118 research outputs found

    The Cloud-Aerosol Transport System (CATS): a New Lidar for Aerosol and Cloud Profiling from the International Space Station

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    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064, 532, 355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time data capability of the ISS will enable CATS to support operational applications such as air quality and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a summary of the science objectives and simulated data

    The Cloud-Aerosol Transport System (CATS): A New Lidar for Aerosol and Cloud Profiling from the International Space Station

    Get PDF
    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064,532,355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time (NRT) data capability ofthe ISS will enable CATS to support operational applications such as aerosol and air quality forecasting and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a summary of the science objectives and simulated data. Input from the ICAP community is desired to help plan our NRT mission goals and interactions with ICAP forecasters

    Tropospheric ozone sources and wave activity over Mexico City and Houston during MILAGRO/Intercontinental Transport Experiment (INTEX-B) Ozonesonde Network Study, 2006 (IONS-06)

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    During the INTEX-B (Intercontinental Chemical Transport Experiment)/ MILAGRO (Megacities Initiative: Local and Global Research Observations) experiments in March 2006 and the associated IONS-06 (INTEX Ozonesonde Network Study; <a href="http://croc.gsfc.nasa.gov/intexb/ions06.html" target="_blank">http://croc.gsfc.nasa.gov/intexb/ions06.html</a>), regular ozonesonde launches were made over 15 North American sites. The soundings were strategically positioned to study inter-regional flows and meteorological interactions with a mixture of tropospheric O<sub>3</sub> sources: local pollution; O<sub>3</sub> associated with convection and lightning; stratosphere-troposphere exchange. The variability of tropospheric O<sub>3</sub> over the Mexico City Basin (MCB; 19° N, 99° W) and Houston (30° N, 95° W) is reported here. MCB and Houston profiles displayed a double tropopause in most soundings and a subtropical tropopause layer with frequent wave disturbances, identified through O<sub>3</sub> laminae as gravity-wave induced. Ozonesondes launched over both cities in August and September 2006 (IONS-06, Phase 3) displayed a thicker tropospheric column O<sub>3</sub> (~7 DU or 15–20%) than in March 2006; nearly all of the increase was in the free troposphere. In spring and summer, O<sub>3</sub> laminar structure manifested mixed influences from the stratosphere, convective redistribution of O<sub>3</sub> and precursors, and O<sub>3</sub> from lightning NO. Stratospheric O<sub>3</sub> origins were present in 39% (MCB) and 60% (Houston) of the summer sondes. Comparison of summer 2006 O<sub>3</sub> structure with summer 2004 sondes (IONS-04) over Houston showed 7% less tropospheric O<sub>3</sub> in 2006. This may reflect a sampling contrast, August to mid-September 2006 instead of July-mid August 2004

    CATS Near Real Time Data Products: Applications for Assimilation Into the NASA GEOS-5 AGCM

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    From February 2015 through October 2017, the NASA Cloud-Aerosol Transport System (CATS) backscatter lidar operated on the International Space Station (ISS) as a technology demonstration for future Earth Science Missions, providing vertical measurements of cloud and aerosols properties. Owing to its location on the ISS, a cornerstone technology demonstration of CATS was the capability to acquire, process, and disseminate near-real time (NRT) data within 6 hours of observation time. CATS NRT data has several applications, including providing notification of hazardous events for air traffic control and air quality advisories, field campaign flight planning, as well as for constraining cloud and aerosol distributions in via data assimilation in aerosol transport models. Recent developments in aerosol data assimilation techniques have permitted the assimilation of aerosol optical thickness (AOT), a 2-dimensional column integrated quantity that is reflective of the simulated aerosol loading in aerosol transport models. While this capability has greatly improved simulated AOT forecasts, the vertical position, a key control on aerosol transport, is often not impacted when 2-D AOT is assimilated. Here, we present preliminary efforts to assimilate CATS aerosol observations into the NASA Goddard Earth Observing System version 5 (GEOS-5) atmospheric general circulation model and assimilation system using a 1-D Variational (1-D VAR) ensemble approach, demonstrating the utility of CATS for future Earth Science Missions

    CATS Version 2 Aerosol Feature Detection and Applications for Data Assimilation

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    The Cloud Aerosol Transport System (CATS) lidar has been operating onboard the International Space Station (ISS) since February 2015 and provides vertical observations of clouds and aerosols using total attenuated backscatter and depolarization measurements. From February March 2015, CATS operated in Mode 1, providing backscatter and depolarization measurements at 532 and 1064 nm. CATS began operation in Mode 2 in March 2015, providing backscatter and depolarization measurements at 1064 nm and has continued to operate to the present in this mode. CATS level 2 products are derived from these measurements, including feature detection, cloud aerosol discrimination, cloud and aerosol typing, and optical properties of cloud and aerosol layers. Here, we present changes to our level 2 algorithms, which were aimed at reducing several biases in our version 1 level 2 data products. These changes will be incorporated into our upcoming version 2 level 2 data release in summer 2017. Additionally, owing to the near real time (NRT) data downlinking capabilities of the ISS, CATS provides expedited NRT data products within 6 hours of observation time. This capability provides a unique opportunity for supporting field campaigns and for developing data assimilation techniques to improve simulated cloud and aerosol vertical distributions in models. We additionally present preliminary work toward assimilating CATS observations into the NASA Goddard Earth Observing System version 5 (GEOS-5) global atmospheric model and data assimilation system

    Convective and Wave Signatures in Ozone Profiles Over the Equatorial Americas: Views from TC4 (2007) and SHADOZ

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    During the months of July-August 2007 NASA conducted a research campaign called the Tropical Composition, Clouds and Climate Coupling (TC4) experiment. Vertical profiles of ozone were measured daily using an instrument known as an ozonesonde, which is attached to a weather balloon and launch to altitudes in excess of 30 km. These ozone profiles were measured over coastal Las Tablas, Panama (7.8N, 80W) and several times per week at Alajuela, Costa Rica (ION, 84W). Meteorological systems in the form of waves, detected most prominently in 100- 300 in thick ozone layer in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves ("GW," possibly Kelvin waves), occur with similar stricture and frequency over the Paramaribo (5.8N, 55W) and San Cristobal (0.925, 90W) sites of the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. The gravity wave labeled layers in individual soundings correspond to cloud outflow as indicated by the tracers measured from the NASA DC-8 and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi-horizontal displacements, referred to as Rossby waves, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extra-tropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999-2007 Paramaribo and San Cristobal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated meteorological waves appear to dominate ozone transport in the tropical tropopause layer

    A European lens upon adult and lifelong learning in Asia

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    In this article, we seek to assess the extent to which adult and lifelong learning policies and practices in Asia have distinctiveness by comparison to those found in western societies, through an analysis of inter-governmental, national and regional policies in the field. We also inform our study through the analysis of the work of organisations with an international remit with a specific focus on Asia and Europe. In one case, the Asia–Europe Meeting Lifelong Learning (ASEM LLL) Hub has a specific function of bringing together researchers in Asia and Europe. In another, the PASCAL Observatory has had a particular focus on one aspect of lifelong learning, that of learning cities, with a concentration in its work on Asia and Europe. We focus on learning city development as a particular case of distinction in the field. We seek to identify the extent to which developments in the field in Asia have influenced and have been influenced by practices elsewhere in world, especially in Europe, and undertake our analysis using theories of societal learning/the learning society, learning communities and life-deep learning. We complement our analysis through assessment of material contained in three dominant journals in the field, the International Journal of Lifelong Education, the International Review of Education and Adult Education Quarterly, each edited in the west

    The transformative potential of international service-learning at a university with a Christian foundation in the UK

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    This article draws upon the findings of a study at Liverpool Hope University (LHU) into the transformative nature of International Service-Learning (ISL) experiences for student participants. This research is concerned with the implications of these findings for professional practice, in particular how ISL is constructed in Higher Education policy and practice. Recognising the problematic nature of this endeavor, this article responds to a call for discussion around pedagogical approaches underpinning counter-cultural and critical service programmes aligned with the radical principles of the Catholic social teaching. This study is grounded in a holistic conceptualisation of transformative learning that demands looking beyond an epistemological process that involves shifts in worldview and habits of mind to an ontological process that accounts for changes to our being in the world. It investigated how LHU students describe their ongoing experience of ISL and explored the conditions for learning and the associated transformative processes and outcomes in this context. Data analysis involved phenomenological description, constant comparative thematic analysis followed by a critical, hermeneutical analysis. This article will explicate the themes of moral and spiritual learning that emerged as part of a broader framework. In particular, it was found that the development of authentic relationships between travelling companions, accompanying tutors and partners overseas is central to learning that is reciprocated and provides a model of the transformative process in this context. This article concludes that this presents a pedagogical approach grounded in social justice that enables ISL to reach its transformative potential
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