information are unavailable. Reagan et al. (2004, 2005) addressed a revised table look-up approach that incorporated two notable revisions for improved S/sub a/ selection, which, as a consequence, enable more bounded aerosol retrievals. One is a refined, more bounded set of S/sub a/ values, both for 532 nm and 1064 nm, representative of a definitive set of aerosol types/models determined from an extensive analysis of the AERONET database. The other is an accompanying set of key spectral ratio parameters (i.e., dual wavelength, 532 nm to 1064 nm, ratios of backscatter, extinction and S/sub a/) also derived from the AERONET data which offer additional ways to bound the lidar aerosol retrievals. Thus, aerosol retrievals can be obtained subject to the constraints that the lidar data yield retrievals with spectral ratio parameters consistent with a given aerosol model (or models), to confirm the model choice and better bound the retrievals. This paper presents the simulation results made by assuming different models in support of the two-wavelength lidar constrained ratio aerosol model-fit (CRAM) retrieval approach. In addition, a performance function and multiple scattering corrections based on LITE signals are also investigated.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132002811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494149
S. Jones, F. Iannarilli, P. Kebabian, J. Conant
Aerodyne Research has developed and built a snap-shot imaging spectropolarimeter for aerosol retrievals, based on our patented polarimetric spectral intensity modulation (PSIM) technique. The resulting sensor, the Hyperspectral Polarimeter for Aerosol Retrievals (HySPAR), is capable of capturing, in a single snapshot, a full elliptical Stokes spectrum over 450-900 nm and over a 120 degree field of view. The single beam, single snapshot optical design possesses inherent spectral and polarimetric channel coregistration. HySPAR is equally suitable for ground-based uplooking measurements as well as downlooking measurements from an airborne platform. In this paper, we describe the principle of operation, present the performance specifications, give an overview of the instrument design, and present validation results. Validation results compare HySPAR measurements to sources of known polarization states. In many cases, HySPAR achieves better than 1% degree of polarization accuracy with further improvements planned. We present reflection measurements from a titanium plate which demonstrates HySPAR's circular polarization measurement capability. This is of particular relevance to enhanced parameter retrievals for non-spherical and optically thick aerosols. A principal advantage of the HySPAR sensor is that it is able to capture a full Stokes (i.e. 4 component) spectrum over a 120 degree swath of the solar principal plane in a single snapshot of the order of 1 second, thus eliminating the possibility of moving clouds contaminating the polarimetry. Many conventional polarimeters compute the polarimetry by assembling multiple time separated images and are thus quite susceptible to yielding incorrect results for such a time varying scene.
{"title":"The Hyperspectral Polarimeter for Aerosol Retrievals (HySPAR): a new instrument for passive remote sensing of aerosols","authors":"S. Jones, F. Iannarilli, P. Kebabian, J. Conant","doi":"10.1109/AERSOL.2005.1494149","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494149","url":null,"abstract":"Aerodyne Research has developed and built a snap-shot imaging spectropolarimeter for aerosol retrievals, based on our patented polarimetric spectral intensity modulation (PSIM) technique. The resulting sensor, the Hyperspectral Polarimeter for Aerosol Retrievals (HySPAR), is capable of capturing, in a single snapshot, a full elliptical Stokes spectrum over 450-900 nm and over a 120 degree field of view. The single beam, single snapshot optical design possesses inherent spectral and polarimetric channel coregistration. HySPAR is equally suitable for ground-based uplooking measurements as well as downlooking measurements from an airborne platform. In this paper, we describe the principle of operation, present the performance specifications, give an overview of the instrument design, and present validation results. Validation results compare HySPAR measurements to sources of known polarization states. In many cases, HySPAR achieves better than 1% degree of polarization accuracy with further improvements planned. We present reflection measurements from a titanium plate which demonstrates HySPAR's circular polarization measurement capability. This is of particular relevance to enhanced parameter retrievals for non-spherical and optically thick aerosols. A principal advantage of the HySPAR sensor is that it is able to capture a full Stokes (i.e. 4 component) spectrum over a 120 degree swath of the solar principal plane in a single snapshot of the order of 1 second, thus eliminating the possibility of moving clouds contaminating the polarimetry. Many conventional polarimeters compute the polarimetry by assembling multiple time separated images and are thus quite susceptible to yielding incorrect results for such a time varying scene.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"48 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116647108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494150
M. de Graaf, P. Stammes
A technique that has gained considerable interest over the last years to monitor aerosol distributions and characterise aerosol source regions has been the use of the absorbing aerosol index (AAI). It has been used extensively to monitor ultraviolet (UV) absorbing aerosols, mainly desert dust and biomass burning aerosols. The AAI is not an aerosol quantity, but a radiation difference in the UV. Its main advantages are its insensitivity to scattering aerosols and clouds, which makes it suitable for global monitoring of absorbing aerosols with sensors with large footprints, and its insensitivity to surface type, which makes it suitable for monitoring aerosols over both sea and land and to study the source regions of UV-absorbing aerosols, which are mainly over land. The European spectrometers GOME and SCIAMACHY have been used to produce daily AAI distributions. GOME data (July 1995-December 2000) have been used to validate the TOMS AAI distributions and complement the TOMS data set in the period July 1995-October 1996, when no TOMS data are available. SCIAMACHY has been measuring from July 2002 to present. The spectrometers measure the entire spectrum from about 240 nm to about 800 nm (GOME) or about 2400 nm (SCIAMACHY). These instruments are used to characterise the spectra of desert dust and biomass burning aerosols scenes. The spectra are used to discriminate between these aerosol types using direct measurements, which can be useful for aerosol retrieval algorithms which at present use aerosol composition climatologies.
{"title":"Global observations and spectral characteristics of desert dust and biomass burning aerosols","authors":"M. de Graaf, P. Stammes","doi":"10.1109/AERSOL.2005.1494150","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494150","url":null,"abstract":"A technique that has gained considerable interest over the last years to monitor aerosol distributions and characterise aerosol source regions has been the use of the absorbing aerosol index (AAI). It has been used extensively to monitor ultraviolet (UV) absorbing aerosols, mainly desert dust and biomass burning aerosols. The AAI is not an aerosol quantity, but a radiation difference in the UV. Its main advantages are its insensitivity to scattering aerosols and clouds, which makes it suitable for global monitoring of absorbing aerosols with sensors with large footprints, and its insensitivity to surface type, which makes it suitable for monitoring aerosols over both sea and land and to study the source regions of UV-absorbing aerosols, which are mainly over land. The European spectrometers GOME and SCIAMACHY have been used to produce daily AAI distributions. GOME data (July 1995-December 2000) have been used to validate the TOMS AAI distributions and complement the TOMS data set in the period July 1995-October 1996, when no TOMS data are available. SCIAMACHY has been measuring from July 2002 to present. The spectrometers measure the entire spectrum from about 240 nm to about 800 nm (GOME) or about 2400 nm (SCIAMACHY). These instruments are used to characterise the spectra of desert dust and biomass burning aerosols scenes. The spectra are used to discriminate between these aerosol types using direct measurements, which can be useful for aerosol retrieval algorithms which at present use aerosol composition climatologies.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"21 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129036567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494144
P. Russell, J. Livingston, O. Dubovik, S. Ramirez, J. Wang, J. Redemann, B. Schmid, M. Box, B. Holben
The NASA Ames airborne Sun photometry program has benefited in many ways from the work of John Reagan. Our water vapor retrieval methods are based on methods published by Prof. Reagan (1987). Designs for our existing instruments and advanced concepts have been influenced by Prof. Reagan's instruments and by his specialized consulting. And our measurements of the Pinatubo volcanic stratospheric aerosol include corrections for diffuse light effects derived by Prof. Reagan and colleagues. The work described here extends Sun photometric diffuse light correction methods to include conditions influenced by the large particles present in airborne desert dust and marine aerosols. Features of the work include parametric equations that easily determine aerosol optical depth (AOD) correction factors from /spl Aring/ngstro/spl uml/m exponents of uncorrected AOD spectra. The parametric equations are derived from results of an analytical expression that accounts for all orders of scattering. Aerosol scattering phase functions are derived from a representative range of dust and marine aerosols with realistic size distributions, compositions (or complex refractive indices), and shapes. This aerosol information is obtained from a wide range of retrievals from the AERONET network of Sun-sky radiometers, as well as airborne in situ measurements especially designed to account for large particles.
{"title":"Diffuse light corrections to Sun photometry of desert dust and marine aerosols","authors":"P. Russell, J. Livingston, O. Dubovik, S. Ramirez, J. Wang, J. Redemann, B. Schmid, M. Box, B. Holben","doi":"10.1109/AERSOL.2005.1494144","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494144","url":null,"abstract":"The NASA Ames airborne Sun photometry program has benefited in many ways from the work of John Reagan. Our water vapor retrieval methods are based on methods published by Prof. Reagan (1987). Designs for our existing instruments and advanced concepts have been influenced by Prof. Reagan's instruments and by his specialized consulting. And our measurements of the Pinatubo volcanic stratospheric aerosol include corrections for diffuse light effects derived by Prof. Reagan and colleagues. The work described here extends Sun photometric diffuse light correction methods to include conditions influenced by the large particles present in airborne desert dust and marine aerosols. Features of the work include parametric equations that easily determine aerosol optical depth (AOD) correction factors from /spl Aring/ngstro/spl uml/m exponents of uncorrected AOD spectra. The parametric equations are derived from results of an analytical expression that accounts for all orders of scattering. Aerosol scattering phase functions are derived from a representative range of dust and marine aerosols with realistic size distributions, compositions (or complex refractive indices), and shapes. This aerosol information is obtained from a wide range of retrievals from the AERONET network of Sun-sky radiometers, as well as airborne in situ measurements especially designed to account for large particles.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124648589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494141
Choo-Hie Lee, C. Park, Jin Hwan Kim
Asian dust in the middle and lower troposphere has been measured continuously by ACA lidar at Suwon station (37.2/spl deg/N-127.6/spl deg/E) during 2002-2004. The lidar system consists of 532/1064 nm laser transmitter and multi-receiving channels. The output optical parameters of the lidar are 532/1064 nm backscatters, 532 nm depolarization ratio, and 1064/532 nm color ratio. During three years of intensive observations of the Asian dust, more than 25 episodes were successfully monitored. The significant dust in March 2002 to May 2004 showed the dust layers are located in the altitude range of 0.4-6 km with the depolarization ratios, 10-30%, the backscattering ratio, 1-5, and the aerosol color ratio, 0.3-0.9 respectively. The backward trajectory applied to those episodes showed that the dust mainly came from Mongolia and Takaramakan deserts.
{"title":"532/1064 nm ACA lidar measurements of Asian dust at Suwon, Korea during 2002/spl sim/2004","authors":"Choo-Hie Lee, C. Park, Jin Hwan Kim","doi":"10.1109/AERSOL.2005.1494141","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494141","url":null,"abstract":"Asian dust in the middle and lower troposphere has been measured continuously by ACA lidar at Suwon station (37.2/spl deg/N-127.6/spl deg/E) during 2002-2004. The lidar system consists of 532/1064 nm laser transmitter and multi-receiving channels. The output optical parameters of the lidar are 532/1064 nm backscatters, 532 nm depolarization ratio, and 1064/532 nm color ratio. During three years of intensive observations of the Asian dust, more than 25 episodes were successfully monitored. The significant dust in March 2002 to May 2004 showed the dust layers are located in the altitude range of 0.4-6 km with the depolarization ratios, 10-30%, the backscattering ratio, 1-5, and the aerosol color ratio, 0.3-0.9 respectively. The backward trajectory applied to those episodes showed that the dust mainly came from Mongolia and Takaramakan deserts.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121067775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494143
Y. Hassebo, Yu Zhao, B. Gross, F. Moshary, S. Ahmed
Satellite measurements do not provide the vertical information needed to assess aerosol transport mechanisms. To supply this information, multiwavelength lidar measurements are needed to study the vertical structure of aerosol events. In support of NASA-INTEX and NOAA-NEAQS transport experiments; we present lidar retrievals, which identify multiple stratified particulate plumes occurring over New York City on 2004 July 21 in support of MODIS imagery. In particular, multiwavelength measurements at CCNY are used to determine the /spl Aring/ngstro/spl uml/m coefficient of the plumes that unambiguously identifies them as fine mode particulates and not cloud particles. A description of our lidar system capabilities and processing algorithms used to process simultaneous backscatter lidar measurements with Aeronet CIMEL Optical Depth (OD) data is presented and back trajectory analysis is used to confirm the source of the plumes to be from Alaskan wild fires. Finally, surface measurements from in situ particle counters are presented and show no enhanced PM2.5 loading. This result is supported by lidar measurements, which confirm that nearly all of the aerosol plumes are located above the normal aerosol boundary layer showing that satellite measurements are often incomplete and is not useful to assess surface air quality. In particular, we show that high PM2.5 events are triggered from more local sources such as the Ohio Basin and climatological conditions which drive the pollution to the surface.
{"title":"Multiwavelength lidar measurements at the City College of New York in support of the NOAA-NEAQS and NASA-INTEX-NA experiments","authors":"Y. Hassebo, Yu Zhao, B. Gross, F. Moshary, S. Ahmed","doi":"10.1109/AERSOL.2005.1494143","DOIUrl":"https://doi.org/10.1109/AERSOL.2005.1494143","url":null,"abstract":"Satellite measurements do not provide the vertical information needed to assess aerosol transport mechanisms. To supply this information, multiwavelength lidar measurements are needed to study the vertical structure of aerosol events. In support of NASA-INTEX and NOAA-NEAQS transport experiments; we present lidar retrievals, which identify multiple stratified particulate plumes occurring over New York City on 2004 July 21 in support of MODIS imagery. In particular, multiwavelength measurements at CCNY are used to determine the /spl Aring/ngstro/spl uml/m coefficient of the plumes that unambiguously identifies them as fine mode particulates and not cloud particles. A description of our lidar system capabilities and processing algorithms used to process simultaneous backscatter lidar measurements with Aeronet CIMEL Optical Depth (OD) data is presented and back trajectory analysis is used to confirm the source of the plumes to be from Alaskan wild fires. Finally, surface measurements from in situ particle counters are presented and show no enhanced PM2.5 loading. This result is supported by lidar measurements, which confirm that nearly all of the aerosol plumes are located above the normal aerosol boundary layer showing that satellite measurements are often incomplete and is not useful to assess surface air quality. In particular, we show that high PM2.5 events are triggered from more local sources such as the Ohio Basin and climatological conditions which drive the pollution to the surface.","PeriodicalId":300217,"journal":{"name":"IEEE Workshop on Remote Sensing of Atmospheric Aerosols, 2005.","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116642380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-04-05DOI: 10.1109/AERSOL.2005.1494152
R. Stone, G. Anderson, E. Andrews, E. Dutton, J. Harris, E. Shettle, A. Berk
Atmospheric aerosols affect the Earth's radiation budget both directly, through interactions with solar and terrestrial radiation, and indirectly, as cloud condensation and ice nuclei. Against the typically clean polar atmospheres, small increases in aerosol concentrations can perturb radiative fluxes significantly. During spring 2002, dust storms from the deserts of China and Mongolia were tracked over the Arctic, establishing that such remote regions are not immune to the dispersion of Asian dust. Increased aerosol optical depths and lidar measurements at Barrow, AK, in conjunction with trajectory analyses and dust transport provide corroborating evidence for transport of dust to the Arctic. The primary impact of the dust layer can be determined by examining its radiative properties relative to the underlying snow and intervening pristine background environment. Through a sequence of ground-based visibility measurements of the aerosols coupled with lidar measurements of the layer height, a realistic dust cloud was ported into Moderate Resolution Transmittance (MODTRANT/spl trade/) code. A suite of MODTRAN calculations, constructed around this cloud description, provided spectrally integrated forcing terms at the surface, along with estimates of the local heating/cooling at altitude, with and without the dust cloud. This then led to a closure experiment where MODTRAN predictions of surface forcing are in remarkably good agreement with measurements for a set of solar-zenith angles and aerosol optical depths.
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