Ernest C. Kung

STUDY OF A CONTINENTAL SURFACE ALBEDO ON THE BASIS OF FLIGHT MEASUREMENTS AND STRUCTURE OF THE EARTH'S SURFACE COVER OVER NORTH AMERICA*

Abstract A series of 12 monthly flights along a fixed path in Wisconsin and a series of 4 long-range flights over extensive areas of the United States and Canada were performed during 1963 to measure systematically the surface albedo over various types of the earths surface, using an instrumented light airplane operating at a low level. An approximate total of 24,000 mi. was flown and roughly 210,000 sets of the measurements were processed for this study. Techniques of measurement and data treatment are discussed. It is shown, and discussed in detail, that the regional differences and seasonal variations of the surface albedo due to thc structure and state of the earths surface cover are significant. The snow cover is the most important modification of the earths surface, giving a significantly higher albedo. A quantitative relationship between the increase of surface albedo and snow cover is examined. The surface albedo measured during the flights over typical surface covers over North America, includ...

DIURNAL AND LONG-TERM VARIATIONS OF THE KINETIC ENERGY GENERATION AND DISSIPATION FOR A FIVE-YEAR PERIOD

Abstract The diurnal variation and long-term variation of the kinetic energy generation and dissipation are investigated with the wind and geopotential data observed twice a day at 00 and 12 gmt over North America during a 5-yr. period. The generation from the work done by the horizontal pressure force and the dissipation are significantly and consistently greater at 00 gmt than at 12 gmt. The diurnal variation is especially pronounced during the summer. The annual march of the seasons and the year-to-year variation of the kinetic energy parameters are also significant. By the use of twice-a-day observations for an extended period, the study over North America is increased in generality as an approximation to hemispherical features. However, some uncertainty remains in this respect because of the possible effects of the semidiurnal variations and unconfirmed radiation errors in the radiosonde observations. The previously reported double maxima of the generation and dissipation in the planetary boundary la...

Energetics Analysis of the Global Circulation during the Special Observation Periods of FGGE

Abstract A global energetics analysis is presented for the FGGE SOP-1 and SOP-2 with ECMWF and GFDL data sets. Both global integral properties and spectral characteristics are examined. There is a large discrepancy between the present FGGE analysis and previously available estimates concerning the level of available potential energy and kinetic energy. This discrepancy is attributable to an earlier restriction of data coverage. There is a significant seasonal difference in the energy reservoir of the Northern Hemisphere, whereas the difference is minor in the Southern Hemisphere. This leads to a seasonal contrast of the globally integrated energy budget which comes mostly from the Northern Hemisphere. Both the global energy level and the intensity of the general circulation are more pronounced during SOP-1 than during SOP-2. One major focus of attention in this study is an energetics comparison of ECMWF and GFDL data sets. There is a twofold difference in the intensity of the general circulation as measur...

FURTHER STUDY ON THE KINETIC ENERGY BALANCE1,,2

Abstract Various aspects of our studies of the kinetic energy balance are discussed, using an improved scheme of computing the horizontal and vertical transports of the kinetic energy with the observed wind and geopotential data over North America. On a firmer basis than before, it has been shown that there is a considerable amount of kinetic energy dissipated outside the planetary boundary layer, particularly at the jet-stream level. This also may imply that intensity of the atmospheric general circulation is significantly higher than is being assumed in most of the numerical models of the atmosphere.

Normal Mode Energetics of the General Circulation during the FGGE Year

Abstract Three-dimensional normal mode functions are applied to the analysis of the energetics of the general circulation during the FGGE year. The GFDL FGGE data are used for the computation of both the normal mode energetics and the standard spectral energetics. The normal mode energetics of the global circulation are presented in a barotropic and baroclinic decomposition for the zonal mean and eddy energies for the stationary and transient components of the flow. The energy generated in the zonal mean baroclinic component is first transformed to the eddy baroclinic component through the process of atmospheric baroclinic instability. It is then further transformed to eddy and zonal mean barotropic components by the nonlinear up-scale cascade of kinetic energy. The zonal mean kinetic energy thus maintains its barotropic structure by the activities of baroclinic waves. The time series of energy variables during the FGGE Northern Hemisphere winter clearly indicates a sequence of energy transformations from...

Problems of Large-Scale Kinetic Energy Balance—A Diagnostic Analysis in GARP

Currently available diagnostic studies on kinetic energy balance in the general circulation are reviewed as one of the basic scientific problems in GARP. The kinetic energy equation and several different approaches in the evaluation of energy variables are discussed in relation to real and modeled atmospheric data. Energy balance problems in the middle latitudes are examined in terms of linkages between processes from energy conversion to dissipation, balance within various systems of circulation, and interactions with sub-synoptic scale disturbances. The kinetic energy budget in large-scale disturbances and the general flow of the tropical circulation are contrasted with those in the middle latitudes. By clarifying the current essential problems in the energetics of the middle latitudes and tropics, ongoing diagnostic studies at the University of Missouri—Columbia and Purdue University are identified in the context of the GARP.

Energetics Characteristics of the Asian Winter Monsoon in the Source Region

Abstract Energetics characteristics of the Asian winter monsoon are studied with twice-daily upper air data during a 20-year period over its source region. It is found that the energetics features over Siberia, North-eastern Asia, China Main and the Japan Sea, are distinctly different reflecting the different roles and characteristic flow patterns of these regions in the system of the winter monsoon. Siberia, under the dominance of the anticyclonic flow, shows a general adiabatic destruction of kinetic energy through cross-isobaric motion. Northeastern Asia, under the influence of a major cyclonic system, is dominated by typical patterns of energy transformations as observed in most areas of transient synoptic disturbances. The strong westerlies dominate over the general area of the China Main, East China Sea and Japan Sea and the kinetic energy is intensely generated in this portion of the flow. Most of the kinetic energy generated over China Main is exported. Over the Japan Sea area where the series of ...

ON THE MERIDIONAL DISTRIBUTION OF SOURCE AND SINK TERMS OF THE KINETIC ENERGY BALANCE1,, 2

Abstract The latitude-height distributions of the kinetic energy generation and dissipation over North America are presented in a series of cross sections from 25° to 70° N, and from the surface to the 50-mb level. The generation was computed using the twice-daily observed wind and geopotential data for a 1-yr period. The dissipation was obtained for a 3-mo summer period as the residual term of the kinetic energy equation. Throughout all latitudes, the generation and dissipation have a maximum in the planetary boundary layer. They gradually reach a minimum in the mid-troposphere, then increase to another maximum at the jet stream level except in middle latitudes. In the upper troposphere, there seems to be a characteristic meridional distribution both for generation and dissipation. The generation is significantly large north and south of the middle latitude where the kinetic energy is adiabatically destroyed. Those latitudes of large generation in the upper troposphere are also characterized by high fric...

Spectral energetics of the observed and simulated Northern Hemisphere general circulation during blocking episodes

Abstract The spectral energetics of the Northern Hemisphere circulation during blocking episodes of the FGGE year is investigated with gridded analyses of observational data and Parallel simulation experiments. The purpose of this study is to describe the energetics distinctions of the observed and simulated blockings in the context of the general circulation and to assess the capability of the model to simulate blockings. In the observed circulation a pronounced winter blocking is developed and maintained by the nonlinear wave-wave interaction L(1) from the kinetic energy source for n = 3–10, where L(n) is the transfer of eddy kinetic energy from all other wavenumbers to wavenumber n. In the case of the. double blocking in the winter, both L(1) and L(2) support the blocking. The kinetic energy source of n=3–10 for upscale input at n = 1 and 2 is supported by the baroclinic conversion at n3–10. The simulated winter circulation shows strong baroclinic conversion at all wavenumbers, including ultralong wave...

A Study of Subsynoptic Scale Energy Transformations1,,2

Abstract Kinetic energy transformations from the view-point of energetics of the large-scale circulation are investigated with a series of subsynoptic scale radiosonde network soundings. Individual terms of the kinetic energy equation are evaluated along with the gradient form of the Richardson number. A bimodal character of the vertical profile of kinetic energy generation having maxima in the upper and lower troposphere that is similar to what we observe in the genera1 circulation-scale disturbances is observed in the subsynoptic scale disturbances studied. However, the inflow of kinetic energy into the area indicates that, on the average, more kinetic energy could be dissipated than generated even during intense thunderstorm activity. Large pulsations of kinetic energy generation and dissipation with time are observed. Extrema of upper level generation are observed to occur mainly in layers where the Richardson number is relatively low.