Physical and biological mechanisms for planetary waves observed in satellite-derived chlorophyll

摘要: We examine the evidence for global propagation of planetary wavelike features in sea-surface chlorophyll. Over much midlatitude ocean, westward propagating signals are seen that travel at same speed as predicted long waves. then test three mechanisms production this signal. These are: horizontal (passive) north-south advection by wave against a mean background gradient; vertical upwelling nitrate, which is converted into chlorophyll; and chlorophyll itself. The tests involve comparisons amplitude phase signal with observations. advective process predicts an fluctuations fair agreement data, though both overestimating underestimating places. predictions difference between sea surface height signatures good data. biological mechanism could potentially give large field, but patterns (which everywhere negative) not accord Except few regions, small compared mechanism. conclude over most well explained processes, although we cannot rule out there exist locations where additional may be responsible least part