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Aircraft observations of the Ekman layer during the Joint Air-sea Interaction Experiement
OLR(1986)33 (3)
B. MarineMeteorology
Linear relationships were sought using the empirical orthogonal function technique on the data fields stratified into summer and winter data sets. The first winter eigenvector/amplitude coefficient pair resembled an El Nh3o/Southern Oscillation event. No other statistically significant eigenvector/amplitude coefficient pairs were obtained. Generally the relationships between the three pairs of variables were statistically insignificant. Meteorol. Satellite Center, Japan Meteorol. Agency, Kiyose, Japan. 86:1486 Nicholls, S., 1985. Aircraft observations of the Ekman layer during the Joint Air-Sea Interaction Experiment. Q. Jl R. met. Soc., 111(468):391-426. Observations from eight occasions during JASIN when the atmospheric boundary layer was neutrally stable are used to estimate the momentum and turbulent kinetic energy balances throughout the depth of the Ekman layer. The terms consistently balanced and their importance was described by Ekman scaling. The turbulent momentum transport was confined to high wavenumbers whose characteristics were a function of depth and stability. Implications for the heat and water mass balances arc discussed. Meteorological Office, Bracknell, UK. (wbo) ~:14~ Overland, J.E., 1985. Atmospheric boundary layer structure and drag coefficients over sea ice. J. geophys. Res, 90(C5):9029-9049. Air/sea drag coefficients for first-year ice are estimated from recent aircraft measurements. Results reconcile the range of observed drag coefficients for all sea ice types, based on ice roughness and seasonal meteorology, i.e., structure of the atmospheric boundary layer. Values are given for regional stress associated with regional winds since sea ice is heterogeneous on scales less than 20 km. The relation between geostrophic and surface winds is reviewed; drag coefficients are proposed for a wide range of ice concentrations and atmospheric conditions based upon inversion height. Pacific Mar. Lab., NOAA, Seattle, WA, USA. (wbo) 86:1488 Wu, Jin, 1985. Parameterlzatlon of wind.str~-~s cooffldents over water surfaces. J. geophys. Res, 90(C5):9069-9072. At all fetches under various wind velocities the wind-stress coefficient is related to the nondimensional fetch. A unique relationship was found between the wave age and nondimensional fetch; the former can therefore be used as an alternate
215
parameter for the latter, especially useful for the open sea. Air-Sea Interaction Lab., College of Mar. Studies, Univ. of Delaware, Lewes, DE, USA.
B170. C~ulation 86:1489 Sardeshmukh, P.D. and B.J. Hoskins, 1985. Vorticity balances in the tro~es daring the 1982--83 El Nifio-Southern Oscillation event. Q. Jl R. met. Soc., 111(468):261-278. Mean vorticity balances in the tropical atmosphere were determined from archived data at one upper (150 nab) and one lower (850 rob) tropospheric level. The lower level balance is a linear Sverdrup balance between stretching and advection of planetary vorticity; the upper, nonlinear with a primary balance between stretching and advection of absolute vorticity by the time-mean horizontal flow. Transients play a smaller but significant role; vertical advection and twisting of vorticity can be neglected. Nonlinear character is highlighted by the failure of a linearized barotropic model to simulate anomalous flow in the central Pacific. Stretching in regions of strong convective outflow leads to rapid spin-down of the local absolute vorticity and the production of a region of almost zero absolute circulation. Dept. of Meteorology, Univ. of Reading,
UK. (wbo)
B250.
Clouds
86:1490 Chen, Yi-Leng, 1985. Diagnosis of the net cloud mass flux In GATE. J. atmos. Sci, 42(16): 1757-1769. A diagnostic analysis of the net cloud mass flux for the mean state of Phase III is presented. It is hypothesized that a considerable portion of the moisture detrained from tall clouds is transported horizontally toward higher latitudes by horizontal eddy fluxes. The diagnosed environmental subsidence has a maximum in the midtroposphere and is less than 1.5 times the sinking motion required by the radiative cooling in low levels. The vertical profile of the diagnosed net detrainment rate suggests three primary detrainment layers: below 800 mb, between 700 and 500 mb, and above 300 mb. Dept. of Meteorol., Univ. of Hawaii, Honolulu, HI 96822, USA. 86:1491
Curry, J.A. and G.F. Herman, 1985. betwo~ ~ heat and ~
B. MarineMeteorology
Linear relationships were sought using the empirical orthogonal function technique on the data fields stratified into summer and winter data sets. The first winter eigenvector/amplitude coefficient pair resembled an El Nh3o/Southern Oscillation event. No other statistically significant eigenvector/amplitude coefficient pairs were obtained. Generally the relationships between the three pairs of variables were statistically insignificant. Meteorol. Satellite Center, Japan Meteorol. Agency, Kiyose, Japan. 86:1486 Nicholls, S., 1985. Aircraft observations of the Ekman layer during the Joint Air-Sea Interaction Experiment. Q. Jl R. met. Soc., 111(468):391-426. Observations from eight occasions during JASIN when the atmospheric boundary layer was neutrally stable are used to estimate the momentum and turbulent kinetic energy balances throughout the depth of the Ekman layer. The terms consistently balanced and their importance was described by Ekman scaling. The turbulent momentum transport was confined to high wavenumbers whose characteristics were a function of depth and stability. Implications for the heat and water mass balances arc discussed. Meteorological Office, Bracknell, UK. (wbo) ~:14~ Overland, J.E., 1985. Atmospheric boundary layer structure and drag coefficients over sea ice. J. geophys. Res, 90(C5):9029-9049. Air/sea drag coefficients for first-year ice are estimated from recent aircraft measurements. Results reconcile the range of observed drag coefficients for all sea ice types, based on ice roughness and seasonal meteorology, i.e., structure of the atmospheric boundary layer. Values are given for regional stress associated with regional winds since sea ice is heterogeneous on scales less than 20 km. The relation between geostrophic and surface winds is reviewed; drag coefficients are proposed for a wide range of ice concentrations and atmospheric conditions based upon inversion height. Pacific Mar. Lab., NOAA, Seattle, WA, USA. (wbo) 86:1488 Wu, Jin, 1985. Parameterlzatlon of wind.str~-~s cooffldents over water surfaces. J. geophys. Res, 90(C5):9069-9072. At all fetches under various wind velocities the wind-stress coefficient is related to the nondimensional fetch. A unique relationship was found between the wave age and nondimensional fetch; the former can therefore be used as an alternate
215
parameter for the latter, especially useful for the open sea. Air-Sea Interaction Lab., College of Mar. Studies, Univ. of Delaware, Lewes, DE, USA.
B170. C~ulation 86:1489 Sardeshmukh, P.D. and B.J. Hoskins, 1985. Vorticity balances in the tro~es daring the 1982--83 El Nifio-Southern Oscillation event. Q. Jl R. met. Soc., 111(468):261-278. Mean vorticity balances in the tropical atmosphere were determined from archived data at one upper (150 nab) and one lower (850 rob) tropospheric level. The lower level balance is a linear Sverdrup balance between stretching and advection of planetary vorticity; the upper, nonlinear with a primary balance between stretching and advection of absolute vorticity by the time-mean horizontal flow. Transients play a smaller but significant role; vertical advection and twisting of vorticity can be neglected. Nonlinear character is highlighted by the failure of a linearized barotropic model to simulate anomalous flow in the central Pacific. Stretching in regions of strong convective outflow leads to rapid spin-down of the local absolute vorticity and the production of a region of almost zero absolute circulation. Dept. of Meteorology, Univ. of Reading,
UK. (wbo)
B250.
Clouds
86:1490 Chen, Yi-Leng, 1985. Diagnosis of the net cloud mass flux In GATE. J. atmos. Sci, 42(16): 1757-1769. A diagnostic analysis of the net cloud mass flux for the mean state of Phase III is presented. It is hypothesized that a considerable portion of the moisture detrained from tall clouds is transported horizontally toward higher latitudes by horizontal eddy fluxes. The diagnosed environmental subsidence has a maximum in the midtroposphere and is less than 1.5 times the sinking motion required by the radiative cooling in low levels. The vertical profile of the diagnosed net detrainment rate suggests three primary detrainment layers: below 800 mb, between 700 and 500 mb, and above 300 mb. Dept. of Meteorol., Univ. of Hawaii, Honolulu, HI 96822, USA. 86:1491
Curry, J.A. and G.F. Herman, 1985. betwo~ ~ heat and ~