Some measurements of the flux of infra-red radiation in the atmosphere

1956 ◽  
Vol 236 (1205) ◽  
pp. 175-186 ◽  
Keyword(s):  
Kinetic Energy ◽  
Lower Stratosphere ◽  
Atmospheric Radiation ◽  
Radiative Cooling ◽  
Classical View ◽  
Upper Troposphere ◽  
Infra Red ◽  
The Moment ◽  
Effective Radiation ◽  
Red Radiation

For the continual development of the kinetic energy of the winds, it is necessary for the upper troposphere to be cooled by radiation. Results are reported of nine aircraft ascents on which the upward and downward flows of infra-red radiation were measured and com­pared with values calculated using the radiation charts of Elsasser and Yamamoto. The divergence of radiative flux deduced from these measurements clearly shows that the cooling in the troposphere is not very different from that calculated from radiation charts. The importance of clouds on the radiative pattern is demonstrated; at the moment, incom­plete knowledge of cloud structure will be the chief factor limiting the value of calculations of atmospheric radiation. The measurements are of very limited value in the stratosphere, since, for the very small quantities of water there, the effective radiation is in the rotation band of water vapour ( λ between 30 and 70 μ ) and the radiometer used was not sensitive to these wavelengths. If the use of radiation charts is extrapolated to these conditions they indicate that the radiative cooling continues in the lower stratosphere. This is in contrast with the ‘classical’ view that the stratosphere is in radiative equilibrium.

scholarly journals Mesoscale Horizontal Kinetic Energy Spectra of a Tropical Cyclone

2018 ◽  
Vol 75 (10) ◽  
pp. 3579-3596 ◽  
Author(s):  
Yuan Wang ◽  
Lifeng Zhang ◽  
Jun Peng ◽  
Saisai Liu
Keyword(s):  
Tropical Cyclone ◽  
Kinetic Energy ◽  
Gravity Waves ◽  
Lower Stratosphere ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Physical Processes ◽  
Upper Troposphere ◽  
Mature Period ◽  
Vertically Propagating

A high-resolution cloud-permitting simulation with the Weather Research and Forecasting (WRF) Model is performed to investigate the mesoscale horizontal kinetic energy (HKE) spectra of a tropical cyclone (TC). The spectrum displays an arc-like shape in the troposphere and a quasi-linear shape in the lower stratosphere for wavelengths below 500 km during the mature period of the TC, while they both develop a quasi −5/3 slope. The total HKE spectrum is dominated by its rotational component in the troposphere but by its divergent component in the lower stratosphere. Further spectral HKE budget diagnosis reveals a generally downscale cascade of HKE, although a local upscale cascade gradually forms in the lower stratosphere. However, the mesoscale energy spectrum is not only governed by the energy cascade, but is evidently influenced also by other physical processes, among which the buoyancy effect converts available potential energy (APE) to HKE in the mid- and upper troposphere and converts HKE to APE in the lower stratosphere, the vertically propagating inertia–gravity waves transport the HKE from the upper troposphere to lower and higher layers, and the vertical transportation of convection always transports HKE upward.

scholarly journals Mesoscale Energy Spectra of the Mei-Yu Front System. Part I: Kinetic Energy Spectra

2013 ◽  
Vol 71 (1) ◽  
pp. 37-55 ◽  
Author(s):  
Jun Peng ◽  
Lifeng Zhang ◽  
Yu Luo ◽  
Yun Zhang
Keyword(s):  
Kinetic Energy ◽  
Lower Stratosphere ◽  
Buoyancy Flux ◽  
Energy Spectra ◽  
Mature Stage ◽  
Flux Divergence ◽  
Negative Contribution ◽  
Vertical Pressure ◽  
Upper Troposphere ◽  
Mature Phase

Abstract The mesoscale kinetic energy (KE) spectra of the mei-yu front system are investigated through idealized numerical simulations. In the mature stage, the upper-tropospheric KE spectrum resembles a −3 power law for wavelengths between 1000 and 400 km and shallows to a slope of approximately − at smaller wavelengths. A similar behavior can be observed in the lower stratosphere. At both levels, the rotational KE spectrum shallows nearly to the same extent as the divergent KE spectrum at smaller wavelengths, accounting for the transition in the total KE spectrum. About 12 h after the latent heating is turned off, the mesoscale KE spectra hardly show the distinct spectral transition, especially in the upper troposphere. The spectral KE budget for various height ranges is analyzed and compared. In the upper troposphere, the mesoscale KE is deposited through the buoyancy flux and removed by the advective nonlinearity and vertical pressure flux divergence. The buoyancy flux spectrum in the mature phase has a peak at scales of around 300 km and a plateau throughout the mesoscale, which suggests a significant injection of KE in the mesoscale. The negative contribution of the advective nonlinearity demonstrates that to some extent the mesoscale KE derives from a nonlinear upscale cascade, with the buoyancy-produced energy source located at the lower end of mesoscale spectrum. In the lower stratosphere, the mesoscale KE is deposited through the advective nonlinearity and vertical pressure flux divergence and removed by the buoyancy flux. This suggests that the lower-stratospheric KE spectrum is influenced by both the downscale energy cascade and vertically propagating IGWs.

scholarly journals Mesoscale Energy Spectra of the Mei-Yu Front System. Part II: Moist Available Potential Energy Spectra

2014 ◽  
Vol 71 (4) ◽  
pp. 1410-1424 ◽  
Author(s):  
Jun Peng ◽  
Lifeng Zhang ◽  
Yu Luo ◽  
Chunhui Xiong
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Lower Stratosphere ◽  
Vertical Flux ◽  
Energy Spectra ◽  
Spectral Energy ◽  
Positive Contribution ◽  
Spectral Slope ◽  
Upper Troposphere ◽  
Available Potential Energy

Abstract In Part II of this study, a new formulation of the spectral energy budget of moist available potential energy (MAPE) and kinetic energy is derived. Compared to previous formulations, there are three main improvements: (i) the Lorenz available potential energy is extended into a general moist atmosphere, (ii) the water vapor and hydrometeors are taken into account, and (iii) it is formulated in a nonhydrostatic framework. Using this formulation, the mesoscale MAPE spectra of the idealized mei-yu front system simulated in Part I are further analyzed. At the mature stage, the MAPE spectra in the upper troposphere and lower stratosphere also show a distinct spectral transition in the mesoscale: they develop an approximately −3 spectral slope for wavelengths longer than 400 km and − spectral slope for shorter wavelengths. In the upper troposphere, mesoscale MAPE is mainly deposited through latent heating and subsequently converted to other forms of energy at the same wavenumber. At wavelengths longer than roughly 400 km, the conversion of MAPE to horizontal kinetic energy (HKE) dominates, while at shorter wavelengths, the mechanical work produced by convective systems primarily adds to the potential energy of moist species and only secondarily generates HKE. However, this secondary conversion is enough to maintain the mesoscale − HKE spectral slope. Another positive contribution comes from the divergence term and the vertical flux. In the lower stratosphere, the main source of mesoscale MAPE is the conversion of HKE, although the vertical flux and the spectral transfer also have notable contributions.

scholarly journals The Climate Impact of Past Changes in Halocarbons and CO2 in the Tropical UTLS Region

2014 ◽  
Vol 27 (23) ◽  
pp. 8646-8660 ◽  
Author(s):  
Charles McLandress ◽  
Theodore G. Shepherd ◽  
M. Catherine Reader ◽  
David A. Plummer ◽  
Keith P. Shine
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Climate Impact ◽  
Ocean Model ◽  
Radiative Cooling ◽  
Point Temperature ◽  
Upper Troposphere ◽  
Adiabatic Cooling ◽  
Cold Point

Abstract A chemistry–climate model coupled to an ocean model is used to compare the climate impact of past (1960–2010) changes in concentrations of halocarbons with those of CO2 in the tropical upper troposphere and lower stratosphere (UTLS). The halocarbon contribution to both upper troposphere warming and the associated increase in lower stratospheric upwelling is about 40% as large as that due to CO2. Trends in cold-point temperature and lower stratosphere water vapor are positive for both halocarbons and CO2, and are of about the same magnitude. Trends in lower stratosphere ozone are negative, due to the increased upwelling. These increases in water vapor and decreases in lower stratosphere ozone feed back onto lower stratosphere temperature through radiative cooling. The radiative cooling from ozone is about a factor of 2 larger than that from water vapor in the vicinity of the cold-point tropopause, while water vapor dominates at heights above 50 hPa. For halocarbons this indirect radiative cooling more than offsets the direct radiative warming, and together with the adiabatic cooling accounts for the lack of a halocarbon-induced warming of the lower stratosphere. For CO2 the indirect cooling from increased water vapor and decreased ozone is of comparable magnitude to the direct warming from CO2 in the vicinity of the cold-point tropopause, and (together with the increased upwelling) lowers the height at which CO2 increases induce stratospheric cooling, thus explaining the relatively weak increase in cold-point temperature due to the CO2 increases.

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