Showing papers on "Cloud computing published in 1987"
TL;DR: In this article, the statistical properties of cloud ensembles under a specified large-scale environment, such as mass flux by cloud drafts and vertical velocity as well as the condensation and evaporation associated with these cloud drafts, are examined using a three-dimensional numerical cloud ensemble model described by Soong and Ogura (1980) and Tao and Soong (1986).
Abstract: The statistical properties of cloud ensembles under a specified large-scale environment, such as mass flux by cloud drafts and vertical velocity as well as the condensation and evaporation associated with these cloud drafts, are examined using a three-dimensional numerical cloud ensemble model described by Soong and Ogura (1980) and Tao and Soong (1986). The cloud drafts are classified as active and inactive, and separate contributions to cloud statistics in areas of different cloud activity are then evaluated. The model results compare well with results obtained from aircraft measurements of a well-organized ITCZ rainband that occurred on August 12, 1974, during the Global Atmospheric Research Program's Atlantic Tropical Experiment.
130 citations
TL;DR: The first International Satellite Cloud Climatology Project Regional Experiment (FIRE) as discussed by the authors was designed to study the roles of clouds, in particular marine stratocumulus and cirrus-cloud systems, in the global climate.
Abstract: The First International Satellite Cloud Climatology Project Regional Experiment (FIRE) designed to study the roles of clouds, in particular marine stratocumulus and cirrus-cloud systems, in the global climate is discussed The objectives of FIRE are: (1) to develop a cloud-classification scheme; (2) to validate and improve satellite cloud-retrieval techniques; (3) to improve cloud radiation models; (4) to collect cloud space/time statistics; (5) to improve cloud dynamics models; and (6) to validate and improve GCM cloud parameterizations The methods used to acquire extended time data and intensive field observations are described The extended time and intensive field data collected during the FIRE are to be archived in the NASA Pilot Climate Data System at Goddard Space Flight Center
100 citations
TL;DR: Spatial variances are introduced as additional parameters of the classification, with the aim to better separate clouds from the surface and the different kinds of more or less homogeneous cloud classes.
Abstract: New developments of a cloud classification scheme based on histogram clustering by a statistical method are presented. Use of time series of geostationary satellite pictures as well as for construction of composite images representative of the surface properties and then for the identification of significative cloud classes is discussed. Spatial variances are introduced as additional parameters of the classification, with the aim to better separate clouds from the surface and the different kinds of more or less homogeneous cloud classes.
70 citations
24 Aug 1987
TL;DR: In this paper, total cloud cover and cloud type amounts over both land and ocean, based on data from FNOC and COADS, were calculated using the Extended Edited Synoptic Cloud Report Archive.
Abstract: Total cloud cover and cloud type amounts over both land and ocean, based on data from FNOC and COADS
Superseded by the Extended Edited Synoptic Cloud Report Archive See RELATED DATASETS below
47 citations
TL;DR: In this paper, a method for estimating the cloud effect on remote sensing is described, and it is applied to cloudiness in several climatological conditions, and the relation between cloud reflectance and cloud size is studied.
Abstract: A method for estimating the cloud effect on remote sensing is described, and it is applied to cloudiness in several climatological conditions. The algorithm is based on the Haurwitz (1948) measurements of the cloud layer transmission of solar radiation for an overcast sky and on an empirical interpolation of data for broken cloudiness by Pochop et al. (1968). Radiances for a sunny area observed directly from space and through a cloud, and for a shady area observed from space and through a cloud are computed. Methods for detecting the cloud effect from satellite images are discussed. The relation between cloud reflectance and cloud size is studied. It is observed that the subpixel clouds affect the detected radiance and vegetation index, and the effect depends on the cloud types and the dependence of the cloud transmissivity on cloud fraction. Procedures for decreasing or eliminating cloud effect are examined.
44 citations
TL;DR: It has been demonstrated that a cloud field image can be quantitatively defined by a small set of parameters and synthesized surrogates can be reconstructed from these model parameters, enabling cloud climatology to be studied quantitatively.
Abstract: A modeling method for the quantitative description of remotely sensed cloud field images is presented. A two-dimensional texture modeling scheme based on one-dimensional time series procedures is adopted for this purpose. The time series procedure used is the seasonal autoregressive, moving average (ARMA) process in Box and Jenkins. Cloud field properties such as directionality, clustering and cloud coverage can be retrieved by this method. It has been demonstrated that a cloud field image can be quantitatively defined by a small set of parameters and synthesized surrogates can be reconstructed from these model parameters. This method enables cloud climatology to be studied quantitatively.
14 citations
TL;DR: In this paper, the authors proposed a dynamic threshold method to adjust the infrared threshold to achieve the highest correlation between the threshold-derived cloud cover and the mean emitted radiance for mesoscale-sized subregions within the scene.
Abstract: Errors in cloud cover derived by using a fixed threshold applied to imagery data depend not only on the fractional cover but also on cloud size. As a result, a fixed threshold applied to two scenes having the same cloud cover will produce different estimates of the cover when the clouds in the two scenes have different sizes. To allow for this influence due to cloud size, a dynamic threshold method is presented. In this method an infrared threshold is adjusted to achieve the highest correlation between the threshold-derived cloud cover and the mean emitted radiance for mesoscale-sized subregions within the scene. For single-layered cloud systems this threshold achieves a cancellation of errors in the cloud cover for the subregions so that the resulting cloud cover for the region and the associated estimates of cloud properties are in fair agreement with estimates obtained using the spatial coherence method. The agreement illustrates the validity of the layered cloud model used in different ways by the two methods. The performance of the dynamic threshold method is contrasted with that of a fixed threshold applied to the same data in order to illustrate the merits of applying a scene-dependent threshold.
11 citations
TL;DR: In this article, the speed of a toxic or flammable heavy gas cloud is determined by an equation of motion for translation of the cloud to determine its hazardous effect, and an equation for translation is proposed.
11 citations
Book•
01 Jan 1987
9 citations
01 Nov 1987
4 citations
01 Apr 1987
TL;DR: In this paper, the authors used a quasi-Lagrangian approach to make the forecast of 5LAYER, HRCP, and TRONEW models for the AFGWC.
Abstract: : AFGWC has three cloud forecast models: Five-Layer (5LAYER), High Resolution Cloud Prognosis (HRCP), and Tropical Cloud Forecasting Model (TRONEW) . These models satisfy a wide range of requirements and have been in operation since the early 1970s. The 5LAYER model makes extra-tropical forecasts for periods up to 48 hours. Forecasts of layer and total cloud, cloud type, layer temperatures, and icing and weather conditions are made. The 5LAYER model uses a quasi-Lagrangian approach to make these forecasts. The trajectories needed for these forecasts are computed from the AWS Global Spectral Model (GSM) derived wind forecasts. The 5LAYER moisture is initialized from the Real-Time Nephanalysis Model (RTNEPH) layer cloud-amount and the Multi-layer Analysis Model (MULTAN) layer dew-point depression. The 5LAYER temperatures are initialized from the High Resolution Analysis System (HIRAS) and GSM derived temperatures. The High Resolution Cloud Prognosis (HRCP) model combines RTNEPH analyzed cloud input with 5LAYER trajectories to produce high resolution (25 nm) , short-range (out to 9 hour) cloud forecasts. The TRONEW model uses the analyzed RTNEPH cloud to make 24 hour persistence cloud forecasts for the tropics.
01 Jan 1987
TL;DR: In this article, a physically-based one-dimensional interactive cloud formation model was developed, which incorporates parameterizations of precipitation and evaporation, and the model can predict cloud cover and liquid water content as a function of temperature distribution.
Abstract: A physically-based one-dimensional interactive cloud formation model has been developed, which incorporates parameterizations of precipitation and evaporation. The model can predict cloud cover and liquid water content as a function of temperature distribution. The model-computed cloud liquid water content compares well with the statistical average based on aircraft measurements. This model is used in connection with a one-dimensional radiative-turbulent climate model to investigate temperature changes due to doubling of CO2. The incorporation of an interactive cloud formation program, in which cloud cover and liquid water content are generated in accordance with the temperature distribution, reduces the sensitivity of temperature increases, as compared with the case when cloud cover and/or liquid water content are fixed in the climate model. Preliminary results from a two-dimensional climate model coupled with a modified cloud program, including horizontal transports also support the finding that clouds appear to stabilize the perturbed climate due to external radiative forcings.
01 Jan 1987
TL;DR: In this article, the zonal distribution of cloud is applied to the radiative fluxes as predicted by an energy balance model and special channel cloud discrimination is discussed with reference to Landsat thematic mapper.
Abstract: Global satellite-derived cloud climatologies are considered and the results of an automated cloud analysis model are presented. The zonal distribution of cloud is applied to the radiative fluxes as predicted by an energy balance model. Special channel cloud discrimination is discussed with reference to Landsat thematic mapper.
Journal Article•
01 Jan 1987
TL;DR: In this paper, a combination of near infrared, thermal infrared, and thermal microwave radiometry was used to retrieve cloud physical properties, such as optical thickness, cloud top pressure, volume scattering coefficient, hydrometeor phase and size, and cloud top temperature, ice water content and liquid water content.
Abstract: There has been growing interest in the use of a combination of near infrared, thermal infrared, and thermal microwave radiometry to retrieve cloud physical properties. The cloud properties to be retrieved are the cloud optical thickness, cloud top pressure, volume scattering coefficient, hydrometeor phase and size, cloud top temperature, ice water content and/or liquid water content and cloud geometrical thickness. The retrieval effort will make use of measurements from the Multispectral Cloud Radiometer (MCR), Cloud Lidar System (CLS), and Advanced Microwave Moisture Sounder (AMMS).
TL;DR: In this paper, the fundamental goals and scientific problems facing researchers in purposeful cloud modification and applicable to air quality pertaining to unintentional cloud modification are defined, including experimental design and verification, transport and dispersion, aerosol and hydrometeor evolution and removal, and the interactive nature of chemical, microphysical, dynamical and other cloud processes on micro-to mesoscales.
Abstract: Fundamental goals and scientific problems facing researchers in purposeful cloud modification and applicable to air quality pertaining to unintentional cloud modification are defined. These encompass experimental design and verification, transport and dispersion, aerosol and hydrometeor evolution and removal, and the interactive nature of chemical, microphysical, dynamical and other cloud processes on micro- to mesoscales. Some recent advances in purposeful weather modification are reviewed and parallels are drawn to wet chemistry and unintentional cloud modification. Gains to be made in further cross-fertilization of the disciplines are suggested.