Abstract: Landsat Multispectral Scanner (MSS) digital data are used to remotely sense cumulus cloud properties such as cloud fraction and cloud reflectance, along with the distribution of cloud number and cloud fraction as a function of cloud size. The analysis is carried out for four cumulus fields covering regions approximately 150 km square. Results for these initial cloud fields indicate that: (1) the common intuitive model of clouds as nearly uniform reflecting surfaces is a poor representation of cumulus clouds, (2) the cumulus clouds were often multicelled, even for clouds as small as 1 km in diameter, (3) cloud fractional coverage derived using a simple reflectance threshold is sensitive to the chosen threshold even for 57-meter resolution Landsat data, (4) the sensitivity of cloud fraction to changes in satellite sensor resolution is less sensitive than suggested theoretically, and (5) the Landsat derived cloud size distributions show encouraging similarities among the cloud fields examined.

Abstract: A cloud chemistry model is formulated in term of continuity equations for chemical species in the aqueous and aqueous phases within the cloud. The model includes scavenging of SO2, HNO3, HN3, H2O3, and sulphate aerosol particles. Calculations have been performed within the framework of a three-dimensional convective cloud model. The results are compared with aircraft measurements of cloud water chemistry.

Abstract: A multispectral cloud analysis technique using NOAA-7 Advanced Very High Resolution Radiometer (AVHRR) infrared imagery was developed and tested using the AFGL Man-computer Interactive Data Access System (McIDAS) and the AFGL Interactive Meteorological System (AIMS). Fractional cloud amount and cloud top heights are computed for low-level clouds at night, including subpixel resolution clouds (i.e., clouds which only partially fill a sensor's field of view). Multispectral analysis offers a technique for detecting low cloud, which is better than cloud analysis using single channel infrared imagery. Theoretical radiances are computed at the 3.7, 10.7 and 11.8 μm infrared spectral bands of the AVHRR as a function of cloud top altitude and cloud amount for a range of cloud conditions. Satellite-measured radiances are then compared to the theoretical values at each wavelength to determine the best cloud height/cloud amount match for a pixel. Test case comparisons using manually selected clear and parti...

Abstract: Layer cloud amounts for the months of January and July 1979 have been extracted from a compressed version of the U.S. Air Force's 3D-nephanalysis. These layer cloud amounts are discussed in the context of the total cloud amount climatology described by Hughes and Henderson-Sellers. Low cloud (≲2000 m) is the predominant cloud type in most regions. High cloud (≳6000 m) amounts are generally less than ∼10% and amounts are significantly smaller than the cirrus cloud amounts of London. It seems likely that some high level cloud has been incorrectly archived as middle level cloud as a result of: (i) the assumption of cloud emissivities of one in the retrieval algorithm and (ii) the latitudinally-invarient definition of the middle/high cloud boundary. There is a reasonable level of agreement between zonally averaged low level and total cloud amounts derived here and those of London. West coast stratus is correctly identified as low cloud but the polar cloud amounts exhibit a seasonal cycle opposite to ...

Abstract: A technique is described by which the spacing of cloud particles can be measured using existing data from a cloud particle measurement probe. The monitor circuit used in this application is inexpensive and easy to build and connects easily to data systems already interfaced to particle measuring probes. Preliminary results show excellent agreement between predicted and measured spatial distributions of cloud droplets in adiabatic cloud regions but not always in mixed cloud regions on 10-m scales. This technique promise to be a valuable tool for the investigation of entrainment and other small-scale cloud microphysical processes.

Abstract: The urban fringe area is often characterized by a conflict between competing demands for land from many types of development; thus it requires active planning to achieve a landscape compatible with green-belt designation. Data were obtained from the NRSC SPOT-simulation campaign for an area near eastern Glasgow in an exercise to assess the value of remotely sensed data for surveying the structure of this urban fringe area. Digital enhancement and classification methods were applied to the data, identifying eight rural and six urban land-cover classes. Cloud and cloud shadow prevented a statistical accuracy assessment being performed. The most useful results were obtained by first stratifying the area into urban and rural subdivisions, followed by an interactive classification approach to the training and classification of desired fringe classes involving an analyst with local knowledge. Results showed that important urbanfringe classes of land cover can be readily identified from SPOT data, but t...

Abstract: The paper describes an automated technique for cloud motion vector extraction from INSAT -ID on visible and infra-red imagery over the oceanic areas around the Indian Peninsula. The technique is based on a pattern matching procedure which attempts to search for a pixel-to-pixel eqality between two grey shade distributions instead of cross-correlation. The CMVs are found to be very useful m augmenting the wind data over the oceanic areas and are consistent with each other and neighbouring radiosonde winds. The paper also discusses the sources of errors and uncertainties caused by the VHRR resolution and the wind derivation procedure.

Abstract: A hot-wire for use in laboratory clouds is presented The instrument is light, robust and easy to construct Tests were performed in a cloud and when the probe is operated at a wire temperature of 76 degrees C has an accuracy of 4% for a liquid water content of 10 g m-3

Abstract: The laser cloud mapper is a rapidly scanning laser radar system for transmission and concentration mapping of aerosol clouds in 3-dimensions and real-time dynamic information. It has been applied to the evaluation of IR screening clouds, forestry spraying and rarified aerosols.

Abstract: : The aims of our study as outlined in our original proposal were the following: (1) Carry out an initial study of suitably chosen LANDSAT data over both land and sea; (2) Develop the first step in the evolution of semi-automatic computer algorithms to obtain cloud morphology data on a global and long-term basis; (3) Provide a basis for future coordinated satellite, air and ground-based experiments on cloud field properties (4) Test and improve the modelling of cloud field optical properties for various purpose; (5) Use the data for testing models of atmospheric dynamics on various scales and to develop methods for using cloud morphology data as diagnostics for large scale atmospheric characteristics These aims have been carried out for the most part

Abstract: A method of cloud removal is presented utilizing data in the visible and near-infrared bands (0.5-1.1 μm) from a pair of HCMM (Heat Capacity Mapping Mission) satellite images of the South Island of New Zealand. The method uses two registered images, acquired at different times with different cloud distributions. The major improvement over other cloud detection techniques is the simultaneous use of a dual threshold to produce better cloud removal in the resulting mosaic picture from each original image. A previously developed mosaic method used by the EPIC image processing system at the Division of Information Technology, Department of Scientific and Industrial Research, New Zealand, to remove cloud is also used for comparison. The results show that both methods can be used to remove cloud but the appropriate method depends on the purpose of cloud removal.

Abstract: Some issues that arise in relation to the assimilation of cloud condensational heating in mesoscale prediction models are considered from a theoretical standpoint. A study is undertaken of the response of a simple atmospheric flow model to various forms of externally prescribed, mesoscale, steady, zero horizontally or area-averaged diabatic heating distributions. It is shown that the amplitude and/or phase of the response exhibits strong sensitivity to the depth of the \"cloud\" layer and to the shape of the vertical diabatic profile within the layer. On the premise that sustenance of the cloud system requires a phase match between the low-level convergence and the diabatic heating rate a search is made for forms of vertical diabatic profiles that satisfy this criterion. The results gleaned from this inverse approach are consistent with contentions that the contribution of evaporative cooling in a sub-cloud layer plays an important role in determining the response of \"shallow\" systems, and that the relative disposition of condensational heating between the upper and lower regions of the cloud layer is an important factor for \"deep\" systems. The general applicability of these inferences is limited by the idealised nature of the theoretical model employed in the study. At the very least, they serve as tentative, cautionary remarks on the issue of the assimilation of condensational heating effects in NWP models.

Abstract: PURPOSE:To prevent a windshield from clouding without fail as well as to secure its sightability in time of driving, by making a cloud eliminating device so as to be kept in an operating state unless an engine is stopped at a time when a cloud on the windshield is once detected during engine operation. CONSTITUTION:A cloud detecting device (humidity sensor) 1, emitting an electric signal corresponding to a moisture quantity contained in air inside a car room, is et up in the vicinity of an object windowplane (rear glass) surface. In addition, there is provided with a driving state detecting device 2 which takes out the electric signal as interlocked when an engine is made on or off by making a key switch of a car, and the output signal is inputted into a control device 3 together with a cloud detecting signal. And, while the electric signal showing that the engine is in operation is being inputted, a refrigerating cycle device is operated when the electric signal, showing a cloud generating state, is once inputted from the cloud detecting device 1, whereby a cloud eliminator 4 eliminating the cloud is controlled so as to be operated.

Abstract: The major accomplishment was the successful development of a method for extracting time derivative information from geostationary meteorological satellite imagery. This research is a proof-of-concept study which demonstrates the feasibility of using pattern recognition techniques and a statistical cloud classification method to estimate time rate of change of large-scale meteorological fields from remote sensing data. The cloud classification methodology is based on typical shape function analysis of parameter sets characterizing the cloud fields. The three specific technical objectives, all of which were successfully achieved, are as follows: develop and test a cloud classification technique based on pattern recognition methods, suitable for the analysis of visible and infrared geostationary satellite VISSR imagery; develop and test a methodology for intercomparing successive images using the cloud classification technique, so as to obtain estimates of the time rate of change of meteorological fields; and implement this technique in a testbed system incorporating an interactive graphics terminal to determine the feasibility of extracting time derivative information suitable for comparison with numerical weather prediction products.

Abstract: In order to make an unbiased survey for high-velocity gas in a single molecular cloud, a sensitive and uniformly sampled map of CO (J = 1-0) emission over a large fraction of the Mon OB1 (NGC 2264) molecular cloud was obtained. High-velocity line wings were detected on profiles over about 10 percent of the region surveyed. Complete maps of the 12, 25, 60 and 100-micron far-infrared emission from the Mon OB1 cloud were constructed as well by coadding the appropriate IRAS survey fields.

Abstract: A molecular cloud model that simulates the radiative transfer of the line emissions of a molecular gas is presented, together with methods for calculating the radiative transfer and line intensities in a clumpy medium. Observations of the Orion A cloud were used to study the model. To allow for a more complete distribution of molecular matter than hitherto considered, a new parameter, the volume-filling factor, is introduced. The results indicate that in order to observe the hot core of a cloud in the optically thick CO lines in a molecular gas that is not moving in a systematic way, the volume-filling factor needs to be very small at the cloud surface and increasingly large toward the center. 21 references.