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2.1 Pan-WCRP Monsoon Modelling Workshop Summary

Description: Ken Sperber led a discussion of the outcome of the Pan-WCRP Monsoon Modelling Workshop that was held at the University of California at Irvine from 15-17 June 2005. At the workshop presentations from key CLIVAR and GEWEX panels were presented to highlight the outstanding problems in modelling the Earth's monsoons. Additionally, presentations from invited experts were given to highlight important aspects of monsoon phenomena and processes, such as low-level jets, air-sea interaction, predictability, observational networks/studies, and model test beds etc. Since all persons attending the CLIVAR AAMP meeting were present for all, or most, of the monsoon workshop, a detailed description of the workshop presentations was not given. Rather, the discussion was focused on the recommendations of the workshop breakout groups and their relevance to CLIVAR AAMP. CLIVAR AAMP endorsed the near-term workshop recommendation of investigating the diurnal cycle using a hierarchy of models a key way forward for promoting CLIVAR/GEWEX interactions. In GCM studies CLIVAR researchers have identified the diurnal cycle as a forced ''mode'' of variability that is poorly represented in terms of amplitude and phase, especially in the case of precipitation. Typical phase errors of 6-12 hours are noted over both land and ocean in GCMs. CLIVAR views adequate simulation of the diurnal cycle as key aspect of variability in its own right, but also because of its potential rectification on to subseasonal variability (e.g., the Madden-Julian oscillation). It is hypothesized that improvement of diurnal variability may lead to an improved representation of intraseasonal variability and improved skill of monsoon forecasts on medium-range to seasonal time scales.
Date: June 28, 2005
Creator: Sperber, K R
Partner: UNT Libraries Government Documents Department

04 nuclear safety: pressure piping crack monitoring detection of metal overstress by acoustic emission. Progress report, July-September 1966

Description: The three main areas of effort have been: (1) definition of the general acoustic response pattern related to the gross aspects of forming and extending a crack in various materials, (2) development of a monitor system prototype concept exclusive of transducers and (3) development of a suitable, high temperature transducer. Tests using double cantilever beam (DCB) specimens of various materials to establish conditions of crack formation and growth have indicated that material ductility is a major controlling factor in the acoustic response pattern. It appears to effect both acoustic emission intensity and the point in the crack formation-growth sequence at which the main emission occurs. A concept has been developed for the prototype of a full scale monitor system. Hardware development is being limited to the analyzer portion of the system at this time because it is the part most significant to demonstrating feasibility of the intended application. Signal level and signal rate are both being investigated as possible parameters for evaluating acoustic emission data. Of the various transducers for potential high temperature application, the capacitive or electrostatic transducer now looks most promising. A significant improvement in sensitivity has been achieved and a trial model used during recent tests produced generally satisfactory data. The sequence of effort on the program is being adjusted somewhat from that previously outlined. Some of the more detailed investigative phases will receive only moderate attention, temporarily, in favor of first demonstrating the basic feasibility of detecting acoustic emission and making a meaningful analysis under postulated service conditions.
Date: October 28, 1966
Creator: Hutton, P H
Partner: UNT Libraries Government Documents Department