OLR (1985) 32 (12) B. Marine Meteorology 1001

monitoring monsoon circulation and year-to-year variability. Here, monthly mean OLR data are analyzed for dominant eigenvector patterns, with the first three explaining nearly 93% of the total variance, being associated respectively with a sea- sonal shift in the cloudiest area of the ITCZ, a phase lag relationship between north India and the tropics, and the major features of the northeast monsoon over southeastern India. Interannual OLR variation shows close relationships to total monsoon rainfall over India. Indian Inst. of Tropical Meteorol., Pune 411005, India. (fcs)

BI10. Climate, climatology

85:6964 Raynaud, D. and J.M. Barnola, 1985. An Antarctic

ice core reveals atmospheric CO 2 variations over the past few centuries. Nature, Lond., 315(6017): 309-31 I.

By analysing the air extracted from bubbles found in the ice, it is possible to determine the air compo- sition, and thus its CO 2 content, for the period during which the air was trapped. Results obtained from an Antarctic ice core indicate that the back:- ground level could have been as low as 260 ppmv before the major anthropogenic influence and suggest that the so-called 'pre-industrial' CO 2 level was not constant over the few hundred years preceding the nineteenth century. Lab. de Glac. et Geophys. de l'Environ., BP 96, 38402 St. Martin d'Heres Cedex, France.

85:6965 Wigley, T.M.L. and M.E. Schlesinger, 1985. Ana-

lytical solution for the effect of increasing CO2 on global mean temperature. Nature, Lond., 315(6021):649-652. Climatic Res. Unit, Univ. of East Anglia, Norwich NR4 7T J, UK.

BI40. Air-sea interactions

85:6966 Adamec, David and R.L. Elsberry, 1985. Response

of an intense oceanic current system to cross- stream cooling events. J. phys. Oceanogr., 15(3): 273-287.

Shifts in location and strength of an intense oceanic flow such as the Gulf Stream in response to cross-stream gradient cooling are studied using 2-D simulations. The response is highly dependent on the vertical exchanges of both heat and momentum.

Several case studies in which these exchanges are varied are discussed. Further simulations in which surface wind stress varies are also presented and compared with cases of only thermal forcing. Dept. of Meteorol., Naval Postgrad. Sch., Monterey, CA 93943, USA. (who)

85:6967 Anderson, D.L.T. and J.P. McCreary, 1985. Slowly

propagating disturbances in a coupled ocean- atmosphere model. J. atmos. Sci., 42(6).'615-629.

A previously developed simple, coupled ocean- atmosphere model of E1 Nifio and the Southern Oscillation is extended to include a reduced gravity ocean model wih explicit thermodynamics with both horizontal advection and vertical redistribution of heat. The atmosphere is modeled as a linear, single baroclinic mode driven by surface latent heat convection which is specified in terms of the ocean temperature. Land, with prescribed surface convec- tion, is also included. Three cases of land-ocean configuration, no land and a bounded ocean with strong convection either east or west of the ocean, are studied and compared with observations. Dept. of Atmos. Phys., Clarendon Lab., Oxford OX1 3PU, UK. (wbo)

85:6968 Birman, B.A. and E.V. Balashova, 1985. On the

problem of calculating the fields of tangential stress of wind near the ocean surface. Meteor- ologiya Gidrol., 3:75-82. (In Russian, English abstract.)

Results of calculating the modulus of the mean vector of tangential wind stress from the mean wind speed and its variability are close to those derived using standard time data when the tangential stress is calculated for each wind velocity measurement and then averaged. Fields of tangential wind stress near the surface of the North Atlantic are compared with data of Hellerman and Bunker. In tropical latitudes, the cross-correlation coefficients of fields are equal to 0.92 for March and 0.96 for August; differences in moderate latitudes are associated with wind velocity trends. Results demonstrate the dom- inant role of tropical latitudes in exchange of momentum between the ocean and atmosphere.

85:6969 Clarke, A.J. and K.H. Brink, 1985. The response of

stratified, frictional flow of shelf and slope waters to fluctuating large-scale, low-frequency wind forcing. J. phys. Oceanogr., 15(4):439-453.

Models are developed to examine large-scale, low- frequency, wind-driven fluctuations over the con- tinental shelf and slope in the presence of density

1002 B. Marine Meteorology OLR (1985)32 (12)

stratification and bottom friction. A general criterion for a barotropic shelf response to wind forcing at periods of a few days due to weather events is derived. Bottom-stress enhancement due to surface gravity waves is found to be important in this problem. Shelf and slope water responses are calculated for the CODE (Coastal Ocean Dynamics Experiment) area. Dept. of Oceanogr. and Geophys. Fluid Dynamics Inst., Florida State Univ., Talla- hassee, FL 32306, USA. (wbo)

85:6970 Cubasch, U., 1985. The mean response of the

ECMWF global model to the E! Nifio anomaly in extended range prediction experiments. A tmos. Ocean, 23(!):43-66.

Numerical experiments were carried out with the low-resolution version of the ECMWF's GCM to ascertain effects of the E1 Nifio SST anomaly. Intensification of the Hadley circulation and the subtropical jet, and a deepening of the Aleutian Low, clearly appear. Teleconnections in mid-lati- tudes could not be confirmed, however, leaving problematical the utility of such simple models to simulating mid-latitude responses. European Centre for Medium Range Weather Forecasts, Shinfield Park, Reading Berkshire RG2 9AX, UK. (fcs)

85:6971 Fennessy, M.J., L. Marx and J. Shukla, 1985.

General circulation model IGLASI sensitivity to 1982-83 equatorial Pacific sea surface temper- ature anomalies. Mon. Weath. Rev., 113(5):858- 864.

Equatorial Pacific precipitation increased signifi- cantly in a wide band stretching from just east of the dateline to the South American coast; west of this region, precipitation was reduced. The major con- tributor to tropical precipitation changes was the low-level moisture convergence. Largest evaporation differences were around 4 mm/d and occurred over the regions of highest SST. The tropical SLP field showed a marked Southern Oscillation pattern. A strong increase in the equatorial eastern Pacific 850 mb westerlies accompanied a large negative easterly wind anomaly at 200 mb. Tropical precipitation anomalies for 1982-83 were also closely related to the extent of very warm surface waters. Dept. of Meteorol., Univ. of Maryland, College Park, MD 20742, USA.

85:6972 Geisler, J.E., M.L. Blackmon, G.T. Bates and S.

Mufloz, 1985. Sen~itivity of January dlmate

response to the m sH~altude and position of equa- torial Pacific sea surface temperature anomalies. J. atmos. Sci., 42(10):1037-1049.

A change in the amplitude of an SST anomaly of fixed shape and position produces an equatorial Pacific precipitation anomaly just east of the dateline. The most significant midlatitude response is a feature resembling the teleconnection pattern known as the Pacific/North American (PNA) pat- tern. The midlatitude response is a geographically- fixed PNA pattern whose amplitude and statistical significance are smaller the farther east the SST anomaly; probability of exciting the PNA pattern decreases as the SST anomaly is moved eastward. Results support the conclusion that the PNA pattern is related to an unstable mode of the atmosphere deriving energy from the zonally asymmetric cli- matological mean flow. Dept. of Meteorol., Univ. of Utah, Salt Lake City, UT 84112, USA.

85:6973 Joffre, S.M., 1985. Effects of local accelerations and

baroclinity on the mean structure of the atmos- pheric boundary layer over the sea. Bounda~- layer Met., 32(3):237-255.

Observations over the frozen Baltic Sea are used to consider the influence of the thermal wind effect and inertial terms on mean wind profiles in the atmos- pheric boundary layer (ABL). Results suggest that the balanced wind at the top of the ABL, rather than the surface geostrophic wind, should be used to parameterize ABL processes. It is also found that local acceleration increases the cross-isobar angle when velocity increases along the mean wind direction, while the geostrophic drag coefficient is minimal for a cross-wind acceleration. Baroclinicity acts to increase the cross-isobar angle under cold air advection, yielding a maximum geostrophic drag when the thermal and surface geostrophic winds are parallel. Finnish Meteorol. Inst., Sahaajank, 22E. 00810 Helsinki, Finland. (fcs)

85:6974 Kershaw, R., 1985. Onset of the south-west monsoon

and sea--sorlace temperature anomalies in the Arabian Sea. Nature, Lond., 315(6020):561-563.

The onset period of the monsoon, 11-19 June 1979, was selected for international comparison of numer- ical prediction models. Two examples of numerical predictions highlight the role of SST, namely a control forecast using climatological SST's and an anomaly forecast using more realistic (and warmer) surface temperatures specified for the eastern Ara- bian Sea. Use of the more accurate SST's enables a better prediction of the development of a monsoon