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Book Energy Research Abstracts

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995-10 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Point Comparisons of Total Cloud Cover from Satellites and from Surface Observations

Download or read book Point Comparisons of Total Cloud Cover from Satellites and from Surface Observations written by Patrick J. O'Reilly and published by . This book was released on 1973 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report compares cloud-cover observations made by ground observers and relative cloud-cover estimates determined from satellite-measured brightness values. Comparisons are made when each type of cloud (9 low type, 9 middle type, and 9 high type) are found alone and also with various combinations taken over the China mainland and portions of Southeast Asia. Satellite observations from the ESSA and ITOS series of satellites are used. Both tabulated and graphical presentations of the results are included along with the author's comments on the investigative procedures and findings.

Book Comparisons of Cloud Cover Estimates and Cloud Fraction Profiles from ARM s Cloud detecting Instruments and GOES 8 Data

Download or read book Comparisons of Cloud Cover Estimates and Cloud Fraction Profiles from ARM s Cloud detecting Instruments and GOES 8 Data written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward- and downward-looking remote-sensing instruments to measure the horizontal and vertical distributions of clouds across its Southern Great Plains (SGP) site. No single instrument is capable of completely determining these distributions over the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous Radiative Flux (IRF) groups; these groups embody the primary strategies through which ARM expects to achieve its objectives of developing and testing cloud formation parameterizations (USDOE, 1996). Collectively, however, the data from ARM's cloud-detecting instruments offer the potential for such a three-dimensional characterization. Data intercomparisons, like the ones illustrated in this paper, are steps in this direction. Examples of some initial comparisons, involving satellite, millimeter cloud radar, whole sky imager and ceilometer data, are provided herein. that many of the lessons learned can later be adapted to cloud data at the Boundary and Extended Facilities. Principally, we are concerned about: (1) the accuracy of various estimates of cloud properties at a single point, or within a thin vertical column, above the CF over time, and (2) the accuracy of various estimates of cloud properties over the Cloud and Radiation Testbed (CART) site, which can then be reduced to single, representative profiles over time. In the former case, the results are usable in the IRF and SCM strategies; in the latter case, they satisfy SCM needs specifically. The Whole Sky Imager (WSI) and ceilometer data used in one study were collected at the SGP CF between October 1 and December 31, 1996 (Shields, et. al., 1990). This three-month period, corresponding to the first set of WSI data released by ARM's Experiment Center, was sufficiently long to reveal important trends (Rodriguez, 1998).

Book Government Reports Announcements Index

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Comparisons of Cloud Cover and Cloud Fractions Using Remote sensing Retrievals

Download or read book Comparisons of Cloud Cover and Cloud Fractions Using Remote sensing Retrievals written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward- and downward-looking remote-sensing instruments to measure the horizontal and vertical distributions of clouds across its Southern Great Plains (SGP) site. No single instrument is capable of completely determining these distributions over the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous Radiative Flux (IRF) groups; these groups embody the primary strategies through which ARM expects to achieve its objectives of developing and testing cloud formation (USDOE, 1996). Collectively, however, the data from ARM's cloud-detecting instruments offer the potential for such a three-dimensional characterization. Data intercomparisons, like the ones illustrated here, are steps in this direction. Specifically, they are valuable because they help: provide a measure of uncertainty in ARM's measurement capabilities, calibrate retrieval methods and refine algorithms and concepts. In the process, we are forced to think of meaningful ways in which measurements from different instruments can be compared and, perhaps, combined. While the ultimate goal of this particular effort is to develop the ability to accurately characterize cloud fields in three dimensions over time at the SGP site, along the way we will address such questions as ''which source, or combination of cloud data sources, offers a best estimate product?'' and ''how can cloud observations be used to evaluate the representation of clouds in numerical models?''. Examples of some initial comparisons, involving satellite, millimeter cloud radar, whole sky imager and ceilometer data, are provided herein.

Book A New NASA MSFC Mission Analysis Global Cloud Cover Data Base

Download or read book A New NASA MSFC Mission Analysis Global Cloud Cover Data Base written by S. C. Brown and published by . This book was released on 1985 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A global cloud cover data set, derived from the USAF 3D NEPH Analysis, was developed for use in climate studies and for Earth viewing applications. This data set contains a single parameter - total sky cover - separated in time by 3 or 6 hour intervals and in space by approximately 50 nautical.miles. Cloud cover amount is recorded for each grid point (of a square grid) by a single alphanumeric character representing each 5 percent increment of sky cover. The data are arranged in both quarterly and monthly formats. The data base currently provides daily, 3-hr observed total sky cover for the Northern Hemisphere from 1972 through 1977 less 1976. For the Southern Hemisphere, there are data at 6-hr intervals for 1976 through 1978 and at 3-hr intervals for 1979 and 1980. More years of data are being added. To validate the data base, the percent frequency of or = 0.3 and or = 0.8 cloud cover was compared with ground observed cloud amounts at several locations with generally good agreement. Mean or other desired cloud amounts can be calculated for any time period and any size area from a single grid point to a hemisphere. The data base is especially useful in evaluating the consequence of cloud cover on Earth viewing space missions. The temporal and spatial frequency of the data allow simulations that closely approximate any projected viewing mission. No adjustments are required to account for cloud continuity.

Book Cloud Cover Determination in Polar Regions from Satellite Imagery

Download or read book Cloud Cover Determination in Polar Regions from Satellite Imagery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives are to develop a suitable validation data set for evaluating the effectiveness of the International Satellite Cloud Climatology Project (ISCCP) algorithm for cloud retrieval in polar regions, to identify limitations of current procedures and to explore potential means to remedy them using textural classifiers, and to compare synoptic cloud data from model runs with observations. Toward the first goal, a polar data set consisting of visible, thermal, and passive microwave data was developed. The AVHRR and SMMR data were digitally merged to a polar stereographic projection with an effective pixel size of 5 sq km. With this data set, two unconventional methods of classifying the imagery for the analysis of polar clouds and surfaces were examined: one based on fuzzy sets theory and another based on a trained neural network. An algorithm for cloud detection was developed from an early test version of the ISCCP algorithm. This algorithm includes the identification of surface types with passive microwave, then temporal tests at each pixel location in the cloud detection phase. Cloud maps and clear sky radiance composites for 5 day periods are produced. Algorithm testing and validation was done with both actural AVHRR/SMMR data, and simulated imagery. From this point in the algorithm, groups of cloud pixels are examined for their spectral and textural characteristics, and a procedure is developed for the analysis of cloud patterns utilizing albedo, IR temperature, and texture. In a completion of earlier work, empirical analyses of arctic cloud cover were explored through manual interpretations of DMSP imagery and compared to U.S. Air Force 3D-nephanalysis. Comparisons of observed cloudiness from existing climatologies to patterns computed by the GISS climate model were also made. Barry, R. G. and Key, J. Unspecified Center NASA-CR-186096, NAS 1.26:186096 NAG5-898...

Book Automated Determination of Cloud Cover from Satellite Images Based on Image Processing

Download or read book Automated Determination of Cloud Cover from Satellite Images Based on Image Processing written by Commission of the European Communities and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Comparaison Et Analyse Statistique Des Propri t s Nuageuses D riv es Des Instruments POLDER Et MODIS Dans Le Cadre de L exp rience Spatiale A Train

Download or read book Comparaison Et Analyse Statistique Des Propri t s Nuageuses D riv es Des Instruments POLDER Et MODIS Dans Le Cadre de L exp rience Spatiale A Train written by Shan Zeng and published by . This book was released on 2011 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The A-Train observations provide an unprecedented opportunity for synchronous monitoring of the entire atmosphere including clouds at the global scale. In this study we illustrate a statistical analysis and comparisons of cloud cover, thermodynamic phase and cloud optical thickness mainly derived from the coincident POLDER (Polarization_and_Directionality_of_the_Earth_Reflectance), and MODIS (MODerate_Resolution_Imaging Spectroradiometer) sensors in the A-Train constellation. We presented first the results of an extensive study of the regional and seasonal variations of cloud cover from POLDER and MODIS and discuss the possible factors leading to differences between them, among which are the spatial resolution, aerosols, cirrus and particular surfaces. Cloud top phase products were then compared and discussed in view of cloud vertical structure and optical properties derived simultaneously from collocated CALIOP (Cloud-Aerosol_Lidar_with_Orthogonal_Polarization, another A-Train member) observations, which allow to identify and qualify potential biases present in the 3 considered dataset. Among those, we discussed the impact of observed geometries, thin cirrus, aerosols, snow/ice surfaces, multilayer and fractional cloud cover on global statistics of cloud phase derived from POLDER and MODIS passive measurements. Based on these analyses we selected cloud retrievals of high confidence to study the global and regional vertical ice-water transition and the variations of this transition with cloud formation and development regimes, particularly the impact of large-scale dynamics and cloud microphysics.Cloud optical thicknesses were finally studied. The impacts of spatial resolution, cloud microphysics and heterogeneity are mainly discussed for the understanding of the significant biases on optical thickness from the two sensors.