35 research outputs found

    Empirical determination of the effects of clouds on the Earth's Radiation Budget over the Pacific Ocean

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    The main objectives of this research has been to learn how clouds interact with the Earth's Radiation Budget (ERB). This broad goal has been approached in three distinct ways. The first has been to analyze the direct effect cloud amount has on the radiative components of the ERB. The second has been to investigate the indirect effects clouds and water vapor may have on the climate as a feedback mechanism. And finally an attempt has been made to simulate the findings in a simple radiative-convective climate model. This report will summarize these three phases of the research

    The effect of clouds on the earth's radiation budget

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    The radiative fluxes from the Earth Radiation Budget Experiment (ERBE) and the cloud properties from the International Satellite Cloud Climatology Project (ISCCP) over Indonesia for the months of June and July of 1985 and 1986 were analyzed to determine the cloud sensitivity coefficients. The method involved a linear least squares regression between co-incident flux and cloud coverage measurements. The calculated slope is identified as the cloud sensitivity. It was found that the correlations between the total cloud fraction and radiation parameters were modest. However, correlations between cloud fraction and IR flux were improved by separating clouds by height. Likewise, correlations between the visible flux and cloud fractions were improved by distinguishing clouds based on optical depth. Calculating correlations between the net fluxes and either height or optical depth segregated cloud fractions were somewhat improved. When clouds were classified in terms of their height and optical depth, correlations among all the radiation components were improved. Mean cloud sensitivities based on the regression of radiative fluxes against height and optical depth separated cloud types are presented. Results are compared to a one-dimensional radiation model with a simple cloud parameterization scheme

    Development of a 2009 Stable Lights Product using DMSP-OLS data

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    Since 1994, NGDC has had an active program focused on global mapping of nighttime lights using the data collected by the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS) sensors.  The basic product is a global annual cloud-free composite, which averages the OLS visible band data for one satellite from the cloud-free segments of individual orbits.  Over the years, NGDC has developed automatic algorithms for screening the quality of the nighttime visible band observations to remove areas contaminated by sunlight, moonlight, and the presence of clouds.  In the Stable Lights product generation, fires and other ephemeral lights are removed based on their high brightness and short duration.  Background noise is removed by setting thresholds based on visible band values found in areas known to be free of detectable lights.  In 2010, NGDC released the version 4 time series of Stable Lights, spanning the years 1992-2009.  These are available online at <http://www.ngdc.noaa.gov/dmsp/downloadV4composites.html>

    Methods Used For the 2006 Radiance Lights

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    The Operational Linescan System (OLS) flown on the Defense Meteorological Satellite Program (DMSP) satellites, has a unique capability to record low light imaging data at night worldwide. These data are archived at the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center (NGDC).  The useful data record stretches back to 1992 and is ongoing. The OLS visible band detector observes radiances about one million times dimmer than most other Earth observing satellites. The sensor is typically operated in a high gain setting to enable the detection of moonlit clouds. However, with six bit quantization and limited dynamic range, the recorded data are saturated in the bright cores of urban centers. A limited set of observations have been obtained at low lunar illumination were obtained where the gain of the detector was set significantly lower than its typical operational setting (sometimes by a factor of 100). By combining these sparse data acquired at low gain settings with the operational data acquired at high gain settings, we have produced a global nighttime lights product for 2006 with no sensor saturation.  This product can be related to radiances based on the pre-flights sensor calibration

    Mapping the Constructed Surface Area Density for China

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    Efforts to map the constructed surface area density of the world using nighttime satellite imagery have typically been validated using aerial photography or high resolution satellite imagery in the United States and extrapolating regression parameters to countries outside of the United States. In a previous study, we found China to have ‘paved’ more of the planet than any other country (~87,00 km2). Here we use a google earth based web application to validate our estimates of anthropogenic impervious surface (constructed area density) in China using actual imagery of China.  ‘Paving the Planet’ is a universal phenomenon – akin to clothing – and represents one of the primary anthropogenic modifications of the environment.  Expansion in population numbers and economies combined with the increased use of automobiles has led to the sprawl of development and a wide proliferation of constructed impervious surfaces. Constructed impervious surfaces are both hydrological and ecological disturbances.  However, constructed surfaces are different from most other types of disturbances in that recovery is arrested through the use of materials that are resistant to decay and are actively maintained. The same characteristics that make impervious surfaces ideal for use in construction produce a series of effects on the environment.  We present a new map of the density of constructed surface in China derived from DMSP nighttime lights and LandScan population count data

    NASA's Land, Atmosphere Near Real-Time Capability for EOS (LANCE): Delivering Data and Imagery to Meet the Needs of Near Real-Time Applications

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    NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) is a virtual system that provides near real-time EOS data and imagery from the AIRS, AMSR2, LIS (ISS), MISR, MLS, MODIS, MOPITT, OMI, OMPS, and VIIRS instruments, to meet the needs of scientists and application users interested in monitoring a wide variety of natural and man-made phenomena. NRT imagery from LANCE are available through NASA's Global Imagery Browse Services (GIBS), Worldview, FIRMS and most recently through Worldview Snapshots a low band width application that has replaced the Rapid Response Subsets. Over the past year: data and imagery from the Lightning Imaging Sensor (LIS) on board the International Space Station (ISS), OMPS and VIIRS-Land have been added to LANCE. In the coming year LANCE will integrate the MODIS NRT Global Flood product, VIIRS Black Marble nighttime lights and Cloud Mask and Aerosol Dark Target from VIIRS Atmosphere. Here we provide a brief overview of LANCE, focusing on what's new and describing how these new data sets have been used to monitor lightning flashes, hurricanes and fires. For more information on LANCE visit: https://earthdata.nasa.gov/lance

    Expanding NASA's Land, Atmosphere Near Real-Time Capability for EOS (LANCE)

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    NASA's Land, Atmosphere Near real-time Capability for EOS (LANCE) is a virtual system that provides near real-time EOS data and imagery to meet the needs of scientists and application users interested in monitoring a wide variety of natural and man-made phenomena in near real-time. Over the last year: near real-time data and imagery from MOPITT, MISR, OMPS and VIIRS (Land and Atmosphere), the Fire Information for Resource Management System (FIRMS) has been updated and LANCE has begun the process of integrating the Global NRT flood, and Black Marble products. In addition, following the AMSU-A2 instrument anomaly in September 2016, AIRS-only products have replaced the NRT level 2 AIRS+AMSU products. This presentation provides a brief overview of LANCE, describes the new products that are recently available and contains a preview of what to expect in LANCE over the coming year

    The principal neurons of the medial nucleus of the trapezoid body and NG2+ glial cells receive coordinated excitatory synaptic input

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    Glial cell processes are part of the synaptic structure and sense spillover of transmitter, while some glial cells can even receive direct synaptic input. Here, we report that a defined type of glial cell in the medial nucleus of the trapezoid body (MNTB) receives excitatory glutamatergic synaptic input from the calyx of Held (CoH). This giant glutamatergic terminal forms an axosomatic synapse with a single principal neuron located in the MNTB. The NG2 glia, as postsynaptic principal neurons, establish synapse-like structures with the CoH terminal. In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, α-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor–mediated evoked and spontaneous synaptic input. Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input. This shows that an NG2+ glial cell and a postsynaptic neuron share presynaptic terminals
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