Evidence for asymmetric inertial instability in the FIRE satellite dataset

One of the main goals of the First ISCCP Regional Experiment (FIRE) is obtaining the basic knowledge to better interpret satellite image of clouds on regional and smaller scales. An analysis of a mesoscale circulation phenomenon as observed in hourly FIRE satellite images is presented. Specifically, the phenomenon of interest appeared on satellite images as a group of propagating cloud wavelets located on the edge of a cirrus canopy on the anticylonic side of a strong, upper-level subtropical jet. These wavelets, which were observed between 1300 and 2200 GMT on 25 February 1987, are seen most distinctly in the GOES-West infrared satellite picture at 1800 GMT. The purpose is to document that these wavelets were a manifestation of asymmetric inertial instability. During their lifetime, the wavelets were located over the North American synoptic sounding network, so that the meteorological conditions surrounding their occurrence could be examined. A particular emphasis of the analysis is on the jet streak in which the wavelets were imbedded. The characteristics of the wavelets are examined using hourly satellite imagery. The hypothesis that inertial instability is the dynamical mechanism responsible for generating the observed cloud wavelets was examined. To further substantiate this contention, the observed characteristics of the wavelets are compared to, and found to be consistent with, a theoretical model of inertia instability by Stevens and Ciesielski

Linear and nonlinear aspects of the tropical 30-60 day oscillation: A modeling study

The scientific problem focused on study of the tropical 30-60 day oscillation and explanation for this phenomenon is discussed. The following subject areas are covered: the scientific problem (the importance of low frequency oscillations; suggested mechanisms for developing the tropical 30-60 day oscillation); proposed research and its objective; basic approach to research; and results (satellite data analysis and retrieval development; thermodynamic model of the oscillation; the 5-level GCM)

On symmetric stability and instability of zonal mean flows near the equator

September 1982.Includes bibliographical references

Global model of linearized atmospheric perturbations, A: model description

Includes bibliographical references

Sensitivity of the Walker Circulation to different basic states in a linear model, The

December, 1984.Includes bibliographical references.Sponsored by the National Science Foundation ATM-8305759

Global model of linearized atmospheric perturbations: revisions and improvements to original model

June 1989.Includes bibliographical references.Subsequent to the original description of our linearized primitive equation model, several improvements to its original design and corrections to its original description have been made. This manuscript represents a consolidation of these changes which include: Numerous corrections (typographic and otherwise); A provision for applying the horizontal boundaries at the poles. This document gives the form of these boundary conditions along with their derivation; An improved latitudinal finite differencing scheme in which the horizontal wind variables (u, v) are staggered mid way between thermodynamic variables. This new grid structure eliminates grid scale numerical noise in the results and has the added benefit of increasing computational efficiency by a factor of two; Treatment of the case where both the longitudinal wavenumber and frequency of the perturbation approach zero. In the original version of the model, considerable difficulty was encounter in computing a solution for this case.Sponsored by NSF grant ATM-8609731

Effect of horizontal pressure gradients on the momentum transport in tropical convective lines, The

December 1985.Includes bibliographical references.Sponsored by the National Science Foundation ATM-8305759

Global low order spectral model designed for climate sensitivity studies

March 1984.Includes bibliographical references.A two-level, global, spectral model using pressure as a vertical coordinate is developed. The system of equations describing the model is nonlinear and quasi-geostrophic (linear balance) (Lorenz, 1960). A moisture budget is calculated in the lower layer only with moist convective adjustment between the two layers. The mechanical forcing of topography is introduced as a lower boundary vertical velocity. Solar forcing is specified assuming a daily mean zenith angle. On land and sea ice surf aces a steady state thermal energy equation is solved to calculate the surface temperature. Over the oceans the sea surface temperatures are prescribed from the climatological average of January. The model is integrated to simulate the January climate.Sponsored by the Department of Energy grant DE-AS02-76EV01340; the National Aeronautics and Space Administration contract NAG 5-136; and the National Science Foundation grant ATM-80-16867

Migrating diurnal tide in the tropical troposphere: theory and observations compared, The

November, 1982.Includes bibliographical references.Sponsored by the National Science Foundation ATM-7826764.Sponsored by the National Science Foundation ATM-8107136

Comparison of two cumulus parameterization schemes in a linear model of wave-cisk, A

August, 1982.Includes bibliographical references.Sponsored by National Science Foundation ATM-8107136.Sponsored by the Office of Naval Research N00014-79-C-0793