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William R. Cotton

Bio: William R. Cotton is an academic researcher from Colorado State University. The author has contributed to research in topics: Mesoscale meteorology & Cloud condensation nuclei. The author has an hindex of 69, co-authored 257 publications receiving 18298 citations. Previous affiliations of William R. Cotton include Goddard Space Flight Center & Cooperative Institute for Research in the Atmosphere.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a range of applications of the Regional Atmospheric Modeling System (RAMS), a comprehensive mesoscale meterological modeling system, are discussed, including large eddy simulations (LES) and simulations of thunderstorms, cumulus fields, mesoscales, convective systems, mid-latitude cirrus clouds, winter storms, mechanically and thermally-forced meso-scale systems, and mesoscopic atmospheric disperision.
Abstract: This paper presents a range of applications of the Regional Atmospheric Modeling System (RAMS), a comprehensive mesoscale meterological modeling system. Applications discussed in this paper include large eddy simulations (LES) and simulations of thunderstorms, cumulus fields, mesoscale convective systems, mid-latitude cirrus clouds, winter storms, mechanically- and thermally-forced mesoscale systems, and mesoscale atmospheric disperision. A summary of current RAMS options is also presented. Improvements to RAMS currently underway include refinements to the cloud radiation, cloud microphysics, cumulus, and surface soil/vegetative parameterization schemes, the parallelization of the code, development of a more versatile visualization capability, and research into meso-α-scale cumulus parameterization.

1,685 citations

Journal ArticleDOI
TL;DR: An overview of the Regional Atmospheric Modeling System (RAMS) is presented in this paper, where the authors focus on new developments in the RAMS physics and computational algorithms since 1992 and summarize some of the recent applications of RAMS that includes synoptic-scale weather systems and climate studies, to small-scale research using RAMS configured as a large eddy simulation model or to even flow around urban buildings.
Abstract: ¶An overview of the Regional Atmospheric Modeling System (RAMS) is presented. We focus on new developments in the RAMS physics and computational algorithms since 1992. We also summarize some of the recent applications of RAMS that includes synoptic-scale weather systems and climate studies, to small-scale research using RAMS configured as a large eddy simulation model or to even flow around urban buildings. The applications include basic research on clouds, cloud systems, and storms, examination of interactions between tropical deep convective systems and ocean circulations, simulations of tropical cyclones, extreme precipitation estimation, regional climatic studies of the interactions between the atmosphere and the biosphere or snow-covered land-surfaces, prototype realtime mesoscale numerical weather prediction, air pollution applications, and airflow around buildings.

900 citations

Journal ArticleDOI
TL;DR: In this paper, a model combining the effects of deposition and condensation-freezing nucleation is formulated based on data obtained from continuous-flow diffusion chambers, which indicate an exponential variation of ice-nuclei concentrations with ice supersaturation reasonably independent of temperatures between −7° and −20°C.
Abstract: Two new primary ice-nucleation parameterizations are examined in the Regional Atmospheric Modeling System (RAMS) cloud model via sensitivity tests on a wintertime precipitation event in the Sierra Nevada region. A model combining the effects of deposition and condensation-freezing nucleation is formulated based on data obtained from continuous-flow diffusion chambers. The data indicate an exponential variation of ice-nuclei concentrations with ice supersaturation reasonably independent of temperatures between −7° and −20°C. Predicted ice concentrations from these measurements exceed values predicted by the widely used temperatures dependent Fletcher approximation by as much as one order of magnitude at temperatures warmer than −20°C. A contact-freezing nucleation model is also formulated based on laboratory data gathered by various authors using techniques that isolated this nucleation mode. Predicted contact nuclei concentrations based on the newer measurements are as much as three orders of mag...

842 citations

Journal ArticleDOI
TL;DR: In this article, a new cloud microphysical parameterization is described, which uses generalized gamma distributions as the basis function for all hydrometeor species, allowing heat storage and mixed phase hydrometers.

595 citations

Book
07 Sep 1992
TL;DR: In this paper, the authors present a method to find the most relevant information from the Bibliogr. Index Reference Record created on 2004-09-07, modified on 2016-08-08
Abstract: Note: Bibliogr. : p. 863-870. Index Reference Record created on 2004-09-07, modified on 2016-08-08

495 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors present an overview of the climate system and its dynamics, including observed climate variability and change, the carbon cycle, atmospheric chemistry and greenhouse gases, and their direct and indirect effects.
Abstract: Summary for policymakers Technical summary 1. The climate system - an overview 2. Observed climate variability and change 3. The carbon cycle and atmospheric CO2 4. Atmospheric chemistry and greenhouse gases 5. Aerosols, their direct and indirect effects 6. Radiative forcing of climate change 7. Physical climate processes and feedbacks 8. Model evaluation 9. Projections of future climate change 10. Regional climate simulation - evaluation and projections 11. Changes in sea level 12. Detection of climate change and attribution of causes 13. Climate scenario development 14. Advancing our understanding Glossary Index Appendix.

13,366 citations

DOI
01 Jan 2008
TL;DR: The Technical Note series provides an outlet for a variety of NCAR manuscripts that contribute in specialized ways to the body of scientific knowledge but which are not suitable for journal, monograph, or book publication.
Abstract: The Technical Note series provides an outlet for a variety of NCAR manuscripts that contribute in specialized ways to the body of scientific knowledge but which are not suitable for journal, monograph, or book publication. Reports in this series are issued by the NCAR Scientific Divisions ; copies may be obtained on request from the Publications Office of NCAR. Designation symbols for the series include: Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the National Science Foundation.

9,022 citations

Journal ArticleDOI
TL;DR: In this article, a revised vertical diffusion algorithm with a nonlocal turbulent mixing coefficient in the planetary boundary layer (PBL) is proposed for weather forecasting and climate prediction models, which improves several features compared with the Hong and Pan implementation.
Abstract: This paper proposes a revised vertical diffusion package with a nonlocal turbulent mixing coefficient in the planetary boundary layer (PBL). Based on the study of Noh et al. and accumulated results of the behavior of the Hong and Pan algorithm, a revised vertical diffusion algorithm that is suitable for weather forecasting and climate prediction models is developed. The major ingredient of the revision is the inclusion of an explicit treatment of entrainment processes at the top of the PBL. The new diffusion package is called the Yonsei University PBL (YSU PBL). In a one-dimensional offline test framework, the revised scheme is found to improve several features compared with the Hong and Pan implementation. The YSU PBL increases boundary layer mixing in the thermally induced free convection regime and decreases it in the mechanically induced forced convection regime, which alleviates the well-known problems in the Medium-Range Forecast (MRF) PBL. Excessive mixing in the mixed layer in the presenc...

5,363 citations

Journal ArticleDOI
TL;DR: Modifications to the Kain‐Fritsch convective parameterization evolved from an effort to produce desired effects in numerical weather prediction while also rendering the scheme more faithful to observations and cloud-resolving modeling studies.
Abstract: Numerous modifications to the Kain‐Fritsch convective parameterization have been implemented over the last decade. These modifications are described, and the motivating factors for the changes are discussed. Most changes were inspired by feedback from users of the scheme (primarily numerical modelers) and interpreters of the model output (mainly operational forecasters). The specific formulation of the modifications evolved from an effort to produce desired effects in numerical weather prediction while also rendering the scheme more faithful to observations and cloud-resolving modeling studies.

4,056 citations