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WARREN R. KING

Abstract

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W. D. King
and
R. J. Handsworth

Abstract

It is shown that when liquid water contents are measured with the CSIRO hot-wire element, and cloud transmission measured in the UV with a simple optical system, then the two measurements can be combined to yield total droplet concentrations and average droplet size. Sizes and concentrations obtained from this technique are compared with those from an optical scattering probe, and reasonable agreement is found.

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Mu-King Tsay
,
Ting-I. Wang
,
R. S. Lawrence
,
G. R. Ochs
, and
R. B. Fritz

Abstract

In a cooperative field study of the planetary boundary layer, three optical wind sensors were placed around a 300 m meteorological tower in a 450 m equilateral triangle 3–4 m above the terrain. It was found that the convergence measured by the three-sensor system correlates well with in situ measurements of vertical wind by anemometers located on the tower at heights up to 300 m during the occurrence of thermal plumes. By analyzing the correlation between the optically measured convergence and the vertical wind measurements made on the tower, the inversion layer, if below the top of the tower, can usually be located in the early morning when thermal plumes are active. The space-averaged horizontal wind vectors measured by the optical system have good, though not perfect, agreement with the tower measurements at the lowest layer (10 m above the ground), and with the measurements of a nearby network of surface anemometers. A comparison of the optically measured convergence with the direction of the surface horizontal wind indicates some effect of irregular terrain.

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Phillip King
,
Lan R. McKinnon
,
John G. Mathieson
, and
Ivan R. Wilson

Abstract

The solar infrared spectra of Murcray et al. (1969) do not contain direct evidence for the presence of N2O5 in the stratosphere. Comparison of atmospheric and laboratory spectra indicate that the upper limit to stratospheric N2O5 number density is about 2 × 108 cm−3.

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Melinda L. King
,
Phillip J. Smith
, and
Anthony R. Lupo

Abstract

This paper examines the 48-h life cycle of a winter anticyclone occurring over North America from 18 to 20 January 1979 using Goddard Laboratory for Atmospheres FGGE level IIIb (SOP 1) global analyses on a 4° latitude by 5° longitude grid. Applying the relatively new methodology of the Zwack–Okossi equation, results show that anticyclonic vorticity advection and cold-air advection acted to develop the anticyclone, while adiabatic warming in the descending air opposed development. Other forcing processes made only small contributions to anticyclone changes. Vertical profiles of the development quantities reveal that vorticity and temperature advections, as well as the adiabatic warming, maximized in the 200–300-mb layer.

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W. D. King
,
D. A. Parkin
, and
R. J. Handsworth

Abstract

A liquid water sensor consisting of a thin copper wire wound on a hollow 1.5 mm diameter cylinder is described. Slave coils on either side of the master sensing coil reduce axial heat losses to an acceptable level, and allow for a simple relationship between power supplied to the wire and liquid water content. Wet wind-tunnel tests show that the system response to liquid water is easily calculable from a knowledge of the geometrical dimensions of the cylinder and the operating temperature of the hot wire. When operated at 100°C, the device has a sensitivity of 0.02 g m−3, a response time of better than 0.05 s and an accuracy of 5% at 1 g m−3.

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John J. Cassano
,
Thomas R. Parish
, and
John C. King

Abstract

Calculated surface fluxes from seven surface layer parameterizations are verified against 45 months of observations from Halley, Antarctica, with a temporal resolution of 1 h. The surface layer parameterizations are taken from widely used numerical models including the National Center for Atmospheric Research (NCAR) Community Climate models CCM2 and CCM3, the U.K. Met. Office Unified Climate Model, and the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). The observations include measurements of the mean wind speed and temperature inversion strength and direct measurements of the turbulent fluxes of heat and momentum.

A comparison of the calculated and observed fluxes is conducted for conditions in which the surface layer is stably stratified. Based on these comparisons it is found that the simulated friction velocity values are adequate (although slightly larger than the observed turbulent fluxes) under all but the highest bulk Richardson number conditions (greatest static stability). In contrast the magnitude of the calculated sensible heat flux is frequently less than that of the observed sensible heat flux. The use of a larger scalar roughness length for heat compared to that for momentum is found to remove this bias in the calculated sensible heat fluxes.

The correlation between the observed and calculated fluxes of heat and momentum is acceptable for the lower bulk Richardson number regimes, but is near zero for the high bulk Richardson number regime. The correlation between the calculated and observed fluxes is in general better for the momentum flux than for the sensible heat flux.

The bias in the calculated sensible heat flux could have significant implications for numerical simulations in which the flow is driven by surface processes, and may pose problems for climate-scale simulations. The impact that errors of the observed magnitude have on simulated katabatic winds is explored with a series of two-dimensional numerical simulations using MM5. Inferences about the relevance of these findings for climate simulations are also addressed.

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R. J. Taylor
,
S. T. Evans
,
N. K. King
,
E. T. Stephens
,
D. R. Packham
, and
R. G. Vines

Abstract

Convection in the air above an intense fire in northern Australia has been studied, and the results are compared with those of an earlier investigation.

At the height of the fire a short-lived condensation cloud, covering little more than 10% of the total fire area, rose to almost 6000 m above ground level. It is suggested that the rising column acted effectively as a barrier to the wind, so reducing mixing with the surrounding air and allowing convection to proceed very rapidly by the release of latent heat alone. In the earlier study it is likely that similar behavior occurred, but the effect was less marked.

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Clio Michel
,
Camille Li
,
Isla R. Simpson
,
Ingo Bethke
,
Martin P. King
, and
Stefan Sobolowski

Abstract

El Niño–Southern Oscillation (ENSO) is a main driver of climate variability worldwide, but the presence of atmospheric internal variability makes accurate assessments of its atmospheric teleconnections a challenge. Here, we use a multimodel large ensemble of simulations to investigate the ENSO teleconnection response to a low global warming scenario that represents Paris Agreement targets. The ensemble comprises five atmospheric general circulation models with two experiments (present-day and +2°C) in which the same set of ENSO events is prescribed, which allows for quantification of the uncertainty in the ENSO response due to internal variability. In winter, the teleconnection during the positive ENSO phase features a strong negative anomaly in sea level pressure over the northeast Pacific (and vice versa for the negative phase); this anomaly shifts northeastward and strengthens in the warming experiment ensemble. At least 50–75 ENSO events are required to detect a significant shift or strengthening, emphasizing the need to adequately sample the internal variability to isolate the forced response of the ENSO teleconnection under a low warming scenario. Even more events may be needed if one includes other sources of uncertainty not considered in our experimental setup, such as changes in ENSO itself. Over North America, precipitation changes are generally more robust than temperature changes for the regions considered, despite large internal variability, and are shaped primarily by changes in atmospheric circulation. These results suggest that the observational period is likely too short for assessing changes in the ENSO teleconnection under Paris Agreement warming targets.

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Michael D. King
,
Maxwell G. Strange
,
Peter Leone
, and
Lamdin R. Blaine

Abstract

A multi-wavelength scanning radiometer has been developed for measuring the angular distribution of scattered radiation deep within a cloud layer. The purpose of the instrument is to provide measurements from which the single scattering albedo of clouds can be derived as a function of wavelength. The radiometer has a 1° field of view and scans in the vertical plane from 5° before zenith to 5° past nadir (190° aperture). The thirteen channels of the cloud absorption radiometer are located between 0.5 and 2.3 μn and were selected to avoid the molecular absorption bands in the near-infrared. The first seven channels of the radiometer are simultaneously and continuously sampled, while the eighth registered channel is selected from among the six channels on a filter wheel. This paper describes the optical, mechanical and electrical design of the instrument and presents some early results obtained from measurements taken aboard the University of Washington's B-23 aircraft to illustrate the performance of the instrument.

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