Analysis Of Heat Content In Marginal Seas East Of China

Observational ocean temperature and salinity data and SODA reanalysis data are used to calculate volume transport and heat transport across three sections and variation of vertical average sea temperature of the three sections in the ocean, results from different data show close variability and their correlations all past tests. Temperature and velocity data of SODA are used to calculate heat content in marginal seas east of China and heat transport into this areas. Surface heat flux data of NCEP/NCAR are used to calculate heat transport into the same area via sea surface. Seasonal variations and anomalies on longer time scales of the three factors are analyzed to study their mutual connections.Analysis shows heat content in marginal seas east of China has obvious seasonal variation, close to vertical average temperature, more in summer and autumn and less in winter and spring. The maximum exits in September and maximum appears in February. Net surface heat flux also shows obvious seasonal variation, ocean gains most heat in July and loses most heat in December. The averaged net heat flux in twelve months represents ocean releasing heat to the atmosphere. The seasonal variation of lateral net heat transport to this area shows more heat gain in summer than in winter. The heat budget in marginal seas east of China is studied. During March to August, the net heat gain of this area via surface and lateral is positive and increases heat content in this area. Net lateral heat flux is more than net surface heat flux in March and April and in other months marginal seas east of China gains heat mainly via surface. In September, the net surface and lateral heat flux and the variability of heat content are all close to zero. From October to February the next year, the net surface heat flux is negative and net lateral heat transport is positive, but there is more heat lose than heat gain, then heat content in this area decreases. The heat content anomalies of marginal seas east of China on longer time scales are primarily generated by changes of heat content in east China seas. Results of wavelet analysis show that during 1964 to 1969 and 1974 to 1985, there is about 3 years period interannual variation in heat content anomaly. These are agree to heat transport anomaly across south boundary. On decadal time scales, heat content anomaly represents alternate variations of positive-negative-positive-negative-positive, corresponding to heat transport anomaly across the section in low latitude, and the correlation between them is higher in the east China sea. It is said that the heat content anomaly in east China sea shows positive (negative) when the heat transport from low latitude takes positive (negative) anomaly, and then there is more (less) heatcont in marginal seas east of China. Furthermore, analysis finds that there is negative correlation between heat content anomaly and net surface heat flux anomaly, and the sea-air temperature difference plays an important role in net surface heat flux. The correlation shows negative on decadal time scales, when the heat content anomaly is positive (negative), there is more (less) heat released to the atmosphere.Three sections in the Kuroshio area are selected to show the depth distribution of sea temperature anomaly. Positive area is more widely than negative area when heat content anomaly is positive during 2004 to 2006, and the maximum positive anomaly exists in height during 100 to 200 meters under the sea surface. The distribution becomes nearly contrary during 2000 to 2003, and the height anomalies of the surface of constant temperature and wind anomalies in twelve months are almost the same when heat content anomaly changing from positive to negative.