Effects of the seasonal variation in chlorophyll concentration on sea surface temperature in the global ocean

The effects of biological heating on the upper-ocean temperature of the global ocean are investigated using two ocean-only experiments forced by prescribed atmospheric fields during 1990–2007,on with fixed constant chlorophyll concentration,and the other with seasonally varying chlorophyll concentration.Although the existence of high chlorophyll concentrations can trap solar radiation in the upper layer and warm the surface,cooling sea surface temperature(SST)can be seen in some regions and seasons.Seventeen regions are selected and classified according to their dynamic processes,and the cooling mechanisms are investigated through heat budget analysis.The chlorophyll-induced SST variation is dependent on the variation in chlorophyll concentration and net surface heat flux and on such dynamic ocean processes as mixing,upwelling and advection.The mixed layer depth is also an important factor determining the effect.The chlorophyll-induced SST warming appears in most regions during the local spring to autumn when the mixed layer is shallow,e.g.,low latitudes without upwelling and the mid-latitudes.Chlorophyll-induced SST cooling appears in regions experiencing strong upwelling,e.g.,the western Arabian Sea,west coast of North Africa,South Africa and South America,the eastern tropical Pacific Ocean and the Atlantic Ocean,and strong mixing(with deep mixed layer depth),e.g.,the mid-latitudes in winter.

Modulated-Power Implantable Neuromodulation Devices and Their Impact on Surrounding Tissue Temperatures

This project was intended to determine whether the preprogrammed time-varying recharge protocol for a battery incased in a neuromodulation implant can give rise to tissue temperatures that surpass a safe level or are otherwise benign. The study included the development of a highly accurate model of all the thermal processes that are activated by the recharging of the battery contained within the neuromodulation implant. The model was implemented by numerical simulations performed for several realistic operating conditions. The computed spatial and temporal tissue temperature distributions were employed to estimate possible tissue damage by making use of two independent methodologies. Independent calorimeter-based experiments were performed to provide validation for the calculated rates of heat generation in the coils of the implant. Spatial and temporal tissue temperature distributions extracted from the numerical simulations revealed the thermal effects associated with several realistic operating protocols. None of the operating protocols gave rise to temperatures above 42℃. Numerical values of thermal tissue damage metrics were determined and compared with accepted values which correspond to the absence and the presence of tissue damage. The experimentally determined rate of heat generation in the implant coils validated that from electrical measurements to within 2%. Both the tissue temperature results and the thermal damage metrics found no evidence of tissue injury when time-varying preprogrammed protocols are used in the recharging of neuromodulation implant-encased batteries.