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R. K. Reed and W. P. Elliott

Abstract

The problems of using raingages on ships are discussed, and methods of estimating rainfall from weather reports at sea are reviewed, with emphasis on discussion of efforts to verify the assessments derived by Tucker (1961). A raingage was used on cruises of the NOAA ship Oceanographer in the eastern Pacific during 1975 and 1976, and rainfall was estimated from weather reports using Tucker's assessments. In extratropical latitudes (mainly 40–60°N), a catch of 35 cm was obtained; estimates from the weather reports gave a value of 31 cm. Thus Tucker's assessments are essentially in agreement with catches from a small gage in this region. In the tropics, however, the agreement was not good. Almost three times as much rain was caught as was estimated; hence Tucker's coefficients will need to be reevaluated for this area.

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P. J. Stabeno and R. K. Reed

Abstract

From 1986 through April 1993, 86 satellite-tracked buoys were deployed in the North Pacific and Bering Sea. Most of the buoys were drogued at 40 m. A composite current pattern is derived using these data. The two principal currents (the Alaskan Stream and Kamchatka Current) are clearly evident. Eddy kinetic-mean kinetic energy ratios are low in the stream and along the western Bering Sea basin. An eastward flowing current occurred along the north flank of the Aleutian Islands, this flow was modified by inflow at the passes. Westward flow occurred north of 56°N; its source was the Bering Slope Current. The Kamchatka Current originated near 175°E along the Russian coast. Numerous eddies and meanders were observed in the Kamchatka Current; eddies were also present on the eastern side of the basin.

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W. P. Elliott and R. K. Reed

Abstract

Climatological estimates of mean annual precipitation over the world ocean are presented and discussed. We obtained a value for mean annual oceanic precipitation (between 65°N and 60°S) of 93 cm, which is smaller than some other estimates. These results are supported by a recent analysis of tropical rainfall based on satellite techniques. Aspects of the need for and utility of climatological information are discussed.

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Reed P. Timmer and Peter J. Lamb

Abstract

The increased U.S. natural gas price volatility since the mid-to-late-1980s deregulation generally is attributed to the deregulated market being more sensitive to temperature-related residential demand. This study therefore quantifies relations between winter (November–February; December–February) temperature and residential gas consumption for the United States east of the Rocky Mountains for 1989–2000, by region and on monthly and seasonal time scales. State-level monthly gas consumption data are aggregated for nine multistate subregions of three Petroleum Administration for Defense Districts of the U.S. Department of Energy. Two temperature indices [days below percentile (DBP) and heating degree-days (HDD)] are developed using the Richman–Lamb fine-resolution (∼1° latitude–longitude) set of daily maximum and minimum temperatures for 1949–2000. Temperature parameters/values that maximize DBP/HDD correlations with gas consumption are identified. Maximum DBP and HDD correlations with gas consumption consistently are largest in the Great Lakes–Ohio Valley region on both monthly (from +0.89 to +0.91) and seasonal (from +0.93 to +0.97) time scales, for which they are based on daily maximum temperature. Such correlations are markedly lower on both time scales (from +0.62 to +0.80) in New England, where gas is less important than heating oil, and on the monthly scale (from +0.55 to +0.75) across the South because of low January correlations. For the South, maximum correlations are for daily DBP and HDD indices based on mean or minimum temperature. The percentiles having the highest DBP index correlations with gas consumption are slightly higher for northern regions than across the South. This is because lower (higher) relative (absolute) temperature thresholds are reached in warmer regions before home heating occurs. However, these optimum percentiles for all regions are bordered broadly by surrounding percentiles for which the correlations are almost as high as the maximum. This consistency establishes the robustness of the temperature–gas consumption relations obtained. The reference temperatures giving the highest HDD correlations with gas consumption are lower for the colder northern regions than farther south where the temperature range is truncated. However, all HDD reference temperatures greater than +10°C (+15°C) yield similar such correlations for northern (southern) regions, further confirming the robustness of the findings. This robustness, coupled with the very high correlation magnitudes obtained, suggests that potentially strong gas consumption predictability would follow from accurate seasonal temperature forecasts.

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Todd P. Lane and Michael J. Reeder

Abstract

This study uses a two-dimensional cloud-resolving model to examine how convectively generated gravity waves modify the environment of an isolated convective cloud. The model is initialized with an idealized sounding, and the cloud is initiated by adding a locally buoyant perturbation. The modeled convection generates a spectrum of gravity waves with vertical wavelengths that are harmonics of the depth of the troposphere. It is shown that the first three wave modes significantly modify the cloud environment.

The modification of the cloud environment is quantified in terms of the convective available potential energy (CAPE) and convective inhibition (CIN). The first two wave modes travel fastest away from the cloud and are responsible for the changes in CAPE, whereas the third wave mode causes low-level lifting and hence a reduction in CIN. The maximum far-field perturbations in CAPE and CIN are approximately 15% and 33% of the initial background values, respectively. These results agree with previous studies of more organized convection, predicting the existence of a region surrounding the convective system that favors the development of new convection.

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Ralph C. Reeder and T. P. Gleiter
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R. K. Reed, J. D. Schumacher, and J. P. Blaha

Abstract

A current record during February -August 1980 over the continental slope off Kodiak Island provided the first Eulerian measurements in the high-speed region of the Alaskan Stream. The net flow at 980 m during the 6-month period was 6 cm s−1 at 235°, but there were major low-frequency variations in the current. These appeared to result from the occasional advection of meanders past the mooring, however, rather than from features such as planetary waves. The ratio of fluctuating to mean kinetic energy was much lower than reported values in the Kuroshio and Gulf Stream, probably as a result of important kinematic differences in these flows.

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Todd P. Lane, Michael J. Reeder, and Terry L. Clark

Abstract

Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep convection over the Tiwi Islands, Australia. The numerical calculations presented explicitly resolve both the mesoscale convective cloud cluster and the gravity waves generated. As the convective clouds evolve, they excite gravity waves, which are prominent features of the model solutions in both the troposphere and stratosphere. The source location is variable in time and space but is related to the development of individual convective cells. The largest amplitude gravity waves are generated when the cloud tops reach the upper troposphere.

A new analysis technique is introduced in which the nonlinear terms in the governing equations are taken as the forcing for linear gravity waves. The analysis shows that in the present calculation, neither the shear nor the diabatic heating are the dominant forcing terms. Instead, the wave source is most easily understood when viewed in a frame of reference moving with the wind at the level of neutral buoyancy, whereupon the source may be described as a vertically oriented, oscillating convective updraft. This description is consistent with the properties of the modeled stratospheric waves.

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Capt. Kenneth P. Kidd, A.C. and Capt. Charles K. Reed, A.C.
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L. A. Mathews, D. W. Reed, P. St. Amand, and R. Stirton

Abstract

The time required for an ice nucleus of radius r A to dissolve in a water drop of radius r D is found for solubilities ranging from 5 × 10−10 (pure silver iodide at OC) to 10−3. The basic assumption is that the dissolution of the liquid-solid interface is rapid compared to the diffusion of solute from the interface to the bulk of the solution, and hence the latter controls the rate of solution. The calculations show that most ice nuclei smaller than 0.01 or 0.05 μ in radius will be dissolved within a period of a few seconds and in some cases within a fraction of a second.

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