MCC and gull flight behavior

Wintertime observations of mesoscale cellular convection (MCC) over the East China Sea have resulted in criteria that have a remarkable similarity to those reported by Woodcock (1975) in the study of thermals and gull flight behavior. It has been determined that the surface wind speed (V) and the air-sea temperature difference (T) prescribe unique and compatible conditons for both the occurrence of MCC and soaring by sea gulls. Specifically, the onset of MCC when V is between 5 and 9 m s^–1 is inversely proportional to T in the range 5 to 7 °C. Elsewhere, the onset of MCC occurs under conditions of direct proportionality between V and T. Necessary conditions for the occurrence of MCC due to heating from below are T 5 °C and V 5 m s^–1. The boundaries of the convective regime for MCC are discussed and interpreted in accordance with the regime for sea-gull soaring and similarity concepts.     

Similarity scaling applied to sodar observations of the convective boundary layer above an irregular hill

Nine profiles of the temperature structure parameter C _T ² and the standard deviation of vertical velocity fluctuations ( _w) in the convective boundary layer (CBL) were obtained with a monostatic Doppler sodar during the second intensive field campaign of the First ISLSCP Field Experiment in 1987. The results were analyzed by using local similarity theory. Local similarity curves depend on four parameters: the height of the mixed layer (z _i ), the depth of the interfacial layer (), and the temperature fluxes at the top of the mixed layer (Q _i ) and the surface (Q _o). Values of these parameters were inferred from sodar data by using the similarity curve for C _T ² and observations at three points in its profile. The effects of entrainment processes on the profiles of C _T ² and _wnear the top of the CBL appeared to be described well by local similarity theory. Inferred estimates of surface temperature flux, however, were underestimated in comparison to fluxes measured by eddy correlation. The measured values of _wappeared to be slightly smaller than estimates based on available parmeterizations. These discrepancies might have been caused by experimental error or, more likely, by the distortion of turbulence structure above the site by flow over the nonuniform terrain at the observation site.     

Tropical Glacier and Ice Core Evidence of Climate Change on Annual to Millennial Time Scales

This paper examines the potential of the stable isotopic ratios, ¹⁸O/¹⁶O ( ¹⁸O_ice)and ²H/¹H ( D_ice), preserved in mid to low latitude glaciers as a toolfor paleoclimate reconstruction. Ice cores are particularly valuable as they contain additional data, such as dust concentrations, aerosol chemistry, and accumulation rates, that can be combined with the isotopic information to assist with inferences about the regional climate conditions prevailing at the time of deposition. We use a collection of multi-proxy ice core histories to explore the ¹⁸O-climate relationship over the last 25,000 years that includes both Late Glacial Stage (LGS) and Holocene climate conditions. These results suggest that on centennial to millennial time scales atmospheric temperature is the principal control on the ¹⁸O_ice of the snowfall that sustains these high mountainice fields.Decadally averaged ¹⁸O_ice records from threeAndean and three Tibetan ice cores are composited to produce a low latitude ¹⁸O_ice history for the last millennium. Comparison ofthis ice core composite with the Northern Hemisphere proxy record (1000–2000A.D.) reconstructed by Mann et al. (1999) and measured temperatures(1856–2000) reported by Jones et al. (1999) suggests the ice cores have captured the decadal scale variability in the global temperature trends. These ice cores show a 20th century isotopic enrichment that suggests a large scale warming is underway at low latitudes. The rate of this isotopically inferred warming is amplified at higher elevations over the Tibetan Plateau while amplification in the Andes is latitude dependent with enrichment (warming) increasing equatorward. In concert with this apparent warming, in situobservations reveal that tropical glaciers are currently disappearing. A brief overview of the loss of these tropical data archives over the last 30 years is presented along with evaluation of recent changes in mean ¹⁸O_ice composition. The isotopic composition of precipitation should be viewed not only as a powerful proxy indicator of climate change, but also as an additional parameter to aid our understanding of the linkages between changes in the hydrologic cycle and global climate.     

Examination of ‘global atmospheric temperature monitoring with satellite microwave measurements’: 2. Analysis of satellite data

Using Microwave Sounding Unit (MSU) channel 2 (Ch. 2, 53.74 GHz) data, Spencer and Christy (1992a) determined that the earth exhibits no temperature trend in the period 1979–90, while other authors find a temperature increase of roughly 0.1 K. Based on a theoretical analysis Prabhakara et al. (1995) showed that the information about the global atmospheric temperature deduced from MSU Ch. 2 observations has a small contamination, T ₂, as a result of the attenuation due to hydrometeors in the atmosphere. A method is developed in this study, that utilizes coincident measurements made by MSU in Ch. 1 (50.3 GHz), to estimate this T ₂ over the global oceans. The magnitude of T ₂ is found to be about 1 K over significant parts of the tropical oceanic rain belts and about 0.25 K over minor portions of the mid-latitude oceanic storm tracks. Due to events such as El Niôo, there is variability from year to year in the rain areas and rain intensity leading to significant change in the patterns of T ₂. The patterns of T ₂ derived for March 82 and March 83 reveal such a change. When averaged over the global oceans, from 50° N to 50° S, T ₂ has a value of 0.25 and 0.29 K for March 1982 and 1983, respectively. Due to these reasons the interannual temperature change derived by Spencer and Christy from MSU Ch. 2 will contain a residual hydrometeor effect. Thus in evaluating decadal trend of the global mean temperature of the order of 0.1 K from MSU Ch. 2 data one has to take into account completely the contamination due to hydrometeors.     

A Wind Tunnel Model for Quantifying Fluxes in the Urban Boundary Layer

Transport of pollution and heatout of streets into the boundary layer above is not currently understood and so fluxes cannot be quantified. Scalar concentration within the street is determined by the flux out of it and so quantifying fluxes for turbulent flow over a rough urban surface is essential. We have developed a naphthalene sublimation technique to measure transfer from a two-dimensional street canyon in a wind tunnel for the case of flow perpendicular to the street. The street was coated with naphthalene, which sublimes at room temperature, so that the vapour represented the scalar source. The transfer velocity w_T relates the flux out of the canyon to the concentration within it and is shown to be linearly related to windspeed above the street. The dimensionless transfer coefficient w_T/U represents the ventilation efficiency of the canyon (here, w_T is a transfer velocity,U is the wind speed at the boundary-layer top). Observed values are between 1.5 and 2.7 ×10^-3 and, for the case where H/W0 (ratio of buildingheight to street width), values are in the same range as estimates of transfer from a flat plate, giving confidence that the technique yields accurate values for street canyon scalar transfer. w_T/U varies with aspect ratio (H/W), reaching a maximum in the wake interference regime (0.3 < H/W < 0.65). However, when upstream roughness is increased, the maximum in w_T/U reduces, suggesting that street ventilation is less sensitive to H/W when the flow is in equilibrium with the urban surface. The results suggest that using naphthalene sublimation with wind-tunnel models of urban surfaces can provide a direct measure of area-averaged scalar fluxes.     

Effect of thermal stratification on the growth of the internal boundary layer

The growth of a two-dimensional internal boundary layer (IBL), which develops when a neutral or unstably stratified flow over a uniform terrain encounters a step-change in surface roughness, is numerically investigated by a higher-order turbulence closure theory. It is found that the thickness of the IBL increases as ~ x ⁿ, where x is the downstream distance from the roughness-transition line. For a given set of upstream conditions, the value of the exponent n depends only on the Monin-Obukhov length L, and it is approximately independent of the roughness-change parameter M = In (z01/z02). At large fetches, increases markedly with increasing instability.NRC-NAS Resident Research Associate at AFCRL, 1973–74     

Major wet interval in white mountains medieval warm period evidenced inδ 13C of bristlecone pine tree rings

A long ¹³C chronology was developed from bristlecone pine (Pinus longaeva) at the Methuselah Walk site in the White Mountains of California. The chronology represents cellulose from five-year ring groups pooled from multiple radii of multiple trees. The most dramatic isotopic event in the chronology appears from A.D. 1080–1129, when ¹³C values are depressed to levels ~ 2 below the mean for the period A.D. 925–1654. This isotopic excursion appears to represent a real event and is not an artifact of sampling circumstances; in fact, a similar excursion occurs in a previously-reported, independent ¹³C chronology from bristlecone pine. By carbon isotope fractionation models, the shift to low ¹³C values is consistent with abundant soil moisture, permitting leaf stomata to remain open, and allowing ready access of CO₂ from which carbon fixation may discriminate more effectively against¹³C in favor of¹²C. According to this model, the¹³C-depleted 50-yr isotopic excursion represents the wettest period in the White Mountains in the past 1000 yr, during which isotope-reconstructed July Palmer Drought Severity Indices averaged ~ +2.2.     

Temperature structure parameter measurements using differential temperature sensors

The comparison of C _infT ^sup2 estimates in the atmospheric boundary layer, from spectral and differential temperature (T) measurements, is discussed. Measurements of C _infT ^sup2 using these two methods are compared and the differences between the two are shown to be due to low-frequency enhancement of the T spectrum. Possible explanations for this effect are considered and attention is drawn to the significance of the resulting errors in boundary-layer turbulence measurements.Now at Department of Electrical and Electronic Engineering, Portsmouth Polytechnic, Anglesea Road, Portsmouth, U.K.Now at Department of Meteorology, University of Athens, Greece.     

A dynamical analysis of the drag conditions at the sea surface

When applied to a sea surface, shortcomings are noted for the ordinary classification of drag conditions at rigid underlying surfaces according to the Reynolds roughness number Re _s . It is shown that in the case of mobile underlying surfaces, it would be more natural to use the dynamical classification of drag conditions according to the order of magnitude of the ratio ( = /) of the momentum flux toward the waves ( _w) to the viscous momentum flux through the surface ( _w). The relevant estimates of for the main stages of development of the wind waves indicate that the observed values of the drag coefficient of the sea surface correspond to the case of underdeveloped roughness.     

High resolution climatic information from short firn cores,western Dronning Maud Land,antarctica

Ten meter firn cores were collected during the Swedish Antarctic Expedition to Dronning Maud Land, in 1988/89. The oxygen isotope stratigraphy in the cores was used to obtain a proxy-temperature record and a surface accumulation record for the last 15–30 years. The ¹⁸O record from cores on the ice shelf and the escarpment area, below 2000 m a.s.l., show high variability and little year-to-year correspondence to each other or with the temperature record from nearby Halley. A stacked firn core record was produced to avoid local variability and minor dating errors; this record shows more similarities to the Halley temperature record. The ¹⁸O records from high altitude cores show a much better correspondence to the Halley temperature record over the last 30 years, implying that the source of precipitation is more stable compared to the coastal area. The welldeveloped ¹⁸O stratigraphy in the cores from coastal Dronning Maud Land makes it promising for future work using ice cores as paleoclimatic records.     

A reversing temperature-difference measurement system for Bowen ratio determination

The design and performance of a reversing temperature difference measurement system are reported. This system employs five-junction copper-constantan thermopiles for the measurement of T and T _w, while a linearized thermistor is used to measure T _w. Field performance has been checked against a precision lysimeter as well as against a second temperature difference measurement system in which diodes are used for temperature measurement. In both cases, the agreement between the systems is satisfactory for the measurement of hourly values of the Bowen ratio.     

Height dependence of diurnal variations of wind velocity and water temperature near the air-sea interface of the tropical Atlantic

From measurements during the Atlantic Trade Wind Experiment (ATEX) 1969, amplitudes and phases of the diurnal harmonic water-temperature variation between the sea surface and 50-m depth and of the semi-diurnal wind variation between 1 and 8 m were obtained. If the vertical diffusion of heat in the ocean is thought to be constant, a coefficient of K= 320 cm² s^–1 in the equation of diffusion fits best the observed data in the mixed layer. However, the measurements point to a decrease of K with depth.The height variation of the semi-diurnal zonal wind wave is caused by the influence of eddy viscosity. Our data are well fitted by results of the equation of diffusion, using the assumption of Lettau (1974) that the transfer coefficient of vertical transport of momentum is not only a function of height but also depends on time because of the semi-diurnal variation of surface stress.     

Nearly steady convection and the boundary-layer budgets of water vapor and sensible heat

The budgets of water vapor and sensible heat in the convective atmospheric boundary (mixed) layer are analyzed by means of a simple slab approach adapted to steady large-scale advective conditions with radiation and cloud activity. The entrainment flux for sensible heat is assumed to be a linear function of the surface flux. The flux of water vapor at the top of the mixed layer is parameterized by extending the first-order Betts-Deardorff approach, i.e., by adopting linear changes for both the specific humidity and the flux across the mixed layer and across the inversion layer of finite thickness. In this way the dissimilarity of sensible heat and water vapor transport in the mixed layer can be taken into account. The experimental data were obtained from the Air Mass Transformation Experiment (AMTEX). The entrainment constant for sensible heat at the top of the mixed layer was found to have values similar to those observed in other weakly convective situations, i.e., around 0.4 to 0.6. This appears to indicate that the effect of mechanical turbulence was not negligible; however, the inclusion of this effect in the formulation did not improve the correlation. In contrast to the first-order approach, the zero-order approach, i. e., the jump equation commonly used for the flux of a scalar at the inversion, (ovwc ) _h = w_e c (where w _e is the entrainment velocity and c the concentration jump across the inversion), was found to be invalid and incapable of describing the data.     

Mixed-layer heat advection and entrainment during the sea breeze

A model is developed to simulate the potential temperature and the height of the mixed layer under advection conditions. It includes analytic expressions for the effects of mixed-layer conditions upwind of the interface between two different surfaces on the development of the mixed layer downwind from the interface. Model performance is evaluated against tethersonde data obtained on two summer days during sea breeze flow in Vancouver, Canada. It is found that the mixed-layer height and temperature over the ocean has a small but noticeable effect on the development of the mixed layer observed 10 km inland from the coast. For these two clear days, the subsidence velocity at the inversion base capping the mixed layer is estimated to be about 30 mm s^–1 from late morning to late afternoon. When the effects of subsidence are included in the model, the mixed-layer height is considerably underpredicted, while the prediction for the mean potential temperature in the mixed layer is considerably improved. Good predictions for both height and temperature can be obtained when values for the heat entrainment ratio,c, 0.44 and 0.68 for these two days respectively for the period from 1000 to 1300 LAT, were used. These values are estimated using an equation including the additional effects on heat entrainment due to the mechanical mixing caused by wind shear at the top of the mixed layer and surface friction. The contribution of wind shear to entrainment was equal to, or greater than, that from buoyant convection resulting from the surface heat flux. Strong wind shear occurred near the top of the mixed layer between the lower level inland flow and the return flow aloft in the sea breeze circulation.Symbols c entrainment parameter for sensible heat - c _p specific heat of air at constant pressure, 1010 J kg^–1 K^–1 - d ₁ the thickness of velocity shear at the mixed-layer top, m - Q _H surface sensible heat flux, W m^–2 - u _m mean mixed-layer wind speed, m s^–1 - u _* friction velocity at the surface, m s^–1 - w subsidence velocity, m s^–1 - W subsidence warming,^oC s^–1 - w _e entrainment velocity, m s^–1 - w _* convection velocity in the mixed layer, m s^–1 - x downwind horizontal distance from the water-land interface, m - y dummy variable forx, m - Z height above the surface, m - Z _i height of capping inversion, m - Z _m mixed-layer depth, i.e.,Z _i–Z_s, m - Z _s height of the surface layer, m - lapse rate of potential temperature aboveZ _i, K m^–1 - potential temperature step atZ _i, K - u _h velocity step change at the mixed-layer top - _m mean mixed-layer potential temperature, K     

The aqueous thermal boundary layer

This article reviews the available data, measurement techniques, and present understanding of the millimeter thick aqueous thermal boundary layer. A temperature difference between the surface and lower strata, T, of the order of a few tenths to –1 °C have been observed. Techniques ranging from miniature mercury thermometers and electrical point sensors to optical interferometry and infrared radiometry have been employed. Many processes influence the temperature structure in this thin boundary layer. Among them are: the net upward heat flux due to evaporation and sensible heat transfer; infrared and solar radiation; and the turbulence near the interface due to wind mixing, wave breaking and current shear. Presence of solute and surface-active materials stimulate or dampen these mixing processes thereby influencing boundary-layer thickness and temperature structure.Department of Atmospheric Sciences Contribution Number 354.     

The prediction of dust erosion by wind: An interactive model

We have devised a partial differential equation for the prediction of dust concentration in a thin layer near the ground. In this equation, erosion (detachment), transport, deposition and source are parameterised in terms of known quantities. The interaction between a wind prediction model in the boundary layer and this equation affects the evolution of the dust concentration at the top of the surface layer. Numerical integrations are carried out for various values of source strength, ambient wind and particle size. Comparison with available data shows that the results appear very reasonable and that the model should be subjected to further development and testing.Notation (x, y, z, t) space co-ordinates and time (cm,t) - u, v components of horizontal wind speed (cm s^–1) - u _g, v_g components of the geostrophic wind (cm s^–1) - V=(u²+v²)^1/2 (cm s^–1) - (û v)= 1/(h – k) _k ^h(u, v)dz(cm s^–1) - V _* friction velocity (cm s^–1) - z ₀ roughness length (cm) - k ₁ von Karman constant =0.4 - V _d deposition velocity (cm s^–1) - V _g gravitational settling velocity (cm s^–1) - h height of inversion (cm) - k height of surface layer (cm) - potential temperature (°K) - _gr potential temperature at ground (°K) - _K potential temperature at top of surface layer (°K) - P pressure (mb) - P ₀ sfc pressure (mb) - C _p/C_v - (t)= /z lapse rate of potential temperature (°K cm^–1) - A(z) variation of wind with height in transition layer - B(z) variation of wind with height in transition layer - Cd drag coefficient - C _HO transfer coefficient for sensible heat - C dust concentration (g m^–3) - C _K dust concentration at top of surface layer (g m^–3) - D(z) variation with height of dust concentration - u, v, w turbulent fluctuations of the three velocity components (cm s^–1) - A ₁ constant coefficient of proportionality for heat flux =0.2 - Ri Richardson number - g gravitational acceleration =980 cm s^–2 - Re Reynolds number = - D _s thickness of laminar sub-layer (cm) - v molecular kinematic viscosity of air - coefficient of proportionality in source term - dummy variable - t time step (sec) - n time index in numerical equations On sabbatical leave at University of Aberdeen, Department of Engineering, September 1989–February 1990.     

A numerical modeling study of the marine boundary layer over the Gulf Stream during cold air advection

A two-dimensional mesoscale model has been developed to simulate the air flow over the Gulf Stream area where typically large gradients in surface temperature exist in the winter. Numerical simulations show that the magnitude and the maximum height of the mesoscale circulation that develops downwind of the Gulf Stream depends on both the initial geostrophic wind and the large-scale moisture. As expected, a highly convective Planetary Boundary Layer (PBL) develops over this area and it was found that the Gulf Stream plays an important role in generating the strong upward heat fluxes causing a farther seaward penetration as cold air advection takes place. Numerical results agree well with the observed surface fluxes of momentum and heat and the mesoscale variation of vertical velocities obtained using Doppler Radars for a typical cold air outbreak. Precipitation pattern predicted by the numerical model is also in agreement with the observations during the Genesis of Atlantic Lows Experiment (GALE).List of Symbols u east-west velocity [m s^–1] - v north-south velocity [m s^–1] - vertical velocity in coordinate [m s^–1] - w vertical velocity inz coordinate [m s^–1] - gq potential temperature [K] - q moisture [kg kg^–1] - scaled pressure [J kg^–1 K^–1] - U _g the east-south component of geostrophic wind [m s^–1] - V _g the north-south component of geostrophic wind [m s^–1] - vertical coordinate following terrain - x east-west spatial coordinate [m] - y north-south spatial coordinate [m] - z vertical spatial coordinate [m] - t time coordinate [s] - g gravity [m² s^–1] - E terrain height [m] - H total height considered in the model [m] - q _s saturated moisture [kg kg^–1] - p pressure [mb] - p ₀₀ reference pressure [mb] - P precipitation [kg m^–2] - vertical lapse rate for potential temperature [K km^–1] - L latent heat of condensation [J kg^–1] - C _p specific heat at constant pressure [J kg^–1 K^–1] - R gas constant for dry air [J kg^–1 K^–1] - R _v gas constant for water vapor [J kg^–1 K^–1] - f Coriolis parameter (2 sin ) [s^–1] - angular velocity of the earth [s^–1] - latitude [^o] - K _H horizontal eddy exchange coefficient [m² s^–1] - t integration time interval [s] - x grid interval distance inx coordinate [m] - y grid interval distance iny coordinate [m] - adjustable coefficient inK _H - subgrid momentum flux [m² s^–2] - subgrid potential temperature flux [m K s^–1] - subgrid moisture flux [m kg kg^–1 s^–1] - u _* friction velocity [m s^–1] - _* subgrid flux temperature [K] - q _* subgrid flux moisture [kg kg^–1] - w _* subgrid convective velocity [m s^–1] - z ₀ surface roughness [m] - L Monin stability length [m] - _s surface potential temperature [K] - k von Karman's constant (0.4) - v air kinematic viscosity coefficient [m² s^–1] - K _M subgrid vertical eddy exchange coefficient for momentum [m² s^–1] - K subgrid vertical eddy exchange coefficient for heat [m² s^–1] - K _q subgrid vertical eddy exchange coefficient for moisture [m² s^–1] - z _i the height of PBL [m] - h _s the height of surface layer [m]     

Temperature distribution and current system in a convectively mixed lake

During spring and autumn, many lakes in temperate latitudes experience intensive convective mixing in the vertical, which leads to almost isothermal conditions with depth. Thus the regime of turbulence appears to be similar with that characteristic of convective boundary layers in the atmosphere. In the present paper a simple analytical approach, based on boundary-layer theory, is applied to convective conditions in lakes. The aims of the paper are firstly to analyze in detail the temperature distribution during these periods, and secondly to investigate the current system, created by the horizontal temperature gradient and wind action. For these purposes, simple analytical solutions for the current velocities are derived under the assumption of depth-constant temperatures. The density-induced current velocities are shown to be small, in the order of a few mm/sec. The analytical model of wind-driven currents is compared with field data. The solution is in good qualitative agreement with observed current velocities under the condition that the wind field is steady for a relatively long time and that residual effects from former wind events are negligible.The effect of the current system on an approximately depth-constant temperature distribution is then checked by using the obtained current velocity fields in the heat transfer equation and deriving an analytical solution for the corrected temperature field. These temperature corrections are shown to be small, which indicates that it is reasonable to describe the temperature distribution with vertical isotherms.Notation T temperature - t time - x, y, z cartesian coordinates - molecular viscosity - _h , _v horizontal and vertical turbulent viscosity - K _h ,K _v horizontal and vertical turbulent conductivity - Q heat flux through the water surface - D depth - u, v, w average current velocity components inx, y andz directions - f Coriolis parameter - p pressure - density - g gravity acceleration - a constant in the freshwater state equation - h _s deviation from the average water surface elevation - L _*,H _* length and depth scale - U _*,W _* horizontal and vertical velocity scale - T temperature difference scale - bottom slope - u _* friction velocity at the water surface - von Karman constant - L Monin-Obukhov length scale - buoyancy parameter - l turbulence length scale - C ₁,C ₂,C ₃ dimensionless constants in the expressions for the vertical turbulent viscosity - , dimensionless vertical coordinate and dimensionless local depth - angle between surface stress direction andx-axis - T _bx ,T _by bottom stress components - c bottom drag coefficient     

Numerical simulation of turbulent convective flow over wavy terrain

By means of a large-eddy simulation, the convective boundary layer is investigated for flows over wavy terrain. The lower surface varies sinusoidally in the downstream direction while remaining constant in the other. Several cases are considered with amplitude up to 0.15H and wavelength ofH to 8H, whereH is the mean fluid-layer height. At the lower surface, the vertical heat flux is prescribed to be constant and the momentum flux is determined locally from the Monin-Obukhov relationship with a roughness lengthz _o=10^–4 H. The mean wind is varied between zero and 5w _*, wherew _* is the convective velocity scale. After rather long times, the flow structure shows horizontal scales up to 4H, with a pattern similar to that over flat surfaces at corresponding shear friction. Weak mean wind destroys regular spatial structures induced by the surface undulation at zero mean wind. The surface heating suppresses mean-flow recirculation-regions even for steep surface waves. Short surface waves cause strong drag due to hydrostatic and dynamic pressure forces in addition to frictional drag. The pressure drag increases slowly with the mean velocity, and strongly with /H. The turbulence variances increase mainly in the lower half of the mixed layer forU/w _*>2.     

An aircraft study of turbulence dissipation rate and temperature structure function in the unstable marine atmospheric boundary layer

The dissipation rate of turbulent kinetic energy, , and the temperature structure function parameter, C _T ², have been measured over water from the near surface (Z = 3 m) to the top of the boundary layer. The near surface values of and C _T ² were used to calculate the velocity and temperature Monin-Obukhov scaling parameters u _* and T _*. The data collected during unstable lapse rates were used to evaluate the feasibility of extrapolating the values of and C _T ² as a function of height with empirical scaling formulae. The dissipation rate scaling formula of Wyngaard et al. (l971 a) gave a good fit to an average of the data for Z < 0.8 Z _i. In the surface layer the scaling formula of Wyngaard et al. (1971b) disagreed with the C _T ² values by as much as 50%. This disagreement is due to an unexpected reduction in the measured values of C _T ² forZ < 30 m. At this point it is not clear if the discrepancy is a unique property of the marine boundary layer or if it is simply some unknown instrumental or analytical problem. The mixed layer scaling results were similar to the overland results of Kaimal et al. (1976).