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Ramamurthy, Mohan K.; Rauber, Robert M.; Collins, Brian P.; Shields, Michael T.; Kennedy, Patrick C.; Clark, Wallace L.
doi: 10.1175/1520-0477(1991)072<0764:UAUOIF>2.0.CO;2pmid: N/A
To obtain a better understanding of the role of synoptic-scale disturbances in organizing mesoscale precipitation in the midwestern United States during the winter season, and to address scientific issues regarding mesoscale dynamics of winter storms, the University of Illinois Winter Precipitation Program was conducted over a period of three winters between 1988 and 1990. The observing systems included a 10-cm wavelength meteorological Doppler radar operated by the Illinois State Water Survey, the Flatland 6-m wind profiler operated by the NOAA Aeronomy Laboratory, and an NCAR Cross-chain Loran Atmospheric Sounding System. In all, 26 storms were observed during the 3-year period. The associated precipitation ranged from highly convective storms in the warm sector to stratified clouds containing organized banded structure within the occlusion. The principle dynamical mechanisms at work often varied widely from one storm to another and sometimes within a storm. This article describes the goals and objectives of the project, as well as a few selected observations and some preliminary findings from the data gathered.
Kingwell, Jeff; Shimizu, Junichiro; Narita, Kaneaki; Kawabata, Hirofumi; Shimizu, Itsuro
doi: 10.1175/1520-0477(1991)072<0778:WFAROA>2.0.CO;2pmid: N/A
Many of the techniques employed for rocket meteorologyrocket-castinghave been adapted from aviation. However, the unique characteristics and requirements of rocketry demand special meteorological procedures and instrumentation, which are only recently becoming satisfactorily defined.The influence of weather parameters on operational rocketry is examined, with special emphasis on the Tanegashima Space Center, Japan. It is concluded that the fundamental requirement for efficient launch operations is a highly sophisticated nowcasting facility, backed by an effective research and development program.On 13 August 1986, the National Space Development Agency of Japan (NASDA) launched from the Osaki rocket range in Tanegashima three payloads on the inaugural flight of the H-1 launch vehicle.The launch weather was expected to be fine at the range. In the event, a thunderstorm commenced close to the launch area during the last few seconds before launch, which nevertheless proceeded successfully. This incident highlights the uncertainties of rocket operations, particularly in the critical area of the provision of reliable weather information and forecasts.The synoptic conditions at the time of the 13 August launch incident are examined, and a qualitative forecast checklist is suggested to assist in forecasting similar summertime early-morning maritime storms in the future.
doi: 10.1175/1520-0477(1991)072<0795:TREOCA>2.0.CO;2pmid: N/A
Our knowledge of the direct role of clouds in long-term climate change is examined in an overview of key results published over the last 15 or 20 years, along with some relevant unpublished model studies. The focus is on 1) the impact of clouds on the incoming and outgoing radiation at the top of the atmosphere, and 2) the two-way interaction of clouds with other variables of the climate systemi.e., the cloud/climate feedback problemas revealed by climate model simulations. A common framework is established for comparing results from different investigations.The total effect of clouds on radiative fluxes at the top of the atmospherespecifically, the difference in flux between average conditions and cloud-free conditions, often called cloud forcinghas been derived from earth radiation budget measurements by several investigators using various data sources and methods. There is general agreement that the annual global mean effect of clouds is to cool the climate system, but there is significant disagreement on magnitude, with the two' investigations based on recent satellite data indicating a range from 17 to 27 W/m2.Cloud sensitivity, which represents the differential response of top-of-the-atmosphere fluxes to changes in cloud cover parameters, is a critical factor in cloud feedback. The observational data at this point in time, however, are not sufficient to yield more than rough estimates. Two estimates, of the sensitivity to cloud amount, show wide discrepancies. To be useful, future studies of sensitivity will have to separate different cloud types.Sensitivity of clouds to cloud condensation nuclei raises the issue of a more direct role of clouds in climate change, where aerosols associated with S02 emissions can ultimately lead to brighter clouds and a reduction in solar heating.On cloud feedback in climate simulations, there are wide discrepancies amongst models. Investigators find, in general, that the sign of cloud feedback is positive when one allows the spatial distribution of clouds to vary in response to climate change. When one additionally takes into account the effect of changes in cloud properties, that result is less certain. The conclusion is: 1) clouds may have a strong influence on climate change, but 2) we are far from knowing the magnitude, and even the sign, of this influence.
doi: 10.1175/1520-0477-72.6.815pmid: N/A
Meteorological and oceanographic education in observational techniques and the relationship to national facilities' needs are reviewed. The significance of measurement science and its relationship to national capabilities are examined. Opportunities for the enhancement of national capabilities related to the application of measurement science to meteorology and oceanography are identified and recommendations for action are presented.
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