912 A. Physical Oceanography OLR (1987) 34 ( 11 )

presented which includes data identification, anal- ysis of principles of data distribution, adjustment of obtained averages to mid-month, interpolation of adjusted averages, and smoothing of the norms.

87:61104 Carter, E.F. and A.R. Robinson, 1987. Analysis

models for the estimation of oceanic fields. J. atmos, ocean. Technol., 4(1):49-74.

A general model for statistically optimal estimates is presented for dealing with scalar, vector and mul- tivariate data sets. The method deals with aniso- tropic fields treating space and time dependence equivalently. Problems addressed include analysis, or production of synoptic time series of regularly gridded fields from irregular and gappy datasets, and the estimate of fields by compositing observations from several different instruments and sampling schemes. Technical issues are discussed, including convergence of statistical estimates, choice of rep- resentation of correlations, influential domain of an observation, and efficiency of numerical compu- tations. Center for Earth and Planetary Phys., Harvard Univ., Cambridge, MA 02138, USA.

87:60115 Donelan, M.A. and W.J. Pierson Jr., 1987. Radar

scattering and equilibrium ranges in wind-gen- erated waves with application to scatterometry. J. geophys. Res., 92(C5):4971-5029.

A composite, divided scale model for radar back- scatter from the ocean surface is constructed on the assumptions that the primary scattering mechanism is Bragg scattering and that the shortwave energy density reflects a balance between direct wind forcing and dissipation. The effects of tilt and modulation of the Bragg resonant waves by longer waves are included along with the contribution from specular reflection at low incidence angles. The model is tested against aircraft circle flight K,, band radar backscatter measurements, and then is exer- cised over a much wider wind speed range from L band to Ku band. The results indicate a complicated dependence of radar backscatter on wind speed, water temperature, and fetch and duration-depend- ent wave properties, in strong contrast with current power law models, and explain some of the incon- sistencies in the analysis of scatterometer data. Nat. Water Res. Inst., Canada Centre for Inland Waters, Burlington, ON, L7R 4A6, Canada.

87:6006 Eisler, T.J., 1987. Critique of a method of Munk and

Wuuseh for evaluating performance of acoustic tomography. J. geophys. Res., 92(C5):5052-5060.

In ocean acoustic tomography, acoustic travel times along multipaths between sources and receivers are inverted to estimate sound speed and currents in the region sampled by ray paths. The important meas- ures of system performance are resolution, variance, and sidelob contamination. A methodology for investigating trade-off relations among these quan- tities based on a layered model of the medium is examined and faulted because it is an intrinsic defect of the discrete approach that in forcing the reso- lution matrix close to the identity, it allows cancel- lation of positive and negative acceptance within layers. For models with turning depths within layers, the resolution matrix may be virtually perfect, while true resolution properties are nevertheless patho- logically degraded and estimates fail to approximate true layer averages. The use in inversions of weightings derived from a priori knowledge is also criticized. Natl. Ocean Serv., NOAA, Rockville, MD 20852, USA.

87:6007 Evans, J.C., D.B. Haidvogel and W.R. Holland,

1987. A review of numerical ocean modeling (1983-1986): midlatitude mesoscale and gyre- scale. Revs Geophys., 25(2):235-244.

Numerical results show great similarity to recent thermocline theories, but also some important differences--ventilation of the 'pool zone' by con- vective processes is substantial and solutions em- ploying explicitly-resolved eddies differ significantly from their equilibrium counterparts. Inverse meth- ods provide improved estimates of meridional heat transport and tropical upwelling of tracers. The influence of the western boundary on circulation of the gyre interior is beginning to be understood. Research has focused on jets, the generation of deep mean flows by eddy activity, constraints on the structure of isolated vortices, and transport of salinity by Gulf Stream rings. In anticipation of a dramatic increase in the oceanic observational data base, new modeling techniques for data assimilation and prediction are being developed. NCAR, Boul- der, CO, USA.

87:6008 Guissard, A.C., 1987. Response to 'Review of the full

wave solutions for rough surface scattering and depolarization: comparisons with geometric and physical optics, perturbation, and two-scale hybrid solutions' by E. Bahar. J. geophys. Res., 92(C5): 5225-5227.

The two-scale model can be applied for certain classes of random rough surfaces (as the ocean surface for moderate wind speeds) and the full wave method is not as rigorous and general as is claimed