On the Radiation Budget of the Troposphere over the Northern Hemisphere (II)

Real global data of seven levels (surface pressure, geopotential heights for 700, 500, 300, 200, 100, and 70 mb) analyzed by Baumhefner for the period of 15-19 J anuary 1958 (IGY) are used to evaluate the transports of angular momentum, water vapor, and energy due to mean meridional circulation and eddy motions. Since only mass fields are analyzed, a technique is used to claim the fields of wind and water vapor. With the aid of a six-layer general circulation model developed at the National 'Center for Atmospheric Research (NCAR), short-range forecasts are made from analyzed initial mass fields with geostrophic wind as an initial condition. A climatological zonal mean specific humidity distribution for January is assumed as the initial field for water vapor. It is found that the wind and water vapor fields evolving after 24 hours of time integration appear to be usable for the evaluation of various transport quantities.The computed mean and eddy transports of momentum, water vapor, and energy are compared with those of various observational sources and of a simulated January starting from an isothermal atmosphere with the NCAR general circulation model. It is shown that the values of various transport quantities for the January 1958 case in the Northern Hemisphere are in reasonable agreement with those of other sources. However, the values of transport quantities in the Southern Hemisphere are underestimated due to weak wave activity. The weakness of eddy motions in the Southern Hemisphere is presumably attributed to difficulty in the initial data analysis owing to sparsity of observation stations in the Southern Hemisphere.In this study, we intend to demonstrate that the diagnostic analyses of the mean and eddy transports of various meteorological quantities can be performed from basic data sets with the use of a general circulation model as the means of imposing dynamical constraints among meteorological variables. 573

Section: Distribution Of Heating Ratessupporting

confidence: 90%

Mean and Eddy Transports of Angular Momentum, Water Vapor, and Energy in the Global Atmosphere

Kasahara

1971

“…The value of *'*' for 1962 estimated by Nitta (1970 b) was a third of the value of -a'*' in this study for 1956 and we consider that Table 2.. Heating rate by net radiative process averaged in the western Pacific region between 0*N and 10*N. (After Katayama, 1967). Unit is ° C/day.…”

Section: Energy Budget Of Wave Disturbancesmentioning

confidence: 47%

Energy Budget of Wave Disturbances over the Marshall Islands During the Years of 1956 and 1958

Nitta

1972

Based on the data in the Marshall Islands obtained in 1956 and 1958, vertical velocities and heat source associated with tropical wave disturbances are estimated and the energy transformation of the disturbances are examined. An approximate estimate of the upward transport of sensible and latent heat by small-scale convective motions is also obtained. Eddy available potential energy is generated by the heat of condensation and is transformed to the eddy kinetic energy in the upper troposphere centered about 300 mb. Energy flux is upward above the level about 300 mb and downward below that level. Other terms of energy transformations such as the conversions from mean kinetic energy and from mean potential energy are one or two order of magnitude smaller than terms of generation and conversion of eddy available potential energy. The sensible and the latent heat supplied from the sea surface is transported upward by the cumulus convecsions and strong convective transport corresponds to the upward motion of the large-scale disturbances. A non-dimensional heating parameter *(p) is also obtained and is compared with that used in theoretical studies.

“…In the evaluations mentioned above, it is assumed that eddy (convective) transport of heat and moisture vanishes at Ptop. The value of cooling rate due to net radiation dTR/dt is obtained from the climatological distribution on the vertical cross section along 30N latitude circle for January presented by Katayama (1967). The adopted values for the SFC-850mb, 850-700mb and 700-500mb layers are 0.042, 0.035 and 0.042 C/hour respectively.…”

Section: Datamentioning

confidence: 99%

Large-Scale Aspects of Air-Mass Transformation over the East China Sea during AMTEX'74

Ninomiya¹

1975

Large-scale aspects of the air-mass transformation over the East China Sea during AMTEX '74 (February 14-28, 1974) are studied based on the synoptic and heat energy budget analysis.Both the synoptic and budget situations over the East China Sea vary according to the alternation of the subtropical air-mass and the polar air-mass.The synoptic situations in the earlier period are characterized by the small air-sea temperature difference, the southerly wind and very weak thermal advection in the lower layer. The amount of the total heat energy supply from the sea is small (200ly/day) during this period. The moisture and heat supply from the sea primarily contributes to the local time change of moisture and temperature in the lower layer.The synoptic situations for the latter period are characterized by the large air-sea temperature difference, the northerly wind, and strong cold advection in the lower troposphere below the inversion layer. The amount of the total heat energy supply from the sea is as large as 1200 ly /day. In spite of the strong cold advection, the temperature fall (*T/*t) is small, because the cold advection is primarily balanced by the diabatic heating due to the energy supply from the sea. The results of the budget calculations also indicate that the diabatic heating is mainly confined in the lower layer below the inversion.The time variation of the vertical stability in the lower troposphere is also analysed in relation to the formation of the inversion layer. The results of analysis indicate that the differential thermal advection is the primal factor to control the vertical stability. It is also shown that the differential diabatic heating cancels some part of the differential advection during the period of cold air outbreak.