Air temperature and two-dimensional wind profiles in the lowest 32 meters as a function of bulk stability

Author(s):  
H. Lettau ◽  
A. Riordan ◽  
M. Kuhn
2007 ◽  
Vol 20 (10) ◽  
pp. 2307-2314 ◽  
Author(s):  
K. J. E. Walsh ◽  
M. Fiorino ◽  
C. W. Landsea ◽  
K. L. McInnes

Abstract Objectively derived resolution-dependent criteria are defined for the detection of tropical cyclones in model simulations and observationally based analyses. These criteria are derived from the wind profiles of observed tropical cyclones, averaged at various resolutions. Both an analytical wind profile model and two-dimensional observed wind analyses are used. The results show that the threshold wind speed of an observed tropical cyclone varies roughly linearly with resolution. The criteria derived here are compared to the numerous different criteria previously employed in climate model simulations. The resulting method provides a simple means of comparing climate model simulations and reanalyses.


2005 ◽  
Vol 133 (9) ◽  
pp. 2669-2691 ◽  
Author(s):  
Richard P. James ◽  
J. Michael Fritsch ◽  
Paul M. Markowski

Abstract The organizational mode of quasi-linear convective systems often falls within a spectrum of modes described by a line of discrete cells on one end (“cellular”) and an unbroken two-dimensional swath of ascent on the other (“slabular”). Convective events exhibiting distinctly cellular or slabular characteristics over the continental United States were compiled, and composite soundings of the respective inflow environments were constructed. The most notable difference between the environments of slabs and cells occurred in the wind profiles; lines organized as slabs existed in much stronger low-level line-relative inflow and stronger low-level shear. A compressible model with high resolution (Δx = 500 m) was used to investigate the effects of varying environmental conditions on the nature of the convective overturning. The numerical results show that highly cellular convective lines are favored when the environmental conditions and initiation procedure allow the convectively generated cold pools to remain separate from one another. The transition to a continuous along-line cold pool and gust front leads to the generation of a more “solid” line of convection, as dynamic pressure forcing above the downshear edge of the cold outflow creates a swath of quasi-two-dimensional ascent. Using both full-physics simulations and a simplified cold-pool model, it is demonstrated that the magnitude of the two-dimensional ascent in slabular convective systems is closely related to the integrated cold-pool strength. It is concluded that slabular organization tends to occur under conditions that favor the development of a strong, contiguous cold pool. The tendency to produce slabular convection is therefore enhanced by environmental conditions such as large CAPE, weak convective inhibition, strong along-line winds, and moderately strong cross-line wind shear.


1986 ◽  
Vol 13 (2) ◽  
pp. 140-149 ◽  
Author(s):  
R. Frederking ◽  
E. Wessels ◽  
J. B. Maxwell ◽  
S. Prinsenberg ◽  
M. Sayed

As a continuation of an ongoing project, measurements of environmental conditions and ice cover responses were made around Adams Island over the winter of 1983/1984. These included current, tide, speed and direction of wind, air temperature, and thickness, temperature, and salinity of the ice. Wind profiles were measured over the ice surface; from these, drag coefficients of 0.001–0.005 were calculated. Horizontal movement rates of the ice cover varied from 20 to 300 mm/day. No direct correlation was found between ice cover movement and the wind and current measurements. In situ ice pressures measured around the island averaged 250 kPa. Key words: ice pressures, environmental forces, ice behaviour, field instrumentation.


1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.


1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.


1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.


2000 ◽  
Vol 179 ◽  
pp. 229-232
Author(s):  
Anita Joshi ◽  
Wahab Uddin

AbstractIn this paper we present complete two-dimensional measurements of the observed brightness of the 9th November 1990Hαflare, using a PDS microdensitometer scanner and image processing software MIDAS. The resulting isophotal contour maps, were used to describe morphological-cum-temporal behaviour of the flare and also the kernels of the flare. Correlation of theHαflare with SXR and MW radiations were also studied.


Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.


Author(s):  
B. Ralph ◽  
A.R. Jones

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.


Sign in / Sign up

Export Citation Format

Share Document