Measurements of Near-Surface Sea Temperature From R/V Ron Brown During EPIC2001

During EPIC2001, the R/V Ron Brown carried various sensors measuring continuous time series of sea temperature at several depths. Above the IMET hull sensor permanently installed near the bow at 5.6 m depth, a through-the-hull temperature sensor was mounted at 2.0 m depth. A precision thermistor was towed at a nominal depth of 5 cm from a side boom, and an advanced IR radiometer viewed the sea surface to obtain the skin temperature. In this paper we present comparisons between these instruments, reflecting the effects of rainfall, solar penetration, and wind mixing at various depths in the ocean surface layer. The cool skin model featured in the TOGA-COARE bulk flux algorithm is shown to agree well with direct measurement during nighttime, but consistently under-predicts the magnitude of the cool-skin effect during daylight hours. All sensors record the dramatic reduction in sea temperature from around 26 degrees to 18 degrees within a distance of less than 100nm through the northern edge of the equatorial cold tongue.