The warm pool region of the western tropical Pacific is of particular interest to atmospheric dynamics because it represents a significant source of energy to the atmosphere. A better understanding of heat transfer driven by mesoscale and turbulent circulations within this region could lead to improved global circulation models, and therefore to improved prediction of global weather patterns. A first step to this understanding is to evaluate empirical data as well as the methods used to estimate heat transfer, or heat flux, at the surface. Of specific interest here are latent heat flux, the heat transfer associated with evaporation, and sensible heat flux, the heat transfer associated with convection and conduction. In this paper, two different methods of turbulent flux calculation, eddy correlation and the bulk aerodynamic method are compared. Eddy correlation directly uses turbulence measurements to estimate heat flux whereas the bulk aerodynamic method relies on similarity theory to relate heat flux to mean flow quantities. A brief discussion of selection of averaging length based on flight altitude is included, as well as a comparison of errors introduced in averaging velocity as a scalar or as a vector. Errors introduced by averaging, including mesoscale flux enhancement, are evaluated for strong and weak wind cases during relatively light convection in the region. Finally, month to month variability in heat flux is evaluated in an effort to further understand the accuracy of various approximations used in flux calculation. / Graduation date: 2002

The climate and the exchange of heat between atmosphere and ocean are examined in a region adjacent to Washington and Oregon, and in two sub-regions adjacent to Oregon. The sub-regions are chosen such that one contains the nearshore upwelling region and the other borders it on the seaward side. The data (ship weather observations, 1953 to 1962) reveal the general seasonal variation of climatic factors in the regions studied and the effects of the nearshore upwelling of cold water on the climate over the coastal ocean region and the adjacent coastal land mass. In the nearshore sub-region, summer values of temperature (air, wet bulb, and sea surface) are lower than those to seaward, but winter values are higher inshore than to seaward. The effects of these differences, and of other factors, on the heat exchange processes are examined with the use of empirical equations. It is seen that the processes of evaporation and conduction are suppressed considerably and net long wave radiation is slightly suppressed in the upwelling region during the summer. The effects of the reduction of heat loss to the atmosphere in the summer upwelling region on the climate of coastal Oregon are seen to be a slight reduction of air temperatures and, despite reduced evaporation, a very slight increase of relative humidity. Monthly means of daily net heat exchange between the sea and the atmosphere are examined and correlated with the difference between monthly means of the heat used per day in the oceanic evaporation process and the monthly means of daily totals of heat estimated to be used in the evaporation from a shallow pan under climatic conditions identical to those accompanying the net heat exchange and oceanic evaporation. / Graduation date: 1965