NCAR Technical Notes

The NCAR Technical Notes Collection comprises over 500 scientific and technical reports, issued by NCAR divisions and programs, and consists of data compilations, theoretical and numerical investigations, and experimental results.


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Atlas of Simultaneous Occurrence of Different Cloud Types Over the Ocean
Atlas of Simultaneous Occurrence of Different Cloud Types Over the Ocean
This is the first atlas in a series of four atlases from a study of the global cloud distribution from ground-based observations. The International Satellite Cloud Climatology Project (ISCCP), a five-year project is now under way, will study the methods of obtaining cloud information from satellite radiation observations. This atlas of co-occurrence of different cloud types over the ocean is expected to aid in the development of these methods by providing ground-based data for comparison with satellite observations. It should also assist the development of cloud generation schemes in climate models. The frequency of occurrence of each cloud type and the co-occurrence of different types are described, but no information about cloud amounts are included.
Atlas of the Global Distribution of Total Ozone July 1957 - June 1967
Atlas of the Global Distribution of Total Ozone July 1957 - June 1967
This Atlas has been prepared to provide meteorologists, chemists, biologists, dermatologists and others with useful information on the global ozone distribution and its variations. The ten-year period covered by the Atlas was taken to start in July 1957 when the number of ozone observing stations increased significantly as part of the program for the International Geophysical Year (IGY). Although this Atlas is based on a relatively meager climatological network, the data set used here represents about 90% of all total ozone observations made through June 1967.
Balloon Film Performance After Prior Stress
Balloon Film Performance After Prior Stress
This report describes a series of tests conducted on balloon film material to determine if uneven loading of the balloon film material might cause failure at a stress level lower than the originally designated ultimate strength of the material. Specimens of polyethylene balloon film from two different manufacturers were tested to learn the effects of prior loading on the ultimate strength of the material. Different film thicknesses were tested uniaxially at the temperature environments most representative of balloon flight conditions, +25 and -80��C, and biaxially at +25��C.
Balloon Shapes and Stresses Below the Design Altitude
Balloon Shapes and Stresses Below the Design Altitude
Design data for natural-shape balloons, published in 1952, have been used to design thousands of balloons. These data, however, describe the balloon only at its float altitude. Most balloon failures occur during ascent, indicating that stress on the balloon is greater during ascent than under float conditions. This report presents a study conducted to provide information needed to understand the stresses in ascending balloons.
Balloon Strain Relief System
Balloon Strain Relief System
A balloon strain relief system for use during pre-launch activities was developed and its effect on balloon tensile strength was examined. Various clamp materials and balloons and tensile test specimens from the balloons were laboratory tested. This restraint system was deemed feasible if a limited localized loss in film tensile strength could be tolerated.
Balloon Stress-Band Analysis
Balloon Stress-Band Analysis
A test program to photograph tropopause-level balloon ascent failures unexpectedly revealed the presence of a circumferential stress band in certain balloons which failed catastrophically in flight. This document concludes that modification or elimination of the stress band in balloon designs could prevent failure.
Ballooning Support for Cosmic-Ray Experiments: Joint United States - India International Quiet Sun Year Equatorial Expedition 6 March - 9 April 1965
Ballooning Support for Cosmic-Ray Experiments: Joint United States - India International Quiet Sun Year Equatorial Expedition 6 March - 9 April 1965
NCAR organized and provided program management for a balloon expedition to study cosmic rays in the vicinity of the equator during the International Quiet Sun Year (IQSY). The program was conducted as a joint United States - India activity in Hyderabad, India. This document reports the ballooning support provided for these balloon-borne cosmic-ray experiments to participants in the program and to others interested in balloon-borne experiments.
Batch Computing on the CRAY-1
Batch Computing on the CRAY-1
This report defines and guides the user through various processes on the CRAY-1 computer.
Beyond Machoflops: Getting MPPs Into the Production Environment
Beyond Machoflops: Getting MPPs Into the Production Environment
In the continuing pursuit of the highest performance, many parallel computer manufacturers are trying to harness the promise of "killer micros" to deliver higher and higher computational rates to supercomputer users. The emphasis is on reducing clock cycles, improving hardware architectures, and increasing the number of floating point operations per second a system can deliver on benchmarks and kernels. However, there is more to a computer system than hardware. What has been lost in this pursuit is the same emphasis on providing the software that makes such systems both usable and manageable. The software fabric (libraries, utilities, programming environment, etc.) is no less important than the underlying hardware. This software aspect of a computer system is important at NCAR and many other research organizations because there are many more scientists that compute than computer scientists. A robust software environment has a tremendous impact on the ease of developing, debugging, and optimizing large codes as well as the ability to administrate such a system. Here we detail a "Top 10 List" of requirements necessary to successfully integrate massively parallel processing systems into a production computing environment, a domain currently dominated by vector supercomputers.
Bias-Corrected CMIP5 CESM Data in WRF/MPAS Intermediate File Format
Bias-Corrected CMIP5 CESM Data in WRF/MPAS Intermediate File Format
This technical note describes the generation of global bias corrected climate model output files from version 1 of NCAR's Community Earth System Model (CESM; Hurrell et al. 2013) that participated in phase 5 of the Coupled Model Intercomparison Experiment (CMIP5), which supported the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). The dataset contains all the variables needed for the initial and boundary conditions for simulations with the Weather Research and Forecasting model (WRF; Skamarock et al. 2008) or the Model for Prediction Across Scales (MPAS; Ringler et al. 2008, Thuburn et al. 2009, and Skamarock et al. 2012), provided in the Intermediate File Format specific to WRF and MPAS. The data are interpolated to 26 pressure levels, have a horizontal resolution of approximately 1°, and are provided in files at six hourly intervals. The variables have been bias corrected using the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim; Simmons et al. 2006 and Dee et al. 2011) fields for 1981-2005, following the method in Bruyère et al. (2014). Files are available for a 20th Century simulation (1951-2005) and three concomitant Representative Concentration Pathway (RCP) future scenarios (RCP4.5, RCP6.0 and RCP8.5) spanning 2006-2100, and are freely available from Monaghan et al. (2014).
Biosphere-atmosphere Transfer Scheme (BATS) Version 1e as Coupled to the NCAR Community Climate Model
Biosphere-atmosphere Transfer Scheme (BATS) Version 1e as Coupled to the NCAR Community Climate Model
This report describes the physical processes, current numerical parameterizations, and some of the code structure of BATSle. BATSle, a piece of software, that runs as an offline version or coupled to CCM. It includes (i) assignment of land type and soil information to each model grid square, (ii) calculation of soil, snow or sea-ice surface temperature in response to net surface heating and depending on soil or snow heat capacity and thermal conductivity, (iii) calculation of soil moisture, evaporation, and surface and groundwater runoff, (iv) specification of vegetation cover in terms of fractional ground shading and relative areas of transpiring and nontranspiring plant surfaces for different types of land-use, (v) surface albedo in terms of soil moisture, vegetation cover, and snow cover, including the shading of snow by vegetation, (vi) plant water ,budget including foliage and stem water storage, intercepted precipitation, and transpiration as limited by stomatal resistance and soil dryness, (vii) surface drag coefficients as a function of bulk Richardson number and vegetation cover, and (viii) determination of foliage temperature in response to energy-balance requirements and consequent fluxes of heat and moisture from the foliage to canopy air.

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